JPH08158876A - Lubricating device of supercharger - Google Patents

Abstract

PURPOSE: To more efficiently restrain leakage of lubricating oil to the side of a compressor wheel or a turbine wheel from a shaft sealing means. CONSTITUTION: A turbo charger 1 is furnished with a driving shaft 2, and a compressor wheel 7 and a turbine wheel 8 are provided on its both ends. An oil chamber 9 is formed in roughly a central part in a housing 4, and lubricating oil reserved in an oil pan 11 is supplied to the oil chamber 9 and lubricates the driving shaft 2. A seal ring 15, etc., are provided to prevent leakage of lubricating oil toward the compressor wheel 7, etc. Oil passages 21, 22 to open in the neighbourhood of both of the seal rings 15 are provided in a housing 6, and the oil passages 21, 22 are connected to a vacuum pump 27 for braking through a separating tank 25, etc. Lubricating oil to reside in the neighbourhood of the seal rings 15 is absorbed, separated into gas and liquid by the separating tank 25 and collected to the oil pan 11 by introducing negative pressure to the oil passages 21, 22 in accordance with a driving state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating device for a supercharger represented by, for example, a turbocharger for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in a turbocharger, a drive shaft is rotatably supported in a housing.
A turbine wheel and a compressor wheel are provided at each end of the drive shaft. When the turbine wheel rotates due to the pressure of the exhaust gas, the rotation is transmitted to the compressor wheel via the drive shaft, and the air is supercharged into the combustion chamber. In the turbocharger, lubricating oil is supplied to an oil chamber or the like in the housing in order to smoothly rotate the drive shaft, and the drive shaft is lubricated with the lubricating oil.

Incidentally, when a negative pressure is generated in the intake passage or the exhaust passage, a part of this lubricating oil may be sucked by the negative pressure and leak to the compressor wheel or turbine wheel side. For this reason, in the conventional turbocharger, a shaft seal means such as a seal ring is provided at the boundary between the oil chamber and the turbine wheel or compressor wheel. Further, the lubricating oil in the oil chamber is dropped by its own weight so as to be collected in the oil pan.

In order to more positively collect the lubricating oil in the oil chamber, various techniques for sucking and recovering the lubricating oil in the oil chamber using a pump have been proposed. Among such technologies,
For example, in Japanese Utility Model Publication No. 61-123809,
A return oil passage from the oil chamber of the supercharger to the oil pan is connected to the vicinity of the suction port of the oil pump for supplying the lubricating oil.
In such a configuration, by operating the oil pump, the lubricating oil is supplied from the oil pump to the oil chamber of the supercharger, and the lubricating oil is sucked from the return oil passage from the oil chamber. Then, the sucked lubricating oil is forcibly collected and used again for lubrication.

[0005]

However, in the above-mentioned prior art, the lubricating oil in the oil chamber can be more forcibly recovered, but the lubricating oil remaining in the vicinity of the seal ring can be reliably and It was difficult to recover it completely.
Therefore, it may be difficult to completely prevent the lubricating oil from leaking to the compressor wheel or turbine wheel side.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to prevent leakage of lubricating oil from the shaft sealing means to the compressor wheel or turbine wheel side more effectively. To provide a lubricator for a feeder.

[0007]

In order to achieve the above object, according to the invention as set forth in claim 1, a drive shaft rotatably supported in a housing and one end of the drive shaft are provided. A compressor wheel, and a turbine wheel provided at the other end of the drive shaft,
In order to smooth the rotation of the drive shaft, a lubricating mechanism that supplies lubricating oil to the oil chamber of the housing and collects the lubricating oil in the oil chamber into an oil pan, and the lubricating oil in the oil chamber is the compressor wheel. And a lubrication device for a supercharger for an internal combustion engine, comprising: a shaft seal means for restricting leakage toward the turbine wheel; provided in at least the housing in order to recover lubricating oil near the shaft seal means. The gist of the invention is to provide an oil passage and a suction means that is connected to the oil passage and that sucks the lubricating oil near the shaft seal means.

Further, according to the invention of claim 2, in the lubricating device for the supercharger of claim 1, wherein a braking vacuum pump is used as the suction means, it is provided in the middle of the oil passage. , A separation tank for separating the lubricating oil and the gas, a switching means for switching the braking vacuum pump also as a lubricating oil recovery pump of the supercharger by switching itself, and detecting the operating state of the internal combustion engine The gist of the invention is to provide an operating state detecting means for performing the operation, and a control means for controlling the switching means according to the operating state detected by the operating state detecting means.

[0009]

According to the invention described in claim 1, the drive shaft is rotatably supported in the housing, and when the turbine wheel at the other end of the drive shaft rotates due to the pressure of the exhaust gas, the rotation causes the drive shaft to rotate. Is transmitted to the compressor wheel via the compressor wheel and supercharges air into the combustion chamber of the internal combustion engine.

In such a supercharger, by supplying the lubricating oil into the oil chamber of the housing by the lubricating mechanism,
The drive shaft is smoothly rotated, and the lubricating oil in the oil chamber is collected in the oil pan. Further, the shaft seal means prevents the lubricating oil in the oil chamber from leaking toward the compressor wheel and the turbine wheel.

In the present invention, since the oil passage is provided at least in the housing, the lubricating oil near the shaft seal means can be collected through the oil passage. That is, the lubricating oil staying in the vicinity of the shaft sealing means is sucked by the suction means connected to the oil passage, flows through the oil passage, and is collected. Therefore, even if a differential pressure is generated between the oil chamber and the compressor wheel or turbine wheel, the lubricating oil is suppressed from leaking from the shaft sealing means toward the compressor wheel or turbine wheel.
Further, the suction means to be used need only have a relatively small capacity such that the lubricating oil accumulated near the shaft seal means can be sucked.

Further, according to the invention of claim 2,
In addition to the operation of the invention described in claim 1, the suction tank can be separated from the sucked lubricating oil by the separation tank provided in the middle of the oil passage. Therefore, suction of the lubricating oil by the braking vacuum pump can be suppressed as much as possible.

At the same time, the operating state detecting means detects the operating state of the internal combustion engine, and the control means controls the switching means in accordance with the detected operating state. The switching means is appropriately switched by this control, and the braking vacuum pump also functions as a lubricating oil recovery pump of the supercharger. As described above, by using the braking vacuum pump as the suction means in accordance with the operating state, the pump is also used, and it is not necessary to install new suction means.

[0014]

【Example】

(First Embodiment) A first embodiment of a turbocharger used in an internal combustion engine (diesel engine) in which the lubricating device for a supercharger according to the present invention is embodied will be described below with reference to FIGS.
It will be described in detail based on.

FIG. 1 is a schematic configuration diagram showing a lubricating device of a turbocharger 1 as a supercharger mounted on a vehicle in this embodiment, and FIG. 2 is a sectional view showing the turbocharger 1. As shown in these drawings, the turbocharger 1 includes a drive shaft 2, and the drive shaft 2 includes a housing 6 through a floating bearing 3, a thrust bearing 4, a thrust collar 5, and the like.
It is provided so as to be rotatably supported therein.
A compressor wheel 7 and a turbine wheel 8 are provided at one end and the other end of the drive shaft 2, respectively. Then, due to the pressure of the exhaust gas, the turbine wheel 8
When the engine rotates, the rotation is transmitted to the compressor wheel 7 via the drive shaft 2, and the air is supercharged into the combustion chamber of the diesel engine.

An oil chamber 9 is formed substantially in the center of the housing 4, and a lubricating mechanism for supplying lubricating oil to the oil chamber 9 is provided. As one of the lubrication mechanisms, an oil pump (not shown) is provided, and the oil pan 11
The lubricating oil stored in is supplied to the oil chamber 9 by the operation of an oil pump. The drive shaft 2 is lubricated by this lubricating oil. That is, the lubricating oil flows from the oil chamber 9 to the floating bearing 3, the thrust bearing 4 and the thrust collar 5 through an oil supply passage formed in the housing 6. With such a configuration, the drive shaft 2 is smoothly rotated.

On the other hand, in this embodiment, a mechanism is provided for preventing the lubricating oil from leaking toward the compressor wheel 7 and the turbine wheel 8. That is, as shown in FIGS. 2 and 3, the collar 12 is externally fitted and fixed to both ends of the drive shaft 2. Plural flanges 13 are integrally formed on the collars 12, and two grooves 14 are formed between the flanges 13. Then, these grooves 14 are provided with a metal seal ring 15 which constitutes a main shaft seal means. Basically, with the seal ring 15,
The seal ring 15 and the housing 6 (retainer) are sealed, and the housing 6 and the collar 12 are sealed. Further, a disk-shaped deflector 16, a flange-shaped slinger 17 and the like are provided on the compressor wheel 7 side as a constituent of a subordinate shaft sealing means. In this embodiment, these shaft sealing means prevent the lubricating oil from leaking toward the compressor wheel 7 and the turbine wheel 8.

Next, a characteristic part of this embodiment will be described. As shown in FIGS. 1 to 3, the housing 6 includes:
Oil passages 21 and 22 are provided for collecting the lubricating oil that can stay in the vicinity of both shaft sealing means. More specifically, the oil passages 21 and 22 are formed in openings corresponding to the flange 13 portion located between the two seal rings 15. These oil passages 21 and 22 are connected to the separation tank 25 via oil pipes 23 and 24, respectively. Further, one end of a negative pressure pipe 26 is connected to the port 25a located above the separation tank 25, and the other end of the negative pressure pipe 26 is connected to a vacuum pump 27 as a suction means. This vacuum pump 27
Is originally provided for braking the vehicle.

Further, an orifice 28 is formed in the middle of the negative pressure pipe 26, and an electromagnetic switching valve 29 constituting switching means is provided on the downstream side (vacuum pump 27 side) thereof. . This electromagnetic switching valve 29
Is an electronic control unit (hereinafter referred to as "ECU") described later.
It is controlled by an on / off switching by 41, and is opened when it is turned on and closed when it is turned off. That is, when the electromagnetic switching valve 29 is turned on, the negative pressure from the vacuum pump 27 causes the negative pressure pipe 26, the separation tank 25 and the oil pipe 23,
It is led to the oil passages 21 and 22 via 24. on the other hand,
When the electromagnetic switching valve 29 is turned off, the negative pressure from the vacuum pump 27 is not introduced, and the vacuum pump 27
Acts only as a pump for the brakes.

However, a baffle 25b is formed at the upper part of the separation tank 25 so as to partly partition the inside of the tank 25. A recovery pipe 31 is provided below the separation tank 25, and the lubricating oil stored in the separation tank 25 is guided to the oil pan 11 through the recovery pipe 31. In the present embodiment, the oil passages 21 and 22, the oil pipes 23 and 24, the recovery pipe 31, and the like constitute an oil passage as the concept of the invention. Further, a check valve 32 is provided in the middle of the recovery pipe 31. This check valve 32
When the internal pressure of the separation tank 25 becomes negative, it is closed, and when it becomes positive, it is opened.

In a diesel engine or the like, an air flow meter, an intake air temperature sensor,
Various sensors such as a throttle sensor, a water temperature sensor, an oxygen sensor, a rotation speed sensor, a crank angle sensor, and a vacuum sensor are provided. In the present embodiment, these various sensors constitute the operating state detecting means. The air flow meter is an air flow meter that measures the amount of air taken in by the engine, and the intake air temperature sensor is installed in the air flow meter and the temperature of the intake air flowing through the intake passage is changed based on the change in the resistance value of the built-in thermistor. Detect changes (intake air temperature). The throttle sensor is attached to the throttle body in the middle of the intake passage to detect the opening of the throttle valve. Further, the water temperature sensor is attached to the water outlet section to detect the temperature of the cooling water of the engine. In addition, the oxygen sensor is attached to the exhaust manifold and detects the oxygen concentration in the exhaust gas. Further, both the rotation speed sensor and the crank angle sensor are built in the distributor. The rotation speed sensor detects the engine rotation speed, and the crank angle sensor outputs a crank angle signal.
Further, the vacuum sensor is the vacuum pump 2
7, which detects the negative pressure in the pump 27.

As shown in FIG. 1, various sensors such as the air flow meter are electrically connected to the input side of the ECU 41. In addition, the vacuum pump 2
7 and the electromagnetic switching valve 29 are electrically connected to the output side of the ECU 41.

The ECU 41 constitutes a control means,
Central processing unit (CPU), read-only memory (RO
M), a random access memory (RAM), a backup RAM, an external input circuit and an external output circuit, which are connected to each other by a bus (none of which is shown). The CPU executes various arithmetic processes according to a preset control program, and the ROM stores in advance control programs and initial data necessary for the CPU to execute the arithmetic processes. Further, the RAM temporarily stores the calculation result of the CPU, and the backup RAM is backed up by a battery so as to retain various data even after the power is turned off. The external input circuit has an A / D converter (analog / digital converter).
It converts analog signals such as the intake temperature signal from the intake temperature sensor into digital signals.

Next, the operation and effect of the lubricating device for the turbocharger 1 constructed as described above will be described. According to the above-described embodiment, the lubricating oil is pumped into the oil chamber 9 of the housing 6 by the oil pump, and the lubricating oil lubricates the drive shaft 2. That is, a part of the lubricating oil lubricates the floating bearing 3, the thrust bearing 4, the thrust collar 5, etc., so that the drive shaft 2 can be smoothly rotated. In addition, the lubricating oil that has stayed in the oil chamber 9 and has been partially lubricated drops through the main passage (not shown) toward the oil pan 11 by its own weight,
Be recovered.

Further, the lubricating oil in the oil chamber 9 is transferred to the compressor wheel 7 by the shaft sealing means such as the seal ring 15.
Basically, the leakage toward the turbine wheel 8 is suppressed. Here, in this embodiment, the housing 6 is provided with oil passages 21 and 22, and these are the seal rings 15.
It opens corresponding to the portion of the flange 13 located between them. Further, a negative pressure can be appropriately introduced into these oil passages 21 and 22. Therefore, the lubricating oil staying in the vicinity of the seal ring 15 is guided to the separation tank 25 through these oil passages 21 and 22.

The above operation will be described in more detail together with the processing operation of the ECU 41. First, the ECU 41
The present operating state is read based on the detection results from various sensors, and the present operating state is recognized based on each signal. Further, the ECU 41 determines whether or not the current operating state is an operating state in which it is necessary to collect the accumulated lubricating oil. That is, it is determined whether or not the vehicle is currently in an idling state, is traveling at a high speed, or is accelerating. In any of these states, there is a high probability that the pressure on the compressor wheel 7 or turbine wheel 8 side will be higher than the pressure inside the housing 6.

When the ECU 41 determines that the predetermined operating condition is met, it outputs a signal to turn on the electromagnetic switching valve 29, and the electromagnetic switching valve 29 is opened. Then, the lubricating oil that can stay in the vicinity of the seal ring 15 is discharged from the oil passages 21 and 22 to the oil pipes 23 and 2.
4 is positively sucked toward the separation tank 25.
Since not only the lubricating oil but also a gas such as air is contained in the oil passages 21 and 22, a mixture of the lubricating oil and the gas is introduced into the separation tank 25. Then, in the separation tank 25, the lubricating oil is stored in the tank 2 due to its own gravity.
5 is stored in the lower part. Further, the gas is sucked from the port 25a toward the vacuum pump 27 through the negative pressure pipe 26. The baffle 25b in the separation tank 25
By the presence of, the lubricating oil and gas are more reliably separated,
It is possible to prevent a large amount of lubricating oil from flowing into the vacuum pump 27. Thus, when in a predetermined operating state, the vacuum pump 27 also functions as a lubricating oil recovery pump of the turbocharger 1.

When the ECU 41 determines that the predetermined operating conditions are not present, the ECU 41 outputs a signal to turn off the electromagnetic switching valve 29 on the assumption that there is almost no possibility of lubricating oil leakage, and thereby the electromagnetic switching valve 29 is turned off. The switching valve 29 is closed.
Therefore, in such a case, the vacuum pump 27
It only functions as a pump for braking. Further, in this case, the check valve 32, which has been closed by the negative pressure in the separation tank 25 until then, is opened. Therefore, the lubricating oil stored in the separation tank 25 passes through the recovery pipe 31 and drops toward the oil pan 1.

As described above, according to the present embodiment,
At least the oil passages 21 and 22 for collecting the lubricating oil that can stay near the shaft seal means are provided in the housing 6,
A negative pressure was introduced into the oil passages 21 and 22 to suck the lubricating oil. Therefore, it is possible to efficiently collect the lubricating oil that can stay at the site. As a result, even if a pressure difference occurs between the oil chamber 9 and the compressor wheel 7 or the turbine wheel 8, it is possible to more effectively prevent the lubricating oil from leaking from the shaft sealing means to the compressor wheel 7 or the turbine wheel 8 side. can do.

Further, the suction means (vacuum pump 27) used in this embodiment need only have a relatively small capacity for sucking the lubricating oil accumulated in the vicinity of the shaft sealing means. As a result, cost reduction and space saving can be achieved. Further, in the present embodiment, the vacuum pump 27 for the brake is adopted as the suction means, and the pump 27 can simultaneously achieve the two purposes of braking and lubricating oil recovery. for that reason,
It is possible to achieve more reliable cost reduction and space saving without causing a significant design change or capital investment.

Further, according to this embodiment, the separation tank 2
By providing No. 5, the sucked lubricating oil and the gas can be separated. Therefore, the vacuum pump 27
It is possible to more reliably avoid the situation where a large amount of lubricating oil is sucked.

In addition, in this embodiment, the electromagnetic switching valve 29 is controlled according to the operating state of the engine or the like to switch the introduction of negative pressure. Therefore, the vacuum pump 27 can function as a lubricating oil recovery pump as long as the braking ability is not hindered. As a result, the vacuum pump 27 can be smoothly used for two purposes depending on the operating state.

In addition, in this embodiment, the oil passages 21 and 22 are formed between the two seal rings 15. For this reason, since the lubricating oil is first dammed by the seal ring 15 on the oil chamber 9 side, a large amount of lubricating oil is generated.
It is possible to prevent the invasion of 1, 2 in advance.
As a result, it is possible to prevent the vacuum pump 27 and the like from being damaged by the lubricating oil.

(Second Embodiment) Next, a second embodiment in which the lubricating device for a supercharger according to the present invention is also embodied as a turbocharger will be described in detail with reference to FIG. However, in the configuration and the like of the present embodiment, there are many portions that overlap with the above-described first embodiment, so the same members and the like will be assigned the same reference numerals and explanations thereof will be omitted. Then, the difference from the first embodiment will be mainly described below.

As shown in FIG. 4, in the present embodiment, the electromagnetic switching valves 51 and 5 are provided in the middle of the oil pipes 23 and 24, respectively.
2 is greatly different from the first embodiment. Then, the vacuum pump 27 and the electromagnetic switching valve 2
In this embodiment, not only the electromagnetic switching valves 51 and 52 but also the electromagnetic switching valves 51 and 52 are electrically connected to the output side of the ECU 41.

Next, the function and effect unique to this embodiment will be described. The ECU 41 reads the current operating state based on the detection results from various sensors and recognizes the current operating state based on each signal. Further, the ECU 41 determines whether or not the current operating state is an operating state in which it is necessary to collect the retained lubricating oil. However, at this time, which accumulated lubricating oil needs to be collected in the vicinity of the seal ring 15 on the compressor wheel 7 side and in the vicinity of the seal ring 15 on the turbine wheel 8 side is individually determined.

When the ECU 41 determines that the predetermined operating conditions are currently set, the ECU 41 outputs a signal to turn on the electromagnetic switching valve 29. At the same time, a signal for turning on the electromagnetic switching valve 51 or 52 for which the accumulated lubricating oil needs to be collected is output according to the operating state at that time (of course, both may be turned on. Good). As a result, the electromagnetic switching valve 29 and either one of the electromagnetic switching valves 51
Or 52 is opened. Then, the lubricating oil that can stay in the vicinity of any of the seal rings 15 is sucked from the oil passages 21 and 22 to the separation tank 25 through the oil pipes 23 and 24, and the same operational effect as described above is achieved.

When the ECU 41 determines that the predetermined operating conditions are not present, all the electromagnetic switching valves 29, 51, 52 are considered to have little risk of lubricating oil leakage.
Is output, and the electromagnetic switching valves 29, 51, 52 are closed. Therefore, in such a case, the vacuum pump 27 exerts only the function as a pump for braking. In this case, the first
As in the embodiment, the check valve 32 is opened and the separation tank 2
The lubricating oil stored in 5 passes through the recovery pipe 31 and falls toward the oil pan 1.

As described above, according to this embodiment, in addition to the effects of the first embodiment, the operating conditions at that time are the vicinity of the seal ring 15 on the compressor wheel 7 side and the seal ring on the turbine wheel 8 side. It was determined which of the 15 retained oils needed to be collected. Then, based on the result of the determination, an opportunity is provided to open the electromagnetic switching valve 51 or 52 for only one of them, and the lubricating oil on the required side is collected.
Therefore, the lubricating oil can be collected in a timely manner only when necessary. Further, even if the magnitude of the negative pressure introduced from the vacuum pump 27 is small as a whole, sufficient recovery can be achieved. as a result,
The vacuum pump 27 can be downsized, the output can be reduced, and the cost can be further reduced.

The present invention is not limited to the above embodiment, but may be configured as follows, for example. (1) In each of the above embodiments, the oil passages 21 and 22 provided in the housing 6 are configured to open corresponding to the flange 13 portion located between the two seal rings 15, but the seal ring 15 Any portion 4 may be opened as long as it is in the vicinity of the shaft sealing means such as, for example, it can be configured as follows.

(1-a) As shown in FIG. 5, it is possible to form a through hole 62 in the seal ring 61 and to provide an oil passage 63 so as to face the through hole 62. In such a case, the seal ring 61 may be provided only at one place.

(1-b) As shown in FIG. 6, the collar 71
A plurality of fins 73 are provided on the oil chamber 9 side of the seal ring 72 on the circumference of the
An oil passage 74 may be provided between the No. 3 and the seal ring 72. In such a case, as the drive shaft 2 rotates, the lubricating oil is blown to the oil chamber 9 side by the fins 73, and it is difficult for the lubricating oil to flow to the right side of the drawing, that is, the seal ring 72 side. Therefore, as in the first and second embodiments, it is possible to prevent a large amount of lubricating oil from entering the oil passage 74.

(2) In the above embodiment, the suction means is
Although the structure which doubles as the vacuum pump 27 for braking is adopted, there is no problem even if a separate suction means such as a pump is provided.

(3) In the above-described embodiment, the lubricating oil in the oil chamber 9 is dropped into the oil pan 11 by its own weight drop. However, as described in the prior art, it is sucked by a separate pump or the like. May be

(4) In the above embodiment, the turbocharger 1 for a diesel engine is embodied, but it may be embodied for a gasoline engine. The technical idea which is not described in each claim of the claims and which can be grasped from the above-described embodiment will be described below together with its effect.

(A) In the lubrication device for a supercharger according to claim 1 or 2, the oil passage is provided on the compressor wheel or turbine wheel side (outer side) of at least some shaft sealing means. Is characterized by. With such a configuration, it is possible to prevent a large amount of lubricating oil from entering the oil passage.

[0047]

As described above in detail, according to the lubricating device for a supercharger of the present invention, it is possible to more effectively suppress the leakage of lubricating oil from the shaft sealing means to the compressor wheel or turbine wheel side. It has an excellent effect that it can be done.

Further, in particular, according to the invention described in claim 2, it is possible to significantly reduce the cost and save the space.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a lubricating device for a turbocharger according to a first embodiment.

FIG. 2 is a sectional view showing a turbocharger of the first embodiment.

FIG. 3 is an enlarged sectional view showing a main part of the turbocharger of the first embodiment.

FIG. 4 is a configuration diagram showing a lubricating device for a turbocharger according to a second embodiment.

FIG. 5 is an enlarged cross-sectional view showing a main part of a turbocharger in another example.

FIG. 6 is an enlarged cross-sectional view showing a main part of a turbocharger in another example.

[Explanation of symbols]

1 ... Turbocharger as supercharger, 2 ... Drive shaft, 6 ... Housing, 7 ... Compressor wheel, 8 ...
Turbine wheel, 9 ... Oil chamber, 11 ... Oil pan, 1
5, 63, 74 ... Seal rings constituting main shaft sealing means, 21, 22, 63, 74 ... Oil passage, 25 ... Separation tank, 27 ... Vacuum pump as suction means, 2
9, 51, 52 ... Electromagnetic switching valve constituting switching means, 41
... ECU that constitutes the control means.

Claims (2)

[Claims] 1. A drive shaft rotatably supported in a housing, a compressor wheel provided at one end of the drive shaft, a turbine wheel provided at the other end of the drive shaft, and a drive shaft for the drive shaft. In order to smooth the rotation, a lubricating mechanism that supplies lubricating oil into the oil chamber of the housing and collects the lubricating oil in the oil chamber into an oil pan, and the lubricating oil in the oil chamber is A lubrication device for a supercharger for an internal combustion engine, comprising: a shaft seal means for restricting leakage toward one side; an oil passage provided at least in the housing for recovering lubricating oil near the shaft seal means. And a suction means connected to the oil passage for sucking the lubricating oil near the shaft seal means. Lubricator for supercharger. 2. The lubricating device for a supercharger according to claim 1, wherein a braking vacuum pump is used as the suction means, the lubricating device being provided in the middle of the oil passage for separating lubricating oil and gas. A separation tank; a switching means that causes the braking vacuum pump to function also as a lubricating oil recovery pump of a supercharger by switching itself; an operating state detecting means for detecting an operating state of an internal combustion engine; A lubrication device for a supercharger, comprising: a control unit that controls the switching unit according to an operating state detected by a state detection unit.