JP5277901B2 - Lubricating oil seal structure for vehicle turbocharger - Google Patents

Description

  The present invention relates to a lubricating oil seal structure for a supercharger for a vehicle that reduces the amount of lubricating oil leaking to the compressor side.

  Supplying air whose density has been increased by the compressor to the engine is called supercharging, and among these, the exhaust gas turbocharger is used to cover the driving work of the compressor by exhaust energy. Call it.

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 connecting 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 by the connecting shaft. The impeller compresses air and supercharges the engine.
Hereinafter, the exhaust turbine supercharger is simply referred to as “supercharger”.

  In a supercharger for a vehicle mounted on an automobile or the like, if lubricating oil that lubricates the bearing unit is mixed into the supercharged air, the engine performance may deteriorate and the exhaust gas may be contaminated. Therefore, various seal structures have been conventionally proposed as means for improving the oil seal performance of a vehicle supercharger and preventing oil leakage (for example, Patent Documents 1 to 4).

As shown in FIG. 6, Patent Document 1 provides a vent hole 50 that leads to the outside in the middle of a turbine-side oil labyrinth 7 that performs a lubricating oil seal on the turbine side of an exhaust gas turbine supercharger. The turbine-side sealing air is discharged outside through the turbine-side sealing air so that the turbine-side sealing air does not enter much into the bearing stand 55 and the like serving as a seal space, and the lubricating oil mist from the inside of the bearing stand 55 etc. to the compressor side It is intended to prevent leakage of water.
In this figure, 53 is a turbine disk, 54 is a rotor shaft, 57 is a turbine side oil labyrinth, and 58 is a turbine rear surface.

  In Patent Document 2, as shown in FIG. 7, an oil supply passage 62 for supplying lubricating oil to the rolling bearings 64 and 65 and the oil film buffer layer 68 and the lubricating oil flowing out from the rolling bearings 64 and 65 and the oil film buffer layer 68 are recovered. In a turbocharger bearing device including an oil recovery chamber 63 for sealing and a seal ring 69 interposed between the bearing housing 61 and the turbine shaft 63, the bearing housing 61 is positioned between the rolling bearing 65 and the seal ring 69. Thus, an oil recovery groove 66 that is recessed in a concave shape is formed.

  In Patent Document 3, as shown in FIG. 8, the turbine is rotated by the gas flow of the exhaust gas, and the compressor 73 provided on the same rotation shaft as the turbine is rotated to compress and feed the intake air. In the supercharger, a labyrinth fin 76 is provided on the bearing support 72 facing the rotation shaft so as to prevent the lubricating oil supplied to the bearing of the rotation shaft 71 from leaking to the outside of the supercharger, and located inside the labyrinth fin. A fin 78 is integrally formed on the outer periphery of the sleeve 77 on the rotating shaft so that the lubricating oil transmitted on the surface of the rotating shaft can be swung away by the centrifugal force generated by the rotation of the rotating shaft.

  As shown in FIG. 9, Patent Document 4 includes a thrust bearing 80 that rotatably supports a thrust force acting on the turbine shaft 81. The thrust bearing 80 includes a disk-shaped thrust collar 82 that rotates together with the turbine shaft, and a turbine-side thrust bearing 84 and a compressor-side thrust bearing 86 that prevent axial movement of the thrust collar. The compressor-side thrust bearing 86 includes an oil supply passage 86a for supplying lubricating oil from the housing to the surface in contact with the thrust collar, an annular concave groove 86b provided on the inner surface of the hollow through hole through which the turbine shaft passes, And an oil discharge passage 86c for dropping the lubricating oil accumulated in the concave groove downward.

JP-A-9-189232, “Lubricating oil seal device for exhaust gas turbine supercharger” Japanese Patent Application Laid-Open No. 2000-110577, “Supercharger Bearing Device” Japanese Patent Application Laid-Open No. 2003-293783, “oil seal device for supercharger” JP 2008-31949 A, “Supercharger”

  The conventional lubricating oil seal structure described above can be summarized as follows: Patent Document 1 uses a labyrinth seal, Patent Document 2 includes an oil recovery groove, and Patent Document 3 includes a labyrinth seal and a fin that utilizes centrifugal force. The used one, Patent Document 4, is a thrust bearing on the compressor side provided with an inner circumferential groove and an oil discharge passage.

However, these lubricating oil seal structures have the following problems.
(1) The structure of Patent Document 1 requires a space for installing a labyrinth seal. Moreover, since the shape is complicated, it is difficult to process and the manufacturing cost is high.
(2) The structure of Patent Document 2 requires a space for providing an oil recovery groove.
(3) The structure of Patent Document 3 requires a space for installing a labyrinth seal. Moreover, since the shape is complicated, it is difficult to process and the manufacturing cost is high.
(4) Since the structure of Patent Document 4 is limited in the thickness of the thrust bearing, the discharge channel area is limited. Further, the shape of the discharge channel is unclear.

  The present invention has been developed to solve the above-described conventional problems. That is, an object of the present invention is to provide a vehicular supercharger capable of increasing the discharge flow passage area from the thrust bearing and reducing the amount of lubricating oil leaking to the compressor side without increasing the installation space. It is to provide a lubricating oil seal structure.

According to the present invention, a lubricating oil seal for a supercharger for a vehicle comprising a turbine shaft having a turbine impeller at one end, a compressor impeller that is rotationally driven by the turbine shaft, and a bearing housing that rotatably supports the turbine shaft. Structure,
A flat compressor-side thrust bearing having a housing-side surface having a thrust support surface that rotatably supports a thrust force acting on the turbine shaft acting on the turbine shaft, and a compressor-side back surface communicating with a lubricating oil discharge port in the bearing housing. With
The compressor side thrust bearing has a hollow through hole through which the turbine shaft passes, an oil discharge groove, and an oil supply groove.
The oil discharge groove includes an arc-shaped groove that surrounds the thrust support surface in an arc shape and a lower groove communicating with the groove, and the lower groove communicates with a lubricating oil discharge port in the bearing housing.
Further, the lubricating oil is discharged from a plurality of oil supply passages for supplying the lubricating oil to a plurality of locations on the thrust support surface from the oil supply concave groove and an annular concave groove provided on the inner surface of the hollow through hole to the oil discharge concave groove There is provided a lubricating oil seal structure for a supercharger for a vehicle having a plurality of oil discharge passages.

According to a preferred embodiment of the present invention, a disc-shaped thrust collar that rotates together with the turbine shaft is provided.
The housing side surface is fixed in a liquid-tight and detachable manner with a seal surface orthogonal to the turbine axis of the bearing housing,
The thrust support surface is a ring-shaped plane that surrounds the hollow through-hole, contacts the thrust collar, and has a radial oil groove;
The arc-shaped concave groove communicates with the radial oil groove of the thrust support surface,
The oil supply concave groove surrounds the oil discharge concave groove in an arc shape with the seal surface therebetween, and communicates with a lubricating oil supply hole in the bearing housing.

  Further, the plurality of oil supply passages are a plurality of oil outflow holes perpendicular to the thrust support surface and spaced in the circumferential direction, and radial diagonal penetrations directly connecting the oil outflow holes and the oil supply grooves. It consists of a hole.

  The plurality of oil discharge passages extend radially, vertically, or obliquely in the rotational direction of the turbine shaft from the turbine shaft.

A fixed partition that partitions the compressor-side thrust bearing and the compressor impeller; an oil draining member that is positioned between the fixed partition and the compressor-side thrust bearing; and that rotates together with the turbine shaft; and And a sealing member that seals the space in a liquid-tight manner,
The oil draining member has a vertical surface that is larger than the hollow through hole of the compressor-side thrust bearing and substantially perpendicular to the turbine shaft.

  According to the above configuration of the present invention, the compressor-side thrust bearing that rotatably supports the thrust force acting on the compressor acting on the turbine shaft is a flat member having a housing-side surface and a compressor-side back surface. By simply fixing the surface of the bearing housing in a liquid-tight and detachable manner, the compressor-side thrust bearing can be installed without increasing the installation space.

  Further, the compressor side thrust bearing has an oil supply groove, and the lubricating oil supplied from the lubricating oil supply hole in the bearing housing to the oil supply groove is formed on the thrust support surface via a plurality of oil supply channels. Since it is supplied to a plurality of locations, a sufficient amount of lubricating oil can be supplied to the thrust support surface.

  Furthermore, since the lubricating oil discharged from the thrust support surface flows through the arc-shaped groove that surrounds the thrust support surface in an arc shape, it flows into the lower groove that communicates with this, greatly increasing the discharge flow path area from the thrust bearing. The lubricating oil discharged from the thrust support surface can be smoothly discharged to the lubricating oil discharge port in the bearing housing.

  In addition, since there are a plurality of oil discharge passages for discharging the lubricating oil from the annular groove provided on the inner surface of the hollow through hole through which the turbine shaft passes, to the oil discharge groove, the gap between the turbine shaft and the hollow through hole is provided. The leaked lubricating oil can be flowed into the lower groove through the plurality of oil discharge passages. As a result, the amount of lubricating oil that leaks into the gap between the turbine shaft and the hollow through-hole and further leaks to the compressor-side back surface beyond the annular concave groove on the inner surface of the hollow through-hole can be greatly reduced.

  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 vehicular supercharger provided with a lubricating oil seal structure of the present invention. In this figure, a vehicle supercharger 10 of the present invention includes a turbine shaft 12, a compressor impeller 14, and a bearing housing 16. In this figure, the turbine housing and the compressor housing are not shown.

  The turbine shaft 12 has a turbine impeller 11 at one end (the left end in the figure). In this example, the turbine impeller 11 is integrally formed with the turbine shaft 12. However, 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 the drawing) of the turbine shaft 12 so as to rotate integrally with a shaft end nut 15.

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

  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 turbine shaft 12 so that air is compressed by the compressor impeller 14 and supercharged to the engine. It has become.

  In this figure, the thrust bearing 30 includes a disk-shaped thrust collar 32 that rotates together with the turbine shaft 12, and a turbine-side thrust bearing 34 and a compressor-side thrust bearing 36 that prevent the thrust collar 32 from moving in the axial direction.

In FIG. 1, the vehicle supercharger further includes a fixed partition wall 26, an oil draining member 28, and a seal member 29.
In this example, the fixed partition wall 26 is a partition wall that is fixed to the bearing housing 16 and partitions between the compressor side thrust bearing 36 and the compressor impeller.
The oil draining member 28 is located between the fixed partition wall 26 and the compressor side thrust bearing 36, is fixed to the turbine shaft 12, and rotates together with the turbine shaft 12. The oil draining member 28 has a vertical surface that is larger than the hollow through hole of the compressor-side thrust bearing 36 and is substantially orthogonal to the turbine shaft 12.
The seal member 29 seals between the oil draining member 28 and the fixed partition wall 26 in a liquid-tight manner.

With this configuration, the lubricating oil that has flowed to the compressor side beyond the compressor-side thrust bearing 36 and has reached the vertical surface of the oil draining member 28 can be swung radially outward by centrifugal force due to the high-speed rotation of the oil draining member 28. it can.
Accordingly, the amount of lubricating oil reaching the seal member 29 located on the opposite side of the vertical surface in the axial direction can be greatly reduced, the amount of lubricating oil reaching the seal portion on the compressor side is reduced, and the performance of the seal is ensured. The reliability of the entire turbocharger can be improved.

  FIG. 2 is a view taken along the line AA of FIG. 1 showing the first embodiment of the present invention. 3 is a cross-sectional view taken along line B-O-C in FIG.

As shown in FIGS. 2 and 3, the compressor-side thrust bearing 36 is a flat plate-like component (in this example, a disk member) having a housing-side surface 36a and a compressor-side back surface 36b.
The housing side surface 36a rotatably supports a thrust force acting on the turbine shaft 12 toward the compressor side. Further, the compressor side rear surface 36 b communicates with the lubricating oil discharge port 16 b through the oil discharge cavity 16 a in the bearing housing 16.

In FIG. 2, the compressor side thrust bearing 36 has a hollow through hole 36c through which the turbine shaft 12 passes, a thrust support surface 37 provided on the housing side surface 36a, an oil discharge groove 38, and an oil supply groove 39. .
In this figure, reference numeral 36d denotes mounting through holes, and in this example, four are distributed in the circumferential direction. The compressor-side thrust bearing 36 is fixed to the bearing housing 16 in a liquid-tight and detachable manner on a seal surface 16c orthogonal to the turbine shaft by bolts (not shown) passing through the mounting through holes 36d.
The seal surface 16c is provided in a portion of the housing side surface 36a of the compressor side thrust bearing 36 above a lower concave groove 38b described later.

The thrust support surface 37 of the housing side surface 36a is a surface that does not contact the seal surface 16c of the bearing housing 16, but instead contacts the thrust collar 32 and prevents its axial movement.
The thrust support surface 37 is a ring-shaped flat surface 37a that is substantially flush with the housing-side surface 37a, surrounds the hollow through hole 36c, and has radial oil grooves 37b. In this example, it consists of four ring-shaped planes 37a divided in the circumferential direction by four radial oil grooves 37b.

The oil discharge groove 38 includes an arcuate groove 38a surrounding the thrust support surface 37 in an arcuate shape and a lower groove 38b communicating with the arcuate groove 38a.
The arcuate groove 38 a communicates with the radial oil groove 37 b of the thrust support surface 37.
Further, the lower concave groove 38b does not contact the seal surface 16c of the bearing housing 16, and communicates with the lubricating oil discharge port 16b through the oil discharge cavity 16a in the bearing housing 16 as shown in FIG. Yes.

  The oil supply groove 39 surrounds the arcuate groove 38a of the oil discharge groove 38 in an arc shape with the seal surface 16c (that is, the housing side surface 36a) therebetween, and communicates with the lubricating oil supply hole 16d in the bearing housing 16. doing.

  In FIG. 2, the compressor-side thrust bearing 36 is further provided on the inner surfaces of the plurality of oil supply passages 40 for supplying the lubricating oil from the oil supply concave grooves 39 to a plurality of locations on the thrust support surface 37 and the hollow through hole 36c. And a plurality of oil discharge passages 42 for discharging the lubricating oil from the annular groove 41 to the oil discharge groove 38 (lower groove 38b).

  A plurality (four in this example) of oil supply passages 40 are orthogonal to the thrust support surface 37 and spaced apart in the circumferential direction (four in this example), oil outflow holes 40a, It consists of a plurality of radial (four in this example) diagonal through-holes 40b directly connecting to the oil supply groove 39.

  A plurality (three in this example) of oil discharge passages 42 extend radially from the axis of the turbine shaft 12.

FIG. 4 is an explanatory diagram showing the flow of lubricating oil in the compressor-side thrust bearing of the present invention. In FIG. 4A, the housing side surface 36a, the thrust support surface 37, and the turbine shaft 12 are indicated by oblique lines with different pitches. Further, the oil discharge groove 38 (the arc-shaped groove 38a and the lower groove 38b) and the oil supply groove 39 are shown without hatching. These recessed grooves 38 and 39 are grooves recessed inward from the housing side surface 36a. Further, the oil supply flow path 40 and the oil discharge flow path 42 are indicated by thin thin lines.
4A, the seal surface 16c is a portion above the upper end of the lower concave groove 38b. In this range, the housing side surface 36a is fixed to the seal surface 16c of the bearing housing 16 in a liquid-tight manner. Therefore, the oil discharge groove 38 and the oil supply groove 39 are liquid-tightly partitioned by the housing side surface 36a (seal surface 16c) located between them.

  According to the configuration of the present invention described above, the compressor-side thrust bearing 36 that rotatably supports the thrust force acting on the compressor side acting on the turbine shaft 12 is a flat plate member having a housing-side surface 36a and a compressor-side back surface 36b. Therefore, the compressor-side thrust bearing 36 can be installed by simply fixing the housing-side surface 36a to the bearing housing 16 in a liquid-tight and detachable manner without increasing the installation space.

  The compressor side thrust bearing 36 has a hollow through hole 36c through which the turbine shaft 12 passes, a thrust support surface 37 provided on the housing side surface, an oil discharge groove 38, and an oil supply groove 39. The lubricating oil a supplied from the lubricating oil supply hole 16d in the housing 16 to the oil supply concave groove 39 is supplied to a plurality of locations on the thrust support surface 37 via the plurality of oil supply passages 40. 17 can be supplied with a sufficient amount of lubricating oil b.

  Further, the lubricating oil c discharged from the thrust support surface 37 flows into the lower concave groove 38b that communicates with this through the arc-shaped concave groove 38a surrounding the thrust support surface 37 in an arc shape. The area of the discharge channel can be greatly increased, and the lubricating oil c discharged from the thrust support surface 37 can be smoothly discharged to the lubricating oil discharge port 16b through the oil discharge cavity 16a in the bearing housing 16.

  Further, a plurality of oil discharge passages 42 for discharging the lubricating oil d from the annular groove 41 provided on the inner surface of the hollow through hole 36c through which the turbine shaft 12 passes to the oil discharge groove 38 (lower groove 38b) are provided. Therefore, the lubricating oil d leaked into the gap between the turbine shaft 12 and the hollow through hole 36c can be flowed into the lower groove through the plurality of oil discharge passages 42. As a result, the leakage amount of the lubricating oil e that leaks into the gap between the turbine shaft 12 and the hollow through hole 36c and further leaks to the compressor-side back surface 16b beyond the annular concave groove 41 on the inner surface of the hollow through hole is greatly reduced. be able to.

FIG. 5 is an AA arrow view of FIG. 1 showing a second embodiment of the present invention.
In this example, a plurality (three in this example) of oil discharge passages 42 extend vertically downward from the axis of the turbine shaft 12. Further, a plurality of oil discharge passages 42 may be provided obliquely in the rotational direction of the turbine shaft 12.
Also with these configurations, the lubricating oil d leaking into the gap between the turbine shaft 12 and the hollow through hole 36c can be caused to flow through the plurality of oil discharge passages 42 into the lower concave groove. As a result, the leakage amount of the lubricating oil e that leaks into the gap between the turbine shaft 12 and the hollow through hole 36c and further leaks to the compressor-side back surface 16b beyond the annular concave groove 41 on the inner surface of the hollow through hole is greatly reduced. be able to.

The amount of leakage of the lubricating oil e leaking to the compressor side rear surface 16b was compared using the compressor side thrust bearing 36 of the present invention shown in FIG. 2 and a conventional compressor side thrust bearing. The test results obtained are shown in Table 1.
The conventional compressor-side thrust bearing is the same as the compressor-side thrust bearing 36 of the present invention except that the annular groove 41 and the plurality of oil discharge passages 42 are not provided.
In this test, the actual operating conditions were simulated, and the turbine rotation speed was kept at 0.39 to 88,000 rpm and the lubricating oil flow rate was kept at 0.72 to 2.00 L / min for 10 minutes.

  From Table 1, it was confirmed that the leakage amount of the lubricating oil e leaking to the compressor-side back surface 16b can be significantly reduced by 95% or more according to the present invention as compared with the prior art.

  In addition, this invention is not limited to embodiment mentioned above, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

1 is an overall configuration diagram of a vehicular supercharger equipped with a lubricating oil seal structure of the present invention. It is an AA arrow line view of Drawing 1 showing a 1st embodiment of the present invention. It is sectional drawing in the BOC line of FIG. It is explanatory drawing which shows the flow of the lubricating oil in the compressor side thrust bearing of this invention. It is an AA arrow line view of Drawing 1 showing a 2nd embodiment of the present invention. It is a schematic diagram which shows the seal structure of patent document 1. FIG. It is a schematic diagram which shows the seal structure of patent document 2. FIG. It is a schematic diagram which shows the seal structure of patent document 3. It is a schematic diagram which shows the seal structure of patent document 4.

Explanation of symbols

10 vehicle turbocharger, 11 turbine impeller, 12 turbine shaft,
14 compressor impeller, 15 shaft end nut,
16 Bearing housing, 16a Cavity for oil discharge,
16b Lubricating oil outlet, 16c Seal surface, 16d Lubricating oil supply hole,
17 radial bearings,
26 fixed partition, 28 oil draining member, 29 sealing member,
30 thrust bearing, 32 thrust collar,
34 Turbine side thrust bearing,
36 Compressor side thrust bearing,
36a housing side surface, 36b compressor side back surface,
36c hollow through hole, 36d through hole for mounting,
37 Thrust support surface, 37a Ring-shaped plane, 37b Radial oil groove,
38 oil discharge groove, 38a arc-shaped groove, 38b lower groove,
39 Oil supply groove, 40 Oil supply flow path, 40a Oil outflow hole,
40b oblique through hole, 41 annular groove, 42 oil discharge channel

Claims (5)

A lubricating oil seal structure for a supercharger for a vehicle comprising a turbine shaft having a turbine impeller at one end, a compressor impeller that is driven to rotate by the turbine shaft, and a bearing housing that rotatably supports the turbine shaft,
A flat compressor-side thrust bearing having a housing-side surface having a thrust support surface that rotatably supports a thrust force acting on the turbine shaft acting on the turbine shaft, and a compressor-side back surface communicating with a lubricating oil discharge port in the bearing housing. With
The compressor side thrust bearing has a hollow through hole through which the turbine shaft passes, an oil discharge groove, and an oil supply groove.
The oil discharge groove is formed in the compressor side thrust bearing,
The oil discharge groove includes an arcuate groove surrounding the thrust support surface in an arcuate shape and a lower groove communicating with the arcuate groove, and the arcuate groove is entirely formed in the turbine shaft rotation direction. Open to the side, and the lower groove communicates with a lubricating oil discharge port in the bearing housing,
Additionally, lubricating oil and from said oil supply groove thrust support surface a plurality of oil supply passages for supplying lubricating oil to a plurality of locations of the concave groove of the annular provided on the inner surface of the hollow through hole in the oil discharge groove have a plurality of oil discharge passage for discharging,
A lubricating oil seal structure for a supercharger for a vehicle , wherein the lubricating oil discharged from the thrust support surface flows into the lower concave groove through the arc-shaped concave groove . A disc-shaped thrust collar that rotates with the turbine shaft;
The housing side surface is fixed in a liquid-tight and detachable manner with a seal surface orthogonal to the turbine axis of the bearing housing,
The thrust support surface is a ring-shaped plane that surrounds the hollow through-hole, contacts the thrust collar, and has a radial oil groove;
The arc-shaped concave groove communicates with the radial oil groove of the thrust support surface,
2. The vehicle according to claim 1, wherein the oil supply concave groove surrounds the oil discharge concave groove in an arc shape with the seal surface therebetween and communicates with a lubricating oil supply hole in a bearing housing. Lubricant seal structure for turbochargers.   The plurality of oil supply passages include a plurality of oil outflow holes orthogonal to the thrust support surface and spaced in the circumferential direction, and radial oblique through holes that directly connect the oil outflow holes and the oil supply concave grooves. The lubricating oil seal structure for a supercharger for a vehicle according to claim 1, comprising:   2. The lubricating oil seal structure for a supercharger for a vehicle according to claim 1, wherein the plurality of oil discharge passages extend radially, vertically, or obliquely in a rotational direction of the turbine shaft from the turbine shaft. A fixed partition that partitions between the compressor side thrust bearing and the compressor impeller, an oil draining member that is positioned between the fixed partition and the compressor side thrust bearing, and that rotates with the turbine shaft; and between the oil drain member and the fixed partition. A seal member that seals liquid-tightly,
2. The lubricating oil seal structure for a supercharger for a vehicle according to claim 1, wherein the oil draining member has a vertical surface that is larger than a hollow through-hole of a compressor-side thrust bearing and substantially perpendicular to the turbine shaft. .

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