JP2007297973A - Supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supercharger capable of surely preventing oil leak from a perimeter of a thrust bearing structure to other sections even if lubricating oil supplied to the thrust bearing structure increases. <P>SOLUTION: The supercharger is provided with a turbine impeller 11 driven and rotated by exhaust gas, a compressor impeller 14 driven and rotated by rotation of the turbine impeller 11 and compressing air, a rotary shaft 12 connecting the turbine impeller 11 and the compressor impeller 14, a housing 16 storing the rotary shaft 12 inside thereof, the thrust bearing structure 30 rotatably supporting thrust force acting on the rotary shaft 12. An oil discharge path 43 discharging lubricating oil from an oil pocket space 41 of the thrust bearing structure 30 is formed in the housing 16. The oil discharge path opens to the oil pocket space 41, extends in an axial direction from the opening 41a, and extends further downward to communicate to an oil discharge port positioned at a lower part of the housing 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a supercharger.

  Supplying air whose density has been increased by the compressor to the engine is called supercharging, and among these, the one that covers the driving work of the compressor by the exhaust energy is called turbocharger.

  An exhaust turbine supercharger generally includes a compressor (compressor) and a turbine disposed with a bearing unit interposed therebetween, and the compressor incorporates a compressor impeller and the turbine incorporates a turbine impeller. The compressor impeller and the turbine impeller are connected to each other by a rotating shaft (shaft) supported by a bearing unit. The turbine impeller is rotationally driven by engine exhaust gas, and this rotational force is transmitted to the compressor impeller via the rotating shaft. The air is compressed by the compressor impeller and supercharged to the engine.

Further, such a turbocharger is provided with a thrust bearing structure that rotatably supports a thrust force acting on the rotating shaft. The thrust bearing structure is described in Patent Document 1, for example, and FIG. 6 is a cross-sectional view showing the configuration of the peripheral portion of the thrust bearing structure 60 of Patent Document 1.
The thrust bearing structure 60 includes a thrust collar 62 fixed to a rotary shaft 61, a compressor-side thrust bearing 65 positioned on the compressor side of the thrust collar 62 and fixed to a bearing housing 63, and a turbine side of the thrust collar 62. And a turbine-side thrust bearing 67 fixed to the bearing housing 63.

The compressor side thrust bearing 65 receives the axial load from the thrust collar 62 to the compressor side, with the turbine side end face coming into contact with the compressor side end face of the thrust collar 62. On the other hand, the compressor side end surface of the turbine side thrust bearing 67 is in contact with the turbine side end surface of the thrust collar 62 and receives an axial load from the thrust collar 62 to the compressor side.
Thus, the compressor-side thrust bearing 65 and the turbine-side thrust bearing 67 receive the axial load from the thrust collar 62 fixed to the rotary shaft 61, thereby supporting the rotary shaft 61 in the axial direction.

In a supercharger, since the pressure acting on the turbine impeller is generally higher than the pressure acting on the compressor impeller, a large thrust force is generated in the direction toward the compressor impeller.
In order for the compressor side thrust bearing 65 to receive this thrust force with low resistance, it is necessary to supply a sufficient amount of lubricating oil between the thrust collar 62 and the compressor side thrust bearing 65. For example, as shown in FIG. 6, the lubricating oil is supplied through a lubricating oil passage 68 formed in the bearing housing 63 and an oil passage 69 formed in the compressor-side thrust bearing 65.
The lubricating oil supplied in this way is guided to an oil outlet (not shown) provided in the lower part of the thrust bearing structure 60 in the direction of the arrow in FIG.

  However, a part of the lubricating oil supplied to the thrust bearing structure 60 may not be guided to the oil discharge port and may leak to other locations such as the compressor side. Prior arts for preventing such oil leakage are described, for example, in Patent Documents 2 and 3 below.

As shown in FIG. 7B, which is a view taken along the line B-B of FIG. 7A and FIG. 7A, the bearing device of Patent Document 2 has outer peripheries of thrust bearings 72 and 73. An oil sump space 74 is provided at a position corresponding to the above, and two oil drain passages 77 are provided on each of the left and right sides that communicate with the space 74, the bearing stand 75, and the oil drain port 76. Smooth oil drainage is performed by these two oil drain passages 77.

  Further, as shown in FIG. 8, the turbocharger disclosed in Patent Document 3 is a turbocharger having a turbine shaft 81, a radial bearing 82, a stepped portion 83, and an oil drain 84, and is stepped from the side wall surface of the radial bearing 82. The distance L to the portion 83 is a distance in which the oil moved from the end of the radial bearing 82 is not in contact with the stepped portion 83 in a region where the turbine rotational speed is larger than the turbine rotational speed during idling of the engine. It is.

Japanese Utility Model Publication No. 4-119624 "Turbocharger bearing structure" Japanese Utility Model Laid-Open No. 60-52352, “Bearing device for exhaust turbine supercharger” JP 2002-54448 A, “Exhaust Turbine Supercharger and Supercharging System for Internal Combustion Engines”

  In Patent Document 2, the lubricating oil around the thrust collar is discharged by being circulated downward through two drainage passages 77 at each of the left and right sides. However, when the amount of drainage increases, there is a possibility that the lubricant cannot be completely discharged. .

  Even in Patent Document 3, when the oil discharge amount increases, the oil may leak beyond the stepped portion 83.

  Therefore, it is desirable to prevent oil leakage more reliably by means other than the means of Patent Documents 2 and 3 or means that can be added to the means of Patent Documents 2 and 3.

  The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a supercharger that can more reliably prevent oil leakage from the periphery of the thrust bearing structure to other places even when the lubricating oil supplied to the thrust bearing structure increases. is there.

  According to the present invention, a turbine impeller that is rotationally driven by exhaust gas, a compressor impeller that is rotationally driven by the rotation of the turbine impeller and compresses air, a rotary shaft that connects the turbine impeller and the compressor impeller, and the rotary shaft And a thrust bearing structure that rotatably supports a thrust force acting on the rotating shaft, wherein the housing includes lubricating oil from an oil reservoir space of the thrust bearing structure. An oil discharge passage for discharging the oil is formed, and the oil discharge passage opens in the oil reservoir space, extends in the axial direction from the opening, further extends downward, and is located at the lower portion of the housing. A turbocharger is provided which is characterized in that it leads to

According to the above configuration, the oil discharge passage for discharging the lubricating oil from the oil reservoir space of the thrust bearing structure opens into the oil reservoir space, extends in the axial direction from the opening, further extends downward, and is formed in the lower portion of the housing. As the lubricating oil accumulates in the oil sump space, the lubricating oil in the oil sump space enters the oil drainage passage and moves in the axial direction and is discharged to the oil drainage port. Is done.
Therefore, even when the lubricating oil supplied to the thrust bearing structure increases, the oil around the thrust bearing can be more reliably prevented from leaking to other locations.

  According to a preferred embodiment of the present invention, the oil discharge passage opens in the oil sump space, extends axially from the opening to an axial position avoiding the thrust bearing structure, and further downwards from the axial position. It extends to communicate with an oil outlet located in the lower part of the housing.

  Thus, the oil discharge passage opens in the oil sump space, extends in the axial direction from the opening to the axial position avoiding the thrust bearing, and further extends downward from the axial position. An oil discharge path can be formed by avoiding a portion where the surrounding structure is dense.

  According to a preferred embodiment of the present invention, the thrust bearing structure includes a disk-shaped thrust collar that rotates together with a rotating shaft, and a turbine-side thrust bearing and compressor that are fixed to the housing by preventing the axial movement of the thrust collar. The oil sump space is formed on the turbine side of the compressor-side thrust bearing, and the oil drain passage opening is positioned radially outward from the radial inner edge of the compressor-side thrust bearing. is doing.

  Since the opening of the oil drainage passage is located radially outward from the radial inner edge of the compressor side thrust bearing, the lubricating oil is blown radially outward by centrifugal force and collected in the radially outer portion of the oil sump space. Enters the oil discharge passage through the opening and moves in the axial direction before reaching the radially inner edge of the compressor side thrust bearing. Therefore, oil leakage to the compressor side can be prevented more reliably.

According to a preferred embodiment of the present invention, one or a plurality of the oil discharge passages are formed,
The opening of the oil discharge path is located on one horizontal side or both sides in the horizontal direction of the rotary shaft above the vertical center of the rotary shaft.

In this way, the opening of the oil discharge passage is located above the center in the vertical direction of the rotating shaft and on one side or both sides in the horizontal direction of the rotating shaft. Even when it is positioned above, even if the portion extending downward of the oil discharge passage is formed in a straight line, it does not interfere with the rotating shaft. Therefore, the formation process of the oil discharge path is facilitated.
In addition, since the opening of the oil discharge passage is located above the center in the vertical direction of the rotating shaft, the lubricating oil accumulated in the upper portion of the oil sump space can be discharged to the oil discharge passage.

  According to the above-described present invention, even when the lubricating oil supplied to the thrust bearing structure increases, oil leakage from the periphery of the thrust bearing structure to other parts can be prevented more reliably.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

  FIG. 1 is an overall configuration diagram of a supercharger according to a first embodiment of the present invention. In this figure, the supercharger 10 according to the first embodiment includes a rotating shaft 12, a compressor impeller 14, and a housing. In this example, the housing includes a bearing housing 16, a turbine housing 18, and a compressor housing 20.

  The rotating shaft 12 has a turbine impeller 11 at one end (left end in FIG. 1). In this example, the turbine impeller 11 is formed integrally with the rotary shaft 12, but the present invention is not limited to this, and the turbine impeller 11 may be separately attached.

  The compressor impeller 14 is connected to the other end (right end in FIG. 1) of the rotary shaft 12 so as to rotate integrally with a shaft end nut 15.

  The bearing housing 16 rotatably supports the rotary shaft 12 with a radial bearing 17. The rotating shaft 12 is supported by the thrust bearing structure 30 so as not to move in the axial direction.

The turbine housing 18 rotatably surrounds the turbine impeller 11 and is connected to the bearing housing 16. The turbine housing 18 includes a scroll chamber 18a into which exhaust gas is introduced from the outside, and an annular flow path 18b that guides the exhaust gas from the scroll chamber 18a to the turbine impeller 11.
Furthermore, a plurality of nozzle blades 19 are arranged in the flow path 18b at regular intervals in the circumferential direction. The nozzle blade 19 is a variable nozzle blade, and it is preferable that the area of the flow path formed between the nozzle blades 19 can be changed. However, the present invention is not limited to this and may be a type without fixed nozzle blades or nozzles.

  The compressor housing 20 rotatably surrounds the compressor impeller 14 and is connected to the bearing housing 16. The compressor housing 20 has a scroll chamber 20a into which compressed air is introduced, and an annular flow path 20b that guides the compressed air from the compressor impeller 14 to the scroll chamber 20a.

  With the above-described configuration, the turbine impeller 11 is rotationally driven by the exhaust gas from the engine, and this rotational force is transmitted to the compressor impeller 14 via the rotary shaft 12, and the compressor impeller 14 compresses air and supercharges the engine. it can.

In the example of FIG. 1, the supercharger 10 is an electric supercharger, and further includes a motor rotor 22 and a motor stator 24.
The motor rotor 22 is a rotor of the electric motor, and the motor stator 24 is a stator of the electric motor. The motor rotor 22 and the motor stator 24 constitute a brushless AC motor.
The motor rotor 22 is preferably fixed to the rotating shaft 12.
It is preferable that this AC motor can cope with high-speed rotation of the rotating shaft 12 (for example, at least 100,000 to 200,000 rpm) and can perform rotational driving during acceleration and regenerative operation during deceleration. The drive voltage of the AC motor is preferably the same as or higher than the DC voltage (for example, 12V) of the battery mounted on the vehicle (for example, 24-36V). By increasing the drive voltage, the AC motor can be reduced in size.

FIG. 2 is a partially enlarged view of FIG.
As shown in FIG. 2, the thrust bearing structure 30 of the present invention includes a disk-shaped thrust collar 32 that rotates together with the rotating shaft 12, a turbine-side thrust bearing 34 that prevents axial movement of the thrust collar 32, and a compressor-side thrust. And a bearing 36.
In this example, the compressor-side thrust bearing 36 has an umbrella shape whose center is expanded toward the compressor.

  The compressor side thrust bearing 36 has an oil supply passage 36a. The oil supply flow path 36a has a function of supplying lubricating oil from the bearing housing 16 to the surface (left surface in FIG. 2) that contacts the thrust collar 32.

3 is a view taken along the line III-III in FIG. 1, and FIG. 4 is a partially enlarged view seen from the line IV-IV in FIG.
As shown in FIGS. 3 and 4, the bearing housing 16 is formed with an oil discharge passage 43 for discharging the lubricating oil from the oil sump space 41 of the thrust bearing structure 30.
As shown in FIG. 4, the oil discharge passage 43 opens into the oil sump space 41, extends in the axial direction from the opening 43 a, and further extends downward as shown by a broken line in FIG. It leads to the oil discharge port 45 located in the position.
With this configuration, when the lubricating oil accumulates in the oil sump space 41, the lubricating oil in the oil sump space 41 enters the oil discharge path 43, moves in the axial direction, and is discharged to the oil discharge port 45.

Preferably, the oil discharge passage 43 extends in the axial direction from the opening 43a to the axial position 43b avoiding the thrust bearing, and further extends downward from the axial position 43b to be located at the lower portion of the bearing housing 16. It leads to the exit 45.
With this configuration, the oil discharge passage 43 can be formed while avoiding a portion where the structure around the thrust bearing structure 30 is dense.

In the first embodiment, the oil sump space 41 is formed on the turbine side with respect to the compressor-side thrust bearing 36, and the opening 43 a of the oil discharge passage is located on the radially outer side from the radial inner edge of the compressor-side thrust bearing 36. is doing.
With this configuration, before the lubricating oil that has been blown radially outward by centrifugal force and accumulated in the radially outer portion of the oil reservoir space 41 reaches the radially inner edge of the radial compressor-side thrust bearing 36, the oil discharge path is formed from the opening 43a. 43 and moves in the axial direction.

In the first embodiment, as shown in FIG. 3, two oil discharge passages 43 are formed, and the opening 43 a of the oil discharge passage 43 rotates above the center in the vertical direction of the rotary shaft 12. It is located on both sides of the shaft 12 in the horizontal direction. In addition, the number of the oil discharge path 43 may be one, and in this case, the opening 43a of the oil discharge path 43 is located on one side in the horizontal direction of the rotary shaft 12 above the vertical center of the rotary shaft 12. Good.
With this configuration, even when the rotary shaft 12 is positioned above the vertical center, even if the portion extending downward of the oil discharge passage 43 is formed linearly, this portion interferes with the rotary shaft 12. It will disappear. Therefore, the oil discharge path 43 can be easily formed.
Further, since the opening 43 a of the oil discharge passage 43 is located above the center in the vertical direction of the rotating shaft 12, it is possible to discharge the lubricating oil accumulated in the upper portion of the oil sump space 41 to the oil discharge passage 43. It becomes.

In addition, if the other structure of the supercharger shown in FIGS. 1-4 is also demonstrated, a supercharger will have the fixed partition 26, the oil draining member 28, and the sealing member 29 further.
In this example, the fixed partition wall 26 is a partition wall that is fixed to the bearing housing 16 and partitions the compressor-side thrust bearing 36 and the motor rotor 22.
The oil draining member 28 is located between the fixed partition wall 26 and the compressor side thrust bearing 36, is fixed to the rotating shaft 12, and rotates together with the rotating shaft 12. The oil draining member 28 has a vertical surface 28 a that is larger than the hollow through hole of the compressor-side thrust bearing 36 and is substantially orthogonal to the rotating shaft 12.
The seal member 29 seals between the oil draining member 28 and the fixed partition wall 26 in a liquid-tight manner.

  In the supercharging according to the first embodiment having the above-described configuration, the oil discharge passage 43 for discharging the lubricating oil from the oil reservoir space 41 of the thrust bearing structure 30 opens into the oil reservoir space 41, and the thrust bearing is supplied from the opening 43a. Since it extends in the axial direction to the avoided axial position 43b, and further extends downward from the axial position 43b, it leads to the oil discharge port 45 located at the lower part of the bearing housing 16, so that the oil sump space When the lubricating oil accumulates in 41, the lubricating oil in the oil sump space 41 enters the oil discharge passage 43, moves in the axial direction, and is discharged to the oil discharge port 45. Therefore, even when the lubricating oil supplied to the thrust bearing structure 30 increases, it is possible to more reliably prevent the lubricating oil around the thrust bearing structure 30 from leaking over the seal member 29 to the motor side.

[Second Embodiment]
FIG. 5 corresponds to FIG. 4 and shows a second embodiment of the present invention.
Also in FIG. 5, the thrust bearing structure 30 includes a disk-shaped thrust collar 32 that rotates together with the rotating shaft 12, a turbine-side thrust bearing 34 that prevents axial movement of the thrust collar 32, and a compressor-side thrust bearing 36. .
The compressor-side thrust bearing 36 has a flat plate shape in FIG.
Also in the second embodiment, the oil discharge passage 43 opens into the oil sump space 41, extends in the axial direction from the opening 43a, and further extends downward as shown by a broken line in FIG. It leads to the oil discharge port 45 located in the position.
Other configurations may be the same as those in the first embodiment.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, in the first and second embodiments described above, the motor rotor 22 is a supercharger having an electric motor provided between the compressor side thrust bearing 36 and the compressor impeller 14, but the present invention is not limited to this. . That is, the present invention can be applied to a supercharger that does not have an electric motor. For example, in FIG. 1, the motor rotor 22, the motor stator 24, and the like, which are components of the electric motor, can be omitted. In this case, the oil discharge passage 43 more reliably prevents oil from leaking beyond the seal member 29 to the compressor side.
In the above-described embodiment, the oil discharge passage 43 is formed in the bearing housing 16. However, the oil discharge passage 43 is formed in a housing in which the bearing housing 16 and one or both of the turbine housing 18 and the compressor housing 20 are integrally formed. It may be formed.
In the above-described embodiment, the case where two or one oil discharge passages are formed has been described, but three or more oil discharge passages may be formed.

It is sectional drawing which shows the whole structure of the supercharger by 1st Embodiment of this invention. It is the elements on larger scale of FIG. It is the III-III arrow directional view of FIG. It is the elements on larger scale seen from the IV-IV line of FIG. It is a fragmentary sectional view of the supercharger by 2nd Embodiment of this invention, and respond | corresponds to FIG. It is a figure which shows the thrust bearing structure of patent document 1. FIG. It is a schematic diagram of the bearing apparatus of patent document 2. FIG. 6 is a schematic diagram of a supercharger disclosed in Patent Document 3.

Explanation of symbols

10 electric turbocharger, 11 turbine impeller, 12 rotating shaft,
14 compressor impeller, 15 shaft end nut,
16 bearing housing, 17 radial bearing,
18 turbine housing, 18a scroll chamber, 18b flow path,
19 Nozzle blades, 20 Compressor housing, 20a Scroll chamber,
20b flow path, 22 motor rotor, 24 motor stator,
26 fixed partition, 28 oil draining member, 29 sealing member,
30 thrust bearing structure, 32 thrust collar,
34 Turbine side thrust bearing, 36 Compressor side thrust bearing,
36a Oil supply flow path, 41 Oil reservoir space, 43 Oil discharge path 43a Opening, 45 Oil discharge port

Claims (4)

A turbine impeller that is rotationally driven by exhaust gas, a compressor impeller that is rotationally driven by the rotation of the turbine impeller and compresses air, a rotational shaft that connects the turbine impeller and the compressor impeller, and a housing that houses the rotational shaft inside And a thrust bearing structure that rotatably supports a thrust force acting on the rotating shaft,
The housing is formed with an oil discharge passage for discharging the lubricating oil from the oil reservoir space of the thrust bearing structure,
The oil discharge passage is open to the oil sump space, extends in the axial direction from the opening, further extends downward, and communicates with an oil discharge port located at a lower portion of the housing. Turbocharger.   The oil discharge passage opens in the oil reservoir space, extends in the axial direction from the opening to an axial position avoiding the thrust bearing structure, and further extends downward from the axial position to be positioned at a lower portion of the housing. The supercharger according to claim 1, wherein the turbocharger is adapted to communicate with an oil discharge port. The thrust bearing structure comprises a disc-shaped thrust collar that rotates together with a rotating shaft, and a turbine-side thrust bearing and a compressor-side thrust bearing that are fixed to the housing by preventing the axial movement of the thrust collar.
The oil sump space is formed on the turbine side of the compressor side thrust bearing,
2. The supercharger according to claim 1, wherein an opening of the oil drainage passage is located radially outside an inner edge in a radial direction of the compressor side thrust bearing. One or a plurality of the oil discharge passages are formed,
2. The excessive passage according to claim 1, wherein the opening of the oil discharge path is located on one side in the horizontal direction or both sides in the horizontal direction of the rotary shaft above the vertical center of the rotary shaft. Feeder.

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