JP6107004B2 - Turbocharger - Google Patents

Description

  The present invention relates to a supercharger in which lubricating oil is supplied to a bearing hole.

  2. Description of the Related Art Conventionally, a turbocharger is known in which a turbine shaft having a turbine impeller provided at one end and a compressor impeller provided at the other end is rotatably held by a bearing housing. Such a supercharger is connected to the engine, the turbine impeller is rotated by exhaust gas discharged from the engine, and the compressor impeller is rotated through the turbine shaft by the rotation of the turbine impeller. Thus, the supercharger compresses air and sends it to the engine as the compressor impeller rotates.

  A bearing hole is formed in the bearing housing, and a bush functioning as a bearing is disposed in the bearing hole. The bush has an insertion hole through which the turbine shaft is inserted, and a sliding surface that receives a radial load is formed on an inner peripheral surface thereof. The turbocharger described in Patent Document 1 is a kind of such a bush, and is provided with a semi-floating metal in which the movement of the turbine shaft in the rotational direction is restricted. In addition, on the slip surface formed on the inner peripheral surface of the semi-floating metal, a guide groove that communicates both axial ends of the turbine shaft is provided to improve the lubrication performance on the slip surface by promoting the flow of the lubricating oil. It has been.

  Moreover, as a bush distribute | arranged to a bearing hole, there exists a full floating metal which rotates at the rotation speed lower than a turbine shaft with rotation of a turbine shaft. Since the full floating metal rotates relative to both the turbine shaft and the bearing hole, a slip surface is formed on both the inner peripheral surface side and the outer peripheral surface side. A configuration in which the guide groove is provided in the full floating metal or the bearing hole in which the full floating metal is disposed is also conceivable.

JP 2007-23858 A

  For example, when foreign matter is mixed in the lubricating oil and enters the guide groove, the foreign matter is affected by the flow of lubricating oil in the rotational direction of the turbine shaft and jumps out of the guide groove between the turbine shaft and the sliding surface. There is a risk of biting.

  An object of the present invention is to provide a supercharger capable of suppressing biting of foreign matter into a sliding surface even if foreign matter enters a guide groove for promoting the flow of lubricating oil on the sliding surface. .

In order to solve the above problems, a supercharger according to the present invention includes a supercharger main body, a bearing hole formed in the supercharger main body, and rotatably accommodated in the bearing hole, and a turbine impeller at one end. A turbine shaft provided with a compressor impeller at the other end thereof, two sliding surfaces spaced apart in the axial direction of the turbine shaft and supporting the turbine shaft, and the sliding from the radially outer side of the sliding surface An oil hole that penetrates to the surface and guides the lubricating oil to the sliding surface, and a guide groove that is formed in the two sliding surfaces and extends in the axial direction of the turbine shaft to distribute the lubricating oil, wherein is accommodated in the bearing bore, a semi-floating metal movement in the axial direction and the rotational direction of the turbine shaft is restricted with respect to the bearing hole, wherein the guide groove, the semi-floating forming the guide groove Metal wall Among these, are formed by a wall of the rotation direction front side of the turbine shaft, the foreign matter mixed in the lubricating oil which has flowed into the guide grooves, have a foreign object holder for holding to the guide groove, from the oil hole , it extends to the end face in the axial direction of the turbine shaft of the semi-floating metal, and wherein in the direction in which the two sliding surfaces come close than oil hole, the Rukoto formed leaving the sliding surface To do.

  Of the angle formed by the tangent of a portion of the sliding surface that is continuous with the wall portion on the front side in the rotation direction of the turbine shaft and the wall portion on the front side in the rotation direction of the turbine shaft that forms the foreign matter holding portion, the wall 90 degrees or less may be sufficient as the angle of the rotation direction front side of this turbine shaft from a part.

  The wall portion on the front side in the rotational direction of the turbine shaft that forms the foreign substance holding portion may be a curved surface that is curved in an arc.

  The guide groove may have a symmetrical shape on the front side in the rotational direction of the turbine shaft and a shape on the rear side in the rotational direction with respect to the surface of the guide groove that is the center in the rotational direction of the turbine shaft. Good.

The semi-floating metal is provided on an axial end face of the front Symbol turbine shaft may be provided with a thrust bearing surface for receiving a thrust load.

  According to the present invention, even if foreign matter enters a guide groove for promoting circulation of the lubricating oil on the sliding surface, it is possible to suppress the foreign matter from entering the sliding surface.

It is a schematic sectional drawing of the supercharger in 1st Embodiment. It is the elements on larger scale inside the bearing housing of FIG. It is explanatory drawing for demonstrating a semi-floating metal. It is explanatory drawing for demonstrating the flow of the foreign material in a guide groove. It is explanatory drawing for demonstrating the guide groove in a modification. It is explanatory drawing for demonstrating the bearing structure in 2nd Embodiment. It is explanatory drawing for demonstrating a full floating metal. It is sectional drawing of a full floating metal and a turbine shaft.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a supercharger C in the first embodiment. Hereinafter, the direction of arrow F shown in FIG. 1 will be described as the front side of the supercharger C, and the direction of arrow R will be described as the rear side of the supercharger C. As shown in FIG. 1, the supercharger C includes a supercharger main body 1. The supercharger body 1 includes a bearing housing 2, a turbine housing 4 connected to the front side of the bearing housing 2 by a fastening bolt 3, a compressor housing 6 connected to the rear side of the bearing housing 2 by a fastening bolt 5, Are formed integrally.

  The bearing housing 2 is formed with a bearing hole 2a penetrating in the front-rear direction of the supercharger C (the axial direction of the turbine shaft 7). By the semi-floating metal 20 (bush) accommodated in the bearing hole 2a, A turbine shaft 7 is rotatably supported. A turbine impeller 8 is integrally fixed to a front end portion (one end) of the turbine shaft 7, and the turbine impeller 8 is rotatably accommodated in the turbine housing 4. A compressor impeller 9 is integrally fixed to the rear end (other end) of the turbine shaft 7, and the compressor impeller 9 is rotatably accommodated in the compressor housing 6.

  The compressor housing 6 is formed with an air inlet 10 that opens to the rear side of the supercharger C and is connected to an air cleaner (not shown). Further, in a state where the bearing housing 2 and the compressor housing 6 are connected by the fastening bolt 5, a diffuser flow path 11 that compresses and pressurizes air is formed by the facing surfaces of both the housings 2 and 6. The diffuser passage 11 is formed in an annular shape from the radially inner side to the outer side of the turbine shaft 7 (compressor impeller 9), and communicates with the intake port 10 via the compressor impeller 9 on the radially inner side. ing.

  Further, the compressor housing 6 is provided with an annular compressor scroll passage 12 positioned on the radially outer side of the turbine shaft 7 (compressor impeller 9) with respect to the diffuser passage 11. The compressor scroll passage 12 communicates with an intake port of an engine (not shown) and also communicates with the diffuser passage 11. Therefore, when the compressor impeller 9 rotates, fluid is sucked into the compressor housing 6 from the intake port 10, and the sucked fluid is boosted in the diffuser flow path 11 and the compressor scroll flow path 12 to be sucked into the engine intake port. Will be led to.

  The turbine housing 4 is formed with a discharge port 13 that opens to the front side of the supercharger C and is connected to an exhaust gas purification device (not shown). Further, the turbine housing 4 is provided with a flow path 14 and an annular turbine scroll flow path 15 positioned on the radially outer side of the turbine shaft 7 (turbine impeller 8) with respect to the flow path 14. The turbine scroll passage 15 communicates with a gas inlet through which exhaust gas discharged from an exhaust manifold of an engine (not shown) is guided, and also communicates with the passage 14 described above. Therefore, the exhaust gas guided from the gas inlet to the turbine scroll flow path 15 is guided to the discharge port 13 through the flow path 14 and the turbine impeller 8 and rotates the turbine impeller 8 in the flow process. . Then, the rotational force of the turbine impeller 8 is transmitted to the compressor impeller 9 via the turbine shaft 7, and the fluid is boosted by the rotational force of the compressor impeller 9 as described above, and the intake port of the engine Will be led to.

  FIG. 2 is a partially enlarged view of the inside of the bearing housing 2 of FIG. 1, and shows a portion surrounded by a broken-line square in FIG. Hereinafter, the support structure of the turbine shaft 7 by the semi-floating metal 20 accommodated in the bearing hole 2a will be described with reference to FIG.

  The lubricating oil supply unit 21 includes a hole communicating from the outside of the bearing housing 2 to the bearing hole 2a, and supplies the lubricating oil to the bearing hole 2a from the outside of the bearing housing 2. Specifically, the holes constituting the lubricating oil supply unit 21 are branched, and the outlet end 21a and the compressor impeller 9 side (in FIG. 2) are located on the turbine impeller 8 side (left side in FIG. 2) of the bearing hole 2a. The outlet end 21b is located on the right side.

  The semi-floating metal 20 has an insertion hole 20a penetrating in the axial direction of the turbine shaft 7, and is an annular member through which the turbine shaft 7 is inserted. The semi-floating metal 20 is formed with oil holes 20b and 20c penetrating from the inner peripheral surface of the semi-floating metal 20 to the outer peripheral surface.

  Specifically, four oil holes 20b are provided at equal intervals in the circumferential direction at a position facing the outlet end 21a of the lubricating oil supply portion 21 of the semi-floating metal 20, and the oil holes 20c are semi-floating. Four of the metals 20 are provided at equal intervals over the circumferential direction at a position facing the outlet end 21 b of the lubricating oil supply unit 21.

  The semi-floating metal 20 has an inlet end (semi-floating in the oil hole 20b) on the outer peripheral surface of the position where the four oil holes 20b are provided over the circumferential direction of the semi-floating metal 20. A groove that communicates with the opening of the outer peripheral surface of the metal 20 is formed. Similarly, on the outer peripheral surface of the semi-floating metal 20 where the four oil holes 20c are provided, the inlet end of the oil hole 20c (the semi-hole in the oil hole 20c) extends in the circumferential direction of the semi-floating metal 20. A groove communicating with the opening of the outer peripheral surface of the floating metal 20 is formed. The lubricating oil supplied from the lubricating oil supply unit 21 reaches all the oil holes 20b and 20c through this groove, and flows into the inner peripheral surface side of the semi-floating metal 20 from each oil hole 20b and 20c.

  Further, the inner peripheral surface of the semi-floating metal 20 on the turbine impeller 8 side holds an oil film between the turbine shaft 7 and the diameter of the turbine shaft 7 by the oil film pressure. It is a radial bearing surface 20d (sliding surface) that receives a load in the direction.

  Similarly, the inner peripheral surface of the semi-floating metal 20 on the compressor impeller 9 side holds an oil film with the turbine shaft 7 by the lubricating oil flowing from the oil hole 20c, and the oil film pressure causes the turbine shaft 7 to A radial bearing surface 20e (sliding surface) that receives a load in the radial direction is formed. Both radial bearing surfaces 20 d and 20 e are separated in the axial direction of the turbine shaft 7.

  Further, the semi-floating metal 20 is provided with a pin hole 20 f penetrating in a direction perpendicular to the axial direction of the turbine shaft 7. The bearing housing 2 is formed with a screw hole 2b penetrating from the radially outer side to the inner side of the bearing hole 2a and facing the pin hole 20f of the semi-floating metal 20 accommodated in the bearing hole 2a.

  The pin 22 is partially threaded, screwed into the screw hole 2 b, and the tip side is inserted into the pin hole 20 f of the semi-floating metal 20. In this way, the semi-floating metal 20 is restricted in the rotational direction and axial movement of the turbine shaft 7 with respect to the bearing hole 2a.

  Further, the turbine shaft 7 is provided with a stepped portion 7a. The stepped portion 7a is formed such that the outer diameter of the portion on the turbine impeller 8 side is larger and the outer diameter of the portion on the compressor impeller 9 side is smaller than the inner diameter of the insertion hole 20a on the end surface 20g of the semi-floating metal 20 on the turbine impeller 8 side. Is the stage. The turbine shaft 7 can be inserted into the insertion hole 20a up to a position where the end surface 20g of the semi-floating metal 20 abuts on a surface 7b perpendicular to the axial direction of the turbine shaft 7 due to the outer diameter difference of the stepped portion 7a.

  The oil draining member 23 has a hole 23 a penetrating in the axial direction of the turbine shaft 7. The turbine shaft 7 is inserted into the hole 23 a and is fixed to the turbine shaft 7 so as to be adjacent to the back surface of the compressor impeller 9. . The oil draining member 23 rotates integrally with the turbine shaft 7, and the lubricating oil leaked from the bearing housing 2 is scattered in the radial direction by the centrifugal force generated by the rotation of the turbine shaft 7, and the lubricating oil reaches the back surface of the compressor impeller 9. Prevent reaching.

  In the turbine shaft 7, another step portion 7 c is provided on the compressor impeller 9 side from the step portion 7 a. The stepped portion 7c is formed such that the outer diameter of the portion on the turbine impeller 8 side is larger and the outer diameter of the portion on the compressor impeller 9 side is smaller than the inner diameter of the hole 23a in the end surface 23b on the turbine impeller 8 side of the oil draining member 23. It is a step.

  The oil draining member 23 can insert the turbine shaft 7 up to a position where the end surface 23b comes into contact with a surface 7d perpendicular to the axial direction of the turbine shaft 7 due to a difference in outer diameter of the stepped portion 7c.

  Here, the assembly process of the semi-floating metal 20 and the turbine shaft 7 will be briefly described. In the assembly process, first, the semi-floating metal 20 is fixed to the bearing hole 2 a of the bearing housing 2. In this state, the turbine shaft 7 with the turbine impeller 8 fixed to the front end portion is inserted from the rear end portion into the insertion hole 20a of the semi-floating metal 20. The turbine shaft 7 is inserted through the insertion hole 20a of the semi-floating metal 20 until the end surface 20g of the semi-floating metal 20 on the turbine impeller 8 side contacts the surface 7b of the stepped portion 7a.

  Then, the oil draining member 23 is inserted from the rear end portion of the turbine shaft 7 protruding to the compressor impeller 9 side of the bearing hole 2a. The oil draining member 23 can be inserted into the insertion hole 20a until the end surface 23b on the semi-floating metal 20 side of the oil draining member 23 comes into contact with the surface 7d of the stepped portion 7c of the turbine shaft 7, and at this position, the turbine shaft 7 Fixed to.

  At this time, the distance between the surface 7b of the stepped portion 7a and the end surface 23b of the oil draining member 23 is designed to be slightly larger than the axial length of the semi-floating metal 20. Thus, when the turbine shaft 7 moves in the axial direction, the end surface 20g of the semi-floating metal 20 on the turbine impeller 8 side comes into surface contact with the surface 7b of the stepped portion 7a of the turbine shaft 7, or the compressor impeller of the semi-floating metal 20 The end surface 20 h on the 9 side is in surface contact with the end surface 23 b of the oil draining member 23.

  That is, the semi-floating metal 20 receives a thrust load of the turbine shaft 7 via the stepped portion 7a and the oil draining member 23. In other words, the end surfaces 20g and 20h function as a thrust bearing surface that receives a thrust load.

  3 is an explanatory diagram for explaining the semi-floating metal 20, FIG. 3 (a) is an extraction diagram of the semi-floating metal 20 in FIG. 2, and FIG. 3 (b) is a diagram of FIG. 3 (a). FIG. 3 is a sectional view taken along line III (b) -III (b).

  The semi-floating metal 20 is provided with a plurality of guide grooves 24a and 24b. The guide grooves 24 a and 24 b are portions that are recessed in the radial direction of the turbine shaft 7 from the inner peripheral surface of the semi-floating metal 20, and extend in the axial direction of the turbine shaft 7.

  As shown in FIG. 3A, the guide groove 24a is a groove formed in the radial bearing surface 20d, and the guide groove 24b is a groove formed in the radial bearing surface 20e. Four guide grooves 24 a and 24 b are provided at equal intervals in the circumferential direction of the semi-floating metal 20.

  An end portion on the inner peripheral surface side of the oil hole 20b communicates with a guide groove 24a formed on the radial bearing surface 20d, and an end portion on the inner peripheral surface side of the oil hole 20c is connected to the radial bearing surface 20e. It communicates with the formed guide groove 24b.

  And the guide groove 24a provided in the radial bearing surface 20d is formed so as to extend along the axial direction of the turbine shaft 7 of the radial bearing surface 20d, and from the end on the inner peripheral surface side of the oil hole 20b, The semi-floating metal 20 extends to the tapered surface 20i provided on the axial end surface 20g of the turbine shaft 7. The taper surface 20i is a surface generated by chamfering on the end surface 20g side of the bearing hole 2a.

  Further, the guide groove 24b provided in the radial bearing surface 20e is formed so as to extend along the axial direction of the turbine shaft 7 of the radial bearing surface 20e, and from the end on the inner peripheral surface side of the oil hole 20c, The semi-floating metal 20 extends to the tapered surface 20j provided on the axial end surface 20h of the turbine shaft 7. The tapered surface 20j is a surface generated by chamfering on the end surface 20h side of the bearing hole 2a.

  The guide groove 24a is formed leaving the radial bearing surface 20d in the direction in which the two radial bearing surfaces 20d and 20e are closer to the oil hole 20b (on the center side of the semi-floating metal 20). Similarly, the guide groove 24b is formed leaving the radial bearing surface 20e in the direction in which the two radial bearing surfaces 20d and 20e are closer to each other than the oil hole 20c.

  As described above, when the lubricating oil is guided to the radial bearing surface 20d through the oil hole 20b, the lubricating oil flows toward the end surface 20g while lubricating the radial bearing surface 20d. Further, when the lubricating oil is guided to the radial bearing surface 20e through the oil hole 20c, the lubricating oil flows toward the end surface 20h while lubricating the radial bearing surface 20e. A part of the lubricating oil also flows to the center side of the semi-floating metal 20.

  The semi-floating metal 20 is provided with an oil drain hole 20k communicating with the insertion hole 20a of the semi-floating metal 20 between the radial bearing surfaces 20d and 20e, and the bearing housing 2 includes the oil drain hole 20k. The vertical hole 2c (refer FIG. 2) is provided in the position which opposes. The lubricating oil that has flowed to the center side of the semi-floating metal 20 is discharged vertically downward through the oil drain hole 20k and the vertical hole 2c.

  The guide grooves 24a and 24b promote the flow of the lubricating oil toward the end surfaces 20g and 20h, and thus promote the supply of the lubricating oil to the radial bearing surfaces 20d and 20e.

  At this time, since the radial bearing surfaces 20d and 20e are left on the center side of the semi-floating metal 20 for each of the guide grooves 24a and 24b, the lubricating oil introduced from the oil holes 20b and 20c is in the semi-floating metal 20 respectively. It is difficult to flow toward the center side, and it tends to flow toward the end faces 20g and 20h of the semi-floating metal 20. Therefore, it is possible to increase the amount of lubricating oil supplied to the end faces 20g and 20h that function as thrust bearing surfaces, avoid damage due to lack of oil at the end faces 20g and 20h, and expand the range of usable load conditions. Become.

  If foreign matter is mixed in the lubricating oil, the foreign matter is discharged to the end faces 20g and 20h (outside the insertion hole 20a of the semi-floating metal 20) through the guide grooves 24a and 24b.

  FIG. 4 is an explanatory diagram for explaining the flow of foreign matter in the guide groove. FIG. 4A shows a cross-sectional view of the semi-floating metal 20 and the turbine shaft 7 in this embodiment, and FIG. Sectional drawing of the semi floating metal M and the turbine shaft T in a comparative example is shown. However, in order to facilitate understanding, in FIG. 4, with respect to a cross section perpendicular to the turbine shaft, hatching indicating the cross section is omitted, and the vicinity of a portion where one guide groove is provided is enlarged.

  As shown in FIG. 4 (b), the guide groove A of the comparative example has a semicircular cross-sectional shape, and the rotational direction of the turbine shaft T (see FIG. 4) in a portion continuous with the guide groove A on the radial bearing surface S. The angle α ′ formed by the tangent line a ′ of the front portion (shown by the white arrow in FIG. 4B) and the tangent line b ′ of the wall portion W on the front side in the rotational direction of the turbine shaft 7 that defines the guide groove A. Is over 90 degrees. In this case, the foreign matter m flows under the influence of the lubricating oil flow in the rotational direction of the turbine shaft T. Since the guide groove A continues to the gap (bearing gap) between the turbine shaft T and the radial bearing surface S with a gentle inclination, the foreign matter m jumps out of the guide groove A and is caught in the bearing gap. There is a risk that. In particular, when the size of the foreign matter m is equal to or smaller than the bearing gap, the foreign matter m is easily caught.

  Therefore, in the present embodiment, the shape of the guide grooves 24a and 24b is devised, and the foreign matter holding part 25 is provided. The foreign matter holding part 25 has a function of holding the foreign matter m mixed in the lubricating oil flowing into the guide grooves 24a and 24b in the guide grooves 24a and 24b.

  Specifically, the foreign matter holding part 25 is constituted by a part of the guide groove 24a, and as shown in FIG. 4A, the turbine shaft 7 of the wall part of the semi-floating metal 20 that forms the guide groove 24a. The wall portion 20l on the front side (right side in FIG. 4) of the rotation direction (indicated by a white arrow in FIG. 4A). Further, the wall portion 201 on the front side in the rotational direction of the turbine shaft 7 that defines and forms the foreign object holding portion 25 is a curved surface that is curved in an arc shape.

  Further, as shown in FIG. 4A, the tangent line a of the portion continuous with the wall portion 20l on the front side in the rotational direction of the turbine shaft 7 in the portion continuous with the guide groove 24a in the radial bearing surface 20d and the foreign matter holding Of the angles α and β formed by the tangent line b of the wall portion 20l on the front side in the rotational direction of the turbine shaft 7 that defines the section 25, the angle α on the front side in the rotational direction of the turbine shaft 7 from the wall portion 201 is 90 Less than or equal to degrees.

  Even if the foreign matter m that has entered the guide groove 24a is likely to jump out from the front side in the rotational direction of the guide groove 24a, the foreign matter holding part 25 makes a vortex as shown by an arrow c shown in FIG. . Therefore, it becomes difficult for the foreign matter m to jump out of the guide groove 24a, and the biting of the foreign matter m into the bearing gap can be suppressed. The foreign matter m is discharged from the end face 20g by being held by the foreign matter holding portion 25 without jumping out from the guide groove 24a.

  Here, the foreign object holding part 25 provided in the guide groove 24a on the turbine impeller 8 side has been described, but the foreign object holding part 25 is similarly provided in the guide groove 24b on the compressor impeller 9 side.

(Modification)
FIG. 5 is an explanatory diagram for explaining the guide grooves 34a and 44a in the modified example. FIG. 5A shows a cross-sectional view of the semi-floating metal 30 and the turbine shaft 7 in the first modified example, and FIG. b) shows a sectional view of the semi-floating metal 40 and the turbine shaft 7 in the second modification. However, in FIG. 5, with respect to the cross section perpendicular to the turbine shaft 7, hatching indicating the cross section is omitted, and the vicinity of the portion where the one guide groove 34 a, 44 a is provided is shown enlarged, and the rotation direction of the turbine shaft 7 is shown in white. Shown with a blank arrow.

  Also in the first modification, as in the first embodiment described above, the tangent line a of the portion of the radial bearing surface 30d that is continuous with the guide groove 34a and the portion on the front side in the rotational direction of the turbine shaft 7 and the foreign matter holding portion Among the angles α and β formed by the extension line b of the wall portion 30l on the front side in the rotational direction of the turbine shaft 7 that defines the section 35, the angle α on the front side in the rotational direction of the turbine shaft 7 from the wall portion 30l is 90 Less than or equal to degrees.

  As shown in FIG. 5A, the foreign substance holding part 35 in the first modification has a flat wall part 30l on the front side in the rotational direction of the turbine shaft 7 that defines the foreign substance holding part 35. As described above, even if the wall portion 30l is flat, the foreign matter m is held in the guide groove 34a by the foreign matter holding portion 35. Therefore, the foreign matter m is difficult to jump out of the guide groove 34a, and the foreign matter m enters the bearing gap. Biting can be suppressed.

  However, like the guide groove 24a of the first embodiment described above, the wall portion 20l is configured by a curved surface, so that the foreign matter m can be easily swirled and circulated, and the foreign matter m is more difficult to jump out of the guide groove 34a. It becomes possible to make it.

  Also in the second modified example shown in FIG. 5B, as in the first embodiment described above, the portion of the radial bearing surface 40d that is continuous with the guide groove 44a is the portion on the front side in the rotational direction of the turbine shaft 7. Of the angles α and β formed by the tangent line a and the tangent line b of the wall portion 40l on the front side in the rotational direction of the turbine shaft 7 that defines and forms the foreign substance holding portion 45, the front side in the rotational direction of the turbine shaft 7 from the wall portion 401 The angle α is 90 degrees or less. Further, the wall portion 40l on the front side in the rotational direction of the turbine shaft 7 that defines the foreign substance holding portion 45 is a curved surface that is curved in an arc shape.

  Then, the guide groove 44a in the second modified example is a boundary that is a surface that is the center of the guide groove 44a in the rotation direction of the turbine shaft 7 (in FIG. 5B, the center surface d is indicated by a one-dot chain line). The shape of the turbine shaft 7 on the front side in the rotational direction and the shape on the rear side in the rotational direction are symmetrical. That is, the guide groove 44 a is line symmetric with respect to the broken line d, and the foreign matter holding part 45 is also formed on the rear side in the rotational direction of the turbine shaft 7. Here, the surface d is an imaginary surface including any two points located at the center of the turbine shaft 7 in the rotation direction of the guide groove 44 a and the axis of the turbine shaft 7. However, it is assumed that the axis of the turbine shaft 7 is not located on a straight line passing through any two points located at the center of the turbine shaft 7 in the rotational direction. That is, the surface d is a surface that bisects the guide groove 44a into a front side and a rear side in the rotational direction of the turbine shaft 7.

  Therefore, not only the front side in the rotation direction but also the rear side in the rotation direction makes it easy for the foreign matter m to circulate and flow back, making it difficult for the foreign matter m to jump out of the guide groove 44a.

(Second Embodiment)
In the first embodiment described above, the case where the semi-floating metal 20 is provided has been described, but in the second embodiment, a configuration in which biting by the foreign matter m is suppressed in the case where the full floating metal is provided will be described.

  FIG. 6 is an explanatory diagram for explaining the bearing structure in the second embodiment, and is a cross-sectional view in the vicinity of the bearing hole 50a of the bearing housing 50 in the second embodiment.

  As shown in FIG. 6, two full floating metals 51 and 52 are provided in the bearing hole 50a. The full floating metal 51 is arranged on the turbine impeller 8 side (left side in FIG. 6) in the bearing hole 50a, and the full floating metal 52 is arranged on the compressor impeller 9 side (right side in FIG. 6).

  The full floating metals 51 and 52 are pivotally supported by inserting the turbine shaft 53 through the annular main bodies 51a and 52a, respectively. The full floating metal 51 disposed on the turbine impeller 8 side is sandwiched between the two rings 54 a and 54 b from the front and rear in the axial direction of the turbine shaft 53, and the axial movement of the turbine shaft 53 is restricted.

  Further, the full floating metal 52 arranged on the compressor impeller 9 side is sandwiched between the ring shaft 54c from the front side (left side in FIG. 6) of the turbine shaft 53 and the thrust bearing 56a from the rear side (right side in FIG. 6). Thus, the axial movement of the turbine shaft 53 is restricted.

  The thrust bearing 56a faces the turbine impeller 8 side with respect to the thrust collar 57 fixed to the compressor impeller 9 side of the turbine shaft 53, and the thrust bearing 56b faces the compressor impeller 9 side with respect to the thrust collar 57. Both thrust bearings 56a and 56b receive axial loads of the turbine shaft 53, respectively.

  The lubricating oil supply unit 58 is configured to include a hole communicating from the outside of the bearing housing 50 to the bearing hole 50a and the thrust bearing 56b, and from the outside of the bearing housing 50 to the bearing hole 50a and the thrust bearings 56a and 56b. Supply lubricating oil.

  The bearing housing 50 is provided with a vertical hole 50b that communicates with the bearing hole 50a and opens vertically downward. A part of the lubricating oil supplied to the full floating metals 51 and 52 by the lubricating oil supply unit 58 is lubricated to the full floating metals 51 and 52 and then discharged vertically downward through the vertical holes 50b.

  Further, the lubricating oil supplied to the full floating metals 51 and 52 is also discharged from both ends of the bearing hole 50a in the axial direction of the turbine shaft 53, and the lubricating oil discharged to the compressor impeller 9 side of the bearing hole 50a is The thrust bearings 56a and 56b are lubricated and discharged vertically downward.

  FIG. 7 is an explanatory diagram for explaining the full floating metal 51, FIG. 7A shows the VII (a) arrow of FIG. 6 about the full floating metal 51, and FIG. FIG. 7 is a sectional view taken along line VII (b) -VII (b) in FIG.

  Since the full floating metal 51 and the full floating metal 52 have substantially the same structure, the full floating metal 51 will be described here, and the description of the full floating metal 52 will be omitted.

  As shown in FIG. 7, between the outer peripheral surface 51b of the full floating metal 51 and the bearing hole 50a, the lubricating oil supplied by the lubricating oil supply unit 58 is circulated. It is rotatably supported by the oil film pressure between 51b and the bearing hole 50a.

  Moreover, as shown in FIG.7 (b), the full floating metal 51 has the oil hole 51c penetrated to the radial direction of the main body 51a. For example, four oil holes 51c are provided at equal intervals in the circumferential direction of the main body 51a, and a part of the lubricating oil supplied to the bearing holes 50a by the lubricating oil supply unit 58 is transferred to the outer peripheral surface 51b (slip surface) of the main body 51a. ) Side to the inner peripheral surface 51d (slip surface) side.

  Between the inner peripheral surface 51 d of the full floating metal 51 and the turbine shaft 53, the lubricating oil supplied by the lubricating oil supply unit 58 circulates, and the full floating metal 51 has the inner peripheral surface 51 d and the turbine shaft 53. The turbine shaft 53 is rotatably supported by the oil film pressure between the two.

  The full floating metal 51 rotates at a lower speed than the turbine shaft 53 due to the flow of lubricating oil accompanying the rotation of the turbine shaft 53. That is, the full floating metal 51 rotates relative to the bearing hole 50a without contact.

  Further, four guide grooves 51 e are provided on the inner peripheral surface 51 d of the full floating metal 51 at equal intervals in the circumferential direction of the full floating metal 51. The guide groove 51e is a portion that is recessed in the radial direction of the turbine shaft 53, and is formed so as to extend along the axial direction of the turbine shaft 53 (the axial center direction of the main body 51a). The shaft 53 extends to tapered surfaces 51h and 51i provided on both end surfaces 51f and 51g in the axial direction.

  The tapered surfaces 51h and 51i are surfaces generated by chamfering on both end surfaces 51f and 51g of the bearing hole 50a. The end of the oil hole 51c on the inner peripheral surface 51d side communicates with the guide groove 51e.

  FIG. 8 is a cross-sectional view of the full floating metal 51 and the turbine shaft 53. However, in FIG. 8, the hatching which shows a cross section is abbreviate | omitted about the cross section perpendicular | vertical to the turbine shaft 53, and the part vicinity provided with one guide groove 51e is expanded and shown.

  As shown in FIG. 8, the full floating metal 51 is provided with a foreign matter holding part 55. The foreign substance holding part 55 has a function of holding the foreign substance m mixed in the lubricating oil flowing into the guide groove 51e in the guide groove 51e, like the foreign substance holding part 25 of the first embodiment.

  Specifically, the foreign material holding part 55 is a part of the guide groove 51e, and of the wall part of the full floating metal 51 that forms the guide groove 51e, the front side in the rotational direction of the turbine shaft 53 (in FIG. 8, (Right side) wall 51l.

  Further, the wall portion 51l on the front side in the rotational direction of the turbine shaft 53 that defines and forms the foreign material holding portion 55 is a curved surface that is curved in an arc shape. Further, of the portion of the inner peripheral surface 51d that is continuous with the guide groove 51e, the tangent a of the portion on the front side in the rotational direction of the turbine shaft 53 and the wall on the front side in the rotational direction of the turbine shaft 53 that defines and forms the foreign matter holding portion 55. Of the angles α and β formed by the tangent line b of the part 51l, the angle α on the front side in the rotational direction of the turbine shaft 7 from the wall part 51l is 90 degrees or less.

  As described above, even when the foreign matter holding portion 55 is provided in the full floating metal 51, the foreign matter m that has entered the guide groove 51e spirals as indicated by the arrow c, as in the first embodiment described above. Therefore, the foreign matter m can be prevented from being caught in the bearing gap.

  Further, in the foreign substance holding part 55 of the full floating metal 51, the wall part on the front side in the rotational direction of the turbine shaft 53 that defines and forms the foreign substance holding part 55 may be a plane. However, when the wall portion is formed of a curved surface, the foreign matter m can be easily circulated and refluxed, and the foreign matter m can be more difficult to jump out of the guide groove 51e.

  Also, the guide groove 51e of the full floating metal 51 has a shape on the front side in the rotational direction of the turbine shaft 53, with the surface of the guide groove 51e being the center in the rotational direction of the turbine shaft 53 as in the second modification. The shape on the rear side in the rotational direction may be symmetric. In the case of the full floating metal 51 as well as in the case of the semi-floating metal 20, not only the front side in the rotation direction but also the rear side in the rotation direction makes it easy for the foreign matter m to circulate and return to the guide groove 51e. It is possible to make it more difficult to jump out of the.

  In the second embodiment described above, the case where the guide groove 51e is provided on the inner peripheral surface 51d of the full floating metal 51 has been described. However, the bearing of the bearing housing 50 (supercharger main body) in which the full floating metal 51 is disposed. A guide groove may be provided on the inner peripheral surface (slip surface) of the hole 50a. In this case, the foreign substance holding portion is provided on the wall portion of the bearing hole 50 a of the bearing housing 50.

  That is, the guide groove is formed on one or both of the sliding surface of the full floating metal 51 that pivotally supports the turbine shaft 53 and the sliding surface of the bearing hole 50a that holds the full floating metal 51. Of the full floating metal 51 forming the guide groove or the wall portion of the bearing housing 50, the full floating metal 51 may be formed by a wall portion on the front side in the rotational direction.

  In any case, the foreign matter m becomes difficult to jump out of the guide groove by the foreign matter holding portion, and the biting of the foreign matter m can be suppressed. In particular, the guide groove is provided on the sliding surface formed on the inner peripheral surface, so that the foreign matter m is pressed against the bottom surface of the guide groove by centrifugal force. It becomes possible.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  The present invention can be used for a supercharger in which lubricating oil is supplied to a bearing hole.

C ... supercharger 1 ... supercharger body 2a, 50a ... bearing hole 7, 53 ... turbine shaft 8 ... turbine impeller 9 ... compressor impeller 20,30,40 ... semi-floating metal 20a ... insertion hole 20b, 20c ... oil hole 20d, 20e, 30d, 40d ... Radial bearing surface (sliding surface)
20g, 20h ... End faces 20l, 30l, 40l, 51l ... Walls 24a, 24b, 34a, 44a, 51e ... Guide grooves 25, 35, 45, 55 ... Foreign matter holding parts 51, 52 ... Full floating metal 51d ... Inner peripheral surface (Slip surface)

Claims (5)

A turbocharger body;
A bearing hole formed in the supercharger body;
A turbine shaft rotatably accommodated in the bearing hole, provided with a turbine impeller at one end and a compressor impeller at the other end;
Two sliding surfaces that are spaced apart in the axial direction of the turbine shaft and pivotally support the turbine shaft; and an oil hole that penetrates from the radially outer side of the sliding surface to the sliding surface and guides lubricating oil to the sliding surface; And a guide groove formed in the two sliding surfaces and extending in the axial direction of the turbine shaft to circulate the lubricating oil , and is accommodated in the bearing hole, and the turbine shaft is accommodated in the bearing hole. a semi-floating metal movement in the axial direction and the rotational direction is regulated,
With
The guide groove is
Of the semi-floating metal walls that form the guide groove, foreign matter that is formed by the wall portion on the front side in the rotational direction of the turbine shaft and enters the lubricating oil flowing into the guide groove It has a foreign object holding section for holding the,
From the oil hole extending to the end face in the axial direction of the turbine shaft of the semi-floating metal, in the direction in which the two sliding surfaces come close than oil holes, Ru is formed to leave the sliding surface A turbocharger characterized by that.   Of the angle formed by the tangent of a portion of the sliding surface that is continuous with the wall portion on the front side in the rotational direction of the turbine shaft and the wall portion on the front side in the rotational direction of the turbine shaft that forms the foreign matter holding portion The supercharger according to claim 1, wherein an angle of the turbine shaft from the front side in the rotational direction of the turbine shaft is 90 degrees or less.   The supercharger according to claim 1 or 2, wherein a wall portion on the front side in the rotational direction of the turbine shaft that forms the foreign matter holding portion is a curved surface that is curved in an arc shape. The guide groove is
The shape on the front side in the rotation direction of the turbine shaft and the shape on the rear side in the rotation direction are symmetrical with respect to a plane that is the center in the rotation direction of the turbine shaft in the guide groove. The supercharger of any one of 1-3. The semi-floating metal is,
Provided on the end face in the axial direction of the front Symbol turbine shaft, the thrust bearing surface for receiving a thrust load
Turbocharger according to claim 1, any one of 4, wherein Rukoto equipped with.

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