JP2003035365A - Seal ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal ring which does not require special drilling and the like, can excellently seal a gap between a housing bore and a shaft-like body, can easily be press-fitted for sealing, and has a satisfactory come-out-preventing function. SOLUTION: A seal ring 3 for dividing an annular space, that exists between a housing 1 having a bore 10 and a shaft-like body 2 inserted in the housing 1 in a non-contacting state, into an outside space side and a sealed space side comprises an annular metallic core 4 having a cylindrical portion 4a that is nearly concentric with the bore, an elastic body 5 mounted so as to cover the outside periphery of the cylindrical portion of the annular metallic core 4 and brought into contact with the internal surface of the bore 10 under pressure, and an elastic lip 6 attached to the inside diameter side of the annular metallic core 4 and brought into contact with the outside peripheral surface of the shaft-like body 2, wherein the elastic body 5 extends from the annular metallic core 4 toward the outside space side, and tolerance of the interference fit between the extending portion 9 and the internal peripheral surface of the bore 10 is set so as to be larger than that between a portion 8 of the elastic body 5 covering the outside periphery of the annular metallic core 4 and the internal peripheral surface of the bore 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal ring for sealing between a hole formed in a housing of an automobile engine or the like and a shaft-shaped body such as a plug tube inserted into the hole.

[0002]

2. Description of the Related Art Conventionally, as this type of seal ring,
For example, as disclosed in Japanese Unexamined Patent Publication No. 2001-27330, a plug tube is inserted as an example of a shaft-like body into a hole forming a through-hole having a circular cross section formed in a housing such as a cylinder head cover of an engine. It is known to seal a gap between the hole and the plug tube with a seal ring having an elastic lip.

The seal ring is fixed by being press-fitted into the hole.

In this conventional structure, in the seal ring, an elastic body made of a thick elastic rubber is fitted to the outer periphery of the cylindrical annular core bar so that the fitting interference in the press-fitting direction with respect to the hole is substantially constant. It was configured as.

[0005]

In recent years, in order to reduce the weight of vehicles such as automobiles, resin-made members, aluminum alloy-made members and the like have been adopted for various parts such as vehicle bodies. It is known to apply such a resin member to a housing such as an engine cylinder head cover.

By the way, the housing made of resin is
A molded product is generally used, and a seal ring is mounted between a hole formed in the housing and a shaft-shaped body inserted into the hole.

However, in the prior art, the fitted seal ring has a constant fitting interference in the hole of the elastic body in the press-fitting direction, so that the shaft-like body is somewhat centered with respect to the hole. If they are misaligned, if the fitting interference is small, there is a possibility that a gap may be generated due to the deviation of the shaft-like body with respect to the hole, and the sealing performance may be deteriorated.

On the other hand, in order to allow such misalignment sufficiently and improve the sealing property, if the fitting interference is set to a certain large value in the press-fitting direction, the seal ring is press-fitted into the hole because its thickness is large. In addition to being difficult to do, the elastic body may bite into the hole, and a crack may be formed in the elastic body along the press-fitting direction, and oil leakage may occur from the crack.

Further, in order to prevent this misalignment, by separately performing hole processing for improving the shape and position accuracy of the hole of the resin housing, the seal ring can be satisfactorily fitted into the hole. However, it is not possible to improve the productivity because a separate process is required for drilling the hole.

Further, when the fitting interference is constant in the press-fitting direction, a springback phenomenon occurs in which the seal ring is returned in the inserting direction due to friction with the inner peripheral surface of the hole in the elastic body deformed according to the hole. Then, there is a possibility that the seal ring may be slightly lifted from the hole to the side where the seal ring comes out.

Further, since the diameter of the hole of the housing also varies depending on the temperature of the environment with respect to the housing, it is desirable that the sealing performance can be sufficiently maintained even if the diameter varies.

The present invention has been made in view of the above situation, and it is possible to provide a good gap between the hole of the housing and the member inserted into the hole without performing a special hole processing or the like on the hole of the housing. It is an issue to be solved to provide a seal ring that can be sealed in, can be easily press-fitted for sealing, and has a sufficient retaining function.

[0013]

According to a first aspect of the present invention, a seal ring has an annular space formed between a housing having a hole and a shaft-shaped body inserted in a non-contact state with the housing. A seal ring for partitioning into an external space side and a sealed space side, an annular core metal having a cylindrical portion substantially concentric with the hole, and the housing attached to cover the outer periphery of the cylindrical portion of the annular core metal. An elastic body that is pressed against the inner peripheral surface of the hole, and an elastic lip that is attached to the inner diameter side of the annular core metal and is brought into contact with the outer peripheral surface of the shaft-shaped body, , The outer core side of the annular core metal is protruded toward the outer space, and the interference of the protruding portion and the inner peripheral surface of the hole of the housing with the elastic body covers the outer periphery of the annular core metal. At the inner peripheral surface of the hole of the housing That fit Meshiroyori also characterized in that it is set larger.

According to this seal ring, the seal ring can be mounted in the hole even if the housing is still in a molded state and the hole is not processed to improve the dimensional accuracy. For example, if there is a part where the fitting interference is large and the hole and the shaft are slightly decentered, or if the hole size changes somewhat due to temperature, the large interference part As a result, a gap is less likely to be formed between the hole and the elastic body fitting portion, and the sealing performance is high.

Further, although there is some resistance when the portion of the elastic body that projects into the external space having a large fitting margin is press-fitted, the coated portion covered with the annular core metal is fitted more than the projected portion. Because the interference is small,
It is easier to insert than the conventional one, which has a fixed fitting allowance in the press-fitting direction.

In the elastic body, the protruding portion having a large fitting interference mainly exerts a force of closely adhering to the hole in the radial direction, so that the force sufficiently functions as a retainer.

According to a second aspect of the present invention, there is provided a seal ring according to the first aspect, wherein:
On the outer periphery of the elastic body, annular ridges having a large diameter are provided at predetermined intervals in the axial direction.

According to this seal ring, since the annular ridges having large diameters are provided at predetermined intervals in the axial direction on the outer periphery of the elastic body, when the seal ring is press-fitted into the hole, the inner diameter of the hole is increased. Since it is possible to prevent strong frictional contact with the peripheral surface, it does not increase the radial adhesion force sufficiently and functions sufficiently as a retainer, and the seal ring is smoothly press-fitted into the hole. Can be combined. Further, the springback phenomenon in which the press-fitted seal ring floats up as in the conventional case is suppressed.

According to a third aspect of the present invention, in the seal ring according to the first or second aspect, the seal ring is provided on the outer periphery of the elastic body near the outer space side end position of the annular core metal. Is characterized in that an annular groove is provided.

According to this seal ring, when the seal ring is press-fitted into the hole, the protruding portion having a large fitting interference is provided on the outer periphery of the elastic body near the short position of the annular core on the outer space side. The formed annular groove portion facilitates bending deformation toward the inner diameter side, which facilitates press fitting despite the large fitting interference.

As described in claim 4, the seal ring according to the present invention is characterized in that, in the seal ring according to claim 2 or 3, three or more annular ridges are provided.

According to this seal ring, since three or more annular ridges are provided, three or more contact points are dispersed in the press-fitting direction so that the seal ring fits into the hole. It is easier to insert the seal ring than the one that adheres evenly with a uniform compression force, the retaining force for the hole acts sufficiently, and the springback phenomenon is less likely to occur.

According to a fifth aspect of the present invention, there is provided a seal ring according to any one of the first to fourth aspects, wherein the annular ridge portion is fitted to the inner peripheral surface of the hole. Is set so that the closer to the protruding portion, the larger.

According to this seal ring, the fitting interference of the annular ridge portion with respect to the inner peripheral surface of the hole is set such that the closer it is to the projecting portion, the larger the interference is. The stronger the effect is toward the outer space side of the body, the function as a retainer can work sufficiently regardless of the depth of the press fit of the seal ring.

The seal ring according to the present invention, as defined in claim 6, is the seal ring according to any one of claims 1 to 5, wherein the end of the elastic body on the external space side is abutted and regulated. A surface is provided in the hole, and at the end of the elastic body on the outer space side, a nose portion that bends inward in the radial direction and comes into close contact with the regulation surface is provided. Characterize.

According to this seal ring, when the nose portion comes into contact with the regulation surface provided in the hole and bends inward in the radial direction with the seal ring inserted in the hole, the root portion of the nose portion is accompanied by the bending. Along with the deformation, a force that spreads outward so that the large-diameter portion of the overhanging portion is brought into closer contact with the inner peripheral surface of the hole, so that the contact force of the tip-side fitting portion with respect to the hole is increased and the retaining force is increased. .

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1, 2 and 3 relate to an example of an embodiment of the present invention, and FIG. 1 shows a half of an example of a seal ring in a state where a hole and a shaft are sealed. 2 is a longitudinal sectional view of FIG.
FIG. 3 is a longitudinal sectional view showing one half of the seal ring shown in FIG. 1, and FIG. 3 is an enlarged view of a main part of the seal ring.

As shown in FIG. 1, a gasoline engine as an example of an internal combustion engine (main body not shown) is
A cylinder head cover 1 (shown by a chain double-dashed line in FIG. 1) is provided as a housing that covers the cylinder head.

Holes 10 having a circular cross section are formed in the cylinder head cover 1 so as to correspond to the number of cylinders, and a plug tube 2 as a shaft is inserted into each hole 10.

Then, the hole 10 and the plug tube 2 (see FIG.
(Indicated by a chain double-dashed line in
It is sealed as a dust seal by being partitioned by the seal ring 3 into the external space side and the sealed space side where the engine is located.

More specifically, as shown in FIG. 1, the seal ring 3 includes a metal annular core metal 4 having a flange portion 4b bent inward in the radial direction at the lower end of a cylindrical portion 4a substantially concentric with the hole 10. And an elastic body 5 made of elastic rubber, which is baked on the outer peripheral surface of the cylindrical portion 4a of the annular core metal 4 to cover the cylindrical portion 4a, and is integrally formed with the elastic body 5, and An elastic lip 6 is provided by baking on a flange portion 4b on the inner diameter side of the annular core metal 4.

The elastic lip 6 is formed with a bent portion 6a which is bent downward so that it can be expanded and contracted in the radial direction, and a tip portion 6b on the inner diameter side thereof is in close contact with the outer peripheral surface of the plug tube 2 over the entire circumference. It is provided to do.

A ring-shaped coil spring 7 for elastically urging the end portion 6b so as to contract toward the inner diameter side is provided. The coil spring 7 is fitted in an annular groove 14 formed on the outer peripheral surface of the tip portion 6b.

The elastic body 5 is, as shown in FIG.
The seal ring 3 is fitted into the hole 10 formed in the cylinder head cover 1, and the cylindrical portion 4 of the annular core metal 4 is fitted.
The outer periphery of a is covered integrally with a covering portion 8 that covers the entire circumference in the axial direction, and a protruding portion 9 that extends beyond the covering portion 8 toward the outer space.

More specifically, the hole 10 of the cylinder head cover 1 is a through hole penetrating inward and outward and having a circular cross-sectional shape, and the seal ring 3 is provided at the outer end of the hole 10.
Flange part 1 having a restriction surface 11 for restricting the position of fitting
Two are provided.

The elastic body 5 and the elastic lip 6 are integrally formed by vulcanizing and molding a rubber material.

The covering portion 8 of the elastic body 5 has an annular protruding portion M1 in which the thickness of the annular core metal 4 with respect to the cylindrical portion 4a is large.
To M3 and thin annular groove portions V1 to V3 are alternately arranged in parallel. That is, each annular ridge M
1 to M3 are formed so as to be convex outward in the radial direction over the entire circumference, that is, to have a large diameter, and the respective annular groove portions V1 to V3 are concave inward in the radial direction over the entire circumference. Is formed.

Annular raised portions M1 to M in the covering portion 8
Three 3 are provided at predetermined intervals in the press-fitting direction.

In FIG. 1, the third annular groove portion V from the bottom is shown.
The position of 3 is substantially the same as the position of the tip end side of the annular core metal 4 in the insertion direction.

A projecting portion 9 is extended in the press-fitting direction on the tip side of the annular groove portion V3, and the projecting portion 9 has an annular shape having a larger diameter radially outward than the annular groove portion V3. A raised portion M4 is formed.

Therefore, the annular ridge portion M of the elastic body 5 is
The number of 1 to M4 is four.

Then, as shown in FIG. 1, the annular ridge portion M4 provided on the projecting portion 9 is replaced by the elastic body fitting portion 9
Has become the largest in the.

Further, each of the annular raised portions M1 to M4 is constructed such that the one located closer to the tip side has a larger diameter.

That is, between the annular raised portion M1 closest to the flange portion 4b of the annular core metal 4 and the annular raised portion M4 in the protruding portion 9, each annular raised portion M1.
The outer diameters of M4 to M4 are set to gradually increase, and the outer peripheral ends of the annular raised portions M1 to M4 are the outer periphery of a virtual truncated cone (indicated by a chain line in FIG. 2) of the lower constriction in FIG. It is located almost on the plane. The two-dot chain line in FIG. 2 indicates the position of the inner peripheral surface of the hole 10.

Further, as shown in FIG. 2, the inclination angle of the outer peripheral surface of the virtual truncated cone with respect to the central axis along the vertical direction, that is, the inclination angle θ with respect to the direction along the outer periphery of the cylindrical portion 4a of the annular core metal 4 is as shown in FIG. It is 3 to 5 °.

As a result, as shown in FIG. 3, the interference L of the annular raised portions M1 to M4 with respect to the inner peripheral surface of the hole 10 is shown.
1 to L4 are larger toward the tip side. In addition,
In FIG. 3, the chain double-dashed line indicates the position of the inner peripheral surface of the hole 10.

Further, the outer space side end surface 9a of the projecting portion 9 contacts and is regulated by the position regulating surface 11 of the flange portion 12 of the hole 10 which regulates the position of the seal ring 3 in the direction of press fitting into the hole 10. .

At the outer peripheral portion of the outer space side end surface 9a of the projecting portion 9, a nose portion 13 having a triangular sectional shape and projecting toward the tip side is provided over the entire circumference.

The side surface on the inner diameter side of the nose portion 13 is a slightly concave curved surface, and the side surface on the outer diameter side is a conical surface.

Therefore, the nose portion 13 is bent toward the inner diameter side by coming into contact with the position regulating surface 11 and is deformed so that its outer peripheral side surface is slightly expanded in diameter, and the protruding portion 9 of the hole 10 with respect to the inner peripheral surface thereof is deformed. Generates a pressing force that enhances the adhesion of the.

With the above structure, the hole 10 of the projecting portion 9 is formed.
Since the fitting interference L4 (see FIG. 3) with respect to the inner peripheral surface of is larger than the fitting interferences L1 to L3 of the respective annular ridges M1 to M3 of the proximal fitting portion 8, The seal ring 3 can be fitted into the hole 10 more easily than that having a certain fitting allowance in the press-fitting direction.

The projecting portion 9 is formed by the annular core metal 4
Since the cylindrical portion 4a does not restrict the deformation toward the inner diameter side, the cylindrical portion 4a easily deforms toward the inner diameter side despite the large fitting interference L4 and easily fits into the hole 10.

Further, since the annular groove portion V3 is located at substantially the same position as the tip of the cylindrical portion 4a of the annular core metal 4,
At the time of press-fitting into the hole 10, the overhanging portion 9 having a large fitting interference L4 is more easily deformed to the inner diameter side.
Easy to fit into the hole 10.

Next, the seal ring 3 according to the embodiment.
The various evaluation tests will be described.

The inventor of the present invention, as an evaluation test of the seal ring 3, evaluates the degree of ease of press-fitting the seal ring 3 into the hole and a pre-press-fitted seal ring 3.
An outer peripheral pull-out resistance test for evaluating the degree of difficulty in pulling out and a pressure resistance / negative pressure resistance test for evaluating the pressure resistance against the internal pressure and the negative pressure resistance against the negative internal pressure of the seal ring 3 previously press-fitted were performed.

First, the outer circumference press-fitting test will be described. As shown in FIG. 4, a test jig 15 made of nylon 6 (polyamide resin) was prepared as a jig having a press-fitting hole 15a for press-fitting the seal ring 3. As the test jig 15, three kinds of jigs A, B, and C having different press-in holes 15a in inner diameter were prepared. The original standard value of the inner diameter of the press-fitting hole 15a of each test jig 15 is 41.1 mm.
However, the inner diameter is 41.45 m.
m (jig A), 41.40 mm (jig B), 41.41
mm (jig C). These inner diameter dimensions are
It was set in consideration of the variation in the measured values of the hole inner diameter in the actual housing.

Then, the seal ring 3 of the same size according to the above-described embodiment of the present invention is inserted into the insertion holes 15a of the jigs A, B and C, and the ambient temperature is kept at room temperature and the elastic body fitting portion is not covered. While the outer periphery was in a dry state, it was press-fitted by the hydraulic press 16 at a press-fitting speed of 10 mm / min while confirming that the elastic body fitting portion was not galled. The pressure input in the hydraulic press 16 at this time was detected. Specifically, the detected pressure input is 22.0 in the jig A.
N, jig B is 24.5N, jig C is 2
It was 3.6N. Therefore, the pressure input is relatively small.

Next, the outer peripheral pull-out resistance test will be described. The seal ring is preliminarily press-fitted into the jigs A, B, and C while the ambient temperature is room temperature and the outer periphery of the elastic fitting portion is dry. Then, as shown in FIG.
Each jig A, B, C is turned upside down and placed on the abutment 17,
Immediately after being press-fitted, left for 100 hours at an ambient temperature of 130 ° C, 3 at an ambient temperature of 130 ° C
What was left for 00 hours, 500 at an ambient temperature of 130 ° C
The ones left for 4 hours and the ones under 4 kinds of conditions are placed on the abutment 17 with the jigs A, B and C turned upside down, and the seal ring 3 is pulled out by the hydraulic press 16. A downward pressing force was applied, and the load at the time of removal was obtained as shown in Table 1. In addition, creep 100h in Table 1
Indicates that the product was left to stand for 100 hours at an ambient temperature of 130 ° C., and new means that that was just after the seal ring 3 was press-fitted.

[0060]

[Table 1] As a result, the withdrawal resistance gradually decreases as it is left for a long time at an ambient temperature of 130 ° C.

Next, the pressure resistance / negative pressure resistance test will be described. As shown in FIG. 6, as a jig having a press-fitting hole 18a for press-fitting the seal ring and a cylindrical portion 18b corresponding to the shaft-like body with which the elastic lip 6 of the seal ring 3 comes into close contact, A test jig 18 made of 6 (polyamide resin) was prepared. Press-fitting hole 18a of this jig 18
Since the inner diameter of the seal is set to a standard value of 41.1 mm, an air compressor (not shown) can change the inner pressure in the inner space into which the seal ring 3 is press-fitted.
Is configured so that air can be supplied or sucked through the valve 19 and the pressure gauge 20.

Then, the seal ring 3 is press-fitted at a constant position in the depth direction of the jig 18 at room temperature, and immediately after the fitting, 100 is placed in a constant temperature bath 21 at 130 ° C. after fitting. After being left in the atmosphere of 130 ° C. for an additional hour, the valve 19 is opened to apply an arbitrary internal pressure, and then the valve 19 is closed for 10 minutes. After a lapse of time, the detected value of the pressure gauge 19 is read to determine whether or not there is air leakage. As a result, Table 2 shows the critical pressure at which air leakage does not occur.
Obtained as shown in Table 3. Table 2 shows the pressure resistance test results, and Table 3 shows the negative pressure resistance test results.

[0063]

[Table 2]

[Table 3] Therefore, it was confirmed that the pressure resistance of the seal ring 3 according to the above-mentioned embodiment is lowered from the creep time of 300 hours, and air leakage occurs from the outer peripheral portion of the seal. As a result of re-measurement of the dimensions, it was found that when the creep time is long, the inner diameter of the press-fitting hole 18a of the jig 18 becomes large and the fitting interference of the seal ring 3 becomes somewhat small. This was particularly affected by the increase in the inner diameter of the press-fitting hole 18a of the jig 18. On the other hand, the negative pressure resistance of the seal ring 3 was good with no deterioration even after the creep time of 500 hours.

(Another Embodiment) The present invention may be implemented as follows. The description of the same structure as that of the above-described embodiment will be omitted and the same reference numerals will be given.

(1) As shown in FIG. 7, the seal ring 3
Is an elastic lip 6 that closely contacts the outer peripheral surface of the plug tube 2.
The coil spring 7 provided at the tip portion 6a of the above is embedded in the elastic lip 6.

(2) As shown in FIG. 8, the seal ring 3
The elastic body 5 has a constant thickness in the press-fitting direction on the outer peripheral surface of the covering portion 8 attached so as to cover the outer peripheral surface of the annular core metal 4. A large-diameter portion 21 having a diameter larger than the outer peripheral diameter of the covering portion 8 is provided in the protruding portion 9 extending toward the distal end side of the covering portion 8 in the press-fitting direction, that is, the outer space side. Therefore, the large-diameter portion 21 has a larger fitting interference with respect to the hole 10 than the covering portion 8. (3) As shown in FIG. 9, an annular raised portion 22 is provided on the outer periphery of the overhanging portion 9 of the elastic body 5 of the seal ring 3 and forms a ridge having a diameter larger than the outer diameter of the covering portion 8. An annular recessed groove 23 is formed as an annular groove portion at a position where the covered portion 8 transitions to the projecting portion 9, that is, at the outer peripheral portion of the covered portion 8 near the tip end position of the cylindrical portion 4a of the annular core metal 4 in the press-fitting direction. ing. Therefore, due to the annular raised portion 22, the fitting interference when press-fitting into the hole of the projecting portion 9 is larger than that of the covering portion 8. Further, the recessed groove 23 makes it easy for the protruding portion 9 to be deformed toward the inner diameter side when being pressed into the hole.

[0067]

As described above, according to the present invention, even if the housing is molded and the like, and the hole is not processed to improve the dimensional accuracy, the seal ring is formed into the hole. If there is a part where the fitting interference is large, there is a large misalignment between the hole and the shaft, and if the hole size changes somewhat due to temperature, Due to the interference portion, a gap is less likely to be formed between the hole and the elastic body fitting portion, and the sealing performance is high.

Further, although there is some resistance when the portion of the elastic body that overhangs in the external space with a large fitting margin is press-fitted, the covered portion covered with the annular core metal fits more than the overhanged portion. Because the interference is small,
It is easier to insert than the conventional one, which has a fixed fitting allowance in the press-fitting direction.

Further, in the elastic body, the overhanging portion having a large fitting interference mainly exerts a force of closely adhering to the hole in the radial direction, so that the force sufficiently functions as a retainer.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of one half showing an example of a seal ring in a state where a hole and a shaft are sealed.

FIG. 2 is a longitudinal sectional view showing one half of the seal ring shown in FIG.

FIG. 3 is a vertical sectional view showing a main part of a seal ring.

FIG. 4 is an explanatory diagram showing an outer circumference press-fitting test.

FIG. 5 is an explanatory diagram showing an outer periphery pullout resistance test.

FIG. 6 is an explanatory diagram showing a pressure resistance / negative pressure resistance test.

FIG. 7 is a longitudinal sectional view showing one half of a seal ring according to another embodiment.

FIG. 8 is a vertical cross-sectional view showing one half of a seal ring according to another embodiment.

FIG. 9 is a longitudinal sectional view showing one half of a seal ring according to another embodiment.

[Explanation of symbols]

1 Cylinder head cover (housing) 3 seal ring 4 Ring core 5 elastic body 6 elastic lip 8 Covered part 9 Overhanging part 10 holes 11 Regulatory aspects 13 Nose part M1-M4 annular ridge V1-V3 annular groove part

Continued front page    F-term (reference) 3J006 AE14 AE30 AE39 AE41                 3J040 BA03 EA01 EA15 EA17 EA42                       FA01 FA05 HA16

Claims (6)

[Claims] 1. A seal ring for partitioning an annular space formed between a housing having a hole and a shaft-shaped body inserted into the housing in a non-contact state into an external space side and a sealed space side, the ring being substantially the same as the hole. An annular core metal having a concentric cylindrical portion, an elastic body which is attached in a state of covering the outer periphery of the cylindrical portion of the annular core metal and is pressed against the inner peripheral surface of the hole of the housing, and the annular core metal An elastic lip that is attached to the inner diameter side and is brought into contact with the outer peripheral surface of the shaft-shaped body, wherein the elastic body is projected toward the outer space side with respect to the annular core metal, and this protruding portion And a fitting interference with respect to the inner peripheral surface of the hole of the housing is set to be larger than a fitting interference with respect to the inner peripheral surface of the hole of the housing in the covering portion of the elastic body that covers the outer periphery of the annular core metal. There is a seal Ring. 2. The seal ring according to claim 1, wherein the elastic body is provided on its outer periphery with annular ridges having large diameters at predetermined axial intervals. 3. The seal ring according to claim 1 or 2, wherein an annular groove is provided on the outer periphery of the elastic body near the outer space side end of the annular core. Seal ring. 4. The seal ring according to claim 2, wherein three or more annular ridges are provided. 5. The seal ring according to any one of claims 1 to 4, wherein a fitting interference of the annular ridge portion with respect to an inner peripheral surface of the hole is larger as it is closer to the projecting portion. A seal ring characterized by being set. 6. The seal ring according to any one of claims 1 to 5, wherein the hole is provided with a restriction surface on which the end of the elastic body on the outer space side is abutted and restricted. A seal ring, characterized in that a nose portion is provided at an end portion on the space side, the nose portion being bent inward in a radial direction when being in contact with the regulation surface and being in close contact with the regulation surface.