CN216843099U

CN216843099U - Sealing ring

Info

Publication number: CN216843099U
Application number: CN202121985223.XU
Authority: CN
Inventors: 大锯哲平; 小山哲司; 筱原知来
Original assignee: TPR Co Ltd
Current assignee: TPR Co Ltd
Priority date: 2020-09-30
Filing date: 2021-08-23
Publication date: 2022-06-28
Anticipated expiration: 2031-08-23
Also published as: CN114321377A

Abstract

The utility model provides a sealing ring, in the sealing ring of resin system, need not form the resin that has removed after the shaping like in the past and store up the portion to, flatness, leakproofness are good. The utility model discloses a sealing ring (1) is to the casing and assemble sealing ring (1) of the resin system that seals up between the inside axle of this casing, possesses at least: an annular seal ring main body (1A) having a joint section (15); and a plurality of protruding pieces (10) that are formed on the inner circumferential surface side of the seal ring main body (1A) and protrude radially inward. The tab (10) is formed in the vicinity of the engaging portion (15).

Description

Sealing ring

Technical Field

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

Background

For example, a plurality of seal rings are used in an Automatic Transmission (AT) for an automobile. The annular seal ring 100 shown in fig. 8 and 9 is assembled between the shaft 300 and the housing 200 that move relatively in the hydraulic circuit of the transmission, and functions to seal the lubricating oil while sliding.

As shown in fig. 8, in the seal ring 100, protruding pieces 101 protruding radially inward may be provided at a plurality of positions on the inner circumferential surface 100a side of the seal ring 100.

The function of the tab 101 is: when the shaft 300 is assembled inside the housing 200, the tip end thereof is brought into contact with the groove bottom surface of the annular groove 301, thereby preventing the center of the seal ring 100 from being largely deviated from the shaft center.

As shown in fig. 8, the seal ring 100 is formed with a joint portion 102. The joint portion 102 is formed by cutting a part of the seal ring 100, and when the seal ring is attached to the shaft 300, the joint portion 102 is spread and attached.

As the seal ring, a seal ring formed by injection molding a material in which a reinforcing material (referred to as a filler fiber) such as a carbon fiber is blended with Polyamide (PA), a fluororesin (polytetrafluoroethylene (4-fluorinated) (PTFE), a tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), a tetrafluoroethylene/ethylene copolymer (ETFE), or the like), an alloy material thereof, a Liquid Crystal Polymer (LCP), Polyimide (PI), polyether ketone (PEK), polyarylether ketone (PAEK), polyether ketone ether ketone (PEKEKK), polyether ether ketone (PEEK), or polyphenylene sulfide (PPS), or Polybenzimidazole (PBI), into a ring shape, is often used.

In addition, as for injection molding of a seal ring, patent document 1 proposes, as shown in fig. 10, the following: the gate 153 is disposed at a position shifted from the opposing portion 152 of the seal ring 150 of the joint portion 151, and a resin reservoir 154 is provided on the side (flow length T1 side) where the distance between the gate 153 and the joint portion 151 is short.

With this configuration, in the method for manufacturing the seal ring 150 disclosed in patent document 1, the resin filling amount can be made the same for the longer distance between the gate 153 and the joint 151 (on the side of the flow length T2) and the shorter distance between the gate 153 and the joint 151 (on the side of the flow length T1), the resin can be appropriately filled, and occurrence of defects such as burrs can be prevented.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. 2004-205003

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved by the utility model

However, even when the gate is disposed at the opposing portion of the joint portion, there is a problem that the thickness in the vicinity of the joint portion becomes thicker than the other portion of the seal ring main body when the seal ring is actually molded by injection molding of a resin containing a filler fiber.

Specifically, this phenomenon will be described with reference to fig. 11 and 12. Fig. 11 (a) is a cross-sectional view perpendicular to the axis of the seal ring main body at a position other than the vicinity of the joint portion of the seal ring main body. Fig. 11 (b) is a partially enlarged view of fig. 11 (a). Fig. 12 (a) is a cross-sectional view perpendicular to the axis of the seal ring main body in the vicinity of the joint portion of the seal ring main body. Fig. 12 (b) is a partially enlarged view of fig. 12 (a).

As shown in fig. 11 (b), the filling fiber F at a position other than the vicinity of the joint portion of the seal ring main body was visually observed to be elongated, and the axis of the filling fiber F was oriented so as to be perpendicular to the axis of the seal ring main body (the axis of the filling fiber F was oriented parallel to the flow direction of the molten resin).

In contrast, in fig. 12 (b), the state in which the axis of the filler fiber F is oriented in the perpendicular direction with respect to the axis of the seal ring main body as in fig. 11 (b) cannot be visually confirmed.

That is, it is found that, in the filler fibers in the vicinity of the joint portion of the seal ring main body, the axis of the filler fibers is oriented in a direction perpendicular to the flow direction of the molten resin.

The above phenomenon is caused by the resin colliding with the joining end of the mold corresponding to the end of the joining portion of the seal ring main body in the mold, and the orientation of the filler fibers is disturbed. In the vicinity of the joint portion of the seal ring, the filler fibers are oriented in a direction perpendicular to the flow direction of the molten resin, and therefore the cure shrinkage rate of this portion is smaller than that of the other portion (a portion other than the vicinity of the joint portion). As a result, the thickness near the joint portion is thicker than other portions.

In this way, the thickness in the vicinity of the joint portion is thicker than the other positions of the seal ring main body, and this further deteriorates the flatness of the seal ring main body, which causes a problem of lowering the sealing performance of the seal ring.

Further, when the sealing ring is formed by arranging a gate at a position of the mold corresponding to the facing portion of the joint portion of the sealing ring main body and injection molding the fiber-filled resin from the gate, the resin bank must be removed with high accuracy after the injection molding if the resin bank as described above is formed, and a large number of steps and materials are required, which causes a problem of cost.

The utility model discloses a solve above-mentioned technical problem and accomplish, its aim at provides such a sealing ring, promptly: in the sealing ring made of the resin mixed with the filling fiber, the resin storage part removed after the injection molding in the prior art does not need to be formed, and the flatness and the sealing performance are good.

Means for solving the problems

In order to solve the above problem, the utility model discloses a sealing ring is the sealing ring that seals the annular gap between the axle of casing inside with assembling to the casing, and, the sealing ring is that the sealing ring that is made by the resin that cooperates with the infill fibre that does not form the resin and stores up the portion when injection moulding, its characterized in that possesses: an annular seal ring main body having a joint portion; and a plurality of protruding pieces formed on an inner peripheral surface of the seal ring main body and protruding radially inward, the protruding pieces being formed at least in the vicinity of the engaging portion.

As described above, the seal ring of the present invention includes the plurality of protruding pieces formed on the inner peripheral surface of the seal ring main body and protruding radially inward, and the protruding pieces are formed at least in the vicinity of the joint portion, so that, at the time of injection molding of the seal ring, the molten resin flows into the protruding piece forming portion of the mold, and the mold internal pressure in the mold region corresponding to the vicinity of the joint portion of the seal ring main body is reduced.

As described above, the curing shrinkage rate tends to be small in the vicinity of the joint portion where the orientation of the filler is disturbed, with respect to the position other than the vicinity of the opening portion.

Further, the mold internal pressure is reduced in the vicinity of the joint portion, and the curing shrinkage rate tends to increase due to the reduction in the mold internal pressure. Therefore, in the vicinity of the joint portion, a decrease in the curing shrinkage rate due to disorder of the filler orientation and an increase in the curing shrinkage rate due to a decrease in the mold internal pressure are offset.

As a result, the curing shrinkage rates of the vicinity of the joint portion and the other position of the seal ring main body become substantially the same, the thickness of the vicinity of the joint portion and the thickness of the other position of the seal ring main body become substantially uniform, and the flatness and the sealing property of the seal ring can be improved.

Further, since the conventional resin reservoir is not formed, it is not necessary to remove the resin reservoir after the injection molding of the seal ring, and the number of steps and the material can be reduced.

Preferably, a length dimension from the joint end to an end of the tab closest to the joint end is 0.5mm or more and 2.5mm or less.

When the length from the joining portion end to the end of the projecting piece closest to the joining portion end exceeds 2.5mm, the length increases, and therefore the effect of reducing the pressure inside the mold due to the molten resin flowing into the projecting piece forming portion of the mold is small.

On the other hand, even if the length from the joining portion end to the end of the projecting piece closest to the joining portion end is less than 0.5mm, the effect of reducing the pressure drop in the mold due to the molten resin flowing into the projecting piece forming portion of the mold can be obtained, but if the length is less than 0.5mm, the shape of the joining portion becomes complicated, and the mold is difficult to manufacture, which is not preferable.

The length of the filler fiber is preferably 1000 μm or less.

When the length of the filler fiber exceeds 1000 μm, the shrinkage anisotropy at the time of injection molding becomes strong, which is not preferable. Preferably, the average length of the filler fibers is about 200 μm.

In addition, it is preferable that a cross-sectional area parallel to an axis of the seal ring main body at a position of the protruding piece formed in the vicinity of the joint portion is larger than a cross-sectional area parallel to an axis of the seal ring main body at positions on both left and right sides of the protruding piece.

In this way, since the cross-sectional area parallel to the axis where the protruding piece and the seal ring main body overlap 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 protruding piece, the mold internal pressure in the mold region corresponding to the vicinity of the joint portion can be reduced.

In the joint portion, one end portion and the other end portion of the seal ring main body preferably face each other, and an engaging convex portion or an engaging concave portion that can be engaged with each other is formed at the one end portion and the other end portion, and a cross-sectional area parallel to an axis of the seal ring main body of the engaging convex portion or the engaging concave portion is preferably smaller than a cross-sectional area parallel to the axis of the seal ring main body.

In this way, even if the engaging convex portion or the engaging concave portion having a smaller cross-sectional area parallel to the axis than the cross-sectional area parallel to the axis of the seal ring main body is formed at the one end portion and the other end portion of the joint portion, the mold internal pressure in the mold region corresponding to the vicinity of the joint portion of the seal ring main body is reduced by the molten resin flowing into the protruding piece forming portion of the mold at the time of injection molding of the seal ring.

Therefore, as described above, the curing shrinkage rate tends to decrease in the vicinity of the joint portion where the orientation of the filler is disturbed, but the curing shrinkage rate tends to increase in the vicinity of the joint portion due to a decrease in the mold internal pressure.

As a result, in the vicinity of the joint portion, a decrease in the curing shrinkage rate due to disturbance in the orientation of the filler and an increase in the curing shrinkage rate due to a decrease in the internal pressure of the mold are cancelled out, and the thickness in the vicinity of the joint portion and the thickness at other positions of the seal ring main body become substantially uniform, thereby making it possible to improve the flatness and the sealing property of the seal ring.

Preferably, an inclination angle of the side surface of the protruding piece with respect to the circumferential direction of the seal ring main body is set in a range of 100 ° to 150 °.

When the inclination angle of the side surface of the tab is smaller than 100 °, the orientation of the filler fibers in the tab is likely to be disturbed, which is not preferable. Further, when the inclination angle of the side surface of the tab exceeds 150 °, the circumferential length of the tab becomes longer, and the cure shrinkage rate becomes larger at a position other than the vicinity of the joint portion, which is not preferable because it causes deterioration of flatness.

Preferably, the radial thickness dimension of the tab is smaller than the radial thickness dimension of the seal ring main body.

When the radial thickness dimension of the seal ring main body is smaller than the radial thickness dimension of the protruding piece, the mechanical strength of the seal ring main body is reduced, which is not preferable.

Preferably, the seal ring main body is attachable to an annular groove formed in a shaft insertable into the housing, and the distal ends of the plurality of projecting pieces are capable of abutting against a groove bottom surface of the annular groove when the seal ring main body is attached.

Effect of utility model

According to the present invention, in the seal ring made of the resin containing the filler fibers, it is not necessary to form the resin reservoir portion which has been removed after the injection molding as in the conventional case, and the seal ring having excellent flatness and sealing performance can be obtained.

Drawings

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 viewed from another direction.

Fig. 3 (a) is a plan view of the seal ring of fig. 1 and 2, and fig. 3 (b) 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 attached to the annular groove of the shaft.

Fig. 5 (a) is an enlarged perspective view showing the engaging portion and the projecting piece in the vicinity thereof, and fig. 5 (b) is an I-I sectional view of fig. 5 (a).

Fig. 6 (a) is a plan view of the joint and the protruding piece in the vicinity thereof, as viewed in an enlarged manner, and fig. 6 (b) is a side view of the joint as viewed from the outside of the seal ring.

Fig. 7 shows another form of the joint portion, in which fig. 7 (a) is a plan view of the joint portion and the protruding piece in the vicinity thereof, as viewed in an enlarged manner, and fig. 7 (b) is a side view of the joint portion as viewed from the outside of the seal ring.

Fig. 8 is a perspective view of a conventional seal ring.

Fig. 9 is a cross-sectional view parallel to the axis of the seal ring main body in a state where the shaft to which the conventional seal ring is attached is assembled to the housing.

Fig. 10 is a plan view of a conventional seal ring.

Fig. 11 is a structural view of a conventional seal ring, in which fig. 11 (a) is a cross-sectional view perpendicular to the axis of the seal ring main body at a position other than the vicinity of the joint portion of the seal ring main body, and fig. 11 (b) is a partial enlarged view of fig. 11 (a).

Fig. 12 is a structural view of a conventional seal ring, in which fig. 12 (a) is a cross-sectional view perpendicular to the axis of a seal ring main body in the vicinity of a joint portion of the seal ring main body, and fig. 12 (b) is a partially enlarged view of fig. 12 (a).

Detailed Description

Hereinafter, embodiments of the seal ring according to the present invention will be described with reference to the drawings. The seal ring according to the present embodiment is incorporated between a shaft and a housing that move relatively in a hydraulic circuit of an automatic transmission of an automobile, for example, and functions to seal 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. Fig. 3 (a) is a plan view of the seal ring of fig. 1 and 2, and fig. 3 (b) 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 attached to the annular groove of the shaft.

The axis of the seal ring main body is a line extending in the vertical direction with respect to a plane including the first seal surface of the seal ring, through the center C (center of the circular ring) of the annular seal ring in a state where the seal ring according to the embodiment of the present invention is attached to the annular groove of the shaft.

The illustrated seal ring 1 includes: an annular seal ring main body 1A for sealing a gap between the housing and the shaft, which is formed of a super engineering plastic represented by Polyamide (PA), fluororesin (polytetrafluoroethylene (4-fluoro) (PTFE), tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene/ethylene copolymer (ETFE), etc.) and alloy materials thereof, Liquid Crystal Polymer (LCP), Polyimide (PI), polyether ketone (PEK), polyarylether ketone (PAEK), polyether ketone ether ketone (PEKEKK), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), etc., and a material obtained by blending filler fibers such as carbon fibers as a reinforcing material with Polybenzimidazole (PBI); and a plurality of protruding pieces 10 formed on the inner peripheral surface of the seal ring main body 1A. The seal ring main body 1A is formed to have a rectangular cross section parallel to the axis of the seal ring main body at a position where the protruding piece 10 is not formed.

The seal ring 1 is a seal ring made of resin that does not form the resin reservoir shown in patent document 1. In addition, as described above, since the resin does not contain the filler fiber in the seal ring 1, the seal ring has high wear resistance.

More specifically, as shown in fig. 4, the first seal surface 2 is provided on the oil seal side (seal surface side) of the seal ring main body 1A. The first seal surface 2 is in sliding contact with a side wall surface (oil seal side surface of the annular groove) 21a of the annular groove 21 of the shaft 20, and seals the side wall surface 21 a.

Further, the outer peripheral surface of the seal ring main body 1A is a second seal surface 5. The second seal surface 5 is in contact with the inner peripheral surface 31 of the housing 30, and seals.

As described above, at the inner peripheral surface 7 of the seal ring 1 shown in fig. 1 to 3, a plurality of (6 in the drawings) protruding pieces 10 are provided at predetermined intervals.

As shown in fig. 3, each protruding piece 10 protrudes radially inward from the inner peripheral surface 7, and as shown in fig. 4, when the seal ring 1 is mounted in the annular groove 21 of the shaft 20 and the seal ring body 1A and the shaft 20 are offset in center, the tip end portion 10a of the protruding piece 10 abuts against the groove bottom surface 21b of the annular groove 21.

As described above, one of the functions of the protruding piece 10 is to prevent the center C of the seal ring main body 1A from being greatly deviated from the center of the shaft 20 when the shaft 20 is assembled inside the housing 30.

As shown in fig. 1 to 3, an engagement 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 seal ring 1 is easily attached to the annular groove 21 of the shaft 20 by expanding the seal ring in a direction of separating the engagement portion 15.

The tabs 10 are provided at least in the vicinity of both ends of the seal ring main body 1A separated by the engaging portions 15, respectively.

Specifically, the protruding piece 10 is provided at least in the vicinity of an end portion of the joint portion 15 of the seal ring main body 1A (a position where the cross-sectional area changes in the joint portion 15).

Thus, when the seal ring 1 is injection molded, the molten resin containing the filler fibers flows into the protruding piece forming portion of the mold, and the mold internal pressure in the mold region corresponding to the vicinity of the joint portion of the seal ring main body 1A is reduced.

As described above, the curing shrinkage rate tends to be small in the vicinity of the joint portion where the orientation of the filler is disturbed, with respect to the positions other than the vicinity of the joint portion. In the vicinity of the joint, the mold internal pressure is reduced, and the curing shrinkage rate tends to increase due to the reduction in the mold internal pressure.

Therefore, in the vicinity of the joint portion, a decrease in the curing shrinkage rate due to disturbance of the orientation of the filler and an increase in the curing shrinkage rate due to a decrease in the mold internal pressure are offset.

The length of the filler fibers contained in the resin forming the seal ring 1 is preferably 1000 μm or less. When the length of the filler fiber exceeds 1000 μm, the shrinkage anisotropy at the time of injection molding becomes strong, which is not preferable.

The average length of the filler fibers is preferably about 200 μm.

The filler fiber is not limited to the above length, and may be in any shape or size as long as it can exert the effect of abrasion resistance. In addition, although carbon fibers are exemplified as the filler fibers, the present invention is not limited to carbon fibers, and glass fibers or CNF (cellulose nanofibers) may be used, for example.

Next, the structure of the engaging portion 15 and the protruding piece 10 will be described in detail.

Fig. 5 (a) is a perspective view showing the engaging portion 15 and the projecting piece 10 in the vicinity thereof in an enlarged manner, and fig. 5 (b) is a cross-sectional view taken along line I-I of fig. 5 (a). Fig. 6 (a) is a plan view of the joint 15 and the protruding piece 10 in the vicinity thereof, in an enlarged manner, and fig. 6 (b) is a side view of the joint 15 viewed from the outside of the seal ring body 1A.

The joint portion 15, that is, the position where one end portion and the other end portion of the seal ring main body 1A face each other, has an engaging convex portion or an engaging concave portion that can be engaged with each other, and a cross-sectional area parallel to the axis of the engaging convex portion or the engaging concave portion is smaller than a cross-sectional area parallel to the axis of the seal ring main body 1A.

Specifically, an inner peripheral side wall 15a extending in a wall shape in the circumferential direction is formed on one end side of the seal ring main body 1A on the inner peripheral surface of the seal ring main body 1A.

Further, radially outward of the inner peripheral sidewall 15a, a lower section 15b is formed to extend in a stepped manner in the circumferential direction. By forming the lower stage portion 15b, an upper stage recess 15c is formed thereon.

On the other hand, an inner peripheral side recessed portion 15d is formed on the other end side of the seal ring main body 1A, and the inner peripheral side recessed portion 15d is formed so as to be engageable with the inner peripheral side wall 15a on the inner peripheral surface of the seal ring main body 1A.

Further, an upper step portion 15e is provided to extend radially outward of the inner peripheral recessed portion 15d, and the upper step portion 15e is formed to be engageable with the lower step portion 15b and to be engageable with the upper recessed portion 15 c.

Further, by forming the upper stage portion 15e, a lower stage recess portion 15f is formed therebelow, and the lower stage portion 15b is engaged therewith.

In this way, in the joint portion 15, both end portions of the seal ring main body 1A are formed in a stepped shape, and by the structure of the engagement with each other, in a state where the joint portion 15 is closed, the first seal surface 2 as the seal surface is not in communication with the non-seal surface 6, and the second seal surface 5 is not in communication with the non-seal surface 7, and the sealing performance is improved.

As shown in fig. 6 (a), the protruding piece 10 is provided at least in the vicinity of the end of the joint portion 15 of the seal ring body 1A (the position where the cross-sectional area changes in the joint portion 15), as described above. Preferably, a length L1 from an end of the engaging portion 15 to an end of the tab 10 closest to the end of the engaging portion 15 is 0.5mm to 2.5 mm.

The length L1 from the end of the joint 15 to the tab 10 closest thereto is a length from the position (joint end) where the cross-sectional shape changes in the joint 15 of the seal ring body 1A to the tab 10 closest thereto, where both ends of the seal ring body 1A are formed in a stepped shape.

Further, when the length from the joining portion end to the end of the projecting piece closest to the joining portion end exceeds 2.5mm, the length increases, and therefore, the effect of reducing the pressure drop in the mold due to the molten resin flowing into the projecting piece forming portion of the mold is small.

In addition, an inclination angle of the side surface of the protruding piece with respect to the circumferential direction of the seal ring main body is set within a range of 100 ° to 150 °.

When 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. Further, when the inclination angle of the side surface of the tab exceeds 150 °, the circumferential length of the tab becomes longer, and the cure shrinkage rate becomes larger at a position other than the vicinity of the joint portion, which is not preferable because it causes deterioration of flatness.

As shown in fig. 6 (a), the radial thickness L2 of the tab 10 is smaller than the radial thickness L3 of the seal ring body 1A.

When the radial thickness L3 of the seal ring main body is smaller than the radial thickness L2 of the protruding piece, the radial thickness of the seal surface 2 of the seal ring main body 1A becomes smaller, and the sealing performance is lowered, which is not preferable.

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 protruding piece 10.

As shown in fig. 5b, the cross-sectional area S1 parallel to the axis where the tab 10 overlaps the seal ring main body 1A is larger than the cross-sectional area S2 parallel to the axis of the seal ring main body 1A at the left and right sides of the tab 10 (the position where the tab is not formed).

Thus, during injection molding of the seal ring 1, the molten resin containing the filler fibers flows into the protruding piece forming portion of the mold, and the mold internal pressure in the region of the mold corresponding to the vicinity of the joint portion is reduced.

The seal ring 1 configured as described above is obtained by injecting a molten resin containing a filler fiber into a mold (not shown).

A gate into which the resin flows in the mold is formed at a position of the mold corresponding to an opposing 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 opposite portion of the joint portion 15 of the seal ring 1.

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

As described above, the molten resin flowing from the gate to both the left and right sides also flows into the protruding piece forming portion of the mold corresponding to the protruding piece 10.

Since the projecting piece forming portion is provided near the joining portion forming portion of the mold corresponding to the joining portion 15, the molten resin passing through the projecting piece forming portion, that is, the internal mold pressure of the molten resin near the opening portion forming portion is reduced by the projecting piece forming portion.

As described above, the curing shrinkage rate tends to be small in the vicinity of the joint portion where the orientation of the filler is disturbed, with respect to the positions other than the vicinity of the joint portion.

Further, since the die internal pressure of the molten resin in the vicinity of the joint portion forming portion is reduced by the protruding portion forming portion, the solidification shrinkage rate tends to increase due to the reduction in the die internal pressure.

Therefore, in the vicinity of the joint portion, a decrease in the curing shrinkage rate due to disorder in the orientation of the filler and an increase in the curing shrinkage rate due to a decrease in the internal pressure of the mold are offset.

As a result, the thickness in the vicinity of the joint portion and the thickness at other positions of the seal ring main body are substantially uniform, and the flatness and the sealing property of the seal ring can be improved.

Further, since the resin bank is not formed as in the conventional case, it is not necessary to remove the resin bank after the injection molding of the seal ring, and the number of steps and the material can be reduced.

Further, by arranging the gate at the opposing portion of the joint portion, the amount of resin flowing to both the left and right sides of the seal ring main body 1A becomes the same, and the mold internal pressure of the molten resin is reduced, so that the generation of burrs and the like can also be prevented.

In the above embodiment, as shown in fig. 6, the joint portion 15 has a structure in which both end portions of the seal ring main body 1A are formed in a stepped shape and engaged with each other.

For example, the structure may be such that the joint 15 is shown in a plan view in fig. 7 (a) and in a side view in fig. 7 (b). That is, an inner peripheral side wall 15g extending in a wall-like manner in the circumferential direction is formed on the seal ring inner peripheral surface on the one end side of the seal ring main body 1A. Further, radially outward of the inner peripheral side wall 15g, an engaging convex portion 15h extending in a stepwise manner in the circumferential direction is formed. By forming the engaging convex portion 15h, an upper stage concave portion 15i (engaging concave portion) and a lower stage concave portion 15j (engaging concave portion) are formed on the upper and lower sides thereof, respectively.

On the other hand, an inner peripheral recessed portion 15k is formed on the other end side of the seal ring main body 1A, and the inner peripheral recessed portion 15k is formed so as to be engageable with the inner peripheral side wall 15g on the seal ring inner peripheral surface.

Further, an upper-stage convex portion 15m (engaging convex portion) and a lower-stage convex portion 15n (engaging convex portion) which can engage with the upper and lower portions of the engaging convex portion 15h and engage with the upper-stage concave portion 15i and the lower-stage concave portion 15j, respectively, extend radially outward from the inner peripheral side concave portion 15 k.

Further, by forming the upper-stage convex portion 15m and the lower-stage convex portion 15n, an intermediate concave portion 15p (engaging concave portion) is formed therebetween, and the engaging convex portion 15h is engaged thereto.

As described above, the joint portion 15 may have a structure in which: both end portions of the seal ring main body 1A are formed in opposing concave-convex shapes and engaged with each other.

In this case, in the state where the joint 15 is closed, the first seal surface 2, which is the seal surface, is not in communication with the non-seal surface 6, and the second seal surface 5 is not in communication with the non-seal surface 7, so that the sealing performance is improved.

In the above embodiment, as shown in fig. 3, the case where 6 protruding pieces 10 are provided in the seal ring 1 is shown, but in the present invention, the number of protruding pieces 10 is not particularly limited to 6.

In addition, in the above-described embodiment, the case where the seal ring is injection-molded using the resin containing the filler fiber has been described, but the present invention is not limited thereto, and can be applied to the case where the seal ring is injection-molded using the resin not containing the filler fiber.

(example 1)

The following seal ring was produced by injection molding.

The seal ring has a stepped joint portion shown in FIG. 6, and is made of polyether ether ketone (PEEK) and has an outer diameter of

An inner diameter of

The filling fiber contained in the resin forming the seal ring has a length of 1000 μm or less, an average length of 200 μm, 6 tabs 10, a length L1 from the joint end to the end of the tab closest to the joint end of 1mm, a radial thickness L2 of the tab of 0.5mm, a radial thickness L3 of the seal ring body of 2mm, and an inclination angle θ of the tab side surface of 120 degrees.

Then, the maximum value and the minimum value of the thicknesses in the axial direction at 10 positions of the seal ring main body of 1 seal ring were measured using a micrometer, and the difference was obtained as the flatness.

As a result, the flatness was 0.014 (mm).

(example 2)

A seal ring was produced by injection molding under the same conditions as in example 1, except that the length L1 from the joint end to the end of the tab closest to the joint end was set to 0.5 mm.

As a result, the flatness was 0.01 (mm).

(example 3)

A seal ring was produced by injection molding under the same conditions as in example 1, except that the length L1 from the joint end to the end of the tab closest to the joint end was set to 1.5 mm.

As a result, the flatness was 0.017 (mm).

(example 4)

A seal ring was produced by injection molding under the same conditions as in example 1, except that the length L1 from the joint end to the end of the tab closest to the joint end was set to 2.5 mm.

As a result, the flatness was 0.019 (mm).

(example 5)

In example 5, the production of the seal ring was attempted under the same conditions as in example 1 except that the length L1 from the joining portion end to the end of the protruding piece closest to the joining portion end was set to 0.3mm, but the length from the joining end of the mold to the end of the protruding piece closest to the joining end was short, and the joining shape of the mold became complicated, and the production of the mold was abandoned.

Comparative example 1

As comparative example 1, a seal ring was produced in the same manner as in example 1, except that the protruding piece in example 1 was not formed. Then, the maximum value and the minimum value of the thickness in the axial direction at 10 positions of the seal ring main body of 1 seal ring were measured in the same manner as in example 1, and the difference was obtained as the flatness.

As a result, the flatness was 0.024 (mm).

Comparative example 2

A seal ring was produced by injection molding under the same conditions as in example 1, except that the length L1 from the joint end to the end of the protruding piece closest to the joint end was 3 mm.

As a result, the flatness was 0.024 (mm).

As described above, the flatness was not measured in example 5, but it is presumed that even in the case where the length from the joining portion end to the end of the projecting piece closest to the joining portion end is short as in example 5, the effect of reducing the pressure drop in the mold can be obtained by the molten resin flowing into the projecting piece forming portion of the mold.

However, as in example 5, if the length from the joining portion end to the end of the projecting piece closest to the joining portion end is too short, the shape of the joining portion becomes complicated, and the mold is difficult to manufacture, which is not preferable from the viewpoint of mold manufacturing.

In addition, when the seal rings of examples 1 to 4 in which the projecting pieces are formed at least in the vicinity of the joining portion are compared with the seal rings of comparative examples 1 and 2, the flatness of examples 1 to 4 is excellent. Further, 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 were improved by forming the protruding piece at least in the vicinity of the joining portion.

Description of the reference numerals

1 sealing ring

1A sealing ring body

2 first sealing surface

5 second sealing surface

6 non-sealing surface

7 inner peripheral surface

10 projecting piece

15 joint part

20 shaft

21 ring groove

21a side (oil seal side)

22 gap

30 casing

31 inner peripheral surface of the housing.

Claims

1. A seal ring for sealing an annular gap between a housing and a shaft assembled inside the housing, the seal ring being made of a fiber-filled resin without forming a resin reservoir during molding, the seal ring comprising:

an annular seal ring main body having a joint portion; and

a plurality of protruding pieces formed on the inner circumferential surface of the seal ring main body and protruding inward in the radial direction,

the tab is formed at least in the vicinity of the engaging portion.

2. The seal ring according to claim 1, wherein a length dimension from a position where a cross-sectional shape in the joint changes, that is, a joint end to an end of the tab closest to the joint end is 0.5mm or more and 2.5mm or less.

3. The seal ring of claim 1 or 2, wherein the length dimension of the filler fibers is 1000 μ ι η or less.

4. The seal ring according to claim 1 or 2, wherein a sectional area parallel to an axis where the tab and the seal ring main body overlap at a position of the tab formed in the vicinity of the engaging portion is larger than a sectional area parallel to an axis of the seal ring main body at positions on both left and right sides of the tab.

5. The seal ring according to claim 1 or 2,

at the joint portion, one end portion of the seal ring main body is opposed to the other end portion,

an engaging convex portion or an engaging concave portion that can be engaged with each other is formed at the one end portion and the other end portion, and a cross-sectional area parallel to an axis of the engaging convex portion or the engaging concave portion is smaller than a cross-sectional area parallel to an axis of the seal ring main body other than the joint portion.

6. The seal ring according to claim 1 or 2,

the side surface of the protruding piece is set to have an inclination angle in a range of 100 ° to 150 ° with respect to the inner circumferential surface of the seal ring main body.

7. The seal ring of claim 1 or 2, wherein a radial thickness dimension of the tab is less than a radial thickness dimension of the seal ring body.

8. The seal ring according to claim 1 or 2, wherein the seal ring main body is mountable in an annular groove formed in a shaft insertable into the housing, and wherein the plurality of projecting pieces have leading ends capable of abutting against a groove bottom surface of the annular groove when the mounting is performed.