JP2016014469A - Sealing device - Google Patents

Abstract

In a sealing device including a combination of a seal lip and a seal flange that are slidably in contact with each other, occurrence of static leakage is suppressed.
A stationary leakage suppression structure is provided between an axial end surface of a seal lip and a seal flange. The static leakage suppression structure is provided with a satin-finished portion in one or both of a region of the seal flange that slidably contacts the seal lip and a region of the seal lip that slidably contacts the seal flange. In addition, the static leak suppression structure is a structure in which a matte finish portion is provided on the inner surface of the screw groove, or a cross-sectional shape of the screw groove is an irregular cross section other than a triangle.
[Selection] Figure 5

Description

  The present invention relates to a sealing device according to a sealing technique. The sealing device of the present invention is used, for example, as an oil seal for rotation in the field of automobiles or general-purpose machines.

  Conventionally, as shown in FIG. 9A, the seal lip 102 mounted on the non-rotating housing 51 side is slidably in contact with the axial end surface 103a of the seal flange 103 on the rotating shaft 61 side. An apparatus 101 is known. As shown in FIG. 9B, the axial end surface 103a of the seal flange 103 is provided with a thread groove 104 that exerts a fluid pumping action by centrifugal force when the rotating shaft 61 rotates, and this thread groove 104 is provided. The seal lip 102 is slidably in contact with the axial end surface 103a.

  In the sealing device 101, when the rotary shaft 61 rotates, the seal flange 103 that rotates together with the rotary shaft 61 exhibits a fluid swinging action by centrifugal force, and the thread groove 104 exhibits a fluid pumping action by centrifugal force. It is possible to prevent the sealing fluid from passing through the contact portion between the seal lip 102 and the seal flange 103 and leaking to the outside B.

Japanese Utility Model Publication No. 3-57563 JP-A-2-113173

  However, the conventional sealing device 101 is required to be further improved in terms of the following points.

  That is, in the sealing device 101, as described above, when the rotary shaft 61 rotates, the seal flange 103 that rotates together with the rotary shaft 61 exhibits a fluid swinging action by centrifugal force, and the thread groove 104 exhibits a fluid pumping action by centrifugal force. Therefore, it is possible to suppress leakage of the sealing fluid inside the machine inside A to the machine outside B. However, when the rotation of the rotating shaft 61 stops, the centrifugal force disappears and both the above actions disappear. There is a possibility that the fluid passes along the screw groove 104 and passes through the contact portion and leaks to the outside B (so-called stationary leak may occur).

  In view of the above, the present invention suppresses leakage at rest (stationary leakage) while maintaining sealing performance at the time of rotation in a sealing device including a combination of a seal lip and a seal flange that are slidably in contact with each other. It is an object of the present invention to provide a sealing device that can be used.

  In order to achieve the above object, the present invention employs the following means.

That is, the sealing device of the present invention includes a sealing device having a structure in which a seal lip mounted on a non-rotating housing side is slidably in contact with an axial end surface of a seal flange on the rotating shaft side. A stationary leakage suppression structure is provided between the flange and the axial end surface of the flange.
The static leakage suppression structure is provided with a satin-finished portion in one or both of a region of the seal flange that slidably contacts the seal lip and a region of the seal lip that slidably contacts the seal flange.

  According to this configuration, when the rotating shaft is rotating, a fluid flow is generated toward the outer diameter side through the valley portion of the matte processing portion by the action of the centrifugal force generated with the rotation. Therefore, since the satin-finished part exhibits fluid pumping action by centrifugal force instead of the thread groove, it is possible to suppress the sealing fluid from leaking to the outside of the machine through the contact part of the seal lip and the seal flange. The When the rotating shaft is stationary, the seal lip elastically contacts the seal flange, so that the clearance between the contact portions (the gap between the seal lip and the seal flange in the sliding region, which is due to the valley of the matte finish portion). (Including space), fluid movement at the contact portion is suppressed. Therefore, it is possible to suppress the occurrence of stationary leakage.

Moreover, when the thread groove which exhibits a fluid pumping action at the time of rotation is provided in the axial direction end surface of a seal flange, the stationary leak suppression structure provides the matte processing part in the inner surface of a screw groove.
And, since the surface area of the inner surface of the thread groove is increased as compared with the case where the matte processing part is not provided when the matte processing part is provided on the inner surface of the thread groove in this way, the surface tension of the sealing fluid is easily generated. It becomes difficult for the sealing fluid to flow in the thread groove. Therefore, it is possible to suppress the occurrence of static leakage as described above.

Moreover, when the thread groove which exhibits a fluid pumping effect at the time of rotation is provided in the axial direction end surface of a seal flange, the static leak suppression structure makes the cross-sectional shape of a thread groove into a different cross section other than a triangle.
If the cross-sectional shape of the screw groove is an irregular cross-section other than a triangle in this way, the surface area of the inner surface of the screw groove increases as compared with the case where the cross-sectional shape of the screw groove is a cross-sectional triangle. Is likely to occur, and the sealing fluid is less likely to flow through the thread groove. Therefore, it is possible to suppress the occurrence of static leakage as described above.

  In the present invention, in a sealing device including a combination of a seal lip and a seal flange that are slidably in contact with each other, it is possible to suppress the occurrence of stationary leakage, and not only when the rotating shaft is rotating, but also stationary. The leakage of the sealing fluid can be suppressed even during the operation.

Sectional drawing of the principal part of the sealing device which concerns on 1st Example of this invention. Sectional drawing of the principal part of the sealing device which concerns on 2nd Example of this invention. Sectional drawing of the principal part of the sealing device which concerns on 3rd Example of this invention. Explanatory drawing of the thread groove provided in the sealing device (A) is an enlarged cross-sectional view of the thread groove, and (B) is an enlarged cross-sectional view of a state in which a seal lip is combined with the thread groove. It is a figure which shows the thread groove with which the sealing device which concerns on a comparative example is equipped, Comprising: (A) is sectional drawing of the thread groove, (B) is sectional drawing of the state which combined the seal lip with respect to the thread groove It is a figure which shows the thread groove with which the sealing device which concerns on 4th Example of this invention is equipped, (A) is sectional drawing of the thread groove, (B) is the state which combined the seal lip with the thread groove. Cross section It is a figure which shows the thread groove with which the sealing device based on 5th Example of this invention is equipped, Comprising: (A) is sectional drawing of the thread groove, (B) is the state which combined the seal lip with the thread groove. Cross section It is a figure which shows a prior art example, Comprising: (A) is principal part sectional drawing of the sealing device which concerns on a prior art example, (B) is explanatory drawing of the screw groove with which the sealing device is equipped.

  Next, embodiments of the present invention will be described with reference to the drawings.

First embodiment
FIG. 1 shows a cross section of a main part of a sealing device 1 according to an embodiment of the present invention.
The sealing device 1 according to this embodiment is a sealing device having a structure in which a seal lip 24 mounted on the non-rotating housing 51 side is slidably in contact with the axial end surface 13a of the seal flange 13 on the rotating shaft 61 side. The sealing fluid (oil) on the machine inner side (oil side) A is between the housing (seal housing) 51 and the rotary shaft 61 inserted through the shaft hole 52 provided in the housing 51. It is a sealing device (oil seal for engine) that seals so as not to leak. The sealing device 1 includes a combination of a lip seal member 21 attached to the inner periphery of the shaft hole 52 of the housing 51 and a slinger 11 attached to the outer periphery of the rotary shaft 61. 1 is provided, and the seal flange described in claim 1 is provided as a flange portion on the slinger 11.

  The slinger 11 is made of a rigid material such as metal, and has a sleeve portion 12 fixed (fitted) to the outer peripheral surface of the rotary shaft 61, and one axial end portion (an inner end portion) of the sleeve portion 12 in the axial direction. The surface of the machine-side end surface 13a, which is the other end surface in the axial direction of the flange portion 13 and includes the sliding region with respect to the seal lip 24, is integrally formed with the outward flange portion 13 provided on the surface. A portion (also referred to as a roughened portion or a surface roughened portion) 14 is provided. The surface including the sliding region is a band-like and annular surface having a predetermined radial width. The satin-finished portion 14 is obtained by imparting surface roughness to the flange portion 13 by shot blasting or the like, and as a result, many fine valleys (dents) are formed on the surface of the flange portion 13.

  On the other hand, the lip seal member 21 is attached (vulcanized and bonded) to the mounting ring 22 made of a rigid material such as metal that is fixed (fitted) to the inner peripheral surface of the shaft hole 52 of the housing 51. The rubber-like elastic body 23 has a seal lip (end face lip) 24 slidably in contact with the machine-side end surface 13 a of the flange portion 13 of the slinger 11, and the slinger 11 A non-contact oil recovery lip 25 is integrally provided, and a dust strip 26 slidably contacting the outer peripheral surface of the sleeve portion 12 of the slinger 11 is assembled to the rubber-like elastic body 23. The oil recovery lip 25 is disposed on the outside B of the seal lip 24, and the dust lip 26 is further disposed on the outside B of the oil recovery lip 25.

  The seal lip 24 is provided on the inner side A of the machine so as to gradually increase in diameter from the base end portion 24a to the tip end portion 24b and obliquely outward in the radial direction, and the inner periphery of the tip end portion 24b. The surface is in contact with the satin finish processing portion 14 provided on the machine end surface 13a of the flange portion 13. Further, for this contact, a predetermined tightening allowance (contact surface pressure) is set, so that the seal lip 24 is against the matte processing portion 14 provided on the outer end surface 13a of the flange portion 13 on the inner peripheral surface of the tip end portion 24b. Elastic contact with a predetermined tightening allowance.

  The sealing device 1 is not provided with a configuration corresponding to the screw groove 104 in the above-described prior art.

  In the sealing device 1 having the above-described configuration, the seal lip 24 is in contact with the matte processing portion 14 provided on the machine end surface 13a of the flange portion 13 at the tip portion 24b, and the rotating shaft 61 rotates in this state. When the flange portion 13 is driven to rotate, the distal end portion 24b of the seal lip 24 slightly floats outward in the radial direction by the action of centrifugal force generated along with the rotation, and the distal end portion 24b of the seal lip 24 and the flange portion 13 A fluid flow toward the outer diameter side is generated between the machine-side end face 13a through the space formed by the valley portion of the matte finish portion 14, thereby exhibiting a fluid pumping action. Therefore, the flange portion 13 that rotates together with the rotary shaft 61 exhibits a fluid swinging action due to centrifugal force, and the satin finish processing portion 14 exerts a fluid pumping action due to centrifugal force. It is possible to suppress leakage through the contact portion between the portions 13 to the outside B.

  Further, when the rotary shaft 61 is stationary, the seal lip 24 is elastically in contact with the matte processing portion 14 of the machine end surface 13a of the flange portion 13 at the tip end portion 24b. The gap between the tip 24b and the machine-side end surface 13a is filled with the tip 24b, including the space formed by the valleys of the satin finish processing part 14. Therefore, it is possible to suppress the sealing fluid inside the machine inside A from passing through the contact portion between the seal lip 24 and the flange part 13 and leaking to the machine outside B, thereby suppressing the occurrence of stationary leakage. can do.

Second embodiment ...
In the first embodiment, the matte finish portion 14 is provided on the end surface 13a of the flange portion 13 that includes the sliding area with respect to the seal lip 24. It may be provided on the flange portion 13 side and the seal lip 24 side.

  As an example, in the sealing device 1 shown in FIG. 2, the matte finish portion 14 is provided on a surface of the flange portion 13 that is the machine-side end surface 13 a including the sliding region with respect to the seal lip 24, and A satin finish portion 27 is also provided on the surface 24c including the sliding region with respect to the flange portion 13. As described above, the seal lip 24 comes into contact with the machine outer end surface 13a of the flange portion 13 at the inner peripheral surface of the tip end portion 24b. Therefore, the matte processing portion 27 is provided on the surface including the inner peripheral surface of the tip end portion 24b. ing.

Third embodiment
In the sealing device 1 shown in FIG. 3, the sealing fluid is disposed on the outer peripheral side (inside the machine) by exerting a fluid pumping action due to centrifugal force when the rotating shaft 61 rotates as shown in FIG. A thread groove 15 that exerts an action of pushing back toward A) is provided, and a textured portion 16 as shown in FIG. 5 is provided on the inner surface of the thread groove 15 that exhibits a fluid pumping action. In FIG. 4, an arrow e indicates the rotation direction of the rotation shaft 61. Then, when the textured portion 16 is provided on the inner surface of the screw groove 15 as described above, the thread groove 15 is compared with the case where the textured portion is not provided on the inner surface of the screw groove 15 as shown in the comparative example of FIG. Since the surface area of the inner surface of the sealing fluid increases, the surface tension of the sealing fluid is easily generated, and the sealing fluid is less likely to flow through the screw groove 15. Therefore, it becomes difficult for the sealing fluid to flow in the thread groove 15 as described above, thereby suppressing the occurrence of stationary leakage.

  In the example shown in FIG. 5, a screw groove 15 having a triangular cross section (an isosceles triangle with the groove opening as a base) is provided on the machine end face 13 a of the flange portion 13. The satin processing part 16 is provided in 15b, respectively.

  Since the slinger 11 is made of a rigid material such as metal, the shape of the satin finish portion 16 can be maintained for a longer period of time than when the satin finish portion is provided on the surface of the seal lip 24 made of a rubber-like elastic body. .

Fourth and fifth embodiments ...
In addition, in order to increase the surface area of the inner surface of the screw groove 15 that exhibits the fluid pumping action, the cross-sectional shape of the screw groove 15 is changed to a deformed cross section other than a triangle instead of providing the matte processing portion 16 on the inner surface of the screw groove 15. In this way, even when the cross-sectional shape of the screw groove 15 is an irregular cross-section other than a triangle, the surface tension of the sealing fluid is likely to occur, and the sealing fluid is less likely to flow through the screw groove 15, Generation | occurrence | production of a stationary leak can be suppressed.

  As an irregular cross-section other than a triangle, it is conceivable that the cross-sectional shape of the screw groove 15 is rectangular, trapezoidal, semicircular or arcuate.

  In FIG. 7 shown as the fourth embodiment, the cross-sectional shape of the thread groove 15 that exerts the fluid pumping action is a rectangle (a rectangle having a groove opening as a long side). The screw groove 15 having a rectangular cross section has a constant groove width and groove depth and a larger inner surface area than the screw groove 15 having a triangular cross section.

  In FIG. 8 shown as the fifth embodiment, the cross-sectional shape of the thread groove 15 that exhibits the fluid pumping action is an arc shape (an arc shape with the groove opening portion being a chord side). The thread groove 15 having a circular arc cross section has a larger inner surface area than the screw groove 15 having a triangular cross section.

  Therefore, also in these examples, it becomes difficult for the sealing fluid to flow in the thread groove 15, so that the occurrence of stationary leakage can be suppressed.

  Further, the cross-sectional shape of the screw groove 15 may be an irregular cross-section other than a triangle, and a matte finish portion may be provided on the inner surface of the screw groove 15.

DESCRIPTION OF SYMBOLS 1 Sealing device 11 Slinger 12 Sleeve part 13 Flange part (seal flange)
13a Machine outer end face (axial end face)
14, 16, 27 Finished portion 15 Thread groove 21 Lip seal member 22 Mounting ring 23 Rubber elastic body 24 Seal lip 24a Base end portion 24b Tip end portion 24c Inner peripheral surface 25 Oil recovery lip 26 Dustrip 51 Housing 52 Shaft hole 61 Rotation axis A Inside machine B Outside machine

Claims (4)

In a sealing device having a structure in which a seal lip mounted on a non-rotating housing side slidably contacts an axial end surface of a seal flange on a rotating shaft side,
A sealing device comprising a stationary leak suppression structure between the seal lip and the axial end surface of the seal flange. The sealing device according to claim 1.
The stationary leakage suppression structure is provided with a matte processing portion in one or both of a region in which the seal flange is slidably in contact with the seal lip and a region in the seal lip that is slidably in contact with the seal flange. Sealing device characterized by being The sealing device according to claim 1.
Provided with a thread groove that exerts a fluid pumping action when rotating on the axial end face of the seal flange,
The static leakage suppressing structure is a sealing device in which a matte finish is provided on the inner surface of the screw groove. The sealing device according to claim 1.
Provided with a thread groove that exerts a fluid pumping action when rotating on the axial end face of the seal flange,
The sealing device according to claim 1, wherein the static leakage suppression structure has a cross-sectional shape of the thread groove that is an irregular cross-section other than a triangle.

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