Sealing device

Abstract

Provided is a sealing device which has high sound insulation and which applies less torque to a rotary shaft.　The sealing device seals a gap between an outer support member and the rotary shaft, which is disposed in a hole provided in the outer support member. The sealing device includes: an attachment part that is attached to the outer support member; a cylindrical part that is disposed inside the attachment part; a sliding part that is disposed inside the cylindrical part and that slidably contacts an outer peripheral surface of the rotary shaft; and an elastomer bellows part interposed between the attachment part and the cylindrical part. The bellows part includes: an outer inclined part having a truncated cone shape; an inner inclined part having a truncated cone shape inclined in the opposite direction to the outer inclined part; and a bent part connecting the outer inclined part and the inner inclined part. The outer inclined part includes an outer thick part thicker than the bent part. The inner inclined part includes an inner thick part thicker than the bent part.

Description

sealing device

[0001] The present invention relates to a sealing device suitable for use as a steering dust seal.

[0002] The steering dust seal is disposed on the front dash panel of the automobile, and the steering shaft is inserted therein so as to be freely rotatable (see Patent Document 1). The steering dust seal has a portion against which the steering shaft slides when the steering shaft rotates.

[0003] The steering dust seal has the function of preventing foreign matter (dust, muddy water, etc.) from entering the passenger compartment from the engine compartment, as well as suppressing the transmission of noise from the engine compartment to the passenger compartment.The steering dust seal is provided with a bellows portion made of an elastic material so that the angle of the steering shaft can be adjusted by the driver.

[0004] International Publication No. 2020 / 250577

[0005] In recent years, there has been an increasing demand for a quieter passenger compartment. It is also desirable that the resistance, i.e., torque, that a steering dust seal applies to a steering shaft when the steering shaft rotates is small.

[0006] Therefore, the present invention provides a sealing device that has high sound insulation and applies a small torque to a rotating shaft.

[0007] One aspect of the present invention provides a sealing device for sealing a gap between an outer support member and a rotating shaft disposed in a hole provided in the outer support member. The sealing device includes an annular mounting portion attached to the hole of the outer support member, a cylindrical portion disposed radially inside the mounting portion, a sliding portion disposed radially inside the cylindrical portion and in slidable contact with the outer peripheral surface of the rotating shaft, and an elastomer bellows portion interposed between the mounting portion and the cylindrical portion. The bellows portion has an outer inclined portion having a truncated cone shape, an inner inclined portion having a truncated cone shape inclined in the opposite direction to the outer inclined portion, and a bent portion having a bent cross-sectional shape connecting the outer inclined portion and the inner inclined portion. The outer inclined portion has an outer thick portion having a thickness greater than the thickness of the bent portion. The inner inclined portion has an inner thick portion having a thickness greater than the thickness of the bent portion.

[0008] In this embodiment, the outer and inner inclined portions of the bellows are provided with outer and inner thick portions, which effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, the curved portions of the bellows are thin and easily deformed, thereby reducing the resistance, i.e., torque, that the sealing device applies to the rotating shaft. Even if the elastomer forming the bellows hardens, especially in low-temperature environments, the thin curved portions are easily deformed. Because the resistance applied to the rotating shaft is small, noise generated by the sliding movement between the rotating shaft and the sliding portion is also reduced.

[0009] Fig. 1 is a partially cutaway perspective view showing a sealing device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the sealing device. Fig. 3 is a cross-sectional view of the sealing device in use. Fig. 4 is a cross-sectional view showing a state in which a first seal portion of the sealing device is manufactured using a mold. Fig. 5 is a cross-sectional view showing a state in which a second seal portion of the sealing device is manufactured using a mold. Fig. 6 is a partially cutaway perspective view showing a sealing device according to another embodiment of the present invention.

[0010] Various embodiments of the present invention will now be described with reference to the accompanying drawings, in which the drawings are not necessarily to scale and some features may be exaggerated or omitted.

[0011] As shown in Figures 1 to 3, a sealing device 1 according to an embodiment of the present invention has a composite structure having two seal portions 10, 50 (a first seal portion 10 and a second seal portion 50). Each of the seal portions 10, 50 is an annular component centered on a central axis Ax. The cross sections shown in Figures 1 to 3 are planes including the central axis Ax.

[0012] As shown in Fig. 3, the sealing device 1 according to the embodiment is a steering dust seal that seals a gap between an outer support member 2 and a rotating shaft (steering shaft) 4 disposed in a hole 2A provided in the outer support member 2. The rotating shaft 4 rotates around an axis Bx. In Fig. 3, the symbol E indicates a space on the engine compartment side, and the symbol P indicates a space on the passenger compartment side.

[0013] The outer support member 2 may be a front dash panel of an automobile, or may be a cylindrical member fixed to the front dash panel (an attachment member for attaching the sealing device 1 to the front dash panel).

[0014] An internal combustion engine (not shown) or an electric motor (not shown) may be disposed in the engine compartment.

[0015] The hole 2A has a large diameter hole portion 2B that opens into the space P on the passenger compartment side, and a small diameter hole portion 2C that is adjacent to the large diameter hole portion 2B and is located closer to the engine compartment than the large diameter hole portion 2B. The large diameter hole portion 2B and the small diameter hole portion 2C are circular holes. In an ideal case where the sealing device 1 is attached concentrically to the hole 2A, the central axis Ax of the sealing device 1 is also the central axis of the hole 2A.

[0016] The sealing device 1 has seal portions 10 and 50, and each of the seal portions 10 and 50 can be considered as a sealing device (steering dust seal).

[0017] The first seal portion (first sealing device) 10 is basically a highly elastic part made of elastomer. The seal portion 10 has an annular mounting portion 11 that is attached to the hole 2A of the outer support member 2, a cylindrical portion 12 that is disposed radially inside the mounting portion 11, and a bent bellows portion 13 that is interposed between the mounting portion 11 and the cylindrical portion 12 and connects them. The seal portion 10 further has a sliding portion 14 that is disposed radially inside the cylindrical portion 12 and that slidably contacts the outer peripheral surface of the rotating shaft 4.

[0018] The mounting portion 11 has an elastic ring 15 made of an elastomer and a rigid ring 16 made of a rigid material, such as a metal, fixed to the periphery of the elastic ring 15 .

[0019] The rigid ring 16 has a substantially L-shaped cross section. That is, the rigid ring 16 has a cylindrical sleeve 16a and a flange 16b that extends radially outward from one end of the sleeve 16a. The sleeve 16a is fitted (press-fitted) into the large-diameter hole portion 2B of the hole 2A of the outer support member 2.

[0020] A majority of the elastic ring 15 is disposed radially inward of the rigid ring 16. However, portions of the elastic ring 15 are fixed to the passenger compartment-side surface of the flange 16b, the outer peripheral surface of the flange 16b, and an outer peripheral portion of the engine compartment-side surface of the flange 16b. When the seal unit 10 is installed in the hole 2A, the portion 15a of the elastic ring 15 fixed to the outer peripheral portion of the engine compartment-side surface of the flange 16b is compressed along the central axis Ax between the end face of the outer support member 2 and the sleeve 16a of the rigid ring 16. Therefore, the portion 15a seals the gap between the rigid ring 16 and the outer support member 2, reduces the intrusion of foreign matter from the passenger compartment-side space P to the engine compartment-side space E, and prevents corrosion of the rigid ring 16 and / or the outer support member 2.

[0021] The end 16c of the sleeve 16a opposite the flange 16b has a smaller diameter than the other portions of the sleeve 16a. The end 16c is surrounded by the portion 15b of the elastic ring 15. The portion 15b has a radial lip 15c and an axial lip 15d. When the seal unit 10 is installed in the hole 2A, the radial lip 15c is pressed against the inner circumferential surface of the large-diameter hole portion 2B of the hole 2A and deforms radially inward, sealing the gap between the end 16c and the outer support member 2. In this state, the axial lip 15d is pressed against the step between the large-diameter hole portion 2B and the small-diameter hole portion 2C of the hole 2A and compressed, sealing the gap between the end 16c and the outer support member 2. Therefore, the radial lip 15c and the axial lip 15d reduce the intrusion of foreign matter from the space E on the engine compartment side to the space P on the passenger compartment side.

[0022] The cylindrical portion 12 and the bellows portion 13 are formed from the same elastomer as the elastic ring 15 of the mounting portion 11. Preferably, the elastic ring 15, the cylindrical portion 12 and the bellows portion 13 are integrally formed.

[0023] The sliding portion 14 disposed inside the cylindrical portion 12 is made of a resin material that is harder than elastomer and has a smaller coefficient of friction. Preferred resin materials include polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), and polyphenylene sulfide (PPS).

[0024] The sliding portion 14 may be fixed to the cylindrical portion 12 with an adhesive. Alternatively, the sliding portion 14 may have a protrusion, and the protrusion may be fitted into a groove formed in the cylindrical portion 12, thereby fixing the sliding portion 14 to the cylindrical portion 12.

[0025] When the rotating shaft 4 rotates, the outer peripheral surface of the rotating shaft 4 slides against the inner peripheral surface of the sliding portion 14. Because the sliding portion 14 is made of a resin with a low coefficient of friction, the generation of abnormal noise due to friction between the outer peripheral surface of the rotating shaft 4 and the inner peripheral surface of the sliding portion 14 is reduced even when the rotating shaft 4 rotates.

[0026] Although not absolutely necessary, grease may be provided between the inner peripheral surface of the sliding portion 14 and the outer peripheral surface of the rotating shaft 4. The grease further reduces friction between the outer peripheral surface of the rotating shaft 4 and the inner peripheral surface of the sliding portion 14. A number of grooves for holding grease may be formed on the inner peripheral surface of the sliding portion 14.

[0027] A radial lip 12a is formed on the end of the cylindrical portion 12 on the passenger compartment side. The radial lip 12a extends radially inward toward the passenger compartment side. The radial lip 12a restrains the sliding portion 14 and applies a binding force to the sliding portion 14. The tip of the radial lip 12a may be in slidable contact with the outer circumferential surface of the rotating shaft 4.

[0028] The rotating shaft 4 is a steering shaft provided in a tilt steering mechanism of an automobile. Therefore, the rotating shaft 4 can be tilted by the driver. That is, the angle of the rotating shaft 4 relative to the hole 2A of the outer support member 2 is adjustable. The rotating shaft 4 can also be made eccentric with respect to the hole 2A. The bellows portion 13 is made of an elastomer and has a curved shape, so it is easily elastically deformed. The elastic deformation of the bellows portion 13 allows the rotating shaft 4 to move, i.e., tilt and eccentric, and also allows the sliding portion 14 to contact the outer surface of the rotating shaft 4. Figure 3 shows the state in which the rotating shaft 4 is tilted and eccentric with respect to the hole 2A.

[0029] The bellows portion 13 has an inclined portion 20, a bent portion 21, an inclined portion 22, an inclined portion 23, an inclined portion 24, an inclined portion 25, and an inclined portion 26. The inclined portions 20, 22, 24, and 26 have a truncated cone shape. However, the inclined direction of the inclined portions 20 and 24 is opposite to the inclined direction of the inclined portions 22 and 26.

[0030] The inclined portion 20 is connected to the passenger compartment side edge of the sliding portion 14 and extends toward the passenger compartment side. The area of ​​the circular region surrounded by the passenger compartment side edge of the inclined portion 20 is larger than the area of ​​the circular region surrounded by the engine compartment side edge of the inclined portion 20 connected to the sliding portion 14.

[0031] The bent portion 21 has a bent cross-sectional shape and connects the passenger compartment side end edge of the inclined portion 20 and the passenger compartment side end edge of the inclined portion 22 .

[0032] The inclined portion 22 extends from the bent portion 21 toward the engine compartment side. The area of ​​the circular region enclosed by the edge of the inclined portion 22 on the engine compartment side is larger than the area of ​​the circular region enclosed by the edge of the inclined portion 22 connected to the bent portion 21 on the passenger compartment side.

[0033] The bent portion 23 has a bent (arcuate) cross-sectional shape, and connects the engine room side edge of the inclined portion 22 and the engine room side edge of the inclined portion 24 .

[0034] The inclined portion 24 extends from the bent portion 23 toward the passenger compartment. The area of ​​the circular region enclosed by the passenger compartment-side edge of the inclined portion 24 is larger than the area of ​​the circular region enclosed by the engine compartment-side edge of the inclined portion 24 connected to the bent portion 23.

[0035] The bent portion 25 has a bent (arcuate) cross-sectional shape, and connects the passenger compartment side end edge of the inclined portion 24 and the passenger compartment side end edge of the inclined portion 26 .

[0036] The inclined portion 26 extends from the bent portion 25 toward the engine compartment side and is connected to the elastic ring 15 of the mounting portion 11. The area of ​​the circular region surrounded by the engine compartment side edge of the inclined portion 26 connected to the elastic ring 15 is larger than the area of ​​the circular region surrounded by the passenger compartment side edge of the inclined portion 26 connected to the bent portion 25.

[0037] Thus, inclined portion 22 is disposed radially outward of inclined portion 20, inclined portion 24 is disposed radially outward of inclined portion 22, and inclined portion 26 is disposed radially outward of inclined portion 24. Therefore, inclined portion 22 is an outer inclined portion for inclined portion 20, inclined portion 24 is an outer inclined portion for inclined portion 22, and inclined portion 26 is an outer inclined portion for inclined portion 24.

[0038] In the following description, the thickness of the portions of the seal portion 10 refers to the thickness of the seal portion 10 when it is not elastically deformed.

[0039] As shown in FIG. 2, the ramp 20 has a uniform thickness t1, and the ramp 26 also has a uniform thickness t2.

[0040] Consider the inclined portions 22 and 24 and the adjacent bent portions 21, 23, and 25. The inclined portion 24 is an outer inclined portion relative to the inclined portion 22, and the inclined portion 22 is an inner inclined portion relative to the inclined portion 24.

[0041] 2, bent portion 23 has an arc-shaped cross-sectional shape and a uniform thickness t3. Bent portion 25 also has an arc-shaped cross-sectional shape and a uniform thickness t4. The thickness of bent portion 21 is not uniform, and bent portion 21 has a minimum thickness t5 at a position adjacent to inclined portion 22. Thicknesses t2, t3, t4 and minimum thickness t5 are approximately equal.

[0042] The outer inclined portion 24 has an outer thin portion 30, an outer thickness change portion 31, an outer thick portion 32, an outer thickness change portion 33, and an outer thin portion 34. The outer thin portion 30 is connected to the bent portion 23 and has the same uniform thickness t3 as the bent portion 23. The outer thick portion 32 has a uniform thickness t6 that is greater than the thickness t3 of the bent portion 23 and the outer thin portion 30. The outer thickness change portion (first outer thickness change portion) 31 connects the outer thin portion 30 and the outer thick portion 32 and has a thickness that gradually and linearly increases from the outer thin portion 30 to the outer thick portion 32.

[0043] The outer thickness change portion (second outer thickness change portion) 33 extends from the outer thick portion 32 in the opposite direction from the outer thickness change portion 31. The outer thin portion 34 connects the outer thickness change portion 33 to the bent portion 25. The outer thin portion 34 has a thickness that gradually and linearly increases from the bent portion 25 toward the outer thickness change portion 33. Therefore, the end of the outer thin portion 34 on the bent portion 25 side locally has the same thickness t4 as the bent portion 25. The outer thickness change portion 33 has a thickness that rapidly and linearly increases from the outer thin portion 34 toward the outer thick portion 32. In other words, the outer thickness change portion 33 has a thickness that linearly decreases from the outer thick portion 32 toward the outer thin portion 34. The thickness t6 of the outer thick portion 32 is greater than the thickness t4 of the bent portion 25.

[0044] One surface of the outer inclined portion 24 (the surface facing the engine compartment) has a smooth truncated cone shape. However, the other surface of the outer inclined portion 24 (the surface facing the passenger compartment) has a protruding portion due to a change in thickness of the inclined portion 24. A protruding portion may be formed not only on the surface of the outer inclined portion 24 facing the passenger compartment, but also on the surface of the outer inclined portion 24 facing the engine compartment.

[0045] The inner inclined portion 22 has an inner thin portion 35, an inner thickness change portion 36, an inner thick portion 37, and an inner thickness change portion 38. The inner thin portion 35 is connected to the bent portion 23 and has the same uniform thickness t3 as the bent portion 23. The inner thick portion 37 has a uniform thickness t7 that is greater than the thickness t3 of the bent portion 23 and the inner thin portion 35. The inner thickness change portion (first inner thickness change portion) 36 connects the inner thin portion 35 and the inner thick portion 37 and has a thickness that gradually and linearly increases from the inner thin portion 35 to the inner thick portion 37.

[0046] The inner thickness change portion (second inner thickness change portion) 38 extends from the inner thickened portion 37 in the opposite direction from the inner thickness change portion 36 and connects the inner thickened portion 37 to the bent portion 21. The inner thickness change portion 38 has a thickness that increases abruptly and linearly from the bent portion 21 to the inner thickened portion 37. In other words, the inner thickness change portion 38 has a thickness that decreases linearly from the inner thickened portion 37 to the bent portion 21. Therefore, the end of the inner thickness change portion 38 on the bent portion 21 side locally has the same thickness as the minimum thickness t5 of the bent portion 21. The thickness t7 of the inner thickened portion 37 is greater than the thickness of any point in the bent portion 21.

[0047] One surface of the inner inclined portion 22 (the surface facing the engine compartment) is a smooth truncated cone. However, the other surface of the inner inclined portion 22 (the surface facing the passenger compartment) has a protruding portion due to a change in thickness of the inclined portion 22. A protruding portion may be formed not only on the surface of the inner inclined portion 22 facing the passenger compartment, but also on the surface of the outer inclined portion 24 facing the engine compartment.

[0048] In the first seal portion 10, the outer inclined portion 24 and the inner inclined portion 22 of the bellows portion 13 are provided with an outer thick portion 32 and an inner thick portion 37, respectively. These thick portions 32, 37 effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, the bent portion 23, the outer thin portions 30, 34, and the inner thin portion 35 of the bellows portion 13 are thin and easily deformable, thereby reducing the resistance, i.e., torque, that the seal portion 10 applies to the rotating shaft 4. Even if the elastomer forming the bellows portion 13 hardens, especially in low-temperature environments, these thin portions are easily deformed. Because the resistance applied to the rotating shaft 4 is small, noise generated by sliding between the rotating shaft 4 and the sliding portion 14 is also reduced.

[0049] Preferably, the thickness t6 of the outer thick portion 32 and the thickness t7 of the inner thick portion 37 are 1.1 times or more the thickness t3 of the bent portion 23. In this case, the outer thick portion 32 and the inner thick portion 37 effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Furthermore, because the bent portion 23 is thin, the resistance, i.e., torque, that the seal portion 10 applies to the rotating shaft 4 can be reduced. More preferably, the thickness t6 of the outer thick portion 32 and the thickness t7 of the inner thick portion 37 are 1.3 times or more the thickness t3 of the bent portion 23.

[0050] Preferably, the length L4 of the outer thick portion 32 is greater than 1 / 10.6 of the length L3 of the outer inclined portion 24 having a truncated cone shape including the outer thin portion 30, the first outer thickness changing portion 31, the outer thick portion 32, and the second outer thickness changing portion 33. In this case, since the length L3 of the outer thick portion 32 having a large thickness in the outer inclined portion 24 having a truncated cone shape is long, the weight of the outer inclined portion 24 is large, and the outer inclined portion 24 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment.

[0051] Preferably, the length L2 of the inner thick portion 37 is greater than 1 / 5.3 of the length L1 of the inner inclined portion 22 having a truncated cone shape including the inner thin portion 35, the first inner thickness varying portion 36, the inner thick portion 37, and the second inner thickness varying portion 38. In this case, since the length L2 of the inner thick portion 37 having a large thickness in the inner inclined portion 22 having a truncated cone shape is large, the weight of the inner inclined portion 22 is large, and the inner inclined portion 22 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment.

[0052] Furthermore, for the inner inclined portion 22, the bent portion 21 is an inner connecting portion that connects the cylindrical portion 12 and the inner inclined portion 22. The bent portion (inner connecting portion) 21 has a thickness that is smaller than the thickness t6 of the outer thick portion 32 and the thickness t7 of the inner thick portion 37. Therefore, the bent portion 21 having a small thickness is more likely to deform, and therefore the resistance, i.e., torque, that the seal portion 10 applies to the rotating shaft 4 can be further reduced.

[0053] Furthermore, for the outer inclined portion 24, the bent portion 25 and the inclined portion 26 are outer connecting portions that connect the mounting portion 11 and the outer inclined portion 24. The thickness t4 of the bent portion (outer connecting portion) 25 and the thickness t2 of the inclined portion (outer connecting portion) 26 are smaller than the thickness t6 of the outer thick portion 32 and the thickness t7 of the inner thick portion 37. Therefore, the bent portion 25 and the inclined portion 26, which have smaller thicknesses, are more likely to deform, and the resistance, i.e., torque, that the seal portion 10 applies to the rotating shaft 4 can be further reduced.

[0054] Preferably, the thickness t6 of the outer thick portion 32 is 1.1 times or more the thickness t4 of the bent portion (outer connection portion) 25 and the thickness t2 of the inclined portion (outer connection portion) 26. In this case, the outer thick portion 32 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, because the thicknesses of the bent portion (outer connection portion) 25 and the inclined portion (outer connection portion) 26 are small, the resistance, i.e., torque, that the sealing device 10 applies to the rotating shaft 4 can be reduced.

[0055] Outer inclined portion 24 and inner inclined portion 22 have thickness transition portions 31, 33, 36, and 38, which gradually change in thickness. Therefore, stress concentration is unlikely to occur in outer inclined portion 24 and inner inclined portion 22. Furthermore, as shown in Figure 4, when bellows portion 13 is manufactured using molds 80 and 81, thickness transition portions 31, 33, 36, and 38, which gradually change in thickness, do not hinder the flow of elastomer in the cavities inside molds 80 and 81, so the elastomer can easily spread throughout the interior of the mold that molds bellows portion 13.

[0056] 4, bellows portion 13 does not have undercuts that would prevent bellows portion 13 from being axially separated from dies 80, 81 that molded bellows portion 13. Outer sloped portion 24 and inner sloped portion 22 have thickness transitions 31, 33, 36, 38 that gradually change in thickness, but when bellows portion 13 is manufactured using dies 80, 81, if dies 80, 81 are separated from each other in the axial direction, bellows portion 13 can be easily removed from dies 80, 81.

[0057] In particular, the outer thick portion 32 of the outer inclined portion 24 protrudes radially inward (toward the passenger compartment) with respect to the truncated cone shape of the outer inclined portion 24, but the inner peripheral surface (the surface facing the passenger compartment) of the first outer thickness varying portion 31 of the outer inclined portion 24 is substantially cylindrical, so that the mold 81 can be easily separated from the bellows portion 13. Furthermore, the inner thick portion 37 of the inner inclined portion 22 protrudes radially outward (toward the passenger compartment) with respect to the truncated cone shape of the inner inclined portion 22, but the outer peripheral surface (the surface facing the passenger compartment) of the first inner thickness varying portion 36 of the inner inclined portion 22 is substantially cylindrical, so that the mold 81 can be easily separated from the bellows portion 13.

[0058] The second seal portion (second sealing device) 50 is also basically a highly elastic part made of elastomer. The seal portion 50 has an annular mounting portion 51 that is attached to the hole 2A of the outer support member 2, a cylindrical portion 52 that is arranged radially inside the mounting portion 51, and a bent bellows portion 53 that is interposed between the mounting portion 51 and the cylindrical portion 52 and connects them. Furthermore, the seal portion 50 has a sliding portion 54 that is arranged radially inside the cylindrical portion 52 and that slidably contacts the outer peripheral surface of the rotating shaft 4.

[0059] The mounting portion 51 has an elastic ring 55 made of an elastomer and a rigid ring 56 made of a rigid material, such as a metal, fixed to the periphery of the elastic ring 55 .

[0060] The rigid ring 56 has a substantially L-shaped cross section. That is, the rigid ring 56 has a cylindrical sleeve 56a and an inner flange 56b extending radially inward from one end of the sleeve 56a. The sleeve 56a may be directly fitted (press-fitted) into the hole 2A of the outer support member 2, but in this embodiment, it is fitted (press-fitted) into the end of the mounting portion 11 of the first seal unit 10 and attached to the hole 2A. More specifically, the end of the mounting portion 11 into which the sleeve 56a is fitted is the end of the elastic ring 15, which is surrounded and reinforced by the end 16c of the rigid ring 16. Therefore, with respect to the second seal unit 50, the mounting portion 11 of the first seal unit 10 can be considered to be the outer support member.

[0061] The elastic ring 55 is disposed radially inside the sleeve 56 a of the rigid ring 56 .

[0062] The rigid ring 56, which is difficult to deform, adheres closely to the inner peripheral surface of the end of the elastic ring 15, which is easily deformed, and reduces the intrusion of foreign matter from the space E on the engine compartment side to the space P on the passenger compartment side.

[0063] The cylindrical portion 52 and the bellows portion 53 are formed from the same elastomer as the elastic ring 55 of the mounting portion 51. Preferably, the elastic ring 55, the cylindrical portion 52, and the bellows portion 53 are integrally formed.

[0064] The sliding portion 54 disposed inside the cylindrical portion 52 is made of a resin material that is harder than elastomer and has a small coefficient of friction, just like the sliding portion 14 of the seal portion 10 .

[0065] The sliding portion 54 may be fixed to the cylindrical portion 52 with an adhesive. Alternatively, the sliding portion 54 may have a protrusion, and the protrusion may be fitted into a groove formed in the cylindrical portion 52, thereby fixing the sliding portion 54 to the cylindrical portion 52.

[0066] When the rotating shaft 4 rotates, the outer peripheral surface of the rotating shaft 4 slides against the inner peripheral surface of the sliding portion 54. Because the sliding portion 54 is made of a resin with a low friction coefficient, even when the rotating shaft 4 rotates, the generation of abnormal noise due to friction between the outer peripheral surface of the rotating shaft 4 and the inner peripheral surface of the sliding portion 54 is reduced.

[0067] Although not absolutely necessary, grease may be provided between the inner peripheral surface of the sliding portion 54 and the outer peripheral surface of the rotating shaft 4. The grease further reduces friction between the outer peripheral surface of the rotating shaft 4 and the inner peripheral surface of the sliding portion 54. A number of grooves for holding grease may be formed on the inner peripheral surface of the sliding portion 54.

[0068] A radial lip 52a is formed on the end of the cylindrical portion 52 on the engine compartment side. The radial lip 52a extends toward the engine compartment and radially inward. The radial lip 52a restrains the sliding portion 54 and applies a binding force to the sliding portion 54. The tip of the radial lip 52a may be in slidable contact with the outer circumferential surface of the rotating shaft 4.

[0069] Although not absolutely necessary, a radial lip 52b is also formed on the end of the cylindrical portion 52 on the passenger compartment side. The radial lip 52b extends radially inward toward the passenger compartment side. The tip of the radial lip 52b is in slidable contact with the outer circumferential surface of the rotating shaft 4.

[0070] Although not absolutely necessary, a reinforcing ring 52c is embedded in the cylindrical portion 52. The reinforcing ring 52c is made of a rigid material, such as metal, and suppresses deformation of the cylindrical portion 52, allowing the sliding portion 54 and the radial lip 52b to contact the rotating shaft 4 in a stable position.

[0071] The bellows portion 53 is made of elastomer and has a curved shape, which makes it susceptible to elastic deformation. The elastic deformation of the bellows portion 53 allows the rotation shaft 4 to move, i.e., tilt and eccentricity, and also allows the sliding portion 54 to contact the outer circumferential surface of the rotation shaft 4. As described above, Figure 3 shows a state in which the rotation shaft 4 is tilted and eccentric with respect to the hole 2A.

[0072] The bellows portion 53 has a bent portion 61, an inclined portion 62, a bent portion 63, an inclined portion 64, and an inclined portion 65. The inclined portions 62 and 64 have a truncated cone shape. However, the inclined direction of the inclined portion 64 is opposite to the inclined direction of the inclined portion 62.

[0073] The bent portion 61 has a bent cross-sectional shape and connects the passenger compartment side end edge of the cylindrical portion 52 and the passenger compartment side end edge of the inclined portion 62 .

[0074] The inclined portion 62 extends from the bent portion 61 toward the engine compartment side. The area of ​​the circular region enclosed by the edge of the inclined portion 62 on the engine compartment side is larger than the area of ​​the circular region enclosed by the edge of the inclined portion 62 connected to the bent portion 61 on the passenger compartment side.

[0075] The bent portion 63 has a bent (arcuate) cross-sectional shape, and connects the engine room side edge of the inclined portion 62 and the engine room side edge of the inclined portion 64 .

[0076] The inclined portion 64 extends from the bent portion 63 toward the passenger compartment side. The area of ​​the circular region enclosed by the edge of the inclined portion 64 on the passenger compartment side is larger than the area of ​​the circular region enclosed by the edge of the inclined portion 64 connected to the bent portion 63 on the engine compartment side.

[0077] The bent portion 65 has a bent cross-sectional shape and connects the passenger compartment side edge of the inclined portion 64 to the elastic ring 55 of the mounting portion 51. The inner flange 56b of the rigid ring 56 of the mounting portion 51 is embedded in the bent portion 65.

[0078] In this way, the inclined portion 64 is disposed radially outward of the inclined portion 62. Therefore, the inclined portion 64 is an outer inclined portion relative to the inclined portion 62, and the inclined portion 62 is an inner inclined portion relative to the inclined portion 64.

[0079] In the following description, the thickness of the portions of the seal portion 50 refers to the thickness of the seal portion 50 when it is not elastically deformed.

[0080] 2, bent portion 63 has an arc-shaped cross section and a uniform thickness t8. Bent portion 65 does not have a uniform thickness, but has a minimum thickness t9 at a position adjacent to inclined portion 64. Bent portion 61 also does not have a uniform thickness, but has a minimum thickness t10 at a position adjacent to inclined portion 62.

[0081] The outer inclined portion 64 has an outer thin portion 70, an outer thickness change portion 71, an outer thick portion 72, and an outer thickness change portion 73. The outer thin portion 70 is connected to the bent portion 63 and has the same uniform thickness t8 as the bent portion 63. The outer thick portion 72 has a uniform thickness t11 that is greater than the thickness t8 of the bent portion 63 and the outer thin portion 70. The outer thickness change portion (first outer thickness change portion) 71 connects the outer thin portion 70 and the outer thick portion 72 and has a thickness that increases suddenly and linearly from the outer thin portion 70 to the outer thick portion 72.

[0082] The outer thickness change portion (second outer thickness change portion) 73 extends from the outer thickened portion 72 in the opposite direction from the outer thickened portion 71 and connects the outer thickened portion 72 to the bent portion 65. The outer thickness change portion 73 has a thickness that gradually and linearly increases from the bent portion 65 toward the outer thickness change portion 73. In other words, the outer thickness change portion 73 has a thickness that linearly decreases from the outer thickness change portion 73 toward the bent portion 65. Therefore, the end of the outer thickness change portion 73 on the bent portion 65 side locally has the same thickness as the minimum thickness t9 of the bent portion 65. The thickness t11 of the outer thickened portion 72 is greater than the minimum thickness t9 of the bent portion 65.

[0083] One surface of the outer inclined portion 64 (the surface facing the passenger compartment) has a smooth truncated cone shape. However, the other surface of the outer inclined portion 64 (the surface facing the engine compartment) has a protruding portion due to a change in thickness of the inclined portion 64. A protruding portion may be formed not only on the surface of the outer inclined portion 64 facing the engine compartment, but also on the surface of the outer inclined portion 64 facing the passenger compartment.

[0084] The inner inclined portion 62 has an inner thin portion 75, an inner thickness change portion 76, an inner thick portion 77, and an inner thickness change portion 78. The inner thin portion 75 is connected to the bent portion 63 and has the same uniform thickness t8 as the bent portion 63. The inner thick portion 77 has a uniform thickness t12 that is greater than the thickness t8 of the bent portion 63 and the inner thin portion 75. The inner thickness change portion (first inner thickness change portion) 76 connects the inner thin portion 75 and the inner thick portion 77 and has a thickness that increases suddenly and linearly from the inner thin portion 75 to the inner thick portion 77.

[0085] The inner thickness changing portion (second inner thickness changing portion) 78 extends from the inner thickened portion 77 in the opposite direction from the inner thickness changing portion 76 and connects the inner thickened portion 77 to the bent portion 61. The inner thickness changing portion 78 has a thickness that increases abruptly and linearly from the bent portion 61 to the inner thickened portion 77. In other words, the inner thickness changing portion 78 has a thickness that decreases linearly from the inner thickened portion 77 to the bent portion 61. Therefore, the end of the inner thickness changing portion 78 on the bent portion 61 side locally has a thickness that is the same as the minimum thickness t10 of the bent portion 61.

[0086] One surface of the inner inclined portion 62 (the surface facing the passenger compartment) has a smooth truncated cone shape. However, the other surface of the inner inclined portion 62 (the surface facing the engine compartment) has a protruding portion due to a change in thickness of the inclined portion 62. A protruding portion may be formed not only on the surface of the inner inclined portion 62 facing the engine compartment, but also on the surface of the inner inclined portion 62 facing the passenger compartment.

[0087] In the second seal portion 50, the outer inclined portion 64 and the inner inclined portion 62 of the bellows portion 53 are provided with an outer thick portion 72 and an inner thick portion 77, respectively. These thick portions 72, 77 effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, the bent portion 63, the outer thin portion 70, and the inner thin portion 75 of the bellows portion 53 are thin and easily deformable, thereby reducing the resistance, i.e., torque, that the seal portion 50 applies to the rotating shaft 4. Even if the elastomer forming the bellows portion 53 hardens, especially in low-temperature environments, these thin portions are easily deformed. Because the resistance applied to the rotating shaft 4 is small, noise generated by sliding between the rotating shaft 4 and the sliding portion 54 is also reduced.

[0088] Preferably, the thickness t11 of the outer thick portion 72 and the thickness t12 of the inner thick portion 77 are 1.1 times or more the thickness t8 of the bent portion 63. In this case, the outer thick portion 72 and the inner thick portion 77 effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Furthermore, because the bent portion 63 is thin, the resistance, i.e., torque, that the seal portion 50 applies to the rotating shaft 4 can be reduced. More preferably, the thickness t11 of the outer thick portion 72 and the thickness t12 of the inner thick portion 77 are 1.3 times or more the thickness t8 of the bent portion 63.

[0089] Preferably, the length L8 of the outer thick portion 72 is greater than 1 / 3.2 of the length L7 of the outer inclined portion 64 having a truncated cone shape including the outer thin portion 70, the first outer thickness changing portion 71, the outer thick portion 72, and the second outer thickness changing portion 73. In this case, since the length L8 of the outer thick portion 72 having a large thickness in the outer inclined portion 64 having a truncated cone shape is long, the weight of the outer inclined portion 64 is large, and the outer inclined portion 64 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment.

[0090] Preferably, the length L6 of the inner thick portion 77 is greater than 1 / 3.8 of the length L5 of the inner inclined portion 62 having a truncated cone shape including the inner thin portion 75, the first inner thickness varying portion 76, the inner thick portion 77, and the second inner thickness varying portion 78. In this case, since the length L6 of the inner thick portion 77 having a large thickness in the inner inclined portion 62 having a truncated cone shape is large, the weight of the inner inclined portion 62 is large, and the inner inclined portion 62 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment.

[0091] Furthermore, for the inner inclined portion 62, the bent portion 61 is an inner connecting portion that connects the cylindrical portion 52 and the inner inclined portion 62. The bent portion (inner connecting portion) 61 has a thickness that is smaller than the thickness t11 of the outer thick portion 72 and the thickness t12 of the inner thick portion 77. Therefore, the bent portion 61 having a small thickness is more likely to deform, and therefore the resistance, i.e., torque, that the seal portion 50 applies to the rotating shaft 4 can be further reduced.

[0092] Preferably, the thickness t12 of the inner thick portion 77 of the inclined portion 62 is 1.1 times or more the maximum thickness t13 of the bent portion (inner connecting portion) 61. In this case, the inner thick portion 77 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment. In addition, because the bent portion 61 is thin, the resistance, i.e., torque, that the seal portion 10A applies to the rotating shaft 4 can be reduced.

[0093] Furthermore, for the outer inclined portion 64, the bent portion 65 is an outer connecting portion that connects the mounting portion 51 and the outer inclined portion 64. The minimum thickness t9 of the bent portion (outer connecting portion) 65 is smaller than the thickness t11 of the outer thick portion 72 and the thickness t12 of the inner thick portion 77. Therefore, the bent portion 65 with a small thickness is more likely to deform, and the resistance, i.e., torque, that the seal portion 50 applies to the rotating shaft 4 can be further reduced.

[0094] Outer inclined portion 64 and inner inclined portion 62 have thickness transition portions 71, 73, 76, and 78, which gradually change in thickness. Therefore, stress concentration is unlikely to occur in outer inclined portion 64 and inner inclined portion 62. Furthermore, as shown in Figure 5, when bellows portion 53 is manufactured using molds 90 and 91, thickness transition portions 71, 73, 76, and 78, which gradually change in thickness, do not hinder the flow of elastomer in the cavities inside molds 90 and 91, so the elastomer can easily spread throughout the mold that molds bellows portion 53.

[0095] 5, bellows portion 53 does not have undercuts that would prevent bellows portion 53 from being axially separated from dies 90, 91 that molded bellows portion 53. Outer sloped portion 64 and inner sloped portion 62 have thickness transitions 71, 73, 76, 78 that gradually change in thickness, but when bellows portion 53 is manufactured using dies 90, 91, if dies 90, 91 are separated from each other in the axial direction, bellows portion 53 can be easily removed from dies 90, 91.

[0096] In particular, the outer thick portion 72 of the outer inclined portion 64 protrudes radially outward (toward the engine compartment) with respect to the truncated cone shape of the outer inclined portion 64, but the outer peripheral surface (the surface facing the engine compartment) of the second outer thickness varying portion 73 of the outer inclined portion 64 is substantially cylindrical, which makes it easy to separate the mold 90 from the bellows portion 53. Furthermore, the inner thick portion 77 of the inner inclined portion 62 protrudes radially inward (toward the engine compartment) with respect to the truncated cone shape of the inner inclined portion 62, but the inner peripheral surface (the surface facing the engine compartment) of the second inner thickness varying portion 78 of the inner inclined portion 62 is substantially cylindrical, which makes it easy to separate the mold 90 from the bellows portion 53.

[0097] As described above, the sealing device 1 according to this embodiment has two seal portions 10, 50 having similar structures. The double structure having the seal portions 10, 50 further improves the function of suppressing sound transmission from the engine compartment space E to the passenger compartment space P, and further improves the function of suppressing the intrusion of foreign matter from the engine compartment space E to the passenger compartment space P.

[0098] 2, when the seal portions 10, 50 are not elastically deformed, the bent portion 61 of the second seal portion 50 axially overlaps the bent portion 21 of the first seal portion 10, and the inclined portion 62 axially overlaps the inclined portion 22. Also, at this time, the bent portion 63 axially overlaps the bent portion 23, the inclined portion 64 axially overlaps the outer thin-walled portion 34, and the bent portion 65 axially overlaps the bent portion 25. In the second seal portion 50, the portion formed by the inclined portions 62, 63, and 64 is convex toward the engine compartment, and similarly, in the first seal portion 10, the portion formed by the inclined portions 22, 23, and 24 is also convex toward the engine compartment.

[0099] In such a double structure having seal portions 10 and 50, it is desirable that bellows portion 13 of seal portion 10 and bellows portion 53 of seal portion 50 do not collide with each other when rotating shaft 4 is inclined and eccentric with respect to hole 2A as shown in Figure 3. In the illustrated embodiment, bellows portion 13 and bellows portion 53 are sufficiently separated from each other in the axial direction, but in a configuration in which bellows portion 13 and bellows portion 53 are close to each other in the axial direction, it is particularly desirable that thick portions 32 and 37 of bellows portion 13 do not collide with thick portions 72 and 77 of bellows portion 53.

[0100] Therefore, the outer thick portion 32 of the outer inclined portion 24 of the first seal portion 10 protrudes toward the opposite side (passenger compartment side) of the bellows portion 53 of the second seal portion 50 with respect to the truncated cone shape of the outer inclined portion 24, and the surface of the outer inclined portion 24 of the first seal portion 10 facing the bellows portion 53 of the second seal portion 50 (the surface facing the engine compartment) has a smooth truncated cone shape. Also, the inner thick portion 37 of the inner inclined portion 22 of the first seal portion 10 protrudes toward the opposite side (passenger compartment side) of the bellows portion 53 of the second seal portion 50 with respect to the truncated cone shape of the inner inclined portion 22, and the surface of the inner inclined portion 22 of the first seal portion 10 facing the bellows portion 53 of the second seal portion 50 (the surface facing the engine compartment) has a smooth truncated cone shape.

[0101] On the other hand, the outer thick portion 72 of the outer inclined portion 64 of the second seal portion 50 protrudes toward the opposite side (engine compartment side) of the bellows portion 13 of the first seal portion 10 relative to the truncated cone shape of the outer inclined portion 64, and the surface of the outer inclined portion 64 of the second seal portion 50 facing the bellows portion 13 of the first seal portion 10 (the surface facing the crew compartment) has a smooth truncated cone shape. Also, the inner thick portion 77 of the inner inclined portion 62 of the second seal portion 50 protrudes toward the opposite side (engine compartment side) of the bellows portion 13 of the first seal portion 10 relative to the truncated cone shape of the inner inclined portion 62, and the surface of the inner inclined portion 62 of the second seal portion 50 facing the bellows portion 13 of the first seal portion 10 (the surface facing the crew compartment) has a smooth truncated cone shape.

[0102] Therefore, even if the axial distance between the bellows portion 13 of the first seal portion 10 and the bellows portion 53 of the second seal portion 50 is small, the outer inclined portion 24 (particularly the outer thick portion 32) of the first seal portion 10 is unlikely to collide with the outer inclined portion 64 (particularly the outer thick portion 72) of the second seal portion 50, and the inner inclined portion 22 (particularly the inner thick portion 37) of the first seal portion 10 is unlikely to collide with the inner inclined portion 62 (particularly the inner thick portion 77) of the second seal portion 50.

[0103] Fig. 6 is a partially cutaway perspective view showing a sealing device 1A according to another embodiment of the present invention. The cross section shown in Fig. 6 is a plane including the central axis Ax.

[0104] The sealing device 1A has a composite structure having two seal portions 10A, 50A (a first seal portion 10A and a second seal portion 50A). Each of the seal portions 10A, 50A is an annular part centered on the central axis Ax. Each of the seal portions 10A, 50A can be considered a sealing device (a steering dust seal).

[0105] Similar to the seal unit 10, the first seal unit (first sealing device) 10A has an annular mounting portion 11, a cylindrical portion 12 disposed radially inside the mounting portion 11, and a bent bellows portion 113 interposed between the mounting portion 11 and the cylindrical portion 12 to connect them. The cylindrical portion 12 and the bellows portion 113 are formed from the same elastomer as the elastic ring 15 of the mounting unit 11. Preferably, the elastic ring 15, the cylindrical portion 12, and the bellows portion 113 are integrally formed. Furthermore, the seal unit 10 has a sliding portion 14 disposed radially inside the cylindrical portion 12 and in slidable contact with the outer peripheral surface of the rotating shaft 4. The mounting portion 11, the cylindrical portion 12, and the sliding portion 14 are the same as those of the seal unit 10.

[0106] However, bellows portion 113 has more inclined portions and bent portions than bellows portion 13. That is, bellows portion 113 has inclined portion 20, bent portion 121, inclined portion 122, bent portion 123, inclined portion 124, bent portion 125, inclined portion 126, bent portion 127, inclined portion 128, bent portion 129, and inclined portion 130. Inclined portions 20, 122, 124, 126, 128, and 130 have a truncated cone shape. However, the inclination directions of inclined portions 20, 124, and 128 are opposite to the inclination directions of inclined portions 122, 126, and 130.

[0107] Inclined portion 20 is the same as inclined portion 20 in Figures 1 to 3, and bent portion 121 corresponds to bent portion 21 in Figures 1 to 3. Inclined portion 122 corresponds to inclined portion 22 in Figures 1 to 3, and bent portion 123 corresponds to bent portion 23 in Figures 1 to 3. Inclined portion 124 corresponds to inclined portion 24 in Figures 1 to 3.

[0108] The bent portion 125 has a bent (arcuate) cross-sectional shape, and connects the passenger compartment side end edge of the inclined portion 124 and the passenger compartment side end edge of the inclined portion 126 .

[0109] The inclined portion 126 extends from the bent portion 125 toward the engine compartment side. The area of ​​the circular region enclosed by the edge of the inclined portion 126 on the engine compartment side is larger than the area of ​​the circular region enclosed by the edge of the inclined portion 126 connected to the bent portion 125 on the passenger compartment side.

[0110] The bent portion 127 has a bent (arcuate) cross-sectional shape, and connects the engine room side edge of the inclined portion 126 and the engine room side edge of the inclined portion 128 .

[0111] The inclined portion 128 extends from the bent portion 127 toward the passenger compartment side. The area of ​​the circular region enclosed by the edge of the inclined portion 128 on the passenger compartment side is larger than the area of ​​the circular region enclosed by the edge of the inclined portion 128 connected to the bent portion 127 on the engine compartment side.

[0112] The bent portion 129 has a bent (arcuate) cross-sectional shape, and connects the passenger compartment side end edge of the inclined portion 128 and the passenger compartment side end edge of the inclined portion 130 .

[0113] The inclined portion 130 extends from the bent portion 129 toward the engine compartment side and is connected to the elastic ring 15 of the mounting portion 11. The area of ​​the circular region surrounded by the engine compartment side edge of the inclined portion 130 connected to the elastic ring 15 is larger than the area of ​​the circular region surrounded by the passenger compartment side edge of the inclined portion 130 connected to the bent portion 129.

[0114] Slope portion 122 is disposed radially outward of slope portion 20, slope portion 124 is disposed radially outward of slope portion 122, and slope portion 126 is disposed radially outward of slope portion 124. Slope portion 128 is disposed radially outward of slope portion 126, and slope portion 130 is disposed radially outward of slope portion 128. Thus, slope portion 122 is an inner slope portion relative to slope portion 124, and slope portion 124 is an outer slope portion relative to slope portion 122. Slope portion 124 is an inner slope portion relative to slope portion 126, and slope portion 126 is an outer slope portion relative to slope portion 124. Slope portion 126 is an inner slope portion relative to slope portion 128, and slope portion 128 is an outer slope portion relative to slope portion 126.

[0115] The bent portions 121, 123, 125, 127, and 129 have small thicknesses. The bent portions 123, 125, 127, and 129 each have an arc-shaped cross section and a uniform thickness. The thickness of the bent portion 121 is not uniform, and the bent portion 121 has a minimum thickness at a position adjacent to the inclined portion 122.

[0116] Although not shown in Figure 6, the inclined portion 122 has portions corresponding to the inner thin portion 35, the inner thickness varying portion 36, the inner thick portion 37, and the inner thickness varying portion 38, similar to the inclined portion 22 in Figures 1 to 3. One surface of the inclined portion 122 (the surface facing the engine compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 122 (the surface facing the passenger compartment) has a protruding portion due to the change in thickness of the inclined portion 122. A protruding portion may be formed not only on the surface of the inclined portion 122 facing the passenger compartment, but also on the surface of the inclined portion 122 facing the engine compartment.

[0117] 1 to 3, the inclined portion 124 has portions corresponding to the outer thin portion 30, the outer thickness changing portion 31, the outer thick portion 32, the outer thickness changing portion 33, and the outer thin portion 34. One surface of the inclined portion 124 (the surface facing the engine compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 124 (the surface facing the passenger compartment) has a protruding portion due to the change in thickness of the inclined portion 124. A protruding portion may be formed not only on the surface of the inclined portion 124 facing the passenger compartment, but also on the surface of the inclined portion 124 facing the engine compartment.

[0118] 1 to 3, the inclined portion 126 also has portions corresponding to the inner thin portion 35, the inner thickness varying portion 36, the inner thick portion 37, and the inner thickness varying portion 38. One surface of the inclined portion 126 (the surface facing the engine compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 126 (the surface facing the passenger compartment) has a protruding portion due to the change in thickness of the inclined portion 126. A protruding portion may be formed not only on the surface of the inclined portion 126 facing the passenger compartment, but also on the surface of the inclined portion 126 facing the engine compartment.

[0119] 1 to 3, the inclined portion 128 also has portions corresponding to the outer thin portion 30, the outer thickness changing portion 31, the outer thick portion 32, the outer thickness changing portion 33, and the outer thin portion 34. One surface of the inclined portion 128 (the surface facing the engine compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 128 (the surface facing the passenger compartment) has a protruding portion due to the change in thickness of the inclined portion 128. A protruding portion may be formed not only on the surface of the inclined portion 128 facing the passenger compartment, but also on the surface of the inclined portion 128 facing the engine compartment.

[0120] In the first seal portion 10A, the inclined portions 122, 124, 126, and 128 of the bellows portion 113 are provided with thick portions, which effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, the thin portions of the bent portions 123, 125, and 127 and the inclined portions 122, 124, 126, and 128 of the bellows portion 13 are thin and easily deformed, thereby reducing the resistance, i.e., torque, that the seal portion 10A applies to the rotating shaft 4. Even if the elastomer forming the bellows portion 113 hardens, these thin portions are easily deformed, especially in low-temperature environments. Because the resistance applied to the rotating shaft 4 is small, noise generated by sliding between the rotating shaft 4 and the sliding portion 14 is also reduced.

[0121] Preferably, the thickness of the thick portions of the inclined portions 122, 124, 126, and 128 is 1.1 times or more the thickness of the bent portions 123, 125, and 127. In this case, the thick portions of the inclined portions 122, 124, 126, and 128 effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Furthermore, because the bent portions 123, 125, and 127 are thin, the resistance, i.e., torque, that the seal portion 10A applies to the rotating shaft 4 can be reduced. More preferably, the thickness of the thick portions of the inclined portions 122, 124, 126, and 128 is 1.3 times or more the thickness of the bent portions 123, 125, and 127.

[0122] Preferably, the length of the thick portion in each of the inclined portions 124, 128 is greater than 1 / 10.6 of the length of the inclined portion having a truncated cone shape. In this case, since the length of the thick portion having a large thickness in the inclined portions 124, 128 having a truncated cone shape is long, the weight of the inclined portions 124, 128 is large, and the inclined portions 124, 128 effectively suppress the transmission of noise from the engine compartment to the passenger compartment.

[0123] Preferably, the length of the thick portion in each of the inclined portions 122, 126 is greater than 1 / 5.3 of the length of the inclined portion having a truncated cone shape. In this case, since the length of the thick portion having a large thickness in the inclined portions 122, 126 having a truncated cone shape is long, the weight of the inclined portions 122, 126 is large, and the inclined portions 122, 126 effectively suppress the transmission of noise from the engine compartment to the passenger compartment.

[0124] Furthermore, for the inclined portion 122, the bent portion 121 is an inner connecting portion that connects the cylindrical portion 12 and the inclined portion 122. The bent portion (inner connecting portion) 121 has a thickness that is smaller than the thickness of the thick portions of the inclined portions 122, 124, 126, and 128. Therefore, the bent portion 121 having a small thickness is easily deformed, and the resistance, i.e., torque, that the seal portion 10A applies to the rotating shaft 4 can be further reduced.

[0125] Furthermore, for inclined portion 128, bent portion 129 and inclined portion 130 are outer connection portions that connect mounting portion 11 and inclined portion 128. The thickness of bent portion (outer connection portion) 129 and the thickness of inclined portion (outer connection portion) 130 are smaller than the thickness of the thick portions of inclined portions 122, 124, 126, and 128. Therefore, bent portion 129 and inclined portion 130, which have small thicknesses, are more likely to deform, and the resistance, i.e., torque, that seal portion 10A applies to rotating shaft 4 can be further reduced.

[0126] Preferably, the thickness of the thick portion of the inclined portion 128 is 1.1 times or more the thickness of the bent portion (outer connection portion) 129 and the thickness of the inclined portion (outer connection portion) 130. In this case, the thick portion of the inclined portion 128 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment. On the other hand, because the thicknesses of the bent portion (outer connection portion) 129 and the inclined portion (outer connection portion) 130 are small, the resistance, i.e., torque, that the sealing device 10A applies to the rotating shaft 4 can be reduced.

[0127] Each of the inclined portions 122, 124, 126, and 128 has a thickness change portion where the thickness gradually changes. Therefore, stress concentration is unlikely to occur in the inclined portions 122, 124, 126, and 128. Furthermore, when the bellows portion 113 is manufactured using a mold, the thickness change portion where the thickness gradually changes does not hinder the flow of the elastomer in the cavity inside the mold, so the elastomer can easily spread throughout the inside of the mold that molds the bellows portion 113.

[0128] Although each of the inclined portions 122, 124, 126, and 128 has a thickness change portion where the thickness gradually changes, the bellows portion 113 does not have an undercut that would prevent the bellows portion 113 from being axially separated from the mold that molded the bellows portion 113. Therefore, when the bellows portion 113 is manufactured using a mold, the bellows portion 113 is easily removed from the mold.

[0129] Similar to the seal unit 50, the second seal unit (second sealing device) 50A has an annular mounting portion 51, a cylindrical portion 52 arranged radially inside the mounting portion 51, and a bent bellows portion 153 interposed between the mounting portion 51 and the cylindrical portion 52 to connect them. The cylindrical portion 52 and the bellows portion 153 are formed from the same elastomer as the elastic ring 55 of the mounting portion 51. Preferably, the elastic ring 55, the cylindrical portion 52, and the bellows portion 153 are formed integrally. Furthermore, the seal unit 50 has a sliding portion 54 arranged radially inside the cylindrical portion 52 and in slidable contact with the outer peripheral surface of the rotating shaft 4.

[0130] However, bellows portion 153 has more inclined portions and bent portions than bellows portion 53. That is, bellows portion 153 has inclined portion 162, bent portion 163, inclined portion 164, bent portion 165, inclined portion 166, bent portion 167, inclined portion 168, and bent portion 169. Inclined portions 162, 164, 166, and 168 have a truncated cone shape. However, the inclination direction of inclined portions 162 and 166 is opposite to the inclination direction of inclined portions 164 and 168.

[0131] 1 to 3. The bent portion 61 has a bent cross-sectional shape, and connects the end edge of the cylindrical portion 52 on the passenger compartment side and the end edge of the inclined portion 162 on the passenger compartment side.

[0132] The inclined portion 162 corresponds to the inclined portion 62 in Figures 1 to 3, and the bent portion 163 corresponds to the bent portion 63 in Figures 1 to 3. The inclined portion 164 corresponds to the inclined portion 64 in Figures 1 to 3.

[0133] The bent portion 165 has a bent (arcuate) cross-sectional shape, and connects the passenger compartment side end edge of the inclined portion 164 and the passenger compartment side end edge of the inclined portion 166 .

[0134] The inclined portion 166 extends from the bent portion 165 toward the engine compartment side. The area of ​​the circular region enclosed by the edge of the inclined portion 166 on the engine compartment side is larger than the area of ​​the circular region enclosed by the edge of the inclined portion 166 connected to the bent portion 165 on the passenger compartment side.

[0135] The bent portion 167 has a bent (arcuate) cross-sectional shape, and connects the engine room side edge of the inclined portion 166 and the engine room side edge of the inclined portion 168 .

[0136] The inclined portion 168 extends from the bent portion 167 toward the passenger compartment side. The area of ​​the circular region enclosed by the edge of the inclined portion 168 on the passenger compartment side is larger than the area of ​​the circular region enclosed by the edge of the inclined portion 168 connected to the bent portion 167 on the engine compartment side.

[0137] The bent portion 169 has a bent cross-sectional shape and connects the passenger compartment side edge of the inclined portion 168 to the elastic ring 55 of the mounting portion 51. The inner flange 56b (see FIG. 1) of the rigid ring 56 of the mounting portion 51 is embedded in the bent portion 169.

[0138] Thus, inclined portion 164 is disposed radially outward of inclined portion 162, inclined portion 166 is disposed radially outward of inclined portion 164, and inclined portion 168 is disposed radially outward of inclined portion 166. Therefore, inclined portion 164 is the outer inclined portion of inclined portion 162, and inclined portion 162 is the inner inclined portion of inclined portion 164. Inclined portion 166 is the outer inclined portion of inclined portion 164, and inclined portion 164 is the inner inclined portion of inclined portion 166. Inclined portion 168 is the outer inclined portion of inclined portion 166, and inclined portion 166 is the inner inclined portion of inclined portion 168.

[0139] In the second seal portion 50A, the portion formed by the inclined portion 162, the bent portion 163, and the inclined portion 164 is convex toward the engine compartment. Similarly, in the first seal portion 10A, the portion formed by the inclined portion 122, the bent portion 123, and the inclined portion 124 is also convex toward the engine compartment. In the second seal portion 50A, the portion formed by the inclined portion 164, the bent portion 165, and the inclined portion 166 is convex toward the passenger compartment. Similarly, in the first seal portion 10A, the portion formed by the inclined portion 124, the bent portion 125, and the inclined portion 126 is also convex toward the passenger compartment. In the second seal portion 50A, the portion formed by the inclined portion 166, the bent portion 167, and the inclined portion 168 is convex toward the engine compartment. Similarly, in the first seal portion 10A, the portion formed by the inclined portion 126, the bent portion 127, and the inclined portion 128 is also convex toward the engine compartment.

[0140] The bent portions 61, 163, 165, 167, and 169 have small thicknesses. The bent portions 163, 165, and 167 each have an arc-shaped cross section and a uniform thickness. The thickness of the bent portion 169 is not uniform, with the bent portion 169 having a minimum thickness at a position adjacent to the inclined portion 168. The thickness of the bent portion 61 is also not uniform, with the bent portion 61 having a minimum thickness at a position adjacent to the inclined portion 162.

[0141] Although not shown in Figure 6, the inclined portion 162 has portions corresponding to the inner thin portion 75, the inner thickness varying portion 76, the inner thick portion 77, and the inner thickness varying portion 78, similar to the inclined portion (inner inclined portion) 62 in Figures 1 to 3. One surface of the inclined portion 162 (the surface facing the passenger compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 162 (the surface facing the engine compartment) has a protruding portion due to the change in thickness of the inclined portion 162. A protruding portion may be formed not only on the surface of the inclined portion 162 facing the engine compartment, but also on the surface of the inclined portion 162 facing the passenger compartment.

[0142] 1 to 3, the inclined portion 164 has portions corresponding to the outer thin portion 70, the outer thickness change portion 71, the outer thick portion 72, and the outer thickness change portion 73. One surface of the inclined portion 164 (the surface facing the passenger compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 164 (the surface facing the engine compartment) has a protruding portion due to the change in thickness of the inclined portion 164. A protruding portion may be formed not only on the surface of the inclined portion 164 facing the engine compartment, but also on the surface of the inclined portion 164 facing the passenger compartment.

[0143] 1 to 3, the inclined portion 166 also has portions corresponding to the inner thin portion 75, the inner thickness varying portion 76, the inner thick portion 77, and the inner thickness varying portion 78. One surface of the inclined portion 166 (the surface facing the passenger compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 166 (the surface facing the engine compartment) has a protruding portion due to the change in thickness of the inclined portion 166. A protruding portion may be formed not only on the surface of the inclined portion 166 facing the engine compartment, but also on the surface of the inclined portion 166 facing the passenger compartment.

[0144] 1 to 3, the inclined portion 168 also has portions corresponding to the outer thin portion 70, the outer thickness changing portion 71, the outer thick portion 72, and the outer thickness changing portion 73. One surface of the inclined portion 168 (the surface facing the passenger compartment) has a smooth truncated cone shape. However, the other surface of the inclined portion 168 (the surface facing the engine compartment) has a protruding portion due to the change in thickness of the inclined portion 168. A protruding portion may be formed not only on the surface of the inclined portion 168 facing the engine compartment, but also on the surface of the inclined portion 168 facing the passenger compartment.

[0145] In the second seal portion 50A, the inclined portions 162, 164, 166, and 168 of the bellows portion 153 are provided with thick portions, which effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, the thin portions of the bent portions 163, 165, and 167 and the inclined portions 162, 164, 166, and 168 of the bellows portion 153 are thin and easily deformed, thereby reducing the resistance, i.e., torque, that the seal portion 50A applies to the rotating shaft 4. Even if the elastomer forming the bellows portion 153 hardens, these thin portions are easily deformed, especially in low-temperature environments. Because the resistance applied to the rotating shaft 4 is small, noise generated by sliding between the rotating shaft 4 and the sliding portion 54 is also reduced.

[0146] Preferably, the thickness of the thick portions of the inclined portions 162, 164, 166, and 168 is 1.1 times or more the thickness of the bent portions 163, 165, and 167. In this case, the thick portions of the inclined portions 162, 164, 166, and 168 effectively suppress the transmission of noise from the engine compartment to the passenger compartment. Furthermore, because the bent portions 163, 165, and 167 are thin, the resistance, i.e., torque, that the seal portion 50A applies to the rotating shaft 4 can be reduced. More preferably, the thick portions of the inclined portions 162, 164, 166, and 168 are 1.3 times or more the thickness of the bent portions 163, 165, and 167.

[0147] Preferably, the length of the thick portion in each of the inclined portions 164, 168 is greater than 1 / 3.2 of the length of the inclined portion having a truncated cone shape. In this case, since the length of the thick portion having a large thickness in the inclined portions 164, 168 having a truncated cone shape is long, the weight of the inclined portions 164, 168 is large, and the inclined portions 164, 168 effectively suppress the transmission of noise from the engine compartment to the passenger compartment.

[0148] Preferably, the length of the thick portion in each of the inclined portions 162, 166 is greater than 1 / 3.8 of the length of the inclined portion having a truncated cone shape. In this case, since the length of the thick portion having a large thickness in the inclined portions 162, 166 having a truncated cone shape is long, the weight of the inclined portions 162, 166 is large, and the inclined portions 162, 166 effectively suppress the transmission of noise from the engine compartment to the passenger compartment.

[0149] Furthermore, for inclined portion 162, bent portion 61 is an inner connecting portion that connects cylindrical portion 52 and inner inclined portion 162. Bent portion (inner connecting portion) 61 has a thickness that is smaller than the thickness of the thick portions of inclined portions 162, 164, 166, and 168. Therefore, bent portion 61 with a small thickness is more likely to deform, and therefore the resistance, i.e., torque, that seal portion 50A applies to rotating shaft 4 can be further reduced.

[0150] Preferably, the thickness of the thick portion of the inclined portion 162 is at least 1.1 times the maximum thickness of the bent portion (inner connection portion) 61. In this case, the thick portion of the inclined portion 162 effectively suppresses the transmission of noise from the engine compartment to the passenger compartment. In addition, because the bent portion 61 is thin, the resistance, i.e., torque, that the seal portion 10A applies to the rotating shaft 4 can be reduced.

[0151] Furthermore, for the inclined portion 168, the bent portion 169 is an outer connecting portion that connects the mounting portion 51 and the outer inclined portion 168. The thickness of the bent portion (outer connecting portion) 169 is smaller than the thickness of the thick portions of the inclined portions 162, 164, 166, and 168. Therefore, the bent portion 169 having a small thickness is more likely to deform, and the resistance, i.e., torque, that the seal portion 50A applies to the rotating shaft 4 can be further reduced.

[0152] Each of inclined portions 162, 164, 166, and 168 has a thickness change portion where the thickness gradually changes. Therefore, stress concentration is unlikely to occur in inclined portions 162, 164, 166, and 168. Furthermore, when bellows portion 153 is manufactured using a mold, the thickness change portion where the thickness gradually changes does not hinder the flow of elastomer in the cavity inside the mold, so the elastomer can easily spread throughout the inside of the mold that molds bellows portion 153.

[0153] Although each of the inclined portions 162, 164, 166, and 168 has a thickness change portion where the thickness gradually changes, the bellows portion 153 does not have an undercut that would prevent the bellows portion 153 from being axially separated from the mold that molded the bellows portion 153. Therefore, when the bellows portion 153 is manufactured using a mold, the bellows portion 153 can be easily removed from the mold.

[0154] As described above, the sealing device 1A according to this embodiment has two seal portions 10A, 50A having similar structures. The double structure having the seal portions 10A, 50A further improves the function of suppressing sound transmission from the engine compartment space E to the passenger compartment space P, and further improves the function of suppressing the intrusion of foreign matter from the engine compartment space E to the passenger compartment space P.

[0155] The number of slopes and bends in each bellows section may be greater, and the number of slopes and bends in the bellows section of the first seal section may be different from the number of slopes and bends in the bellows section of the second seal section.

[0156] When the seal portions 10A, 50A are not elastically deformed, the bent portion 61 of the second seal portion 50A overlaps the bent portion 121 of the first seal portion 10A in the axial direction, and the inclined portion 162 overlaps the inclined portion 122 in the axial direction. Also, at this time, the bent portion 163 overlaps the bent portion 123 in the axial direction, and the inclined portion 164 overlaps the inclined portion 124 in the axial direction. The bent portion 165 overlaps the bent portion 125 in the axial direction, and the inclined portion 166 overlaps the inclined portion 126 in the axial direction. The bent portion 167 overlaps the bent portion 127 in the axial direction, the inclined portion 168 overlaps the inclined portion 128 in the axial direction, and the bent portion 169 overlaps the bent portion 129 in the axial direction.

[0157] In such a double structure having seal portions 10A and 50A, it is desirable that bellows portion 113 of seal portion 10A and bellows portion 153 of seal portion 50A do not collide with each other when rotating shaft 4 is inclined and eccentric with respect to hole 2A. In the illustrated embodiment, bellows portion 113 and bellows portion 153 are sufficiently separated from each other in the axial direction, but in an embodiment in which bellows portion 113 and bellows portion 153 are close to each other in the axial direction, it is particularly desirable that the thick portion of bellows portion 113 does not collide with the thick portion of bellows portion 153.

[0158] Therefore, the thick portions of each of the inclined portions 122, 124, 126, and 128 of the first seal portion 10A protrude toward the opposite side (passenger compartment side) of the bellows portion 53 of the second seal portion 50 relative to the truncated cone shape of the inclined portion, and the surface of each of the inclined portions 122, 124, 126, and 128 facing the bellows portion 53 of the second seal portion 50 (the surface on the engine compartment side) has a smooth truncated cone shape.

[0159] On the other hand, the thick portions of each of the inclined portions 162, 164, 166, and 168 of the second seal portion 50A protrude toward the opposite side (engine compartment side) of the bellows portion 13 of the first seal portion 10 relative to the truncated cone shape of the inclined portion, and the surface of each of the inclined portions 162, 164, 166, and 168 facing the bellows portion 13 of the first seal portion 10 (the surface facing the crew compartment) has a smooth truncated cone shape.

[0160] Therefore, even if the axial distance between the bellows portion 113 of the first seal portion 10A and the bellows portion 153 of the second seal portion 50A is small, the inclined portions 122, 124, 126, and 128 (especially the thick portions) of the first seal portion 10A are unlikely to collide with the inclined portions 162, 164, 166, and 168 (especially the thick portions) of the second seal portion 50.

[0161] Although the present invention has been shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that changes may be made in form and detail without departing from the scope of the invention as set forth in the appended claims. Such changes, modifications and alterations are intended to be included within the scope of the invention.

[0162] For example, a known sound-proof ring as disclosed in Japanese Patent Application Laid-Open No. 2016-20721 or Japanese Patent Application Laid-Open No. 2019-7552 may be provided around the rotating shaft 4.

[0163] In the above embodiment, the sealing device 1 is a steering dust seal, but the present invention is not limited to steering dust seals and can be applied to sealing devices that seal the periphery of a rotating shaft that can be significantly eccentric and attenuate noise.

[0164] Aspects of the present invention are also described in the following numbered clauses: Clause 1. A sealing device for sealing a gap between an outer support member and a rotating shaft disposed in a hole provided in the outer support member, the sealing device comprising: an annular mounting portion attached to the hole of the outer support member, a cylindrical portion disposed radially inside the mounting portion, a sliding portion disposed radially inside the cylindrical portion and in slidable contact with an outer peripheral surface of the rotating shaft, and an elastomer bellows portion interposed between the mounting portion and the cylindrical portion, the bellows portion having an outer inclined portion having a truncated cone shape, an inner inclined portion having a truncated cone shape inclined in the opposite direction to the outer inclined portion, and a bent portion having a bent cross-sectional shape connecting the outer inclined portion and the inner inclined portion, the outer inclined portion having an outer thick portion having a thickness greater than a thickness of the bent portion, and the inner inclined portion having an inner thick portion having a thickness greater than a thickness of the bent portion.

[0165] Clause 2. The sealing device according to Clause 1, wherein the outer inclined portion further comprises an outer thin portion connected to the bent portion and having the same thickness as the bent portion, a first outer thickness change portion connecting the outer thin portion and the outer thick portion and having a thickness that linearly increases from the outer thin portion toward the outer thick portion, and a second outer thickness change portion between the outer thick portion and the mounting portion and having a thickness that linearly decreases from the outer thick portion, the outer thick portion having a uniform thickness, and the inner inclined portion further comprises an inner thin portion connected to the bent portion and having the same thickness as the bent portion, a first inner thickness change portion connecting the inner thin portion and the inner thick portion and having a thickness that linearly increases from the inner thin portion toward the inner thick portion, and a second inner thickness change portion between the inner thick portion and the cylindrical portion and having a thickness that linearly decreases from the inner thick portion, the inner thick portion having a uniform thickness. The outer and inner inclined portions have portions where the thickness gradually changes, which reduces stress concentration. Furthermore, when manufacturing the bellows using a mold, for example, the portions where the thickness gradually changes do not hinder the flow of the elastomer inside the mold, which makes it easier for the elastomer to spread throughout the mold used to form the bellows.

[0166] Clause 3. The sealing device of Clause 2, wherein the bellows portion does not have an undercut that would prevent the bellows portion from being axially separated from a mold that molds the bellows portion. The outer and inner sloped portions have portions where the thickness gradually changes, but when the bellows portion is manufactured using a mold, the bellows portion is easily removed from the mold.

[0167] Clause 4. The sealing device according to Clause 3, wherein the outer thickened portion of the outer inclined portion protrudes radially outward relative to the truncated cone shape of the outer inclined portion, the outer peripheral surface of the second outer thickness change portion of the outer inclined portion is substantially cylindrical, the inner thickened portion of the inner inclined portion protrudes radially inward relative to the truncated cone shape of the inner inclined portion, and the inner peripheral surface of the second inner thickness change portion of the inner inclined portion is substantially cylindrical. With the above configuration, the bellows portion does not have an undercut that would prevent the bellows portion from being removed from a mold that molds the bellows portion.

[0168] Clause 5. The sealing device according to Clause 3, wherein the outer thickened portion of the outer inclined portion protrudes radially inward relative to the truncated cone shape of the outer inclined portion, the inner peripheral surface of the first outer thickness change portion of the outer inclined portion is substantially cylindrical, the inner thickened portion of the inner inclined portion protrudes radially outward relative to the truncated cone shape of the inner inclined portion, and the outer peripheral surface of the first inner thickness change portion of the inner inclined portion is substantially cylindrical. With the above configuration, the bellows portion does not have an undercut that would prevent the bellows portion from being removed from a mold that molds the bellows portion.

[0169] Clause 6. The sealing device according to any one of Clauses 2 to 5, wherein the length of the outer thick portion is greater than 1 / 10.6 of the length of the outer inclined portion having a truncated cone shape including the outer thin portion, the first outer thickness change portion, the outer thick portion, and the second outer thickness change portion, and the length of the inner thick portion is greater than 1 / 5.3 of the length of the inner inclined portion having a truncated cone shape including the inner thin portion, the first inner thickness change portion, the inner thick portion, and the second inner thickness change portion. In this case, since the outer thick portion having a truncated cone shape is long and thick, the weight of the outer inclined portion is large, and the outer inclined portion effectively suppresses the transmission of noise from the engine compartment to the passenger compartment. Furthermore, since the inner thick portion having a truncated cone shape is long and thick, the weight of the inner inclined portion is large, and the inner inclined portion effectively suppresses the transmission of noise from the engine compartment to the passenger compartment.

[0170] Clause 7. The sealing device according to any one of Clauses 2 to 6, wherein the thickness of the outer thick portion is 1.1 times or more the thickness of the bent portion, and the thickness of the inner thick portion is 1.1 times or more the thickness of the bent portion. Because the thicknesses of the outer thick portion and the inner thick portion are 1.1 times or more the thickness of the bent portion, the outer thick portion and the inner thick portion effectively suppress the transmission of noise from the engine compartment to the passenger compartment. On the other hand, because the thickness of the bent portion is 1 / 1.1 or less the thickness of the outer thick portion and the inner thick portion, the resistance, i.e., torque, that the sealing device applies to the rotating shaft can be reduced.

[0171] Clause 8. The sealing device according to any one of Clauses 1 to 7, further comprising an inner connecting portion that connects the cylindrical portion and the inner inclined portion of the bellows portion, the inner connecting portion having a thickness smaller than the thickness of the outer thick-walled portion and the thickness of the inner thick-walled portion. In this case, the inner connecting portion having a small thickness is more likely to deform, and therefore the resistance, i.e., torque, that the sealing device applies to the rotating shaft can be further reduced.

[0172] Clause 9. The sealing device according to Clause 8, wherein the thickness of the inner thick portion is 1.1 times or more the thickness of the inner connecting portion. Since the thickness of the inner thick portion is 1.1 times or more the thickness of the inner connecting portion, the inner thick portion effectively suppresses the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, since the thickness of the inner connecting portion is 1 / 1.1 or less the thickness of the inner thick portion, the resistance, i.e., torque, that the sealing device applies to the rotating shaft can be reduced.

[0173] Clause 10. The sealing device according to any one of Clauses 1 to 9, further comprising an outer connecting portion that connects the mounting portion and the outer inclined portion of the bellows portion, the outer connecting portion having a thickness that is smaller than the thickness of the outer thick portion and the thickness of the inner thick portion. In this case, the outer connecting portion having a smaller thickness is more likely to deform, and therefore the resistance, i.e., torque, that the sealing device applies to the rotating shaft can be further reduced.

[0174] Clause 11. The sealing device according to Clause 10, wherein the thickness of the outer thick portion is 1.1 times or more the thickness of the outer connecting portion. Since the thickness of the outer thick portion is 1.1 times or more the thickness of the outer connecting portion, the outer thick portion effectively suppresses the transmission of noise from the engine compartment to the passenger compartment. Meanwhile, since the thickness of the outer connecting portion is 1 / 1.1 or less the thickness of the outer thick portion, the resistance, i.e., torque, that the sealing device applies to the rotating shaft can be reduced.

[0175] Clause 12. the rotating shaft includes a first seal portion and a second seal portion, each of the first seal portion and the second seal portion having an annular mounting portion attached to the hole of the outer support member, a cylindrical portion arranged radially inside the mounting portion, a sliding portion arranged radially inside the cylindrical portion and in slidable contact with the outer peripheral surface of the rotating shaft, and an elastomer bellows portion interposed between the mounting portion and the cylindrical portion, the bellows portion having an outer inclined portion having a truncated cone shape, an inner inclined portion having a truncated cone shape inclined in the opposite direction to the outer inclined portion, and a bent portion having a bent cross-sectional shape connecting the outer inclined portion and the inner inclined portion, the outer inclined portion having a thick outer portion having a thickness greater than a thickness of the bent portion, the inner inclined portion having a thickness greater than a thickness of the bent portion, the bent portion, the outer inclined portion, and the inner inclined portion of the first seal portion overlap the bent portion, the outer inclined portion, and the inner inclined portion of the second seal portion, respectively, in the axial direction, The outer thick portion of the outer inclined portion of the first seal portion protrudes toward the opposite side of the bellows portion of the second seal portion relative to the truncated cone shape of the outer inclined portion, a surface of the outer inclined portion of the first seal portion facing the bellows portion of the second seal portion has a smooth truncated cone shape, the inner thick portion of the inner inclined portion of the first seal portion protrudes toward the opposite side of the bellows portion of the second seal portion relative to the truncated cone shape of the inner inclined portion, a surface of the inner inclined portion of the first seal portion facing the bellows portion of the second seal portion has a smooth truncated cone shape, the outer thick portion of the outer inclined portion of the second seal portion protrudes toward the opposite side of the bellows portion of the first seal portion relative to the truncated cone shape of the outer inclined portion, and a surface of the outer inclined portion of the second seal portion facing the bellows portion of the first seal portion has a smooth truncated cone shape, Clause 12. The sealing device according to any one of clauses 1 to 11, wherein the inner thick portion of the inner inclined portion of the second seal portion protrudes toward the opposite side of the bellows portion of the first seal portion relative to the truncated cone shape of the inner inclined portion, and the surface of the inner inclined portion of the second seal portion facing the bellows portion of the first seal portion has a smooth truncated cone shape.In this case, the bent portion, outer inclined portion, and inner inclined portion of the first seal portion overlap in the axial direction with the bent portion, outer inclined portion, and inner inclined portion of the second seal portion, respectively. The inclined portions have thick portions. However, because the shapes of the outer inclined portion and inner inclined portion of the first seal portion and the outer inclined portion and inner inclined portion of the second seal portion are as described above, even if the axial distance between the bellows portion of the first seal portion and the bellows portion of the second seal portion is small, the outer inclined portion of the first seal portion is unlikely to collide with the outer inclined portion of the second seal portion, and the inner inclined portion of the first seal portion is unlikely to collide with the inner inclined portion of the second seal portion.

[0176] E Space on the engine compartment side P Space on the passenger compartment side 1, 1A Sealing device (steering dust seal) 2 Outer support member 2A Hole 4 Rotating shaft (steering shaft) 10, 10A First seal portion (first sealing device) 50, 50A Second seal portion (second sealing device) 11, 51 Mounting portion 12, 52 Cylindrical portion 13, 53, 113, 153 Bellows portion 14, 54 Sliding portion 20 Inclined portion 21, 61, 121 Bent portion (inner connection portion) 22, 62 Inclined portion (inner inclined portion) 23, 63, 123, 125, 127, 163, 165, 167 Bent portion 24, 64 Inclined portion (outer inclined portion) 122, 124, 126, 162, 164, 166 Inclined portion (inner inclined portion) 124, 126, 128, 164, 166, 168 Inclined portion (outer inclined portion) 25, 65, 129, 169 Bent portion (outer connecting portion) 26, 130 Inclined portion (outer connecting portion) 30, 70 Outer thin portion 31, 71 Outer thickness change portion (first outer thickness change portion) 32, 72 Outer thick portion 33, 73 Outer thickness change portion (second outer thickness change portion) 34 Outer thin portion 35, 75 Inner thin portion 36, 76 Inner thickness change portion (first inner thickness change portion) 37, 77 Inner thick portion 38, 78 Inner thickness change portion (second inner thickness change portion) 80, 81, 90, 91 Type

Claims

1. A sealing device for sealing a gap between an outer support member and a rotating shaft disposed in a hole provided in the outer support member, comprising: an annular mounting portion attached to the hole of the outer support member; a cylindrical portion disposed radially inside the mounting portion; a sliding portion disposed radially inside the cylindrical portion and in slidable contact with the outer peripheral surface of the rotating shaft; and an elastomer bellows portion interposed between the mounting portion and the cylindrical portion, wherein the bellows portion has an outer inclined portion having a truncated cone shape, an inner inclined portion having a truncated cone shape inclined in the opposite direction to the outer inclined portion, and a bent portion having a bent cross-sectional shape connecting the outer inclined portion and the inner inclined portion, wherein the outer inclined portion has an outer thick portion having a thickness greater than that of the bent portion, and the inner inclined portion has an inner thick portion having a thickness greater than that of the bent portion.

2. The sealing device according to claim 1, wherein the outer inclined portion further comprises: an outer thin portion connected to the bent portion and having the same thickness as the bent portion; a first outer thickness varying portion connecting the outer thin portion and the outer thick portion and having a thickness that linearly increases from the outer thin portion toward the outer thick portion; and a second outer thickness varying portion located between the outer thick portion and the mounting portion and having a thickness that linearly decreases from the outer thick portion, the outer thick portion having a uniform thickness; and the inner inclined portion further comprises: an inner thin portion connected to the bent portion and having the same thickness as the bent portion; a first inner thickness varying portion connecting the inner thin portion and the inner thick portion and having a thickness that linearly increases from the inner thin portion toward the inner thick portion; and a second inner thickness varying portion located between the inner thick portion and the cylindrical portion and having a thickness that linearly decreases from the inner thick portion, the inner thick portion having a uniform thickness.

3. A sealing device as set forth in claim 2, wherein said bellows portion does not have any undercuts that would prevent said bellows portion from being axially separated from the mold that molded said bellows portion.

4. A sealing device as set forth in claim 3, wherein the outer thick portion of the outer inclined portion protrudes radially outward relative to the truncated cone shape of the outer inclined portion, the outer peripheral surface of the second outer thickness varying portion of the outer inclined portion is approximately cylindrical, the inner thick portion of the inner inclined portion protrudes radially inward relative to the truncated cone shape of the inner inclined portion, and the inner peripheral surface of the second inner thickness varying portion of the inner inclined portion is approximately cylindrical.

5. A sealing device as set forth in claim 3, wherein the outer thick portion of the outer inclined portion protrudes radially inward relative to the truncated cone shape of the outer inclined portion, the inner peripheral surface of the first outer thickness changing portion of the outer inclined portion is approximately cylindrical, the inner thick portion of the inner inclined portion protrudes radially outward relative to the truncated cone shape of the inner inclined portion, and the outer peripheral surface of the first inner thickness changing portion of the inner inclined portion is approximately cylindrical.

6. A sealing device according to any one of claims 2 to 5, wherein the length of the outer thick portion is greater than 1 / 10.6 of the length of the outer inclined portion having a truncated cone shape including the outer thin portion, the first outer thickness change portion, the outer thick portion, and the second outer thickness change portion, and the length of the inner thick portion is greater than 1 / 5.3 of the length of the inner inclined portion having a truncated cone shape including the inner thin portion, the first inner thickness change portion, the inner thick portion, and the second inner thickness change portion.

7. A sealing device according to any one of claims 2 to 6, wherein the thickness of the outer thick portion is 1.1 times or more the thickness of the bent portion, and the thickness of the inner thick portion is 1.1 times or more the thickness of the bent portion.

8. A sealing device according to any one of claims 1 to 7, further comprising an inner connecting portion connecting the cylindrical portion and the inner inclined portion of the bellows portion, the inner connecting portion having a thickness smaller than the thickness of the outer thick portion and the thickness of the inner thick portion.

9. The sealing device according to claim 8, wherein the thickness of the inner thick portion is 1.1 times or more the thickness of the inner connecting portion.

10. A sealing device according to any one of claims 1 to 9, further comprising an outer connecting portion that connects the mounting portion and the outer inclined portion of the bellows portion, the outer connecting portion having a thickness smaller than the thickness of the outer thick portion and the thickness of the inner thick portion.

11. The sealing device according to claim 10, wherein the thickness of the outer thick portion is 1.1 times or more the thickness of the outer connecting portion.

12. A rotary knives comprising a first seal portion and a second seal portion, each of the first seal portion and the second seal portion having an annular mounting portion attached to the hole of the outer support member, a cylindrical portion arranged radially inside the mounting portion, a sliding portion arranged radially inside the cylindrical portion and in slidable contact with the outer peripheral surface of the rotating shaft, and an elastomer bellows portion interposed between the mounting portion and the cylindrical portion, the bellows portion having an outer inclined portion having a truncated cone shape, an inner inclined portion having a truncated cone shape inclined in the opposite direction to the outer inclined portion, and a bent portion having a bent cross-sectional shape connecting the outer inclined portion and the inner inclined portion, the outer inclined portion having an outer thick portion having a thickness greater than that of the bent portion, and the inner inclined portion having an inner thick portion having a thickness greater than that of the bent portion, the bent portion, the outer inclined portion, and the inner inclined portion of the first seal portion overlap with the bent portion, the outer inclined portion, and the inner inclined portion of the second seal portion, respectively, in the axial direction; the outer thick portion of the outer inclined portion of the first seal portion protrudes toward the opposite side of the bellows portion of the second seal portion relative to the truncated cone shape of the outer inclined portion; a surface of the outer inclined portion of the first seal portion facing the bellows portion of the second seal portion has a smooth truncated cone shape; the inner thick portion of the inner inclined portion of the first seal portion protrudes toward the opposite side of the bellows portion of the second seal portion relative to the truncated cone shape of the inner inclined portion; a surface of the inner inclined portion of the first seal portion facing the bellows portion of the second seal portion has a smooth truncated cone shape; and the outer thick portion of the outer inclined portion of the second seal portion protrudes toward the opposite side of the bellows portion of the first seal portion relative to the truncated cone shape of the outer inclined portion.

12. The sealing device according to claim 1, wherein a surface of the outer inclined portion of the second seal portion facing the bellows portion of the first seal portion has a smooth truncated cone shape, the inner thick portion of the inner inclined portion of the second seal portion protrudes toward the opposite side of the bellows portion of the first seal portion relative to the truncated cone shape of the inner inclined portion, and the surface of the inner inclined portion of the second seal portion facing the bellows portion of the first seal portion has a smooth truncated cone shape.

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