JP2007078041A - Resinous seal ring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resinous seal ring which can generate leakage of oil and reduce a dragging torque caused between the seal ring and a mounted shaft much more than before. <P>SOLUTION: The resinous seal ring is manufactured as follows. Cut-out portions 13 are formed on the inside-diameter sides of both surfaces of the seal ring 11 so as to form a polygonal or projected cross section. Then, the cut-out portions 13 are continuously connected in the ring shape over the whole periphery of the seal ring by connecting abutment portions having a composite step-cut shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a seal ring, and more particularly to a seal ring in which a drag torque of the seal ring is reduced.

  Generally, in automatic transmissions (AT) and continuously variable transmissions (CVT) that are attached to automobiles such as torque converters and hydraulic clutches, an oil seal ring for sealing hydraulic oil is attached to the main points as shown in FIG. It has been. Such an oil seal ring is rotatable between the cylinder 6 and the shaft 7 and is required to have sufficient oil sealability.

  Conventionally, cast oil seal rings and fluororesin seal rings have been used for such oil seal rings, but now they are manufactured by injection molding to improve wear resistance, oil sealability, and cost. Synthetic resin seal rings having mating portions facing each other are often used. As the synthetic resin used in this way, for example, a resin composition containing polyether ether ketone is used.

  Examples of the mating portion of the seal ring 1 include a straight cut shape, a step shape, a composite step cut shape, and the like. Especially, as a mating portion capable of reducing oil leakage, a lip 4 as shown in FIG. A compound step cut shape having a pocket 5 is known (for example, described in paragraph [0003] of Patent Document 1).

  Further, the seal ring may lose a force to be transmitted due to friction when the side surface comes into contact with the shaft or the like. As a seal ring for reducing drag torque due to friction that causes this loss, a seal ring (described in Patent Document 2) in which a lubrication groove 3 is intermittently provided on the inner side surface as shown in FIG. Among the side surfaces on the inner diameter side as shown in FIG. 4, there is a seal ring (described in Patent Document 3) in which the lubrication groove 3 is made continuous except for the vicinity of the abutment portion around the butting surface 2.

  Further, in order to reduce the drag torque by reducing the contact area of the side surface, a seal ring as shown in FIG. 5 in which the lubrication groove 3 is further expanded in the radial direction is further studied rather than the seal ring of FIG. .

JP-A-8-75007 Japanese Utility Model Publication No. 5-61566 JP-A-9-217837

  However, in the seal ring 1 provided with the lubrication grooves 3 as shown in FIGS. 3 and 4, the drag torque is not sufficiently reduced. Further, in the seal ring in which the lubrication groove 3 is expanded in the radial direction as shown in FIG. 5, it is usually as shown in FIG. 5B, but when the cylinder 6 and the shaft 7 are eccentric. As shown in FIG. 5C, the oil may leak from the enlarged radial direction side of the lubricating groove 3.

  Further, when the accuracy of the mating groove of the shaft into which the seal ring is fitted is deteriorated, and the groove wall in contact with the side surface of the seal ring is inclined, that is, when the squareness is increased, any one of FIGS. Even in the seal ring, the pillar portion 8 without the lubrication groove 3 on the inner diameter side and the corner portions before and after the joint portion without the lubrication groove 3 are obstructing, and the clearance between the seal ring 1 and the shaft 7 is increased. There was a problem that oil leaked easily.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resin seal ring with less oil leakage and reduced drag torque between the shaft and the shaft.

  The present invention provides a composite step cut shape without interrupting the burial portion formed so that the cross-sectional shape is polygonal or convex on the inner diameter surface side of the both side surface portions of the seal ring at the column portion or the mating portion. The above-mentioned problems have been solved by connecting the sealing openings that are connected to each other over the entire circumference of the seal ring connected in a ring shape.

  That is, the drag torque is reduced by reducing the area where the side surface of the seal ring contacts, and the gap between the shaft and the seal ring is reduced because the inner diameter side is closer to the radial side, Oil leak is less likely to occur. In addition, a composite step-cut shape having a butting surface, a lip and a pocket at one abutting portion and a butting surface, a pocket and a lip formed so as to be complementarily assembled with each other at the other abutting portion; By doing so, it is possible to reduce oil leakage at the abutment portion.

  Further, by setting the thickness between the wall on the inner diameter side of the pocket and the Nusumi portion to be 0.1 mm or more, more preferably 0.3 mm or more, the strength of the contacting side surface can be maintained. By setting it to 8 mm or less, more preferably 0.5 mm or less, the corner portion on the inner diameter side of the side surface is in contact with the wall surface such as the shaft, and the above gap is suppressed from increasing, and oil leakage is similarly reduced. be able to.

  Furthermore, by rounding the corners, the above gap can be reduced, and oil leakage can be reduced in the same manner.

  Further, by using a polyether ether ketone resin as the resin for producing the seal ring, high wear resistance and oil sealability can be obtained.

  If the seal ring concerning this invention is used, drag torque can be made small by the area which a seal ring side surface contacts reduces, and the energy loss produced between a shaft can be made small. Moreover, since the corners on the inner diameter side are less likely to get in the way, oil leakage is less likely to occur.

  The present invention will be described in detail below with reference to FIGS. The seal rings 11 and 11 ′ according to the present invention are resin seal rings having ring-shaped portions having mutually facing mating portions and connecting the mating portions to each other. As shown in FIG. 1 (a) and FIG. 2 (a), the urging parts 13 and 13 'are formed over the entire circumference.

  As shown in the cross-sectional views of FIG. 1B and FIG. 2B, the side portions of the seal rings 11 and 11 ′ are reduced by forming the above-mentioned nuisance portions 13 and 13 ′, so Since the contact area is reduced, friction is reduced and drag torque can be reduced. Even when the accuracy of the shaft 22 is deteriorated and the squareness is increased, the corner portion 17 that contacts the wall surface of the shaft 22 is formed in the radial portions because the portions 17 and 13 ′ have no flesh. The gap generated between the shaft 22 and the seal ring 11 is reduced, and the possibility of oil leakage can be reduced.

  The cross-sectional shape of the above-mentioned Nusumi portions 13 and 13 ′ may be a convex shape by forming a lubricating groove having a corner 18 from the side as shown in FIG. 1 (b) and FIG. 1 (c). 2 (b) and (c) may be chamfered to have a polygonal shape (hereinafter, the nosumi parts 13 and 13 'are abbreviated as "nosumi part 13"). The seal rings 11 and 11 'are abbreviated as "seal ring 11"). Among these, in particular, when the lubrication groove is engraved as shown in FIG. 1, when taking out from the mold by injection molding, it can be ejected from the mold by pressing the side portion of the Nusumi portion 13 and easy to take out. Therefore, it is preferable.

  The seal ring according to the present invention has an abutment portion that is connected to form a circumference, and this abutment portion is not only the flat abutting surface 12 but is shown in FIGS. As described in (c), it is necessary to have a composite step-cut shape in which the respective surfaces are combined by the lip 14 protruding from each abutting surface 12 and the pocket 15 provided with a recess. As a result, when the abutment portions are combined, a composite structure as shown in FIG. 1D is obtained, and oil leakage from the abutment portion is reduced.

  In the case where the pocket 15 is provided in the above-mentioned joint portion, the surface on the radial direction side of the seal ring 11 is missing. Further, the surface on the central direction side of the seal ring 11 is missing due to the Nusumi portion 13. Accordingly, the portion of the seal ring 11 where the pocket 15 is formed is scraped from both the radial direction and the central direction, and the side surface portion of the seal ring 11 is thin.

  The thickness T of the wall 16 formed on the side surface of the ring between the inner diameter side wall of the pocket 15 and the outer diameter side end portion of the Nusumi portion 13 is when the thickness of the seal ring 11 is 1 mm to 3 mm. , At least 0.1 mm or more is preferable, and 0.3 mm or more is preferable. If it is less than 0.1 mm, it is too thin when contacting the wall surface of the shaft 22, and the sealing surface is small and oil leakage increases. In addition, unexpected deformation may occur. On the other hand, it is preferably 0.8 mm or less, and more preferably 0.5 mm or less. This is because the radial thickness of the seal ring is generally about several millimeters, and even if the pockets 15 and the pussies 13 are too small, the effect of the present invention cannot be sufficiently obtained.

  It is preferable that the corner portion 17 between the above-mentioned Nusumi portion 13 and the wall 16 formed on the side surface of the ring is rounded rather than being a corner. The curvature radius is preferably 0.1 mm or more and 0.5 mm or less when the width of the seal ring 11 is 1 mm to 3 mm. Since the corner portion 17 is chamfered, the gap generated when contacting the shaft 22 having a large squareness is further reduced. Here, if the radius of curvature is less than 0.1 mm, the effect can hardly be exhibited, and it is difficult to exceed 0.5 mm compared to the overall size of the seal ring 11.

  A chamfered portion or a rounded chamfered portion is provided at the corner 31 of the tip end portion of the lip 14 of the above-mentioned joint portion or the boundary portion 32 on the outer diameter side of the pocket 15, or the corner 33 of the pocket 15 is not a right angle. If this is the case, local contact that occurs when fitting these joints is avoided or reduced, so that it is possible to make the mutual joints difficult to break, and more preferable. . When the corner 33 has a rounded shape, the corner 31 of the corresponding lip 14 needs to have a shape that can be combined correspondingly.

Further, when the lip 14 and the pocket 15 are combined with each other, a gap g ₁ is provided between the lip 14 and the inner diameter side surface of the pocket 15 as shown in FIG. 1 (e). It is more preferable that the gap g ₂ is provided between the lips 14 as described, because the dimensional error of the seal ring 11 can be absorbed and the lip 14 can be prevented from protruding in the radial direction. In addition, since an inconvenience may be caused if it is too large, the gap g ₁ is preferably 0.03 mm or less, and the gap g ₂ is preferably 0.01 mm or less at the maximum.

  The resin seal ring according to the present invention is manufactured from a general resin composition that can be used for a seal ring, which is mainly composed of a heat-resistant resin, and is composed of a solid lubricant such as a reinforcing fiber, a fluorine-based resin, or a filler. can do. Among these, it is particularly preferable that the heat resistant resin is a polyether ether ketone resin composition which is a polyether ether ketone. By using the polyether ether ketone resin composition, high wear resistance and oil sealability can be realized.

  The resin seal ring according to the present invention can be manufactured by a known method using injection molding.

  The resin seal ring according to the present invention can be suitably used for, for example, an oil seal ring for an automatic transmission or a continuously variable transmission.

  About the resin-made seal ring concerning this invention, it shows more concretely using an Example.

[Oil leak test]
(Example)
The material shown in FIG. 1 is formed using a material (NTN Precision Resin Co., Ltd .: BEAREE PK5301) containing a polyether ether ketone resin as a main material and carbon fiber and a tetrafluoroethylene resin as a filler. 50 mm in diameter, 2.0 mm in ring width, 1.8 mm in the radial thickness of the ring, 1 mm in the radial direction of the groove in the radius portion, and 0.3 mm in the depth in the ring width direction of the groove in the radius portion Yes, the width T is 0.4 mm, the lip length is 2.5 mm, the pocket radial depth is 1.2 mm, and the corners of the Numi portion and the ring side surface portion have a radius of curvature of 0.3 mm. The seal ring which has a rounded chamfered portion and has a mating portion of a composite step cut shape was injection molded into a form in which the mating portion was widened as shown in FIG. It should be noted that the gap _{g 1} is set to 0.02mm, _{g 2} was 0.005mm. Next, using a jig composed of a cylinder and a ring gauge, an injection-molded seal ring is attached between them and forcedly deformed. The jig is attached to the jig and placed in an electric furnace at 200 ° C. for 2 hours. Was heat-fixed.

  The seal ring thus obtained was mounted between a cylinder and a shaft made of S45C, using an automatic transmission oil for automobiles (manufactured by Showa Shell Sekiyu KK: Gelco ATF). Oil-sealed at 5 MPa. The amount of oil leakage when the shaft was rotated at 4000 rpm was measured with a graduated cylinder over 30 to 120 ° C. The result is shown in the graph of FIG.

(Comparative Example 1)
Compared with the embodiment, the embodiment has the shape of FIG. 3 except that it has a pillar portion 8 having a width of 3 mm for every 6 mm in the circumferential direction, and there is no Nusumi portion over 5 mm before and after the mating portion. Using the same polyether ether ketone seal ring, the same test as in the example was performed. The result is shown in the graph of FIG.

(Comparative Example 2)
A test similar to Comparative Example 1 was performed using a polyether ether ketone seal ring similar to Comparative Example 1 except that it has the shape of FIG. The result is shown in the graph of FIG.

(result)
In the seal ring of the embodiment according to the present invention, the fluctuation of the oil leak amount due to the temperature change was small and stable. On the other hand, in the seal rings of Comparative Examples 1 and 2, the amount of oil leak increased with temperature, and increased about twice as much at 60 ° C and about three times at 100 ° C as compared to the amount at 30 ° C. .

[Rotational torque test]
Using the resin seal rings of the above Examples, Comparative Examples 1 and 2, at a temperature of 80 ° C., using the same shaft, shaft and oil as those used in the oil leak test, at a rotational speed of 4000 rpm. The rotational torque at the time of rotation was measured with a rotary transformer type torque converter (manufactured by Kyowa Denki Co., Ltd .: TPM-1KMCB) at hydraulic pressures of 0.4 MPa, 0.8 MPa, and 1.2 MPa. The result is shown in the graph of FIG.

(result)
The seal ring of the example according to the present invention showed lower rotational torque than Comparative Example 1 and Comparative Example 2 at any hydraulic pressure.

(A) Side view showing an example of a resin seal ring according to the present invention, (b) AA sectional view of (a), (c) Perspective view of the vicinity of the mating portion of (a), (d) ( The perspective view at the time of approaching the joint part of c), (e) The enlarged view of the joint part of (a), The outer surface figure from the radial direction of the joint part of (f) (a) (A) Side view showing another example of the resin seal ring according to the present invention, (b) AA sectional view of (a), (c) Perspective view of the vicinity of the mating portion of (a) (A) Side view of a seal ring provided with a lubricating groove in a part of the side surface according to Comparative Example 1, (b) CC sectional view of (a), (c) Perspective view of the vicinity of the mating portion of (a) Figure (A) A side view of a seal ring provided with a lubricating groove on the side surface other than the vicinity of the butting surface according to Comparative Example 2, (b) DD sectional view of (a), (c) In the vicinity of the mating portion of (a) Perspective view 3A is a side view of a seal ring in which the lubricating groove of FIG. 3 is expanded in the radial direction, FIG. 3B is a cross-sectional view taken along line EE of FIG. 3A, and FIG. ) Perspective view of the vicinity of the joint of (a) The graph which shows the amount of oil leaks in an Example The graph which shows the rotational torque with respect to the hydraulic pressure in an Example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seal ring 2 Butting surface 3 Lubricating groove 4 Lip 5 Pocket 6 Cylinder 7 Axis 8 Column 11, 11 'Sealing ring 12 Butting surface 13, 13' Nusumi 14 Lip 15 Pocket 16 Wall 17 Corner 18 Corner 21 Cylinder 22 Axis 31 corner 32 boundary 33 corner g ₁ , g ₂ gap

Claims (5)

A resin seal ring that has an abutment portion facing each other and can be formed using injection molding that forms a ring by connecting the abutment portions to each other,
The one mating portion has a butt surface on the inner diameter surface side of the resin seal ring, and has a lip projecting from the butt surface and a receding pocket on the outer diameter surface side. The portion has a butting surface, a lip and a pocket of the one abutment portion, and a butting surface, a pocket and a lip formed so as to be complementarily assembled, so that the cross-sectional shape is polygonal or convex. A resin seal ring characterized in that the puss formed on the inner diameter side of both side surfaces extends over the entire circumference.   The seal ring has a radial thickness of 1 mm or more and 3 mm or less, and a wall thickness formed on the ring side surface between the inner wall of the pocket and the Nusumi portion is 0.1 mm or more and 0.8 mm or less. The resin seal ring according to claim 1, wherein   The resin seal ring according to claim 2, wherein the wall thickness is 0.3 mm or more and 0.5 mm or less.   The seal ring has a radial thickness of 1 mm or more and 3 mm or less, a width of 1 mm or more and 3 mm or less, and a corner radius between the Nusumi portion and the ring side surface portion with a radius of curvature of 0.1 mm or more, 0. The resin seal ring according to any one of claims 1 to 3, wherein the rounded chamfer is 5 mm or less.   The resin seal ring according to any one of claims 1 to 4, wherein the resin is a polyetheretherketone resin composition.

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