JP2010209824A - Scroll part structure and supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll part structure and a supercharger capable of securing a sufficient passage section area and reducing the pressure loss of the fluid. <P>SOLUTION: The structure is for a scroll part 1 of a fluid machine to exchange energy between the fluid G and each rotor blade, the scroll part 1 constituting a flow passage formed spirally around the rotary shaft of the rotor blade, wherein the scroll part 1 has a first transition part 2 with the area decreasing gradually while the section shape makes transition from a corner-rounded square to a circular, in which the radii of curvature C of the corner parts of the first transition part 2 are set to the same size. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a scroll part that forms a flow path formed in a spiral shape around the rotation axis of a moving blade of a fluid machine that exchanges energy between a fluid and a moving blade, and a supercharger including the scroll part structure. In particular, the present invention relates to a scroll structure and a supercharger that can reduce pressure loss.

  One fluid machine that exchanges energy between a fluid and a moving blade is a turbine. A turbine is a fluid machine that obtains power by supplying fluid to blades and converting the kinetic energy of the fluid into rotational motion. One of the apparatuses using such a turbine is a supercharger. For example, a turbocharger for a vehicle includes a gas turbine that rotates a turbine blade by supplying exhaust gas, and a compressor that sucks air by an impeller that is coaxially connected to the turbine blade. I have. The air taken in by the compressor is compressed and supplied to the engine, mixed with fuel and burned. The exhaust gas after combustion is sent to the turbine for work, and finally discharged into the atmosphere. The flow path for supplying the exhaust gas to the turbine rotor blade has a scroll portion formed in a spiral shape around the rotation axis of the turbine rotor blade in order to accelerate the exhaust gas. The exhaust gas is supplied from the direction end face.

  A turbine used for such a turbocharger has a scroll portion as described above, and its cross-sectional shape is generally either a rectangular shape with rounded corners (rounded square shape) or a circular shape. It is. In addition, such a cross-sectional shape is often configured in a similar shape in which the same shape is enlarged or reduced in the circumferential direction (see, for example, Patent Document 1).

JP 2002-206427 A

  However, in a turbine used for a supercharger or the like, the range in which the scroll portion can be formed is limited due to space limitations of the installation location, and such a range that can be formed is given as a frame size in design. Therefore, when the scroll portion is formed in a circular shape, a sufficient cross-sectional area of the flow path cannot be ensured, and the rectangular shape has a problem that corner vortices are generated at the corner portions and pressure loss increases. In addition, when the entire circumferential direction is formed in a rounded quadrangle-like shape, the scroll portion with a small cross-sectional area also has a small R at the corner, and a sufficient flow cross-sectional area cannot be secured. There is a problem that the corner vortex is generated and the pressure loss is increased.

  The present invention has been devised in view of the above-described problems, and provides a scroll structure and a supercharger capable of ensuring a sufficient flow path cross-sectional area and reducing pressure loss of fluid. For the purpose.

  According to the present invention, there is provided a structure of a scroll portion that constitutes a flow path formed in a spiral shape around the rotation axis of the moving blade of a fluid machine that exchanges energy between a fluid and the moving blade, and the scroll portion Has a first transition portion whose area gradually decreases while the cross-sectional shape transitions from a rounded quadrangular shape to a circular shape, and the radius of curvature of the corner portion of the first transition portion is configured to be substantially the same size. A scroll part structure is provided.

  According to the present invention, there is provided a turbocharger comprising: a gas turbine that rotates a turbine blade by supplying exhaust gas; and a compressor that sucks air by an impeller connected coaxially to the turbine blade. The gas turbine has a scroll portion that forms a spiral flow path around the rotation axis of the turbine rotor blade, and the scroll portion has a cross-sectional shape from a rounded quadrangular shape to a circular shape. Provided is a supercharger having a first transition portion whose area gradually decreases while transitioning, and the radius of curvature of the corner portion of the first transition portion is configured to be substantially the same size Is done.

  Moreover, in the scroll part structure and the scroll part of the supercharger described above, the radius of curvature is relative to the radius of the maximum square inscribed circle set within the frame size given as the formable range of the scroll part. The size is 0.1 to 0.9 times, preferably 0.2 to 0.8 times, and more preferably 0.4 to 0.6 times.

  The scroll part may have a second transition part in which the circular shape of the first transition part is gradually reduced in diameter, and the outer edge of the scroll part is an arc part formed with a constant radius. And a gradually decreasing portion having a radius that gradually decreases from the arc portion toward the end point of the scroll portion.

  Further, the fluid machine or the turbine includes a variable nozzle mechanism in which a plurality of rotatable vanes are arranged in an introduction path for supplying fluid from the scroll portion to the moving blade, and a part of the variable nozzle mechanism is You may arrange | position so that it may protrude in a scroll part.

  According to the scroll part structure and the supercharger of the present invention described above, the first transition part is formed, so that a round frame shape is formed in a phase with a large frame size area, and a circular shape is formed in a phase with a small frame size area. In addition, a sufficient flow path cross-sectional area can be ensured in each phase, and the pressure loss of the fluid can be reduced. In particular, by forming the radius of curvature of the corner portion of the first transition portion to the same size, the effect of the present invention can be effectively exerted in a transition section from a rounded quadrangular shape to a circular shape.

  In addition, by setting the radius of curvature of the corner to a predetermined size with respect to the radius of the inscribed circle of the frame size, the hydraulic diameter can be increased and a sufficient flow path cross-sectional area can be ensured. At the same time, the pressure loss of the fluid can be reduced.

  Also, by adding the second transition part, the exit part of the scroll part can be configured smoothly, and by forming the arc part and the gradually decreasing part on the outer edge of the scroll part, a sufficient flow path cross-sectional area is ensured. The pressure loss of the fluid can be reduced.

  Furthermore, the present invention can also be applied to a fluid machine including a variable nozzle mechanism, and even when a part of the variable nozzle mechanism is disposed so as to protrude from the scroll portion, a sufficient flow path is provided. The cross-sectional area can be ensured and the pressure loss of the fluid can be reduced.

It is a figure which shows 1st embodiment which concerns on the scroll part structure of this invention, (A) is the tomogram which laminated | stacked and displayed the cross sections S1-S10 in FIG. 1 (B), (B) is a top view. . 2A is a partial extraction of the tomogram in FIG. 1A, where FIG. 1A is a cross section S1, FIG. 1B is a cross section S3, FIG. 1C is a cross section S5, FIG. 1D is a cross section S6, and FIG. Section S8 is shown. It is a figure which shows 2nd embodiment which concerns on the scroll part structure of this invention, (A) is the tomogram which laminated | stacked and displayed the cross sections S1-S11 in FIG. 3 (B), (B) is a top view. is there. It is a figure which shows 3rd embodiment which concerns on the scroll part structure of this invention, (A) is the tomogram which laminated | stacked and displayed the cross sections S1-S11 in FIG. 4 (B), (B) is a top view. is there. It is a figure which shows the setting range of the curvature radius in 2nd embodiment, and its effect, (A) shows the relationship between a radius ratio and a hydraulic diameter ratio, (B) has shown the relationship between a radius ratio and a pressure loss improvement ratio. . It is sectional drawing of the supercharger which employ | adopted the scroll part structure of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, FIG. 1 is a diagram showing a first embodiment according to the scroll part structure of the present invention, and FIG. 1A is a tomogram in which cross sections S1 to S11 in FIG. ) Is a plan view.

  As shown in FIG. 1A, the scroll part structure of the present invention constitutes a flow path formed in a spiral shape around the rotation axis of a moving blade of a fluid machine that exchanges energy between a fluid G and the moving blade. The scroll portion 1 has a first transition portion 2 whose area gradually decreases while the cross-sectional shape transitions from a rounded quadrangular shape to a circular shape, and a corner portion of the first transition portion 2. The radii of curvature C are substantially the same size. Moreover, the scroll part 1 has the 2nd transition part 3 in which the circular shape of the 1st transition part 2 was diameter-reduced gradually. Note that “substantially the same” includes a case where the radius of curvature C of the corner portion of the first transition portion 2 is intentionally designed to have the same size, and tolerates manufacturing tolerances and errors. It is.

  Further, as shown in FIG. 1B, the scroll portion 1 is formed such that the radius R of the outer edge 11 gradually decreases from the start point P1 toward the end point P3, and the radius r of the inner edge 12 increases from the start point Q1 to the end point. It is formed so as to gradually increase toward P3. That is, the scroll part 1 is formed so that the locus of the center point of the outer edge 11 and the inner edge 12 in the same phase coincides with a circle M passing through the end point P3. The shape of the outer edge 11 and the inner edge 12 of the scroll portion 1 is a shape generally used in a fluid machine such as a turbine. Note that the starting point P1 is a point that coincides with the tangential direction of the outer edge 11 and the flow direction of the fluid G at the inlet of the scroll unit 1, and for convenience of description, the position of the starting point P1 is defined as 0 °. Therefore, although the phase of the end point P3 of the scroll part 1 is set to about 310 degrees here, it is not limited to this numerical value.

  The fluid machine is, for example, a turbine that obtains power by supplying the fluid G to the moving blades. As shown in FIG. 1A, a plurality of fluid machines are provided in the introduction path 4 for supplying fluid from the scroll unit 1 to the moving blades. A variable nozzle mechanism 5 having a rotatable vane 51 is provided, and a protruding portion 52 is formed in which a part of the variable nozzle mechanism 5 protrudes from the scroll portion 1. In addition, the component shown with a dotted line in FIG.1 (B) has shown the turbine disc 6 in which the moving blade of a turbine is standingly arranged.

  By the way, in the turbine used for the supercharger or the like, the formable range of the scroll portion 1 is limited due to the space limitation of the installation location, and such formable range is given as a frame size F in design. Here, FIG. 2 is a partial extraction of the tomogram in FIG. 1A, where FIG. 2A is a section S1, FIG. 2B is a section S3, FIG. 2C is a section S5, and FIG. The cross section S7, (E) shows the cross section S8.

In FIG. 2A, the frame size F is given to a rectangular shape surrounded by a dotted line. Here, if the horizontal width X of the frame size F is x ₁ , the vertical width Y is y ₁ , the radius of curvature C of the corner of the cross section S ₁ is c ₁ , the cross sectional area is A, the circumference is L, and the hydraulic diameter is D. , Cross-sectional area A = (π−4) c ₁ ² + x ₁ y ₁ , circumference L = 2 {(π−4) c ₁ + x ₁ + y ₁ }, hydraulic diameter D = 4 A / L = 2 {(π− 4) c ₁ ² + x ₁ y ₁ } / {(π−4) c ₁ + x ₁ + y ₁ }. Here, since it is assumed that the radial width (horizontal width X) of the scroll portion 1 is restricted, the case where a frame size F of horizontal width X> vertical width Y is given is illustrated. However, when the width (vertical width Y) in the central axis direction of the scroll unit 1 is restricted, a frame size F of vertical width Y> horizontal width X may be given.

The hydraulic diameter means a diameter of a circular tube equivalent to a cross section of a certain flow path, and the cross section S1 can be evaluated as equivalent to a circular cross section flow path having a hydraulic diameter D. Therefore, the larger the hydraulic diameter D, the greater the flow rate that can be sent, and the pressure loss can be reduced. As described above, the hydraulic diameter D is expressed by a function of the curvature radius C and the horizontal width X and vertical width Y of the frame size F, and the frame size F is fixed by an object. That is, the hydraulic diameter D can be adjusted by changing the curvature radius C. Therefore, the radius of curvature C = c ₁ in the cross section S1 is set so that the hydraulic diameter D is as large as possible within the frame size F. A method for setting the curvature radius C will be described later.

And in the scroll part structure of this invention, the shape of each cross section is set according to the frame size F in each cross section, maintaining the curvature radius C = c ₁ set in the cross section S1. That is, as shown in FIG. 2B, the shape of the cross section S3 is set to have a horizontal width X = x ₃ , a vertical width Y = y ₃ , and a curvature radius C = c ₁ . At this time, the cross section S has a relationship of horizontal width X = x ₃ > 2c ₁ and vertical width Y = y ₃ > 2c ₁ and has a rounded quadrangular shape.

Further, as shown in FIG. 2C, the shape of the cross section S5 is set to a horizontal width X = x ₅ , a vertical width Y = y ₅ , and a curvature radius C = c ₁ . At this time, the cross section S has a relationship of a horizontal width X = x ₅ > 2c ₁ and a vertical width Y = y ₅ = 2c ₁ , and a vertical width 2c ₁ and a horizontal width (x ₅ between the semicircular shapes having a radius c _1. -2c ₁ ) (in other words, a capsule shape).

Further, as shown in FIG. 2D, the shape of the cross section S6 is set to a horizontal width X = x ₆ , a vertical width Y = y ₆ , and a curvature radius C = c ₁ . At this time, the cross section S6 has a relationship of horizontal width X = x ₆ = 2c ₁ , vertical width Y = y ₆ = 2c ₁ , and has a circular shape with a radius c ₁ . In the present embodiment, the cross section S1, forms a rounded square shape of the radius of curvature c _1, until sectional S6 that a circular shape of radius c ₁ constitutes a first transition portion 2.

As shown in FIG. 2E, the cross section S8 has a relationship of a horizontal width X = x ₈ = 2c ₈ and a vertical width Y = y ₈ = 2c ₈ , and has a circular shape with a radius c ₈ . . The section S8 constitutes a part of the second transition portion 3 and is gradually reduced in diameter while maintaining a circular shape. In FIG. 2, the radius of curvature C is set based on the cross section S1, but the radius of curvature C may be set based on other cross sections (for example, the cross sections S2 to S6).

  Next, a second embodiment of the scroll part structure according to the present invention will be described. Here, FIG. 3 is a figure which shows 2nd embodiment which concerns on the scroll part structure of this invention, (A) is the tomogram which laminated | stacked and displayed the cross sections S1-S11 in FIG. 3 (B), (B) is a plan view. In addition, the same code | symbol is attached | subjected about the same component as 1st embodiment shown in FIG. 1, and the overlapping description is abbreviate | omitted.

  In the second embodiment shown in FIGS. 3A and 3B, the transition of the cross-sectional shape of the scroll portion 1 has the first transition portion 2 and the second transition portion 3 as in the first embodiment. The shape of the outer edge 11 and the inner edge 12 of the scroll part 1 is improved. That is, the outer edge 11 of the scroll part 1 in the second embodiment includes an arc part 11a having a constant radius R, and a gradually decreasing part 11b in which the radius R gradually decreases from the arc part 11a toward the end point P3 of the scroll part 1. Have.

  Further, the inner edge 12 of the scroll portion 1 is formed such that the radius r gradually increases from the start point Q1 corresponding to the start point P1 of the outer edge 11 toward the end point P3 of the scroll portion 1 as in the first embodiment. Although not shown, the radius r of the inner edge 12 corresponding to the arc portion 11a of the outer edge 11 may be gradually increased, and the radius r of the inner edge 12 corresponding to the gradually decreasing portion 11b of the outer edge 11 may be constant.

  The arc portion 11a is formed from a starting point P1, which is a point that coincides with the tangential direction of the outer edge 11 and the flow direction of the fluid G at the inlet of the scroll portion 1. Here, if the position of the start point P1 is defined as 0 °, the phase of the end point P2 of the arc portion 11a is set to about 250 °, and the phase of the end point P3 of the scroll portion 1 is set to about 310 °. That is, here, the central angle of the arc portion 11a is set to about 250 °. In the second embodiment, the radius R of the outer edge 11 between the start point P1 and the end point P2 is formed to be a constant size.

  The gradually decreasing portion 11b is a curve connecting the end point P2 of the arc portion 11a to the end point P3 of the scroll portion 1, and is formed so that the radius R of the outer edge 11 gradually decreases. The amount of change in the radius R of the gradually decreasing portion 11b changes depending on the phase of the end point P2 of the arc portion 11a. However, when the amount of change increases, the resistance tends to hinder the flow of the fluid G flowing through the scroll portion 1. On the other hand, it is easier to reduce the pressure loss if the arc portion 11a is made longer (the phase of the end point P2 is made larger). Therefore, when adopting the second embodiment, it is necessary to set the phase of the end point P2 of the arc portion 11a in accordance with the type and output of the applied turbine or supercharger. Assuming various turbines and superchargers, and a guideline for setting the phase of the end point P2 of the arc portion 11a is empirically shown, it is preferably 180 ° or more, and preferably 180 ° or more and 270. Or less, preferably 225 ° or more and 270 ° or less.

  According to the scroll part structure of the second embodiment described above, the outer edge 11 and the inner edge 12 are formed so as to be closer to the outer shape of the frame size than the outer edge 11 and the inner edge 12 of the first embodiment. Therefore, in the scroll part 1 of the second embodiment, the fluid G smoothly flows along the arc part 11a of the outer edge 11, and gradually flows toward the end point P3 in the gradually decreasing part 11b. Can be secured.

  Moreover, since the scroll part 1 of 2nd embodiment forms the circular arc part 11a in which the outer edge 11 in flow-path cross-section S1-S8 was formed in constant radius, as shown to FIG. 3 (A), the outer edge 11 Is brought to the upper side of the figure. Similarly, the inner edge 12 is also moved toward the upper side of the drawing. Therefore, the locus L of the center point of the channel cross sections S1 to S11 is a curved line that protrudes upward toward the outer edge 11 as illustrated. Therefore, the inflow angle θ when the fluid G flows from the scroll portion 1 into the introduction path 4 can be reduced, and a portion that becomes a negative pressure is hardly formed on the surface of the protruding portion 52. Moreover, in the scroll part 1 of 2nd embodiment, since the flow path is neared outside, the inner edge 12 has already been set in the substantially same position as the protrusion part 52 in the time of the flow path cross section S5. The protrusion 52 does not obstruct the flow with respect to the fluid G flowing through the cross sections S5 to S11, and pressure loss can be reduced.

  In addition, since the cross sections S7 to S11 of the second transition part 3 are close to the outer edge 11, they are formed in a shape in which a tangent is drawn from a predetermined circular shape toward the introduction path 4, but this This is merely a process for smoothly connecting the cross-sectional shape formed by the invention and the introduction path 4. That is, each cross section S1 to S11 in the second embodiment is set similarly to the first embodiment.

  Next, a third embodiment of the scroll part structure according to the present invention will be described. Here, FIG. 4 is a figure which shows 3rd embodiment which concerns on the scroll part structure of this invention, (A) is the tomogram which laminated | stacked and displayed the cross sections S1-S11 in FIG. 4 (B), (B) is a plan view. In addition, the same code | symbol is attached | subjected about the same component as 1st embodiment shown in FIG. 1, and the overlapping description is abbreviate | omitted.

  In the third embodiment shown in FIGS. 4A and 4B, the scroll part structure of the present invention is applied to the scroll part 1 without the protruding part 52. Therefore, the transition of the cross-sectional shape has the first transition portion 2 and the second transition portion 3 as in the first embodiment. In the third embodiment, the outer edge 11 of the scroll portion 1 is formed such that the radius R gradually decreases from the start point P1 toward the end point P3, and the inner edge 12 of the scroll portion 1 has a radius r from the start point Q1 to the end point P3. Is formed to be constant. Even with such a configuration, it is possible to secure a sufficient flow path cross-sectional area in each phase and reduce the pressure loss of the fluid.

  Here, FIG. 5 is a diagram showing the setting range of the radius of curvature and its effect in the second embodiment described above, (A) is the relationship between the radius ratio and hydraulic diameter ratio, and (B) is the radius ratio and pressure loss. The relationship of the improvement ratio is shown.

  The horizontal axis of FIG. 5A represents the ratio of the radius of curvature C of the corner of the cross-sectional shape to the radius Cs of the inscribed circle of the largest square set within the frame size F given as the formable range of the scroll portion 1. This means that the closer to 1, the closer to a circular shape, and the closer to 0, the closer to a rectangular shape. The vertical axis in FIG. 5A indicates the ratio of the hydraulic diameter D of the cross-sectional shape to the hydraulic diameter Ds of the circular or rectangular cross section.

  As shown in FIG. 5A, when the cross-sectional shape is a rounded square shape, that is, when 0 <radius ratio (C / Cs) <1, the radius ratio (C / Cs) is 0.5. The hydraulic diameter ratio (D / Ds) is maximized. That is, when the radius of curvature C of the corner of the cross-sectional shape is a half value of the radius Cs of the inscribed circle of the largest square set within the frame size F, the hydraulic diameter D is maximized. Therefore, in this case, the hydraulic diameter D can be maximized, a sufficient flow path cross-sectional area can be ensured, and the pressure loss of the fluid can be reduced.

  Further, since the change in hydraulic diameter ratio (D / Ds) is small before and after the radius of curvature C is 0.5 times the radius Cs, the radius of curvature C is 0.4 to 0.6 times larger than the radius Cs. If it is so, the effect of this invention can be exhibited efficiently. Of course, if the hydraulic diameter ratio (D / Ds) is a value greater than 1, the hydraulic diameter D of the cross-sectional shape can be made larger than that of the circular cross section, and the magnitude of the radius of curvature Cs is limited to the above-described numerical value. It is not a thing. For example, if the reference value of the hydraulic diameter ratio (D / Ds) is 1.02, the radius of curvature C may be about 0.1 to about 0.9 times the radius Cs. If the reference value of the diameter ratio (D / Ds) is 1.04, the radius of curvature C may be about 0.2 to about 0.8 times the radius Cs.

  The horizontal axis in FIG. 5B indicates the ratio of the radius of curvature C to the radius Cs, similarly to the horizontal axis in FIG. In addition, the vertical axis of FIG. 5B indicates the pressure loss improvement ratio of a rounded square shape with respect to the cross-sectional shape of a circular cross section or a rectangular cross section.

  As shown in FIG. 5B, when the cross-sectional shape is a rounded square shape, that is, when 0 <radius ratio (C / Cs) <1, the pressure loss is reduced with respect to the cross-sectional shape of the circular cross section or the rectangular cross section. The pressure loss improvement ratio becomes maximum when the radius ratio (C / Cs) is 0.5. That is, when the radius of curvature C of the corner of the cross-sectional shape is half the radius Cs of the inscribed circle of the largest square set in the frame size F, the pressure loss can be reduced most.

  When the radius of curvature C is set to 0.4 to 0.6 times the radius Cs, the pressure loss improvement ratio can be about 0.20 or more, and the radius of curvature C is set to 0 of the radius Cs. When the size is set to 2 to 0.8 times, the pressure loss improvement ratio can be about 0.15 or more, and the radius of curvature C is 0.1 to 0.9 times the radius Cs. It can be seen that the pressure loss improvement ratio can be about 0.10 or more when set to, and the pressure loss can be reduced regardless of the range.

  Finally, a supercharger employing the scroll part structure of the present invention will be described with reference to FIG. Here, FIG. 6 is a cross-sectional view of a supercharger employing the scroll part structure of the present invention. In addition, the same code | symbol is attached | subjected to the same components as the scroll part structure of this invention mentioned above, and the duplicate description is abbreviate | omitted.

  The supercharger of the present invention includes a gas turbine 7 that rotates a turbine blade 61 by supplying exhaust gas, and a compressor 8 that sucks air by an impeller 81 that is coaxially connected to the turbine blade 61. It is a supercharger, and the gas turbine 7 has a scroll part 1 that forms a spiral flow path around the rotation axis of the turbine rotor blade 61, and the scroll part 1 is a first embodiment to a third embodiment. As shown in the embodiment, the cross-sectional shape has the first transition portion 2 whose area gradually decreases while transitioning from a rounded quadrangular shape to a circular shape, and the curvature radius C of the corner portion of the first transition portion 2 is the same. It is structured in size. The turbine rotor blade 61 is erected on the turbine disk 6, and the turbine rotor blade 61 and the turbine disk 6 constitute an impeller of the gas turbine 7.

  The outer shape of the turbocharger supports a turbine housing 71 that constitutes the casing of the gas turbine 7, a compressor housing 82 that constitutes the casing of the compressor 8, and the rotary shaft 9 that connects the turbine disk 6 and the impeller 81. And a center housing 91. The scroll unit 1 constitutes a part of the turbine housing 71. Further, the illustrated supercharger is a so-called supercharger for a vehicle, and in order to obtain an appropriate output of the gas turbine 7 in accordance with the rotational speed of the engine of the vehicle, it is provided between the scroll unit 1 and the turbine rotor blade 61. This is a variable capacity supercharger provided with a variable nozzle mechanism 5 in which a plurality of rotatable vanes 51 are arranged in the introduction path 4.

  Here, the variable nozzle mechanism 5 includes an annular shroud 53 fixed to the turbine housing 71, an annular support ring 54 supported between the turbine housing 71 and the center housing 91, and the shroud 53 and the support ring 54. Are comprised of a plurality of vanes 51 that are rotatably supported, a drive mechanism 55 that rotates the vanes 51, and a pin 56 that maintains a distance between the shroud 53 and the support ring 54. Therefore, a portion surrounded by the shroud 53 and the support ring 54 constitutes the introduction path 4 for supplying the exhaust gas flowing in the scroll portion 1 to the turbine rotor blade 61, and a part of the shroud 53 protrudes to the scroll portion 1. The protrusion part 52 is comprised. Further, the drive mechanism 55 is constituted by a link mechanism, for example, and is powered by an actuator (not shown) arranged outside the supercharger, and can change the angle while synchronizing the plurality of vanes 51. It is configured as follows.

  In the supercharger of the present invention described above, since the scroll part structure of the present invention described above is adopted for the scroll part 1, a sufficient flow path cross-sectional area can be secured in each phase of the scroll part 1, The pressure loss of the fluid can be reduced.

  In addition, the supercharger of this invention is not limited to the thing of the structure shown in figure, The supercharger which does not have the supercharger from which the structure of the variable nozzle mechanism 5 differs, or the variable nozzle mechanism 5 may be sufficient. And it may be a supercharger other than for vehicles, or may have a turbine driven by a gas other than exhaust gas or a liquid such as water.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Scroll part 2 1st transition part 3 2nd transition part 4 Introductory path 5 Variable nozzle mechanism 6 Turbine disk 7 Gas turbine 8 Compressor 9 Rotating shaft 11 Outer edge 11a Arc part 11b Gradually decreasing part 12 Inner edge 51 Vane 52 Projection part 53 Shroud 54 Support Ring 55 Drive mechanism 56 Pin 61 Turbine rotor blade 71 Turbine housing 81 Impeller 82 Compressor housing 91 Center housing

Claims (9)

A structure of a scroll part constituting a flow path formed in a spiral shape around the rotation axis of the moving blade of the fluid machine for exchanging energy between the fluid and the moving blade,
The scroll portion has a first transition portion whose area gradually decreases while the cross-sectional shape transitions from a rounded quadrangular shape to a circular shape, and the radius of curvature of the corner portion of the first transition portion is substantially the same size. It is comprised in the scroll part structure characterized by the above-mentioned.   The curvature radius is 0.1 to 0.9 times larger than the radius of the inscribed circle of the largest square set within the frame size given as the formable range of the scroll part. The scroll part structure according to claim 1.   The radius of curvature is 0.2 to 0.8 times the radius of the inscribed circle of the largest square set within the frame size given as the formable range of the scroll portion. The scroll part structure according to claim 1.   The radius of curvature is 0.4 to 0.6 times the radius of the maximum square inscribed circle set within the frame size given as the formable range of the scroll portion. The scroll part structure according to claim 1.   The scroll part structure according to claim 1, wherein the scroll part has a second transition part in which the circular shape of the first transition part is gradually reduced in diameter.   The outer edge of the scroll part has an arc part formed with a constant radius, and a gradually decreasing part whose radius gradually decreases from the arc part toward the end point of the scroll part. Scroll part structure.   The fluid machine includes a variable nozzle mechanism in which a plurality of rotatable vanes are arranged in an introduction path for supplying fluid from the scroll portion to the moving blade, and a part of the variable nozzle mechanism protrudes from the scroll portion. The scroll part structure according to claim 1, wherein the scroll part structure is arranged as described above.   A turbocharger comprising: a gas turbine that rotates a turbine blade by supplying exhaust gas; and a compressor that sucks air by an impeller connected coaxially to the turbine blade, wherein the gas turbine includes: It has a scroll part which comprises the flow path formed in the spiral shape around the rotating shaft of the said turbine rotor blade, This scroll part is provided with the scroll part structure in any one of Claims 1-6. A turbocharger characterized by that.   The turbine includes a variable nozzle mechanism in which a plurality of rotatable vanes are arranged in an introduction path for supplying fluid from the scroll portion to the rotor blade, and a part of the variable nozzle mechanism protrudes from the scroll portion. The supercharger according to claim 8, wherein