JP2011196256A - Rotor and supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor reducing a manufacturing cost and a supercharger equipped with the rotor.SOLUTION: The rotor 5 is a rotor in which a rotary vane 7 and a support shaft 6 are integrally connected, and has a construction in which the support shaft 6 has a fitting recess 62 formed in an end face 61 in the axial direction, the rotary vane 7 is molded using a heat resistant alloy and has a fitting projection 71 projecting in the axial direction, and the fitting projection 71 is fitted into the fitting recess 62.

Description

 The present invention relates to a rotor composed of a rotor blade and a support shaft, and a supercharger including the rotor, which are suitable for reducing manufacturing costs.

 2. Description of the Related Art Conventionally, a supercharger that improves the performance of an internal combustion engine by compressing air using the energy of exhaust gas introduced from the internal combustion engine and supplying the compressed air to the internal combustion engine in a vehicle, a ship, or the like. in use. In such a supercharger, a rotor is used in which a rotor blade and a support shaft are integrally connected and rotated by the flow of exhaust gas. Since high-temperature exhaust gas flows around the rotor blade, the rotor blade is formed using a material having high heat resistance, such as a nickel-based heat-resistant alloy. On the other hand, the support shaft that is not in direct contact with the exhaust gas is formed using a general material having high rigidity, for example, chromium molybdenum steel.

 In addition, since the rotor rotates at a high speed due to the flow of exhaust gas, the rotation center of the rotor blade (that is, the center of gravity of the rotor blade) Therefore, it is required to accurately position the axis of the support shaft. For example, in the rotor shown in Patent Document 1, a convex portion is provided on the end surface in the axial direction of the support shaft, a concave portion that can be fitted to the convex portion is provided on the rotor blade, and the convex portion is fitted into the concave portion. The rotation center of the rotor blade and the shaft center of the support shaft are positioned with high accuracy. In addition, after fitting a recessed part in a convex part and connecting a rotor blade and a support shaft integrally, adjustment (grinding etc.) with respect to a rotor blade is performed in order to improve the balance as the whole rotor.

Japanese Patent No. 3293712 (3rd page, Fig. 3)

However, the following problems exist in the conventional technology as described above.
The concave portion in the rotary blade is formed by cutting. Here, when forming a rotor blade using a nickel-based heat-resistant alloy, since the heat-resistant alloy is a hard and tough hard-to-cut material, the cutting tool that forms the recess is consumed quickly, and the tool life is extremely short. It was getting shorter. For this reason, there is a problem that high cost is required for forming the rotor blades.

 In addition, since the above heat-resistant alloy is a difficult-to-cut material, the machining accuracy of the concave portion in the rotor blade is not stable, and the inner diameter of the concave portion is a size that takes into account the variation due to the machining to the outer diameter of the convex portion of the support shaft. It was processed. Therefore, there is a problem that it is difficult to stabilize the positioning accuracy between the rotation center of the rotor blade and the shaft center of the support shaft when the convex portion is fitted in the concave portion. Furthermore, since it is difficult to stabilize the positioning accuracy, a large adjustment is required in the adjustment process performed after connecting the rotor blade and the support shaft, and an excessive adjustment amount becomes a defective product. The defect rate of the rotor also increased, resulting in a problem that the manufacturing cost of the rotor increased.

 The present invention has been made in view of the above points, and an object of the present invention is to provide a rotor capable of reducing manufacturing costs and a supercharger including the rotor.

In order to solve the above problems, the present invention employs the following means.
A rotor according to the present invention is a rotor in which a rotor blade and a support shaft are integrally connected, the support shaft has a fitting recess formed in an end surface in the axial direction, and the rotor blade is a heat-resistant alloy. It has a fitting convex part which is shape | molded using and protrudes in an axial direction, and the structure that a fitting convex part is fitted to the fitting recessed part is employ | adopted.

In the present invention employing such a configuration, the processing surfaces of the fitting convex portion formed on the rotary blade are the outer peripheral surface and the end surface, and the concave portion formed on the conventional rotary blade is the inner peripheral surface, the end surface and Compared to the processing of the outer peripheral surface, the number of places requiring processing is reduced. Therefore, the consumption of the cutting tool is suppressed and the tool life is extended.
Further, in the present invention, it is easier to form the fitting convex portion on the rotor blade than to form the concave portion on the conventional rotor blade, so that the processing accuracy of the fitting convex portion is more stable. On the other hand, a fitting recess is formed in the support shaft. However, since the material of the support shaft is a material having better machinability than the heat-resistant alloy of the rotor blade, compared to forming the recess in the rotor blade. Processing accuracy is stable. As a result, the positioning accuracy between the rotation center of the rotary blade and the axis center of the support shaft when the fitting convex portion is fitted into the fitting concave portion is improved.

Further, the rotor according to the present invention is provided with a large-diameter portion larger in diameter than the fitting convex portion at the base end portion of the fitting convex portion in the rotor blade, and the outer diameter of the large diameter portion is the fitting concave portion of the support shaft. A configuration is adopted in which the outer diameter is substantially the same as the outer diameter at the side end.
In the present invention employing such a configuration, the outer diameter of the large diameter portion is substantially the same as the outer diameter at the end portion of the support shaft, so that the outer periphery of the portion where the large diameter portion and the end portion are in contact with each other The surface side is substantially flush. In addition to this, since the large-diameter portion is provided, the contact portion between the large-diameter portion and the end portion is separated from the rotor blade toward the support shaft, and the connection work at the contact portion can be easily performed. It becomes possible.

Moreover, the rotor which concerns on this invention employ | adopts the structure that the contact part of a large diameter part and an edge part is welded.
In the present invention employing such a configuration, since the large-diameter portion is provided, the contact portion between the large-diameter portion and the end portion is separated from the rotor blade toward the support shaft, and welding work at the contact portion is performed. Can be easily performed.

Moreover, the supercharger which concerns on this invention employ | adopts the structure provided with the rotor as described in any one of Claim 1 to 3.
In the present invention employing such a configuration, the consumption of the cutting tool is suppressed, and the tool life is extended. Further, in the present invention, the processing accuracy of the fitting convex portion in the rotary blade is stable, and the processing accuracy of the fitting concave portion in the support shaft is also stable as compared with the case where the concave portion is formed in the conventional rotary blade. As a result, the positioning accuracy between the rotation center of the rotor blade and the axis center of the support shaft is improved.

According to the present invention, the following effects can be obtained.
According to the present invention, since the tool life in cutting is extended, there is an effect that the manufacturing cost of the rotor and the manufacturing cost of the supercharger including the rotor can be reduced. In addition, since the positioning accuracy between the rotation center of the rotor blade and the shaft center of the support shaft is improved, the adjustment amount in the adjustment process performed after the connection between the rotor blade and the support shaft is reduced, and the defect rate of the rotor is also reduced. Therefore, there is an effect that the manufacturing cost of the rotor and the manufacturing cost of the supercharger including the rotor can be reduced.

1 is a schematic diagram showing an overall configuration of a supercharger T. FIG. 3 is a schematic diagram showing a configuration of a rotor 5. FIG. FIG. 6 is a schematic view showing a modification of the rotor 5.

 Hereinafter, embodiments of a rotor and a supercharger according to the present invention will be described with reference to FIGS. 1 to 3. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size. Moreover, the arrow F in each drawing shall show a front direction.

The overall configuration of the supercharger T according to this embodiment will be described with reference to FIG.
FIG. 1 is a schematic diagram showing the overall configuration of the supercharger T.
The supercharger T compresses air using the energy of exhaust gas guided from an internal combustion engine (not shown), and supplies the compressed air to the internal combustion engine, thereby improving the performance of the internal combustion engine such as output and fuel consumption. It is something to be made. The supercharger T has a turbine housing 1, a bearing housing 2, a seal plate 3, and a compressor housing 4, and these members are sequentially arranged from the front side and integrally provided. .

 Further, a rotor 5 that rotates by the flow of exhaust gas is installed inside the supercharger T. The rotor 5 is connected to a turbine shaft (support shaft) 6 that is a shaft member, a turbine impeller (rotary blade) 7 that is a rotor blade connected to a front end portion of the turbine shaft 6, and a rear end portion of the turbine shaft 6. And a compressor impeller 8 which is a rotating blade. The turbine impeller 7 is disposed in the turbine housing 1, and the compressor impeller 8 is disposed in the compressor housing 4.

The turbine housing 1 is a member in which the energy of exhaust gas is converted into the rotational driving force of the rotor 5. The turbine housing 1 has a turbine scroll passage 11 and a turbine housing outlet 12.
The turbine scroll channel 11 is a channel into which exhaust gas from the internal combustion engine is introduced, and is a substantially annular channel provided so as to surround the turbine impeller 7. Further, the turbine scroll passage 11 communicates with the installation location of the turbine impeller 7 at the radially inner portion. The turbine housing outlet 12 is provided on the front side of the turbine impeller 7 and is an exhaust port for discharging exhaust gas after rotating the turbine impeller 7 from the turbine housing 1.

The bearing housing 2 is a member that rotatably supports the turbine shaft 6 of the rotor 5. The bearing housing 2 rotatably supports the turbine shaft 6 extending in the front-rear direction via a pair of bearings 21. In the bearing housing 2, lubricating oil for lubricating the bearing 21 and the turbine shaft 6 is supplied.
The seal plate 3 is a substantially disk-shaped member, prevents leakage of the lubricating oil supplied into the bearing housing 2 to the compressor housing 4 side, and a later-described diffuser passage between the compressor housing 4 and the seal plate 3. 42 is formed.

The compressor housing 4 is a member that compresses air introduced from the outside, and has an air inlet 41, a diffuser flow path 42, and a compressor scroll flow path 43.
The air inlet 41 is an inlet for introducing air into the compressor housing 4, and is provided on the rear side of the compressor impeller 8. The diffuser channel 42 is a substantially annular channel provided so as to surround the compressor impeller 8, and is a channel in which air sent out by the rotation of the compressor impeller 8 is compressed. The compressor scroll passage 43 is a substantially annular passage provided so as to surround the compressor impeller 8, and is a passage into which air compressed in the diffuser passage 42 is introduced. The compressor scroll flow path 43 is connected to an air discharge port (not shown), and the compressed air is discharged from the air discharge port and supplied to the intake port of the internal combustion engine.

Next, the configuration of the rotor 5 according to the present embodiment will be described in detail with reference to FIGS. 1 and 2.
2A and 2B are schematic views showing the configuration of the rotor 5, where FIG. 2A is a side view of the rotor 5, FIG. 2B is a side view of the turbine shaft 6, and FIG. 2C is a side view of the turbine impeller 7. In FIG. 2, the description of the compressor impeller 8 is omitted.

 As shown in FIG. 1, the rotor 5 is rotated by the flow of exhaust gas introduced into the turbine housing 1, and includes a turbine shaft 6, a turbine impeller 7, and a compressor impeller 8.

 The turbine shaft 6 is a shaft member that extends in the front-rear direction and connects the turbine impeller 7 and the compressor impeller 8. The turbine shaft 6 is formed by cutting or the like using chromium molybdenum steel or the like having high rigidity. Further, as described above, the turbine shaft 6 is rotatably supported by the bearing housing 2 via the pair of bearings 21.

 As shown in FIG. 2, the front end surface 61 in the front-rear direction (that is, the axial direction) of the turbine shaft 6 is formed in a planar shape perpendicular to the front-rear direction. The end surface 61 is used for connection with the turbine impeller 7 and is formed with a fitting recess 62 having a circular shape when viewed from the front. The inner diameter of the fitting recess 62 is formed to be the same inner diameter in the front-rear direction. A male screw portion 63 used for connection to the compressor impeller 8 is provided at the rear end portion of the turbine shaft 6.

 There are three places on the end portion 64 of the turbine shaft 6 where the fitting recess 62 is formed, which are the end surface 61, the fitting recess 62, and the outer peripheral surface of the end portion 64. The fitting recess 62 is formed by processing a recess inner peripheral surface 62a and a bottom surface 62b facing forward. In particular, since the concave inner peripheral surface 62a is related to the positioning accuracy between the turbine shaft 6 and the turbine impeller 7 in the direction orthogonal to the axial direction of the turbine shaft 6, high machining accuracy is required.

The turbine impeller 7 is a rotary blade that rotates in response to the flow of exhaust gas, and is integrally connected to the front end portion of the turbine shaft 6. The turbine impeller 7 has a configuration in which a plurality of blades are arranged in the circumferential direction on the outer peripheral surface of a hub formed in a substantially conical shape, and is formed using a nickel-based heat-resistant alloy that is a difficult-to-cut material. Has been.
Further, the turbine impeller 7 has a fitting convex portion 71 that protrudes rearward and can be fitted into the fitting concave portion 62 without a gap in a rear view. The outer diameter of the fitting convex part 71 is formed so that it may become the same outer diameter regarding the front-back direction.

The turbine shaft 6 and the turbine impeller 7 are integrally connected by welding at a contact portion W between the turbine impeller 7 and the end surface 61 of the turbine shaft 6 with the fitting convex portion 71 fitted in the fitting concave portion 62. ing. As the welding, electron beam welding, laser welding, or the like is used.
The turbine impeller 7 is formed using precision casting, and the fitting convex portion 71 is formed by cutting after casting.

 There are two places on the fitting convex portion 71 where cutting is performed: a convex portion outer peripheral surface 71a and a convex portion end surface 71b. In particular, the convex outer peripheral surface 71a is required to have high machining accuracy because it is related to the positioning accuracy between the turbine shaft 6 and the turbine impeller 7 in the direction orthogonal to the axial direction of the turbine shaft 6.

 As shown in FIG. 1, the compressor impeller 8 is a rotary blade that rotates in synchronization with the turbine impeller 7 and sends out the air introduced from the air introduction port 41 to the outside in the radial direction by the rotation. It has the same configuration. The compressor impeller 8 is integrally connected to the rear end portion of the turbine shaft 6 using a fastening member (bolt).

Then, the effect | action of this embodiment regarding the connection of the turbine shaft 6 and the turbine impeller 7 is demonstrated.
As described above, since the turbine impeller 7 is formed using a hard-to-cut nickel-based heat-resistant alloy, the tool for cutting tends to be consumed quickly. But in this embodiment, the location of the cutting process for forming the fitting convex part 71 in the turbine impeller 7 is two places, the convex outer peripheral surface 71a and the convex part end surface 71b. This is because the recesses formed in the conventional turbine impeller are reduced in the number of places that require machining as compared with the case where the inner circumferential surface, the end surface, and the outer circumferential surface are cut. Therefore, the consumption of the cutting tool is suppressed and the tool life is extended. Therefore, the cost for manufacturing the rotor 5 having the turbine impeller 7 is reduced.

Moreover, in this embodiment, since it is easier to form the fitting convex part 71 in the turbine impeller 7 than to form a recessed part in the conventional turbine impeller, the processing precision of the fitting convex part 71 becomes more stable. . On the other hand, although the fitting recess 62 is formed in the turbine shaft 6, because the material of the turbine shaft 6 is made of chromium molybdenum steel or the like, it is a material having better machinability than the nickel heat-resistant alloy of the turbine impeller 7. In addition, the machining accuracy is stable as compared with the case where the recess is formed in the turbine impeller. Therefore, the reference dimensions of the outer diameter of the fitting convex portion 71 and the inner diameter of the fitting concave portion 62 can be made closer to each other, and each can be formed with a narrower tolerance. As a result, the positioning accuracy between the rotation center of the turbine impeller 7 and the shaft center of the turbine shaft 6 when the fitting convex portion 71 is fitted to the fitting concave portion 62 is improved.
Since the positioning accuracy is improved in this way, the adjustment amount in the adjustment process for improving the balance of the rotor 5 as a whole performed after connecting the turbine shaft 6 and the turbine impeller 7 is reduced, and The defective rate of the rotor 5 also decreases. Therefore, the cost for manufacturing the rotor 5 is reduced.

Therefore, according to the present embodiment, the following effects can be obtained.
According to this embodiment, since the tool life in cutting is extended, there is an effect that the manufacturing cost of the rotor 5 and the manufacturing cost of the supercharger T including the rotor 5 can be reduced. Further, since the positioning accuracy between the rotation center of the turbine impeller 7 and the shaft center of the turbine shaft 6 is improved, the amount of adjustment in the adjustment process performed after the connection between the turbine impeller 7 and the turbine shaft 6 is reduced, and the rotor 5 Therefore, there is an effect that the manufacturing cost of the rotor 5 and the manufacturing cost of the supercharger T including the rotor 5 can be reduced.

 As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples 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, you may apply the modification shown in FIG. 3 to the rotor 5 in the said embodiment.
FIG. 3 is a schematic view showing a modification of the rotor 5.
As shown in FIG. 3, the base end portion of the fitting convex portion 71 in the turbine impeller 7, that is, between the hub of the turbine impeller 7 and the fitting convex portion 71, has a larger diameter than the fitting convex portion 71. A diameter portion 72 is provided. The outer diameter of the large diameter portion 72 is substantially the same as the outer diameter of the end portion 64 in the turbine shaft 6. And the 2nd contact part W2 (contact part) of the large diameter part 72 and the edge part 64 is welded. By this welding, the turbine shaft 6 and the turbine impeller 7 are integrally connected.
In such a modification, since the outer diameter of the large diameter portion 72 is substantially the same as the outer diameter of the end portion 64, the outer peripheral surface side of the second contact portion W2 is substantially flush. In addition to this, since the large-diameter portion 72 is provided, the second contact portion W2 is separated from the hub of the turbine impeller 7 toward the turbine shaft 6, and for example, an electron beam for welding, a laser, or the like is applied to the turbine shaft 6. Since it can irradiate from the direction orthogonal to an axis line, it becomes possible to perform the welding operation in the 2nd contact part W2 easily.

 DESCRIPTION OF SYMBOLS 5 ... Rotor, 6 ... Turbine shaft (support shaft), 61 ... End surface, 62 ... Fitting recessed part, 64 ... End part, 7 ... Turbine impeller (rotary blade), 71 ... Fitting convex part, 72 ... Large diameter part, T ... supercharger, W2 ... second contact part (contact part)

Claims (4)

A rotor in which a rotor blade and a support shaft are integrally connected,
The support shaft has a fitting recess formed on the end surface in the axial direction,
The rotor blade is formed using a heat-resistant alloy and has a fitting protrusion that protrudes in the axial direction.
The fitting convex portion is fitted in the fitting concave portion. The rotor according to claim 1, wherein
The base end portion of the fitting convex portion in the rotor blade is provided with a large diameter portion larger in diameter than the fitting convex portion,
The outer diameter of the large diameter portion is substantially the same as the outer diameter at the end of the support shaft on the fitting recess side. The rotor according to claim 2, wherein
A rotor in which a contact portion between the large diameter portion and the end portion is welded. A turbocharger comprising the rotor according to any one of claims 1 to 3.

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