JP2014211094A - Supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercharger capable of inhibiting temperature rise of a bearing housing.SOLUTION: A supercharger 1 includes: a bearing housing 3a which rotatably supports a rotation shaft of a turbine impeller; and a turbine housing 2a where a scroll flow passage 2c for supplying an exhaust gas to the turbine impeller is formed. The bearing housing 3a includes a stepped flange part 10 which faces the turbine housing 2a at multiple steps in an axial direction. The turbine housing 2a includes a stepped recessed part 20 into which the stepped flange part 10 fits, the stepped recessed part 20 facing the bearing housing 3a at multiple steps in the axial direction. The stepped recessed part 20 has nosing parts 22, each of which is cut out at its tip.

Description

  The present invention relates to a supercharger.

  A turbocharger used in an internal combustion engine has a structure in which a compressor impeller and a turbine impeller are coaxially connected. The turbine impeller is rotationally driven by exhaust gas from the internal combustion engine, and the compressor impeller compresses air by the rotational drive. The compressed air is supplied to the internal combustion engine. This supercharger is provided with a cooling structure in order to prevent an increase in the temperature of the bearing housing due to heat transfer from the turbine housing side where the exhaust gas flows and becomes hot.

  As this cooling structure, for example, there are a cooling system using a lubricating oil and a cooling system using cooling water. The cooling method using the lubricating oil forms a lubricating oil flow path communicating with the bearing chamber of the bearing housing, and cools by flowing a large amount of lubricating oil into the bearing chamber. In the cooling method using cooling water, a cooling water channel that does not communicate with the lubricating oil channel is formed in the bearing housing, and cooling is performed by circulating the cooling water through the cooling water channel. As a supercharger including such a lubricating oil flow path and a cooling water flow path, for example, a supercharger described in Patent Document 1 below is known (see FIG. 1 of Patent Document 1).

Japanese Patent Laid-Open No. 5-141259

  By the way, as shown in the above prior art, a heat shield is usually provided between the bearing housing and the turbine housing so as to suppress heat transfer from the turbine housing side. The turbine housing is provided with a recess into which a flange portion formed around the bearing housing is inserted, and the heat shield plate is sandwiched between the flange portion and the recess, and the vicinity thereof is fastened by a bolt. It is fixed with.

  Due to the recent trend toward miniaturization, depending on the model, in order to achieve downsizing in the axial direction, the scroll passage of the turbine housing is arranged closer to the bearing housing side than the conventional model. In such a case, the heat shield plate cannot be arranged as in the conventional case, the heat shield plate itself becomes small, and the area in which the bearing housing and the turbine housing are in direct contact may be widened. If it does so, only the cooling system by the said lubricating oil or cooling water may become inadequate as a cooling structure.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a supercharger that can suppress an increase in temperature of a bearing housing.

In order to solve the above problems, the present invention includes a bearing housing that rotatably supports a rotating shaft of a turbine impeller, and a turbine housing in which a scroll passage that supplies exhaust gas to the turbine impeller is formed. In the turbocharger, the bearing housing has a flange portion with a step which faces the turbine housing in a plurality of steps in the axial direction, and the turbine housing is fitted with the flange portion with the step, A configuration is adopted in which concave portions with stepped portions facing each other in a plurality of steps in the axial direction are provided, and the concave portions with stepped portions have a plurality of stepped nose portions with tips cut out.
By adopting this configuration, in the present invention, the fitting structure between the flange portion of the bearing housing and the concave portion of the turbine housing is formed into a stepped shape, and the tip of the stepped nose portion of the concave portion with the step is cut out and dropped. A gap can be formed at the step corner. Since this gap functions as a space heat insulation part, heat transfer from the turbine housing side that becomes high temperature can be suppressed.

In the present invention, the stepped flange portion employs a configuration in which each of the plurality of nose portions has a curved surface facing the notched tip of the nose portion in a non-contact manner.
By adopting this configuration, in the present invention, a gap functioning as a spatial heat insulating portion can be formed by facing the nose portion and the curved surface with the tip cut away. Further, since there is a curved surface, it is possible to make a structure that avoids stress concentration at the step corners of the stepped flange portion.

Moreover, in this invention, the structure that a part of said scroll flow path is provided to the position in which the said bearing housing is provided in an axial direction is employ | adopted.
By adopting this configuration, in the present invention, by forming a gap in the step corner of the fitting structure of the bearing housing and the turbine housing, heat transfer from the turbine housing side that becomes high temperature can be suppressed. Downsizing in the axial direction of the airframe can be achieved by bringing the scroll flow path of the turbine housing to the position where the bearing housing is provided in the axial direction.

Moreover, in this invention, the structure that the said scroll flow path is a twin scroll flow path is employ | adopted.
By adopting this configuration, in the present invention, the twin scroll flow path of the turbine housing can be moved to the position where the bearing housing is provided in the axial direction, and downsizing in the axial direction of the airframe can be achieved.

Further, in the present invention, a configuration is provided in which a heat shield plate is sandwiched between the bearing housing and the turbine housing on a radially inner side than the opposed surfaces of the stepped flange portion and the stepped recess. Is adopted.
By adopting this configuration, in the present invention, by forming a gap in the step corner of the fitting structure of the bearing housing and the turbine housing, heat transfer from the turbine housing side that becomes high temperature can be suppressed. The heat shield plate can be made smaller than before, and the heat shield plate can be easily clamped and fixed.

Moreover, in this invention, the structure that the cooling water flow path through which cooling water distribute | circulates is formed in the said bearing housing is employ | adopted.
By adopting this configuration, in the present invention, by forming a gap in the step corner of the fitting structure of the bearing housing and the turbine housing, heat transfer from the turbine housing side that becomes high temperature can be suppressed. Even if a cooling system using cooling water is applied as a cooling structure of the bearing housing, the temperature difference in the bearing housing does not increase, and effective cooling with suppressed generation of thermal stress is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the supercharger which can suppress the temperature rise of a bearing housing is obtained.

1 is an overall configuration diagram of a supercharger in an embodiment of the present invention. It is a principal part enlarged view of the supercharger in embodiment of this invention. It is a comparison figure which shows the temperature distribution of the bearing housing in embodiment of this invention. It is a comparison figure which shows the stress distribution of the bearing housing in embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall configuration diagram of a supercharger 1 according to an embodiment of the present invention.
The supercharger 1 receives a turbine 2 that receives exhaust gas exhausted from an internal combustion engine or the like, obtains rotational power, a shaft portion 3 that transmits rotational power obtained by the turbine 2, and a rotation transmitted from the shaft portion 3. And a compressor 4 that compresses air by power.

  The turbine 2 includes a turbine housing 2a and a turbine impeller 2b. The turbine housing 2a is a container that houses the turbine impeller 2b and includes exhaust gas passages (the scroll passage 2c and the exhaust passage 2d) that are connected to the accommodation space of the turbine impeller 2b. The turbine impeller 2b is a radial impeller that is driven to rotate by receiving the exhaust gas flowing from the scroll passage 2c to the exhaust passage 2d.

  The shaft portion 3 includes a bearing housing 3a, a bearing 3b, and a rotating shaft 3c. The bearing housing 3a is a container that accommodates the bearing 3b and the rotating shaft 3c, and is fixed to the turbine housing 2a. The bearing 3b is accommodated in the bearing housing 3a and supports the rotating shaft 3c to be rotatable. The rotary shaft 3 c has one end connected to the turbine impeller 2 b and the other end connected to a compressor impeller 4 b (described later) of the compressor 4.

  The compressor 4 includes a compressor housing 4a and a compressor impeller 4b. The compressor housing 4a is a container that accommodates the compressor impeller 4b and includes an air flow path (intake flow path 4c and scroll flow path 4d) connected to the accommodation space of the compressor impeller 4b. The compressor impeller 4b is a radial impeller that is rotationally driven by the rotational power transmitted through the rotary shaft 3c, compresses the air supplied from the intake passage 4c, and discharges the compressed air to the scroll passage 4d.

  In the supercharger 1 configured as described above, when exhaust gas is introduced from the internal combustion engine into the scroll flow path 2c, the exhaust gas is supplied to the turbine impeller 2b. By supplying the exhaust gas, the turbine impeller 2b, the rotating shaft 3c, and the compressor impeller 4b rotate together. Thereby, rotational power is obtained in the turbine 2, and this rotational power is transmitted to the compressor 4 via the shaft portion 3, and compressed air is generated in the compressor 4.

  Next, the cooling structure of the supercharger 1 will be described.

  As shown in FIG. 1, the bearing housing 3 a is formed with a lubricating oil passage 3 f through which lubricating oil flows and a cooling water passage 3 g through which cooling water flows. The lubricating oil passage 3f is formed inside the bearing housing 3a so as to guide the lubricating oil to the bearing 3b and the rotating shaft 3c. The cooling water channel 3g does not communicate with the lubricating oil channel 3f, and is formed inside the bearing housing 3a so that the cooling water flows around the bearing 3b and the rotating shaft 3c. As described above, the bearing housing 3a includes an oil cooling type and a water cooling type cooling structure.

FIG. 2 is an enlarged view of a main part of the supercharger 1 according to the embodiment of the present invention.
As shown in FIG. 2, a part of the scroll flow path 2c of the turbine housing 2a is provided up to a position where the bearing housing 3a is provided in the axial direction (left and right direction in FIG. 2). The scroll channel 2c is a twin scroll channel whose width in the axial direction increases toward the outer side in the radial direction. Thus, in this embodiment, the scroll flow path 2c of the turbine housing 2a is brought close to the region where the bearing housing 3a is provided in the axial direction.

  A stepped flange portion 10 is provided around the end of the bearing housing 3a on the turbine housing 2a side. The stepped flange portion 10 is provided so as to extend in the radial direction. The stepped flange portion 10 is opposed to the turbine housing 2a in a plurality of stages (two stages in the present embodiment) in the axial direction. The stepped flange portion 10 of the present embodiment includes a facing surface 11a facing the turbine housing 2a on the front side (the left side in FIG. 2 is the front side) and a facing surface 11b facing the turbine housing 2a on the rear side. Have.

  The turbine housing 2a has a stepped recess 20 into which the stepped flange 10 of the bearing housing 3a is inserted. The stepped recess 20 is formed in a shape corresponding to the size and outer shape of the stepped flange 10 so that the stepped flange 10 can be accommodated inside at a predetermined intersection. The stepped recess 20 faces the bearing housing 3a in a plurality of steps (two steps in this embodiment) in the axial direction. The stepped recess 20 of the present embodiment has a facing surface 21a that faces the bearing housing 3a on the front side (the left side in FIG. 2 is the front) and a facing surface 21b that faces the bearing housing 3a on the rear side. .

  The bearing housing 3a is fixed to the turbine housing 2a with bolts 5 on the rear side of the fitting position with respect to the stepped recess 20. The stepped flange portion 10 is accommodated in the stepped concave portion 20 and forms substantially the same plane as the turbine housing 2a. A holding plate 6 is sandwiched between the bolt 5 and the turbine housing 2a. The retainer plate 6 is an annular plate that is inserted into the bolt 5, and is disposed so as to straddle between the stepped flange portion 10 and the turbine housing 2 a.

  A heat shield plate 30 is disposed between the bearing housing 3a and the turbine housing 2a. The heat shield plate 30 is formed in an annular shape and has a bowl-shaped outer peripheral edge portion 31. The outer peripheral edge 31 of the heat shield plate 30 has a bearing housing 3a, a turbine housing 2a, and a turbine housing 2a on the radially inner side of the opposed surfaces (11a, 11b, 21a, 21b) of the stepped flange 10 and the stepped recess 20. It is to be sandwiched between.

The stepped recess 20 has a plurality of nose portions 22 as shown in FIG. The nosing part 22 is a convex corner part of the recessed part 20 with a level | step difference, and two are provided in this embodiment. The tip of the nose 22 is cut away obliquely with respect to the facing surface 21a (21b).
In addition, the stepped flange portion 10 has a plurality of curved surfaces 12 that face the tip of the nose portion 22 in a non-contact manner. The curved surface 12 is a concave corner portion of the stepped flange portion 10, and two curved surfaces 12 are provided corresponding to the nose portion 22. The curved surface 12 is formed so as to be continuously connected to the facing surface 11a (11b).

  Then, the effect | action of the cooling structure of the supercharger 1 comprised as mentioned above is demonstrated.

  In the supercharger 1, for example, an exhaust gas having a temperature of 500 ° C. or higher circulates through the scroll flow path 2c of the turbine housing 2a. For this reason, heat is transmitted from the high-temperature turbine housing 2a side to the bearing housing 3a side. In the supercharger 1 of the present embodiment, as shown in FIG. 2, the bearing housing 3 a has a stepped flange portion 10 that faces the turbine housing 2 a in a plurality of steps in the axial direction, and the turbine housing 2 a A stepped recess 20 into which the stepped flange 10 is inserted is provided.

  Here, the stepped concave portion 20 provided in the turbine housing 2a has a plurality of nose portions 22 whose front ends are notched. The nose portion 22 has a tip notched obliquely with respect to the opposing surface 21 a (21 b), and forms a plurality of gaps S at the stepped corners of the fitting structure of the stepped flange portion 10 and the stepped recess 20. To do. The gap S functions as a space heat insulating portion and suppresses heat transfer from the turbine housing 2a side that becomes high temperature to the bearing housing 3a.

  Further, the stepped flange portion 10 of the bearing housing 3 a has a curved surface 12 that faces the notched tip of the nose portion 22 in a non-contact manner for each of the plurality of nose portions 22. As a result, the nose portion 22 with the tip cut away and the curved surface 12 face each other in a non-contact manner, and a gap S that functions as a space heat insulation portion can be formed. Further, since the curved surface 12 is provided, a structure that avoids stress concentration at the recessed corner portion of the stepped flange portion 10 can be obtained.

FIG. 3 is a comparative view showing a temperature distribution of the bearing housing 3a in the embodiment of the present invention. FIG. 3A shows the temperature distribution of the bearing housing 3a of the present embodiment. FIG. 3B shows a temperature distribution of a bearing housing 3a having a conventional structure (no gap S) as a comparative example. In FIG. 3, the temperature level is represented by the density of the dot pattern.
As shown in FIG. 3B, it can be seen that in the conventional bearing housing 3a, the heat of the turbine housing 2a is transferred to the stepped flange portion 10 and is at a high temperature (indicated by region A). On the other hand, in the bearing housing 3a of this embodiment, as shown to Fig.3 (a), it turns out that the flange part 10 with a level | step difference does not become high temperature.

FIG. 4 is a comparative view showing the stress distribution of the bearing housing 3a in the embodiment of the present invention. FIG. 4A shows the stress distribution of the bearing housing 3a of the present embodiment. FIG. 4B shows a stress distribution of a bearing housing 3a having a conventional structure (no gap S) as a comparative example. In FIG. 4, the level of stress is represented by the shading of the dot pattern.
As shown in FIG. 4 (b), in the bearing housing 3a having a conventional structure, the stepped flange portion 10 is thermally expanded in the radial direction, and is adjacent to the cooling water passage 3g and has a small amount of thermal expansion. It can be seen that large thermal stress (tensile stress) is acting (indicated by region B). On the other hand, in the bearing housing 3a of the present embodiment, since the stepped flange portion 10 does not reach a high temperature, as shown in FIG. 4A, the thermal stress acting on the portion adjacent to the cooling water flow path 3g is reduced. I understand that. Further, it can be seen that the stress concentration is relaxed in the curved surface 12 of the stepped flange portion 10 as compared with the conventional structure.

  Thus, according to this embodiment, the gap S which functions as a space heat insulation part can be formed by facing the nose part 22 and the curved surface 12 with the tip cut off, and the turbine housing becomes a high temperature. Heat transfer from the 2a side to the bearing housing 3a side can be suppressed. Further, according to the present embodiment, even if a cooling method using cooling water is adopted as the cooling structure of the bearing housing 3a, the temperature difference in the bearing housing 3a does not increase as shown in FIG. Effective cooling with suppressed generation of stress is possible.

  Moreover, according to this embodiment, since the clearance S is formed in the stepped corner portion of the fitting structure of the bearing housing 3a and the turbine housing 2a, heat transfer from the turbine housing 2a side that becomes high temperature can be suppressed. As shown in FIG. 2, the range in which the heat shield 30 is provided can be reduced. That is, it is not necessary to extend the heat shield plate 30 to the vicinity of the fastening position by the bolt 5 as in the prior art, the shape of the heat shield plate 30 is reduced in size and simplified, and the processing is facilitated. Can be easily fixed.

  Further, according to the present embodiment, a structure that makes it difficult to extend the heat shield plate 30 to the vicinity of the fastening position by the bolt 5 as in the prior art, that is, as shown in FIG. It is possible to adopt a structure in which 2c is a twin scroll flow path and is moved to a position where the bearing housing 3a is provided in the axial direction. Therefore, according to this embodiment, the downsizing of the supercharger 1 in the axial direction can be achieved.

  Thus, according to the above-described embodiment, the turbine housing in which the bearing housing 3a that rotatably supports the rotating shaft 3c of the turbine impeller 2b and the scroll passage 2c that supplies exhaust gas to the turbine impeller 2b are formed. The bearing housing 3a has a stepped flange portion 10 that faces the turbine housing 2a in a plurality of steps in the axial direction, and the turbine housing 2a has a stepped flange portion 10. By adopting a configuration in which a stepped recess 20 is inserted and is opposed to the bearing housing 3a in a plurality of steps in the axial direction, and the stepped recess 20 has a plurality of stepped noses 22 cut off at the tip. A gap S that functions as a space heat insulating part is formed in the stepped corner of the fitting structure, and a bearing housing It is possible to suppress the temperature rise of the grayed 3a.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above embodiment, the shape in which the tip of the nose portion of the stepped recess is cut obliquely is adopted, but the present invention is not limited to this configuration, and the tip shape of the nose portion is rounded. Or may be cut out so as to dent the tip of the nose.

  In addition, for example, in the above-described embodiment, a configuration in which a curved surface is formed in the concave corner portion of the stepped flange portion facing the nose portion is adopted, but the present invention is not limited to this configuration, and the concave angle of the stepped flange portion is used. Even if the part is a right angle, if the tip of the nose part is notched, a gap that functions as a space heat insulating part can be formed. However, it is preferable to adopt a curved surface in order to avoid stress concentration at the recessed corner portion of the stepped flange portion.

  Further, for example, in the above embodiment, the twin scroll flow path is adopted as the scroll flow path of the turbine housing, but the present invention is not limited to this configuration, and a known single scroll flow path is adopted as the scroll flow path. be able to. Even when a single scroll channel is employed, the present invention can be suitably employed if a structure in which the bearing housing is provided in the axial direction is provided.

  In addition, for example, in the above-described embodiment, a configuration in which the stepped flange portion and the stepped recess have a two-stage structure is adopted, but the present invention is not limited to this configuration, and a three-stage structure is used as long as there are a plurality of stages. A four-step structure or a step structure with more steps can be employed. Further, in this case, it is preferable to cut out the respective tips of the nose portions of the stepped recesses so as to form a gap that functions as a space heat insulation portion according to the number of steps.

  In addition, for example, in the above embodiment, the same cutout shape of the tip of the nose portion of the stepped recess is adopted, but the present invention is not limited to this configuration, and the cutout shape of the tip of the nose portion May be different. For example, on the radially outer side of the stepped flange portion that is likely to be relatively high in temperature, it is preferable to greatly cut out the tip of the nose portion to increase the gap that functions as the space heat insulating portion.

  DESCRIPTION OF SYMBOLS 1 ... Supercharger, 2a ... Turbine housing, 2b ... Turbine impeller, 2c ... Scroll flow path, 3a ... Bearing housing, 3c ... Rotating shaft, 3g ... Cooling water flow path, 10 ... Flange part with level | step difference, 11a, 11b ... Opposite Surface: 12 ... Curved surface, 20: Recessed step, 21a, 21b ... Opposing surface, 22 ... Nose, 30 ... Heat shield

Claims (6)

A turbocharger comprising: a bearing housing that rotatably supports a rotating shaft of a turbine impeller; and a turbine housing in which a scroll passage that supplies exhaust gas to the turbine impeller is formed.
The bearing housing has a stepped flange portion facing the turbine housing in a plurality of steps in the axial direction;
The turbine housing has a stepped concave portion into which the stepped flange portion is fitted and is opposed to the bearing housing in a plurality of steps in the axial direction.
The supercharger according to claim 1, wherein the concave portion with a step has a plurality of nose portions with tips cut out.   2. The supercharger according to claim 1, wherein the flange portion with a step has a curved surface facing the notched tip of the nosing portion in a non-contact manner for each of the plurality of nosing portions.   The supercharger according to claim 1 or 2, wherein a part of the scroll flow path is provided up to a position where the bearing housing is provided in an axial direction.   The supercharger according to claim 3, wherein the scroll channel is a twin scroll channel.   2. A heat shield plate sandwiched between the bearing housing and the turbine housing is provided on a radially inner side with respect to a facing surface between the stepped flange portion and the stepped concave portion. The supercharger as described in any one of 4.   The supercharger according to any one of claims 1 to 5, wherein a cooling water flow path through which cooling water flows is formed in the bearing housing.