JP5482350B2 - Turbocharger and bearing structure - Google Patents

Description

  The present invention relates to a supercharger that supercharges air supplied to an engine using exhaust energy released from the engine, and a bearing structure of a thrust bearing applied to the supercharger.

  In a typical supercharger, a turbine shaft and a compressor impeller are connected to each other and a rotor shaft that rotates these impellers integrally is supported by a bearing so as to be rotatable with respect to a housing. In addition to radial bearings, thrust bearings are also used as these bearings. For thrust bearings, copper-based materials are often used to improve seizure resistance (see, for example, Patent Document 1 below).

JP-A-1-238716

  For example, if a pair of bearing members attached to the housing side is made of an iron-based material, the rotor shaft side bearings are disposed so as to be opposed to each other between the pair of bearing members and slide relative to the pair of bearing members. It is conceivable to apply a copper-based material to the member.

  However, since copper-based materials are disadvantageous in terms of diversion and cost as compared to iron-based materials, there are aspects that are difficult to apply and improvements are desired.

  Therefore, an object of the present invention is to make it possible to use more iron-based materials advantageous in terms of diversion and cost while ensuring seizure resistance.

The present invention provides a supercharger that supercharges air supplied to the engine by rotating a turbine impeller by exhaust from the engine and rotating a compressor impeller integrally with the turbine impeller via a rotor shaft. The rotor shaft is rotatably supported with respect to the housing by a thrust bearing. The thrust bearing includes a first bearing member provided on one of the rotor shaft and the housing, and the first bearing member. A second bearing member and a third bearing member provided on either one of the rotor shaft and the housing, respectively, located on one side and the other side in the axial direction of the bearing member; While the third bearing member is made of an iron-based material, the first bearing member is a base portion made of an iron-based material, and is provided integrally with the base portion so as to form the second bearing member and the second bearing member. Axially opposite sides in the axial direction in the bearing member, and a sliding portion made of a softer material than the iron-based material, at least one of said third bearing member and the second bearing member is externally An oil passage to which lubricating oil is supplied is provided, and the oil passage is open to the sliding portion made of the soft material .

  According to the present invention, the second bearing member and the third bearing member are made of an iron-based material, while the first bearing member is integrally provided on the base portion made of the iron-based material, and the second and third bearing members. Since both sides in the axial direction opposite to each other are provided with sliding parts made of soft materials, soft materials such as copper-based materials that are disadvantageous in terms of diversion and cost need only at least sliding parts. Therefore, more iron-based materials can be used while ensuring seizure resistance, which is more advantageous in terms of diversion and cost.

It is sectional drawing to which the thrust bearing periphery applied to the supercharger of FIG. 2 was expanded. It is sectional drawing of the supercharger provided with the bearing structure concerning one Embodiment of this invention. (A) is sectional drawing which shows the upper half of the intermediate ring of the thrust bearing in the supercharger of FIG. 2, (b) is sectional drawing of the intermediate ring which shows another example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 2, a turbocharger 1 according to an embodiment of the present invention has a turbine impeller 2 that is rotated by exhaust from, for example, an automobile engine (not shown), and a rotor serving as a rotating shaft with respect to the turbine impeller 2. The compressor impeller 4 rotates integrally with the shaft 3 to supercharge the air supplied to the engine.

  The turbine impeller 2 is rotatably accommodated in a turbine housing 5, and a plurality of turbine blades 7 are provided along the circumferential direction on the outer peripheral side of the turbine wheel 6 at the center. The rotor shaft 3 is integrally connected to the center of the end of the turbine wheel 6 on the compressor impeller 4 side.

  The turbine housing 5 described above has an exhaust intake (not shown) for taking in exhaust from the engine at an appropriate position. The exhaust intake port can be connected to an engine exhaust manifold (not shown). In addition, a turbine scroll passage 8 communicating with the above-described exhaust intake port is formed inside the turbine housing 5 so as to surround the turbine impeller 2. Further, an exhaust outlet 9 for discharging the exhaust gas flowing into the turbine scroll flow path 8 to the outside is formed outside the turbine impeller 2 in the turbine housing 5 in the axial direction (left side in FIG. 2). That is, the turbine scroll flow path 8 and the exhaust discharge port 9 communicate with each other within the turbine housing 5.

  On the other hand, the compressor impeller 4 is rotatably accommodated in the compressor housing 10, and a plurality of compressor blades 12 are provided along the circumferential direction on the outer peripheral side of the compressor wheel 11 at the center.

  An air suction port 13 for sucking air is formed outside the compressor impeller 4 in the compressor housing 10 in the axial direction (right side in FIG. 2). The air suction port 13 is connected to an air cleaner (not shown). Is possible.

  A bearing housing 15 as a housing is provided between the turbine housing 5 and the compressor housing 10. An annular diffuser passage 16 for increasing the pressure of the compressed air is formed on the outer peripheral side (outlet side) of the compressor impeller 4 between the bearing housing 15 and the compressor housing 10. It communicates with the suction port 13.

  Further, a compressor scroll passage 17 is formed inside the outer periphery of the compressor housing 10 so as to surround the compressor impeller 4, and the compressor scroll passage 17 communicates with the diffuser passage 16. That is, the compressor scroll passage 17 and the air inlet 13 are communicated with each other by the diffuser passage 16.

  An air discharge port (not shown) for discharging compressed air is formed at an appropriate position of the compressor housing 10, and this air discharge port communicates with the compressor scroll passage 17, and Can be connected to an intake manifold (not shown).

  A through-hole 11a that penetrates in the extending direction (axial direction) of the rotor shaft 3 is formed at the center of the compressor wheel 11 described above, and the rotor shaft 3 is inserted into the through-hole 11a so as to penetrate the rotor shaft 3. A nut 18 is fastened and fixed to the male screw portion 3a on the end portion protruding outward from the hole 11a.

  Here, the rotor shaft 3 is rotatably supported with respect to the bearing housing 15 by radial bearings 19 provided at two locations in the axial direction of the journal portion 3 b at a position corresponding to the bearing housing 15, and the compressor impeller 4. The thrust bearing 20 is rotatably supported by the thrust bearing 20 in the vicinity. The radial bearing 19 is composed of a float bearing. Either a semi-float type in which a part of the movement of the floating bush (collar) is regulated or a full float type in which the floating bush (collar) is freely rotatable is used. May be used. The thrust bearing 20 will be described later.

  The bearing housing 15 is provided with a lubricating oil passage 21 for supplying lubricating oil to the radial bearing 19 and the thrust bearing 20. The lubricating oil passage 21 includes a radial passage 21a into which lubricating oil is supplied from a lubricating oil supply source (not shown), and an axial passage 21b that communicates with the inner end 21a1 of the radial passage 21a. ing.

  Then, one end 21c1, 21d1 of the radial bearing lubricating oil passages 21c, 21d is connected to the axial passage 21b located on both axial sides of the radial passage 21a, and the radial bearing lubricating oil passages 21c, 21d are connected to each other. The other ends 21c2 and 21d2 extending radially inward are communicated with annular passages 21e and 21f formed in the outer peripheral portion of the radial bearing 19. That is, the lubricating oil flowing into the radial passage 21a from the outside is supplied from the axial passage 21b to the corresponding radial bearings 19 through the radial bearing lubricating passages 21c and 21d and the annular passages 21e and 21f. The radial bearing 19 is lubricated.

  Further, a gap between the rotor shaft 3 and the bearing housing 15 and a later-described gap 31 formed in the bearing housing 15 are communicated with each other at the lower portion of the bearing housing 15 between the two left and right radial bearings 19. A discharge path 15b is formed. Therefore, the lubricating oil after lubricating the radial bearing 19 is also discharged into the gap 31 from the discharge path 15b.

  The end 21b1 of the axial passage 21b on the radial bearing lubricating oil passage 21d side communicates with the side of the thrust bearing 20 described above. That is, a part of the lubricating oil flowing into the radial passage 21a from the outside is supplied to the thrust bearing 20 through the axial passage 21b to lubricate the thrust bearing 20.

  It is assumed that the radial passage 21 a, the axial passage 21 b, and the radial bearing lubricating oil passages 21 c and 21 d of the lubricating oil passage 21 are located in the upper part in the vertical direction with respect to the rotor shaft 3.

  Next, the thrust bearing 20 will be described. In the thrust bearing 20, a turbine side thrust ring 22, an intermediate thrust ring 23, and a compressor side thrust ring 25 are arranged in this order along the axial direction from the turbine impeller 2 side to the compressor impeller 4 side.

  The turbine-side thrust ring 22, the intermediate thrust ring 23, and the compressor-side thrust ring 25 are all bearing members formed in a substantially plate-like ring shape having a through hole into which the rotor shaft 3 is inserted at the center. . That is, the intermediate thrust ring 23 constitutes a first bearing member, and the turbine side thrust ring 22 located on one axial side of the intermediate thrust ring 23 and the compressor side thrust ring 25 located on the other axial side are first A two-bearing member and a third bearing member are configured.

  Here, the rotor shaft 3 includes a small-diameter portion 3c including the male screw portion 3a, which has a small diameter with respect to the journal portion 3b located in the bearing housing 15. That is, the journal portion 3b is a large diameter portion with respect to the small diameter portion 3c, and an abutting surface 3d that is a surface perpendicular to the axial direction of the rotor shaft 3 is formed at the end of the journal portion 3b on the small diameter portion 3c side. It has.

  The intermediate thrust ring 23 is fitted into and fixed to the small diameter portion 3c so that the side surface of the inner peripheral side end portion of the intermediate thrust ring 23 in the thrust bearing 20 is substantially in contact with the abutting surface 3d. That is, the intermediate thrust ring 23 rotates integrally with the rotor shaft 3.

  A generally cylindrical oil draining member 26 is interposed between the intermediate thrust ring 23 and the end surface 11a facing the axial direction on the inner peripheral side of the compressor wheel 11 in the compressor impeller 4. Therefore, by fastening the nut 18 shown in FIG. 2 described above, the compressor impeller 4 allows the intermediate thrust ring 23 and the oil draining member 26 to be brought into contact with the abutting surface 3d of the journal portion 3b in the rotor shaft 3. In the state of being clamped and fixed, the rotor shaft 3 is fastened and fixed.

  The oil draining member 26 includes an annular protrusion 26a that protrudes radially outward on the outer peripheral portion, and suppresses the outflow of the lubricating oil on the thrust bearing 20 side to the compressor impeller 4 side. The inner end of the partition wall 27 separating the compressor impeller 4 and the thrust bearing 20 is substantially in contact with the protrusion 26a of the oil draining member 26 so as to be rotatable. The side end is fixed to the inner wall of the bearing housing 15.

  On the other hand, an annular recess 15a that opens to the compressor impeller 4 side is formed in the bearing housing 15 near the position corresponding to the abutting surface 3d of the journal portion 3b in the rotor shaft 3. And the turbine side thrust ring 22 of the thrust bearing 20 is being fixed to this recessed part 15a.

  At this time, the turbine-side thrust ring 22 has its inner peripheral surface opposed to the outer peripheral surface in the vicinity of the abutting surface 3d of the journal portion 3b so as to be relatively rotatable, and the side surface of the intermediate thrust ring 23 has a side surface. Can be contacted so as to be relatively rotatable. Further, most of the intermediate thrust ring 23 is located in the recess 15a.

  On the other hand, the compressor side thrust ring 25 has its outer peripheral side fixed to the inner wall of the bearing housing 15 as shown in FIG. The compressor side thrust ring 25 is formed with an oil passage 28 through which the end portion 21b1 of the axial passage 21b in the lubricating oil passage 21 is communicated.

  As shown in FIG. 1, the oil passage 28 includes an annular oil passage 28 a that communicates with the end 21 b 1 of the axial passage 21 b and is formed as an annular groove on the surface opposite to the compressor impeller 4. Furthermore, one end communicates with the annular oil passage 28a, one end communicates with the other end of the slanted oil passage 28b, and the other end of the slanted oil passage 28b. And an axial oil passage 28c having the other end opened to the intermediate thrust ring 23 side.

  A plurality of the inclined oil passages 28b and the axial oil passages 28c are provided along the circumferential direction, and the lubricating oil that flows into the annular oil passage 28a from the axial passage 21b is the plurality of the inclined oil passages 28b and the axial oil passages. Via the path 28c, the fine thrust gap between the intermediate thrust ring 23 and the compressor side thrust ring 25 is supplied and lubricated between them.

  In addition, a gap 31 is formed in a lower portion in the vertical direction with respect to the rotor shaft 3 of the bearing housing 15. The gap 31 includes an opening 31 a for discharging the lubricating oil to the outside at the lower end, and the turbine impeller 2. An annular passage 31b is provided in the outer peripheral surface of the journal portion 3b between the radial bearing 19 and the radial passage 19.

  In the turbocharger configured as described above, the exhaust from the engine flows into the turbine scroll passage 8 from the exhaust intake port of the turbine housing 5, whereby the turbine impeller 2 rotates. The compressor impeller 4 rotates. As the compressor impeller 4 rotates, air is sucked from the air suction port 13 of the compressor housing 10 and compressed. The compressed air is discharged from the air discharge port via the diffuser flow path 16 and the compressor scroll flow path 17 to supercharge the air supplied to the engine.

  At this time, the rotor shaft 3 rotates while the radial bearing 19 receives a load in the diameter direction of the rotor shaft 3 while the thrust bearing 20 receives a load in the axial direction of the rotor shaft 3. Here, regarding the thrust bearing 20, when the rotor shaft 3 receives a load toward the turbine side (leftward in FIGS. 1 and 2), the intermediate thrust ring 23 slides against the turbine side thrust ring 22. A sliding bearing is formed by moving and exerts a bearing effect. On the other hand, when the rotor shaft 3 receives a load toward the compressor side (rightward in FIGS. 1 and 2), the intermediate thrust ring 23 is a compressor. By sliding with respect to the side thrust ring 25, a sliding bearing is formed and the bearing effect is exhibited.

  At this time, the lubricating oil flows into the radial passage 21a of the lubricating oil passage 21, and the lubricating oil flows from the radial passage 21a into the axial passage 21b. Part of the lubricating oil flowing into the axial passage 21b is supplied to the outer peripheral portions of the pair of radial bearings 19 via the radial bearing lubricating passages 21c and 21d to lubricate the radial bearings 19. Further, a part of the lubricating oil after lubricating the radial bearing 19 enters a minute gap between the turbine side thrust ring 22 and the intermediate thrust ring 23 on the compressor side, and lubricates between them. Then, it flows out into the annular portion 31 b of the gap 31 of the bearing housing 15.

  The other part of the lubricating oil that has flowed into the axial passage 21b flows into the annular oil passage 28a of the compressor side thrust ring 25 from the end 21b1 of the axial passage 21b, and the inclined oil passage 28b and the axial oil. The oil flows between the intermediate thrust ring 23 and the compressor side thrust ring 25 through the passage 28c, and lubricates between them.

  Then, the lubricated lubricating oil flows out into the gap 31 of the bearing housing 15 and then is discharged to the outside through the opening 31a at the lower end.

  Here, in this embodiment, in the thrust bearing 20, the turbine side thrust ring 22 and the compressor side thrust ring 25 are made of an iron-based material (sintered) such as SCM435H (chromium molybdenum steel), which is an alloy mainly composed of iron. (Including binders).

On the other hand, as shown in an enlarged view in FIG. 3A, the intermediate thrust ring 23 includes an annular base portion 32 and an annular thin plate-shaped sliding portion attached to both side surfaces in the axial direction of the base portion 32 by, for example, pressure bonding. 33, 34. The base 32 is made of an iron-based material such as SCM435H (chromium molybdenum steel), for example, similarly to the turbine-side thrust ring 22 and the compressor-side thrust ring 25, while the sliding portions 33 and 34 are made of iron-based material. Are made of a soft material such as a copper-based material (copper simple metal or copper alloy). As soft materials, there are other, for example, tin.

  The base portion 32 of the intermediate thrust ring 23 includes a fitting hole 32a into which the small diameter portion 3c of the rotor shaft 3 is fitted, and the plate thickness of the sliding portions 33 and 34 is attached to the side surface to which the sliding portions 33 and 34 are attached. The sliding portion receiving recesses 32b and 32c that are slightly shallower are formed in an annular shape. Therefore, in a state where the sliding portions 33 and 34 are dropped and attached to the sliding portion receiving recesses 32b and 32c, the surfaces of the sliding portions 33 and 34 slightly protrude in the axial direction from the side surface of the base portion 32. .

  A sliding bearing is formed between the surfaces of the protruding sliding portions 33 and 34 made of the copper-based material and the turbine side thrust ring 22 and the compressor side thrust ring 25.

  The sliding portions 33 and 34 are not necessarily formed in an annular shape, and a plurality of sliding portions 33 and 34 may be arranged along the circumferential direction.

  As described above, in the present embodiment, the intermediate thrust ring 23 and the copper-based material in which the sliding surfaces of the turbine-side thrust ring 22 and the compressor-side thrust ring 25 located on both sides thereof are provided on the intermediate thrust ring 23. It consists of the sliding parts 33 and 34 which consist of. For this reason, the seizure resistance of the sliding surface can be ensured by the copper-based material.

  On the other hand, the base 32 of the intermediate thrust ring 23 other than the sliding portions 33 and 34, and the entire turbine side thrust ring 22 and compressor side thrust ring 25 are made of an iron-based material. That is, in the present embodiment, more iron-based materials that are advantageous in terms of diversion and cost can be used while ensuring seizure resistance, which is extremely advantageous in terms of diversion and cost, and increases versatility. it can.

  FIG. 3B shows a thrust bearing 20A using an intermediate thrust ring 35 in place of the intermediate thrust ring 23 of FIG. In the intermediate thrust ring 35 of the thrust bearing 20A, a sliding portion 37 made of a cylindrical member is fixed to and integrated with an outer peripheral surface on the outer peripheral side of the annular base portion 36 by, for example, press-fitting. Further, a protective ring 38 as a protective member is fixed and integrated on the outer peripheral side of the sliding portion 37 by press-fitting.

  And the base part 36 and the protection ring 38 are comprised with ferrous materials, such as SCM435H (chromium molybdenum steel), for example like the base part 32 of Fig.3 (a), while the sliding part 37 is shown in Fig.3 (a). Similarly to the sliding portions 33 and 34, a copper-based material (copper simple metal or copper alloy) is used.

  In the state where these three members (the base portion 36, the sliding portion 37, and the protective ring 38) are integrated with each other, the axial side surface of the sliding portion 37 is slightly more axial than the axial side surface of the base portion 36 and the protective ring 38. It shall project in the direction.

  A sliding bearing is formed between the surface of the protruding sliding portion 37 made of the copper-based material and the side surfaces of the turbine side thrust ring 22 and the compressor side thrust ring 25.

  3B, the intermediate thrust ring 35 is provided with sliding surfaces of the intermediate thrust ring 35 and the turbine side thrust ring 22 and the compressor side thrust ring 25 located on both sides thereof. By using the sliding portion 37 made of a copper-based material, seizure resistance can be ensured.

  On the other hand, since the base portion 36 and the protective ring 38 of the intermediate thrust ring 23 other than the sliding portion 37, and the turbine side thrust ring 22 and the compressor side thrust ring 25 are all made of an iron-based material, the diversion surface and cost are reduced. It becomes extremely advantageous in terms of surface and versatility can be improved.

  In particular, in the example shown in FIG. 3A, the sliding parts 33 and 34 made of a copper-based material have a thin plate shape. Therefore, an example in which the sliding part 37 as a cylindrical member in FIG. 3B is used. The amount of the copper-based material to be used can be reduced as compared with the above, and a more remarkable effect can be obtained in terms of diversion and cost.

  On the other hand, in the example of FIG. 3B, by providing the protective ring 38 made of an iron-based material on the outer peripheral side of the sliding portion 37, the sliding portion 37 made of a soft material can be protected. Reliability can be increased.

In the above-described embodiment, in the thrust bearings 20 and 20A, the intermediate thrust rings 23 and 35 are attached to the rotor shaft 3 as the first bearing members, while the turbine side thrust ring 22 and the compressor side thrust ring 25 are the second bearing members. And it is attached to the bearing housing 15 as a third bearing member . In contrast, while attached to the bearing housing 15 of the intermediate thrust ring 23, 35 as a first bearing member, the rotor shaft turbine side thrust ring 22及beauty co compressors thrust ring 25 as a second bearing member and the third bearing member 3 may be attached.

  Further, in the above-described embodiment, the separated thrust bearings 20 and 20A in which the turbine side thrust ring 22 and the compressor side thrust ring 25 located on both sides of the intermediate thrust ring 23 and 35 are separate members are used. The present invention can also be applied to a normal hydrostatic bearing or dynamic pressure bearing in which two members are integrated.

  Further, the present invention may be applied to the journal portion 3b depending on the operating state of the bearing.

2 Turbine impeller 3 Rotor shaft (rotary shaft)
4 Compressor impeller 15 Bearing housing (housing)
20, 20A Thrust bearing 22 Thrust bearing turbine side thrust ring (second bearing member)
23, 35 Thrust bearing intermediate thrust ring (first bearing member)
25 Thrust bearing compressor side thrust ring ( third bearing member)
32, 36 Base part of intermediate thrust ring 33, 34, 37 Sliding part of intermediate thrust ring 38 Protection ring (protective member) of intermediate thrust ring

Claims (5)

A turbine impeller is rotated by exhaust from the engine, and a compressor impeller rotates integrally with the turbine impeller via a rotor shaft, thereby supercharging air supplied to the engine, The rotor shaft is rotatably supported with respect to the housing by a thrust bearing. The thrust bearing includes a first bearing member provided on one of the rotor shaft and the housing, and a shaft of the first bearing member. A second bearing member and a third bearing member, which are respectively located on one side and the other side in the direction and provided on either the rotor shaft or the housing; The first bearing member includes a base portion made of an iron-based material, and the second bearing member and the third bearing member provided integrally with the base portion. Axially opposite sides in the axial direction, and a sliding portion made of a softer material than the iron-based material,
At least one of the second bearing member and the third bearing member has an oil passage to which lubricating oil is supplied from the outside, and the oil passage opens to the sliding portion made of the soft material . A turbocharger characterized by   The supercharger according to claim 1, wherein the sliding portion is a plate-like member attached to both axial sides of the base portion.   The supercharger according to claim 1, wherein the sliding portion is a cylindrical member attached to an outer peripheral side of the base portion.   The supercharger according to claim 3, wherein an annular protective member made of an iron-based material is provided on an outer peripheral side of the sliding portion made of the cylindrical member. A rotating shaft is rotatably supported with respect to the housing by a thrust bearing. The thrust bearing includes a first bearing member provided on one of the rotating shaft and the housing, and an axial direction of the first bearing member. It has a 2nd bearing member and a 3rd bearing member which are located in one side and the other side, respectively, and provided in either one of the rotation axis and the housing, and this 2nd bearing member and 3rd bearing member are On the other hand, the first bearing member is composed of a ferrous material, and a base portion made of a ferrous material and an axial direction provided integrally with the base portion and opposed to the second bearing member and the third bearing member in the axial direction. Both sides comprise a sliding part made of a material softer than the iron-based material ,
At least one of the second bearing member and the third bearing member has an oil passage to which lubricating oil is supplied from the outside, and the oil passage opens to the sliding portion made of the soft material . Bearing structure characterized by.

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