JP2022058162A - Seal ring - Google Patents

Abstract

To provide a seal ring which is made of a resin, eliminates a need to form a conventional resin sump which is removed after molding, and achieves good flatness and sealability.SOLUTION: A seal ring 1 seals an annular gap between a housing and a shaft assembled to an interior of the housing and is made of a resin. The seal ring 1 includes at least an annular seal ring body 1A having an abutment part 15 and tabs 10 which are formed at the inner peripheral surface side of the seal ring body 1A so as to protrude to the radial inner side. The tabs 10 are formed near the abutment part 15.SELECTED DRAWING: Figure 3

Description

The present invention relates to a seal ring, for example, a seal ring for sealing a lubricating oil interposed in a gap between a shaft and a housing used in an automatic transmission (AT) of an automobile.

For example, a plurality of seal rings are used in an automatic transmission (AT) for an automobile. The annular seal ring 100 as shown in FIGS. 8 and 9 is assembled between the shaft 300 and the housing 200 that move relative to each other in the hydraulic circuit of the transmission, and serves to seal the lubricating oil while sliding. Fulfill.

As shown in FIG. 8, the seal ring 100 may be provided with tabs 101 protruding inward in the radial direction at a plurality of locations on the inner peripheral surface 100a side of the seal ring 100.
This tab 101 is for preventing the center of the seal ring 100 from being significantly deviated from the center of the shaft by abutting the tip of the shaft 300 on the bottom surface of the annular groove 301 when the shaft 300 is assembled inside the housing 200. Is.

Further, as shown in FIG. 8, the seal ring 100 is formed with a joint portion 102. The abutment portion 102 is a part of the seal ring 100 cut off, and when the abutment portion 102 is attached to the shaft 300, the abutment portion 102 is expanded and attached.

The seal ring includes polyamide (PA), fluororesin (polytetrafluoroethylene (tetrafluoro) (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / ethylene copolymer). (ETFE), etc.) and its alloy materials, liquid crystal polymers (LCP), polyimide (PI), polyetherketone (PEK), polyaryletherketone (PAEK), polyetherketone etherketoneketone (PEKEKK), polyetheretherether A ring-shaped injection-molded material containing reinforcing materials (called filler fibers) such as carbon fibers in super-engineering plastics such as ketone (PEEK) and polyphenylene sulfide (PPS), and polybenzoimidazole (PBI). Is often used.

Further, regarding injection molding of the seal ring, as shown in FIG. 10, in Patent Document 1, the gate 153 is arranged at a position shifted from the facing portion 152 on the seal ring 150 of the joint portion 151, and then the gate 153 and the gate 153 are arranged. It has been proposed to provide the resin reservoir 154 on the side having a shorter distance from the abutment portion 151 (flow length T1 side).

By adopting this configuration, in the method for manufacturing the seal ring 150 shown in Patent Document 1, the one having a longer distance between the gate 153 and the abutment portion 151 (flow length T2 side) and the gate 153 are used. It is said that the resin filling amount can be the same as that of the one having a shorter distance from the abutment portion 151 (flow length T1 side), the resin can be filled without excess or deficiency, and the occurrence of defects such as burrs can be prevented. There is.

Japanese Unexamined Patent Publication No. 2004-205003

By the way, even when the gate is arranged on the opposite portion of the abutment portion, when the resin containing the filler fiber is actually injection-molded to form the seal ring, the thickness in the vicinity of the abutment portion becomes the thickness of the seal ring main body. There was a problem that it became thicker than other parts.
Specifically, this event will be described with reference to FIGS. 11 and 12. FIG. 11A is a cross-sectional view perpendicular to the axis of the seal ring main body at a location other than the vicinity of the abutment portion of the seal ring main body. 11 (b) is a partially enlarged view of FIG. 11 (a). FIG. 12A is a cross-sectional view taken along the axis of the seal ring main body in the vicinity of the abutment portion of the seal ring main body. 12 (b) is a partially enlarged view of FIG. 12 (a).

As shown in FIG. 11B, the filler fiber F is visually recognized as elongated in a portion other than the vicinity of the abutment portion of the seal ring main body, and the axis of the filler fiber F is perpendicular to the axis of the seal ring main body. (The axis of the filler fiber F is oriented parallel to the flow direction of the molten resin).
On the other hand, in FIG. 12 (b), the state in which the axis of the filler fiber F is oriented in the direction perpendicular to the axis of the seal ring main body as shown in FIG. 11 (b) cannot be visually recognized.
That is, it can be seen that the axis of the filler fiber in the vicinity of the abutment portion of the seal ring main body is oriented in the direction perpendicular to the flow direction of the molten resin.

The above event is caused by the fact that the resin collides with the abutment end of the mold corresponding to the abutment end of the seal ring main body in the mold, and the orientation of the filler fibers is disturbed. Since the filler fibers are oriented in the direction perpendicular to the flow direction of the molten resin in the vicinity of the abutment portion of the seal ring, the curing shrinkage rate of that portion is the curing shrinkage rate of other portions (locations other than the vicinity of the abutment portion). Become smaller. As a result, the thickness in the vicinity of the abutment portion becomes thicker than that in the other portions.

As described above, when the thickness in the vicinity of the abutment portion is thicker than that of other parts of the seal ring main body, the flatness of the seal ring main body is further deteriorated, and the sealing performance of the seal ring is deteriorated.
In addition, in the case where a gate is arranged at the portion of the mold corresponding to the opposite portion of the abutment portion of the seal ring main body, and a resin containing a filler fiber is injection-molded from this gate to form the seal ring, as described above. When a large resin pool is formed, the resin pool must be removed accurately after injection molding, which requires more labor and materials, and has a problem of high cost.

The present invention has been made to solve the above technical problems, and it is not necessary to form a resin pool to be removed after injection molding as in a conventional case in a resin seal ring containing filler fibers. It is an object of the present invention to provide a sealing ring having good flatness and sealing property.

In order to solve the above problems, the seal ring according to the present invention is a seal ring that seals an annular gap between the housing and the shaft assembled inside the housing, and a resin pool is not formed during injection molding. In a resin seal ring containing filler fibers, an annular seal ring body having an abutment portion and a plurality of tabs formed so as to project radially inward on the inner peripheral surface of the seal ring body. , The tab is characterized in that it is formed at least in the vicinity of the abutment portion.

As described above, the seal ring according to the present invention includes a plurality of tabs formed so as to project radially inward on the inner peripheral surface of the seal ring main body, and the tabs are formed at least in the vicinity of the abutment portion. During injection molding of the seal ring, the molten resin flows into the tab forming portion of the mold, and the internal pressure of the mold in the region of the mold corresponding to the vicinity of the abutment portion of the seal ring main body is reduced.
As described above, the curing shrinkage rate tends to be smaller in the vicinity of the abutment portion where the filler orientation is disturbed than in the vicinity of the abutment portion other than the vicinity of the abutment portion.
Further, the internal pressure of the mold is reduced in the vicinity of the abutment portion, and the reduction of the internal pressure of the mold tends to increase the curing shrinkage rate. Therefore, in the vicinity of the abutment portion, the decrease in the curing shrinkage rate due to the disorder of the filler orientation and the increase in the curing shrinkage rate due to the reduction in the internal pressure of the mold are offset.
As a result, the curing shrinkage rate in the vicinity of the abutment portion and in other parts of the seal ring body becomes substantially the same, and the thickness in the vicinity of the abutment portion and the thickness in other parts of the seal ring main body become substantially equal. The sealing property can be improved.
Further, since the resin pool is not formed as in the conventional case, it is not necessary to remove the resin pool after injection molding of the seal ring, and the man-hours and materials can be reduced.

Further, it is desirable that the length dimension from the end of the abutment portion to the end of the tab closest to the end of the abutment portion is 0.5 mm or more and 2.5 mm or less.
If the length from the end of the abutment to the end of the tab closest to the end of the abutment exceeds 2.5 mm, the length will be large and the molten resin will be used as the tab forming part of the mold. The effect of reducing the internal pressure of the mold due to the inflow is small.
On the other hand, even if the length from the end of the abutment to the end of the tab closest to the end of the abutment is less than 0.5 mm, the internal pressure of the mold due to the molten resin flowing into the tab forming portion of the mold. Although the effect of reduction can be obtained, if the length dimension is less than 0.5 mm, the shape of the abutment portion becomes complicated and it becomes difficult to manufacture the mold, which is not preferable.

The length dimension of the filler fiber is preferably 1000 μm or less.
If the length of the filler fiber exceeds 1000 μm, shrinkage anisotropy during injection molding becomes strong, which is not preferable. Further, it is desirable that the average length of the filler fibers is about 200 μm.

Further, the cross-sectional area parallel to the axis of the tab and the seal ring main body at the position of the tab formed in the vicinity of the abutment portion is parallel to the axis of the seal ring main body at the positions on both the left and right sides of the tab. It is desirable that it is larger than the cross-sectional area.
As described above, since the cross-sectional area parallel to the axis of the tab and the seal ring main body combined is larger than the cross-sectional area parallel to the axis of the seal ring main body at the positions on both the left and right sides of the tab, the vicinity of the abutment portion. It is possible to reduce the internal pressure of the mold in the region of the mold corresponding to the above.

Further, in the abutment portion, one end portion and the other end portion of the seal ring main body face each other, and the cross-sectional area parallel to the axis is formed on the axis line of the seal ring main body at the one end portion and the other end portion. It is desirable to have engaging protrusions or recesses that are smaller than the parallel cross-sectional area and are engageable with each other.

In this way, even if an engaging convex portion or an engaging concave portion having a cross-sectional area parallel to the axis line smaller than the cross-sectional area parallel to the axis line of the seal ring body is formed at one end and the other end of the abutment portion, During injection molding of the seal ring, the molten resin flows into the tab forming portion of the mold, and the internal pressure of the mold in the region of the mold corresponding to the vicinity of the abutment portion of the seal ring main body is reduced.
Therefore, as described above, the curing shrinkage rate tends to be smaller in the vicinity of the abutment portion where the filler orientation is disturbed with respect to the portion other than the vicinity of the abutment portion. The curing shrinkage tendency tends to increase due to the reduction of the mold internal pressure.
As a result, in the vicinity of the abutment portion, the decrease in the curing shrinkage rate due to the disorder of the filler orientation and the increase in the curing shrinkage rate due to the reduction in the internal pressure of the mold are offset, and the thickness in the vicinity of the abutment portion and the thickness of other parts of the seal ring body are increased. It becomes substantially uniform, and the flatness and sealing property of the seal ring can be improved.

Further, it is desirable that the inclination angle of the side surface of the tab with respect to the circumferential direction of the seal ring main body is set within a range of 100 ° or more and 150 ° or less.
If the inclination angle of the side surface of the tab is less than 100 °, the orientation of the filler fibers in the tab is likely to be disturbed, which is not preferable. In addition, when the inclination angle of the side surface of the tab exceeds 150 °, the circumferential length of the tab becomes long, and the curing shrinkage rate also increases in places other than the vicinity of the abutment portion, which leads to deterioration of flatness. Not preferred.

Further, it is desirable that the radial thickness dimension of the tab is formed smaller than the radial thickness dimension of the seal ring main body.
When the radial thickness dimension of the seal ring main body is formed smaller than the radial thickness dimension of the tab, the mechanical strength of the seal ring main body becomes small, which is not preferable.

Further, the seal ring main body is formed so as to be mountable on an annular groove formed in a shaft inserted into the housing, and at the time of mounting, the tip of the plurality of tabs is the groove bottom surface of the annular groove. It is desirable that it is formed so as to be able to come into contact with the.

According to the present invention, in a resin-made seal ring containing filler fibers, it is not necessary to form a resin pool to be removed after injection molding as in the conventional case, and it is possible to obtain a seal ring having good flatness and sealing property. can.

FIG. 1 is a perspective view of a seal ring according to an embodiment of the present invention. FIG. 2 is a perspective view of the seal ring of FIG. 1 as viewed from another direction. 3A is a plan view of the seal ring of FIGS. 1 and 2, and FIG. 3B is a side view of the seal ring as viewed from the outside. FIG. 4 is a cross-sectional view parallel to the axis of the seal ring main body in a state where the seal ring according to the embodiment of the present invention is mounted in the annular groove of the shaft. 5 (a) is an enlarged perspective view of the abutment portion and tabs in the vicinity thereof, and FIG. 5 (b) is a sectional view taken along the line II of FIG. 5 (a). FIG. 6A is an enlarged plan view of the abutment portion and tabs in the vicinity thereof, and FIG. 6B is a side view of the abutment portion as viewed from the outside of the seal ring. 7A and 7B show other forms of the abutment portion, FIG. 7A is an enlarged plan view of the abutment portion and a tab in the vicinity thereof, and FIG. 7B shows the abutment portion outside the seal ring. It is a side view seen from the entwined. FIG. 8 is a perspective view of a conventional seal ring. FIG. 9 is a cross-sectional view taken along the axis of the seal ring main body in a state where the shaft with the conventional seal ring is attached to the housing. FIG. 10 is a plan view of a conventional seal ring. 11A and 11B are conventional seal rings, in which FIG. 11A is a cross-sectional view perpendicular to the axis of the seal ring body at a location other than the vicinity of the abutment portion of the seal ring body, and FIG. 11B is one of (a). It is a part enlarged view. 12A and 12B are conventional seal rings, in which FIG. 12A is a cross-sectional view perpendicular to the axis of the seal ring body in the vicinity of the abutment portion of the seal ring body, and FIG. 12B is a partially enlarged view of FIG. be.

Hereinafter, embodiments of the seal ring according to the present invention will be described with reference to the drawings. The seal ring in the present embodiment is, for example, assembled between a shaft and a housing that move relative to each other in a hydraulic circuit of an automatic transmission of an automobile, and plays a role of sealing lubricating oil while sliding.
FIG. 1 is a perspective view of a seal ring according to an embodiment of the present invention, and FIG. 2 is a perspective view of the seal ring of FIG. 1 as viewed from another direction. 3A is a plan view of the seal ring of FIGS. 1 and 2, and FIG. 3B is a side view of the seal ring as viewed from the outside. Further, FIG. 4 is a cross-sectional view parallel to the axis of the seal ring main body in a state where the seal ring according to the embodiment of the present invention is mounted in the annular groove of the shaft.
The axis of the seal ring main body passes through the center C (center of the ring) of the annular seal ring in a state where the seal ring according to the embodiment of the present invention is mounted in the annular groove of the shaft, and the seal ring is formed. A line extending in the direction perpendicular to the plane including the first sealing surface.

The illustrated seal ring 1 is a polymer (PA), a fluororesin (polytetrafluoroethylene (tetrafluoro) (PTFE)), and a tetrafluoroethylene / perfluoroalkyl vinyl ether that seals the gap between the housing and the shaft. Polymers (PFA), tetrafluoroethylene / ethylene copolymers (ETFE), etc.) and their alloy materials, liquid crystal polymers (LCP), polyimide (PI), polyetherketone (PEK), polyetheretherketone (PAEK) , Polyetherketone Etherketone Ketone (PEKEKK), Polyetheretherketone (PEEK), Super engineering plastics typified by polyphenylene sulfide (PPS), Polybenzoimidazole (PBI), etc. It includes an annular seal ring main body 1A formed of the blended material, and a plurality of tabs 10 formed on the inner peripheral surface of the seal ring main body 1A. The cross section of the seal ring main body 1A parallel to the axis of the seal ring main body 1A at the portion where the tab 10 is not formed is formed in a rectangular shape.
The seal ring 1 is a resin seal ring in which the resin pool shown in Patent Document 1 is not formed. Further, as described above, the seal ring 1 has high wear resistance because the resin contains filler fibers.

More specifically, as shown in FIG. 4, the oil seal side (seal surface side) of the seal ring main body 1A is provided with a first seal surface 2. The first sealing surface 2 slides into contact with the side wall surface (side surface of the annular groove on the oil seal side) 21a of the annular groove 21 of the shaft 20 to seal the side wall surface 21a.
Further, the outer peripheral surface of the seal ring main body 1A is the second seal surface 5. The second sealing surface 5 contacts and seals the inner peripheral surface 31 of the housing 30.

As described above, a plurality of (six in the figure) tabs 10 are provided on the inner peripheral surface 7 of the seal ring 1 shown in FIGS. 1 to 3 at predetermined intervals.
Each tab 10 projects radially inward from the inner peripheral surface 7 as shown in FIG. 3, and when the seal ring 1 is attached to the annular groove 21 of the shaft 20 as shown in FIG. 4, the seal ring main body 1A and the shaft When misalignment occurs in 20, the tip portion 10a of the tab 10 comes into contact with the groove bottom surface 21b of the annular groove 21.
As described above, as one of the functions, the tab 10 has a function of preventing the center C of the seal ring main body 1A from being significantly deviated from the center of the shaft 20 when the shaft 20 is assembled inside the housing 30. There is.

Further, as shown in FIGS. 1 to 3, a joint portion 15 (separation portion) is formed at one position in the circumferential direction of the seal ring 1, and when the seal ring 1 is attached to the shaft 20, the joint portion 15 is used. By expanding the seal ring 1 in the direction of separation, it can be easily attached to the annular groove 21 of the shaft 20.
The tabs 10 are provided at least in the vicinity of both ends of the seal ring main body 1A separated by the joint portion 15.

Specifically, the tab 10 is provided at least in the vicinity of the end portion of the abutment portion 15 of the seal ring main body 1A (a portion where the cross-sectional area changes in the abutment portion 15).
As a result, during injection molding of the seal ring 1, molten resin containing filler fibers flows into the tab forming portion of the mold, and the internal pressure of the mold in the region of the mold corresponding to the vicinity of the abutment portion of the seal ring main body 1A is reduced. Will be done.
Further, as described above, the curing shrinkage rate tends to be smaller in the vicinity of the abutment portion where the filler orientation is disturbed with respect to the portion other than the vicinity of the abutment portion. The internal pressure of the mold is reduced in the vicinity of the abutment portion, and the reduction of the internal pressure of the mold tends to increase the curing shrinkage rate.
Therefore, in the vicinity of the abutment portion, the decrease in the curing shrinkage rate due to the disorder of the filler orientation and the increase in the curing shrinkage rate due to the reduction in the internal pressure of the mold are offset.
As a result, the curing shrinkage rate in the vicinity of the abutment portion and in other parts of the seal ring body becomes substantially the same, and the thickness in the vicinity of the abutment portion and the thickness in other parts of the seal ring main body become substantially equal. The sealing property can be improved.

The length of the filler fiber contained in the resin forming the seal ring 1 is preferably 1000 μm or less. If the length of the filler fiber exceeds 1000 μm, shrinkage anisotropy during injection molding becomes strong, which is not preferable.
Further, it is desirable that the average length of the filler fibers is about 200 μm.
The filler fiber is not limited to the above length, and may be any shape and size that can exhibit the effect of wear resistance. Further, although carbon fiber is exemplified as the filler fiber, the present invention is not limited to carbon fiber, and may be, for example, glass fiber or CNF (cellulose nanofiber).

Next, the structure of the joint portion 15 and the tab 10 will be described in detail.
5 (a) is an enlarged perspective view of the abutment portion 15 and the tab 10 in the vicinity thereof, and FIG. 5 (b) is a cross-sectional view taken along the line II of FIG. 5 (a). Further, FIG. 6A is an enlarged plan view of the abutment portion 15 and the tab 10 in the vicinity thereof, and FIG. 6B is a side view of the abutment portion 15 as viewed from the outside of the seal ring main body 1A. ..

The joint portion 15, that is, the portion where one end and the other end of the seal ring body 1A face each other, has a cross-sectional area parallel to the axis smaller than the cross-sectional area parallel to the axis of the seal ring body 1A. It has an engaging protrusion or an engaging recess that can be engaged.
Specifically, on one end side of the seal ring main body 1A, an inner peripheral side wall 15a extending in a wall shape in the circumferential direction is formed on the inner peripheral surface of the seal ring main body 1A.
Further, on the radial outer side of the inner peripheral side wall 15a, a lower step portion 15b extending in the circumferential direction in a stepped shape is formed. By forming the lower portion 15b, an upper recess 15c is formed above the lower portion 15b.

On the other hand, on the other end side of the seal ring main body 1A, an inner peripheral side recess 15d formed so that the inner peripheral side wall 15a can be engaged is formed on the inner peripheral surface of the seal ring main body 1A.
Further, on the radial outer side of the inner peripheral side recess 15d, the upper portion 15e is formed so as to be engageable on the lower portion 15b and engages with the upper recess 15c.
By forming the upper portion 15e, a lower recess 15f is formed below the upper portion 15e, and the lower portion 15b is engaged with the lower recess 15f.
In this way, in the abutment portion 15, both ends of the seal ring main body 1A are formed in a stepped shape, and due to the structure of engaging with each other, the first seal surface 2 which is a sealing surface when the abutment portion 15 is closed. And the non-sealed surface 6 do not communicate with each other, and the second sealed surface 5 and the non-sealed surface 7 do not communicate with each other, so that the sealing performance is improved.

Further, as shown in FIG. 6A, as described above, the tab 10 is provided at least in the vicinity of the end portion of the abutment portion 15 of the seal ring main body 1A (the portion where the cross-sectional area changes in the abutment portion 15). Has been done. Preferably, the length dimension L1 from the end of the abutment portion 15 to the end of the tab 10 closest to the end of the abutment portion 15 is formed to be 0.5 mm or more and 2.5 mm or less.
The length dimension L1 from the end of the abutment portion 15 to the tab 10 closest to the abutment portion 15 means that both ends of the seal ring main body 1A are formed in a stepped shape, that is, the cross-sectional shape of the abutment portion 15 of the seal ring main body 1A has a cross-sectional shape. It is a length dimension from the changing position (the end of the abutment portion) to the tab 10 closest to it.

When the length from the end of the abutment to the end of the tab closest to the end of the abutment exceeds 2.5 mm, the length becomes large, so that the molten resin forms a tab for the mold. The effect of reducing the internal pressure of the mold by flowing into the part is small.
On the other hand, even if the length from the end of the abutment to the end of the tab closest to the end of the abutment is less than 0.5 mm, the internal pressure of the mold due to the molten resin flowing into the tab forming portion of the mold. Although the effect of reduction can be obtained, if the length dimension is less than 0.5 mm, the shape of the abutment portion becomes complicated and it becomes difficult to manufacture the mold, which is not preferable.

Further, the inclination angle of the side surface of the tab with respect to the circumferential direction of the seal ring main body is set within a range of 100 ° or more and 150 ° or less.
If the inclination angle of the side surface of the tab is less than 100 °, the orientation of the filler fibers in the tab is likely to be disturbed, which is not preferable. In addition, when the inclination angle of the side surface of the tab exceeds 150 °, the circumferential length of the tab becomes long, and the curing shrinkage rate also increases in places other than the vicinity of the abutment portion, which leads to deterioration of flatness. Not preferred.

Further, as shown in FIG. 6A, the radial thickness dimension L2 of the tab 10 is formed to be smaller than the radial thickness dimension L3 of the seal ring main body 1A.
When the radial thickness dimension L3 of the seal ring main body is formed smaller than the radial thickness dimension L2 of the tab, the radial thickness dimension of the seal surface 2 of the seal ring main body 1A is small. This is not preferable because the sealing performance is deteriorated.
Therefore, from the viewpoint of the sealing performance of the seal ring main body 1A, it is preferable that the radial thickness dimension L3 of the seal ring main body 1A is formed larger than the radial thickness dimension L2 of the tab 10.

Further, as shown in FIG. 5B, the cross-sectional area S1 parallel to the axis in which the tab 10 and the seal ring main body 1A are combined is a seal at the positions on both the left and right sides of the tab 10 (positions where the tabs are not formed). It is formed larger than the cross-sectional area S2 parallel to the axis of the ring body 10.
As a result, during the injection molding of the seal ring 1, the molten resin containing the filler fibers flows into the tab forming portion of the mold, and the internal pressure of the mold in the region of the mold corresponding to the vicinity of the abutment portion is reduced.

The seal ring 1 thus configured is obtained by injecting a molten resin containing filler fibers into a mold (not shown).
In the mold, the gate into which the resin flows is formed at the portion of the mold corresponding to the facing portion of the joint portion 15 of the seal ring 1. In the molded seal ring 1, as shown in FIG. 2, a gate mark 17 is formed on the inner peripheral surface 7 of the facing portion of the abutment portion 15 on the seal ring 1.

The molten resin injected by the injection nozzle (not shown) flows into the mold from the gate of the mold, is divided into left and right sides, and flows toward the forming portion of the abutment portion 15 by a predetermined mold internal pressure. It will be.

Further, the molten resin flowing from the gate to both the left and right sides also flows into the tab forming portion of the mold corresponding to the tab 10 as described above.
Since the tab forming portion is provided in the vicinity of the abutment forming portion of the mold corresponding to the abutment portion 15, the molten resin passing through the tab forming portion, that is, the gold of the molten resin in the vicinity of the abutment forming portion. The mold internal pressure is reduced by the tab forming portion.

As described above, the curing shrinkage rate tends to be smaller in the vicinity of the abutment portion where the filler orientation is disturbed than in the vicinity of the abutment portion other than the vicinity of the abutment portion.
Further, since the tab forming portion reduces the internal pressure of the molten resin in the vicinity of the abutment forming portion, the curing shrinkage tendency tends to increase due to the reduction of the internal pressure of the mold.
Therefore, in the vicinity of the abutment portion, the decrease in the curing shrinkage rate due to the disorder of the filler orientation and the increase in the curing shrinkage rate due to the reduction in the internal pressure of the mold are offset.
As a result, the thickness in the vicinity of the abutment portion and the thickness of other parts of the seal ring main body become substantially equal, and the flatness and sealability of the seal ring can be improved.
Further, since the resin pool is not formed as in the conventional case, it is not necessary to remove the resin pool after injection molding of the seal ring, and the man-hours and materials can be reduced.

Further, by arranging the position of the gate on the opposite portion of the abutment portion, the amount of resin flowing on both the left and right sides of the seal ring main body 1A becomes the same, and the internal pressure of the molten resin in the mold is reduced, so that burrs and the like are generated. Can also be prevented.

Further, in the above-described embodiment, as shown in FIG. 6, in the joint portion 15, both ends of the seal ring main body 1A are formed in a stepped shape so as to engage with each other. , Not limited to its configuration.
For example, it may be configured as shown in the plan view of the joint portion 15 of FIG. 7 (a) and the side view of FIG. 7 (b). That is, on the inner peripheral surface of the seal ring, an inner peripheral side wall 15 g extending in a wall shape in the circumferential direction is formed on one end side of the seal ring main body 1A. Further, on the radial outer side of the inner peripheral side wall 15g, an engaging convex portion 15h extending in the circumferential direction in a stepped shape is formed. By forming the engaging convex portion 15h, an upper recess 15i (engaging recess) and a lower recess 15j (engaging recess) are formed above and below the engaging convex portion 15h, respectively.

On the other hand, on the other end side of the seal ring main body 1A, an inner peripheral side recess 15k formed so that the inner peripheral side wall 15g can be engaged is formed on the inner peripheral surface of the seal ring.
Further, on the radial outer side of the inner peripheral side concave portion 15k, the upper convex portion 15m (engaging convex portion) that can be engaged vertically and vertically with the engaging convex portion 15h and engages with the upper concave portion 15i and the lower concave portion 15j, respectively. ), The lower convex portion 15n (engaged convex portion) is extended.
By forming the upper convex portion 15m and the lower convex portion 15n, an intermediate concave portion 15p (engaging concave portion) is formed between them, and the engaging convex portion 15h engages there.

In this way, in the abutment portion 15, both ends of the seal ring main body 1A may be formed in a concavo-convex shape facing each other so as to engage with each other.
Even in this case, when the abutment portion 15 is closed, the first sealing surface 2 which is the sealing surface and the non-sealing surface 6 do not communicate with each other, and the second sealing surface 5 and the non-sealing surface 7 do not communicate with each other. It becomes a state and the sealing performance is improved.

In the above embodiment, as shown in FIG. 3, a case where six tabs 10 are provided on the seal ring 1 is shown, but in the present invention, the number of tabs 10 is particularly limited to six. It's not a thing.
Further, in the above embodiment, the case where the seal ring is injection-molded with the resin containing the filler fiber has been described, but the present invention is not limited to this, and the seal ring is formed with the resin containing no filler fiber. It can also be applied to injection molding.

(Example 1)
The following seal ring was manufactured by injection molding.
This seal ring has a step-shaped abutment portion as shown in FIG. 6, is made of polyetheretherketone (PEEK), has an outer diameter of φ50 mm, and has an inner diameter of φ46 mm.
The length of the filler fiber contained in the resin forming the seal ring is 1000 μm or less, the average length is 200 μm, the number of tabs 10 is 6, and the most from the end of the abutment to the end of the abutment. The length dimension L1 to the end of the near tab is 1 mm, the radial thickness dimension L2 of the tab is 0.5 mm, the radial thickness dimension L3 of the seal ring body is 2 mm, and the inclination angle θ of the tab side surface is 120 degrees. Is.
Then, using a micrometer, the maximum and minimum values of the axial thickness at 10 points of the seal ring main body in one of the seal rings were measured, and the difference was obtained as the flatness.
As a result, the flatness was 0.014 (mm).

(Example 2)
A seal ring was manufactured by injection molding under the same conditions as in Example 1 above, except that the length dimension L1 from the end of the abutment to the end of the tab closest to the end of the abutment was 0.5 mm.
Then, using a micrometer, the maximum and minimum values of the axial thickness at 10 points of the seal ring main body in one of the seal rings were measured, and the difference was obtained as the flatness.
As a result, the flatness was 0.01 (mm).

(Example 3)
A seal ring was manufactured by injection molding under the same conditions as in Example 1 above, except that the length dimension L1 from the end of the abutment to the end of the tab closest to the end of the abutment was 1.5 mm.
Then, using a micrometer, the maximum and minimum values of the axial thickness at 10 points of the seal ring main body in one of the seal rings were measured, and the difference was obtained as the flatness.
As a result, the flatness was 0.017 (mm).

(Example 4)
A seal ring was manufactured by injection molding under the same conditions as in Example 1 above, except that the length dimension L1 from the end of the abutment to the end of the tab closest to the end of the abutment was 2.5 mm.
Then, using a micrometer, the maximum and minimum values of the axial thickness at 10 points of the seal ring main body in one of the seal rings were measured, and the difference was obtained as the flatness.
As a result, the flatness was 0.019 (mm).

(Example 5)
As the fifth embodiment, the length dimension L1 from the end of the abutment portion to the end of the tab closest to the end of the abutment portion is set to 0.3 mm, and the seal ring is manufactured under the same conditions as in the first embodiment described above. I tried, but the length from the end of the mold to the end of the tab closest to the end of the mold was short, and the shape of the mold's joint became complicated, so I gave up making the mold.

(Comparative Example 1)
As Comparative Example 1, a seal ring similar to that of Example 1 was manufactured except that the tab in Example 1 was not formed. Then, in the same manner as in Example 1, the maximum value and the minimum value of the axial thickness at 10 points of the seal ring main body in one of the seal rings were measured, and the difference was obtained as the flatness.
As a result, the flatness was 0.024 (mm).

(Comparative Example 2)
A seal ring was manufactured by injection molding under the same conditions as in Example 1 above, except that the length dimension L1 from the end of the abutment to the end of the tab closest to the end of the abutment was set to 3 mm.
Then, using a micrometer, the maximum and minimum values of the axial thickness at 10 points of the seal ring main body in one of the seal rings were measured, and the difference was obtained as the flatness.
As a result, the flatness was 0.024 (mm).

As described above, the flatness is not measured in Example 5, but even when the length dimension from the end of the abutment portion to the end of the tab closest to the end of the abutment portion is short as in Example 5. It can be inferred that the effect of reducing the internal pressure of the mold can be obtained by allowing the molten resin to flow into the tab forming portion of the mold.
However, if the length dimension from the end of the abutment to the end of the tab closest to the end of the abutment is too short as in the fifth embodiment, the shape of the abutment becomes complicated and it becomes difficult to manufacture the mold. Therefore, it is not preferable from the viewpoint of mold manufacturing.
Further, as compared with the seal rings of Examples 1 to 4 and the seal rings of Comparative Examples 1 and 2 in which the tabs are formed at least in the vicinity of the abutment portion, the seal rings of Examples 1 to 4 are superior in flatness. Since the flatness is excellent, it can be said that the sealing performance is also excellent.
Therefore, it was confirmed that the flatness and the sealing property are improved by forming the tab at least in the vicinity of the abutment portion.

1 Seal ring 1A Seal ring body 2 1st seal surface 5 2nd seal surface 6 Non-seal surface 7 Inner peripheral surface 10 Tab 15 Abutment 20 Shaft 21 Circular groove 21a Side surface (oil seal side)
22 Gap 30 Housing 31 Inner peripheral surface of housing

Claims (8)

In a resin seal ring containing filler fibers, which is a seal ring that seals an annular gap between a housing and a shaft assembled inside the housing and does not form a resin pool during molding.
An annular seal ring body with a joint and
A plurality of tabs formed so as to project radially inward on the inner peripheral surface of the seal ring body are provided.
The tab is a seal ring characterized in that it is formed at least in the vicinity of the abutment portion. The length dimension from the end of the abutment, which is the position where the cross-sectional shape changes in the abutment, to the end of the tab closest to the end of the abutment is 0.5 mm or more and 2.5 mm or less. The seal ring according to claim 1. The seal ring according to claim 1 or 2, wherein the filler fiber has a length dimension of 1000 μm or less. The cross-sectional area parallel to the axis of the tab and the seal ring body at the position of the tab formed in the vicinity of the abutment portion is parallel to the axis of the seal ring body at the positions on both the left and right sides of the tab. The seal ring according to any one of claims 1 to 3, wherein the seal ring is larger than the cross-sectional area. In the abutment portion, one end and the other end of the seal ring main body face each other, and the abutment portion is opposed to each other.
Further, on the one end portion and the other end portion, an engaging convex portion capable of engaging with each other is formed so that the cross-sectional area parallel to the axis is smaller than the cross-sectional area parallel to the axis of the seal ring main body other than the abutment portion. The seal ring according to any one of claims 1 to 4, wherein an engaging recess is formed. The invention according to any one of claims 1 to 5, wherein the inclination angle of the side surface of the tab with respect to the inner peripheral surface of the seal ring main body is set within a range of 100 ° or more and 150 ° or less. Seal ring. The seal ring according to any one of claims 1 to 6, wherein the radial thickness dimension of the tab is formed to be smaller than the radial thickness dimension of the seal ring main body. .. The seal ring main body is formed so as to be mountable in an annular groove formed in a shaft inserted inside the housing, and at the time of mounting, the tip of the plurality of tabs hits the groove bottom surface of the annular groove. The seal ring according to any one of claims 1 to 7, wherein the seal ring is formed so as to be contactable.

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