sealing ring

Abstract

The present application provides a seal ring, in a resin seal ring, without the need to form the resin storage part removed after molding, and the flatness, sealing is good. The seal ring (1) of the present application is a resin seal ring (1) for sealing the annular gap between the housing and the shaft assembled inside the housing, at least comprising: a circular ring-shaped seal ring body (1A) having a joint (15); and a plurality of tabs (10) formed on the inner peripheral surface side of the seal ring body (1A) and protruding to the radial inner side. The tab (10) is formed near the joint (15).

Description

Technical Field

[0001] This invention relates to sealing rings, for example, to sealing rings used in automatic transmissions (AT) of automobiles for sealing lubricating oil in the gap between a shaft and a housing. Background Technology

[0002] For example, multiple sealing rings are used in automatic transmissions (AT) used in automobiles. Figure 8 and Figure 9 The annular sealing ring 100 shown is assembled between the shaft 300 and the housing 200, which move relative to each other in the hydraulic circuit of the transmission, and serves to seal the lubricating oil while sliding.

[0003] like Figure 8 As shown, in this sealing ring 100, sometimes a tab 101 protruding radially inward is provided at multiple positions on the inner circumferential surface 100a side of the sealing ring 100.

[0004] The function of the tab 101 is to prevent the center of the sealing ring 100 from deviating significantly from the center of the shaft by having its front end contact the bottom surface of the annular groove 301 when the shaft 300 is assembled inside the housing 200.

[0005] In addition, such as Figure 8 As shown, the sealing ring 100 has a joint portion 102. The joint portion 102 is formed by cutting a portion of the sealing ring 100, and is expanded during installation onto the shaft 300.

[0006] As a sealing ring, most are made by injection molding a ring-shaped material composed of reinforcing materials such as carbon fiber into a super engineering plastic represented by polyamide (PA), fluoropolymer (polytetrafluoroethylene (4-fluorinated) (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / ethylene copolymer (ETFE) etc.), liquid crystal polymer (LCP), polyimide (PI), polyether ketone (PEK), polyaryl ether ketone (PAEK), polyether ketone ketone ketone (PEKEKK), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polybenzimidazole (PBI), etc.

[0007] Furthermore, regarding the injection molding of the sealing ring, in Patent Document 1, such as Figure 10 As shown, the following solution is proposed: the gate 153 is positioned offset from the opposite portion 152 on the sealing ring 150 of the joint 151, and a resin accumulation portion 154 is provided on the side where the distance between the gate 153 and the joint 151 is shorter (flow length T1 side).

[0008] By adopting this structure, in the manufacturing method of the sealing ring 150 shown in Patent Document 1, the resin filling amount of the side with a longer distance between the gate 153 and the joint 151 (flow length T2 side) can be the same as that of the side with a shorter distance between the gate 153 and the joint 151 (flow length T1 side), so that the resin can be filled appropriately and the occurrence of defects such as burrs can be prevented.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2004-205003 Summary of the Invention

[0012] The technical problem that the invention aims to solve

[0013] However, even when a gate is provided at the opposite part of the joint, in practice, if the sealing ring is injection molded with resin containing filler fibers, there is a problem that the thickness near the joint is thicker than other parts of the sealing ring body.

[0014] Specifically, based on Figure 11 , Figure 12 This phenomenon will be explained. Figure 11 (a) is a cross-sectional view of the sealing ring body, taken at a location other than near the joint of the sealing ring body, and perpendicular to the axis of the sealing ring body. Figure 11 (b) in the middle is Figure 11 A magnified view of (a) in the image. Figure 12 (a) is a cross-sectional view near the joint of the sealing ring body, perpendicular to the axis of the sealing ring body. Figure 12 (b) in the middle is Figure 12 A magnified view of (a) in the image.

[0015] like Figure 11 As shown in (b), the filler fiber F located outside the joint of the sealing ring body is visually confirmed to be slender, and the axis of the filler fiber F is oriented in a manner perpendicular to the axis of the sealing ring body (the axis of the filler fiber F is oriented parallel to the flow direction of the molten resin).

[0016] In contrast, Figure 12 In (b) of the diagram, the axis of the filling fiber F cannot be visually confirmed. Figure 11 As in (b) above, it is oriented vertically relative to the axis of the sealing ring body.

[0017] That is, it can be seen that in the filling fibers near the joint of the sealing ring body, the axis of the filling fibers is oriented in a direction perpendicular to the flow direction of the molten resin.

[0018] The aforementioned phenomenon arises from the collision between the resin and the mold's joint end, corresponding to the joint portion of the sealing ring body in the mold, causing disorder in the orientation of the filler fibers. Furthermore, near the joint portion of the sealing ring, because the filler fibers are oriented perpendicular to the flow direction of the molten resin, the curing shrinkage rate of this portion is smaller than that of other portions (locations other than near the joint portion). As a result, the thickness near the joint portion is greater than that of other portions.

[0019] As a result, the thickness near the joint is greater than that in other parts of the sealing ring body, which further deteriorates the flatness of the sealing ring body and leads to a reduction in the sealing performance of the sealing ring.

[0020] Furthermore, if a gate is provided at the position of the mold corresponding to the joint portion of the sealing ring body, and the sealing ring is formed by injection molding resin containing filler fibers from this gate, if a resin accumulation portion as described above is formed, the resin accumulation portion must be removed with high precision after injection molding, which requires more time or materials and incurs costs.

[0021] The present invention was made to solve the above-mentioned technical problems, and its purpose is to provide a sealing ring that, in a sealing ring made of resin incorporating filler fibers, does not require the formation of a resin accumulation portion that is removed after injection molding as in the past, and has good flatness and sealing performance.

[0022] means for solving problems

[0023] To solve the above problems, the sealing ring of the present invention is a sealing ring that seals the annular gap between a housing and a shaft assembled inside the housing. Furthermore, the sealing ring is a sealing ring made of resin with filling fibers that does not form a resin accumulation portion during injection molding. The sealing ring is characterized by comprising: an annular sealing ring body having a joint portion; and a plurality of protrusions formed on the inner circumferential surface of the sealing ring body and protruding radially inward, the protrusions being formed at least near the joint portion.

[0024] Thus, the sealing ring of the present invention has a plurality of tabs formed on the inner circumferential surface of the sealing ring body and protruding radially inward, and the tabs are formed at least near the joint. Therefore, when the sealing ring is injection molded, the molten resin flows into the tab forming part of the mold, and the mold pressure in the mold area corresponding to the joint of the sealing ring body is reduced.

[0025] As mentioned above, compared to locations other than the opening, the curing shrinkage rate tends to be smaller near the joint where the filler orientation is disordered.

[0026] Furthermore, near the joint, the internal pressure of the mold decreases, which tends to increase the curing shrinkage rate. Therefore, near the joint, the decrease in curing shrinkage rate caused by the disorder of filler orientation and the increase in curing shrinkage rate caused by the decrease in internal mold pressure are offset.

[0027] As a result, the curing shrinkage rate near the joint becomes approximately the same as that of other parts of the sealing ring body, and the thickness near the joint becomes approximately uniform with the thickness of other parts of the sealing ring body, which can improve the flatness and sealing performance of the sealing ring.

[0028] In addition, since no resin deposit is formed as in the past, it is not necessary to remove the resin deposit after the sealing ring is injection molded, which can reduce labor time and materials.

[0029] Additionally, it is preferable that the length from the end of the joint to the end of the tab closest to the end of the joint is 0.5 mm or more and 2.5 mm or less.

[0030] When the length dimension from the end of the joint to the end of the tab closest to the end of the joint exceeds 2.5 mm, the length dimension becomes large, and therefore the effect of reducing the internal pressure of the mold caused by the molten resin flowing into the tab forming part of the mold is small.

[0031] On the other hand, even if the length from the end of the joint to the end of the tab closest to the end of the joint is less than 0.5 mm, it is possible to obtain the effect of reducing the pressure inside the mold caused by the molten resin flowing into the tab forming part of the mold. However, when the length is less than 0.5 mm, the shape of the joint becomes complicated and the mold making becomes difficult, so it is not preferred.

[0032] The length of the filling fiber is preferably less than 1000 μm.

[0033] When the length of the filler fiber exceeds 1000 μm, the shrinkage anisotropy during injection molding becomes stronger, which is therefore not preferred. Furthermore, it is preferable that the average length of the filler fiber is approximately 200 μm.

[0034] Furthermore, preferably, the cross-sectional area of ​​the protrusion and the sealing ring body overlapping at the location of the protrusion formed near the joint is larger than the cross-sectional area of ​​the left and right sides of the protrusion that is parallel to the axis of the sealing ring body.

[0035] In this way, since the cross-sectional area parallel to the axis of the overlapping tab and the sealing ring body is larger than the cross-sectional area parallel to the axis of the sealing ring body at the left and right sides of the tab, the internal pressure of the mold in the mold area corresponding to the joint can be reduced.

[0036] Additionally, preferably, at the joint, one end of the sealing ring body is opposite to the other end, and engaging protrusions or engaging recesses are formed at the one end and the other end, wherein the cross-sectional area of ​​the engaging protrusions or engaging recesses parallel to the axis is smaller than the cross-sectional area parallel to the axis of the sealing ring body.

[0037] Thus, even if a locking protrusion or locking recess with a cross-sectional area parallel to the axis smaller than that of the sealing ring body is formed at one end and the other end of the joint, the mold pressure in the mold area corresponding to the joint of the sealing ring body is reduced during the injection molding of the sealing ring because the molten resin flows into the protrusion forming part of the mold.

[0038] Therefore, as described above, compared to locations other than the joint, the curing shrinkage rate tends to be smaller near the joint where the filler orientation is disordered, while near the joint, the mold pressure decreases, and the curing shrinkage rate tends to increase due to this decrease in mold pressure.

[0039] As a result, near the joint, the reduction in curing shrinkage caused by the disorder of filler orientation and the increase in curing shrinkage caused by the reduction in mold pressure are offset, and the thickness near the joint becomes approximately uniform with the thickness at other locations of the sealing ring body, which can improve the flatness and sealing performance of the sealing ring.

[0040] Additionally, preferably, the angle of inclination of the side of the tab relative to the circumferential direction of the sealing ring body is set in the range of 100° or more and 150° or less.

[0041] When the tilt angle of the tab's side is less than 100°, the orientation of the filling fibers within the tab is easily disordered, which is therefore not preferred. Furthermore, when the tilt angle of the tab's side exceeds 150°, the circumferential length of the tab increases, and the curing shrinkage rate also increases in areas other than near the joint, leading to a deterioration in flatness, which is also not preferred.

[0042] Additionally, preferably, the radial thickness of the tab is smaller than the radial thickness of the sealing ring body.

[0043] When the radial thickness of the sealing ring body is smaller than the radial thickness of the tab, the mechanical strength of the sealing ring body decreases, and therefore it is not preferred.

[0044] Alternatively, preferably, the sealing ring body can be installed in an annular groove formed on a shaft that can be inserted into the housing, and during installation, the front ends of the plurality of protrusions can abut against the bottom surface of the annular groove.

[0045] Invention Effects

[0046] According to the present invention, in the sealing ring made of resin incorporating filler fibers, it is not necessary to form the resin accumulation portion that is removed after injection molding as in the past, and a sealing ring with good flatness and sealing performance can be obtained. Attached Figure Description

[0047] Figure 1 This is a perspective view of a sealing ring according to an embodiment of the present invention.

[0048] Figure 2 Observing from other directions Figure 1 A three-dimensional view of the sealing ring.

[0049] Figure 3 (a) in the middle is Figure 1 , Figure 2 Top view of the sealing ring. Figure 3 (b) is a side view taken from the outside of the sealing ring.

[0050] Figure 4 This is a cross-sectional view parallel to the axis of the sealing ring body, showing the sealing ring installed in the annular groove of the shaft according to an embodiment of the present invention.

[0051] Figure 5 (a) is a magnified perspective view showing the joint and the protrusions nearby. Figure 5 (b) in the middle is Figure 5 Section II of (a) in the image.

[0052] Figure 6 (a) is a magnified top view of the joint and the protrusions nearby. Figure 6 (b) is a side view of the joint as seen from the outside of the sealing ring.

[0053] Figure 7 Other forms of the joint are shown. Figure 7 (a) is a magnified top view of the joint and the protrusions nearby. Figure 7 (b) is a side view of the joint as seen from the outside of the sealing ring.

[0054] Figure 8 It is a 3D diagram of the previous sealing ring.

[0055] Figure 9 It is a cross-sectional view parallel to the axis of the sealing ring body, with the shaft equipped with the conventional sealing ring assembled in the housing.

[0056] Figure 10 This is a top view of the traditional sealing ring.

[0057] Figure 11The previous sealing ring is shown. Figure 11 (a) is a cross-sectional view of the sealing ring body, taken at a location other than near the joint of the sealing ring body, perpendicular to the axis of the sealing ring body. Figure 11 (b) in the middle is Figure 11 A magnified view of (a) in the image.

[0058] Figure 12 The previous sealing ring is shown. Figure 12 (a) is a cross-sectional view of the area near the joint of the sealing ring body, perpendicular to the axis of the sealing ring body. Figure 12 (b) in the middle is Figure 12 A magnified view of (a) in the image. Detailed Implementation

[0059] Hereinafter, embodiments of the sealing ring according to the present invention will be described based on the accompanying drawings. In this embodiment, the sealing ring is, for example, assembled between a shaft and a housing that move relative to each other within the hydraulic circuit of an automatic transmission in an automobile, serving to seal the lubricating oil while sliding.

[0060] Figure 1 This is a perspective view of the sealing ring according to an embodiment of the present invention. Figure 2 Observing from other directions Figure 1 A three-dimensional view of the sealing ring. Additionally, Figure 3 (a) in the middle is Figure 1 , Figure 2 Top view of the sealing ring. Figure 3 (b) in the image is a side view taken from the outside of the sealing ring. Additionally, Figure 4 This is a cross-sectional view parallel to the axis of the sealing ring body, showing the sealing ring installed in the annular groove of the shaft according to an embodiment of the present invention.

[0061] Furthermore, the axis of the sealing ring body refers to the line extending vertically from the center C (center of the ring) of the annular sealing ring in the state where the sealing ring is installed in the annular groove of the shaft according to the embodiment of the present invention, relative to the plane containing the first sealing surface of the sealing ring.

[0062] The illustrated sealing ring 1 includes: an annular sealing ring body 1A for sealing the gap between the housing and the shaft, which is formed of a material in which carbon fiber or other filler fibers are incorporated as reinforcing materials, such as polyamide (PA), fluoropolymers (polytetrafluoroethylene (4-fluorinated) (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / ethylene copolymer (ETFE), etc.), liquid crystal polymers (LCP), polyimide (PI), polyetherketone (PEK), polyaryl etherketone (PAEK), polyetherketone etherketone ketone (PEKEKK), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polybenzimidazole (PBI), etc.); and a plurality of tabs 10 formed on the inner circumferential surface of the sealing ring body 1A. The cross-section of the sealing ring body 1A parallel to the axis of the sealing ring body at the position where the tabs 10 are not formed is rectangular.

[0063] Furthermore, the sealing ring 1 is a resin-made sealing ring that does not form the resin accumulation portion shown in Patent Document 1. Additionally, as described above, since the resin in this sealing ring 1 does not contain filler fibers, it exhibits high wear resistance.

[0064] More specifically, such as Figure 4 As shown, a first sealing surface 2 is provided on the oil seal side (sealing surface side) of the sealing ring body 1A. This first sealing surface 2 is in sliding contact with the side wall surface (the side surface of the oil seal side of the annular groove) 21a of the shaft 20, and seals the side wall surface 21a.

[0065] Furthermore, the outer peripheral surface of the sealing ring body 1A is the second sealing surface 5. This second sealing surface 5 contacts the inner peripheral surface 31 of the housing 30 and provides a seal.

[0066] As mentioned above, in Figures 1 to 3 On the inner circumferential surface 7 of the sealing ring 1 shown, a plurality of protrusions 10 (6 in the figure) are provided at predetermined intervals.

[0067] like Figure 3 As shown, each protrusion 10 protrudes radially inward beyond the inner circumferential surface 7, as... Figure 4 As shown, when the sealing ring 1 is installed in the annular groove 21 of the shaft 20, if the sealing ring body 1A and the shaft 20 are offset from each other, the front end 10a of the protrusion 10 abuts against the bottom surface 21b of the annular groove 21.

[0068] Thus, as one of the functions of the tab 10, it has the function of preventing the center C of the sealing ring body 1A from deviating significantly from the center of the shaft 20 when the shaft 20 is assembled inside the housing 30.

[0069] In addition, such as Figures 1 to 3As shown, a joint 15 (separation portion) is formed at a position in the circumference of the sealing ring 1. When installed on the shaft 20, the sealing ring 1 is easily installed in the annular groove 21 of the shaft 20 by expanding the sealing ring 1 in the direction of separating the joint 15.

[0070] The tabs 10 are respectively disposed near both ends of the sealing ring body 1A separated from the joint 15.

[0071] Specifically, the tab 10 is provided at least near the end of the joint 15 of the sealing ring body 1A (at the location where the cross-sectional area changes in the joint 15).

[0072] Therefore, during the injection molding of the sealing ring 1, molten resin containing filler fibers flows into the protrusion forming portion of the mold, reducing the internal pressure of the mold in the mold area corresponding to the joint with the sealing ring body 1A.

[0073] Furthermore, as mentioned above, compared to locations other than the joint area, the curing shrinkage rate tends to be smaller near the joint area where the filler orientation is disordered. Near this joint area, the mold pressure decreases, and due to this decrease in mold pressure, the curing shrinkage rate tends to increase.

[0074] Therefore, near the joint, the reduction in curing shrinkage caused by filler orientation disorder and the increase in curing shrinkage caused by the decrease in mold pressure are offset.

[0075] As a result, the curing shrinkage rate near the joint becomes approximately the same as that of other parts of the sealing ring body, and the thickness near the joint becomes approximately uniform with the thickness of other parts of the sealing ring body, which can improve the flatness and sealing performance of the sealing ring.

[0076] The length of the filler fibers contained in the resin forming the sealing ring 1 is preferably 1000 μm or less. If the length of the filler fibers exceeds 1000 μm, the shrinkage anisotropy during injection molding becomes stronger, and therefore, this is not preferred.

[0077] In addition, the average length of the filling fiber is preferably around 200 μm.

[0078] Furthermore, the filler fiber is not limited to the length mentioned above; any shape and size that can achieve the effect of wear resistance is acceptable. Carbon fiber is exemplified as a filler fiber, but the present invention is not limited to carbon fiber; for example, glass fiber or CNF (cellulose nanofibers) may also be used.

[0079] Next, the structure of the joint 15 and the tab 10 will be described in detail.

[0080] Figure 5Image (a) is an enlarged perspective view showing the joint 15 and the protrusion 10 nearby. Figure 5 (b) in the middle is Figure 5 Section II of (a) in the image. Additionally... Figure 6 (a) is a magnified top view of the joint 15 and the protrusion 10 nearby. Figure 6 (b) is a side view of the joint 15 viewed from the outside of the sealing ring body 1A.

[0081] The joint 15, i.e., the position where one end of the sealing ring body 1A is opposite to the other end, has a locking protrusion or locking recess that can engage with each other. The cross-sectional area of ​​the locking protrusion or locking recess parallel to the axis is smaller than the cross-sectional area parallel to the axis of the sealing ring body 1A.

[0082] Specifically, an inner circumferential sidewall 15a is formed on one end of the sealing ring body 1A, which extends in a wall-like manner along the inner circumferential surface of the sealing ring body 1A.

[0083] Furthermore, a lower section 15b is formed on the radially outer side of the inner circumferential sidewall 15a, extending circumferentially in a stepped manner. An upper recess 15c is formed thereon by forming the lower section 15b.

[0084] On the other hand, an inner circumferential recess 15d is formed on the other end of the sealing ring body 1A, and the inner circumferential recess 15d is formed to engage with the inner circumferential sidewall 15a on the inner circumferential surface of the sealing ring body 1A.

[0085] In addition, an upper section 15e is provided extending radially outward from the inner circumferential recess 15d. The upper section 15e is formed to engage with the lower section 15b and engage with the upper recess 15c.

[0086] In addition, by forming the upper section 15e, a lower section recess 15f is formed below it, and the lower section 15b engages there.

[0087] Thus, in the joint 15, the two ends of the sealing ring body 1A are formed in a stepped shape. Through the interlocking structure, when the joint 15 is closed, the first sealing surface 2, which serves as the sealing surface, is not connected to the non-sealing surface 6, and the second sealing surface 5 is not connected to the non-sealing surface 7, thereby improving the sealing performance.

[0088] In addition, such as Figure 6As shown in (a), as described above, the tab 10 is provided at least near the end of the joint 15 of the sealing ring body 1A (at the location where the cross-sectional area changes in the joint 15). Preferably, the length L1 from the end of the joint 15 to the end of the tab 10 closest to the end of the joint 15 is formed to be 0.5 mm or more and 2.5 mm or less.

[0089] The length L1 from the end of the joint 15 to the nearest tab 10 refers to the length from the two ends of the sealing ring body 1A that are stepped, i.e., the position where the cross-sectional shape changes in the joint 15 of the sealing ring body 1A (the end of the joint), to the nearest tab 10.

[0090] Furthermore, when the length dimension from the end of the joint to the end of the tab closest to the end of the joint exceeds 2.5 mm, the length dimension becomes large, and therefore the effect of reducing the internal pressure of the mold caused by the molten resin flowing into the tab forming part of the mold is small.

[0091] On the other hand, even if the length dimension from the end of the joint to the end of the tab closest to the end of the joint is less than 0.5 mm, it is possible to obtain the effect of reducing the pressure inside the mold caused by the molten resin flowing into the tab forming part of the mold. However, when the length dimension is less than 0.5 mm, the shape of the joint becomes complicated and the mold making becomes difficult, so it is not preferred.

[0092] In addition, the inclination angle of the side of the protrusion relative to the circumferential direction of the sealing ring body is set in the range of 100° or more and 150° or less.

[0093] When the inclination angle of the tab's side is less than 100°, the orientation of the filling fibers within the tab is easily disordered, therefore, this is not preferred. Furthermore, when the inclination angle of the tab's side exceeds 150°, the circumferential length of the tab increases, and the curing shrinkage rate also increases in areas other than near the joint, leading to a deterioration in flatness; therefore, this is also not preferred.

[0094] Moreover, such as Figure 6 As shown in (a), the radial thickness dimension L2 of the tab 10 is formed to be smaller than the radial thickness dimension L3 of the sealing ring body 1A.

[0095] When the radial thickness L3 of the sealing ring body is smaller than the radial thickness L2 of the tab, the radial thickness of the sealing surface 2 of the sealing ring body 1A becomes smaller, and the sealing performance is reduced. Therefore, this is not preferred.

[0096] Therefore, from the viewpoint of the sealing performance of the sealing ring body 1A, it is preferable that the radial thickness dimension L3 of the sealing ring body 1A is formed to be larger than the radial thickness dimension L2 of the tab 10.

[0097] In addition, such as Figure 5 As shown in (b), the cross-sectional area S1 of the tab 10 overlapping with the sealing ring body 1A and parallel to the axis is larger than the cross-sectional area S2 of the tab 10 at the left and right sides (positions where no tab is formed) that is parallel to the axis of the sealing ring body 1A.

[0098] Therefore, during the injection molding of the sealing ring 1, molten resin containing filler fibers flows into the protrusion forming part of the mold, and the internal pressure of the mold in the area of ​​the mold corresponding to the joint is reduced.

[0099] The sealing ring 1 thus formed is obtained by injection molding molten resin containing filler fibers into a mold (not shown).

[0100] In the mold, the resin inlet is formed at a position corresponding to the portion of the mold opposite to the joint 15 of the sealing ring 1. In the molded sealing ring 1, as... Figure 2 As shown, a gate mark 17 is formed on the inner circumferential surface 7 of the opposite portion of the joint 15 on the sealing ring 1.

[0101] Molten resin ejected from the injection nozzle (not shown) flows into the mold from the gate of the mold, separates on the left and right sides, and flows toward the forming part of the joint 15 by a predetermined mold internal pressure.

[0102] In addition, as described above, the molten resin flowing from the gate to the left and right sides also flows into the protrusion forming part of the mold corresponding to the protrusion 10.

[0103] Furthermore, a tab forming portion is provided near the joint forming portion of the mold corresponding to the joint portion 15. Therefore, the internal pressure of the mold is reduced by the tab forming portion, which is the molten resin passing through the tab forming portion, i.e. the molten resin near the opening forming portion.

[0104] As mentioned above, compared to locations other than the joint area, the curing shrinkage rate tends to be smaller near the joint area where the filler orientation is disordered.

[0105] Furthermore, since the mold pressure of the molten resin near the joint forming part is reduced by the tab forming part, there is a tendency for the curing shrinkage rate to increase due to the reduction in mold pressure.

[0106] Therefore, near the joint, the reduction in curing shrinkage caused by the disorder of filler orientation and the increase in curing shrinkage caused by the decrease in mold pressure are offset.

[0107] As a result, the thickness near the joint becomes roughly uniform with the thickness of other parts of the sealing ring body, which improves the flatness and sealing performance of the sealing ring.

[0108] In addition, the resin accumulation zone is not formed as in the past. Therefore, after the sealing ring is injection molded, it is not necessary to remove the resin accumulation zone, which can reduce labor time and materials.

[0109] In addition, by positioning the gate at the opposite part of the joint, the amount of resin flowing to the left and right sides of the sealing ring body 1A becomes the same, and the pressure inside the mold of the molten resin is reduced, thus preventing the generation of burrs and the like.

[0110] Furthermore, in the above embodiments, such as Figure 6 As shown, in the joint 15, the two ends of the sealing ring body 1A are formed in a stepped shape to form a mutually engaging structure, but in this invention, it is not limited to this structure.

[0111] For example, it can also be like Figure 7 Top view of joint 15 in (a), Figure 7 The structure is configured as shown in the side view of (b). Specifically, an inner circumferential sidewall 15g is formed on the inner circumferential surface of the sealing ring, extending circumferentially in a wall-like manner at one end of the sealing ring body 1A. Furthermore, a step-shaped engaging protrusion 15h is formed radially outward of this inner circumferential sidewall 15g, extending circumferentially in a step-like manner. By forming the engaging protrusion 15h, an upper recess 15i (engaging recess) and a lower recess 15j (engaging recess) are formed above and below it, respectively.

[0112] On the other hand, an inner circumferential recess 15k is formed on the other end of the sealing ring body 1A, and the inner circumferential recess 15k is formed to engage with the inner circumferential sidewall 15g on the inner circumferential surface of the sealing ring.

[0113] Additionally, at a position radially outward from the inner peripheral recess 15k, an upper protrusion 15m (engaging protrusion) and a lower protrusion 15n (engaging protrusion) are provided, capable of engaging with the engaging protrusion 15h and engaging with the upper recess 15i and the lower recess 15j, respectively.

[0114] In addition, by forming the upper protrusion 15m and the lower protrusion 15n, an intermediate recess 15p (engaging recess) is formed therebetween, and the engaging protrusion 15h engages here.

[0115] Thus, in the joint 15, it is also possible to form a structure in which the two ends of the sealing ring body 1A are formed into opposing concave and convex shapes and engage with each other.

[0116] In this case, with the joint 15 closed, the first sealing surface 2, which serves as the sealing surface, is not in communication with the non-sealing surface 6, and the second sealing surface 5 is not in communication with the non-sealing surface 7, thus improving the sealing performance.

[0117] Furthermore, in the above embodiments, such as Figure 3 The diagram shows a case where six tabs 10 are provided in the sealing ring 1, but in this invention, the number of tabs 10 is not particularly limited to six.

[0118] Furthermore, in the above embodiments, the case of using a resin injection-molded sealing ring containing filler fibers has been described, but the present invention is not limited thereto and can also be applied to the case of using a resin injection-molded sealing ring without filler fibers.

[0119] (Example 1)

[0120] The following sealing ring was manufactured by injection molding.

[0121] The sealing ring has Figure 6 The stepped joint shown is made of polyetheretherketone (PEEK) and has an outer diameter of [missing information]. Inner diameter is

[0122] Furthermore, the filling fibers contained in the resin forming the sealing ring have a length dimension of less than 1000 μm and an average length dimension of 200 μm. The number of tabs 10 is 6. The length dimension L1 from the end of the joint to the end of the tab closest to the end of the joint is 1 mm. The radial thickness dimension L2 of the tab is 0.5 mm. The radial thickness dimension L3 of the sealing ring body is 2 mm. The tilt angle θ of the tab side is 120 degrees.

[0123] Then, using a micrometer, the maximum and minimum axial thickness of the sealing ring body at 10 locations were measured, and the difference was calculated as the flatness.

[0124] The result was a flatness of 0.014 mm.

[0125] (Example 2)

[0126] Except that the length L1 from the end of the joint to the end of the tab closest to the end of the joint is set to 0.5 mm, the sealing ring was manufactured by injection molding under the same conditions as in Embodiment 1 above.

[0127] Then, using a micrometer, the maximum and minimum axial thickness of the sealing ring body at 10 locations were measured, and the difference was calculated as the flatness.

[0128] The result was a flatness of 0.01 mm.

[0129] (Example 3)

[0130] Except that the length L1 from the end of the joint to the end of the tab closest to the end of the joint is set to 1.5 mm, the sealing ring was manufactured by injection molding under the same conditions as in Embodiment 1 above.

[0131] Then, using a micrometer, the maximum and minimum axial thickness of the sealing ring body at 10 locations were measured, and the difference was calculated as the flatness.

[0132] The result was a flatness of 0.017 mm.

[0133] (Example 4)

[0134] Except that the length L1 from the end of the joint to the end of the tab closest to the end of the joint is set to 2.5 mm, the sealing ring was manufactured by injection molding under the same conditions as in Embodiment 1 above.

[0135] Then, using a micrometer, the maximum and minimum axial thickness of the sealing ring body at 10 locations were measured, and the difference was calculated as the flatness.

[0136] The result was a flatness of 0.019 mm.

[0137] (Example 5)

[0138] As in Example 5, the length L1 from the end of the joint to the end of the tab closest to the end of the joint is set to 0.3 mm. Otherwise, under the same conditions as in Example 1, the production of the sealing ring was attempted. However, since the length from the joint end of the mold to the end of the tab closest to the joint end is short, the joint shape of the mold becomes complicated, so the production of the mold was abandoned.

[0139] (Comparative Example 1)

[0140] As a comparative example 1, a sealing ring identical to that of Example 1 was fabricated, except that the tabs in Example 1 were not formed. Then, in the same manner as in Example 1, the maximum and minimum values ​​of the axial thickness of the sealing ring body at 10 locations were measured, and the difference was determined as the flatness.

[0141] The result was a flatness of 0.024 mm.

[0142] (Comparative Example 2)

[0143] Except that the length L1 from the end of the joint to the end of the tab closest to the end of the joint is set to 3 mm, the sealing ring was manufactured by injection molding under the same conditions as in Embodiment 1 above.

[0144] Then, using a micrometer, the maximum and minimum axial thickness of the sealing ring body at 10 locations were measured, and the difference was calculated as the flatness.

[0145] The result was a flatness of 0.024 mm.

[0146] As described above, flatness was not measured in Example 5, but it can be inferred that even if the length dimension from the end of the joint to the end of the tab closest to the end of the joint is short, as in Example 5, the effect of reducing the pressure inside the mold can be obtained by the flow of molten resin into the tab forming part of the mold.

[0147] However, as in Embodiment 5, if the length from the end of the joint to the end of the tab closest to the end of the joint becomes too short, the shape of the joint becomes complicated and the mold becomes difficult to manufacture. Therefore, it is not preferred from the point of view of mold manufacturing.

[0148] Furthermore, when comparing the sealing rings of Examples 1 to 4, where the tabs are formed at least near the joint, with the sealing rings of Comparative Examples 1 and 2, the flatness of Examples 1 to 4 is excellent. Moreover, due to the excellent flatness, it can be said that the sealing performance is also excellent.

[0149] Therefore, it was confirmed that by forming tabs at least near the joint, flatness and sealing performance were improved.

[0150] Explanation of reference numerals in the attached figures

[0151] 1. Sealing ring

[0152] 1A Sealing Ring Body

[0153] 2 First sealing surface

[0154] 5 Second sealing surface

[0155] 6 Non-sealed surfaces

[0156] 7. Inner circumferential surface

[0157] 10 protrusions

[0158] 15 Joint

[0159] 20-axis

[0160] 21 Ring-shaped groove

[0161] 21a Side (Oil Seal Side)

[0162] 22 gap

[0163] 30. Housing

[0164] 31 Inner circumferential surface of the shell

Claims

1. A sealing ring for sealing an annular gap between a housing and a shaft assembled inside the housing, wherein the sealing ring is made of resin with filler fibers and does not form a resin accumulation portion during injection molding, characterized in that, have: The annular sealing ring body has a joint portion and a gate mark formed on the inner circumferential surface of the opposite portion of the joint portion, which serves as a gate mark for the molten resin containing filling fibers to flow into. as well as Multiple protrusions are formed on the inner circumferential surface of the sealing ring body and protrude radially inward. The tab is formed at least near the joint, and its length from the point where the cross-sectional shape changes in the joint (i.e., the end of the joint) to the end of the tab closest to the end of the joint is 0.5 mm or more and 2.5 mm or less. Furthermore, the cross-sectional area of ​​the sealing ring body remains unchanged from the end of the joint to the end of the protrusion closest to the end of the joint. The filler fibers, excluding those near the joint, have their axes oriented perpendicularly to the axis of the sealing ring body. The filling fibers near the joint are oriented in a disordered manner relative to the orientation of the filling fibers outside the vicinity of the joint.

2. The sealing ring according to claim 1, characterized in that, The length of the filling fiber is less than 1000 μm.

3. The sealing ring according to claim 1, characterized in that, At the location of the protrusion formed near the joint, the cross-sectional area of ​​the protrusion and the sealing ring body overlapping, parallel to the axis, is larger than the cross-sectional area of ​​the left and right sides of the protrusion parallel to the axis of the sealing ring body.

4. The sealing ring according to claim 1, characterized in that, At the joint, one end of the sealing ring body is opposite to the other end. Furthermore, engaging protrusions or engaging recesses are formed at one end and the other end, and the cross-sectional area of ​​the engaging protrusion or the engaging recess parallel to the axis is smaller than the cross-sectional area parallel to the axis of the sealing ring body other than the joint.

5. The sealing ring according to claim 1, characterized in that, The angle of inclination of the side of the protrusion relative to the inner circumferential surface of the sealing ring body is set in the range of 100° or more and 150° or less.

6. The sealing ring according to claim 1, characterized in that, The radial thickness of the tab is smaller than the radial thickness of the sealing ring body.

7. A sealing ring mounting structure, which is a sealing ring mounting structure according to any one of claims 1 to 6, wherein the sealing ring seals the annular gap between a housing and a shaft assembled inside the housing, characterized in that, The sealing ring body is installed in an annular groove, which is formed on a shaft that can be inserted into the housing. When the sealing ring is installed, if the sealing ring body and the shaft are offset from the center, the front end of the protrusion formed on the inner circumferential surface of the sealing ring body and protruding radially inward abuts against the bottom surface of the annular groove.

Images