JP2004132524A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device capable of preventing the leakage of a sealed fluid at a wide range from a low speed to a high speed without narrowing a seal clearance. <P>SOLUTION: The seal clearance 25 is formed between a rotator 3 and a static section 5, and a movable floating ring 6 is arranged in this seal clearance 25. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sealing device that prevents leakage of a sealing fluid, and more particularly to a sealing device that can prevent leakage of a sealing fluid in a non-contact manner by rotation of a rotating body.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a sealing device for preventing leakage of a sealed fluid, a labyrinth seal capable of providing a seal gap between a rotating body and a stationary part and preventing leakage of the sealed fluid in a non-contact manner by rotation of the rotating body has been known. Have been. This labyrinth seal is particularly suitable for preventing oil leakage at a portion where low torque is required, and is used for, for example, a turbocharger (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-5-1559.
[0004]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional labyrinth seal, in order to prevent oil leakage during rotation of the rotating body (substantially negligibly small), it is necessary to narrow the seal gap and reduce the variation, that is, to precisely manage the gap. is there. Also, in order to prevent oil leakage during rotation, it is necessary to narrow the seal gap as the rotation speed increases. For example, when the rotation speed of the rotating body is 8000 rpm, it is necessary to form a seal gap provided between the rotating body and the stationary portion to about 0.1 mm.
[0005]
However, in order to form a seal gap of 0.1 mm in the conventional labyrinth seal, the processing accuracy of the labyrinth seal itself and the mounting accuracy of the labyrinth seal need to be extremely high. In order to increase the processing accuracy of the labyrinth seal, a high-precision device is required, and to manufacture a large number of labyrinth seals produced by such a device, an extremely large number of devices and places are required. However, there is a problem that the production efficiency is poor and the economic burden increases. Further, in order to increase the mounting accuracy of the labyrinth seal, a high-precision mounting device is still required, and there is a problem that the production efficiency is low and the economic burden increases.
[0006]
Therefore, there is a demand for a sealing device capable of preventing leakage of a sealing fluid over a wide range from a low speed to a high speed without reducing the sealing gap.
[0007]
The present invention has been made in view of this point, and an object of the present invention is to provide a sealing device that can prevent leakage of a sealing fluid over a wide range from low speed to high speed without narrowing a sealing gap. And
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the sealing device of the present invention according to the first aspect of the present invention is characterized in that a sealing gap is provided between a rotating body and a stationary portion, and leakage of a sealing fluid due to rotation of the rotating body. In a sealing device capable of preventing the contact in a non-contact manner, wherein a floating ring movable in the seal gap is provided. By adopting such a configuration, it is possible to reliably and easily prevent the leakage of the sealing fluid over a wide range from low speed to high speed without narrowing the seal gap by the effect of the floating ring.
[0009]
The sealing device of the present invention according to claim 2 is characterized in that, in claim 1, the rotating member is provided with a sealing member for preventing leakage of sealing fluid from the sealing gap at least when rotation of the rotating member is stopped. On the point. By employing such a configuration, it is possible to reliably and easily prevent leakage of the sealed fluid when the rotation of the rotating body is stopped and at a low speed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to embodiments shown in the drawings.
[0011]
FIG. 1 is a sectional view showing a main part of a first embodiment of a labyrinth seal as a sealing device according to the present invention.
[0012]
As shown in FIG. 1, a labyrinth seal 1 as a sealing device according to the present embodiment is configured such that a rotating member 3 mounted on a rotating shaft 2 as a rotating body and a housing 4 as a stationary portion face the rotating member 3. And a floating ring 6. The left side of the labyrinth seal 1 in FIG. 1 is a sealing side OS where lubricating oil as a sealing fluid is present, and the right side of the labyrinth seal 1 in FIG. 1 is an atmosphere side AS.
[0013]
The rotary member 3 is integrally formed by baking a rotary member elastic seal 8 made of a rubber-like elastic body on an annular rotary member ring body 7 formed of metal or resin or the like.
[0014]
The rotating member ring 7 includes an inner cylindrical portion 9. The inner cylindrical portion 9 is formed to have a slightly larger diameter than the rotating shaft 2 and to have a predetermined length along the axial direction shown in the left-right direction of FIG. Have been. At the left end edge of the inner cylindrical portion 9 located on the sealing side OS, a substantially annular inner upright wall portion 10 which is bent radially outward at a substantially right angle toward the inner peripheral surface of the housing 4 extends. Is formed. The outer peripheral edge of the inner upright wall portion 10 is formed so as to be located at a substantially intermediate portion between the outer peripheral surface of the rotating shaft 2 and the inner peripheral surface of the housing 4. On the outer peripheral edge of the inner upright wall portion 10, an intermediate cylindrical portion 11 bent substantially at right angles toward the atmosphere side AS is formed extending in the axial direction. The length of the intermediate cylindrical portion 11 is shorter than the length of the inner cylindrical portion 9, and the right end of the intermediate cylindrical portion 11 is bent outward at a substantially right angle toward the inner peripheral surface of the housing 4. A substantially annular rotating side seal gap forming wall portion 12 formed on the side surface extends. Further, an outer cylindrical portion 13 which is bent substantially at right angles toward the sealing side OS is formed on the outer peripheral edge of the rotating side seal gap forming wall portion 12 so as to extend in the axial direction.
[0015]
The rotating member elastic seal 8 includes a rotating shaft mounting portion 14 and a lip seal 15 as a sealing member for preventing oil leakage from a seal gap 25 described later at least when the rotation of the rotating shaft 2 is stopped.
[0016]
The one rotating shaft mounting portion 14 is arranged on the inner peripheral surface of the inner cylindrical portion 9 of the rotating member ring 7 and has an appropriate interference with the rotating shaft 2.
[0017]
The other lip seal 15 has a base located on the side of the inner upright wall 10 of the rotating member ring 7 located on the atmosphere side AS, and a lip tip 16 located on the atmosphere side AS. The lip seal 15 is formed so as to gradually increase in diameter from the side surface of the inner upright wall portion 10 on the atmosphere side AS toward the atmosphere side AS. When the rotation of the rotary shaft 2 is stopped, the lip end 16 of the lip seal 15 elastically contacts the seal contact surface 21 of the fixing member 5 described later with an appropriate tightening margin as shown by a broken line in FIG. When the rotating shaft 2 rotates, the lip tip 16 is formed to be separated from the seal contact surface 21 by the centrifugal force accompanying the rotation of the rotating shaft 2 as shown by the solid line in FIG.
[0018]
That is, the lip tip 16 of the lip seal 15 is formed so as to be able to contact and separate from the seal contact surface 21.
[0019]
The lip seal 15 of the present embodiment is configured such that the lip tip 16 abuts from the axial direction on a seal abutting surface 21 formed in a direction orthogonal to the axial direction. The contact surface 21 may be formed along the axial direction, and the lip tip 16 may contact the seal contact surface 21 from the radial outside.
[0020]
The fixing member 5 is integrally formed by baking a fixing member elastic seal 18 made of a rubber-like elastic body on an annular fixing member ring 17 made of metal or resin.
[0021]
The fixing member ring 17 has a horizontal cylindrical portion 19 whose outer peripheral surface is parallel to the axial direction facing the inner peripheral surface of the housing 4, and a diameter from a right end edge of the horizontal cylindrical portion 19 located on the atmosphere side AS. It is formed in a substantially L-shaped cross section having an inward flange-shaped fixed sealing gap forming wall portion 20 bent substantially at right angles toward the center of the direction. The inner peripheral surface of the horizontal tubular portion 19 is arranged so as to face the outer peripheral surface of the outer cylindrical portion 13 of the rotating member ring 7 at an appropriate distance in the attached state. Further, the side surface of the sealing side OS of the fixed side seal gap forming wall portion 20 is disposed to face the side surface of the rotating side seal gap forming wall portion 12 on the atmosphere side AS at a predetermined interval. That is, the fixed side seal gap forming wall portion 20 and the rotating side seal gap forming wall portion 12 are arranged substantially in parallel. Further, the vicinity of the inner peripheral side of the side surface of the sealing side OS of the fixed side seal gap forming wall portion 20 is a seal contact surface 21 with which the lip tip 16 of the lip seal 15 contacts when the rotating shaft 2 is stopped. ing.
[0022]
The fixed member elastic seal 18 covers the outer periphery of the horizontal cylindrical portion 19 of the fixed member ring 17 and the side surface of the air side AS of the fixed side seal gap forming wall portion 20 of the fixed member ring 17. The portion that covers the outer periphery of the horizontal tubular portion 19 is a housing mounting portion 22 having an appropriate interference with the inner peripheral surface of the housing 4.
[0023]
A floating ring 6 made of resin, metal, or the like is disposed between the rotation-side seal gap forming wall 12 and the fixed-side seal gap forming wall 20.
The floating ring 6 is arranged so as to be movable in the radial direction and the axial direction between the rotating side seal gap forming wall portion 12 and the fixed side seal gap forming wall portion 20.
[0024]
That is, the gap G between the rotating side seal gap forming wall portion 12 and the fixed side seal gap forming wall portion 20 is formed to be larger than the thickness T of the floating ring 6 in the axial direction. The gap 23 between the opposing surfaces of the rotating side seal gap forming wall 12 and the floating ring 6 and the gap 24 between the opposing surfaces of the fixed side seal gap forming wall 20 and the floating ring 6 are both used. A seal gap 25 is formed.
[0025]
That is, the size of the gap 23 between the opposing surface of the rotating side seal gap forming wall 12 and the floating ring 6 and the size of the gap 24 between the opposing surface of the fixed side seal gap forming wall 20 and the floating ring 6. In other words, the value obtained by subtracting the thickness T of the floating ring 6 from the interval G between the rotating-side seal gap forming wall 12 and the fixed-side seal gap forming wall 20 is the seal. It is the size of the gap 25.
[0026]
Note that the inner and outer diameters of the floating ring 6 are preferably of a size that does not come into contact with the lip seal 15 when the rotation shaft 2 is stopped and when the rotation shaft 2 is rotating.
[0027]
Next, the operation of the present embodiment having the above-described configuration will be described.
[0028]
According to the labyrinth seal 1 of the present embodiment, when the rotation of the rotating shaft 2 is stopped and at a low speed, the lip tip 16 of the lip seal 15 has its own elastic restoring force, as shown by the broken line in FIG. 5 is resiliently in contact with the seal contact surface 21 of FIG. 5, it is possible to reliably and easily prevent oil leakage from the sealing side OS to the atmosphere side AS.
[0029]
When the rotation shaft 2 starts rotating, the lip tip 16 of the lip seal 15 elastically deforms radially outward due to centrifugal force accompanying the rotation of the rotation shaft 2 as the rotation increases. Due to this elastic deformation, the lip tip 16 of the lip seal 15 expands, and the lip tip 16 of the lip seal 15 separates from the seal contact surface 21 as shown by the solid line in FIG. As a result, when the rotating shaft 2 rotates, the lip tip 16 of the lip seal 15 and the seal contact surface 21 can be kept in a non-contact state. The lip tip 16 of the lip seal 15 separated from the seal contact surface 21 by the centrifugal force accompanying the rotation of the rotating shaft 2, when the rotation of the rotating shaft 2 becomes slow or stops, its own elastic restoring force causes the sealing contact. It easily returns to the original state in contact with the contact surface 21.
[0030]
Therefore, according to the labyrinth seal 1 of the present embodiment, it is possible to reliably and easily prevent oil leakage when the rotation of the rotating shaft 2 is at a low speed or stopped.
[0031]
Further, according to the labyrinth seal 1 of the present embodiment, when the rotation shaft 2 starts rotating, as the rotation increases, the oil present on the sealing side OS is accompanied by the rotation of the rotation member 3 mounted on the rotation shaft 2. Due to the centrifugal force, the fluid flows so as to stick to the inner peripheral surface side of the fixing member 5, and a part of the fluid flows from the sealing side OS to the atmosphere side AS through the sealing gap 25. However, the oil that is going to flow out to the atmosphere side AS through the seal gap 25 is captured by being rotated in a laminar flow state by the floating ring 6 disposed in the seal gap 25 and is prevented from flowing out to the atmosphere side AS. Thus, leakage of oil to the atmosphere side AS is prevented.
[0032]
At this time, since the floating ring 6 is movably disposed in the seal gap 25, the floating ring 6 rotates at a speed lower than the rotation speed of the rotary shaft 2 due to the contact with the oil, and forms the rotation-side seal gap. Of the oil existing in the gap 23 between the opposing surfaces of the wall 12 and the floating ring 6 and the pressure of the oil existing in the gap 24 between the opposing surfaces of the fixed seal gap forming wall 20 and the floating ring 6. Move axially to balance pressure. That is, the floating ring 6 is self-centered so as to be held coaxially with the rotating shaft 2 and to hold the gaps 23 and 24 formed on the left and right sides of the floating ring 6.
[0033]
According to the labyrinth seal 1 of the present embodiment, since the floating ring 6 is disposed between the rotating side seal gap forming wall 12 and the fixed side seal gap forming wall 20, the seal gap 25 is formed. The oil can be reliably and easily prevented from leaking to the atmosphere side AS over a wide range from low speed to high speed without reducing the size of the oil.
[0034]
This could be confirmed by a performance evaluation test. In this performance evaluation test, as shown in FIG. 2 (a), a metal having a substantially L-shaped cross section was used as a substitute for the rotating member 3 on the outer peripheral surface of a rotating shaft having an outer diameter of 80 mm. Made of a rotating side vertical wall 31 made of stainless steel, and an annular body having a substantially L-shaped cross section as a substitute for the fixing member 5 on the inner peripheral surface of the housing 4 having an inner diameter of 100 mm and transparent from the atmosphere side AS perpendicular to the axial direction. A fixed resin vertical wall 32 is provided, the floating ring 6 is disposed between the rotating vertical wall 31 and the fixed vertical wall 32, and 0.5 mm (rotating vertical wall 31 and fixed vertical wall 32) is provided. The present invention is provided with a seal gap 25 of a value obtained by subtracting the thickness T of the floating ring 6 from the gap G between the wall 32 and the vertical wall of the rotating side as shown in FIG. Without disposing the floating ring 6 between the base 31 and the fixed vertical wall 32. Those provided Lumpur gap 25 is used as the conventional product. Further, the size of the seal gap 25 of the conventional product is 0.1 mm (conventional product 1), 0.2 mm (conventional product 2), 0.3 mm (conventional product 3), and 0.4 mm (conventional product 4). The type was used.
[0035]
Then, for the product of the present invention and the conventional product, using a lubricating oil as a sealing fluid, that is, Castle SL 5W-20 (trade name, manufactured by Toyota), the oil temperature of the lubricating oil was set to 150 ° C. The amount of oil leakage when rotating at seven stages of 750, 2000, 3000, 4500, 6000, 7000, and 9000 rpm was evaluated. The lubricating oil was supplied to the sealing side OS while the rotating shaft 2 was rotated. The amount of oil leakage is obtained by measuring the amount of lubricating oil leaked to the atmosphere side AS 30 minutes after the supply of the lubricating oil to the sealing side OS.
[0036]
FIG. 3 shows the results of the performance evaluation test.
[0037]
As shown in FIG. 3, the product of the present invention was found to have good sealing performance without oil leakage in the entire rotation range (750 to 9000 rpm) even when the seal gap 25 was 0.5 mm.
[0038]
On the other hand, the performance of the conventional product was inferior to that of the product of the present invention even though the seal gap 25 was smaller than that of the product of the present invention. That is, the conventional products 1 to 4 all suffered from oil leakage and could not prevent oil leakage. More specifically, as shown in FIG. 3, the conventional products 1 and 2 have oil leakage when the rotation speed of the rotating shaft 2 exceeds 4500 rpm, even though the seal gap 25 is extremely small at 0.1 mm and 0.2 mm. Occurred. Further, in the conventional products 3 and 4, although the seal gap 25 is 0.3 mm and 0.4 mm smaller than that of the present invention, oil leakage occurs when the rotation speed of the rotating shaft 2 exceeds 2000 rpm, and oil leakage occurs. The amount was large. The oil leakage at 9000 rpm of the conventional product was 0.3 cc / min for the conventional product 1, 0.5 cc / min for the conventional product 2, 5.4 cc / min for the conventional product 3, and 8.4 cc / min for the conventional product 4. min.
[0039]
In the performance evaluation test, in a state where there is no oil leakage, the oil surface, which is a boundary portion between the oil and the atmosphere, is annularly held in the seal gap 25, and the oil surface may rotate in a laminar flow state. found. In addition, it was found that the state of the oil leak was caused by the oil surface being distorted in a wavy manner, a part of the oil surface being separated and scattered to the atmosphere side AS.
[0040]
The labyrinth seal of the present invention has good sealing performance despite the fact that the seal gap is wider than the conventional product because the floating ring arranged in the seal gap is slower than the rotation speed of the rotating shaft with the rotation of the rotating shaft. This is because, by rotating at a speed, the oil level in the seal gap is annularly maintained in a laminar flow state without being disturbed.
[0041]
In addition, when the labyrinth seal 1 of this embodiment was manufactured and a performance evaluation test was performed using an actual product, it was confirmed that there was no oil leakage and good sealing performance was obtained in the entire rotation range (0 to 9000 rpm).
[0042]
Therefore, according to the labyrinth seal 1 of the present embodiment, the seal gap 25 can be set wider than before, so that the size of the seal gap 25 is not narrowed, and the sealing fluid is spread over a wide range from low speed to high speed. Leakage can be reliably and easily prevented. As a result, the tolerance in manufacturing the labyrinth seal 1 and the mounting accuracy of the labyrinth seal 1 can be reduced, and the play in the axial direction of the rotating shaft 2 can be absorbed, so that productivity is improved and cost is reduced. Can be easily achieved.
[0043]
FIG. 4 shows a second embodiment of the labyrinth seal according to the present invention. The labyrinth seal 41 of this embodiment is one in which the rotating member 3, the fixed member 5, and the floating ring 6 are integrated so as not to be separated.
[0044]
That is, the labyrinth seal 41 of the present embodiment prevents the rotating member 3 and the floating ring 6 arranged inside the fixed member 5 from moving in the axial direction and separating from the fixed member 5 during handling or the like. By providing an inward flange-like separation preventing wall 42 that is bent at substantially a right angle toward the radial center at the left end edge of the horizontal tubular portion 19 of the fixing member ring 17 constituting the fixing member 5. It is configured. After the floating ring 6 and the rotating member 3 are housed inside the fixed member 5, the separation preventing wall 42 is formed in a horizontal direction that is long and thin in the axial direction by an amount necessary to form the separation preventing wall 42 in advance. It is formed by bending the left end of the cylindrical portion 19 toward the center in the radial direction. Other configurations are the same as those of the labyrinth seal 1 of the first embodiment described above, and detailed description thereof will be omitted.
[0045]
With such a configuration, the labyrinth seal 41 of the present embodiment can provide the same effect as the labyrinth seal 1 of the above-described first embodiment, and the rotating member 3, the fixed member 5, and the floating ring 6 are not separated. Therefore, both the handleability and the workability when attaching the labyrinth seal 41 to the rotating shaft 2 and the housing 4 can be improved.
[0046]
FIG. 5 shows a labyrinth seal according to a third embodiment of the present invention. The labyrinth seal 51 of the present embodiment has a fixed side seal gap forming wall portion 20 provided in a part of the housing 4 as a stationary portion.
[0047]
That is, in the labyrinth seal 51 of the present embodiment, the fixed side seal gap forming wall portion 20 is provided in a part of the housing 4 itself, and the inner peripheral edge of the fixed side seal gap forming wall portion 20 is sealed. A tubular portion 52 that is bent substantially at right angles in the axial direction toward the side OS extends. The lip tip 16 of the lip seal 15 provided on the rotating member 3 is formed such that the lip tip 16 of the lip seal 15 provided on the rotating member 3 comes into contact with the outer peripheral surface of the cylindrical portion 52 from the outside in the radial direction when the rotation of the rotating shaft 2 is stopped and at low speed. The outer peripheral surface of the cylindrical portion 52 with which the lip tip 16 abuts is the seal abutment surface 21 (see the broken line in the figure). The lip tip 16 of the lip seal 15 may be brought into contact with the side surface of the fixed-side seal gap forming wall portion 20 located on the sealing side OS without providing the tubular portion 52.
[0048]
Other configurations are the same as those of the labyrinth seal 1 of the first embodiment described above, and detailed description thereof will be omitted.
[0049]
With such a configuration, the labyrinth seal 51 of the present embodiment can achieve the same effect as the labyrinth seal 1 of the above-described first embodiment.
[0050]
The sealing device of the present invention can be used for preventing leakage of a sealed fluid composed of a liquid or a mixture of a liquid and a solid in an engine or a pump shaft requiring low torque.
[0051]
Further, the present invention is not limited to the above embodiments, and can be variously modified as needed.
[0052]
【The invention's effect】
As described above, according to the sealing device of the first aspect of the present invention, it is possible to reliably and easily prevent the leakage of the sealing fluid over a wide range from low speed to high speed without narrowing the sealing gap. It produces extremely excellent effects such as being able to.
[0053]
Further, according to the sealing device of the present invention according to claim 2, there is an extremely excellent effect that leakage of the sealed fluid can be reliably and easily prevented when the rotation of the rotating body is stopped and at a low speed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of a labyrinth seal as a sealing device according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view showing a configuration of a labyrinth seal used in a performance evaluation test; Fig. 3 shows a product of the present invention, and Fig. 3 (b) shows a conventional product. Fig. 3 is a diagram showing the relationship between the number of rotations of a rotating shaft and the amount of oil leakage. Fig. 4 is a second embodiment of a labyrinth seal as a sealing device of the present invention. FIG. 5 is a view similar to FIG. 1 showing a main part of FIG. 5. FIG. 5 is a view similar to FIG. 1 showing a main part of a third embodiment of a labyrinth seal as a sealing device of the present invention.
1, 41, 51 Labyrinth seal 2 Rotary shaft 3 Rotary member 4 Housing 5 Fixed member 6 Floating ring 12 Rotary side seal gap forming wall 15 Lip seal 16 Lip tip 20 Fixed side seal gap forming wall 21 Seal contact surface 23, 24 Gap 25 Seal gap 42 Separation preventing wall 52 Cylindrical portion G Interval T (between the rotating seal gap forming wall and the fixed seal gap forming wall) Thickness (of floating ring) AS Atmospheric OS Sealed side

Claims (2)

In a sealing device capable of providing a sealing gap between a rotating body and a stationary part and preventing leakage of a sealed fluid in a non-contact manner by rotation of the rotating body,
A sealing device comprising a floating ring movable in the seal gap. The sealing device according to claim 1, wherein a seal member is provided on the rotating body to prevent leakage of a sealed fluid from the sealing gap at least when the rotation of the rotating body is stopped.

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