JP2007023858A - Bearing structure for turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing structure for a turbocharger capable of improving cooling effect and lubricating effect at the inside and outside of a bearing by inhibiting rise of temperature of oil. <P>SOLUTION: In a turbocharger 1 provided with a housing 1a provided with a bearing hole 18 through which a turbine shaft 23 passes and a pin hole 21 extending from an outer circumference surface 17a to the bearing hole 18, and a bearing 20 fitted in the bearing hole 18, a positioning pin 22 to be fitted in the pin hole 21 in such a manner that one end there of is fitted in the bearing 20 and another end thereof reaches an opening part in an outer circumference surface side of the pin hole 21. An oil passage 22d passing through the positioning pin 22 in an axial direction is provided inside of the positioning pin 22. Oil introduction parts 27, 28 are provided between an inner circumference surface of the bearing 20 and the turbine shaft 23, and between an outer circumference surface of the bearing 20 and the bearing hole 18. An oil hole 20c penetrating through the bearing 20 in a radial direction is provided on the bearing to establish communication between inside and outside oil introduction part 27, 28. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a turbine shaft bearing structure in a turbocharger.

  As a bearing structure for a turbine shaft incorporated in a turbocharger of an internal combustion engine, a bearing that supports the turbine shaft is fitted into a bearing hole provided in the turbocharger housing, and the bearing is supported radially from the outside of the housing. The bearing pin is inserted to prevent rotation of the bearing, and the bearing lubricating oil is sequentially passed through the housing pin hole in which the positioning pin is fitted and the oil hole formed in the positioning pin. There is known a bearing structure that guides the oil in the oil reservoir to the oil reservoir in the outer peripheral portion of the bearing through a radial through hole formed in the bearing (for example, patent) Reference 1). In addition, there is Patent Document 2 as a prior art document related to the present invention.

Japanese Patent No. 3365209 Japanese Patent Publication No. 7-74612

  In the conventional bearing structure, the positioning pin is fitted back in the pin hole rather than the outer peripheral surface of the housing, and the oil supplied from the outside of the housing is in contact with the inner peripheral surface of the pin hole of the housing, It is introduced into the hole. Therefore, the oil receives heat from the housing, and as a result, the cooling effect or the lubricating effect on the inner and outer periphery of the bearing by the oil may be impaired.

  Accordingly, an object of the present invention is to provide a turbocharger bearing structure capable of suppressing the temperature rise of oil and enhancing the cooling effect or lubrication effect inside and outside the bearing.

  A turbocharger bearing structure according to the present invention includes a housing provided with a bearing hole through which a turbine shaft passes and a pin hole extending from an outer peripheral surface to the bearing hole, a bearing fitted into the bearing hole, and one end thereof. An oil passage that fits into the bearing and is fitted into the pin hole so that the other end reaches the opening on the outer peripheral surface side of the pin hole and extends in the axial direction from the one end to the other end is provided inside. Positioning pins, and oil introduction portions are provided between the inner peripheral surface of the bearing and the turbine shaft and between the outer peripheral surface of the bearing and the bearing hole, respectively, The above-described problem is solved by providing an oil hole penetrating the bearing in the radial direction so as to communicate with the oil introduction portion on the inner and outer circumferences of the bearing (Claim 1).

  According to the bearing structure of the turbocharger of the present invention, the positioning pin reaches the opening of the pin hole on the outer peripheral surface side of the housing, so that the oil passage of the positioning pin can be passed from the outside of the housing without passing through the pin hole. Oil can be introduced directly, the oil can be led to the oil introduction part on the inner circumference of the bearing through the oil passage, and the oil can be led to the oil introduction part on the outer circumference of the bearing through the oil hole of the bearing . Accordingly, it is possible to prevent the oil temperature from rising due to the contact between the inner peripheral surface of the pin hole of the housing and the oil, and to reliably introduce the low temperature oil to the inner and outer periphery of the bearing, thereby enhancing the cooling effect or the lubricating effect.

  In one embodiment of the present invention, a gap may be provided between an inner peripheral surface of the pin hole of the housing and an outer peripheral surface of the positioning pin fitted in the pin hole (Claim 2). According to this embodiment, since the gap is provided between the housing and the positioning pin, heat transfer from the housing to the positioning pin is suppressed, thereby further effectively increasing the temperature of the oil passing through the oil passage of the positioning pin. Can be suppressed.

  In one embodiment of the present invention, a head portion protruding from the outer peripheral surface of the housing may be provided at the other end of the positioning pin, and the head portion may be fixed to the outer peripheral surface of the housing using a fixing means. (Claim 3). According to this aspect, by fixing the positioning pin to the outer peripheral surface of the housing, it is not necessary to press the positioning pin into the pin hole and to prevent the positioning pin from being seized. Therefore, there is no possibility that the wall surface of the pin hole will be gnawed when the positioning pin is fitted into the pin hole, and there is no possibility that foreign matters derived from the attachment of the positioning pin will be mixed around the bearing.

  In one embodiment of the present invention, both end surfaces of the bearing are configured as thrust bearings, and the turbine shaft is arranged on the inner peripheral surface of the bearing from the oil introduction portion of the inner periphery of the bearing toward both end sides of the bearing. A spiral oil groove extending from the oil introduction portion on the inner periphery of the bearing to the both end surfaces may be provided while being gradually displaced forward in the rotation direction. According to this aspect, the deviation between the direction of the oil velocity vector and the direction of the oil groove when the turbine shaft is rotating is reduced as compared with the case where the oil groove is formed straight in the direction of the turbine axis. Therefore, the oil can be efficiently guided from the oil introduction portion on the inner periphery of the bearing to both end faces of the bearing through the oil groove. As a result, a sufficient amount of oil can be introduced into the thrust bearing portions on both end faces of the bearing to form a necessary and sufficient oil film.

  In the form in which the oil groove is provided on the inner peripheral surface of the bearing, the both end surfaces of the bearing are provided with tapered portions in which the depth in the turbine axis direction gradually decreases toward the rotation direction of the turbine shaft relative to the bearing, The oil groove may communicate with the tapered portion. According to this aspect, oil flows from the oil groove into the taper portion, and the oil in the thrust direction between the taper portion and the bearing end surface and the turbine shaft or a rotating part that rotates integrally with the turbine shaft rotates as the turbine shaft rotates. Smoothly flows into the gap. Thereby, an oil film can be more smoothly and easily formed on both end faces of the bearing.

  As described above, according to the turbocharger bearing structure of the present invention, the bearing to be supplied through the oil passage in the positioning pin without bringing the oil to be supplied around the bearing into contact with the pin hole of the housing. Since the oil can be guided to the oil introduction part on the inner and outer circumferences of the shaft, the temperature rise of the oil due to the heat of the housing can be suppressed, and the low temperature oil can be supplied to the inside and outside of the bearing to enhance the lubrication effect or the cooling effect.

  FIG. 1 shows an embodiment in which the present invention is applied to a turbocharger of an automobile internal combustion engine. The turbocharger 1 includes an exhaust turbine section 2, a compressor section 3, a rotating electrical machine section 4 disposed between them, and a bearing section 5. The exhaust turbine section 2 includes a turbine housing 6 provided so as to constitute a part of an exhaust passage of the internal combustion engine, and a turbine 7 provided inside the turbine housing 6. On the other hand, the compressor unit 3 includes a compressor housing 8 provided so as to constitute a part of the intake passage of the internal combustion engine, and an impeller (compressor impeller) 9 provided inside the compressor housing 8. The rotating electrical machine unit 4 is provided to generate a rotational force that supplements the rotation of the turbine 7 or to generate power using the rotation of the turbine 7, and closes the motor housing 10 and the opening of the motor housing 10. A seal plate 11, a stator 12 disposed in the motor housing 10, a coil winding portion 13, and a rotor 14 are provided.

  The motor housing 10 and the seal plate 11 are combined with the compressor housing 8 so as to close the opening of the compressor housing 8. The flange 10a of the motor housing 10 is superimposed on the seal plate 11, and a plurality of bolts 15 and washers 16 are attached to the compressor housing 8 so as to hold down the flange 10a. Are connected to each other.

  The bearing unit 5 is formed in a bearing housing 17 disposed between the exhaust turbine unit 2 and the rotating electrical machine unit 4, a bearing 20 fitted in the bearing hole 18 of the bearing housing 17, and a pin hole 21 of the bearing housing 17. And positioning pins 22 to be fitted together. The bearing housing 17 and the turbine housing 6 are coupled to each other by a fastening band 19. The turbocharger housing 1a is configured by combining the turbine housing 6, the bearing housing 17, the motor housing 10, the seal plate 11, and the compressor housing 8. The configuration of the supercharger housing 1a is not limited to the illustrated form, and may be changed as appropriate. Details of the bearing 20 and the positioning pin 22 will be described later.

  A turbine shaft 23 is provided at one end of the turbine 7 so as to be integrally rotatable and not separable in the axial direction. The turbine shaft 23 is provided with a large diameter portion 23a, an intermediate shaft portion 23b, and a small diameter portion 23c in order from the turbine 7 side. The large diameter portion 23 a is abutted against the end surface 20 a of the bearing 20 on the turbine 7 side. The intermediate shaft portion 23 b extends through the bearing hole 18 of the bearing housing 17, more specifically, the inside of the bearing 20 fitted in the bearing hole 18 to the end surface 20 b on the impeller side of the bearing 20. The small diameter portion 23 c extends through the rotating electrical machine portion 4 to the inside of the compressor housing 8. A thrust collar 24 is fitted to the outer periphery of the small diameter portion 23c so as to be integrally rotatable, and the rotor 14 and the impeller 9 are sequentially fitted to the tip of the thrust collar 24. The impeller 9 is fastened in the axial direction by a nut 25 screwed into the tip of the small diameter portion 23c. As a result, the turbine shaft 23, the thrust collar 24, the rotor 14, the impeller 9 and the nut 25 are combined so as to be integrally rotatable, and the rotating part assembly 26 of the turbocharger 1 is constituted by these rotating parts and the turbine 7. Is done. The bearing 20 is sandwiched between the large diameter portion 23 a of the turbine shaft 23 and the thrust collar 24. Thus, both end surfaces 20 a and 20 b of the bearing 20 function as a thrust bearing that supports the rotating body assembly 26 in the axial direction of the turbine shaft 23. That is, in the bearing 20, a radial bearing for supporting the turbine shaft 23 and thus the rotating body assembly 26 in the radial direction and a thrust bearing for supporting the rotating body assembly 26 in the axial direction of the turbine shaft 23 are integrated. It has a structure. When such a bearing 20 is used, there exists an advantage which can shorten the full length of the rotary body assembly 26. FIG.

  As shown in detail in FIG. 2, the positioning pin 22 passes through the head portion 22a, the intermediate portion 22b following the head portion 22a, the tip portion 22c having a smaller diameter than the intermediate portion 22b, and the positioning pin 22 in the axial direction. And an oil passage 22d. The head portion 22 a is provided with a flange 22 e that abuts on a pin mounting seat surface 17 a formed on the outer peripheral surface of the bearing housing 17. A pipe connection portion 22f connected to an oil pipe (not shown) is provided at the end of the oil passage 22d on the head portion 22a side.

  The pin hole 21 of the bearing housing 17 is formed by combining a large-diameter portion 21 a that opens to the pin mounting seat surface 17 a and a small-diameter portion 21 b that is coaxially connected to the large-diameter portion 21 a and opens to the bearing hole 18. It is formed as a through hole extending from the pin mounting seat surface 17 a as a part of the outer peripheral surface of the feeder housing 1 a to the bearing hole 18. The inner diameter of the large diameter portion 21a is larger than the diameter of the intermediate portion 22b of the positioning pin 22 and smaller than the outer diameter of the flange 22e of the head portion 22a. On the other hand, the inner diameter of the small-diameter portion 21b is set so that the distal end portion 22c of the positioning pin 22 can be fitted with no looseness in the radial direction. However, the fit between the tip portion 22c and the small diameter portion 21b may be a clearance fit. The difference in diameter between the large diameter portion 21a and the intermediate portion 22b is set sufficiently larger than the difference in diameter between the small diameter portion 21b and the tip portion 22c. Further, the bearing 20 is formed with a through hole 20c having the same diameter as the small diameter portion 21b of the pin hole 21.

  The positioning pin 22 is fitted in the pin hole 21 such that the tip 22c passes through the small diameter portion 21b of the pin hole 21 and fits in the through hole 20c of the bearing 20. Thus, the bearing 20 is prevented from rotating in the radial direction, and the bearing 20 is positioned at a fixed position in the supercharger housing 1a in the axial direction of the turbine shaft 23. The head portion 22a of the positioning pin 22 protrudes outside the supercharger housing 1a beyond the opening of the pin hole 21 to the pin mounting seat surface 17a. The flange 22e of the head portion 22a is fixed to the bearing housing 17 by an appropriate fixing means in a state of being abutted against the pin mounting seat surface 17a. As an example, as shown in FIG. 3, the flange 22e of the head portion 22a is somewhat extended in the circumferential direction of the bearing housing 17 (corresponding to the direction orthogonal to the paper surface in FIG. 2) and penetrates the extended portion. Then, the positioning pins 22 are fixed to the bearing housing 17 by screwing bolts 42 as fixing means into the bearing housing 17. According to such an attachment structure, it is not necessary to fix the positioning pin 22 to the inner periphery of the pin hole 21 by using a fastening means such as press fitting or shrink fitting to the pin hole 21. There is no possibility that the wall surface of the pin hole 21 is bitten by the positioning pin 22. As a result, it is possible to eliminate the possibility that foreign matter generated due to the mounting operation of the positioning pin 22 is mixed around the bearing 20.

  Returning to FIG. 2, a gap is generated between the outer periphery of the intermediate portion 22 b of the positioning pin 22 attached as described above and the inner periphery of the large-diameter portion 21 a of the pin hole 21. The gap is closed to the outside of the supercharger housing 1a by the flange 22e of the head portion 22a of the positioning pin 22. Then, by attaching the positioning pin 22 as described above, oil for lubricating the periphery of the bearing 20 is supplied from the outside of the supercharger housing 1a via the oil passage 22d of the positioning pin 22 to the inner periphery of the bearing 20. Can be introduced. In the illustrated embodiment, the tip 22c of the positioning pin 22 reaches almost the same position as the inner peripheral surface of the bearing 20. However, as long as the tip 22c of the positioning pin 22 is fitted in the through hole 20c of the bearing 20, The distal end of the positioning pin 22 may be somewhat retracted toward the outer peripheral side of the inner peripheral surface of the bearing 20.

  Oil reservoir chambers 27 and 28 as oil introduction portions are provided between the inner peripheral surface of the bearing 20 and the turbine shaft 23 and between the outer peripheral surface of the bearing 20 and the bearing hole 18, respectively. The radial clearance of the inner oil reservoir 27 is somewhat larger than that of the outer oil reservoir 28. The oil reservoir 27 on the inner peripheral side communicates with the oil passage 22 d of the positioning pin 22. On the other hand, the oil reservoir chamber 28 on the outer peripheral side communicates with the oil reservoir chamber 27 on the inner peripheral side through an oil hole 20d that penetrates the bearing 20 in the radial direction. Accordingly, the oil introduced into the oil passage 22d of the positioning pin 22 first flows into the oil reservoir 27 on the inner peripheral side, and then flows into the oil reservoir 28 on the outer peripheral side through the oil hole 20d. The oil hole 20d is provided at the same position as the through hole 20c with respect to the axial direction of the turbine shaft 23, and the circumferential direction of the bearing 20 is shifted from the through hole 20c by an appropriate angle, for example, 180 °. However, a plurality of oil holes 20d may be provided by changing the position in the circumferential direction with respect to the through hole 20c. The through hole 20c and the oil hole 20d are set to have the same diameter so that they can be processed with the same drilling tool. However, the inner diameters of the holes 20c and 20d may be different from each other.

  In the region between the oil reservoirs 27, 28 and the both end surfaces 20 a, 20 b of the bearing 20, the inner diameter of the bearing 20 is somewhat larger than the outer diameter of the intermediate shaft portion 23 a of the turbine shaft 23 and the outer diameter of the bearing 20. Is set to be somewhat smaller than the inner diameter of the bearing hole 18 of the bearing housing 17. As a result, some gaps are formed between the inside and outside of the bearing 20 and the turbine shaft 23 and the bearing hole 18 in portions other than the oil reservoirs 27 and 28. When oil enters the gaps from the oil reservoirs 27 and 28 to form an oil film, each of the turbine shaft 23 and the bearing 20 is supported in the radial direction via the oil film. That is, an oil damper structure for the turbine shaft 23 is formed by the bearing 20 and the oil film inside and outside thereof. Further, the oil guided to the gap inside and outside the bearing 20 flows into the gap between the both end faces 20a, 20b of the bearing 20 and the large-diameter portion 23a of the turbine shaft 23 and the thrust collar 24, and the oil film in the thrust direction in these gaps. Form. The oil flowing out from the gap between the bearing 20 and the turbine shaft large diameter portion 23a and the thrust collar 24 is discharged to the outside of the supercharger housing 1a via the drain passage 17b of the bearing housing 17. Note that the amount of oil guided to the inner and outer gaps of the bearing 20 can be appropriately adjusted according to the size and number of the oil holes 20d. Seal rings 40 and 41 for sealing the inside of the turbine housing 6 and the motor housing 10 and the inside of the bearing housing 17 are attached to the outer circumferences of the large-diameter portion 23 a and the thrust collar 24 of the turbine shaft 23.

  As shown in FIG. 4, the inner circumferential surface of the bearing 20 includes a plurality of oil grooves 30 extending from the oil reservoir chamber 27 to the end surface 20 a of the bearing 20 on the turbine 7 side, and the oil reservoir chamber 27 to the bearing 20. A plurality of oil grooves 31 extending to the end surface 20b on the impeller 9 side are provided at intervals in the circumferential direction. These oil grooves 30 and 31 are provided in order to smoothly guide the oil from the oil reservoir chamber 27 to both end surfaces 20a and 20b. The number of oil grooves 30 and 31 is set to 4 each, but the number may be changed as appropriate. FIG. 4 shows the end surface 20b on the impeller side, but the opposite end surface 20a has the same configuration. The oil grooves 30 and 31 may be formed in a linear groove shape extending in parallel with the axial direction of the turbine shaft 23. However, in this embodiment, as shown in FIG. 5, it is inclined with respect to the axial direction of the turbine shaft 23 (left and right direction in FIG. 5). The direction of these inclinations is set so that the turbine shaft 23 gradually displaces forward (in the direction indicated by the arrow Vo in the figure) toward the end surfaces 20a and 20b from the oil reservoir chamber 27. More specifically, when the rotation of the turbine shaft 23 is stopped, the velocity vector of oil flowing from the oil reservoir chamber 27 through the gap between the bearing 20 and the turbine shaft 23 to the end faces 20a, 20b is Va, the turbine shaft. If the speed vector at the time of rotation 23 is Vo, the speed vector Vb of oil when the turbine shaft 23 is rotating is obtained by combining these speed vectors. The oil grooves 30 and 31 are inclined so that their longitudinal directions coincide with the direction of the velocity vector Vb. Since the oil velocity vectors Vb are equal and opposite to each other on the left and right sides of the oil reservoir 27, the oil grooves 30 and 31 are symmetrical with respect to a center line Lc that bisects the oil reservoir 27 in the turbine axial direction. . Further, in FIG. 5, the oil grooves 30 and 31 extend straight in the direction of the velocity vector Vb because the inner peripheral surface of the bearing 20 is developed, but actually the oil grooves 30 and 31 are around the turbine axis. It extends in a spiral with a constant twist angle. When the rotational speed of the turbine shaft 23 fluctuates, the speed vector Vo may be a speed vector at a typical rotational speed. For example, as the speed vector Vo, it is conceivable to use a speed vector at the maximum rotational speed at which the lubrication conditions are most severe, or use a speed vector at the normal rotational speed of the turbine shaft 23.

  Further, a chamfered portion 32 is formed over the entire circumference of the bearing 20 at the boundary between the inner peripheral surface and the end surfaces 20a, 20b of the bearing 20, and oil is passed through the chamfered portion 32 to the end surfaces 20a, 20b. A plurality of vertical grooves 33 communicating with the grooves 30 and 31 are formed. Some of the vertical grooves 33 are provided in alignment with the oil grooves 30 and 31 in the circumferential direction. Then, as shown in an enlarged view in FIG. 6, the rotation of the turbine shaft 23 is caused in each of the end faces 20 a and 20 b of the bearing 20 from the oil grooves 30 and 31 and the longitudinal grooves 33 aligned in the circumferential direction. A tapered portion 34 is formed that extends forward in the direction (the direction indicated by the arrow Vo in FIG. 6) and gradually decreases in depth in the turbine axial direction as it moves away from the longitudinal groove 33 in the rotational direction. Accordingly, the oil guided to the end surfaces 20a and 20b by the oil grooves 30 and 31 passes through these tapered portions 34 and the end surfaces 20a and 20b of the bearing 20 and the rotating body assembly 26 (more specifically, the large-diameter portion 23a of the turbine shaft 23). Or it is led to the gap 35 between the thrust collar 24).

  In the turbocharger 1 configured as described above, the positioning pin 22 extends from the through hole 20c of the bearing 20 to the pin mounting seat surface 17a, and a pipe connection portion 22f is provided at the outer peripheral end of the positioning pin 22. Therefore, the positioning pin 22 can be provided from the outside of the turbocharger housing 1 a to the oil reservoir chamber 27 on the inner peripheral side of the bearing 20 without bringing the oil to be supplied around the bearing 20 into contact with the bearing housing 17. It can be guided through the oil passage 22d. Therefore, the temperature rise of the oil until it reaches the oil reservoir 27 can be suppressed, so that the cooling effect or lubrication effect by the oil inside and outside the bearing 20 can be kept high. Moreover, since a gap is provided between the intermediate portion 22b of the positioning pin 22 and the pin hole 21 of the bearing housing 17, heat transfer from the bearing housing 17 to the positioning pin 22 is suppressed, and oil temperature rise is prevented. The effect is further increased.

  Further, since each of the oil grooves 30, 31 extends from the oil reservoir chamber 27 to both end faces 20a, 20b while being displaced forward in the rotational direction of the turbine shaft 23, the oil grooves 30, 31 are straightened in the turbine axis direction. Compared with the case of providing, the deviation between the direction of the oil velocity vector and the longitudinal direction of the oil grooves 30, 31 during the rotation of the turbine shaft 23 is reduced, whereby the both end surfaces 20 a of the bearing 20 from the oil reservoir chamber 27 are reduced. , 20b can be efficiently supplied, and a sufficient oil film can be reliably formed on the thrust bearing portion between the end faces 20a, 20b and the rotating body assembly 26. Thereby, the cooling effect or lubrication effect of a thrust bearing part can be maintained highly.

  Further, since the tapered portion 34 is provided at the exit portion to both end faces 20a, 20b of the oil grooves 30, 31, oil flowing out from the oil grooves 30, 31 and the end faces 20a, 20b of the bearing 20 and the rotating body assembly 26 are provided. The oil film can be smoothly introduced into the gap between the two and the oil film can be formed more smoothly in the gap. By forming a sufficient oil film on the thrust bearing portion, an increase in the outer diameter of the bearing 20 can be minimized even if the load capacity of the thrust bearing is increased. When the outer diameter of the bearing 20 is increased, it is necessary to increase the outer diameter of the seal ring 40 on the turbine 7 side in order to accommodate the bearing 20 in the bearing hole 18 of the bearing housing 17 from the turbine 7 side. By suppressing the increase in the outer diameter of the bearing 20, an increase in the outer diameter of the seal ring 40 can also be suppressed. Thereby, the increase in the length of the seal ring 40 in the circumferential direction can be suppressed, and the deterioration of the sealing performance can be prevented.

  The present invention is not limited to the above forms, and may be implemented in various forms. For example, the head portion 22a is omitted from the outer peripheral end of the positioning pin, and is substantially flush with the outer peripheral surface (pin mounting seat surface 17a) of the turbocharger housing 1a, in other words, the pin mounting seat of the pin hole 21. An end portion on the outer peripheral side of the positioning pin 22 may be disposed at the opening to the surface 17a, and the oil pipe may be connected to the oil passage 22d at the end portion. In short, it is possible to introduce oil into the oil passage 22d without passing through the pin hole 21 by directly connecting the means for guiding oil from the outside of the housing, such as an oil pipe, to the oil passage 22d. Further, the positioning pin 22 only needs to extend to the opening of the pin hole 21, in other words, to the outer peripheral portion of the supercharger housing 1a. By configuring the positioning pin 22 with a material having a low thermal conductivity, the radial gap between the positioning pin 22 and the pin hole 21 may be narrowed or omitted. The oil introduction portion is not limited to a clear space such as the oil reservoir chambers 27 and 28, but functions as a starting point for introducing the oil guided from the oil passage 22d of the positioning pin 22 into the clearance between the inner and outer circumferences of the bearing 20. As long as it is, it may be formed in various shapes. The bearing structure of the present invention can be applied not only to a turbocharger in which a rotating electrical machine is incorporated, but also to a turbocharger in which no rotating electrical machine exists.

1 is an axial sectional view of a turbocharger according to an embodiment of the present invention. The figure which expands and shows the structure of the bearing vicinity of the turbocharger of FIG. The figure which shows the state which looked at the positioning pin from the arrow III of FIG. The figure which shows the structure of the end surface by the side of the impeller of a bearing. The expanded view of the internal peripheral surface of a bearing. The figure which expands and shows the clearance gap part formed between the end surface of a bearing, and a rotary body assembly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbocharger 1a Supercharger housing 2 Exhaust turbine part 3 Compressor part 4 Rotating electrical machine part 5 Bearing part 17 Bearing housing 17a Pin mounting seat surface 18 Bearing hole 20 Bearing 20a, 20b Bearing end surface 20c Bearing through-hole 20d Bearing Oil hole 21 Pin hole 21a Large diameter portion 21b Small diameter portion 22 Positioning pin 22a Head portion 22b Intermediate portion 22c Tip portion 22d Oil passage 22e Flange 22f Pipe connection portion 23 Turbine shaft 26 Rotating body assembly 27 Oil reservoir chamber Oil introduction part)
28 Oil reservoir (oil introduction part around the bearing)
30, 31 Oil groove 34 Tapered part 42 Bolt (fixing means)

Claims (5)

A housing provided with a bearing hole through which the turbine shaft passes and a pin hole extending from the outer peripheral surface to the bearing hole;
A bearing fitted into the bearing hole;
An oil passage that is fitted in the pin hole so that one end fits into the bearing and the other end reaches the opening on the outer peripheral surface side of the pin hole, and extends in the axial direction from the one end to the other end. And a positioning pin provided with
Oil introduction portions are provided between the inner peripheral surface of the bearing and the turbine shaft and between the outer peripheral surface of the bearing and the bearing hole,
The bearing is provided with an oil hole that penetrates the bearing in a radial direction so as to communicate with the oil introduction portion on the inner and outer periphery of the bearing.
A turbocharger bearing structure characterized by that.   The turbocharger according to claim 1, wherein a gap is provided between an inner peripheral surface of the pin hole of the housing and an outer peripheral surface of the positioning pin fitted in the pin hole. Machine bearing structure.   2. A head portion protruding from the outer peripheral surface of the housing is provided at the other end of the positioning pin, and the head portion is fixed to the outer peripheral surface of the housing using a fixing means. Or the bearing structure of the turbocharger of 2.   Both end surfaces of the bearing are configured as thrust bearings, and the inner peripheral surface of the bearing is gradually displaced forward in the rotational direction of the turbine shaft from the oil introduction portion of the inner periphery of the bearing toward both end sides of the bearing. However, the turbocharger according to any one of claims 1 to 3, wherein a spiral oil groove extending from the oil introduction portion on the inner periphery of the bearing to the both end faces is provided. Machine bearing structure.   Both end faces of the bearing are provided with taper portions in which the depth in the turbine axis direction gradually decreases toward the rotation direction of the turbine shaft relative to the bearing, and the oil groove communicates with the taper portion. The bearing structure of the turbocharger according to claim 4.

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