JP7570904B2 - Dust cover - Google Patents

Description

This disclosure relates to a dust cover that is placed in the gap between a steering shaft and a dash panel.

The steering shaft of a vehicle passes through a penetration in the dash panel that separates the passenger compartment from the engine room. Since the steering shaft moves when the steering wheel position is adjusted or due to vibrations while driving, a certain gap is provided between the steering shaft and the penetration in the dash panel. However, it is necessary to prevent foreign matter such as dust from entering the passenger compartment. For this reason, a dust cover is provided in the gap between the steering shaft and the penetration in the dash panel (see, for example, Patent Document 1).

JP 2019-6268 A

In the dust cover described in Patent Document 1, a seal lip that prevents dust and other particles from entering the vehicle interior is fixed to the bush by vulcanization adhesion. However, vulcanization adhesion requires a process of applying adhesive to the bush and a molding process of insert-molding the seal lip into the bush, and the vulcanization process takes a long time, making it difficult to manufacture the seal lip.

This disclosure was made in consideration of the above problems, and aims to provide a dust cover that makes it easy to manufacture the sealing member.

In order to achieve the above object, a dust cover according to one embodiment of the present disclosure includes a bush attached to the outer circumferential surface of a steering shaft that passes through a cylindrical member of a dash panel, and an annular bellows that closes the gap between the cylindrical member and the bush, and the bellows has a seal member whose inner end is located more inward than the outer end of the bush and whose passenger compartment end is located more inward than the passenger compartment end of the bush. In this manner, the seal member is integrally provided on the bellows. Therefore, compared to the conventional method of fixing the seal member to the bush by vulcanization adhesion, the present disclosure has the advantage of omitting the adhesive application process and the insert molding process of the seal member, making it easier to manufacture the seal member.

As a preferred embodiment of the dust cover, the inner end of the seal member may be positioned on the outer side of the inner end of the bush. This has the advantage of reducing the occurrence of abnormal noise caused by stick-slip between the inner end of the seal member and the steering shaft. A gap is provided between the inner end of the seal member and the steering shaft, and the size of this gap can be adjusted to prevent dust and other particles from entering the vehicle interior.

As a preferred embodiment of the dust cover, the seal member has a slit extending from the inner peripheral end toward the outer peripheral side, and the inner peripheral end of the seal member may be positioned more inward than the inner peripheral end of the bush. This causes the inner peripheral end of the seal member to contact the outer peripheral surface of the steering shaft. However, since the seal lip has a slit, it has a lower rigidity than a seal lip without a slit. As a result, it is possible to prevent foreign matter such as dust from entering the vehicle cabin, and to suppress the generation of abnormal noise caused by stick-slip between the inner peripheral end of the seal member and the steering shaft.

As a preferred embodiment of the dust cover, the bushing may have a flange protruding toward the outer periphery, and the inner periphery of the seal member may have a contact portion that contacts the flange. This allows the seal member to be supported radially by the flange, making it possible to more reliably maintain the gap between the end of the seal member and the steering shaft.

As a preferred embodiment of the dust cover, the contact portion of the seal member has a groove recessed toward the outer periphery, and the flange of the bush may be fitted into the groove of the contact portion. This makes it possible to keep the axial position of the seal member constant.

This disclosure provides a dust cover that allows easy manufacturing of the sealing member.

FIG. 1 is a schematic diagram of a steering device according to an embodiment. FIG. 2 is a perspective view of the steering device according to the embodiment. FIG. 3 is a cross-sectional view of the dust cover attached to the vehicle. FIG. 4 is a perspective view of the band according to the embodiment. FIG. 5 is a front view of the dust cover according to the embodiment. FIG. 6 is a cross-sectional view taken along line AA in FIG. FIG. 7 is an enlarged cross-sectional view of a portion of FIG. FIG. 8 is an enlarged cross-sectional view of a seal lip according to a first modified example. FIG. 9 is a cross-sectional view of a dust cover according to a second modified example. FIG. 10 is a front view of a dust cover according to a third modified example. FIG. 11 is a cross-sectional view taken along line BB in FIG. FIG. 12 is an enlarged cross-sectional view of a portion of FIG.

The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following modes for carrying out the invention (hereinafter referred to as embodiments). Furthermore, the components in the following embodiments include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

[Embodiment]
Fig. 1 is a schematic diagram of a steering device of an embodiment. Fig. 2 is a perspective view of the steering device of an embodiment. As shown in Fig. 1, the steering device 80 includes a steering wheel 81, a first steering shaft 82, a steering force assist mechanism 83, a first universal joint 84, a second steering shaft 85, and a second universal joint 86, and is joined to a third steering shaft 87. In the drawings and the following description, the front of a vehicle equipped with the steering device 80 is simply referred to as the front FR or the outside OUT of the vehicle, and the rear of the vehicle is simply referred to as the rear RR or the inside IN of the vehicle. The outside OUT of the vehicle is also the engine room side of the vehicle.

As shown in FIG. 1, the first steering shaft 82 includes an input shaft 82a and an output shaft 82b. One end of the input shaft 82a is connected to the steering wheel 81, and the other end of the input shaft 82a is connected to the output shaft 82b. One end of the output shaft 82b is connected to the input shaft 82a, and the other end of the output shaft 82b is connected to the first universal joint 84.

As shown in FIG. 1, the second steering shaft 85 (steering shaft) connects the first universal joint 84 and the second universal joint 86. One end of the second steering shaft 85 is connected to the first universal joint 84, and the other end is connected to the second universal joint 86. One end of the third steering shaft 87 is connected to the second universal joint 86, and the other end of the third steering shaft 87 is connected to the steering gear 88. As shown in FIG. 2, the second steering shaft 85 passes through the dash panel 10. The dash panel 10 is a partition plate that separates the passenger compartment from the engine room.

As shown in FIG. 1, the steering gear 88 includes a pinion 88a and a rack 88b. The pinion 88a is connected to the third steering shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into linear motion by the rack 88b. The rack 88b is connected to a tie rod 89. The angle of the wheels changes as the rack 88b moves.

As shown in FIG. 1, the steering force assist mechanism 83 includes a reduction gear 92 and an electric motor 93. The reduction gear 92 is, for example, a worm reduction gear. The torque generated by the electric motor 93 is transmitted to a worm wheel via a worm inside the reduction gear 92, causing the worm wheel to rotate. The reduction gear 92 increases the torque generated by the electric motor 93 by means of the worm and the worm wheel. The reduction gear 92 then applies an auxiliary steering torque to the output shaft 82b. In other words, the steering device 80 is of a column assist type.

As shown in FIG. 1, the steering device 80 includes an ECU (Electronic Control Unit) 90, a torque sensor 94, and a vehicle speed sensor 95. The electric motor 93, the torque sensor 94, and the vehicle speed sensor 95 are electrically connected to the ECU 90. The torque sensor 94 outputs the steering torque transmitted to the input shaft 82a to the ECU 90 via CAN (Controller Area Network) communication. The vehicle speed sensor 95 detects the traveling speed (vehicle speed) of the vehicle body on which the steering device 80 is mounted. The vehicle speed sensor 95 is provided on the vehicle body, and outputs the vehicle speed to the ECU 90 via CAN communication.

The ECU 90 controls the operation of the electric motor 93. The ECU 90 acquires signals from each of the torque sensor 94 and the vehicle speed sensor 95. When the ignition switch 98 is on, the ECU 90 is supplied with power from a power supply device 99 (e.g., an on-board battery). The ECU 90 calculates an auxiliary steering command value based on the steering torque and the vehicle speed. The ECU 90 adjusts the value of the power supplied to the electric motor 93 based on the auxiliary steering command value. The ECU 90 acquires information on the induced voltage from the electric motor 93 or information output from a resolver or the like provided in the electric motor 93. The force required to operate the steering wheel 81 is reduced by the ECU 90 controlling the electric motor 93.

Figure 3 is a cross-sectional view of a dust cover attached to a vehicle. Figure 4 is a perspective view of a band according to an embodiment. Figure 5 is a front view of a dust cover according to an embodiment. Figure 6 is a cross-sectional view taken along line A-A in Figure 5. Figure 7 is an enlarged cross-sectional view of a portion of Figure 6.

In the following description, the direction along the central axis Z of the second steering shaft 85 is referred to as the axial direction, the direction perpendicular to the axial direction is referred to as the radial direction, and the direction along a circle centered on the central axis Z is referred to as the circumferential direction.

As shown in FIG. 3, the dash panel 10 includes a cylindrical member 101. The inner peripheral surface of the cylindrical member 101 faces the outer peripheral surface of the second steering shaft 85. The second steering shaft 85 may move due to adjustment of the position of the steering wheel 81 or vibrations during driving. For this reason, an annular gap is provided between the inner peripheral surface of the cylindrical member 101 and the outer peripheral surface of the second steering shaft 85. To close this gap, the steering device 80 includes a dust cover 1.

The dust cover 1 is fitted onto the inner peripheral surface of the cylindrical member 101. The dust cover 1 is fixed to the cylindrical member 101 by a band 7 attached to the outer peripheral surface of the cylindrical member 101. The cylindrical member 101 is deformed by being fastened by the band 7. For example, the cylindrical member 101 is formed of a metal. When the cylindrical member 101 is made of a metal, it is preferable that the cylindrical member 101 has a slit 102 along the axial direction as shown in FIG. 3. By having the slit 102, the cylindrical member 101 is easily deformed when fastened by the band 7.

As shown in FIG. 4, the band 7 includes an inner member 71 and an outer member 72. The inner member 71 and the outer member 72 are made of, for example, metal. The outer member 72 overlaps the outer peripheral surface of the inner member 71. The inner member 71 includes a claw 715 protruding from the outer peripheral surface and a gripping portion 711. The outer member 72 includes an elongated hole 720 and a gripping portion 721. The claw 715 is located inside the elongated hole 720. When a force is applied to the gripping portion 711 and the gripping portion 721 in a direction in which they approach each other, the inner diameter of the inner member 71 becomes smaller. When the inner diameter of the inner member 71 reaches a predetermined size, the claw 715 comes into contact with the end of the elongated hole 720. This prevents the inner diameter of the inner member 71 from becoming smaller than the predetermined size. When the inner diameter of the inner member 71 reaches a predetermined size, for example, a stopper protrudes from the inner wall of the elongated hole 720 to position the claw 715. This prevents the inner member 71 and the outer member 72 from moving relative to each other, so the band 7 remains clamped against the tubular member 101.

As shown in Figures 5 and 6, the dust cover 1 includes an attachment member 6, a bellows 2, a bushing 5, and a seal lip 11. The attachment member 6, the bellows 2, the bushing 5, and the seal lip 11 are each formed in an annular shape.

The mounting member 6 is a member that presses the bellows 2 against the cylindrical member 101 shown in FIG. 3. The mounting member 6 is formed of, for example, an aluminum alloy. The mounting member 6 may be formed of a synthetic resin. As shown in FIG. 6, the mounting member 6 includes a main body portion 61 and a flange portion 62. The main body portion 61 is cylindrical and extends in the circumferential direction of the central axis Z of the second steering shaft 85. The main body portion 61 has an outer peripheral surface 611. The outer peripheral surface 611 is a cylindrical surface that extends in the circumferential direction around the central axis Z. The flange portion 62 protrudes from the main body portion 61 toward the radially outward (outer peripheral side). The flange portion 62 is provided with a through hole 621 that penetrates in the axial direction.

The bellows 2 is made of, for example, rubber. The bellows 2 is an annular member that closes the gap between the cylindrical member 101 and the bushing 5. As shown in FIG. 6, the bellows 2 includes a bushing fitting portion 20, a first outer edge portion 22, a first flexible portion 21, a vertical wall portion 222, a retaining member 223, a second outer edge portion 26, a second flexible portion 25, and a seal lip 100.

The bushing fitting portion 20 is located at the radially inner end of the bellows 2. The bushing fitting portion 20 fits into the bushing 5. That is, the bushing fitting portion 20 contacts the outer peripheral surface of the bushing 5.

As shown in FIG. 6, the first outer edge portion 22 of the bellows 2 is in contact with the outer peripheral surface 611 of the main body portion 61 of the mounting member 6. The first flexible portion 21 connects the bush fitting portion 20 and the first outer edge portion 22. In a cross section including the central axis Z, the first flexible portion 21 is approximately U-shaped. A recess 221 recessed radially inward is provided on the outer peripheral surface of the first outer edge portion 22. The first outer edge portion 22 has a vertical wall portion 222 protruding radially outward at the tip side of the recess 221. The vertical wall portion 222 has a pull-out prevention member 223 extending in the axial direction. The pull-out prevention member 223 is fitted into the through hole 621 of the flange portion 62. The pull-out prevention member 223 is a member that fixes the vertical wall portion 222 to the flange portion 62.

The second outer edge portion 26 is provided on the outer periphery side of the first outer edge portion 22. The second flexible portion 25 connects the bushing fitting portion 20 and the second outer edge portion 26. In a cross section including the central axis Z, the second flexible portion 25 is substantially U-shaped. The second outer edge portion 26 is disposed at the end of the second flexible portion 25. The second outer edge portion 26 has a convex portion 261 that protrudes radially inward. The convex portion 261 is fitted into the concave portion 221 of the first outer edge portion 22.

The bushing 5 is a bearing that rotatably supports the second steering shaft 85. The bushing 5 is made of a synthetic resin such as nylon.

As shown in FIG. 7, the bushing 5 extends in an annular shape along the circumferential direction around the central axis Z of the second steering shaft 85. The bushing 5 includes a base 50, an outer flange 51, an inner flange 52, and a plurality of lubricant grooves 59.

The base 50 extends cylindrically in the circumferential direction around the central axis Z of the second steering shaft 85. The outer flange 51 protrudes radially outward (outer periphery) from the end of the base 50 on the outer side of the vehicle cabin. The inner flange 52 protrudes radially outward (outer periphery) from the end of the base 50 on the vehicle cabin side. The fixing portion 54 is provided on the outer periphery of the bush 5. That is, the fixing portion 54 is formed by the base 50, the outer flange 51, and the inner flange 52. The bush fitting portion 20 of the bellows 2 fits into the fixing portion 54. The lubricant groove 59 is a groove provided on the inner peripheral surface of the base 50, and is, for example, along the axial direction. The lubricant groove 59 extends over the entire axial length of the bush 5. For example, a plurality of lubricant grooves 59 are arranged at equal intervals in the circumferential direction. The lubricant groove 59 is filled with grease as a lubricant. This reduces friction between the inner surface 53 of the bush 5 and the outer surface 85a of the second steering shaft 85.

The seal lip 11 is a sealing member that separates the gap between the second steering shaft 85 and the bush 5 from the engine room. The seal lip 11 is, for example, nitrile rubber (NBR) and is integrated with the bush 5 by vulcanization adhesion. As shown in FIG. 7, the seal lip 11 protrudes from the first end face 551 of the bush 5 to the outside of the vehicle cabin. The first end face 551 is the end face of the bush 5 on the outside of the vehicle cabin. The minimum inner diameter of the seal lip 11 before contacting the outer circumferential surface 85a of the second steering shaft 85 is smaller than the outer diameter of the second steering shaft 85. Therefore, when the seal lip 11 contacts the outer circumferential surface 85a of the second steering shaft 85, the seal lip 11 is deformed. Due to the elasticity of the seal lip 11, a gap between the seal lip 11 and the second steering shaft 85 is less likely to occur. Therefore, the seal lip 11 can prevent foreign matter from entering the inside of the bush 5 from the engine room, and can prevent grease from leaking from the inside of the bush 5 to the engine room. The seal lip 11 also prevents noise generated in the engine room from leaking into the vehicle interior.

The end of the bush 5 on the cabin side is the second end face 552. That is, the inner flange 52 has an end face 521 on the outside of the cabin, an outer peripheral surface 522, and a second end face 552 which is the end face on the cabin side. In other words, the area with a rectangular cross section surrounded by the end face 521, the outer peripheral surface 522, and the second end face 552 is the inner flange 52. The outer peripheral surface 522 is the end of the bush 5 on the outer peripheral side. The inner peripheral surface 53 of the bush 5 is the end of the bush 5 on the inner peripheral side.

Furthermore, the vertical wall portion 211 on the vehicle compartment side of the first flexible portion 21 extends in the radial direction (the up-down direction in FIG. 7). A seal lip 100 (sealing member) extends from the vertical wall portion 211 toward the vehicle compartment side (to the right in FIG. 7). The seal lip 100 is integrally molded with the vertical wall portion 211 of the bellows 2. The seal lip 100 is formed from the same rubber as the bellows 2. The seal lip 100 includes a main body portion 110 and a tip portion 120. The main body portion 110 extends along the axial direction from the vertical wall portion 211.

The tip portion 120 has an outer peripheral surface 122 and an inner peripheral surface 123. In a cross section including the central axis Z, the tip portion 120 tapers toward the vehicle cabin side. The edge 121 of the tip portion 120 is the end portion on the inner peripheral side of the seal lip 100, and is also the end portion on the vehicle cabin side of the seal lip 100. The edge 121 of the tip portion 120 is located radially inward (inner peripheral side) than the outer peripheral surface 522 of the inner flange 52 of the bush 5. In addition, the edge 121 of the tip portion 120 is located closer to the vehicle cabin side than the second end face 552 of the bush 5. Furthermore, the edge 121 of the tip portion 120 is located radially outward (outer peripheral side) than the inner peripheral surface 53 of the bush 5. As a result, the edge 121 of the tip portion 120 is located outer peripheral side than the outer peripheral surface 85a of the second steering shaft 85, so that a gap is provided between the edge 121 and the outer peripheral surface 85a of the second steering shaft 85. The seal lip 100 has a contact portion 140 on the inner circumferential side. The contact portion 140 is a groove 130. The groove 130 is a portion surrounded by a first inner circumferential surface 131, a second inner circumferential surface 132, and a third inner circumferential surface 133. In a cross section including the central axis Z, the first inner circumferential surface 131 and the third inner circumferential surface 133 extend in the radial direction, and the second inner circumferential surface 132 extends along the axial direction. The groove 130 is fitted into the outer circumferential end portion of the inner flange 52. In detail, the second inner circumferential surface 132 contacts the outer circumferential surface 522 of the inner flange 52. The first inner circumferential surface 131 contacts the end surface 521. The third inner circumferential surface 133 contacts the second end surface 552.

As described above, the dust cover 1 includes the bush 5 and the bellows 2. The seal lip 100 (sealing member) is integrally molded with the bellows 2. That is, the bellows 2 has the seal lip 100 (sealing member). In the seal lip 100, the edge 121 (end on the inner periphery) of the tip portion 120 is located more inward than the outer periphery surface 522 (end on the outer periphery side of the bush 5) of the bush 5, and the edge 121 (end on the cabin side) is located more inward than the second end surface 552 (end on the cabin side of the bush 5) of the bush 5.

In this way, the seal lip 100 is molded integrally with the bellows 2. Therefore, compared to the conventional method of fixing the seal lip to the bush by vulcanization adhesion, this embodiment omits the adhesive application process and the seal lip insert molding process, making it easier to mold (manufacture) the seal lip 100. This has the advantage that the molding work for the seal lip 100 can be performed at low cost.

In addition, the edge 121 (the end on the inner periphery side) of the tip portion 120 is located on the outer periphery side of the inner periphery surface 53 (the end on the inner periphery side of the bush 5) of the bush 5. As a result, a gap is provided between the edge 121 and the outer periphery surface 85a of the second steering shaft 85. Here, if the edge 121 and the outer periphery surface 85a of the second steering shaft 85 are in contact with each other, stick-slip may occur between the edge 121 and the outer periphery surface 85a due to the rotation of the second steering shaft 85. Here, stick-slip refers to self-excited vibration caused by repeated adhesion and slippage of microscopic friction surfaces that occur between friction surfaces. In particular, stick-slip is likely to occur when the seal lip 100 is made of soft rubber. However, in this embodiment, a gap is provided between the edge 121 of the seal lip 100 and the outer periphery surface 85a of the second steering shaft 85, which has the advantage that abnormal noise due to stick-slip is less likely to occur. In addition, partial contact between the seal lip 100 and the second steering shaft 85 only occurs when the second steering shaft 85 is excessively eccentric, thereby increasing the axial support rigidity of the bush 5 and supporting the waterproof seal function of the seal lip 11 on the outside of the vehicle compartment. Furthermore, a gap is provided between the edge 121 of the seal lip 100 and the outer peripheral surface 85a of the second steering shaft 85, but by adjusting the size of the gap, contact between the outer peripheral surface 85a and the edge 121 of the seal lip 100 due to the inclination of the second steering shaft 85 can be prevented, and sufficient dustproof performance can be obtained for practical use with a simple seal structure on the vehicle compartment side, where waterproofing is not required as much.

The bush 5 has an inner flange 52 (flange) that protrudes outward, and the inner circumferential surface 123 of the seal lip 100 (seal member) has a contact portion 140 that contacts the inner flange 52. As a result, the seal lip 100 is supported radially by the inner flange 52, making it possible to more reliably maintain the gap between the edge 121 of the seal lip 100 and the outer circumferential surface 85a of the second steering shaft 85.

The contact portion 140 has a recessed groove 130 that recesses toward the outer periphery, and the inner flange 52 (flange) fits into the recessed groove 130. This makes it possible to keep the axial position of the seal lip 100 constant.

[First Modification]
Next, the first modified example will be described. FIG. 8 is an enlarged cross-sectional view of the seal lip according to the first modified example. The vertical wall portion 211 on the vehicle compartment side of the first flexible portion 21 extends in the radial direction (the vertical direction in FIG. 8). A seal lip 100A (seal member) extends from the vertical wall portion 211 toward the vehicle compartment side. The seal lip 100A includes a main body portion 110A and a tip portion 120A. The main body portion 110A extends along the axial direction from the vertical wall portion 211. The tip portion 120A has an outer peripheral surface 122 and an inner peripheral surface 123A. In a cross section including the central axis Z, the tip portion 120A tapers toward the vehicle compartment side. In addition, the end edge 121A of the tip portion 120A is located radially inward (inner peripheral side) than the outer peripheral surface 522 of the inner flange 52 of the bush 5. In addition, the edge 121A of the tip portion 120A is located closer to the vehicle cabin than the second end face 552 of the bush 5. Furthermore, the edge 121A of the tip portion 120A is located radially outward (outer circumferential side) than the inner circumferential surface 53 of the bush 5.

The seal lip 100A also has a contact portion 140A on the inner circumferential side. The contact portion 140A has a first inner circumferential surface 131A and a second inner circumferential surface 132A. In a cross section including the central axis Z, the first inner circumferential surface 131A extends in the radial direction, and the second inner circumferential surface 132A extends along the axial direction. The first inner circumferential surface 131A contacts the end face 521. The second inner circumferential surface 132A contacts the outer circumferential surface 522 of the inner flange 52.

In the first modified example, there is no recessed groove 130 as in the embodiment, and the first inner circumferential surface 131A and the second inner circumferential surface 132A, which are the contact portion 140A, are in contact with the inner flange 52.

As described above, in the first modified example, the bush 5 has an inner flange 52 (flange) that protrudes toward the outer periphery, and the inner circumferential surface 123A of the seal lip 100A (seal member) has a contact portion 140A that contacts the inner flange 52. In particular, in the first modified example, there is no recessed groove 130 as in the embodiment, and the first inner circumferential surface 131A and the second inner circumferential surface 132A, which are the contact portion 140A, contact the inner flange 52. This allows the seal lip 100A to move in the axial direction, and the seal lip 100A to be supported in the radial direction by the inner flange 52.

[Second Modification]
Next, a second modified example will be described. Fig. 9 is a cross-sectional view of a dust cover according to the second modified example. As shown in Fig. 9, the mounting member 6A in the dust cover 1A includes a main body portion 61A and a flange portion 62A. The main body portion 61A is cylindrical and extends in the circumferential direction of the central axis Z of the second steering shaft 85. The main body portion 61A has an outer peripheral surface 611A. The outer peripheral surface 611A is provided with a recess 612A recessed toward the inner peripheral side. The flange portion 62A protrudes from the main body portion 61A toward the radially outward (outer peripheral side).

The first outer edge 22A of the first flexible portion 21A of the bellows 2A has a convex portion that protrudes radially inward (toward the inner circumference). The first outer edge 22A of the bellows 2A fits into the concave portion 612A of the main body portion 61A of the mounting member 6A. The end of the second flexible portion 25A has a second outer edge 26A. The second outer edge 26A has a convex portion that protrudes toward the inner circumference. The second outer edge 26A is fitted between the first outer edge 22A and the flange portion 62A.

The seal lip 100 of the second modified example is the same as the seal lip 100 described in the embodiment.

As described above, the second modified example differs from the embodiment and the first modified example in the fixing structure between the bellows and the mounting member 6. However, the present invention can be applied to any of the fixing structures between the bellows and the mounting member 6 in the embodiment, the first modified example, and the second modified example.

[Third Modification]
Next, a third modified example will be described. Fig. 10 is a front view of a dust cover according to the third modified example. Fig. 11 is a cross-sectional view taken along line B-B in Fig. 10. Fig. 12 is a cross-sectional view showing an enlarged portion of Fig. 11. The third modified example differs from the embodiment in the shape of the seal lip 100B (seal member) and the number of the retaining members 223. This will be described in detail below.

In the above-described embodiment, three anti-pullout members 223 are arranged at equal intervals along the circumferential direction of the dust cover 1. In contrast, in the third modified example, the dust cover 1B has four anti-pullout members 223 as shown in FIG. 10. That is, four anti-pullout members 223 are arranged at equal intervals along the circumferential direction of the dust cover 1B. Also, as shown in FIG. 10, the seal lip 100B (seal member) has a slit 150 extending from the inner circumferential end toward the outer circumferential side. Therefore, the inner circumferential end of the slit 150 is open. Eight slits 150 are provided at equal intervals along the circumferential direction. Note that in the present disclosure, the number of slits 150 is not particularly limited, and they do not have to be arranged at equal intervals.

As shown in FIG. 12, the vertical wall portion 211 on the vehicle compartment side of the first flexible portion 21 extends in the radial direction. A seal lip 100B (sealing member) extends from the vertical wall portion 211 toward the vehicle compartment side. The seal lip 100B is integrally molded with the vertical wall portion 211 of the bellows 2B. The seal lip 100B is formed from the same rubber as the bellows 2. The seal lip 100B includes a main body portion 110 and a tip portion 120B. The main body portion 110 extends from the vertical wall portion 211 along the axial direction.

The tip portion 120B has an outer peripheral surface 122B and an inner peripheral surface 123B. In a cross section including the central axis Z, the tip portion 120B tapers toward the vehicle compartment. The edge 121B of the tip portion 120B is the end portion on the inner peripheral side of the seal lip 100B, and is also the end portion on the vehicle compartment side of the seal lip 100B. The edge 121B of the tip portion 120B is located radially inward (inner peripheral side) than the outer peripheral surface 522 of the inner flange 52 of the bush 5. The edge 121B of the tip portion 120B is also located closer to the vehicle compartment than the second end face 552 of the bush 5. Furthermore, the edge 121B of the tip portion 120B is located radially inward (inner peripheral side) than the inner peripheral surface 53 of the bush 5.

As described above, the seal lip 100B has a slit 150 extending from the edge 121B (the end on the inner periphery side) toward the outer periphery. The slit 150 is formed in the body portion 110 and the tip portion 120B over substantially the entire tip portion 120B.

As described above, in the third modified example, the edge 121B of the tip portion 120B is located radially inward (on the inner circumferential side) of the inner circumferential surface 53 of the bush 5. In addition, the seal lip 100B (sealing member) has a slit 150 that extends from the edge 121B (the end on the inner circumferential side) toward the outer circumferential side.

In this way, the edge 121B of the tip portion 120B is located on the inner side of the outer circumferential surface 85a of the second steering shaft 85, so that the edge 121B and the outer circumferential surface 85a of the second steering shaft 85 come into contact with each other. As a result, it is possible to prevent foreign matter such as dust from entering the vehicle interior. Furthermore, since the seal lip 100B has a slit 150, it has a lower rigidity than a seal lip without a slit 150. Therefore, when the edge 121B of the tip portion 120B comes into contact with the outer circumferential surface 85a of the second steering shaft 85, friction between the tip portion 120B and the second steering shaft 85 is reduced. Furthermore, it is possible to suppress the generation of abnormal noise due to stick-slip between the edge 121B of the seal lip 100B and the second steering shaft 85. As described above, by positioning the edge 121B of the tip 120B of the seal lip 100B on the inner side of the outer circumferential surface 85a of the second steering shaft 85 and forming a slit 150 in the seal lip 100B, it is possible to simultaneously prevent foreign matter such as dust from entering the vehicle cabin, reduce friction between the tip 120B and the second steering shaft 85, and suppress the generation of abnormal noise due to stick-slip between the edge 121B of the seal lip 100B and the second steering shaft 85.

1, 1A, 1B Dust cover 2, 2A, 2B Bellows 5 Bush 52 Inner flange (flange)
53 Inner circumferential surface (end portion on the inner circumferential side)
100, 100A, 100B Seal lip (seal member)
121, 121A, 121B Edges (ends on the inner circumference side, end on the cabin side)
123, 123A, 123B Inner circumferential surface 130 Groove 140, 140A Contact portion 522 Outer circumferential surface (end portion on the outer circumferential side)
552 Second end face (end face on the vehicle cabin side)

Claims (3)

A bush attached to an outer circumferential surface of a steering shaft that passes through a cylindrical member of a dash panel;
and an annular bellows that closes a gap between the cylindrical member and the bush.
the bellows has a seal member having an inner circumferential end located more inward than an outer circumferential end of the bush and an interior-side end located more toward the interior of the vehicle than an interior-side end of the bush,
the seal member has a slit extending from the inner circumferential end toward the outer circumferential end,
an inner peripheral end of the seal member is located more inward than an inner peripheral end of the bush;
Dust cover. The bushing includes a flange protruding outwardly,
The inner circumferential surface of the seal member has a contact portion that contacts the flange.
The dust cover of claim 1 . The contact portion of the seal member has a recessed groove recessed toward an outer periphery side,
The flange of the bush is fitted into the recessed groove of the contact portion.
The dust cover of claim 2 .

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