JP2017129052A - Turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the assembling accuracy of an impeller to a rotary shaft.SOLUTION: A thrust collar 12 has an impeller side part 13 having a first wall portion 13a opposed to a first sliding face 11a of a thrust plate 11 at the side of an impeller 3 in the axial direction, a step part side part 14 having a second wall portion 14a opposed to a second sliding face 11b of the thrust plate 11 at the side of a step part 2c in the axial direction, and a cylindrical part 15 extending from the impeller side part 13 to the step part 2c in the axial direction and having a contact end face 15a contacting the step part 2c. The impeller 3, the impeller side part 13 and the cylindrical part 15 are integrally formed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a turbocharger that performs supercharging with exhaust energy from an engine.

  Conventionally, a turbocharger that performs supercharging with exhaust energy from an engine of an automobile or the like is known. In a general turbocharger, a turbine impeller and a compressor impeller are respectively attached to both ends of a rotating shaft. Besides this, a thrust collar, which is a component of a thrust bearing for supporting the rotating shaft in the thrust direction, and the like. The member is also fixed with respect to the rotating shaft. For example, in Patent Document 1, the thrust collar and the impeller (compressor impeller) are tightened together with a nut with respect to the rotating shaft.

JP 2011-1836 A

  Here, the problem of the conventional turbocharger described in Patent Document 1 will be described with reference to FIG. In the conventional turbocharger 101, a stepped portion 102c is formed at the boundary between the small-diameter portion 102a and the large-diameter portion 102b of the rotating shaft 102, and is externally fitted to the small-diameter portion 102a via the thrust collar 112 and the seal collar 122. The nut 121 is fastened to the rotating shaft 102 in a state where the impeller 103 is pressed against the stepped portion 102c. That is, the impeller 103, the thrust collar 111, and the seal collar 122 are fastened together by the nut 121.

  Since the impeller 103 rotates at a high speed of about 200,000 rpm, it is necessary to maintain a high balance during rotation. For this purpose, it is important that the impeller 103 is assembled so as to be perpendicular to the rotation shaft 102. However, since there are separate members such as the thrust collar 112 and the seal collar 122 between the stepped portion 102c of the rotating shaft 102 and the impeller 103, the conventional turbocharger 101 ensures the assembly accuracy of the impeller 103. There was a problem that it was difficult to do.

  The present invention has been made in view of the above problems, and an object of the present invention is to improve the assembly accuracy of the impeller with respect to the rotating shaft.

  The present invention includes a rotary shaft that is rotatably arranged in a housing, has a small diameter portion and a large diameter portion, and has a step portion formed at a boundary between the small diameter portion and the large diameter portion, An impeller attached to the small-diameter portion, a thrust collar disposed between the impeller and the stepped portion in the axial direction of the rotating shaft, and attached to the housing, and rotates the thrust collar from the axial direction. And a thrust bearing having a thrust plate that supports the thrust plate, wherein the thrust collar is opposed to a first sliding surface on the impeller side in the axial direction of the thrust plate. An impeller side portion having a portion, a step portion side portion having a second wall portion facing the second sliding surface on the step portion side in the axial direction of the thrust plate, A cylindrical portion extending in the axial direction from the impeller side portion toward the stepped portion and having a contact end surface that contacts the stepped portion, and the impeller, the impeller side portion, and the cylindrical shape The part is integrally formed.

  In the turbocharger according to the present invention, of the thrust collars arranged between the impeller and the step portion formed on the rotating shaft in the axial direction, the turbocharger faces the first sliding surface on the impeller side in the axial direction of the thrust plate. An impeller side portion having a first wall portion and a cylindrical portion extending in the axial direction from the impeller side portion toward the stepped portion and having a contact end surface that contacts the stepped portion are integrally formed with the impeller. That is, between the impeller and the stepped portion, there are only an impeller side portion and a cylindrical portion integrally formed with the impeller, and there are no other separate members, so that the accuracy of assembling the impeller with respect to the rotating shaft is improved. It becomes possible to make it.

  Further, it is preferable that the step portion side portion is configured by fitting an annular member, which is a separate body from the impeller side portion and the cylindrical portion, to the cylindrical portion.

  Thus, by making the step portion side portion a separate body from other portions, the degree of freedom regarding the material selection of the step portion side portion is improved, and the design of the step portion side portion can be easily optimized.

  In addition, it is preferable that a seal ring for preventing oil supplied to the thrust bearing from moving to the impeller side in the axial direction is provided on the outer peripheral surface of the impeller side portion.

  As shown in FIG. 4, the conventional turbocharger 101 may be provided with a seal ring 118 for suppressing the oil supplied to the thrust bearing 107 from moving to the impeller 103 side. Since the seal collar 122 for holding the seal ring 118 is provided separately from the impeller 103 and the thrust collar 112, the number of members existing between the impeller 103 and the stepped portion 102c increases, so that the impeller 103 This was a factor that reduced assembly accuracy. Therefore, as described above, in the present invention, by providing the seal ring on the outer peripheral surface of the impeller side portion constituting the thrust collar, the seal collar becomes unnecessary, and without reducing the assembly accuracy of the impeller, It is possible to prevent oil from leaking to the impeller side.

  Furthermore, it is more preferable that a plurality of the seal rings are provided between the impeller and the first wall portion in the axial direction.

  In this way, by providing a plurality of seal rings, it is possible to more effectively suppress oil leakage to the impeller side.

  Further, it is preferable that a portion of the first wall portion that is in sliding contact with the first sliding surface of the thrust plate is subjected to wear resistance treatment.

  The material of the impeller may be a relatively soft aluminum material in consideration of workability, while the material of the thrust plate is a high carbon chrome bearing steel material (in consideration of wear resistance, etc.) Steel materials such as SUJ materials are often used. In the present invention, the impeller side portion of the thrust collar is made of the same aluminum material as that of the impeller. Therefore, there is a possibility that the portion where the thrust plate harder than the aluminum material contacts will be worn. Therefore, as described above, the wear of the thrust collar can be suppressed by applying an anti-wear treatment to the portion of the first wall portion that is in sliding contact with the first sliding surface of the thrust plate.

  In addition, it is preferable that at least a part of the impeller side portion and the cylindrical portion and the small diameter portion of the rotating shaft are fixed in an interference fit state.

  In order to firmly fix the impeller to the rotating shaft, it is conceivable to tightly fit the impeller and the rotating shaft. However, when the impeller and the rotating shaft are interference-fitted, a large centrifugal stress is generated in the fastening portion due to the centrifugal force of the impeller with a large outer diameter acting in addition to the initial tensile stress (assembly stress) due to the interference fitting. However, the stress may be excessive. Therefore, as described above, the centrifugal stress generated in the fastening portion can be reduced by tightly fitting the rotary shaft in the impeller side portion and the cylindrical portion of the thrust collar having a smaller outer diameter than the impeller, and the impeller The rotating shaft can be fixed satisfactorily.

It is sectional drawing which shows the structure of the turbocharger which concerns on this embodiment. It is an enlarged view around a thrust collar. It is an enlarged view around a thrust collar in a modification. It is sectional drawing which shows the structure of the turbocharger of a prior art.

  Hereinafter, the turbocharger according to the present embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a configuration of a turbocharger according to the present embodiment, and illustrates a configuration on the compressor side. Since the turbine side configuration is basically a known configuration, a detailed description of the turbine side is omitted.

  A turbocharger 1 shown in FIG. 1 has a basic configuration in which a compressor impeller 3 attached to one shaft end of a rotating shaft 2 and a turbine impeller (not shown) attached to the other shaft end are accommodated in a housing 4. Have. In this embodiment, the compressor impeller 3 corresponds to the “impeller” in the present invention, but the turbine impeller may correspond to the “impeller” in the present invention.

  The rotating shaft 2 is adjacent to the small diameter portion 2a formed at the shaft end, the large diameter portion 2b adjacent to the small diameter portion 2a, and having a larger diameter than the small diameter portion 2a, and the boundary between the small diameter portion 2a and the large diameter portion 2b. And a stepped portion 2c formed. The compressor impeller 3 is attached to the small diameter portion 2 a of the rotating shaft 2.

  The housing 4 includes a bearing housing 5 that houses a thrust bearing 7 that supports the rotating shaft 2 in the thrust direction and a radial bearing 8 that supports the rotating shaft 2 in the radial direction, and a compressor side (left side in FIG. 1) of the bearing housing 5. The compressor housing 6 is provided and accommodates the compressor impeller 3, and the turbine housing (not shown) is provided on the turbine side (right side in FIG. 1) of the bearing housing 5 and accommodates the turbine impeller. The compressor housing 6 is formed with a cylindrical intake passage 9 for supplying intake air from the axial direction of the compressor impeller 3 and a spiral scroll passage 10 for discharging intake air compressed by the compressor impeller 3. Yes.

  In the turbocharger 1 configured as described above, when the turbine impeller is rotated by the energy of exhaust from an engine (not shown), this rotational operation is transmitted to the compressor impeller 3 via the rotating shaft 2, and the compressor impeller 3 is Rotate. Then, intake air is taken into the compressor impeller 3 from the intake passage 9 that is on the axially outer side of the compressor impeller 3, and the intake air is compressed by the rotation of the compressor impeller 3. The intake air compressed by the compressor impeller 3 is discharged into the scroll passage 10 on the radially outer side (centrifugal direction) of the compressor impeller 3.

  Next, the thrust bearing 7 will be described. The thrust bearing 7 includes a thrust plate 11 and a thrust collar 12 and is disposed between the compressor impeller 3 and the stepped portion 2c of the rotating shaft 2 in the axial direction. The thrust plate 11 has an annular shape or a U shape when viewed from the axial direction of the rotary shaft 2, and is fixed to the bearing housing 5 with bolts (not shown). Hereinafter, in the thrust plate 11, the surface on the compressor impeller 3 side in the axial direction is referred to as a first sliding surface 11a (see FIG. 2), and the surface on the stepped portion 2c side in the axial direction is referred to as a second sliding surface 11b. Called.

  FIG. 2 is an enlarged view of the periphery of the thrust collar 12, and shows only the rotating shaft 2, the compressor impeller 3, the thrust plate 11, and the thrust collar 12. The thrust plate 11 is indicated by a one-dot chain line. The thrust collar 12 includes an impeller side portion 13 having a first wall portion 13a facing the first sliding surface 11a of the thrust plate 11, and a second wall portion 14a facing the second sliding surface 11b of the thrust plate 11. And a cylindrical portion 15 having a contact end surface 15a extending in the axial direction from the impeller side portion 13 toward the step portion 2c and contacting the step portion 2c. .

  An annular groove 22 is formed on the outer peripheral surface of the thrust collar 12 by the first wall portion 13 a, the second wall portion 14 a, and the cylindrical portion 15, and the inner edge portion of the thrust plate 11 is engaged with the annular groove 22. It is arranged in the state. With such a configuration, the load in the thrust direction acting on the rotating shaft 2 is caused by the first wall portion 13a being in sliding contact with the first sliding surface 11a of the thrust plate 11, or the second wall portion 14a being thrust plate. By being in sliding contact with the second sliding surface 11 b of 11, the thrust plate 11 is supported.

  The impeller side portion 13 and the cylindrical portion 15 of the thrust collar 12 are integrally formed with the compressor impeller 3. The impeller side portion 13 has a cylindrical shape extending from the back surface of the compressor impeller 3 toward the stepped portion 2c. The cylindrical portion 15 extends further from the impeller side portion 13 to the stepped portion 2 c side, and has a cylindrical shape having a smaller diameter than the impeller side portion 13. The first wall portion 13 a described above is a step portion that forms a boundary between the impeller side portion 13 and the cylindrical portion 15. A through hole 16 is formed along the axial direction of the rotary shaft 2 in the radial direction central portion of the compressor impeller 3 and the impeller side portion 13 and the cylindrical portion 15 of the thrust collar 12. The small diameter part 2a of the rotating shaft 2 is inserted.

  On the other hand, the step portion side portion 14 of the thrust collar 12 is configured by fitting an annular member, which is a separate body from the impeller side portion 13 and the tubular portion 15, to the tubular portion 15. The annular member 14 is externally fitted to the cylindrical portion 15 by, for example, gap fitting.

  When the engine is operated, oil is supplied to the thrust bearing 7 through an oil supply passage (not shown), an oil film is formed between the thrust plate 11 and the thrust collar 12, and the thrust bearing 7 functions as a fluid bearing. At this time, if the oil supplied to the thrust bearing 7 moves to the compressor impeller 3 side, the performance of the compressor impeller 3 may be deteriorated.

  Therefore, in the turbocharger 1 of the present embodiment, a retainer 17 (see FIG. 1) is provided on the radially outer side of the impeller side portion 13 of the thrust collar 12 in order to suppress the oil from moving to the compressor impeller 3 side. Yes. Seal rings 18 and 19 are provided between the outer peripheral surface of the impeller side portion 13 and the opposing surface of the retainer 17 facing the outer peripheral surface. An O-ring 20 is provided between the retainer 17 and the bearing housing 5.

  As shown in FIG. 2, mounting grooves 13 b and 13 c for mounting the seal rings 18 and 19 are formed on the outer peripheral surface of the impeller side portion 13 of the thrust collar 12. Thus, by providing the seal rings 18 and 19 on the impeller side portion 13 of the thrust collar 12, the seal collar 122 provided in the conventional turbocharger 101 shown in FIG. 4 can be omitted.

  Here, the thrust plate 11 of the present embodiment is made of a high carbon chrome bearing steel (SUJ material) excellent in wear resistance. On the other hand, the compressor impeller 3 (including the impeller side portion 13 and the cylindrical portion 15 of the thrust collar 12) is made of an aluminum material having excellent workability. Since the aluminum material is softer than the SUJ material, when the thrust plate 11 supports the rotating shaft 2 in the thrust direction and the thrust plate 11 comes into contact with the first wall portion 13a of the thrust collar 12, the first wall portion 13a is worn. There is a risk.

  In the present embodiment, in order to suppress wear of the first wall portion 13a, wear resistance treatment is applied to at least a portion of the first wall portion 13a that is in sliding contact with the first sliding surface 11a of the thrust plate 11. For example, an alumite treatment can be adopted as the wear resistance treatment, and the wear resistance treatment is preferably performed so that the stepped surface 13a has a hardness equal to or higher than the hardness of the thrust plate 11. The step portion side portion 14 of the thrust collar 12 is separate from the compressor impeller 3, and a material can be selected regardless of the compressor impeller 3. Therefore, if the step portion side portion 14 is made of a material having a hardness equal to or higher than that of the thrust plate 11 (for example, SUJ material), wear of the step portion side portion 14 can be suppressed.

  The turbocharger 1 according to the present embodiment is configured so that the nut 21 is fastened to the rotating shaft 2 while the contact end surface 15a of the cylindrical portion 15 of the thrust collar 12 is in contact with the stepped portion 2c of the rotating shaft 2, thereby The impeller 3 is assembled to the rotating shaft 2. However, in this case, since the compressor impeller 3 and the rotating shaft 2 are fitted in a gap, the compressor impeller 3 may be displaced during rotation. Therefore, in order to firmly fix the compressor impeller 3 with the rotary shaft 2, the compressor impeller 3 may be tightly fitted to the rotary shaft 2 in addition to or instead of the fastening with the nut 21.

  Specifically, the outer diameter of the portion inserted into the area of the thrust collar 12 in the small-diameter portion 2a of the rotary shaft 2 is made slightly larger than the outer diameter of the other portion of the small-diameter portion 2a, or the through hole The compressor impeller 3 and the rotary shaft 2 may be shrink-fitted after the inner diameter of the portion formed in the area of the thrust collar 12 in 16 is slightly smaller than the inner diameter of the other portion of the through hole 16. By doing so, the impeller side portion 13 and the cylindrical portion 15 of the thrust collar 12 and the small diameter portion 2a of the rotating shaft 2 can be fixed in an interference fit state. In addition, you may fix the impeller side part 13 and the cylindrical part 15 of the thrust collar 12, and the small diameter part 2a of the rotating shaft 2 in the interference fitting state by press-fitting instead of shrink fitting.

(effect)
In the turbocharger 1 according to this embodiment, the compressor impeller 3 in the axial direction of the thrust plate 11 among the thrust collars 12 disposed between the compressor impeller 3 and the stepped portion 2c formed in the rotary shaft 2 in the axial direction. An impeller side portion 13 having a first wall portion 13a facing the first sliding surface 11a on the side, and a contact end surface extending in the axial direction from the impeller side portion 13 toward the stepped portion 2c and in contact with the stepped portion 2c A cylindrical portion 15 having 15 a is integrally formed with the compressor impeller 3. That is, between the compressor impeller 3 and the stepped portion 2c, only the impeller side portion 13 and the cylindrical portion 15 that are integrally formed with the compressor impeller 3 are present, and no other separate members are present. It is possible to improve the assembly accuracy of the compressor impeller 3 with respect to the above.

  Further, in the present embodiment, the step portion side portion 14 is configured by externally fitting an annular member, which is a separate body from the impeller side portion 13 and the tubular portion 15, to the tubular portion 15. The degree of freedom regarding the material selection of the side portion 14 is improved, and the design of the stepped portion side portion 14 can be easily optimized.

  In the present embodiment, a seal ring 18 (19) is provided on the outer peripheral surface of the impeller side portion 13 to prevent the oil supplied to the thrust bearing 7 from moving to the compressor impeller 3 side. Thus, by providing the seal ring 18 (19) on the outer peripheral surface of the impeller side portion 13 constituting the thrust collar 12, the seal collar becomes unnecessary, and the assembly accuracy of the compressor impeller 3 is not lowered. The oil can be prevented from leaking to the compressor impeller 3 side.

  Further, in the present embodiment, since a plurality of seal rings 18 and 19 are provided between the compressor impeller 3 and the first wall portion 13a in the axial direction, it is more effective that oil leaks to the impeller side. Can be suppressed. Here, as shown in FIG. 4, in the conventional turbocharger 101, an annular wall 122 a that protrudes radially outward from the outer peripheral surface of the seal collar 122 is provided in order to effectively suppress the oil from moving to the impeller 103 side. It was sometimes provided. However, in the present embodiment, when such an annular wall is provided, the seal ring 18 (19) cannot be attached to the impeller side portion 13 of the thrust collar 12. Therefore, by providing a plurality of seal rings 18 and 19 as described above, it is possible to effectively suppress oil from adhering to the compressor impeller 3 even without an annular wall.

  In the present embodiment, the portion of the first wall portion 13a that is in sliding contact with the first sliding surface 11a of the thrust plate 11 is subjected to wear resistance treatment. Therefore, even if the impeller side portion 13 is made of a material softer than the thrust plate 11, wear of the thrust collar 12 can be suppressed by applying an anti-wear treatment to the portion that is in sliding contact with the thrust plate 11. .

  In the present embodiment, it is preferable that at least a part of the impeller side portion 13 and the cylindrical portion 15 and the small diameter portion 2a of the rotating shaft 2 are fixed in an interference fit state. When the compressor impeller 3 and the rotary shaft 2 are interference-fitted, the centrifugal force of the compressor impeller 3 having a large outer diameter acts on the fastening portion in addition to the initial tensile stress (assembly stress) due to the interference fit. Stress is generated, and the stress may be excessive. Therefore, as described above, the centrifugal stress generated in the fastening portion is reduced by tightly fitting the rotary shaft 2 in the impeller side portion 13 and the cylindrical portion 15 of the thrust collar 12 having an outer diameter smaller than that of the compressor impeller 3. The compressor impeller 3 and the rotating shaft 2 can be fixed well.

[Other Embodiments]
The present invention is not limited to the above embodiment, and the elements of the above embodiment can be appropriately combined or variously modified without departing from the spirit of the present invention.

  For example, in the above embodiment, an annular member is separately provided as the step portion side portion 14 of the thrust collar 12. However, the annular member may be omitted, and the stepped portion 2c of the rotating shaft 2 may function as a stepped portion side portion (second wall portion) of the thrust collar 12, as shown in FIG.

  Moreover, in the said embodiment, the retainer 17 shall be arrange | positioned facing the outer peripheral surface of the impeller side part 13 of the thrust collar 12. FIG. However, it is not essential to provide the retainer 17 so as to face the outer peripheral surface of the impeller side portion 13, and another member (for example, the bearing housing 5) may be arranged so as to face the outer peripheral surface of the impeller side portion 13. It may be. In this case, a seal ring 18 (19) may be provided between the outer peripheral surface of the impeller side portion 13 of the thrust collar 12 and the opposing surface of the other member facing the outer peripheral surface. Note that the number of seal rings is not limited to two, and can be changed as appropriate.

  Moreover, in the said embodiment, the abrasion-resistant process shall be performed with respect to the part which is in sliding contact with the 1st sliding surface 11a of the thrust plate 11 among the 1st wall parts 13a. However, the place where the wear resistance treatment is performed is not limited to this, and the entire first wall portion 13a may be subjected to the wear resistance treatment or may be worn at other places (for example, the cylindrical portion 15). The outer peripheral surface, the side surfaces or the bottom surfaces of the mounting grooves 13b and 13c, etc.) may be subjected to wear resistance treatment.

  In the above embodiment, the annular wall 122a (see FIG. 4) provided in the seal collar 122 of the conventional turbocharger 101 is omitted. However, an annular member corresponding to the annular wall 122a may be retrofitted to the impeller side portion 13 of the thrust collar 12.

1: Turbocharger 2: Rotating shaft 2a: Small diameter portion 2b: Large diameter portion 2c: Stepped portion 3: Compressor impeller (impeller)
7: Thrust bearing 11: Thrust plate 11a: First sliding surface 11b: Second sliding surface 12: Thrust collar 13: Impeller side portion 13a: First wall portion 14: Step portion side portion 14a: Second wall portion 15 : Cylindrical part 15a: contact end face 18, 19: seal ring

Claims (6)

A rotating shaft that is rotatably arranged in the housing, has a small diameter portion and a large diameter portion, and has a stepped portion formed at a boundary between the small diameter portion and the large diameter portion;
An impeller attached to the small-diameter portion of the rotating shaft;
A thrust collar disposed between the impeller and the stepped portion in the axial direction of the rotation shaft, and a thrust plate attached to the housing and rotatably supporting the thrust collar from the axial direction. A thrust bearing having,
A turbocharger comprising:
The thrust collar is
An impeller side portion having a first wall portion facing a first sliding surface on the impeller side in the axial direction of the thrust plate;
A step portion side portion having a second wall portion facing a second sliding surface on the step portion side in the axial direction of the thrust plate;
A cylindrical part extending in the axial direction from the impeller side part toward the step part, and having a contact end surface that contacts the step part;
Have
The turbocharger, wherein the impeller, the impeller side portion, and the cylindrical portion are integrally formed.   2. The turbocharger according to claim 1, wherein the stepped portion side portion is configured by fitting an annular member, which is a separate body from the impeller side portion and the tubular portion, to the tubular portion.   The turbocharger according to claim 1, wherein a seal ring for preventing oil supplied to the thrust bearing from moving toward the impeller in the axial direction is provided on an outer peripheral surface of the impeller side. .   The turbocharger according to claim 3, wherein a plurality of the seal rings are provided between the impeller and the first wall portion in the axial direction.   The turbocharger according to any one of claims 1 to 4, wherein a portion of the first wall portion that is in sliding contact with the first sliding surface of the thrust plate is subjected to wear resistance treatment.   The turbocharger according to any one of claims 1 to 5, wherein at least a part of the impeller side portion and the cylindrical portion and the small diameter portion of the rotating shaft are fixed in an interference fit state.

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