JP7488794B2 - Sealing material - Google Patents

Description

The present invention relates to a sealing member.

Patent document 1 discloses a structure in which a piston cup is housed in a groove formed in the piston to seal between the piston and a cylinder in which the piston is housed so that it can reciprocate.

Japanese Patent Application Laid-Open No. 11-101349

In the case of Patent Document 1, when hydraulic pressure acts on the groove in which the piston cup is housed, pressing the piston cup against the piston and cylinder, part of the piston cup may get into the gap between the piston and cylinder and be scraped off, resulting in damage.

The sealing member of the present invention seals between a piston and a cylinder, and has an annular base attached to the piston, an outer lip protruding from the outer peripheral edge of the base and contacting the cylinder, and an inner lip protruding from the inner peripheral edge of the base and contacting the piston, and a plurality of hemispherical protrusions are formed on the outer peripheral surface of the base along the circumferential direction of the base.

Alternatively, the sealing member of the present invention seals between a piston and a cylinder, and has an annular base attached to the cylinder, an outer lip protruding from the outer peripheral edge of the base and contacting the cylinder, and an inner lip protruding from the inner peripheral edge of the base and contacting the piston, and a plurality of hemispherical protrusions are formed on the inner surface of the base along the circumferential direction of the base.

When multiple protrusions are formed on the outer peripheral surface of the base of the sealing member, the inner base portion of the outer lip may be padded.

When multiple protrusions are formed on the inner circumferential surface of the base of the sealing member, the inner base portion of the inner lip may be padded.

The sealing member of the present invention can prevent the bottom edge of the base from getting caught in the gap between the piston and the cylinder, which is known as "cracking," and can prevent sealing failures caused by damage resulting from this "cracking."

1 is an explanatory diagram showing a schematic configuration of a main part of a wheel cylinder to which a cup seal of a first embodiment is applied; FIG. 4 is a perspective view of a cup seal according to the first embodiment. FIG. 4 is a cross-sectional view of the cup seal in the first embodiment. FIG. 4 is an explanatory diagram showing a schematic state of a cup seal in a wheel cylinder. A characteristic diagram showing the correlation between the hydraulic pressure in the wheel cylinder and the amount of wear in the cup seal. FIG. 4 is a cross-sectional view of a cup seal in a comparative example. FIG. 11 is a cross-sectional view of a cup seal in a second embodiment. FIG. 11 is a cross-sectional view of a cup seal in a third embodiment. FIG. 13 is an explanatory diagram showing a schematic configuration of a main part of a wheel cylinder to which a cup seal of a fourth embodiment is applied. FIG. 13 is a perspective view of a cup seal in a fourth embodiment. FIG. 13 is a cross-sectional view of a cup seal in a fourth embodiment. FIG. 13 is a cross-sectional view of a cup seal in the fifth embodiment. FIG. 13 is a cross-sectional view of a cup seal in the sixth embodiment.

Below, one embodiment of the present invention will be described in detail with reference to the drawings.

Figure 1 is an explanatory diagram showing the schematic configuration of the main part of a wheel cylinder 1 to which the cup seal 4 of the first embodiment is applied. In other words, Figure 1 is an explanatory diagram showing a schematic cross section of the main part of a wheel cylinder 1 to which the cup seal 4 of the first embodiment is applied.

The wheel cylinder 1 is used, for example, in a hydraulic brake that generates a braking force using hydraulic pressure. The wheel cylinder 1 has a cylinder body 2, a cylindrical piston 3 (3a, 3b) inserted in series into the cylinder body 2, and an annular cup seal 4 as a sealing member that seals between the piston 3 and the inner peripheral surface 2a of the cylinder body 2. The wheel cylinder 1 is capable of supplying hydraulic pressure from a master cylinder (not shown) to a hydraulic pressure chamber (hydraulic pressure chamber) 5 in the cylinder body 2 via a hydraulic pressure supply path (hydraulic pressure supply path) 6. Here, the hydraulic pressure from the master cylinder is, in other words, hydraulic pressure.

The hydraulic pressure chamber 5 is a space sandwiched between the pistons 3a and 3b, and hydraulic pressure is applied to the pistons 3a and 3b on both sides. The pistons 3 reciprocate (slide) in response to the hydraulic pressure from the hydraulic pressure chamber 5, transmitting force to brake shoes (not shown). For example, when the hydraulic pressure in the hydraulic pressure chamber 5 increases, the piston 3a moves to the right in FIG. 1, and the piston 3b moves to the left in FIG. 1. The pistons 3a and 3b transmit force to their corresponding brake shoes. In other words, when the hydraulic pressure in the hydraulic pressure chamber 5 increases, the wheel cylinder 1 transmits force to the brake shoes so that the brake shoes are pressed against the drum.

Pistons 3a and 3b have grooves 7 on their outer circumferential surfaces 12 in which cup seals 4 are housed. Groove 7 is an endless groove that continues along the circumferential direction of piston 3 on outer circumferential surface 12 of piston 3, and is formed so that the length along the axial direction of piston 3 is longer than the length of cup seal 4 (axial length of cup seal 4).

The cup seal 4 of the first embodiment is a so-called outer diameter sliding type that is attached to the groove 7 of the piston 3 and has its outer periphery sliding against the inner periphery 2a (cylinder wall surface) of the cylinder body 2. The cup seal 4 has a U-shaped cross section and is attached to the groove 7 with the opening of the U facing the hydraulic chamber 5. The cup seal 4 is made of, for example, a rubber material, and provides a seal between the piston 3 and the inner periphery 2a of the cylinder body 2, i.e., between the piston 3 and the cylinder.

Figures 2 and 3 show the cup seal 4 of the first embodiment. Figure 2 is a perspective view of the cup seal 4 in the first embodiment. Figure 3 is a cross-sectional view of the cup seal 4 in the first embodiment along the cup seal 4 axial direction. The cup seal 4 axial direction is, for example, the same as the axial direction of the piston 3 to which the cup seal 4 is attached.

The cup seal 4 is made of solid rubber such as EPDM, and seals between the piston 3 and the cylinder body 2 to prevent the working fluid in the hydraulic chamber 5 from leaking out of the cylinder body 2. In other words, the hydraulic pressure in the hydraulic chamber 5 acts on the cup seal 4. The cup seal 4 is also called, for example, a brake cup or a piston cup.

The cup seal 4 has an annular base 8 with a roughly rectangular cross section, an outer lip 9 that protrudes from the top surface of the base 8 and is inclined toward the outside in the radial direction of the cup seal 4, and an inner lip 10 that protrudes from the top surface of the base 8 and is inclined toward the inside in the radial direction of the cup seal 4.

The outer lip 9 protrudes from the outer peripheral edge of the base 8 and is in sliding contact with the inner peripheral surface 2a of the cylinder body 2. The inner lip 10 protrudes from the inner peripheral edge of the base 8 and is in contact with the bottom surface 7a of the groove portion 7 of the piston 3.

The cup seal 4, which is an outer diameter sliding type, is formed so that the inner lip 10 has a greater (longer) protruding length (protruding amount) from the base 8 than the outer lip 9, and the inner lip 10 is thinner than the outer lip 9.

The base 8 is formed so that its thickness along the axial direction of the cup seal 4 is relatively thick.

When the piston 3 with the cup seal 4 attached is assembled to the cylinder body 2, the outer peripheral surface 8a of the base 8, located on the outer peripheral side in the radial direction of the cup seal 4, faces the inner peripheral surface 2a of the cylinder body 2, and the inner peripheral surface 8b, located on the inner peripheral side in the radial direction of the cup seal 4, faces the bottom surface 7a of the groove portion 7 formed in the piston 3.

The outer peripheral surface 8a of the base 8 has a number of circular projections 11 formed in a row at intervals along the circumferential direction of the base 8. The projections 11 are, for example, dome-shaped (hemispherical) and protrude from the outer peripheral surface 8a.

The piston 3 is able to slide against the inner circumferential surface 2a of the cylinder body 2, and the maximum outer diameter of the piston 3 is smaller than the inner diameter of the cylinder body 2. Therefore, the hydraulic pressure in the hydraulic chamber 5 acts on the cup seal 4 in the groove portion 7. When the hydraulic pressure from the hydraulic chamber 5 is applied to the cup seal 4, the outer lip 9 is pressed against the cylinder body 2, and the inner lip 10 is pressed against the piston 3, thereby sealing between the inner circumferential surface 2a of the cylinder body 2 and the piston 3.

Figure 4 is an explanatory diagram that shows a schematic diagram of the state of the cup seal 4 inside the wheel cylinder 1.

As shown in FIG. 4, when the hydraulic pressure of the hydraulic pressure chamber 5 acts on the cup seal 4, a phenomenon called "crack" may occur in which a part of the cup seal 4 gets into the gap between the inner peripheral surface 2a of the cylinder body 2 and the outer peripheral surface 12 of the piston 3. More specifically, when the hydraulic pressure of the hydraulic pressure chamber 5 acts on the cup seal 4 of the outer diameter sliding type, the bottom outer peripheral edge of the base 8 may get into the gap between the outer peripheral surface 12 of the piston 3 and the inner peripheral surface 2a of the cylinder body 2 as a crack 15. In the case of the cup seal 4 of the inner diameter sliding type described later, the bottom inner peripheral edge of the base 8 may get into the gap between the outer peripheral surface 12 of the piston 3 and the inner peripheral surface 2a of the cylinder body 2 as a crack 15.

Here, in this specification, the portion of the cup seal that has entered the gap between the outer peripheral surface 12 of the piston 3 and the inner peripheral surface 2a of the cylinder body 2 is defined as the crevice portion 15 of the cup seal. Also, in this specification, the length of the crevice portion 15 along the axial direction of the cup seal is defined as the crevice amount.

Figure 5 is a characteristic diagram showing the correlation between the hydraulic pressure in hydraulic chamber 5, which is the hydraulic pressure in wheel cylinder 1, and the amount of flaking of cup seal 4. Characteristic line A shown by a solid line in Figure 5 shows the characteristics of the amount of flaking of cup seal 4 in the above-mentioned embodiment. Characteristic line B shown by a dashed line in Figure 5 shows the characteristics of the amount of flaking of cup seal 21 in the comparative example.

The higher the hydraulic pressure in the hydraulic chamber 5, the more the cup seal 4 is pressed in the opposite direction to the hydraulic chamber 5. Therefore, as shown in Figure 5, the amount of tearing is proportional to the hydraulic pressure in the hydraulic chamber 5, and the higher the hydraulic pressure, the longer (larger) the tearing becomes.

As shown in FIG. 6, the cup seal 21 of the comparative example has substantially the same configuration as the cup seal 4 of the first embodiment described above, with the only difference being the presence or absence of the protrusion 11. In other words, the cup seal 21 of the comparative example has a shape in which the protrusion 11 has been removed from the cup seal 4 of the embodiment described above. In the cup seal 21 of the comparative example shown in FIG. 6, the same components as those of the cup seal 4 of the first embodiment are given the same reference numerals and redundant explanations will be omitted.

When hydraulic pressure is applied to the cup seal 4 of the first embodiment described above, the protrusion 11 acts as a stopper to prevent the bottom outer peripheral edge of the base 8 from entering the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2. In other words, because the cup seal 4 has the protrusion 11 on the outer peripheral surface 8a of the base 8, the force pressing the bottom outer peripheral edge of the base 8 into the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2 is reduced when hydraulic pressure is applied.

As a result, the cup seal 4 of the first embodiment can suppress the amount of tearing compared to the cup seal 21 of the comparative example, as shown in Figure 5.

As a result, the cup seal 4 of the first embodiment can prevent the bottom outer peripheral edge of the base 8 from biting (entering) into the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2, which is known as "biting," and can prevent sealing failures caused by damage due to this "biting." In other words, when hydraulic pressure is applied to the cup seal 4 of the first embodiment, the bottom outer peripheral edge of the base 8 is less likely to enter (bite) into the gap between the piston 3 and the cylinder, making the bottom outer peripheral edge of the base 8 less likely to be damaged and preventing deterioration of sealing performance.

The cup seal 4 has protrusions 11 on the outer peripheral surface 8a of the base 8 that are not continuous in the circumferential direction, which prevents a decrease in sliding ability against the inner peripheral surface 2a of the cylinder body 2 while making it difficult for the bottom outer peripheral edge of the base 8 to get into (bite into) the gap between the piston 3 and the cylinder.

Below, we will explain another embodiment of the present invention. Note that the same components as those in the cup seal 4 of the first embodiment described above will be given the same reference numerals and duplicate explanations will be omitted.

A second embodiment of the present invention will be described with reference to Figure 7. Figure 7 is a cross-sectional view of the cup seal 22 of the second embodiment taken along the axial direction of the cup seal 22.

The cup seal 22 of the second embodiment has substantially the same configuration as the cup seal 4 of the first embodiment described above, but the inner base portion of the outer lip 9 is padded in a stepped manner to form a bulge 23. In other words, the cup seal 22 of the second embodiment is formed so that a solid bulge 23 protrudes from the inner base portion of the outer lip 9. In the cup seal 22 of the second embodiment, the bulge 23 makes the base portion of the outer lip 9 thicker than the tip side of the outer lip 9.

The cup seal 22 of the second embodiment can achieve substantially the same effects as the cup seal 4 of the first embodiment described above.

In addition, the bulge 23 of the cup seal 22 of the second embodiment increases the rigidity of the outer lip 9, making it less likely for the outer lip 9 to collapse inward. As a result, the cup seal 22 of the second embodiment is less likely to deform so that the bottom outer peripheral edge of the base 8 tapers due to the outer lip 9 collapsing inward, making it even less likely for the bottom outer peripheral edge of the base 8 to penetrate (bite into) the gap between the piston 3 and the cylinder. In other words, by providing the bulge 23 of the cup seal 22 of the second embodiment, it is even more difficult for the bottom outer peripheral edge of the base 8 to penetrate (bite into) the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2, making it possible to further suppress deterioration of sealing performance.

A third embodiment of the present invention will be described with reference to Figure 8. Figure 8 is a cross-sectional view of the cup seal 24 of the third embodiment taken along the axial direction of the cup seal 24.

The cup seal 24 of the third embodiment has substantially the same configuration as the cup seal 4 of the first embodiment described above, but the inner root portion of the outer lip 9 is padded to have a curvature to form a bulge 25. In other words, the cup seal 24 of the third embodiment is formed so that a solid bulge 25 protrudes from the inner root portion of the outer lip 9. In the cup seal 24 of the third embodiment, the bulge 25 makes the root portion of the outer lip 9 thicker than the tip side of the outer lip 9.

The cup seal 24 of the third embodiment can achieve substantially the same effects as the cup seal 4 of the first embodiment described above.

In addition, the cup seal 24 of the third embodiment has an increased rigidity of the outer lip 9 due to the bulge 25, making it less likely for the outer lip 9 to collapse inward. As a result, the cup seal 24 of the third embodiment is less likely to deform so that the bottom outer peripheral edge of the base 8 tapers due to the outer lip 9 collapsing inward, making it even less likely for the bottom outer peripheral edge of the base 8 to penetrate (bite) into the gap between the piston 3 and the cylinder. In other words, like the cup seal 22 of the second embodiment described above, the cup seal 24 of the third embodiment has a bulge 25, making it even more difficult for the bottom outer peripheral edge of the base 8 to penetrate (bite) into the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2, and further suppressing deterioration of the sealing performance.

The cup seal 30 of the fourth embodiment will be described with reference to Figures 9 to 11. Figure 9 is an explanatory diagram showing the schematic configuration of the main parts of a wheel cylinder 31 to which the cup seal 30 of the fourth embodiment is applied. In other words, Figure 9 is an explanatory diagram showing a schematic cross-section of the main parts of a wheel cylinder 31 to which the cup seal 30 of the fourth embodiment is applied.

The cup seal 30 of the fourth embodiment has a configuration substantially identical to that of the cup seal 4 of the first embodiment described above, but is a so-called inner diameter sliding type that is attached to a groove portion 32 formed in the inner circumferential surface 2a of the cylinder body 2 and slides against the outer circumferential surface 12 of the piston 3.

The wheel cylinder 31 has a configuration that is substantially the same as the wheel cylinder 1 to which the cup seal 4 of the first embodiment is applied, but the cup seal 30 of the fourth embodiment is attached to the groove 32 of the cylinder body 2, not to the piston 3. Therefore, the piston 3 does not have a groove 7 for attaching the cup seal 30.

The cup seal 30 of the fourth embodiment has a configuration substantially identical to that of the cup seal 4 of the first embodiment described above, and has an annular base 8 with a substantially rectangular cross section, an outer lip 9 that protrudes from the top surface of the base 8 and is inclined toward the outside in the radial direction of the cup seal 30, and an inner lip 10 that protrudes from the top surface of the base 8 and is inclined toward the inside in the radial direction of the cup seal 30.

The outer lip 9 protrudes from the outer peripheral edge of the base 8 and contacts the bottom surface 32a of the groove 32 of the cylinder body 2. The inner lip 10 protrudes from the inner peripheral edge of the base 8 and slidably contacts the outer peripheral surface 12 of the piston 3.

The cup seal 30, which is an inner diameter sliding type, is formed so that the outer lip 9 has a greater (longer) protruding length (protruding amount) from the base 8 than the inner lip 10, and the outer lip 9 is thinner than the inner lip 10.

The base 8 is formed so that its thickness along the axial direction of the cup seal 30 is relatively thick.

When the piston 3 is assembled to the cylinder body 2, the outer peripheral surface 8a of the base 8, located on the outer peripheral side in the radial direction of the cup seal 30, faces the bottom surface 32a of the groove portion 32, and the inner peripheral surface 8b, located on the inner peripheral side in the radial direction of the cup seal 30, faces the outer peripheral surface 12 of the piston 3.

The cup seal 30 of the fourth embodiment has multiple projections 11 with circular outer shapes formed in a row at intervals along the circumferential direction of the base 8 on the inner circumferential surface 8b of the base 8. The projections 11 are, for example, dome-shaped (hemispherical) and protrude from the inner circumferential surface 8b.

When hydraulic pressure is applied to the cup seal 30 of the fourth embodiment, the protrusion 11 acts as a stopper to prevent the inner peripheral edge of the bottom of the base 8 from entering the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2. In other words, the cup seal 30 has the protrusion 11 on the inner peripheral surface 8b of the base 8, which reduces the force pressing the inner peripheral edge of the bottom of the base 8 into the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2 when hydraulic pressure is applied.

The cup seal 30 of the fourth embodiment can achieve substantially the same effects as the cup seal 4 of the first embodiment described above.

In other words, the cup seal 30 of the fourth embodiment can suppress so-called "cracking" in which the inner peripheral edge of the bottom of the base 8 bites into (enters) the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2, and can suppress sealing failures caused by damage resulting from this "cracking". In other words, when hydraulic pressure is applied to the cup seal 30 of the fourth embodiment, the inner peripheral edge of the bottom of the base 8 is less likely to bite into (enter) the gap between the piston 3 and the cylinder, making it less likely that the inner peripheral edge of the bottom of the base 8 will be damaged, and suppressing deterioration of sealing performance.

In the fourth embodiment of the cup seal 30, the protrusions 11 provided on the inner peripheral surface 8b of the base 8 are not continuous in the circumferential direction, so that the inner peripheral edge of the bottom of the base 8 is less likely to penetrate (bite into) the gap between the piston 3 and the cylinder while suppressing a decrease in sliding performance against the outer peripheral surface 12 of the piston 3.

The fifth embodiment of the present invention will be described with reference to Figure 12. Figure 12 is a cross-sectional view of the cup seal 35 of the fifth embodiment taken along the axial direction of the cup seal 35.

The cup seal 35 of the fifth embodiment has substantially the same configuration as the cup seal 30 of the fourth embodiment described above, but the base portion on the inside of the inner lip 10 is padded in a stepped manner to form a bulge 36. In other words, the cup seal 35 of the fifth embodiment is formed so that a solid bulge 36 protrudes from the base portion on the inside of the inner lip 10. In the cup seal 35 of the fifth embodiment, the bulge 36 makes the base portion of the inner lip 10 thicker than the tip side of the inner lip 10.

The cup seal 35 of the fifth embodiment can achieve substantially the same effects as the cup seal 30 of the fourth embodiment described above.

In addition, the cup seal 35 of the fifth embodiment has an increased rigidity of the inner lip 10 due to the bulge 36, making it less likely for the inner lip 10 to collapse inward. As a result, the cup seal 35 of the fifth embodiment is less likely to deform so that the bottom inner peripheral edge of the base 8 becomes tapered due to the outer lip 9 collapsing inward, making it even less likely for the bottom inner peripheral edge of the base 8 to penetrate (bite) into the gap between the piston 3 and the cylinder. In other words, by providing the bulge 36, the cup seal 35 of the fifth embodiment is even less likely for the bottom inner peripheral edge of the base 8 to penetrate (bite) into the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2, making it possible to further suppress deterioration of the sealing performance.

The sixth embodiment of the present invention will be described with reference to Figure 13. Figure 13 is a cross-sectional view of the cup seal 37 of the sixth embodiment taken along the axial direction of the cup seal 37.

The cup seal 37 of the sixth embodiment has substantially the same configuration as the cup seal 30 of the fourth embodiment described above, but the inner root portion of the inner lip 10 is padded to have a curvature to form a bulge portion 38. In other words, the cup seal 37 of the sixth embodiment is formed so that a solid bulge portion 38 protrudes from the inner root portion of the inner lip 10. In the cup seal 37 of the sixth embodiment, the bulge portion 38 makes the root portion of the inner lip 10 thicker than the tip side of the inner lip 10.

The cup seal 37 of the sixth embodiment can achieve substantially the same effects as the cup seal 30 of the fourth embodiment described above.

In addition, the bulge 38 of the cup seal 37 of the sixth embodiment increases the rigidity of the inner lip 10, making it less likely for the inner lip 10 to collapse inward. As a result, the inner peripheral edge of the bottom of the base 8 of the cup seal 37 of the sixth embodiment is less likely to deform in a tapered manner due to the outer lip 9 collapsing inward, making it even less likely for the inner peripheral edge of the bottom of the base 8 to penetrate (bite) into the gap between the piston 3 and the cylinder. In other words, by providing the bulge 38 of the cup seal 37 of the sixth embodiment, it becomes even more difficult for the inner peripheral edge of the bottom of the base 8 to penetrate (bite) into the gap between the piston 3 and the inner peripheral surface 2a of the cylinder body 2, and deterioration of the sealing performance can be further suppressed.

Although specific examples of the present invention have been described above, the present invention is not limited to the above-mentioned examples, and various modifications are possible without departing from the spirit of the present invention.

For example, the protrusion 11 may be a protrusion (a protrusion) whose outer shape is an oval or ellipse.

In the cup seal of each of the above-mentioned embodiments, the multiple protrusions 11 are arranged in a row along the circumferential direction of the base 8, but it is also possible to arrange the multiple protrusions 11 in multiple rows along the circumferential direction of the base 8. It is also possible to arrange the multiple protrusions 11 in a staggered pattern along the circumferential direction of the base 8.

The cup seal of the present invention can also be applied to sliding parts of hydraulic equipment other than wheel cylinders (such as master cylinders, etc.).

REFERENCE SIGNS LIST 1...wheel cylinder 2...cylinder body 2a...inner peripheral surface 3...piston 3a...piston 3b...piston 4...cup seal 5...hydraulic pressure chamber 6...hydraulic pressure supply passage 7...groove portion 7a...bottom surface 8...base portion 8a...outer peripheral surface 8b...inner peripheral surface 9...outer lip 10...inner lip 11...projection 12...outer peripheral surface 15...cracked portion

Claims (4)

In a sealing member that seals between a piston and a cylinder,
the piston has an annular base attached thereto, an outer lip protruding from an outer circumferential edge of the base and contacting the cylinder, and an inner lip protruding from an inner circumferential edge of the base and contacting the piston,
A sealing member, characterized in that a plurality of hemispherical protrusions are formed on an outer peripheral surface of the base along a circumferential direction of the base. In a sealing member that seals between a piston and a cylinder,
the piston has an annular base attached to the cylinder, an outer lip protruding from an outer circumferential edge of the base and in contact with the cylinder, and an inner lip protruding from an inner circumferential edge of the base and in contact with the piston,
A sealing member, characterized in that a plurality of hemispherical protrusions are formed on an inner peripheral surface of the base along a circumferential direction of the base. The seal member according to claim 1, characterized in that the inner base portion of the outer lip is padded. The seal member according to claim 2, characterized in that the inner base portion of the inner lip is padded.

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