JP2018053838A - Exhaust turbo supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust turbo supercharger having excellent supercharging efficiency while making a compressor part compact.SOLUTION: An exhaust supercharger has a compressor housing 5 and an intermediate housing 6, and a shroud 22 having a flange part 22a is fitted and mounted to the compressor housing 5. A compressor chamber 23 and a diffuser part 25 are formed between the shroud 22 and the intermediate housing 6, and a compressor side scroll space 24 is formed between the compressor housing 5 and the shroud 22. The diffuser part 25 has a curl part 25a with an equal groove width, and the curl part 25a is smoothly continued to the compressor side scroll space 24. Since intake air flows smoothly, it can be quickly discharged by effectively using kinetic energy of the intake air.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an exhaust turbocharger provided in an internal combustion engine for automobiles or the like.

  An exhaust turbocharger rotates a compressor by a turbine driven by exhaust gas. The turbine and the compressor are connected by a rotating shaft, and the exhaust gas flows into the turbine from the circumferential direction. While being discharged in the axial direction, the intake air flows into the compressor from the axial direction and is discharged in the circumferential direction (tangential direction).

  The compressor is disposed in the compressor chamber, a compressor side scroll space is formed outside the outer periphery of the compressor chamber, and the compressor chamber and the compressor side scroll space communicate with each other via a ring-shaped diffuser portion. The intake air flows from the diffuser portion into the compressor-side scroll space due to the centrifugal force applied by the compressor, and changes its direction in the circumferential direction in the compressor-side scroll space and is discharged from the outlet.

  The exhaust turbocharger generally includes a turbine housing in which a turbine is disposed, a compressor housing in which a compressor is disposed, and an intermediate housing (bearing housing) positioned between the two, and the compressor housing A compressor chamber and a diffuser portion are formed directly or via another member between the intermediate housing and the intermediate housing.

  Although it is possible to directly form the diffuser part and the compressor chamber with the compressor housing and the intermediate housing, from the viewpoint of accuracy and workability, as disclosed in Patent Document 1, A shroud having a flange portion is mounted, a compressor chamber and a diffuser portion are formed between the shroud and the intermediate housing, and a compressor-side scroll space is often formed between the compressor housing and the shroud. .

  On the other hand, in Patent Document 2, a mounting plate is disposed between the compressor housing and the intermediate housing, and the compressor chamber and the diffuser portion are formed between the compressor housing and the mounting plate. It is formed in the housing.

JP 2014-58884 A JP 2010-303242 A

  As described above, in the compressor, since the intake air flows in the centrifugal direction in the diffuser section and changes the direction in the circumferential direction in the compressor-side scroll space, the direction change of the intake air is performed as smoothly as possible. Need to design. In order to increase the work efficiency of the compressor, the kinetic energy of the intake air should be maintained as much as possible. For this purpose, it is preferable that the diameter of the scroll space on the compressor side is as small as possible. This is also beneficial.

  When Patent Documents 1 and 2 are observed from such a viewpoint, in Patent Document 1, since the diffuser portion is merely a flat disk shape when placed on the plate, the intake air is compressed from the diffuser portion to the compressor. When entering the side scroll space, it is presumed that the intake air tends to collide with the outer peripheral surface of the compressor side scroll space and the smoothness of the intake air flow is hindered.

  In this regard, if the diameter of the compressor-side scroll space is increased, the impact when the intake air collides with the outer periphery of the compressor-side scroll space is reduced, so that the smoothness of the intake flow is improved. As a result, the efficiency is deteriorated and the weight of the exhaust turbocharger is increased.

  On the other hand, in patent document 2, since the terminal part of a diffuser part is curled slightly, it is estimated that the flow of intake air is smooth compared with patent document 1. However, since the degree of curling is slight and the tendency of the intake air to collide with the outer periphery of the compressor-side scroll space remains, it is thought that there is still room for improvement in the smoothing of the intake air flow.

  Further, in Patent Document 2, since the end of the diffuser portion is expanded, the intake air may expand while entering the compressor-side scroll space, and the kinetic energy of the intake air may rapidly decrease. There is a risk that the work efficiency of the compressor may be reduced due to a decrease in strength flowing into the compressor.

  Further, looking at the cross-sectional shape of the compressor-side scroll space, it is presumed that in both Patent Documents 1 and 2, the inner side surface of the intermediate housing is a curved surface that is curved over the entire circumference. However, if the inner surface is curved over the entire circumference, it is presumed that the intake air tends to swirl in the direction perpendicular to the axis of the rotation shaft in the compressor-side scroll space (that is, the swirl flow is reduced). Then, it is estimated that it flows in the circumferential direction of the compressor-side scroll space), and there is a possibility that the intake air moves unnecessarily and the escape performance deteriorates from the compressor-side scroll space, resulting in a decrease in efficiency. Concerned.

  The present invention has been made in view of such a current situation, and aims to provide an improved exhaust turbocharger for the compressor section.

The exhaust turbocharger of the present invention is
A compressor chamber connected to a turbine is rotatably arranged so that intake air flows in the axial direction, a substantially annular compressor-side scroll space formed on the outer periphery of the compressor, and a compressor-side scroll from the compressor chamber It has a ring-shaped diffuser that guides intake air into the space,
The compressor-side scroll space is located on the opposite side of the diffuser portion from the intake air inflow direction, and has a basic configuration in which the outer periphery of the diffuser portion and the outer periphery of the compressor-side scroll space are continuous.

And in the above basic configuration,
A compressor housing, an intermediate housing that overlaps the compressor housing from the turbine side, and a shroud that is fitted to the housing from the intermediate housing side, and the shroud includes a cylindrical portion that fits on an inner periphery of the housing; A flange facing the intermediate housing;
The compressor chamber is formed between the shroud and the intermediate housing, the diffuser portion is formed between the shroud and the intermediate housing, and the compressor side scroll space is formed by a flange of the housing and the shroud. Formed,
The diffuser portion has a curled portion that is curved so as to open in a direction substantially parallel to the outer peripheral surface of the compressor-side scroll space, and the curled portion is set to have an equal groove width.

The present invention includes various configurations. For example, in claim 2,
The compressor-side scroll space has a gradually increasing cross-sectional area from the start end to the end, and the inner surface located on the side of the intermediate housing is entirely curved at the start end and becomes flat from the middle toward the end. The width of the flat surface increases toward the end.

  In the present invention, since the compressor side scroll space is formed by the compressor housing and the shroud, it is easier to form the compressor side scroll space as compared with the case where the compressor side scroll space is formed on the compressor housing as a cast product. The accuracy can also be stabilized. Since the compressor housing and the shroud can use a die-cast product or a resin molded product, it is advantageous in terms of dimensional accuracy and manufacturing cost.

  In the present invention, since at least the outer peripheral portion of the diffuser portion is a curled portion, the flow of intake air is guided by the curled portion, but the curled portion is in a direction substantially parallel to the outer peripheral surface of the compressor-side scroll space. Therefore, the intake air discharged from the curl portion is smoothly guided so as to flow along the outer peripheral surface of the compressor-side scroll space while making the diameter of the compressor-side scroll space as small as possible.

  Therefore, the flow of intake air becomes very smooth when the intake air moves from the diffuser portion to the compressor-side scroll space. As a result, it is possible to facilitate the direction change so that the intake air flows in the circumferential direction in the compressor-side scroll space, contributing to improving the compression efficiency while making the compressor section as compact as possible, and thus improving the fuel efficiency. Can also contribute.

  Moreover, since the diffuser part has the same groove width throughout, it flows into the compressor side scroll space at a high flow velocity, and the kinetic energy can be used for the flow in the circumferential direction in the compressor side scroll space. For this reason, it is possible to increase the supercharging efficiency by making the flow of intake air as fast as possible inside the compressor-side scroll space.

  If the structure of Claim 2 is employ | adopted, since the inner side surface of the compressor side scroll space is a curved surface curved from the start to the middle, while turning inflowed air, flow resistance can be suppressed, On the other hand, it is a flat surface from the middle Therefore, it is possible to greatly suppress the formation of the swirling flow of the intake air in the compressor-side scroll space, and the generated swirling flow disappears on the way. Therefore, the kinetic energy of the intake air can be prevented from being wasted and the intake air can be discharged quickly. Therefore, it can contribute to the improvement of supercharging efficiency.

It is a whole longitudinal front view of an embodiment. It is a separation vertical front view of an embodiment. (A) is a principal part enlarged view, (B) is a principal part enlarged view of (A) further.

(1). Outline Next, an embodiment of the present invention will be described with reference to the drawings. First, an outline of the exhaust turbocharger will be described. In the present embodiment, front / rear / left / right words are used to clarify the direction, and the longitudinal direction of the rotation axis is the left / right direction, and the horizontal direction perpendicular thereto is the front / rear direction. As a precaution, the left-right direction is clearly shown in FIG. 1 (the front-rear direction is a direction orthogonal to the paper surface).

  As shown in FIG. 1, the exhaust turbocharger includes a blade-type turbine 1 and a compressor 2, both of which are integrally fixed by a horizontal rotation shaft 3. The exhaust turbocharger has a turbine housing 4 and a compressor housing 5 and an intermediate housing 6 positioned between the turbine housing 4 and the turbine housing 4. The turbine housing 4 and the intermediate housing 6 are cast as aluminum. It is manufactured integrally. The compressor housing 5 is an aluminum die-cast product or a cast product (a resin molded product can also be used).

  In the turbine housing 4, a turbine chamber 7 in which the turbine 1 is rotatably arranged and a turbine-side scroll space 8 communicating with the outer periphery of the turbine chamber 7 are formed. The turbine-side scroll space 8 has a spiral shape that is larger in cross-sectional area at the start end than the end cross-section and is close to an annular shape, and an exhaust gas introduction passage (not shown) that opens rearward is provided at the start end (upper end). Communicate.

  Although not shown, a flange is formed at the rear end of the inlet cylinder, and this flange is fixed to the cylinder head or the exhaust manifold. In the turbine housing 4, a cylindrical exhaust outlet 9 that exhausts exhaust gas is opened toward the axial center of the rotary shaft 3. A cooling water jacket is formed so as to surround the turbine-side scroll space 8.

  The intermediate housing 6 is formed with a bearing portion 11 into which the rotary shaft 3 is rotatably fitted. A hollow floating metal 12 is disposed on the bearing portion 11 with an oil layer interposed therebetween. An oil inlet 13 penetrating in the vertical direction is formed in the upper part of the bearing part 11, and a hollow oil outlet space 14 is formed in the lower part of the bearing part 11. First and second oil scattering spaces 15 are formed on the left and right sides of the bearing portion 11, and the oil scattering spaces 15 communicate with the oil outlet space 14.

  As shown largely in FIG. 3A, a first oil seal 16 made of metal or the like is fixed to the end of the rotating shaft 3 on the compressor housing 5 side. Note that the cross-sectional display (hatching) of the first oil seal 16 is omitted. The left end portion of the intermediate housing 6 has a large opening. A retainer ring 18 is fixed to the large-diameter opening portion, and a second oil seal 17 is interposed between the retainer ring 18 and the first oil seal 16. ing. The second oil seal 17 is fixed to the first oil seal 16. The end of the rotating shaft 3 is fixed to the compressor 2 with a nut 19.

(2). Compressor portion An intake inlet 21 is opened in the compressor housing 5 in the axial direction, and a cylindrical shroud 22 having a flange portion 22a is inserted into the intake inlet 21 from the intermediate housing 6 side. Thus, the compressor chamber 23 in which the compressor 2 is rotatably arranged is formed by closing the shroud 22 with the intermediate housing 6. The compressor 2 is a well-known type, and has a plurality of blades that are spiral and have a diameter increased toward the intermediate housing 6.

  The compressor housing 5 and the flange portion 22a of the shroud 22 form a substantially annular compressor-side scroll space 24. The compressor chamber 23 and the compressor-side scroll space 24 communicate with each other by a ring-shaped diffuser portion 25. ing. The diffuser portion 25 is formed by the flange portion 22 a of the shroud 22 and the intermediate housing 6. A mating surface between the compressor housing 5 and the shroud 22 is located on the inner circumference of the compressor-side scroll space 24 at a portion having the smallest inner diameter.

  Reference numeral 26 shown in FIGS. 1 and 2 is an intake / discharge port communicating with the end of the compressor-side scroll space 24, and is provided in the compressor housing 5 integrally or separately. Reference numeral 5a indicates a mounting boss for the diaphragm actuator.

  An end of the intermediate housing 6 opposite to the turbine housing 4 is held from the outside by a cylindrical portion formed in the compressor housing 5, and a C-shaped stopper that is elastically deformed to reduce the diameter therebetween. A ring 27 is interposed. By this stopper ring 27, the compressor housing 5 and the intermediate housing 6 are held so as not to be detached.

  The compressor-side scroll space 24 has an enlarged cross-sectional area from the start end to the end, and an intake / discharge port 26 is connected to a passage formed at the enlarged end. The cross-sectional shape of the compressor-side scroll space 24 is narrowed so that the width on the side located on the intermediate housing 6 side is large and the width on the side opposite to the intermediate housing 6 is small. Therefore, the compressor-side scroll space 24 has a copper bowl-shaped cross-sectional shape having a large axial length (height) relative to the radial width, and the outer side surface on the opposite side of the intermediate housing 6. Reference numeral 28 denotes a curved surface curved in an inward concave shape over the entire circumference.

  The inner peripheral surface 29 of the compressor-side scroll space 24 has a flat cross section and is inclined with respect to a line parallel to the axis. The inclination angle θ1 decreases toward the end. The outer peripheral surface 30 is a flat surface over the entire periphery. The outer peripheral surface 30 is slightly inwardly inclined with respect to a line parallel to the axis, but the inclination angle θ2 is substantially the same over the entire circumference. The inner peripheral surface 29 and the outer peripheral surface 30 are smoothly continuous with the outer surface 28 (therefore, the boundary portion is not necessarily clear).

  In the compressor-side scroll space 24, the inner side surface 31 located on the intermediate housing 6 side has a curved surface that is concavely curved inwardly to a certain extent from the start end of the compressor-side scroll space 24, and to some extent from the start end. The inner side surface 31 is smoothly continuous with the inner peripheral surface 29.

  As described above, the diffuser portion 25 is formed between the flange portion 22 a of the shroud 22 and the intermediate housing 6 so as to send the intake air to the compressor-side scroll space 24 by the rotation of the compressor 2. Therefore, the flange portion 22 a of the shroud 22 is a partition wall that separates the compressor-side scroll space 24 and the diffuser portion 25.

  The diffuser portion 25 has a curled portion 25a that is smoothly curved so as to bend toward the compressor-side scroll space 24 by changing the direction from the inner periphery to the outer periphery. In the diffuser portion 25, the groove width e is slightly reduced from the inner peripheral portion to the outer periphery until reaching the curled portion 25a. However, in the curled portion 25a, the groove width e is almost the whole. Are equal. In addition, the curl portion 25a is open toward the direction of the rotation axis of the compressor 2 (the direction opposite to the intermediate housing 6). As a precaution, the opening direction is indicated by an arrow 32 in FIG.

  Since the diffuser portion 25 has a curled portion 25 a, the front end portion of the flange portion 22 a in the shroud 22 is also a curled edge portion 33. The curled edge portion 33 is set so that the thickness decreases toward the tip. Further, the flange portion 22a of the shroud 22 is gradually reduced in thickness from the proximal end toward the distal end. Although not clearly shown in the figure, a slight clearance is provided between the compressor 2, the shroud 22, and the intermediate housing 6.

  In the above configuration, the compressor housing 5 and the shroud 22 can be manufactured by die casting or the like, and can be manufactured with high dimensional accuracy. For this reason, the compressor side scroll space 24 and the diffuser part 25 can also be stabilized with a high dimension. The shroud 22 can also be made of a synthetic resin. In this case, there is an advantage that the weight can be reduced.

  The intake air flowing into the diffuser portion 25 moves in the centrifugal direction and then smoothly changes direction through the curl portion 25a. However, since the curl portion 25a is opened substantially in the axial direction, the compressor side scrolling is performed. It is smoothly guided to the outer peripheral surface 30 of the space 24. Accordingly, the intake air does not collide with the outer peripheral surface 30 to generate turbulent flow, and the intake air flows smoothly into the compressor-side scroll space 24. Therefore, the flow of the intake air in the compressor-side scroll space 24 can be smoothed to contribute to the improvement of the compression efficiency while making the compressor portion as compact as possible, and to the improvement of the fuel consumption.

  The intake air that has flowed into the compressor-side scroll space 24 flows along the inner surface of the compressor-side scroll space 24 as shown by the curved arrows in FIGS. In this case, since the intake air that has flowed into the compressor-side scroll space 24 immediately reaches the inner surface 31 at locations where the cross-sectional area is small, there is a high tendency for swirling flow.

  Therefore, the intake air does not collide with the inner side surface 31 and turbulent flow is generated. Rather, the swirl flow generated in the compressor-side scroll space 24 helps the intake air flow into the compressor-side scroll space 24. So that it works. Accordingly, the inflow of intake air into the compressor-side scroll space 24 and the flow after flowing into the compressor-side scroll space 24 are smooth.

  On the other hand, if the inner side surface 31 of the compressor-side scroll space 24 is a flat surface, the function of the intake air to generate a swirling flow in the compressor-side scroll space 24 is reduced, but the cross-sectional area of the compressor-side scroll space 24 is limited to a certain extent. When it becomes larger, the tendency of the intake air to turn decreases, and the direction is smoothly changed in the circumferential direction. Therefore, intake kinetic energy can be used as a flow in the circumferential direction to quickly eliminate intake air.

  Further, if the inner side surface 31 is formed as a flat surface, the compressor side scroll space 24 can be made compact while the compressor side scroll space 24 can be moved closer to the diffuser portion 25 and the inner peripheral surface 29 can be moved closer to the axial center. Can be That is, the cross-sectional area of the compressor-side scroll space 24 can be gradually increased by reducing the inner diameter without changing the outer diameter of the compressor-side scroll space 24 while ensuring a smooth flow of intake air. Thereby, it can be made compact while enhancing the supercharging efficiency.

  While the embodiments of the present invention have been described above, the present invention can be embodied in various ways. For example, it is possible to form a flat surface on the outer peripheral surface 30 of the compressor-side scroll space 24. Although not mentioned dare, the turbine housing and the intermediate housing may be separate. The range of the curl portion in the diffuser portion can be arbitrarily set as necessary. For example, the whole may be a curled part, or about half of the outer peripheral side may be a curled part.

  The present invention can actually be embodied in an exhaust turbocharger. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Turbine 2 Compressor 3 Rotating shaft 5 Compressor housing 6 Intermediate housing 11 Bearing part 21 Intake inlet 22 Shroud 22a Flange part 23 Compressor chamber 24 Compressor side scroll space 25 Diffuser part 25a Curl part 26 Intake discharge port 28 Outer side surface of compressor side scroll space 29 Compressor-side scroll space inner peripheral surface 30 Compressor-side scroll space outer peripheral surface 31 Compressor-side scroll space inner surface 33 Curled edge

Claims (2)

A compressor chamber connected to a turbine is rotatably arranged so that intake air flows in the axial direction, a substantially annular compressor-side scroll space formed on the outer periphery of the compressor, and a compressor-side scroll from the compressor chamber It has a ring-shaped diffuser that guides intake air into the space,
The compressor-side scroll space is located on the side opposite to the intake air inflow direction from the diffuser portion, and the outer periphery of the diffuser portion and the outer periphery of the compressor-side scroll space are continuous,
A compressor housing, an intermediate housing that overlaps the compressor housing from the turbine side, and a shroud that is fitted to the housing from the intermediate housing side, and the shroud includes a cylindrical portion that fits on an inner periphery of the housing; A flange facing the intermediate housing;
The compressor chamber is formed between the shroud and the intermediate housing, the diffuser portion is formed between the shroud and the intermediate housing, and the compressor side scroll space is formed by a flange of the housing and the shroud. Formed,
And, the diffuser portion has a curled portion that is curved so as to open in a direction substantially parallel to the outer peripheral surface of the compressor-side scroll space, and the curled portion is set to have an equal groove width.
Exhaust turbocharger. The compressor-side scroll space has a gradually increasing cross-sectional area from the start end to the end, and the inner surface located on the side of the intermediate housing is entirely curved at the start end and becomes flat from the middle toward the end. The width of the flat surface is expanding towards the end,
The exhaust turbocharger according to claim 1.

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