JP2008163760A - Radial impeller and supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the stiffness of a radial impeller while minimizing increase of the weight of the radial impeller. <P>SOLUTION: The radial impeller has a plurality of blades w erected on a side of a disc d, wherein the disc d is formed to be thick near the roots of the blades w and thin in the other area. The side of the disc d where the blades w are erected is raised so that the disc d is shaped to be thick near the blade roots. A back side of the disc d where the blades w are erected is raised so that the disc d is shaped to be thick near the blade roots. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radial impeller and a supercharger.

  Radial impellers are used as turbocharger turbine impellers and compressor impellers. The turbocharger rotates the turbine impeller by the exhaust gas of the internal combustion engine and rotates a rotating shaft connected to the turbine impeller, and the compressor impeller is rotated by the rotation driving of the rotating shaft to compress the gas to a high pressure. By supplying the formed gas to the internal combustion engine, the output and efficiency of the internal combustion engine are improved.

As shown in Fig. 4, in the radial impeller, the blades are pulled in the outer circumferential direction due to the centrifugal force during high-speed rotation, so high stress is generated on the disc (especially the blade root near the joint between the blade and the disc). To do. In order to withstand this high stress, it is necessary to design the shape so that the disk has a predetermined strength.
In this case, conventionally, as shown in the schematic cross-sectional view of FIG. 3A, the disk d is uniformly thickened on one side, or as disclosed in Patent Document 1 below, an impeller is provided on the back side of the disk. A circular rib concentric with the shaft center is formed, and as disclosed in Patent Document 2, the outer peripheral portion of the disk is formed thicker than the inner peripheral portion.
JP 2005-155446 A JP 2001-304181 A

According to the conventional method described above, the effect of improving the strength of the radial impeller can be obtained, but on the other hand, there is a disadvantage that the moment of inertia increases due to the increase in weight and the response to rotation deteriorates.
Further, when the material of such a radial impeller is a casting, the weight balance may be slightly asymmetric with respect to the shaft center, the weight unbalance becomes large, and the rotation becomes unstable. Further, when the weight at a position far from the axial center of the radial impeller is increased as in Patent Document 2, the rotation becomes more unstable.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to improve the strength of a radial impeller while minimizing an increase in the weight of the radial impeller. Moreover, it aims at proposing the supercharger provided with such a radial impeller.

In order to solve the above problems, in the present invention, as a first means, a radial impeller in which a plurality of blades are erected on one surface of a disk, the thickness of the disk being thick in the vicinity of the blade root. A radial impeller characterized by being thinly molded in the above area was adopted.
Here, the thickness of the disk is a distance from a predetermined position of the disk surface on which the blades are attached to the disk to the disk back surface extending in a direction parallel to the rotational axis of the radial impeller.

  Further, as a second means, in the radial impeller according to the first means, the disk is formed thick in the vicinity of the blade root by raising the surface of the disk on which the blade is erected. Adopted what is.

  As a third means, in the radial impeller according to the first means, the thickness of the disk is increased in the vicinity of the blade root by raising the back surface of the surface of the disk on which the blade is erected. Adopted what is.

  As a fourth means, in the radial impeller according to the first or second means, the base of the adjacent blades is formed into a shape connected by a curve formed by a combination of a plurality of arcs, so that the thickness of the disk is A material that is thick in the vicinity of the blade root and thin in other areas was adopted.

  As a fifth means, in the radial impeller according to the first or second means described above, the thickness of the disk is set so that the roots of the adjacent blades are connected by a curve having a plurality of inflection points. A material that is thick in the vicinity of the blade root and thin in other areas was adopted.

  As a sixth means, in the radial impeller according to any one of the first or third means, an unevenness having a radial ridge line is formed on the back surface of the surface on which the blades of the disk are erected. The disc was thick in the vicinity of the blade root and thin in other areas.

  As a seventh means, in the radial impeller according to the sixth means, the contour of the unevenness is a combination of a plurality of arcs.

  Furthermore, in the present invention, as an eighth means, the outside air sucked by the compressor impeller connected to the turbine impeller and rotated in accordance with the rotational drive of the turbine impeller is compressed by the exhaust gas from the internal combustion engine. A turbocharger that discharges in the above-described manner is employed, wherein the turbine impeller and / or the compressor impeller is the radial impeller according to any one of claims 1 to 7.

  According to the present invention, the thickness of the disk is increased in the vicinity of the base of the blade of the disk included in the radial impeller, that is, in the high stress generation region, so that the strength of the high stress generation region of the disk can be increased and the generated stress is reduced. be able to. Furthermore, since the disk thickness between the blades with low generated stress can be reduced to such an extent that a predetermined strength can be obtained, an increase in the weight of the radial impeller can be suppressed. In this case, when the radial impeller is a turbine impeller, the loss due to the collision with the exhaust gas at the edge of the disk is reduced by thinning the outer periphery of the disk, so that the efficiency can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a supercharger 10 in the present embodiment. The supercharger 10 includes a turbine impeller 11, a compressor impeller 12, a shaft 13, a housing 14, a bearing 15, a nozzle portion 16, and the like.

FIG. 2 is a perspective view showing an appearance of the turbine impeller 11.
The turbine impeller 11 and the compressor impeller 12 are radial impellers in which a plurality of blades w are erected on one surface of the disk d. The turbine impeller 11 rotates by receiving torque from the exhaust gas G that flows in from the outer peripheral portion thereof, flows between adjacent blades w, and escapes in the axial direction. The compressor impeller 12 is rotationally driven to compress the outside air flowing in from the axial direction to the side where the blades w of the disk d are erected.

  FIG. 3 is a development view showing a part of the state in which the disk d and the blades w of the turbine impeller 11 are viewed from the outer peripheral side of the turbine impeller 11. The thickness of the disk d of the turbine impeller 11 of the present embodiment is increased in the vicinity of the root of the blade w, and is reduced to such an extent that a predetermined rigidity is satisfied in other regions. As a method of changing the thickness depending on the positional relationship with the blade w of the disk d, for example, there are those shown in FIGS.

  FIG. 3A shows a conventional disk d 'shown for comparison. FIG. 4 is a diagram showing the stress applied to the disk d 'of the conventional turbine impeller 11'. As shown in this figure, in the conventional disk d ', high stress tends to be generated near the root of the blade w. The conventional disk d 'is uniformly thickened on one side in order to withstand high stress near the root of the blade w'. Here, the arcs R11 and R12 at the roots of the blades w 'are referred to as fillet ares, and are necessary to alleviate local stress concentration at the blade roots of the turbine impeller 11'.

  FIG. 3 (b) is a raised side of the disk d that serves as a flow path for the exhaust gas G, that is, the surface on which the blades w are erected, and the roots of the blades w are formed from three arcs R21 to R23. Are connected by a curved line. Here, the arcs R21 and R22 are arcs having a diameter larger than that of the arc normally provided as a fillet are, and are smoothly connected by the arc R23.

  FIG. 3 (c) shows a side where the exhaust gas G of the disk d does not flow, that is, the back of the surface on which the blades w are erected, and the position corresponding to the root of each blade w is indicated by an arc R31. Is raised, and the space between adjacent blades w is recessed by an arc R32. The arcs R33 and R34 at the roots of the blades w are called fillet rounds, and are necessary to alleviate local stress concentration at the blade roots of the turbine impeller 11.

  FIG. 3 (d) shows an increase in the vicinity of the roots of the blades w on both sides of the disk d, and the roots of the blades w are formed from three arcs R41 to R43 on the surface where the blades w of the disk d are erected. In the back surface, the position corresponding to the root of each blade w is raised with an arc R44, and the space between adjacent blades w is recessed with an arc R45. Here, the arcs R41 and R42 are arcs having a diameter larger than that of the arc normally provided as a fillet are, and are smoothly connected by the arc R23.

  FIG. 3 (e) shows a side where the exhaust gas G of the disk d becomes a flow path, that is, a surface on which the blades w are erected, and the base of the adjacent blades w has two inflection points. It is made into the shape connected by the curve which has p1, p2. In other words, the surface of the disk d on which the blades w are erected changes from a convex curve to a concave curve with respect to the flow direction of the exhaust gas G from the root of the blade w toward the center between the blades. The shape is connected by a curve having various inflection points. Here, the arcs R51 and R52 are referred to as fillet ares, and are necessary for mitigating local stress concentration at the blade root of the turbine impeller 11.

Returning to FIG. 1, the shaft 13 connects the turbine impeller 11 and the compressor impeller 12. The shaft center of the shaft 13 and the rotation shafts of the turbine impeller 11 and the compressor impeller 12 are concentric.
The turbine impeller 11 and the shaft 13 are integrated by welding or the like, and the compressor impeller 12 and the shaft 13 are coupled via a nut or the like.

The housing 14 surrounds the turbine impeller 11, the compressor impeller 12 and the shaft 13. The housing 14 is configured by sequentially connecting a turbine housing 21, a bearing housing 22, a seal plate 23, a compressor housing 24, and the like.
The bearing 15 rotatably supports the shaft 13 within the housing 14.

  The turbine housing 21 has an exhaust gas introduction path 31 protruding from the outer peripheral portion. The exhaust gas introduction path 31 is connected to the exhaust port E <b> 2 of the internal combustion engine E, and introduces the exhaust gas G discharged from the internal combustion engine E into the turbine housing 21. Further, an exhaust gas discharge port 32 is formed in the turbine housing 21 so as to be positioned coaxially with the shaft 13. The exhaust gas discharge port 32 is connected to an exhaust pipe (not shown) or the like.

  The bearing housing 22 fixes the position of the bearing 15. The seal plate 23 is provided between the bearing housing 22 and the compressor housing 24, and prevents air from flowing into the bearing housing 22 from the compressor housing 24.

An intake port 33 is formed in the compressor housing 24 so as to be coaxial with the shaft 13. Outside air is sucked from the intake port 33.
Further, the compressor housing 24 has a discharge flow path 34 protruding from the outer peripheral side. The discharge flow path 34 is connected to an air supply port E1 of the internal combustion engine E, and guides pressurized air to the internal combustion engine E.

  With such a configuration, the high-temperature and high-pressure exhaust gas G discharged from the internal combustion engine E is introduced into the turbine housing 21 through the exhaust gas introduction path 31 and rotates the turbine impeller 11, and then the exhaust gas discharge port 32. More exhausted to the outside. The rotation of the turbine impeller 11 is transmitted to the compressor impeller 12 through the shaft 13 to rotate the compressor impeller 12. Thus, outside air is sucked into the compressor housing 24 from the intake port 33 and compressed, and then passes through the discharge passage 34 and is supplied to the internal combustion engine E.

While the turbine impeller 11 is rotationally driven, high stress is generated near the root of the blade w. However, the disk d of the present embodiment is formed thick near the root of the blade w. The rigidity can be increased and the stress concentration can be reduced.
Moreover, since the thickness between the blades of the disk d is thin enough to satisfy the predetermined rigidity, the turbine impeller 11 of the present embodiment has a thickness near the root of the blades w. An increase in weight can be suppressed. Furthermore, since the space between the blades of the disk d of the turbine impeller 11 is reduced, loss due to collision with the exhaust gas G at the edge of the disk d is reduced, so that the efficiency can be improved.

In the present embodiment, the radial impeller of the present invention is described using the turbine impeller 11 as an example, but the same configuration may be applied to the compressor impeller 12.
Moreover, you may apply the structure like the turbine impeller 11 of this embodiment to the impeller of a mixed flow turbine or a mixed flow compressor. That is, the thickness of the disk of the mixed flow turbine or mixed flow compressor may be formed thick in the vicinity of the blade root and thin in other regions by the configuration as in the above embodiment.

It is a schematic diagram which shows the structure of the supercharger in one Embodiment of this invention. It is a perspective view showing the appearance of the turbine impeller in one embodiment of the present invention. It is an expanded view which shows a part which developed the state which looked at the disk and blade | wing of the turbine impeller in one Embodiment of this invention from the outer peripheral side of the turbine impeller. It is a schematic diagram which shows the stress concerning the disk of the conventional turbine impeller.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Supercharger, 11 ... Turbine impeller (radial impeller), d ... Disc, w ... Blade, 12 ... Compressor impeller, E ... Internal combustion engine, G ... Exhaust gas

Claims (8)

A radial impeller with a plurality of blades standing on one side of the disk,
The radial impeller is characterized in that the disc is formed to be thick in the vicinity of the blade root and thin in other regions. By raising the surface on which the blades of the disk are erected,
The radial impeller according to claim 1, wherein a thickness of the disc is formed thick in the vicinity of the blade root. By raising the back surface of the disk on which the blades are erected,
The radial impeller according to claim 1, wherein a thickness of the disc is formed thick in the vicinity of the blade root. By making the base of the adjacent blades connected by a curve formed by a combination of a plurality of arcs,
3. The radial impeller according to claim 1, wherein the disc is thick in the vicinity of the blade root and thin in another region. 4. By making the base of adjacent blades connected by a curve having a plurality of inflection points,
3. The radial impeller according to claim 1, wherein the disc is thick in the vicinity of the blade root and thin in another region. 4. By forming irregularities having radial ridgelines on the back of the surface of the disk where the blades are erected,
4. The radial impeller according to claim 1, wherein the disk is formed thick in the vicinity of the blade root and thin in another region. The radial impeller according to claim 6, wherein the contour of the unevenness is a combination of a plurality of arcs. A turbocharger that rotationally drives a turbine impeller with exhaust gas from an internal combustion engine, and that compresses and discharges outside air sucked by a compressor impeller that is coupled to the turbine impeller and rotates as the turbine impeller rotates.
The turbocharger, wherein the turbine impeller and / or the compressor impeller is a radial impeller according to any one of claims 1 to 7.

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