JP4480616B2 - Oil tank - Google Patents

Description

  The present invention relates to an oil tank used in a lubrication device for a dry sump type internal combustion engine.

  An oil tank is known which has a centrifugal separator at the top of the tank and has radial vertical baffles and a horizontal baffle on the disc below the separator to separate lubricating oil and air (Patent Literature). 1). In addition, there are Patent Documents 2 to 4 as prior art documents related to the present invention.

Japanese Patent Laid-Open No. 3-96610 JP 2003-210908 A JP-A-8-187403 JP 2003-144842 A

  When gas that cannot be separated by gas-liquid separation means such as a separator is discharged from the gas-liquid separation means together with the lubricating oil, large bubbles may be formed. This large bubble bursts with a loud sound on the surface of the lubricating oil stored in the oil tank, which causes noise.

  Then, an object of this invention is to provide the oil tank which can suppress a noise.

The first oil tank of the present invention is used in a lubrication device for a dry sump type internal combustion engine, is provided separately from the engine main body of the internal combustion engine, and has a gas-liquid separating action on the lubricating oil returned from the engine main body. In the oil tank having gas-liquid separation means for discharging the obtained bubbles from the gas discharge port and discharging the remaining lubricating oil from the liquid discharge port, the liquid discharge port is stored in the oil tank. Disposed in the lubricating oil, the liquid discharge port is provided with bubble fragmentation means for fragmenting bubbles, and a propeller is used as the bubble fragmentation means, thereby solving the above-mentioned problems (claims) Item 1).

According to the oil tank of the present invention, even if bubbles are contained in the remaining lubricating oil discharged from the liquid discharge port of the gas-liquid separating means, the bubbles are subdivided by the bubble subdividing means. The generated sound can be reduced. Therefore, noise generated from the oil tank can be suppressed. Further, since the bubbles can be divided by the propeller, the bubbles can be subdivided.

The second oil tank of the present invention is used in a lubrication device for a dry sump type internal combustion engine, and is provided separately from the engine body of the internal combustion engine, and gas-liquid separation action is applied to the lubricating oil returned from the engine body. In the oil tank having gas-liquid separation means for discharging the obtained bubbles from the gas discharge port and discharging the remaining lubricating oil from the liquid discharge port, the liquid discharge port is stored in the oil tank. Disposed in the lubricating oil, the liquid outlet is provided with bubble fragmentation means for subdividing the bubbles, and as the bubble fragmentation means, the flow of the remaining lubricating oil discharged from the liquid outlet is traversed. optionally used is a net which is arranged in a direction (claim 2). According to the second oil tank of the present invention, the bubbles are subdivided by the bubble subdividing means even if bubbles are contained in the remaining lubricating oil discharged from the liquid discharge port of the gas-liquid separating means. The sound generated at the time of bursting can be reduced. Therefore, noise generated from the oil tank can be suppressed. Further , even if bubbles are contained in the remaining lubricating oil discharged from the liquid discharge port, the bubbles can be subdivided by the net.

The third oil tank of the present invention is used in a lubrication device for a dry sump type internal combustion engine, is provided separately from the engine main body of the internal combustion engine, and has a gas-liquid separating action on the lubricating oil returned from the engine main body. In the oil tank having gas-liquid separation means for discharging the obtained bubbles from the gas discharge port and discharging the remaining lubricating oil from the liquid discharge port, the liquid discharge port is stored in the oil tank. Disposed in the lubricating oil, the liquid discharge port is provided with bubble fragmentation means for subdividing bubbles, the oil tank is provided with a take-out port for taking out the lubricating oil sent to the engine body, and As the bubble fragmentation means, a bubble dispersion container in which an upper surface and a lower surface are formed by flat plates and a side surface is formed by a flat plate having a plurality of through holes having a diameter smaller than that of the liquid discharge port is provided. And outlet facing and the side surface may be disposed so as to face the liquid outlet (Claim 3). According to the third oil tank of the present invention, the bubbles are subdivided by the bubble subdividing means even if bubbles are contained in the remaining lubricating oil discharged from the liquid discharge port of the gas-liquid separating means. The sound generated at the time of bursting can be reduced. Therefore, noise generated from the oil tank can be suppressed. Further , even if bubbles are included in the remaining lubricating oil discharged from the liquid discharge port, the bubbles can be subdivided by the plurality of through holes on the side surface. Further, since the lower surface of the bubble dispersion container is formed of a flat plate, the bubbles are not discharged below the bubble dispersion container. Furthermore, since the bubble dispersion container is provided so that the lower surface faces the take-out port, it is possible to suppress discharge of bubbles from the take-out port. Therefore, it is possible to suppress air bubbles from being mixed into the lubricating oil sent to the engine body.

The fourth oil tank of the present invention is used in a lubrication device for a dry sump type internal combustion engine, and is provided separately from the engine body of the internal combustion engine, and gas-liquid separation action is applied to the lubricating oil returned from the engine body. In the oil tank having gas-liquid separation means for discharging the obtained bubbles from the gas discharge port and discharging the remaining lubricating oil from the liquid discharge port, the liquid discharge port is stored in the oil tank. Disposed in the lubricating oil, the liquid discharge port is provided with bubble fragmentation means for subdividing bubbles, and as the bubble fragmentation means, an upper surface and a lower surface are formed of a flat plate and have a diameter larger than that of the liquid discharge port. A cylindrical bubble dispersion container having a side surface formed of a flat plate having a plurality of through-holes is used, and the bubble dispersion container introduces residual lubricating oil discharged from the liquid discharge port therein mouth Wherein together with the side surface, the remainder of the lubricating oil introduced from the introduction port may be arranged to pivot in the interior of the bubble dispersion container (claim 4). According to the fourth oil tank of the present invention, the bubbles are subdivided by the bubble subdividing means even if bubbles are contained in the remaining lubricating oil discharged from the liquid discharge port of the gas-liquid separating means. The sound generated at the time of bursting can be reduced. Therefore, noise generated from the oil tank can be suppressed. Further , the remaining lubricating oil discharged from the liquid discharge port in the gas-liquid separation container can be swirled, and the remaining lubricating oil can be separated again using centrifugal force. At this time, since the obtained bubbles pass through a plurality of through holes provided on the side surface and are discharged to the outside of the bubble dispersion container, the bubbles can be subdivided.

  As described above, according to the present invention, even if bubbles are contained in the remaining lubricating oil discharged from the liquid discharge port into the lubricating oil stored in the oil tank, the bubbles are subdivided into bubbles. Since it can be subdivided by means, it is possible to suppress the sound generated when the bubbles burst. Therefore, noise generated from the oil tank can be suppressed.

4 to 7 show an embodiment of the present invention. First, a reference example having a common part with them will be described with reference to FIGS. 1 to 3 (a) and 3 (b). FIG. 1 shows an overall configuration of an embodiment in which a lubricating device using an oil tank according to the present invention is incorporated in an internal combustion engine for a vehicle. The lubrication apparatus 1 is a so-called dry sump system, and is provided in an internal combustion engine 100 for a vehicle. An intake passage 102 is connected to the engine body 101 of the internal combustion engine 100, and a throttle valve 103 is provided in the intake passage 102. The lubrication apparatus 1 is discharged by a feed pump 2 that supplies lubricating oil to each part of the engine body 101, a scavenge pump 3 that discharges the lubricating oil returned to the oil pan 104 of the engine body 101, and the scavenge pump 3. And an oil tank 4 through which the lubricating oil is guided. Lubricating oil in the oil tank 4 is supplied to each part of the engine main body 101 via the supply passage 5 by the feed pump 2. The lubricating oil that has lubricated each part of the engine body 101 is collected in the oil pan 104 and then returned from the oil pan 104 to the oil tank 4 via the discharge passage 6 by the scavenge pump 3. Thus, the lubricating oil circulates between the oil tank 4 and the engine body 101.

  The scavenge pump 3 guides a gas such as blow-by gas to the oil tank 4 together with the lubricating oil collected in the oil pan 104. Therefore, a PCV passage 7 that guides a gas such as blow-by gas accumulated in the oil tank 4 to the intake passage 102 is connected to the upper portion of the oil tank 4. The oil tank 4 is substantially closed to the outside except for the supply passage 5, the discharge passage 6, and the PCV passage 7 connected to the oil tank 4 so that blow-by gas does not leak out from the oil tank 4. ing. The PCV passage 7 has a main passage 71 and a sub-passage 72. As shown in FIG. 1, the main passage 71 connects the oil tank 4 and the intake passage 102 on the downstream side of the throttle valve 103. The auxiliary passage 72 connects the oil tank 4 and the intake passage 102 upstream of the throttle valve 103. The sub-passage 72 is provided with a check valve 73 that opens when a preset set pressure is exceeded. Therefore, when the pressure in the oil tank 4 exceeds the set pressure, gas such as blow-by gas in the oil tank 4 is guided to the intake passage 102 through the main passage 71 and the sub passage 72, respectively. The internal combustion engine 100 is provided with a communication passage 105 that connects the intake passage 102 upstream of the throttle valve 102 and the oil pan 104, and fresh air is introduced into the oil pan 104 through the communication passage 105. be introduced.

  As shown in FIG. 1, the oil tank 4 is a gas-liquid separator for separating gas such as blow-by gas from lubricating oil (hereinafter referred to as return lubricating oil) returned from the engine body 101 to the oil tank 4. 8 is provided. The gas-liquid separator 8 uses centrifugal force to separate the gas from the return lubricating oil. As shown by the arrow A, the return lubricating oil is guided to the inside from the lubricating oil inlet 8a provided on the upper side surface. The return lubricant is swirled inside and centrifuged to obtain bubbles from the return lubricant. In this way, the gas-liquid separator 8 gives a gas-liquid separation action to the return lubricating oil. The obtained bubbles are discharged from the gas discharge port 8 c and guided to the gas layer portion of the oil tank 4. On the other hand, the remaining lubricating oil (hereinafter abbreviated as “residual lubricating oil”) after the bubbles are separated by centrifugal separation is discharged into the oil tank 4 from the liquid discharge port 8b provided on the lower side surface. As shown in FIG. 1, the liquid discharge port 8 b is provided below the level L of the lubricating oil stored in the oil tank 4, that is, in the lubricating oil stored in the oil tank 4. . Therefore, the remaining lubricating oil discharged from the liquid discharge port 8b is discharged into the lubricating oil stored in the oil tank 4.

  FIG. 2 shows an enlarged view of the gas-liquid separator 8 of FIG. As shown in FIG. 2 (a), the liquid discharge port 8b of the gas-liquid separator 8 is provided with a bubble dispersion portion 9 as bubble fragmentation means. The bubble dispersing portion 9 has a bottomed cylindrical shape, and as shown in FIG. 2A, a plurality of through holes 9a smaller than the diameter of the liquid discharge port 8b are provided on the side surface and the bottom portion, respectively. It has been. The residual lubricating oil discharged from the gas-liquid separator 8 passes through the plurality of through holes 9a and is returned to the oil tank 4. Note that the number and diameter of the plurality of through holes 9 a are appropriately set according to, for example, the amount of lubricating oil circulated by the lubricating device 1 during operation of the internal combustion engine 100. For example, in the case where bubbles are included in the residual lubricating oil so as not to prevent the residual lubricating oil from being discharged from the liquid discharge port 8b by the bubble dispersing portion 9 and guiding the lubricating oil to the gas discharging port 8c. The number and diameter of the plurality of through holes 9a are set so that the bubbles are sufficiently subdivided.

  When the flow velocity of the return lubricant in the gas-liquid separator 8 is too high or the amount of return lubricant is large, the gas-liquid separator 8 does not sufficiently separate the bubbles from the return lubricant, and the liquid discharge port 8b Bubbles are discharged into the oil tank 4 together with the remaining lubricating oil. FIG. 2B shows a state of bubbles discharged from the liquid discharge port 8b of the gas-liquid separator 8 of FIG. As shown in FIG. 2B, the bubbles discharged from the liquid discharge port 8 b are subdivided by passing through the plurality of through holes 9 a of the bubble dispersion portion 9. Therefore, at the liquid level L in the oil tank 4, the subdivided bubbles burst.

  As a comparative example, the state of bubbles discharged from the liquid discharge port 8b of the gas-liquid separator 8 shown in FIG. As shown in FIG. 3 (b), in the gas-liquid separator 8 of FIG. 3 (a), the bubbles discharged from the liquid discharge port 8b burst at the liquid level L without being subdivided. appear. Further, as shown in FIG. 3B, the lubricating oil is scattered in the oil tank 4 when the bubbles burst.

As described above, according to this reference example , even if the bubbles are discharged together with the remaining lubricating oil from the liquid discharge port 8b of the gas-liquid separator 8, the bubbles are subdivided, and thus generated when the bubbles burst. Abnormal noise can be suppressed. Further, since the bubbles are subdivided, scattering of the lubricating oil when the bubbles burst can be suppressed. Note that the plurality of through holes 9a of the bubble dispersion portion 9 may be provided only on either the side surface or the bottom surface. The shape of the plurality of through holes 9a may not be a circle, and may be a slit or a polygon as long as the bubbles discharged together with the remaining lubricating oil can be subdivided.

( First embodiment)
FIG. 4 shows a main part of the oil tank according to the first embodiment of the present invention. 4A shows the gas-liquid separator 8 provided in the oil tank of this embodiment, and FIG. 4B shows the oil tank from the liquid discharge port 8b of the gas-liquid separator 8 in FIG. 4A. 4 shows the state of bubbles discharged into the interior. 4 that are the same as those in FIG. 2 described above are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 4A, the gas-liquid separator 8 of this embodiment is different from the other embodiments in that a propeller 10 is provided as a bubble subdividing means at the liquid discharge port 8b. The propeller 10 has a rotating shaft 10a arranged in parallel with the flow direction of the lubricating oil discharged from the liquid discharge port 8b, and is rotationally driven by the lubricating oil discharged from the liquid discharge port 8b. Therefore, as shown in FIG. 4B, the bubbles discharged from the liquid discharge port 8b are divided and subdivided by the propeller 10.

  As described above, in the present embodiment, since the bubbles discharged into the oil tank 4 from the liquid discharge port 8b of the gas-liquid separator 8 are subdivided by the propeller 10, the bubbles burst at the liquid level L. Abnormal noise generated sometimes can be suppressed. In addition, scattering of the lubricating oil when the bubbles burst can be suppressed.

( Second embodiment)
FIG. 5 shows a main part of an oil tank according to the second embodiment of the present invention. 5A shows the gas-liquid separator 8 provided in the oil tank of this embodiment, and FIG. 5B shows the oil tank from the liquid discharge port 8b of the gas-liquid separator 8 of FIG. 5A. 4 shows the state of bubbles discharged into the interior. 5 that are the same as those in FIG. 2 are given the same reference numerals, and descriptions thereof are omitted.

  As shown in FIG. 5 (a), in the gas-liquid separator 8 of the present embodiment, the net 11 is provided at the liquid discharge port 8b in a direction crossing the flow of the remaining lubricating oil discharged from the liquid discharge port 8b. This is different from the other embodiments. Note that the mesh size of the mesh 11, that is, the mesh size, is appropriately set according to, for example, the amount of lubricating oil that the lubricating device 1 circulates when the internal combustion engine 100 is operated. According to this gas-liquid separator 8, as shown in FIG. 5B, the bubbles discharged from the liquid discharge port 8b into the oil tank 4 by the net 11 can be subdivided. The net 11 may be provided directly at the liquid discharge port 8b, or the liquid discharge port so that the entire amount of lubricating oil discharged from the liquid discharge port 8b passes through the net 11 and is discharged into the oil tank 4. It may be fixed to the outside of 8b.

  As described above, in the present embodiment, since the bubbles discharged from the liquid discharge port 8b into the oil tank 4 are subdivided by the net 11, the noise generated when the bubbles burst is suppressed. it can. In addition, scattering of the lubricating oil when the bubbles burst can be suppressed.

( Third embodiment)
FIG. 6 shows an oil tank according to the third embodiment of the present invention. 6 that are the same as those in FIG. 2 are assigned the same reference numerals, and descriptions thereof are omitted. In the oil tank 4 of the present embodiment, a bubble dispersion container 20 is provided as bubble fragmentation means. As shown in FIG. 6, the bubble dispersion container 20 includes a flat plate in which the upper surface 21 and the lower surface 22 do not have through holes, and a plurality of side surfaces 23 that connect the upper surface 21 and the lower surface 22 have a plurality of through holes. (Hereinafter abbreviated as a perforated flat plate). For example, punched metal is used as the perforated flat plate. The diameters of the plurality of through holes are set to be smaller than the diameter of the liquid discharge port 8b. For example, the noise generated when the bubbles subdivided by the plurality of through holes burst is set to be sufficiently small. As shown in FIG. 6, the bubble dispersion container 20 includes a bubble entrainment prevention plate 24. The bubble entrainment prevention plate 24 is provided by causing a part of the lower surface 22 of the bubble dispersion container 20 to protrude from the upper surface 21.

  The bottom surface 4a of the oil tank 4 is provided with a lubricant outlet 4b. The lubricant in the oil tank 4 is extracted from the outlet 4b and supplied to each part of the engine body 101 by the feed pump 2.

  As shown in FIG. 6, the bubble dispersion container 20 is placed in the oil tank 4 so that the lower surface 22 faces the take-out port 4 b and one side of the side surface 23 faces the liquid discharge port 8 b of the gas-liquid separator 8. Be placed. In the bubble dispersion container 20 of FIG. 6, the side surface 23 provided on the side opposite to the side on which the bubble entrainment prevention plate 24 is provided faces the liquid discharge port 8b. By disposing the bubble dispersion container 20 in this way, the residual lubricating oil discharged from the liquid discharge port 8b passes through the side surface 23 facing the liquid discharge port 8b and is guided into the bubble dispersion container 20, and thereafter It passes through the side surface 23 other than the side surface 23 facing the liquid discharge port 8 b and is returned into the oil tank 4. Note that the residual lubricating oil discharged from the side surface 23 on the side where the bubble entrainment prevention plate 24 is provided is restricted by the bubble entrainment prevention plate 24 from moving downward, and is indicated by an arrow B in FIG. It is guided upward as if.

  According to the present embodiment, the bubbles discharged together with the remaining lubricating oil into the oil tank 4 from the liquid discharge port 8b of the gas-liquid separator 8 are subdivided by the side surface 23 formed by the perforated flat plate. For this reason, it is possible to suppress abnormal noise generated when the bubbles burst. Moreover, scattering of the lubricating oil at the time of bubble burst can be suppressed. Further, in this embodiment, the lower surface 22 of the bubble dispersion container 20 is opposed to the take-out port 4b, and the bubble entrainment prevention plate 24 inhibits the movement of the bubbles downward, so that the entrainment of bubbles by the lubricating oil is suppressed. it can. Therefore, it is possible to suppress air bubbles from being mixed into the lubricating oil taken out from the take-out port 4b.

  FIG. 7 shows another embodiment of the bubble dispersion container disposed in the oil tank 4. The bubble dispersion container 30 of FIG. 7 has a cylindrical shape having a space inside, and the upper surface 31 and the lower surface 32 thereof are each formed of a flat plate having no through hole, and the side surface 33 is formed of a perforated flat plate. Is done. In addition, as a perforated flat plate, punching metal etc. are used similarly to the bubble dispersion | distribution container of FIG. 6 mentioned above, for example. Further, as shown in FIG. 7, the bubble dispersion container 30 is provided with an introduction port 34 for introducing the lubricating oil discharged from the liquid discharge port 8 b of the gas-liquid separator 8 on the side surface 33.

  In the bubble dispersion container 30, the introduction port 34 provided on the side surface 33 faces the liquid discharge port 8 b of the gas-liquid separator 8, and the lubricating oil introduced from the introduction port 34 swirls within the bubble dispersion container 30. It is arranged in the oil tank 4.

  According to the bubble dispersion container 30 of FIG. 7, the residual lubricating oil discharged from the gas-liquid separator 8 is swung in the oil tank 4, so that the residual lubricating oil and gas are centrifuged again in the oil tank 4. be able to. Therefore, the separation of the gas from the remaining lubricating oil can be promoted. In addition, since the bubbles are discharged from the side surface 33 formed of the perforated flat plate, the bubbles can be subdivided and noise generated when the bubbles burst can be suppressed. Further, the oil surface can be prevented from being disturbed by generating a swirl flow in the oil tank 4.

  Note that a member for subdividing bubbles such as a perforated flat plate may be provided inside the bubble dispersion container. In this case, fragmentation of bubbles can be promoted.

The figure which shows the whole structure of embodiment which integrated the lubricating device using the oil tank which concerns on the reference example of this invention in the internal combustion engine for vehicles. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which expands and shows a part of oil tank which concerns on the reference example of this invention, (a) expands and shows a gas-liquid separator, (b) is from the discharge port of the gas-liquid separator of (a). The state of the bubble to be discharged is shown. It is a figure which shows the gas-liquid separator which does not provide a bubble dispersion | distribution part, (a) shows the enlarged view of a gas-liquid separator, (b) shows the bubble discharged | emitted from the discharge port of the gas-liquid separator of (a). Indicates the state. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which expands and shows a part of oil tank which concerns on 1st embodiment of this invention, (a) expands and shows a gas-liquid separator, (b) shows the gas-liquid separator of (a). The state of the bubbles discharged from the discharge port is shown. It is a figure which expands and shows a part of oil tank concerning a second embodiment of the present invention, (a) expands and shows a gas-liquid separator, (b) shows a gas-liquid separator of (a). The state of the bubbles discharged from the discharge port is shown. The figure which shows the oil tank which concerns on 3rd embodiment of this invention. The figure which shows the other Example of the bubble dispersion | distribution container provided in 3rd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lubrication device 4 Oil tank 4a Bottom surface 4b Outlet 8 Gas-liquid separator (gas-liquid separation means)
8b Liquid outlet 8c Gas outlet 9 Bubble dispersion part (bubble dispersion member, bubble fragmentation means)
9a Through-hole 10 propeller (bubble subdivision means)
11 Net (bubble subdivision means)
20 Bubble dispersion container (bubble fragmentation means)
21 Upper surface 22 Lower surface 23 Side surface 30 Bubble dispersion container (bubble fragmentation means)
31 Upper surface 32 Lower surface 33 Side surface 34 Inlet port 100 Internal combustion engine 101 Engine body

Claims (4)

Used in a lubrication device for a dry sump type internal combustion engine and provided separately from the engine body of the internal combustion engine, and gives a gas-liquid separation action to the lubricating oil returned from the engine body. In an oil tank equipped with gas-liquid separation means for discharging from the outlet and discharging the remaining lubricating oil from the liquid outlet,
The liquid discharge port is disposed in the lubricating oil stored in the oil tank, and the liquid discharge port is provided with bubble fragmentation means for fragmenting bubbles,
An oil tank using a propeller as the bubble subdividing means . Used in a lubrication device for a dry sump type internal combustion engine and provided separately from the engine body of the internal combustion engine, and gives a gas-liquid separation action to the lubricating oil returned from the engine body. In an oil tank equipped with gas-liquid separation means for discharging from the outlet and discharging the remaining lubricating oil from the liquid outlet,
The liquid discharge port is disposed in the lubricating oil stored in the oil tank, and the liquid discharge port is provided with bubble fragmentation means for fragmenting bubbles,
Examples bubble subdividing means, an oil tank, wherein a network is used which is arranged in a direction transverse to the flow of residual lubricating oil discharged from the liquid discharge port. Used in a lubrication device for a dry sump type internal combustion engine and provided separately from the engine body of the internal combustion engine, and gives a gas-liquid separation action to the lubricating oil returned from the engine body. In an oil tank equipped with gas-liquid separation means for discharging from the outlet and discharging the remaining lubricating oil from the liquid outlet,
The liquid discharge port is disposed in the lubricating oil stored in the oil tank, and the liquid discharge port is provided with bubble fragmentation means for fragmenting bubbles,
The bottom of the oil tank is provided with a take-out port from which the lubricating oil sent to the engine body is taken out,
As the bubble subdividing means, a bubble dispersion container in which an upper surface and a lower surface are formed by a flat plate and a side surface is formed by a flat plate having a plurality of through holes whose diameter is smaller than that of the liquid discharge port, And an oil tank arranged so that the side surface faces the liquid discharge port. Used in a lubrication device for a dry sump type internal combustion engine and provided separately from the engine body of the internal combustion engine, and gives a gas-liquid separation action to the lubricating oil returned from the engine body. In an oil tank equipped with gas-liquid separation means for discharging from the outlet and discharging the remaining lubricating oil from the liquid outlet,
The liquid discharge port is disposed in the lubricating oil stored in the oil tank, and the liquid discharge port is provided with bubble fragmentation means for fragmenting bubbles,
As the bubble fragmentation means, a cylindrical bubble dispersion container in which the upper surface and the lower surface are formed of a flat plate and the side surface is formed of a flat plate having a plurality of through holes having a diameter smaller than the liquid discharge port is used ,
The bubble dispersion container has an introduction port for introducing the remaining lubricating oil discharged from the liquid discharge port in the side surface, and the remaining lubricating oil introduced from the introduction port is contained in the bubble dispersion container. An oil tank that is arranged to swivel inside.

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