JP7365881B2 - Seal ring - Google Patents

Description

The present invention is intended for sealing fluid in devices that utilize the fluid pressure of fluids such as hydraulic oil, such as automatic transmissions (hereinafter referred to as AT) and continuously variable transmissions (hereinafter referred to as CVT). Concerning the seal ring used.

In equipment such as ATs and CVTs, oil seal rings are installed at key points to seal hydraulic oil. For example, the seal ring is attached to a pair of spaced apart annular grooves provided on the rotating shaft that is inserted into the shaft hole of the housing, and the hydraulic oil supplied from the oil passage between the two annular grooves is supplied to the side and inner peripheral surfaces of both seal rings. The side wall of the annular groove and the inner circumferential surface of the housing are sealed by the opposite side surface and outer circumferential surface. Each sealing surface of the seal ring is in sliding contact with the side wall of the annular groove and the inner circumferential surface of the housing, respectively, and maintains the hydraulic pressure of the hydraulic oil between both seal rings.

Conventionally, as such a seal ring, a seal ring made of synthetic resin obtained by injection molding is known (see, for example, Patent Document 1). This seal ring is an annular body with a substantially rectangular cross section, and has an abutment at one location in the circumferential direction. The abutment is composed of a pair of ends that fit in a complementary manner. For example, one abutment has an abutment surface on the inner diameter side of the seal ring, and a lip protruding from the abutment surface and a retracted lip on the outer diameter side. and a pocket, and the other abutment employs a compound step-cut abutment having an abutting surface, a pocket, and a lip formed to complementarily fit with the abutting surface, the lip, and the pocket. has been done.

Japanese Patent Application Publication No. 09-100919

A seal ring made of synthetic resin obtained by injection molding expands in diameter by elastic deformation and is installed in the annular groove of the rotating shaft, and then assembled into the inner diameter of the housing. FIG. 12 shows a state in which a rotary shaft 61 equipped with a conventional seal ring 51 is assembled into a housing 62. As shown in FIG. 12, the rotating shaft 61 is inserted into the housing 62 from one end side and assembled. A tapered portion 62a is formed at the open end of the housing 62. However, due to eccentricity or the like, the outer circumferential surface of the seal ring 51 may be located on the radially outer side than the tapered portion 62a of the housing 62. In such a case, the ring side surface 52 of the seal ring 51 comes into contact with the end surface 62b of the housing, which may cause problems such as galling in the seal ring 51.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a seal ring that can suppress the occurrence of galling when assembling a housing, and can maintain low oil leakage.

The seal ring of the present invention is installed in an annular groove provided on a rotating shaft inserted into an axial hole of a housing, slidably contacts a side wall surface of the annular groove on the non-sealed fluid side, and A seal ring that contacts the inner peripheral surface of the hole to seal the annular gap between the rotating shaft and the shaft hole, the seal ring is an injection molded product of a resin composition, and the outer peripheral surface of the seal ring is an injection molded body of a resin composition. At least one end side is provided with an inclined portion, and the inclined portion has an inclined surface connected to the ring side surface and a stepped surface connected substantially perpendicularly to the outer circumferential surface, and the stepped surface in the ring radial direction. It is characterized by a width of 0.1 mm or less.

The inclined portion is characterized by having a connection surface that is substantially perpendicular to the ring side surface and connects the inclined surface and the stepped surface. Further, the stepped surface is located inside in the ring radial direction from a virtual plane that is an extension of the inclined surface.

In the axial cross section of the seal ring, the inclined surface has an inclination angle of 20 degrees to 60 degrees with respect to the outer circumferential surface.

The seal ring is characterized in that it has a composite step-cut abutment in a part of its circumferential direction.

The resin composition is characterized in that the base resin is a polyetherketone (PEK) resin, a polyetheretherketone (PEEK) resin, a polyphenylene sulfide (PPS) resin, or a polyamideimide (PAI) resin.

The seal ring of the present invention is an injection molded product of a resin composition, and includes an inclined portion on at least one end side of the outer circumferential surface, and the inclined portion includes an inclined surface connected to the side surface of the ring and a substantially perpendicular to the outer circumferential surface. The width of the stepped surface in the ring radial direction is 0.1 mm or less, so when inserting and assembling the seal ring into the housing, the stepped surface on the outer diameter side of the housing It is possible to suppress the contact with the end face and prevent the occurrence of galling. This prevents scratches such as dents on the sealing surface on the side surface of the ring, thereby maintaining low oil leakage of the seal ring.

The sloped portion is approximately perpendicular to the side surface of the ring and has a connection surface that connects the sloped surface and the stepped surface, so when the sloped portion of the seal ring is inserted against the tapered portion of the housing, the stepped surface Hitting the end face can be further suppressed. Furthermore, since the step surface is located inside the radial direction of the ring than the imaginary plane that is an extension of the inclined surface, the boundary between the step surface and the outer peripheral surface does not protrude from the imaginary plane, and even if the end surface of the housing hits it, it will not be galled. can be prevented from occurring.

In the axial cross section of the seal ring, the angle of inclination of the inclined surface with respect to the outer peripheral surface is 20 degrees to 60 degrees, so even if the seal ring is eccentric to the rotating shaft or the end surface of the housing hits it, The occurrence of galling can be suppressed.

Since the seal ring has a composite step-cut joint in a part of the circumferential direction, it has particularly excellent oil sealing properties. In addition, since the base resin of the resin composition is PEK resin, PEEK resin, PPS resin, or PAI resin, it has excellent bending elastic modulus and heat resistance, and does not crack even if the diameter is expanded when incorporating it into the groove. Can be used even when the temperature of the hydraulic oil being sealed is high.

FIG. 2 is a plan view showing an example of a seal ring of the present invention. 2 is a cross-sectional view and a partially enlarged view of the seal ring in FIG. 1. FIG. FIG. 3 is a diagram for explaining the positional relationship between an inclined surface and a stepped surface. FIG. 7 is a cross-sectional view and a partially enlarged view of another example of the seal ring of the present invention. FIG. 2 is a diagram showing a state when the seal ring of FIG. 1 is assembled into a housing. FIG. 2 is a sectional view showing a state in which the seal ring of FIG. 1 is assembled into an annular groove. FIG. 3 is a cross-sectional view of a molding die during injection molding. It is a sectional view showing a mold release process. FIG. 4 is a cross-sectional view of seal rings of Examples 1 to 4. 3 is a cross-sectional view of seal rings of Comparative Examples 1 and 2. FIG. FIG. 3 is a schematic diagram of a test for measuring the amount of oil leak from a seal ring. It is a figure which shows the state when assembling a conventional seal ring to a housing.

An example of the seal ring of the present invention will be explained based on FIGS. 1 and 2. FIG. 1 is a plan view of the seal ring, FIG. 2(a) is a sectional view taken along line AA, and FIG. 2(b) is a partially enlarged view thereof. As shown in FIG. 1, the seal ring 1 is an annular body having a substantially rectangular cross section formed by injection molding using a mold. The seal ring 1 is a cut-type ring having an abutment 10 at one location in the circumferential direction, expands in diameter by elastic deformation, and is mounted in an annular groove. The abutment 10 is composed of a pair of ends. Regarding the shape of the pair of ends, it is possible to make a straight cut, an angle cut, etc., but it is preferable to adopt a compound step cut shown in FIG. 1 because it has excellent oil sealing properties.

The size of the seal ring (outer diameter φ, inner diameter φ, ring width (radial length), ring thickness (axial length), etc.) is appropriately set depending on the application and the like. For example, the inner diameter φ of the seal ring is 9 mm to 75 mm, and the outer diameter φ is 13 mm to 80 mm.

In the seal ring 1, the ring side surface 4 serves as a sliding surface against the side wall surface of the annular groove. As shown in FIG. 2(a), a step portion 5 is provided at the corner of the ring inner circumferential surface 2 and the ring side surface 4, which becomes a protruding portion from the mold during injection molding. In FIG. 2(a), the stepped portions 5 are provided on both sides. Further, an inclined portion 6 is provided at a corner between the ring outer circumferential surface 3 and the ring side surface 4. The inclined portion 6 serves as a non-contact portion with the side wall surface of the annular groove over the entire circumference of the ring. In addition, a plurality of lubricating grooves consisting of recesses may be formed at the inner diameter end of the ring side surface 4 so as to be spaced apart in the circumferential direction.

The inclined portion 6 will be further explained. As shown in FIG. 2(b), the inclined portion 6 has an inclined surface 7 connected to the ring side surface 4, a stepped surface 8 connected perpendicularly to the ring outer peripheral surface 3, and a connecting surface 9. . In the present invention, the stepped surface 8 is a surface formed by splitting a mold (also referred to as a splitting surface). When the seal ring 1 is provided with the sloped part 6, if the mold parting surface is placed on the extension line of the ring side surface 4, the sloped part 6 will become an undercut when the mold is released from the mold, and the molded product will be damaged. Difficult to remove from mold. Therefore, in the present invention, the mold cutting surface of the mold is arranged on an extension of the stepped surface 8 of the seal ring. In addition, the width W _a of the step surface 8 in the ring radial direction is set to 0.1 mm or less. By reducing the mold separation step in this way, problems such as galling of the seal ring are prevented. In particular, the width W _a is preferably 0.01 mm to 0.05 mm.

The seal ring 1 shown in FIG. 2 has sloped portions on both sides of the ring outer peripheral surface 3. The seal ring 1 shown in FIG. Among the sloped parts on both sides, one sloped part (slanted part 6) has a stepped surface 8, and the other sloped part is composed of only a sloped surface. The stepped surface 8 may be formed on at least one sloped portion, but may be formed symmetrically on both sloped portions. In this case, the sloped portions on both sides have a stepped surface, eliminating dependence on the assembly direction.

The depth of the inclined surface 7 from the sliding surface increases toward the outside in the ring radial direction, and is constant in the ring axial direction. In the axial cross section of the seal ring 1, the inclination angle α (see FIG. 2(a)) of the inclined surface 7 with respect to the ring outer peripheral surface 3 is, for example, 20 degrees to 60 degrees. The inclination angle α is preferably 30 degrees to 50 degrees, more preferably 30 degrees to 45 degrees, and still more preferably 40 degrees to 45 degrees. If the inclination angle α is less than 20 degrees, if the seal ring is eccentric (protrudes from the annular groove) to a large extent, it will tend to hit the end face of the housing, which may cause galling. Furthermore, if the inclination angle α exceeds 60 degrees, the seal ring will not be smooth when it hits the end face of the housing, and will tend to catch on the step surface 8, which may cause slight galling.

Furthermore, in the seal ring 1 shown in FIG. 2, a connecting surface 9 perpendicular to the ring side surface 4 is provided between the inclined surface 7 and the stepped surface 8. Providing the connecting surface 9 makes it easier to accommodate the stepped surface 8 within the inclined portion. Note that the connecting surface 9 only needs to be a surface substantially perpendicular to the ring side surface 4, and may be a flat surface or a curved surface. Although the thickness T of the connecting surface 9 in the ring axial direction is not particularly limited, it is preferably larger than the width W _a of the stepped surface 8. As a specific dimension, the thickness T is preferably 0.05 mm to 0.3 mm, for example. More preferably, it is 0.05 mm to 0.1 mm.

In FIG. 3(a), the positional relationship between the inclined surface and the stepped surface will be explained. As shown in FIG. 3A, if F is a virtual plane obtained by extending the inclined surface 7, the stepped surface 8 is located inside the virtual plane F in the ring radial direction. In other words, the corner P that is the boundary between the outer circumferential surface 3 and the stepped surface 8 does not protrude radially outward from the virtual plane F. By placing the stepped surface 8 on the inside of the inclined portion in this way, even when the inclined surface 7 is pressed against the tapered portion of the housing, the stepped surface 8 (including the corner P) is prevented from hitting the end surface of the housing. This can prevent galling.

FIG. 3(b) shows a modification of the stepped surface of the inclined portion. As shown in FIG. 3(b), the stepped surface 8' is formed as a curved surface substantially perpendicular to the outer circumferential surface 3, and the boundary between the outer circumferential surface 3 and the stepped surface 8 is formed in an R shape. The stepped surface 8' can be obtained, for example, by polishing the corner P shown in FIG. 3(a) by barrel polishing or the like. By making the boundary part rounded, galling of the stepped surface 8' can be further prevented. Note that also in the modification shown in FIG. 3(b), the stepped surface 8' is located inside the virtual plane F in the ring radial direction.

Another example of the seal ring of the present invention is shown in FIG. FIG. 4(a) is a sectional view of the seal ring, and FIG. 4(b) is a partially enlarged view thereof. The seal ring 11 differs from the seal ring 1 of FIG. 1 in the configuration of the inclined portion. Specifically, as shown in FIG. 4(b), the inclined portion 16 has an inclined surface 17 connected to the ring side surface 14 and a stepped surface 18 connected perpendicularly to the ring outer peripheral surface 13. . Also in this embodiment, the width W _a of the stepped surface 18 in the ring radial direction is 0.1 mm or less, preferably 0.01 mm to 0.05 mm. Note that a preferable range of the inclination angle β (see FIG. 4(a)) of the inclined surface 17 is the same as the range of the inclination angle α of the inclined surface 7 described above.

FIG. 5 shows the state when the housing is assembled. In FIG. 5, the seal ring 1 and the housing 22 are shown in cross section. The seal ring 1 is first expanded in diameter using a jig (not shown) and then installed in the annular groove 21a of the rotating shaft 21. With the seal ring 1 attached, the rotating shaft 21 is inserted into the housing 22 and assembled. As shown in FIG. 5, a tapered portion 22a consisting of an inclined surface (for example, an inclined angle of 30 degrees to 50 degrees) is provided at the open end of the housing. However, if the wall thickness of the housing is small or if a sufficient taper cannot be formed to prevent interference with the seal ring, the outer peripheral surface of the seal ring may be located outside the tapered part of the housing due to eccentricity. Sometimes. In such a case, the side surface of the seal ring may come into contact with the end surface of the housing, causing galling (see FIG. 12).

As shown in FIG. 5(b), the seal ring according to the present invention has an inclined portion having the above-mentioned inclined surface 7 and step surface 8 formed on one end side of the ring outer circumferential surface 3, so that the seal ring Even if the amount of eccentricity becomes large, it is easy to fit the inclined angle part 6a, which is the boundary between the ring side surface 4 and the inclined surface 7, into the tapered part 22a of the housing 22. Since the housing 22 can be easily positioned inside the diameter R and the width of the step surface 8 is small, it is possible to suppress the end surface 22b of the housing 22 from coming into contact with the step surface 8, thereby preventing galling.

In order to accommodate the inclined angle portion 6a of the seal ring 1 within the tapered portion 22a of the housing 22, the inclined dimension _Wb of the seal ring 1 is set. The inclination dimension _Wb is the distance from the ring outer circumferential surface 3 to the inclination corner part 6a in the ring radial direction, and is the outer diameter φ in the free state of the seal ring 1, the ring thickness W, the depth h of the annular groove, and the taper of the housing. It is set based on the diameter R and the maximum eccentricity due to drop during assembly. The ring thickness W is the distance from the ring outer peripheral surface 3 to the ring inner peripheral surface 2, and the depth h of the annular groove is the radial length from the outer peripheral end surface of the rotating shaft 21 to the bottom of the annular groove 21a. The tapered portion diameter R of the housing is the outer circumferential diameter of the tapered portion 22a of the housing 22. Here, the maximum eccentricity is the maximum value of the distance by which the opposite side protrudes from the annular groove when the seal ring falls into the annular groove. When each dimension (outer diameter φ, W, h, R) changes, the maximum eccentricity is the maximum value of the outer diameter φ, the minimum value of the ring thickness W, and the maximum value of the annular groove depth h. This value is set using the minimum value of the taper portion diameter R. With this setting, even when the seal ring 1 is at its maximum eccentricity, the inclined angle part 6a of the seal ring 1 can be positioned within the tapered part 22a of the housing 22, and the seal ring can be inserted smoothly. can.

An outline of how the seal ring is used will be explained based on FIG. 6. The seal ring 1 is installed in an annular groove 21a provided in a rotating shaft 21 that is inserted into a shaft hole 22c of the housing. The arrow in the figure is the direction in which pressure from the hydraulic oil is applied, and the right side in the figure is the non-sealed fluid side. The seal ring 1 has its ring side surface 4 in slidable contact with the side wall surface 21b of the annular groove 21a on the non-sealed fluid side. Further, the outer circumferential surface 3 is in contact with the inner circumferential surface of the shaft hole 22c. This seal structure seals the annular gap between the rotating shaft 21 and the shaft hole 22c. Further, the type of hydraulic oil is appropriately used depending on the purpose. For example, it is used under conditions such as an oil temperature of about -30 to 150°C, an oil pressure of about 0 to 3.0 MPa, and a rotating shaft rotation speed of about 0 to 7000 rpm.

The seal ring of the present invention is an injection molded article of a resin composition. As the base resin of the resin composition, any synthetic resin that can be injection molded can be used. For example, thermoplastic polyimide resin, PEK resin, PEEK resin, PPS resin, PAI resin, polyamide (PA) resin, polybutylene terephthalate (PBT) resin, polyethylene terephthalate (PET) resin, polyethylene (PE) resin, polyacetal (POM) resin, phenol (PF) resin, etc. Note that these resins may be used alone or as a polymer alloy in which two or more types are mixed. Among these resins, it is particularly preferable to use PEK resin, PEEK resin, PPS resin, or PAI resin as the base resin because they are excellent in frictional wear characteristics, flexural modulus, heat resistance, sliding properties, etc. These resins have a high modulus of elasticity, are difficult to break even when expanded in diameter when incorporated into an annular groove, can be used even when the temperature of the hydraulic oil to be sealed is high, and there is no worry of solvent cracks.

In addition, if necessary, fibrous reinforcing materials such as carbon fiber, glass fiber, and aramid fiber, spherical fillers such as spherical silica and spherical carbon, scaly reinforcing materials such as mica and talc, and potassium titanate whiskers may be added to the base resin as necessary. It is possible to incorporate microfiber reinforcing materials such as Further, solid lubricants such as polytetrafluoroethylene (PTFE) resin, graphite and molybdenum disulfide, sliding reinforcing materials such as calcium phosphate and calcium sulfate, and pigments such as carbon black can also be blended. These can be blended alone or in combination.

The above raw materials are melt-kneaded to form pellets for molding, which are then molded into a predetermined shape by injection molding. FIG. 7 shows a cross-sectional view of the molding die. As shown in FIG. 7, the molding die includes a fixed die 23, a movable die 24, and a core pin 25. In the molding die, a cavity 26 is formed by the fixed side die 23 and the movable side die 24 that are brought into contact with each other at the abutment surface PL, and the core pin 25 . The resin composition in a molten state is filled into the cavity 26, and after being kept under pressure, it is cooled for a certain period of time to obtain a molded body 27. The inclined portion including the stepped surface 27 a of the molded body 27 is formed by the stationary mold 23 . On the abutment surface PL, the end of the fixed mold 23 (PL surface on the outer circumferential side of the seal ring) is directed toward the cavity 26 than the end of the movable mold 24 (PL surface on the outer circumferential side of the seal ring). This protrudes, and the difference in the position of this end portion creates a mold dividing step (step surface 8).

Subsequently, the fixed side mold and the movable side mold are opened to take out the molded body. In FIG. 8, the mold release process is shown step by step. In FIG. 7(a), the stationary mold 23 and the movable mold 24 are separated at their abutting surfaces. After the mold is opened, the core pin 25 moves forward toward the stationary mold 23, so that the molded body 27 is released from the movable mold 24 (FIG. 7(b)). The step 25a of the core pin 25 forms a step at the inner diameter end of the seal ring. As shown in FIG. 7(c), the core pin 25 moves further forward, and the molded body 27 is taken out from the molding die. The abutment of the molded body 27 taken out has a pair of ends separated from each other, but is closed by heat setting or the like to obtain a seal ring 1 as shown in FIG. 1.

Examples 1 to 4
Seal rings having the respective shapes shown in FIG. 9 were manufactured by injection molding using a resin composition containing PEEK resin as a base resin, carbon fiber and PTFE resin. The dimensions of the seal rings of Examples 1 to 4 are an outer diameter of 32 mm, an inner diameter of 28 mm, a ring width (radial length) of 2 mm, and a ring thickness (axial length) of 2.3 mm. The seal ring of each example is formed with an inclined portion having an inclined surface 7, a stepped surface 8, and a connecting surface 9. The width W _a (see FIG. 2) of the stepped surface is 0.05 mm, and the connecting surface is The thickness T (see FIG. 2) is 0.08 mm. The inclination angles θ of the inclined surfaces are different, and are 40 degrees in Example 1, 30 degrees in Example 2, 60 degrees in Example 3, and 20 degrees in Example 4. Further, the slope portion dimension W _b (see FIG. 5) of each seal ring is 0.4 mm.

Comparative example 1
A seal ring having the shape shown in FIG. 10 was manufactured by injection molding using a resin composition containing PEEK resin as a base resin, carbon fiber and PTFE resin. The dimensions of this seal ring are an outer diameter of 32 mm, an inner diameter of 28 mm, a ring width of 2 mm, and a ring thickness of 2.3 mm.

Comparative example 2
A seal ring having the shape shown in FIG. 10 was manufactured by injection molding using a resin composition containing PEEK resin as a base resin, carbon fiber and PTFE resin. The dimensions of this seal ring are an outer diameter of 32 mm, an inner diameter of 28 mm, a ring width of 2 mm, and a ring thickness of 2.3 mm. The seal ring of Comparative Example 2 has inclined portions formed on both sides of the outer peripheral surface. This inclined portion has a shape in which a surface connected perpendicularly to the side surface of the ring and a surface connected perpendicularly to the outer circumferential surface of the ring are connected by an inclined surface. The dimension W _b of the inclined portion is 0.4 mm, and the width W _a of the surface corresponding to the stepped surface according to the present invention is 0.2 mm.

<Integration test>
The assemblability of each of the obtained seal rings was evaluated. As shown in FIG. 5, each seal ring was attached to the annular groove (depth h2.2 mm) of the rotating shaft and inserted into a housing (tapered portion diameter R34.5 mm, tapered portion inclination angle 45 degrees). For each seal ring, the degree of eccentricity was changed and the ease of assembly was evaluated in four stages (A to D). The evaluation was rated A when there was no galling, B when the galling was minute, C when the galling was small, and D when the galling was large. The results are shown in Table 1.

As shown in Table 1, when there was no eccentricity, galling did not occur in any of the seal rings, but there was a tendency for the degree of galling to increase as the amount of eccentricity increased. When the eccentricity was 0.6 mm, almost no galling was observed in Examples 1 to 4, whereas large galling was observed at the corners P in Comparative Examples 1 to 2. . In Comparative Example 2, an inclined portion was formed, and although the inclined corner portion Q was located within the tapered portion of the housing, galling occurred because the width W _a of the step surface including the corner portion P was large. Among Examples 1 to 4, the seal rings in which the inclined surface 7 has an inclination angle of 40 degrees (Example 1) and 30 degrees (Example 2) are particularly effective even when the eccentricity is as large as 0.7 mm. Almost no gnawing was observed. In this case, the seal ring of Example 3 (inclination angle θ = 60 degrees) was a little stuck on the stepped surface, and small galling occurred.

<Oil leak test>
The amount of oil leak from each seal ring obtained was evaluated using a testing machine shown in FIG. 11. FIG. 11 is a schematic diagram of the testing machine. Seal rings 30, 30' were attached to the annular groove of the mating shaft 28. A seal ring before the above-mentioned assembly test and a seal ring after the above-mentioned assembly test (eccentricity 0.7 mm) were used as the seal rings, respectively. As the motor 31 rotates, the seal rings 30 and 30' come into sliding contact with the annular groove side wall of the mating shaft 28 and the inner peripheral surface of the shaft hole of the housing 29. Oil was pumped from the hydraulic unit 32 and supplied to the annular gap between the seal rings 30 and 30'. The conditions for the oil leak test were a hydraulic pressure of 800 kPa, a rotation speed of 2000 rpm, and an oil temperature of 80° C., and ATF was used as the oil. The amount of oil leak (ml/min) was measured using this testing machine. The oil leak amount is based on the value measured 5 minutes after the start of the test. The results are shown in Table 2.

As shown in Table 2, before the installation test, all test examples showed almost the same amount of oil leakage. On the other hand, after the installation test, in Examples 1 and 2, almost no change was observed in the amount of oil leakage. As mentioned above, since almost no galling occurred, low oil leakage was maintained even after installation. On the other hand, in Comparative Examples 1 and 2, the amount of oil leakage significantly increased due to installation. It is thought that these seal rings had a large amount of galling during installation, which led to a decrease in sealing performance with the side wall surface and shaft hole. Although Examples 3 and 4 also resulted in an increase in the amount of oil leakage, it is thought that depending on the amount of eccentricity (for example, eccentricity of 0.6 mm), low oil leakage property can be maintained.

The seal ring of the present invention can suppress the occurrence of galling when assembling the housing and can maintain low oil leakage, so it can be used as a seal ring that requires low oil leakage between the rotating shaft and the housing. In particular, it can be suitably used in hydraulic equipment such as ATs and CVTs in automobiles to improve fuel efficiency.

1 Seal ring 2 Inner circumferential surface of ring 3 Outer circumferential surface of ring 4 Side surface of ring 5 Step portion 6 Inclined portion 7 Inclined surface 8, 8' Step surface 9 Connection surface 10 Abutment 11 Seal ring 12 Inner circumferential surface of ring 13 Outer circumferential surface of ring 14 Ring Side surface 15 Step portion 16 Inclined portion 17 Inclined surface 18 Step surface 21 Rotating shaft 22 Housing 23 Fixed side mold 24 Movable side mold 25 Core pin 26 Cavity 27 Molded body 28 Mating shaft 29 Housing 30, 30' Seal ring 31 Motor 32 Hydraulic pressure unit

Claims (5)

It is attached to an annular groove provided in a rotating shaft that is inserted into an axial hole of a housing, and slidably contacts the side wall surface of the annular groove on the non-sealed fluid side, and also contacts the inner circumferential surface of the axial hole. A seal ring for sealing an annular gap between the rotating shaft and the shaft hole,
The seal ring is an injection molded body of a resin composition, and includes an inclined portion on one end side or both end sides of the outer peripheral surface,
At least one of the inclined portions includes an inclined surface connected to a side surface of the ring, a stepped surface connected substantially perpendicularly to the outer peripheral surface, and a stepped surface substantially perpendicular to the ring side surface that connects the inclined surface and the stepped surface. A seal ring having a connecting surface , the step surface having a width of 0.1 mm or less in the ring radial direction. 2. The seal ring according to claim 1 , wherein the stepped surface is located inside in the ring radial direction from a virtual plane that is an extension of the inclined surface. 3. The seal ring according to claim 1 , wherein in an axial cross-section of the seal ring, an inclination angle of the inclined surface with respect to the outer circumferential surface is 20 degrees to 60 degrees. 4. The seal ring according to claim 1 , wherein the seal ring has a composite step-cut abutment in a part of the circumferential direction. The base resin of the resin composition is a polyetherketone resin, a polyetheretherketone resin, a polyphenylene sulfide resin, or a polyamideimide resin, according to any one of claims 1 to 4 . Seal ring.

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