JP2020106134A - Seal ring - Google Patents

Abstract

To provide a seal ring having both low-oil leak performance which is an original purpose of the seal ring, and low-torque performance for an improvement of fuel economy in a balanced manner.SOLUTION: A seal ring 1 is attached to a housing having a shaft hole, and to an annular groove which is formed at one member of a rotating shaft inserted into the shaft hole, contacts with a surface of the other member, also slidably contacts with a sidewall face of the annular groove at a non-sealing fluid side, and seals an annular clearance between and among these items. A recess 3 being a non-contact part not contacting with the sidewall face is formed at a part of a ring side face 2 being a slide face sliding with at least the sidewall face at an inside-diameter side end part, and the recess 3 has a pair of flat faces forming a V-shape along a ring peripheral direction, and an inclination flat face connected to the pair of flat faces, and inclined along a ring radial direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to an automatic transmission (hereinafter referred to as AT), a continuously variable transmission (hereinafter referred to as CVT), and other devices that utilize the fluid pressure of a fluid such as hydraulic fluid to seal the fluid. Regarding the seal ring used.

In equipment such as AT and CVT, an oil seal ring for sealing the working oil is attached at a required position. For example, operating oil supplied from an oil passage between a pair of spaced apart annular grooves provided on a rotary shaft that is inserted into a shaft hole of a housing is supplied to side surfaces and inner peripheral surfaces of both seal rings. The side wall on the opposite side and the outer peripheral surface seal the side wall of the annular groove and the inner peripheral surface of the housing. Each seal surface of the seal ring holds the hydraulic pressure of the hydraulic oil between the seal rings while making sliding contact with the side wall of the annular groove and the inner peripheral surface of the housing. Such a seal ring is required to have low friction loss and sufficient oil sealability. Particularly in recent years, improvement of fuel consumption has become an important issue, and in devices such as AT and CVT, further improvement of low torque property is desired while maintaining good sealability.

Conventionally, as such a seal ring, a seal ring of Patent Document 1 as shown in FIG. 8 has been proposed. FIG. 8 is a partially cutaway view of the seal ring. As shown in FIG. 8, in this seal ring, a flow path for introducing a fluid to be sealed is formed in a sliding surface 21 of the ring, and a projection 23 (a recess 22 on both sides of the projection is formed in the middle of the flow path). ) Is provided to generate the dynamic pressure so as to reduce the surface pressure between the sliding surfaces.

Further, as another seal ring, a seal ring of Patent Document 2 as shown in FIG. 9 has been proposed. FIG. 9 is a view showing a state in which the seal ring is attached to the annular groove. As shown in FIG. 9, this seal ring is attached to the annular groove 31, and has a concave portion at the end of the sliding surface 32 on the non-contact portion 33 side, in which the edge of the end is partially cut out. 34 are provided.

JP-A-8-121603 JP, 2008-275052, A

However, although the seal ring of Patent Document 1 can be expected to have an oil film forming effect due to dynamic pressure at high speed rotation, the oil film forming effect at low speed rotation hardly appears. Therefore, at the time of low speed rotation, the oil cannot form an oil film on the seal surface (the portion of the sliding surface 21 that actually slides relative to the annular groove), and cannot contribute to the reduction of torque and wear. .. This is because the apex of the protrusion 23 is inside the sliding surface 21 of the seal ring, and the oil that has entered the recess 22 (lubrication groove) flows over the protrusion 23 and flows to the adjacent recess 22 during low speed rotation. Think of it as a reason.

Further, the seal ring of Patent Document 2 easily introduces oil to the sliding surface 32, has excellent oil film forming properties on the sliding surface 32 from low speed rotation to high speed rotation, and has low torque. However, on the other hand, the area of the recess 34 in the sliding surface 32 cannot be made large, and the reduction of the sliding area is limited.

The present invention has been made to cope with such a problem, and provides a seal ring having a good balance between a low oil leak property, which is the original purpose of the seal ring, and a low torque property for improving fuel efficiency. The purpose is to

The seal ring of the present invention is mounted in an annular groove provided in one member of a housing having a shaft hole and a rotary shaft inserted into the shaft hole, is in contact with the surface of the other member, and A seal ring that slidably contacts a side wall surface on the non-sealing fluid side to seal an annular gap between these members, the seal ring being a ring side surface that is at least a sliding surface with the side wall surface. A concave portion that is a non-contact portion with the side wall surface is provided at a part of the inner diameter side end portion of the concave portion, and the concave portion includes a pair of V-shaped planes along the ring circumferential direction and the pair of flat surfaces. And an inclined plane which is connected to the plane and is inclined along the radial direction of the ring.

The recess is in communication with the inner peripheral surface of the ring, and the inclined flat surface is connected to the inner peripheral surface of the ring through the pair of flat surfaces connected to each other.

The inclination angle of the inclined plane is in the range of 30 to 60 degrees with respect to the plane perpendicular to the axial direction of the seal ring.

The recess is characterized in that the opening size on the outer diameter side is larger than the opening size on the inner diameter side.

The depth of the recess from the sliding surface has a deepest part other than the end part of the recess in the ring circumferential direction, and becomes shallower from the deepest part to both ends in the ring circumferential direction, and from the deepest part to the ring. It is characterized in that it becomes shallower toward the outside in the radial direction.

In the concave portion, the gradient of the boundary portion between the end portion of the concave portion in the ring circumferential direction and the sliding surface with respect to the sliding surface is larger than the gradient with respect to the sliding surface of the portion other than the boundary portion. It is characterized by

In the recess, the gradient of the boundary between the ring radial end of the inclined plane and the sliding surface with respect to the sliding surface is larger than the gradient with respect to the sliding surface of the portion other than the boundary. It is characterized by being

Further, a plurality of the recesses are provided so as to be spaced apart from each other in the ring circumferential direction, and a ring side surface between adjacent recesses constitutes a part of the sliding surface.

The seal ring of the present invention is mounted in an annular groove provided in one member of a housing having a shaft hole and a rotary shaft inserted into the shaft hole, is in contact with the surface of the other member, and is not in contact with the annular groove. It is slidably in contact with the side wall surface on the sealed fluid side to seal the annular gap between these members, and at least a part of the inner diameter side end of the ring side surface that becomes the sliding surface with the side wall surface. , A concave portion which is a non-contact portion with the side wall surface is provided, and the concave portion is connected to the pair of flat surfaces having a V-shape along the ring circumferential direction and the pair of flat surfaces and extends in the radial direction of the ring. Since the recess has a three-way tapered shape, the working oil, which is a sealing fluid, is slid on the ring circumferential direction side and the ring radial direction sliding surface via the recess. It is easy to leak to moderately. Therefore, the seal ring has a low oil leak property and a low torque property in good balance.

The concave portion communicates with the inner peripheral surface of the ring, and the inclined flat surface is connected to the inner peripheral surface of the ring through a pair of flat surfaces that are connected to each other. Since it easily flows smoothly and easily flows out to the sliding surface on the ring circumferential direction side, it is possible to secure low oil leakage while improving low torque.

The inclination angle of the inclined plane is in the range of 30 to 60 degrees with respect to the plane perpendicular to the axial direction of the seal ring, which is a relatively steep slope, so that the sliding surface on the outer diameter side of the recess slides. The area can be secured, and the low oil leak property can be suitably secured.

The hydraulic oil that has flowed into the recess flows out of the recess into the sliding surface due to relative rotation with the rotating shaft of the seal ring. At this time, by making the opening size on the outer diameter side larger than the opening size on the inner diameter side of the recess, it becomes possible to flow more hydraulic oil, etc., to the sliding surface, and a sufficient low torque performance is achieved. To do.

The depth from the sliding surface of the recess is the deepest part other than the end in the ring circumferential direction of the recess, and becomes shallower from the deepest part to both ends in the ring circumferential direction, and the ring radial direction is from the inside to the outside. Since it becomes shallower toward the bottom, the working oil or the like, which is a sealing fluid, easily flows out to the sliding surface between the adjacent concave portions and the sliding surface on the outer diameter side of the concave portions, and the torque is sufficiently low.

In the recess, the slope of the boundary between the ring circumferential end of the recess and the sliding surface with respect to the sliding surface is larger than the slope of the part other than the boundary with respect to the sliding surface. Even if the wear occurs, the reduction of the opening area of the recess is small and the torque does not change.

In the concave portion, the slope of the boundary between the end of the inclined plane in the radial direction of the ring and the sliding surface with respect to the sliding surface is larger than the slope with respect to the sliding surface of the portion other than the boundary. Even if the surface is worn, the decrease in the opening area of the recess is small and the torque does not change.

It is a perspective view etc. which show an example of the seal ring of this invention. It is a top view of the seal ring of FIG. It is sectional drawing which shows the state which assembled the seal ring of FIG. 1 in the annular groove. FIG. 3 is an enlarged view of part A in FIG. It is the figure which looked at the A section in FIG. 2 from the ring inner diameter side. It is an enlarged view of the D section in FIG. It is sectional drawing which shows an example of a boundary part. It is a figure which shows an example of the conventional seal ring. It is a figure which shows the other example of the conventional seal ring.

An example of the seal ring of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1A shows an overall perspective view of the seal ring, FIG. 1B shows a partially enlarged view of the abutment, and FIG. 2 shows a front view of the seal ring. As shown in FIGS. 1 and 2, the seal ring 1 is a ring-shaped body having a single mating port 4 and having a substantially rectangular cross section. A plurality of recesses 3 are provided at the inner diameter side ends of both side surfaces 2 of the ring along the ring circumferential direction, and the recesses 3 communicate with the ring inner peripheral surface 1b. The recess 3 has a three-direction taper shape composed of three inclined planes, as will be described later. The corners between the ring inner peripheral surface 1b and both side surfaces 2 (including the recess 3) of the ring may be provided with a linear or curved chamfer, and when the seal ring is manufactured by injection molding, You may provide the step part which becomes a part projected from a metal mold|die to a part.

FIG. 3 is a sectional view showing a state in which the seal ring of FIG. 1 is incorporated in an annular groove of a hydraulic system. The seal ring in FIG. 3 is shown in a state cut along the line B-B′ in FIG. As shown in FIG. 3, the seal ring 1 is mounted in an annular groove 6a provided in the rotary shaft 6 which is inserted into the shaft hole 5a of the housing 5. The arrow in the figure is the direction in which the pressure from the hydraulic oil is applied, and the right side in the figure is the non-sealing fluid side. The seal ring 1 is slidably in contact with the side wall surface 6b of the annular groove 6a on the non-sealing fluid side on the ring side surface 2 on the right side of the drawing. The outer peripheral surface 1a is in contact with the inner peripheral surface of the shaft hole 5a. This seal structure seals the annular gap between the rotary shaft 6 and the shaft hole 5a. It should be noted that the same can be applied to a configuration in which the annular groove is provided on the housing side instead of the rotating shaft side. Further, the type of hydraulic oil is appropriately used according to the application. In the present invention, it is mainly assumed that the oil temperature is about 30 to 150° C., the oil pressure is about 0.5 to 3.0 MPa, and the rotation speed of the rotating shaft is about 1000 to 7000 rpm.

The seal ring 1 is a cut type ring having a single mating port 4 (see FIG. 1), and is expanded in diameter by elastic deformation and mounted in the annular groove 6a. Since the seal ring 1 has the mating port 4, the seal ring 1 is expanded in diameter by the hydraulic pressure of the hydraulic oil during use, and the outer peripheral surface 1a comes into close contact with the inner peripheral surface of the shaft hole 5a. The shape of the mating port 4 may be a straight cut type, an angle cut type, or the like, but it is preferable to use the composite step cut type shown in FIG. 1B because it has excellent sealing properties.

In the seal ring 1 of the embodiment shown in FIGS. 1 to 3, one ring side surface 2 serves as a sliding surface with the side wall surface 6b of the annular groove 6a, and the ring side surface 2 (sliding surface) has an inner diameter side end portion. A three-direction tapered recessed portion 3 that is not in contact with the side wall surface is formed. By providing the concave portion 3, it becomes easy for the hydraulic fluid or the like, which is a sealing fluid, to appropriately flow out to the sliding surface through the concave portion. Specifically, the sliding surface X (see FIG. 1) between adjacent concave portions and the boundary portion between the concave portions have a continuous shape, and the sliding surface Y on the outer diameter side of the concave portion (see FIG. 1). Since the boundary between the concave portion and the concave portion has a continuous shape, the hydraulic oil or the like easily flows out to the sliding surface X or the sliding surface Y. When a hydraulic fluid, which is a sealing fluid, flows out to the sliding surfaces X and Y, an oil film can be formed on the sliding surfaces, and torque and wear can be reduced.

A portion of the ring side surface other than the concave portion on the inner diameter side, that is, a surface between adjacent concave portions on the inner diameter side (sliding surface X) is connected to the ring side surface on the outer diameter side in a plane, and the whole is non-inclined. It is a surface (a surface perpendicular to the axial direction of the seal ring). The recess 3 has a recessed shape when viewed from the inner diameter side surface (sliding surface X).

The three-way tapered recess will be described in detail with reference to FIG. FIG. 4A is an enlarged view of part A of the seal ring of FIG. 2, and FIG. 4B is a sectional view taken along line B-B′ of the seal ring C-C′ of FIG. 2. As shown in FIG. 4A, the concave portion 3 is connected to the pair of planes 3a and 3b inclined along the ring circumferential direction and the inclination inclined along the ring radial direction. And a plane 3c. The depth from the sliding surface of the concave portion 3 is the deepest except the end portion of the concave portion 3 in the ring circumferential direction, and in FIG. 4A, the deepest portion 3d is formed at the center position in the ring circumferential direction. The deepest part 3d is formed in a linear shape along the ring radial direction. The pair of flat surfaces 3a and 3b are formed such that the depths become shallower from the deepest portion 3d of the recess 3 toward both ends in the ring circumferential direction. The inclined flat surface 3c is formed so that the depth from the sliding surface becomes shallower from the outer diameter side edge (including the deepest portion 3d) of the pair of flat surfaces 3a and 3b toward the outer side in the ring radial direction. In the ring circumferential direction, the inclined flat surface 3c is formed so that the depth becomes shallower from the radially outer portion of the deepest portion 3d toward both ends in the ring circumferential direction.

Thus, the inclined plane 3c is an inclined plane that connects the pair of planes 3a and 3b and the sliding surface Y without any step. The shape of the boundary between the inclined planes 3c and 3a and the inclined planes 3c and 3b may be a curved shape in addition to a configuration in which the respective planes are simply connected.

As shown in FIG. 4A, the recess 3 has a substantially rectangular shape in a ring plan view when the seal ring is viewed from the axial direction. Among them, the pair of flat surfaces 3a and 3b have a substantially trapezoidal shape, and the length of each flat surface in the ring radial direction decreases from each boundary portion with the sliding surface toward the deepest portion 3d. The pair of flat surfaces 3a and 3b have their tapered ends connected to each other. On the other hand, in the plane view of the ring, the inclined plane 3c has a substantially triangular shape, and is located outside the pair of planes 3a and 3b in the ring radial direction. In this configuration, the inclined flat surface 3c is not directly connected to the ring inner peripheral surface 1b, but is connected to the ring inner peripheral surface 1b via the pair of flat surfaces 3a and 3b. It becomes easier to flow along the circumferential direction and more easily flows to the sliding surface X side. As a result, the outflow of hydraulic oil to the sliding surface Y is relatively small, and the low oil leak property can be improved. The areas of the pair of flat surfaces 3a and 3b are preferably substantially the same. In this case, assuming that each area of the pair of flat surfaces 3a and 3b is 1, the area ratio of the inclined flat surface 3c is preferably 1/4 to 1/2, and more preferably 1/3 to 1/2. preferable.

Further, as shown in FIG. 4A, in the concave portion 3, the length in the ring radial direction is constant, that is, the length of the sliding surface Y on the outer diameter side of the concave portion 3 in the ring radial direction is constant. It is preferable. This makes it easy to set the length of the sliding surface in the ring radial direction for ensuring the oil sealability.

Further, as shown in FIG. 4A, the opening size on the outer diameter side of the recess 3 is designed to be larger than the opening size on the inner diameter side. That is, in the ring side surface 2, the planar shape of the recess 3 which is a non-contact surface with the side wall surface of the annular groove is formed such that the non-contact area is larger on the outer diameter side than on the inner diameter side. By designing the recesses in this way, when the hydraulic oil that has flowed into the recesses flows out from the recesses due to the relative rotation with the rotating shaft of the seal ring, the opening size on the inner diameter side of the recesses is the opening size on the outer diameter side. Since it is smaller than the dimension, a larger amount of hydraulic oil or the like will flow out to the sliding surface as compared with the case where the opening dimension on the inner diameter side and the opening dimension on the outer diameter side of the recess are the same. This is because it is possible to suppress the amount of hydraulic oil or the like flowing out from the inside of the recess coming out to the inner diameter side of the seal ring when hitting the circumferential end of the recess.

FIG. 4B is a cross-sectional view taken along the line BB of the C-C′ region in the seal ring of FIG. 2, and is a view taken along the deepest portion 3d. As shown in FIG. 4B, the depth from the sliding surface in the deepest portion 3d is constant in the ring radial direction, and the depth from the sliding surface in the inclined plane 3c is the sliding surface in the ring radial direction. The closer to the area, the shallower it becomes. The inclination angle α of the inclined plane 3c is preferably in the range of 30 to 60 degrees with respect to the surface (ring side surface in FIG. 4B) perpendicular to the axial direction of the seal ring. More preferably, the inclination angle α is 30 degrees to 45 degrees. If the inclination angle α is less than 30 degrees, it becomes difficult to secure the length of the sliding surface Y in the ring radial direction, and the oil leak may increase. Further, if the inclination angle α exceeds 60 degrees, the hydraulic oil or the like is suppressed from flowing out, and sufficient torque reduction may not be obtained.

Further, the inclination angle α is preferably larger than the angle (inclination angle β (see FIG. 5)) formed between the plane perpendicular to the axial direction of the seal ring and the plane 3a or the plane 3b. In this case, the inclination angle of the inclined plane 3c is steeper than the inclination angle of the planes 3a and 3b with respect to the plane perpendicular to the axial direction of the seal ring. By providing the gradient difference in this way, the working oil or the like is more likely to flow out to the sliding surface X than to the sliding surface Y, and the oil sealability can be improved. The inclination angle β is preferably 1 to 30 degrees, more preferably 5 to 20 degrees. In FIG. 5, the inclination angle β is shown as an angle formed by the imaginary plane L parallel to the axial direction with respect to the ring side surface 2 which is a plane perpendicular to the axial direction of the seal ring and the plane 3a or the plane 3b. .. The distance between the ring side surface 2 and the virtual surface L is the depth from the sliding surface in the deepest part 3d.

The length T ₂ in the ring radial direction of the recess 3 (including the pair of flat surfaces 3a and 3b and the inclined flat surface 3c) shown in FIG. 4B is preferably 10 to 60% of the total ring thickness T ₃ , It is more preferably from 20 to 50%, further preferably from 30 to 40%. The length T ₁ of the deepest portion 3d in the ring radial direction is preferably 20 to 80% of the length T ₂ of the recess in the ring radial direction, more preferably 30 to 70%, and more preferably 40 to. It is more preferably 60%.

The recess 3 may be formed at least on the side surface of the ring that is the sliding surface, but since it does not depend on the assembly direction and has excellent weight balance, it can be formed on both side surfaces of the ring as shown in FIG. 4B. It is preferable to form them symmetrically.

Further, as shown in FIG. 2, it is preferable that a plurality of recesses 3 are provided at intervals in the ring circumferential direction. The ring side surface 2 between the adjacent recesses constitutes a part of the sliding surface (sliding surface X). As described above, during use, an oil film can be formed on the sliding surface between the adjacent recesses, and torque and wear can be reduced. The length of each recess in the ring circumferential direction is preferably about 3 to 20% of the entire circumference of the ring, depending on the number. Further, since the sliding characteristics are stable, it is preferable that all the recesses have the same size and that a plurality (14 in FIG. 1) be provided at substantially equal intervals.

FIG. 5 is a view of a portion A of the seal ring of FIG. 2 viewed from the ring inner diameter side. As shown in FIG. 5, the pair of flat surfaces 3a and 3b are inclined from the sliding surface (ring side surface 2) toward the center in the width direction along the ring circumferential direction, and V along the ring circumferential direction. Form a letter. One of the ring side surfaces 2 is a sliding surface with the annular groove. As shown in FIG. 5, the depth from the sliding surface in the pair of flat surfaces 3a and 3b becomes shallower in the region closer to the sliding surface in the ring circumferential direction, and is constant in the ring radial direction.

In the example shown in FIGS. 1 to 5, the position of the deepest portion 3d in the recess 3 is the center position of the recess 3 in the ring circumferential direction, but the position is not particularly limited to this. Further, the shape of the deepest part 3d of the recess 3 may be a V-shape in which the planes 3a and 3b are simply connected, or a curved shape or a horizontal shape.

The depth of the deepest portion 3d of the recess 3 from the sliding surface is preferably 45% or less of the total ring width, and more preferably 30% or less. The "depth" here is the sum of the depths of the recesses on the side surfaces when the recesses are formed on both side surfaces of the ring. If it exceeds 45% of the total width of the ring, the ring may be greatly deformed during use.

The boundary between the ring circumferential end of the recess and the sliding surface will be described with reference to FIGS. 6 and 7. 6 is an enlarged view of part D in FIG. 5, and FIG. 7 is an enlarged cross-sectional view showing an example of the boundary portion. As shown in FIG. 7A, the boundary portion 3f between the end portion of the recess 3 in the ring circumferential direction and the sliding surface (ring side surface 2) is formed to have a steep slope with respect to the sliding surface. preferable. That is, in the concave portion 3, it is preferable that the gradient of the boundary portion 3f with respect to the sliding surface is larger than the gradient of the portion other than the boundary portion 3f with respect to the sliding surface. With this configuration, as compared with the case where no steep slope is formed (FIG. 7B), even if the sliding surface is worn to the same extent, the decrease in the opening area of the recess is small and the torque does not change. This steep slope can be formed in a convex R shape on the center side in the width direction of the ring, as shown in FIG. 6, for example. By forming the steep slope portion of the boundary portion 3f in an R shape, the hydraulic fluid, which is a sealing fluid, is more likely to flow out to the sliding surface, and the torque is further reduced.

6 and 7, the boundary portion 3f between the end portion of the recess 3 in the ring circumferential direction and the sliding surface (ring side surface 2) has been described, but the end portion of the inclined plane 3c in the ring radial direction and the sliding surface ( It is preferable that the boundary portion 3e (see FIG. 4B) with the ring side surface 2) also has the same configuration. That is, in the concave portion 3, it is preferable that the gradient of the boundary portion 3e with respect to the sliding surface is larger than the gradient of the portion other than the boundary portion 3e with respect to the sliding surface.

The material of the seal ring of the present invention is not particularly limited, but it may be a molded product of synthetic resin in consideration of forming the above-mentioned concave portion on the side surface, expanding the diameter by elastic deformation and mounting it in the groove. preferable. Examples of synthetic resins that can be used include thermosetting polyimide resins, thermoplastic polyimide resins, polyetherketoneetherketoneketone resins, polyetherketone resins, polyetheretherketone (hereinafter referred to as PEEK) resins, wholly aromatic polyesters. Resin, fluororesin such as polytetrafluoroethylene (hereinafter referred to as PTFE) resin, polyphenylene sulfide (hereinafter referred to as PPS) resin, polyamide imide resin, polyamide resin and the like can be mentioned. These resins may be used alone or as a polymer alloy in which two or more kinds are mixed.

The synthetic resin is used for the seal ring because it is easy and inexpensive to manufacture the seal ring that has the above-mentioned recesses and compound step cut joints, and the rotation torque is stable compared to when it is machined. It is preferable to use an injection-molded body obtained by molding. Therefore, it is preferable to use a thermoplastic resin that can be injection-molded as the synthetic resin. Among them, it is particularly preferable to use PEEK resin or PPS resin because they are excellent in friction and wear characteristics, bending elastic modulus, heat resistance, slidability and the like. These resins have a high elastic modulus, do not break even when expanded in diameter when incorporated in a groove, can be used even when the oil temperature of the working oil to be sealed is high, and do not cause solvent cracks.

Further, if necessary, in the above synthetic resin, fibrous reinforcing material such as carbon fiber, glass fiber, aramid fiber, spherical filler such as spherical silica or spherical carbon, scaly reinforcing material such as mica or talc, potassium titanate whisker. Microfiber reinforcements such as Further, PTFE resin, graphite, solid lubricants such as molybdenum disulfide, sliding reinforcing materials such as calcium phosphate and calcium sulfate, carbon black and the like can be blended. These may be blended alone or in combination. Particularly, PEEK resin or PPS resin containing carbon fiber which is a fibrous reinforcing material and PTFE resin which is a solid lubricant is preferable because the characteristics required for the seal ring of the present invention can be easily obtained. By blending carbon fiber, mechanical strength such as flexural modulus can be improved, and by blending PTFE resin, sliding characteristics can be improved.

When it is made of synthetic resin, the above raw materials are melt-kneaded to form a pellet for molding, which is molded into a predetermined shape by a known injection molding method or the like. In the case of manufacturing by injection molding, the gate position is not particularly limited, but it is preferable to provide it on the inner peripheral surface of the ring from the viewpoint of ensuring the sealing property and the need for post-processing. Further, it is preferable that the gate position is provided at the facing portion of the inner peripheral surface of the ring from the viewpoint of flow balance in injection molding.

The seal ring of the present invention has a good balance between the low oil leak property, which is the original purpose of the seal ring, and the low torque property, so that it can be used as a seal ring that requires these characteristics between the rotary shaft and the housing. .. In particular, it can be suitably used for hydraulic equipment such as AT and CVT in automobiles for improving fuel efficiency.

1 Seal Ring 2 Ring Side 3 Recess 3a Plane 3b Plane 3c Inclined Plane 3d Deepest Part 3e Boundary 3f Boundary 4 Fitting 5 Housing 6 Rotating Shaft

Claims (8)

A housing having an axial hole and a side wall surface of the annular groove, which is attached to an annular groove provided in one member of a rotary shaft inserted into the axial hole, is in contact with the surface of the other member, and is on the non-sealing fluid side of the annular groove. A seal ring that slidably contacts with and seals the annular gap between these members,
In the seal ring, at least a part of the inner diameter side end portion of the ring side surface that is a sliding surface with the side wall surface is provided with a recess that is a non-contact portion with the side wall surface,
The seal ring is characterized in that the concave portion has a pair of V-shaped planes along the ring circumferential direction and an inclined plane connected to the pair of planes and inclined along the ring radial direction. The seal according to claim 1, wherein the recess is in communication with an inner peripheral surface of a ring, and the inclined flat surface is connected to the inner peripheral surface of the ring through the pair of flat surfaces connected to each other. ring. The seal ring according to claim 1 or 2, wherein an inclination angle of the inclined plane is in a range of 30 to 60 degrees with respect to a plane perpendicular to the axial direction of the seal ring. The seal ring according to any one of claims 1 to 3, wherein the recess has a larger opening size on the outer diameter side than an opening size on the inner diameter side. The depth of the recess from the sliding surface has a deepest part other than the end part of the recess in the ring circumferential direction, and becomes shallower from the deepest part to both ends in the ring circumferential direction, and from the deepest part to the ring. The seal ring according to any one of claims 1 to 4, which is shallower toward the outer side in the radial direction. In the concave portion, a gradient of a boundary portion between an end portion of the concave portion in the ring circumferential direction and the sliding surface with respect to the sliding surface is larger than a gradient of a portion other than the boundary portion with respect to the sliding surface. The seal ring according to any one of claims 1 to 5, wherein: In the concave portion, the gradient of the boundary portion between the end of the inclined plane in the ring radial direction and the sliding surface with respect to the sliding surface is larger than the gradient of the portion other than the boundary with respect to the sliding surface. The seal ring according to any one of claims 1 to 6, which is characterized by being provided. 8. A plurality of said recesses are provided spaced apart in the ring circumferential direction, and a ring side surface between adjacent recesses constitutes a part of said sliding surface. The seal ring according to item 1.

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