JP2015127517A - Supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve both the exhaust gas leakage suppression effect and the heat shielding effect by a heat shield plate.SOLUTION: A supercharger is configured so that a bearing housing 2 includes a stepped surface 2d (first contact part) constituted by a wall surface of the bearing housing 2 or a member fixed to the bearing housing 2 and facing part of a turbine housing 4 outward in a radial direction of a shaft, the turbine housing 4 includes an end surface 4d (second contact part) extending outward of the first contact part 2d in the radial direction of the shaft, a flange part 19c (holding part) of a heat shield plate 19 has a bearing housing-side surface that contacts the first contact part 2d, and a turbine housing-side surface that contacts the second contact part 4d, the holding part 19c is held at a position between the first contact part 2d and the second contact part 4d in an axial direction of the shaft, and the holding part 19c contacts the second contact part 4d by a longer range than that of the first contact part 2d, the second contact part 4d extending outward of the first contact part 2d in the radial direction of the shaft.

Description

  The present invention relates to a supercharger including a heat shield that blocks heat from a turbine impeller side to a bearing housing side.

  2. Description of the Related Art Conventionally, a supercharger is known in which a shaft having a turbine impeller provided at one end and a compressor impeller provided at the other end is rotatably supported 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 shaft by the rotation of the turbine impeller. Thus, the supercharger compresses air as the compressor impeller rotates and supercharges the engine.

  As described in Patent Document 1, the turbocharger is provided with an annular heat shield (back plate) between the turbine impeller and the bearing housing, and heat transfer from the turbine impeller to the bearing housing is performed. It can be suppressed. An annular flange portion is formed on the outer peripheral portion of the heat shield plate, and the flange portion is sandwiched between the turbine housing and the bearing housing. Since the flange portion of the heat shield plate is in close contact with the turbine housing and sealed, leakage of exhaust gas from the abutting portion between the turbine housing and the bearing housing to the outside of the turbocharger is suppressed. In addition, a heat insulating space containing gas such as air is formed between the heat shield plate and the bearing housing. The heat insulating space together with the heat shield plate suppresses heat transfer from the turbine impeller to the bearing housing side. ing.

JP 2009-228446 A

  As the heat insulation space is increased, heat transfer from the turbine impeller to the bearing housing is suppressed. However, if the heat insulation space is made large, the radial width of the flange portion becomes small. As a result, the seal length between the flange portion and the turbine housing is shortened, and the effect of suppressing the exhaust gas leakage by the heat shield plate may be diminished depending on the operating conditions of the engine. In other words, if the seal length between the flange portion and the bearing housing is sufficiently secured, the heat insulating space may be reduced, and the heat shielding effect by the heat shielding plate may be reduced.

  The objective of this invention is providing the supercharger which can improve both the suppression effect of the exhaust gas leakage by a heat-shielding board, and a heat-shielding effect.

  In order to solve the above problems, a turbocharger according to the present invention includes a bearing housing that houses a bearing that rotatably supports a shaft, and a turbine housing that houses a turbine impeller provided at one end of the shaft. A supercharger that is fastened to each other and that holds a heat shield holding part that blocks heat from the turbine impeller side to the bearing housing side by a fastening force between the bearing housing and the turbine housing. A wall surface of the bearing housing or a member fixed to the bearing housing is provided, and a first contact portion facing a part of the turbine housing is provided on a radially outer side of the shaft. A second contact portion extending to the outside in the radial direction is provided, and the heat shield plate is provided in the holding portion. The bearing housing side surface is in contact with the first contact portion, the turbine housing side surface of the holding portion is in contact with the second contact portion, and the holding portion is in contact with the first contact portion in the axial direction of the shaft. It is located and hold | maintained between 2nd contact parts, and the holding | maintenance part is contacting to the radial direction outer side of the shaft rather than the 1st contact part with respect to the 2nd contact part.

  The bearing housing may be formed continuously from the radially outer end of the shaft in the first contact portion, and may have a separating portion that is separated from the turbine impeller in the axial direction of the shaft toward the radially outer side of the shaft.

  The separation portion may be a flat surface.

  In the turbine housing, a relief portion that is recessed toward the radially outer side of the shaft may be formed at a portion of the holding portion facing the radially outer end of the shaft.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to improve both the suppression effect of the exhaust gas leak by a heat shield, and a heat shield effect.

It is a schematic sectional drawing of a supercharger. It is an extraction figure of the broken-line part of FIG. It is explanatory drawing for demonstrating a comparative example.

  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.

  FIG. 1 is a schematic cross-sectional view of the supercharger C. In the following description, the direction of arrow L shown in FIG. As shown in FIG. 1, the supercharger C includes a supercharger main body 1. The turbocharger body 1 includes a bearing housing 2, a turbine housing 4 connected to the left side of the bearing housing 2 by a fastening mechanism 3, a seal plate 6 connected to the right side of the bearing housing 2 by a fastening bolt 5, and a seal. A compressor housing 8 connected to the right side of the plate 6 by fastening bolts 7 is integrally formed.

  A protrusion 2 a protruding in the radial direction of the bearing housing 2 is provided on the outer peripheral surface of the bearing housing 2 in the vicinity of the turbine housing 4. Further, a protrusion 4 a that protrudes in the radial direction of the turbine housing 4 is provided on the outer peripheral surface of the turbine housing 4 in the vicinity of the bearing housing 2. The bearing housing 2 and the turbine housing 4 are fixed by fastening the protrusions 2 a and 4 a with the fastening mechanism 3. The fastening mechanism 3 is configured by a G coupling that sandwiches the protrusions 2a and 4a.

  The bearing housing 2 is formed with a bearing hole 2b penetrating in the left-right direction of the supercharger C, and a shaft 12 is rotatably supported by a bearing 10 provided in the bearing hole 2b. A turbine impeller 9 is integrally fixed to the left end (one end) of the shaft 12, and the turbine impeller 9 is rotatably accommodated in the turbine housing 4. A compressor impeller 11 is integrally fixed to the right end portion (the other end) of the shaft 12, and the compressor impeller 11 is rotatably accommodated in the compressor housing 8.

  The compressor housing 8 is formed with an intake port 13 that opens to the right side of the supercharger C and is connected to an air cleaner (not shown). Further, when the seal plate 6 and the compressor housing 8 are connected by the fastening bolt 7, a diffuser flow path 14 that pressurizes air is formed by the facing surfaces of the seal plate 6 and the compressor housing 8. The diffuser channel 14 is formed in an annular shape from the radially inner side to the outer side of the shaft 12, and communicates with the intake port 13 via the compressor impeller 11 on the radially inner side.

  Further, the compressor housing 8 is provided with an annular compressor scroll passage 15 that is located on the radially outer side of the shaft 12 with respect to the diffuser passage 14. The compressor scroll passage 15 communicates with an intake port of an engine (not shown) and also communicates with the diffuser passage 14. Therefore, when the compressor impeller 11 rotates, air is sucked into the compressor housing 8 from the intake port 13 and the sucked air is accelerated by the action of centrifugal force in the process of flowing between the blades of the compressor impeller 11. Then, the pressure is increased by the diffuser flow path 14 and the compressor scroll flow path 15 and led to the intake port of the engine.

  The turbine housing 4 is formed with a discharge port 16 that opens to the left 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 17 and annular turbine scroll flow paths 18 a and 18 b positioned on the radially outer side of the shaft 12 (turbine impeller 9) with respect to the flow path 17. The turbine scroll flow paths 18a and 18b communicate with a gas inlet (not shown) through which exhaust gas discharged from an exhaust manifold of an engine (not shown) is guided, and also communicate with the flow path 17 described above. Therefore, the exhaust gas led from the gas inlet to the turbine scroll passages 18a and 18b is led to the discharge port 16 via the passage 17 and the turbine impeller 9, and the turbine impeller 9 is rotated in the flow process. It becomes.

  Here, the supercharger C has two turbine scroll flow paths 18a and 18b. In the low speed range, exhaust gas is allowed to flow into only one of the two turbine scroll passages 18a and 18b, thereby ensuring a sufficient exhaust gas pressure to rotate the turbine impeller 9.

  Then, the rotational force of the turbine impeller 9 is transmitted to the compressor impeller 11 via the shaft 12, and the air is boosted by the rotational force of the compressor impeller 11 as described above to the intake port of the engine. Will be guided.

  A heat shield plate 19 is disposed in the gap between the turbine impeller 9 and the bearing housing 2. The heat shield plate 19 blocks heat from the turbine impeller 9 side to the bearing housing 2 side.

  FIG. 2 is an extraction diagram of a portion indicated by a broken line A in FIG. As shown in FIG. 2, a fitting hole 4 b into which the bearing housing 2 is fitted is formed on the bearing housing 2 side of the turbine housing 4. The bearing housing 2 and the turbine housing 4 are fastened to each other by the fastening mechanism 3 in a state where the bearing housing 2 is fitted in the fitting hole 4 b of the turbine housing 4.

  In the bearing housing 2, the outer diameter is smaller on the turbine impeller 9 side than the outer peripheral surface 2 c of the portion that fits into the fitting hole 4 b of the turbine housing 4, and the step surface 2 d (first contact portion) is determined from the difference in outer diameter. ) Is formed. The step surface 2 d is a wall surface of the bearing housing 2 and faces the inner peripheral surface of the fitting hole 4 b that is a part of the turbine housing 4 on the radially outer side of the shaft 12.

  Further, in the turbine housing 4, the turbine impeller 9 side of the inner peripheral surface of the fitting hole 4 b is continuous with the inner peripheral surface of the fitting hole 4 b, and the shaft 12 has a shaft more than the inner peripheral surface of the fitting hole 4 b. A projecting portion 4c projecting radially inward is formed.

  Of the protruding portion 4c of the turbine housing 4, the end surface 4d (second contact portion) on the step surface 2d side of the bearing housing 2 and the step surface 2d of the bearing housing 2 are partially located in the radial direction of the shaft 12. overlapping. The end surface 4d extends to the outer side in the radial direction of the shaft 12 than the step surface 2d.

  The heat shield plate 19 is formed in an annular shape and has a facing portion 19 a that faces the turbine impeller 9. On the radially outer side of the facing portion 19a, a cylindrical portion 19b is formed extending in the direction away from the turbine impeller 9 in the axial direction of the shaft 12 from the outer diameter side of the facing portion 19a.

  A heat insulating space H in which a gas such as air is contained is formed by the facing portion 19 a and the cylindrical portion 19 b of the heat shield plate 19 and the bearing housing 2, and the heat insulating space H together with the heat shield plate 19 is a turbine impeller. Heat transfer from 9 to the bearing housing 2 is suppressed.

  And the flange part 19c (holding part) extended toward the radial direction outer side of the shaft 12 from the cylindrical part 19b is provided in the end on the opposite side to the opposing part 19a among the cylindrical parts 19b. The flange portion 19c is positioned between the step surface 2d and the end surface 4d in the axial direction of the shaft 12, and is sandwiched between the step surface 2d of the bearing housing 2 and the end surface 4d of the protruding portion 4c of the turbine housing 4, It is held by the fastening force of the fastening mechanism 3 that fastens the bearing housing 2 and the turbine housing 4. The length in which the radial position of the shaft 12 overlaps the end surface 4d and the stepped surface 2d is the radial length of the surface sandwiching the heat shield plate 19, and the range in which the holding force of the heat shield plate 19 is ensured. Is optional.

  That is, in the heat shield plate 19, the surface on the bearing housing 2 side in the flange portion 19c is in contact with the stepped surface 2d, and the surface on the turbine housing 4 side in the flange portion 19c is in contact with the end surface 4d.

  FIG. 3 is an explanatory diagram for explaining a comparative example. In the comparative example, the heat transfer from the turbine impeller 9 to the bearing housing 2 side is suppressed as the heat insulating space H surrounded by the heat shield plate S and the bearing housing 2 is increased. However, simply trying to secure a large heat insulation space H increases the outer diameter of the cylindrical portion Ro and decreases the radial width of the flange portion F, and the seal length between the flange portion F and the turbine housing 4 is short. turn into.

  On the other hand, the heat insulating space H is likely to be a low pressure portion having a relatively low pressure, and the possibility that the exhaust gas leaks from the fastening mechanism 3 side through the space between the flange portion 19c and the stepped surface 2d is reduced. Therefore, the seal length between the flange portion 19c and the stepped surface 2d is not necessarily the same as the seal length between the flange portion 19c and the end surface 4d, and there may be a difference between the two. Specifically, the seal length between the flange portion 19c and the stepped surface 2d may be shorter than the seal length between the flange portion 19c and the end surface 4d.

  Therefore, in the present embodiment, as shown in FIG. 2, the end surface 4d extends from the step surface 2d to the outside in the radial direction of the shaft 12, and the flange portion 19c is formed from the step surface 2d with respect to the end surface 4d. Is also brought into contact with the radially outer side of the shaft 12.

  The flange portion 19c is pressed against the end surface 4d by the elastic force of the cylindrical portion 19b and the flange portion 19c. Therefore, even if the radial position of the shaft 12 is outside the step surface 2d and there is no pressing force from the step surface 2d side to the flange portion 19c, the sealing performance between the flange portion 19c and the end surface 4d is ensured. Here, in order to increase the elastic force for pressing the flange portion 19c against the end face 4d, the flange portion 19c is formed so as to be inclined toward the turbine housing 4 (protruding portion 4c) toward the radially outer side of the shaft 12. May be.

  Thus, by securing the seal length between the flange portion 19c and the end face 4d, it is possible to improve both the effect of suppressing exhaust gas leakage and the heat shielding effect by the heat shield plate 19 while ensuring a large heat insulating space H. It becomes.

  Further, in the bearing housing 2, a chamfered portion 2 e (separating portion) is formed continuously to the radially outer end of the shaft 12 on the stepped surface 2 d. The chamfered portion 2e is a flat surface that is inclined to the right (in the direction away from the turbine impeller 9 in the axial direction of the shaft 12) in FIG.

  As described above, the bearing housing 2 is fitted into the fitting hole 4 b of the turbine housing 4. At this time, by forming the chamfered portion 2e, the bearing housing 2 and the turbine housing 4 can be easily fitted. However, the length of the stepped surface 2d on the outer side in the radial direction of the shaft 12 is shortened by the amount of the chamfered portion 2e.

  In the present embodiment, the end surface 4d extends to the radially outer side of the shaft 12 than the step surface 2d, and the flange portion 19c is brought into contact with the end surface 4d to the radially outer side of the shaft 12 than the step surface 2d. . Therefore, even if the chamfered portion 2e is formed, it is possible to sufficiently secure the seal length between the flange portion 19c and the end surface 4d. Thus, it is possible to improve both the effect of suppressing the exhaust gas leakage and the heat shielding effect by the heat shield plate 19 while facilitating the fitting of the bearing housing 2 and the turbine housing 4.

  Further, in the turbine housing 4, a relief portion 4 e is formed at a portion where the fitting hole 4 b and the end surface 4 d are continuous. The escape portion 4e is a portion that is recessed toward the radially outer side of the shaft 12, and the flange portion 19c has the radially outer end of the shaft 12 facing the escape portion 4e.

  When the heat shield plate 19 receives heat from the turbine impeller 9 side and becomes high temperature, the heat shield plate 19 extends radially outward due to thermal expansion. Therefore, if the flange part 19c is arranged to the position of the inner peripheral surface of the fitting hole 4b, when the flange part 19c is thermally expanded, the flange part 19c is pressed against the inner peripheral surface of the fitting hole 4b, and the heat shield plate. 19 is deformed.

  By providing the escape portion 4e, a sufficient sealing length between the flange portion 19c and the end surface 4d is secured while avoiding a situation where the flange portion 19c is pressed against the inner peripheral surface of the fitting hole 4b when the flange portion 19c is thermally expanded. It becomes possible.

  In the above-described embodiment, the case where the first contact portion is the step surface 2d that is the wall surface of the bearing housing 2 has been described. However, the first contact portion may be composed of other members fixed to the bearing housing 2 instead of the bearing housing 2.

  In the above-described embodiment, the case where the flange portion 19c of the heat shield plate 19 is sandwiched between the step surface 2d and the end surface 4d has been described. However, although the flange portion 19c of the heat shield plate 19 contacts the step surface and the end surface, it does not have to be sandwiched between the step surface and the end surface.

  In the above-described embodiment, the case where the chamfered portion 2e is formed on the bearing housing 2 has been described. The shape and size are arbitrary, and the chamfered portion 2e may not be formed.

  Further, in the above-described embodiment, the separation portion has been described by taking the chamfered portion 2e configured by a plane as an example. However, the separation portion is not limited to a plane, and the shaft 12 is positioned on the outer side in the radial direction of the shaft 12. If it is separated from the turbine impeller 9 in the direction, it may be R-shaped or curved. Here, when a chamfered shape such as the chamfered portion 2e is formed, since simple machining can be used, workability is good.

  Moreover, although embodiment mentioned above demonstrated the case where the escape part 4e was formed in the turbine housing 4, the escape part 4e is not an essential structure.

  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.

  INDUSTRIAL APPLICABILITY The present invention can be used for a supercharger including a heat shield that blocks heat from a turbine impeller side to a bearing housing side.

C Supercharger 1 Supercharger body 2 Bearing housing 2d Step surface (first contact portion)
2e Chamfered part (separating part)
4 Turbine housing 4d end face (second contact portion)
4e Escape portion 9 Turbine impeller 10 Bearing 12 Shaft 19 Heat shield plate 19c Flange portion (holding portion)

Claims (4)

A bearing housing in which a bearing that rotatably supports a shaft is accommodated and a turbine housing in which a turbine impeller provided at one end of the shaft is accommodated are fastened to each other, and a fastening force between the bearing housing and the turbine housing The supercharger that holds the holding portion of the heat shield that blocks heat from the turbine impeller side to the bearing housing side,
The bearing housing is configured by a wall surface of the bearing housing or a member fixed to the bearing housing, and is provided with a first contact portion facing a part of the turbine housing on a radially outer side of the shaft,
The turbine housing is provided with a second contact portion that extends to a radially outer side of the shaft from the first contact portion,
The heat shield plate has a surface on the bearing housing side of the holding portion in contact with the first contact portion, and a surface on the turbine housing side of the holding portion in contact with the second contact portion, A holding portion is held between the first contact portion and the second contact portion in the axial direction of the shaft;
The supercharger, wherein the holding portion is in contact with the second contact portion to the outside in the radial direction of the shaft with respect to the first contact portion. The bearing housing is
The first contact portion is formed continuously with an end portion on the radially outer side of the shaft, and has a separation portion that is separated from the turbine impeller in the axial direction of the shaft toward the radially outer side of the shaft. The supercharger according to claim 1.   The supercharger according to claim 2, wherein the separation portion is a flat surface.   2. The relief portion that is recessed toward the radially outer side of the shaft is formed in a portion of the turbine housing where the end portion on the radially outer side of the shaft faces the holding portion. 4. The supercharger according to any one of items 1 to 3.

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