WO2005040649A1

WO2005040649A1 - Non-contact oil seal mechanism for rotating shaft

Info

Publication number: WO2005040649A1
Application number: PCT/JP2004/014843
Authority: WO
Inventors: Jun Akita; Tomoyuki Takahashi
Original assignee: Komatsu Ltd.
Priority date: 2003-10-29
Filing date: 2004-10-07
Publication date: 2005-05-06
Also published as: JPWO2005040649A1; CN1806139A; CN100476270C; DE112004000627T5

Abstract

A non-contact oil seal mechanism for a rotating shaft installed in a rotary machine which has the rotating shaft (12) and a casing in which a casing hole (3) rotatably holding the rotating shaft (12) is formed and in which the rotating shaft (12) is held in the casing hole (3) with a clearance t so as to come into non-contact with each other and lubricating oil flows through the clearance (t). The seal mechanism comprises an oil recovery chamber (4) formed in the inner peripheral surface of the casing hole (3) along the circumferential direction of the rotating shaft (12) and recovering the lubricating oil and a plurality of oil cutting grooves (5) formed in the outer peripheral surface of the rotating shaft (12) along the circumferential direction of the rotating shaft (12), arranged along the axial direction of the rotating shaft (12), and opposed to the oil recovery chamber (4). The plurality of oil cutting grooves (5) are formed to be stored within the axial width dimension W1 of the oil recovery chamber (4).

Description

Specification

Non-contact oil seal mechanism for rotating shaft

Technical field

The present invention relates to a lubricating oil seal mechanism for a rotating part of a rotating machine, and more particularly to a rotating shaft having a function of preventing the lubricant from leaking outside by being in non-contact with the rotating shaft. The present invention relates to a non-contact type oil seal mechanism.

Background art

[0002] In general, a seal mechanism is provided at a portion of a rotating machine or the like that penetrates a casing of a rotating shaft so as to prevent intrusion of dust and the like from outside the casing and leakage of lubricating oil from inside the casing to the outside. Have been. As this sealing mechanism, contact-type seals such as o-rings, oil seals, and mechanical seals are often used. However, in a contact-type sealing mechanism, a member that is in contact with a rotating shaft is worn out or deteriorates due to aging over a long period of operation, and does not serve as a seal. This often requires frequent replacement of parts.

[0003] For this reason, a non-contact type sealing mechanism that can exhibit a sealing function without contacting the shaft may be employed. Such a non-contact type seal mechanism is employed in a device in which parts cannot be easily replaced, and includes a static pressure seal and a labyrinth seal. For the hydrostatic seal, for example, two annular grooves are provided so as to surround the shaft, adjacent to the part where the rotating shaft protrudes to the outside or the bearing, such as a casing, and the gas is sent to one of the annular grooves. When the other annular groove force is exhausted, a thin, gaseous film is formed between the shaft and the inner peripheral surface of the through-hole to prevent oil from leaking to the outside. It is known (for example, see Patent Document 1).

[0004] Furthermore, the labyrinth seal is provided with a number of fin-shaped seal fins on an inner peripheral surface of a hole through which a rotating shaft penetrates a wall of a casing or the like, and the distance between the tip of the fin and the shaft is minute. The annular space formed between the fins allows oil that leaks to the outside along the shaft surface to intersect the flow due to the pressure difference between the inside and the outside of the casing. The expansion and expansion of the air gap is attenuated by the compression action, eliminating the differential pressure and oil leakage (See, for example, Patent Document 2).

Patent Document 1: JP-A-48-100554

Patent Document 2: JP-A-6-330893

Disclosure of the invention

Problems to be solved by the invention

[0006] However, non-contact type seal mechanisms such as the static pressure seal and the labyrinth seal have the following problems as the seal mechanism. That is, in the case of a static pressure seal, a pressurized fluid (mainly air) for the seal must always be supplied during operation. Of course, a separate source of the pressure fluid is required.

Therefore, it is necessary to add extra equipment and control its operation, and to use it, it is effective only for specific equipment that can easily secure the supply source of the pressure fluid.

[0007] Although the labyrinth seal seems to be structurally simple, it requires machining accuracy and requires some contrivance in assembling, resulting in a high cost. Of course, if the assembly accuracy is not good, there is a problem that the sealing effect is significantly reduced.

On the other hand, if a contact-type seal is used as a seal mechanism for the shaft of a rotating machine in a mechanical facility that cannot be easily maintained after installation as described above, a long-term sealing effect cannot be expected, and However, it is difficult to expect the effect of the non-contact type sealing mechanism as described above.

[0008] The present invention has been made in view of such circumstances, and as a non-contact type seal having a simple structure, a non-contact type rotary shaft capable of achieving its purpose for a long period of time. It is an object of the present invention to provide an oil seal mechanism.

Means for solving the problem

In order to achieve the above object, a non-contact oil seal mechanism for a rotating shaft according to the first invention comprises a rotating shaft and a casing having a casing hole for rotatably holding the rotating shaft. A non-contact type oil seal mechanism provided in a rotary machine in which the rotating shaft is kept in a non-contact state with the casing hole, and a lubricating oil flows through the gap. Formed on the inner surface of the casing hole along the circumferential direction of the shaft An oil recovery chamber for recovering the lubricating oil, and an oil recovery chamber formed on an outer peripheral surface of the rotation shaft along a circumferential direction of the rotation shaft and arranged along an axial direction of the rotation shaft. And a plurality of oil cut grooves facing each other, wherein the plurality of oil cut grooves are formed so as to fit within the same width dimension of the oil recovery chamber.

[0010] The non-contact type oil seal mechanism for a rotary shaft according to the second invention is the non-contact type oil seal mechanism for a rotary shaft according to the first invention, wherein the protrusion formed between the adjacent grooves is the same as that of the first aspect. It is characterized in that the edges are angular.

A non-contact oil seal mechanism for a rotating shaft according to a third invention is the non-contact oil seal mechanism for a rotating shaft according to the first and second inventions, wherein the recovery chamber is arranged along an axial direction of the rotating shaft. A plurality of grooves are formed on the rotating shaft at positions corresponding to the respective oil recovery chambers.

[0011] A non-contact oil seal mechanism for a rotating shaft according to a fourth invention is an oil bath that stores lubricating oil to be supplied to the gap, in comparison with the non-contact oil seal mechanism for a rotating shaft according to the third invention. And a drain pipe for communicating the lubricating oil collected in each oil recovery chamber to the oil bath, and the drain pipes are formed independently for each oil recovery chamber. It is characterized by having.

The invention's effect

[0012] According to the first invention, the lubricating oil adhering to the surface of the rotating shaft is moved from the inside to the outside due to a pressure difference between the inside and the outside of the casing hole (internal pressure increases due to a rise in the temperature of the rotation drive mechanism). The lubricating oil moves in the axial direction due to the protrusions formed between the grooves of the plurality of oil cut grooves provided on the shaft at the position of the oil recovery chamber formed on the casing hole side. The speed can be reduced.

As a result, the lubricating oil retained in the ridges between the adjacent grooves is shaken down into the oil recovery chamber by the centrifugal force caused by the rotation of the rotating shaft.

Therefore, the lubricating oil supplied to the gap is prevented from leaking to the outside of the casing. The sealing function can be maintained over a period.

By the way, according to the present invention, in a shaft rotating at a low speed, a case caused by the operation of the rotating machine is provided. Even if the difference between the internal pressure and the external pressure (atmospheric pressure) is great, the oil that is about to leak can be stopped and recovered by the configuration in which the oil cut groove and the oil recovery chamber correspond to each other. .

[0013] By adopting the configuration of the second invention, even if the rotation of the rotating shaft is at low speed, the peripheral edge of the ridge is formed in an angular shape, so that the surface tension of the edge causes the oil to move in the axial direction. The function of reducing the speed acts to effectively separate the adhering oil from the rotating shaft force.

Therefore, even if the lubricating oil that moves along the shaft surface moves sequentially over the intermittent oil cut groove, and even if the centrifugal force due to the rotation of the shaft is small, oil lubrication can be performed by a plurality of ridges. Can do

[0014] By adopting the configuration of the third invention, a set of an oil-cutting groove and an oil recovery chamber capable of exhibiting the same function as the first invention is arranged at a plurality of locations, so that the set is provided inside and outside the casing hole. Due to the pressure difference described above, the oil to be leaked is prevented in multiple stages, and the speed is reduced and the flow of the oil is stopped every step.

By employing the configuration of the fourth invention, the oil recovered by the oil recovery mechanism consisting of the inner oil recovery chamber and the corresponding oil cut groove is passed through the drain pipe to the oil recovery chamber disposed outside. This has the effect of preventing backflow and oil leakage. In short, by providing a drain pipe independently for each oil recovery chamber, it is possible to prevent a backflow phenomenon of the oil recovered without connecting the front and rear oil recovery chambers, and to reliably prevent oil leakage.

Brief Description of Drawings

FIG. 1 is a cross-sectional view showing a specific example of a non-contact oil seal mechanism of a rotary roller according to the present invention.

FIG. 2 is an enlarged partial cross-sectional view of a main part of the embodiment.

[FIG. 3A] FIG. 3A is a cross-sectional view of a test device used to verify the function of the non-contact oil seal mechanism of the present invention.

FIG. 3B is an enlarged sectional view of a main part of the test apparatus.

FIG. 4A is a cross-sectional view of a main part of the test apparatus according to the present invention.

[FIG. 4B] FIG. 4B is a graph showing a relationship between the test apparatus and the pressure at which the gas leaks out. FIG. 5A is a cross-sectional view of another main part of the test apparatus according to the present invention.

[FIG. 5B] FIG. 5B is a graph showing the relationship between the above-mentioned test apparatus and the pressure at which the leaking sound starts. Explanation of symbols

[0016] 1 ... non-contact type oil seal mechanism, 3 ... casing hole, 4 ... oil recovery chamber, 4 mm, 4 mm ... space, 5 ... oil cut groove, 6 ... ridge, 6a ... edge of ridge , 11 ... casing, 12 ... rotating shaft, 14 ... housing cover, 15 ... bearing, 16 ... drain line, t ... gap

BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment of a non-contact type oil seal mechanism of a rotating shaft according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a specific example of a non-contact type oil seal mechanism of a rotating shaft according to the present invention. FIG. 2 shows an enlarged partial cross-sectional view of a main part. The rotary shaft non-contact type oil seal mechanism 1 (hereinafter simply referred to as the oil seal mechanism 1) shown in FIG. 1 is attached to a portion of the rotating shaft 12 that rotates at a low speed and protrudes outside from the bearing portion 15 of the rotating machine 10. It is a specific example of the provided embodiment.

[0018] The oil seal mechanism 1 is a rotary shaft of an input unit provided in a casing 11 of the rotary machine 10.

It is provided in a housing cover 14 attached to the outside of a bearing housing 13 for supporting the bearing 12.

The oil seal mechanism 1 includes a plurality of oil recovery chambers 4 formed on the inner peripheral surface of the casing hole 3 and a plurality of oil recovery chambers 4 provided on the outer peripheral surface of the rotary shaft 12 according to the position of each oil recovery chamber 4. A cut groove 5 and a plurality of drain pipes 16 provided in each oil recovery chamber 4 are provided.

A rotating body (not shown) is attached to the rotating shaft 12 at a shaft end that protrudes therethrough. When the rotating body rotates, the rotating shaft 12 is supported by the bearing portion 15 and the rotating shaft 12 is rotated. The lubricating oil flows through the gap t between the casing holes 3 to achieve smooth rotation. Note that the smaller the gap t is, the better. However, since the rotating shaft 12 must not come into contact with the housing cover 14 during the rotation of the rotating shaft 12, it is generally preferable to secure a clearance of about 0.5 mm. Better ,.

As shown in FIG. 2, each of the oil recovery chambers 4 is configured as a concave groove having a rectangular cross section, and the inner peripheral surface of the casing hole 3 closer to the end of the rotary shaft 12 than the bearing 15. Formed in two places The concave groove is continuous so as to make a round along the circumferential direction of the rotating shaft 12. In the present embodiment, the width W1 of the inner oil recovery chamber 4 along the rotation axis is set to, for example, 2 Omm, and the depth D1 is set to, for example, 20 mm.

A drain pipe 16 is connected to the bottom of the concave groove of each oil recovery chamber 4, and the drain pipe 16 connected to the oil recovery chamber 4 formed inside in FIG. As a result, the other end of the drain pipe 16 is connected to a force oil bath (not shown). This oil bath stores lubricating oil in order to supply the lubricating oil to the bearing 15, and the lubricating oil collected in the oil recovery chamber 4 is returned to the oil bath via the drain line 16. . In the present embodiment, since the inner diameter of the portion of the drain line 16 communicating with the oil recovery chamber 4 is desirably as large as possible, it is 18 mm φ, which is slightly smaller than the width of the oil recovery chamber 4. It has been. The reason for setting the drain pipe 16 to such a diameter is that the lubricating oil that has fallen into the oil recovery chamber 4 from the oil kerf 5 described later must be collected promptly so that the lubricating oil stays in the oil recovery chamber 4. Then, it may leak into the gap t again.

[0020] Such a drain pipe 16 is formed by drilling a hole or the like upward from a bottom portion (a lower surface in FIG. 2) of the casing 11 and further crossing the hole from a direction perpendicular to the rear end surface of the casing 11 so as to cross the hole. The holes can be formed by, for example, forming holes by closing the end surfaces of the holes with a packing (sealing member) such as an elastic member.

In FIG. 1, a drain pipe similar to the above is formed in the outside (right side in FIG. 1) oil recovery chamber 4 so as to reach the oil bath independently of the drain pipe 16. If this is described in 1, the drain pipes will intersect, so the drawing is omitted for convenience. Further, a seal ring 18 is additionally provided outside the outer oil recovery chamber 4 so as to close the casing hole 3. The seal ring 18 is made of a soft material and functions as an auxiliary seal member of the oil seal mechanism 1.

The oil cut groove 5 is a groove formed so as to make a full circumference in the circumferential direction of the outer peripheral surface of the rotating shaft 12, and as shown in FIG. It is engraved on the rotating shaft 12 as a group of multiple oil kerf grooves 5.

In the group of the oil kerf 5, a plurality of grooves are formed at required intervals with a narrow width. In this group of oil kerf 5, a groove is formed between adjacent oil kerfs 5 by engraving. Article 6 is formed.

The ridges 6 are preferably formed such that both ends 6a, which are corners of the radial end of the rotating shaft 12, are angular. In this way, the axial speed of the oil adhering to the shaft peripheral surface and flowing out with the rotation is reduced by the surface tension at the tip of the ridge 6 that connects to the oil cut groove 5, and the oil's axial speed is reduced by the surface tension. It is effective to shake off.

Here, the width and depth of each oil-cutting groove 5 are determined by the shape of both ends 6 a of the ridge 6 and the length of the end surface of the ridge 6 at the radial end of the rotating shaft 12. Therefore, the width dimension W2 and the depth dimension D2 of the oil groove 5 have basically no correlation with the diameter of the rotating shaft 12 (120 mm φ in the present embodiment). In the present embodiment, the width dimension W2 and the depth dimension D2 of each oil kerf groove 5 are approximately 3 mm.

In addition, if the group of the oil kerf 5 is not formed as at least two or more groups, the effect will not be produced.For example, if only one oil kerf is provided for one oil recovery chamber, the present invention The effect cannot be achieved. In the present embodiment, three oil kerfs 5 are formed per group, and two ridges 6 are formed between them. The width dimension W3 of the ridge 6 is substantially equal to the width of the oil kerf 5. The width W4 of the group of three oil kerfs 5 is set to W1> W4 so as to be accommodated in the oil recovery chamber 4 having the width W1. Furthermore, the longer the distance W5 between the groups of the oil kerf grooves 5 arranged in each recovery chamber 4 is, the longer the lubricating oil flows and the more preferable the lubricating oil leakage is, but in the present embodiment, It is set to 20 mm due to the size limitation of the casing cover 14.

Next, the operation of the thus configured oil seal mechanism 1 will be described.

The oil seal mechanism 1 is provided in a casing hole 3 protruding outside from a bearing 15 of a rotating shaft 12 rotating at a low speed.

In the rotating machine 10 provided with the oil seal mechanism 1, when the pressure inside the casing 11 becomes higher than the atmospheric pressure outside the casing, the pressure difference is formed between the outer circumference of the rotating shaft 12 and the inner circumference of the casing hole 3. The phenomenon that the oil is pushed out from the inside of the casing 11 to the outside through the small gap t and leaks out easily occurs.

At the position where the oil seal mechanism 1 of the present embodiment is provided, the oil moving from the inside to the outside along the peripheral surface of the rotating shaft 12 faces the portion of the oil recovery chamber 4. do it Since the horizontal line (both ends 6a of the ridge 6) of the oil groove 5 provided is formed angularly, the speed in the axial direction is reduced by the action of surface tension, and the oil is removed from the shaft surface by gravity. The oil that has not been shaken off here is shaken off again by the ridges 6 of the adjacent oil kerf 5. The oil dropped in the oil cut groove 5 is thereafter sequentially shaken down to the oil recovery chamber 4 side by the above operation and separated, and the oil adhering to the shaft surface is gradually removed.

[0025] In this way, the movement of most of the oil is prevented at the first oil groove group location 5A. However, if the pressure inside the casing further increases for some reason, the movement speed of the oil increases. And the lowering effect may not be sufficiently exhibited.

Therefore, the oil that moves without being able to be sealed by the first seal mechanism la is prevented from moving by the second seal mechanism lb that is provided a little apart in the manner described above. .

[0026] In the second seal mechanism lb, the movement of the oil that could not be removed by the first seal mechanism la is transferred again to the group of the oil cut grooves 5 provided on the shaft side at the corresponding position and the oil recovery chamber. 4 removes oil adhering to the shaft 12 as described above.

In the space 4B formed by the second oil recovery chamber 4, even if all the oil cannot be recovered in the space 4A by the first oil recovery chamber, the pressure around the second seal mechanism lb Since the difference (pressure difference between the spaces 4A and 4B) becomes smaller, the axial velocity of the oil ejected from the second seal mechanism lb to the space 4B becomes smaller, and the oil is easily removed by the second seal mechanism lb. Is recovered and the function of the non-contact oil seal can be fully exhibited. In the above description, the drain pipe 16 provided in the first oil recovery chamber 4 and the drain pipe provided in the second oil recovery chamber 4 are omitted (the symbols are omitted because they are overlapped in the figure). Are connected to the casing 11 independently of each other to prevent the oil collected in the first oil recovery chamber from flowing back to the second pond recovery chamber through the drain pipe to cause oil leakage, A sealing function can be issued.

Example 1

Next, in order to verify the function of the non-contact type oil seal on the low rotation shaft, an experiment was performed according to the following example. In this example, the experiment was performed using the experimental apparatus shown in FIG. 3A. (Experimental example 1)

In the test device 20, a seal mechanism is incorporated adjacent to the front bearing housing 24 of the front and rear bearings 23, 23 'supporting the rotating shaft 22 penetrating the casing 21.

The rotating shaft 22 is driven by a variable speed motor 25 at a required rotation. As a seal mechanism, as shown in an enlarged view of a main part P in FIG. 3B, a gap t of a minute dimension is provided with the rotating shaft 22, and a decompression chamber 26 (corresponding to an oil storage chamber) is formed in front of the gap t. I did it. In addition, a transparent acrylic plate 27 was attached to the front end so that Uchike could be seen. With such a configuration, the support structure 28 was arranged on the base 29 so that the axis was inclined forward by 5 ° as a condition that oil leakage easily occurred.

Using the test apparatus as described above, a test was performed under the following conditions.

(1) Shaft diameter of rotating shaft 22 (Φ 120 rotating speed 1800rpm (high speed rotation)

"Rotation speed 20rpm (low speed rotation)

(2) Lubricating oil type and oil temperature used in the test

Oil type EO10 Oil temperature 38 ° C Kinematic viscosity 37cSt

Supply oil amount 30LZmin

It should be noted that air was sent into the casing 11 to check the pressure in the casing in order to cope with the increase in the pressure.

(3) Dimension of gap t: 0.5mm

Decompression chamber 26 width X depth = 20mm X 20mm

Oil cut groove on rotating shaft: None

Drain tube diameter: 18mm φ

[0029] According to the above experimental results, first, as a cause of oil leakage when the internal pressure of the casing increases, ( _a ) air flows backward from the casing 21 to the decompression chamber 26 via the drain 30 and It was visually confirmed that the dropped oil generated a drainage leak due to the drainlo 13 (force also being sprayed up) and (b) a jet leak caused by the oil passing through the gap t being ejected at a certain flow velocity in the axial direction. (a) It is obvious that there is a cause of oil leakage, so the larger the diameter of the drain 30 is, the better in terms of sealing performance. In this case, it was found that connecting the drain pipes to the casing independently provided better sealing performance.

(Experiment 2)

From the above results, as shown in FIG. 4A, as a countermeasure against jet leakage, a structure was provided in which the rotary shaft 22 was provided with an oil cut groove 32 so as to face the pressure reducing chamber 26. The test was performed in the same manner as in Example 1 and compared with that of the structure shown in FIG. 3B.

Here, three oil cut grooves 32 are formed on the outer peripheral surface of the rotating shaft 12 at a position corresponding to the decompression chamber 26. The experiment was conducted with three oil cut grooves 32 formed, each having a width dimension X depth dimension of 3 mm X 3 mm, and a width dimension of a ridge between adjacent oil cut grooves of 3 mm. As a result, FIG. 4B is as shown by a graph comparing grooved and non-grooved. The pressure is shown as a relative value as 0.002MPa = l. When the rotary shaft was provided with an oil kerf (marked as groove), it was evident that at low speed rotation, the pressure at which the squirting leak started was about four times higher than without the groove.

In addition, it was visually confirmed that the ridge at the edge of the groove cut off oil due to surface tension. In other words, it turned out that the full edge was sharper and better.

In addition, at high speeds, the oil separated from the shaft by centrifugal force, so the pressure at the start of leaking was constant even if a grease was applied without a groove and the oil pressure was high.

(Experimental example 3)

Therefore, as shown in FIG. 5A, in place of the decompression chamber forming part 26A in the test apparatus, a part 26B having two parts 26 having decompression chambers 26 and 2 is exchanged, and corresponding to those decompression chambers. A plurality of oil-cutting grooves 32 were formed in the outer peripheral surface of the rotating shaft 22 for each of the decompression chambers 26 and 2 to perform oil-cutting. A test was performed in the same manner as in Experimental Example 1.

[0032] As a result of measuring the injection leak start pressure when two combinations of the decompression chamber and the oil cut groove were provided, as shown by a graph in FIG. It was evident that the pressure at which the leak started doubled, resulting in a 16-fold higher leaking pressure at the low-speed rotating shaft without grooves.

[0033] As described above, according to the oil seal mechanism of the present invention, the groove is not formed on the rotating pong side, and This makes it possible to maintain the injection leak starting pressure approximately 16 times higher than that of the conventional sealing method.In other words, compared to the conventional non-contact oil seal mechanism, the inside of the casing of the rotating machine and the rotation axis

Even if there is a large pressure difference between the outside and the outside of the protrusion, the injection of oil is prevented and the sealing effect can be enhanced.

[0034] Therefore, according to the present invention, the effect can be exhibited by adopting the seal portion of the rotating shaft that rotates at a low speed, so that the maintenance of the driving portion that is installed at a high position, such as a wind power generator, can be performed. Excellent effects can be expected when used in rotating parts of equipment that cannot be easily performed. Industrial applications

The present invention can be suitably adopted as a sealing mechanism of a rotating machine requiring long-term durability, and is suitably used as a sealing mechanism of a rotating mechanism used for wind power generation or the like, for example. Can be.

Claims

The scope of the claims

[1] A rotating shaft and a casing having a casing hole for rotatably holding the rotating shaft are provided, and the rotating shaft is held with a gap in which the casing is not in contact with the casing hole. A non-contact oil seal mechanism of a rotating shaft provided in a rotating machine in which lubricating oil flows through the gap,

An oil collection chamber formed on the inner peripheral surface of the casing hole along a circumferential direction of the rotation shaft, and configured to collect the lubricating oil;

A plurality of oil cut grooves formed on the outer peripheral surface of the rotating shaft along the circumferential direction of the rotating shaft, arranged along the axial direction of the rotating shaft, and facing the oil recovery chamber; A non-contact oil seal mechanism for a rotating shaft, wherein the plurality of oil cut grooves are formed so as to fit within the same width of the oil recovery chamber.

[2] The rotary shaft non-contact type oil seal mechanism according to claim 1,

A non-contact type oil seal mechanism for a rotating shaft, wherein a ridge formed between the adjacent grooves has a square edge.

[3] In the non-contact type oil seal mechanism for a rotating shaft according to claim 1 or 2, a plurality of the oil recovery chambers are formed along an axial direction of the rotating shaft.

The non-contact oil seal mechanism for a rotating shaft, wherein the plurality of grooves are formed on the rotating shaft at positions corresponding to the respective oil recovery chambers.

[4] The non-contact oil seal mechanism for a rotating shaft according to claim 3,

An oil bath for storing the lubricating oil supplied to the gap and each oil recovery chamber, and a drain pipe for returning the lubricating oil recovered in each oil recovery chamber to the oil bath;

The non-contact type oil seal mechanism of a rotating shaft, wherein the drain pipe is formed independently for each oil recovery chamber.