JP3818142B2 - Centrifugal compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a centrifugal compressor, and is intended to improve efficiency by preventing air leakage by a movable diffuser as a compressor of a supercharger for a vehicle.
[0002]
[Prior art]
In a centrifugal compressor, a diffuser part is provided between the impeller and the scroll, and the kinetic energy of the fluid discharged from the impeller is converted into pressure energy, and the flow of fluid in the diffuser part is further improved. Providing guide vanes to control the movement is performed.
[0003]
On the other hand, in a centrifugal compressor used as a supercharger for a vehicle, it is necessary to improve the performance in a wide range from a low rotation range to a high rotation range. Various types of the latter have been proposed as relatively small centrifugal compressors, which have a relatively simple structure.
[0004]
For example, a blade device composed of a blade with a large chord length and a blade with a small chord length is arranged on the inner peripheral side of the stationary blade, and a large blade or a small blade according to the operating flow rate of the compressor is placed in the diffuser flow path. Equipped with projections, guide vanes provided in the diffuser section so as to be able to project and retract, actuators for guiding or projecting the guide vanes into the diffuser section, and a controller for operating the actuator in response to the operating state of the engine In some cases, the guide vanes are protruded from the diffuser portion at high speed and high flow rate, and are controlled to be drawn from the diffuser portion at low speed and low flow rate.
[0005]
As a specific structure, for example, as shown in FIG. 4 of a centrifugal compressor disclosed in Japanese Patent Application Laid-Open No. 2000-205186, the centrifugal compressor 1 includes one of the diffuser walls 2 and 3 facing each other. A movable vane 4 that can be moved up and down is provided, and this movable vane 4 is controlled via a moving mechanism 5 from a position stored in the diffuser wall 2 to a position that contacts the other diffuser wall 3 according to the flow rate of the flow. If the movable blade 4 is completely stored, a vaneless diffuser can be obtained, and if the movable blade 4 is protruded to the maximum, a vaned diffuser can be obtained. The moving mechanism 5 can be moved by moving the movable blade 4 only in the axial direction. Easy going.
[0006]
[Problems to be solved by the invention]
However, in the centrifugal compressor in which the conventional guide vanes are taken in and out of the diffuser part, holes corresponding to the cross-sectional shape of the guide vanes are formed in the diffuser wall, and the guide vanes are taken in and out through the holes. There is a problem that a gap necessary for sliding is generated between the guide blade and the guide vane, and the efficiency of the centrifugal compressor is remarkably lowered due to air leakage from the gap.
[0007]
In addition, holes corresponding to the cross-sectional shape of the guide vanes must be formed by the number of guide vanes, which causes a problem that processing is difficult.
[0008]
The present invention has been made in view of the above-described problems of the prior art, and is intended to provide a centrifugal compressor that can prevent air leakage associated with the insertion and removal of guide vanes and can improve the efficiency of the compressor. To do.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems of the prior art, the centrifugal compressor according to claim 1 of the present invention can be taken in and out from at least one of the opposing diffuser walls of the diffuser portion communicating between the discharge side of the impeller and the scroll. A centrifugal compressor provided with guide vanes, wherein a diffuser plate that can be inserted into and removed from an annular hole formed in the one diffuser wall is provided, and a base end side surface of the guide vane is provided on the diffuser plate. In addition, a part of the other diffuser wall is formed when projecting from the front end side surface of the guide vane, and an annular crown plate is provided that closes the annular hole when immersed and constitutes the one diffuser wall. It is a feature.
[0010]
According to this centrifugal compressor, in the centrifugal compressor provided with guide vanes that can be taken in and out from at least one of the diffuser walls, a diffuser plate that can be taken in and out is provided in an annular hole formed in the one diffuser wall. The diffuser plate is provided with a base end side surface of the guide vane, and constitutes a part of the other diffuser wall when projecting to the front end side surface of the guide vane, and closes the annular hole when immersed. An annular crown plate that constitutes the diffuser wall is provided, and the diffuser plate is placed in an annular hole formed in the diffuser wall by providing guide vanes between the annular diffuser plate and the annular crown plate. Move the guide blades in and out to make the seal surface a simple annular shape. , So as to prevent air leakage closes a gap annularly diffuser plate and the crown plate.
[0011]
According to a second aspect of the present invention, in addition to the configuration according to the first aspect, the crown plate is formed in an inclined cross-sectional shape in which the diffuser portion inlet side is sharpened toward the outlet side. It is what.
[0012]
According to this centrifugal compressor, the crown plate is formed in an inclined cross-sectional shape in which the diffuser portion inlet side is sharpened and becomes thicker toward the outlet side. The flow of fluid is made smooth so as not to occur in the diffuser portion.
[0013]
Furthermore, the centrifugal compressor according to claim 3 of the present invention is provided with the fluid chamber formed in the back portion of the diffuser plate, and a fluid chamber formed in and out of the diffuser plate, in addition to the configuration according to claim 1 or 2. And a fluid drive mechanism comprising a diaphragm interlocking with the diffuser plate and a pressure fluid supplied to and discharged from the fluid chamber.
[0014]
According to this centrifugal compressor, the guide vanes are taken in and out of the fluid chamber formed in the back portion of the diffuser plate, the diaphragm provided in the fluid chamber and interlocking with the diffuser plate, and supplied to and discharged from the fluid chamber. This is done with a fluid drive mechanism consisting of pressure fluid, and the reliability is improved by applying force evenly around the guide vanes through the diaphragm, and compared with the case where a fluid pressure cylinder is used. Is trying to be compact.
[0015]
According to a fourth aspect of the present invention, in addition to the structure according to any one of the first to third aspects, the one diffuser wall is used as a hub side diffuser wall so that the diffuser plate can be taken in and out. It is characterized by this.
[0016]
According to this centrifugal compressor, the one diffuser wall is provided as a hub side diffuser wall so that the diffuser plate can be taken in and out, so that interference with a scroll or the like can be prevented compared to the case of the shroud side, It tries to be compact.
[0017]
Furthermore, the centrifugal compressor according to claim 5 of the present invention has the structure described in any one of claims 1 to 4, wherein the guide vanes are protruded from the diffuser portion on the low rotation low flow rate side so that the high rotation speed is high. It is configured to be immersed on the flow rate side.
[0018]
According to this centrifugal compressor, the guide vanes are configured to protrude into the diffuser portion on the low rotation and low flow rate side and to be immersed on the high rotation and high flow rate side. But we are trying to drive efficiently.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
1 and 2 relate to an embodiment of the centrifugal compressor according to the present invention. FIG. 1 is a partially enlarged cross-sectional view of a diffuser portion, (a) shows a state in which guide blades are projected, and (b) shows a guide. FIG. 2 shows a state in which the blades are immersed, FIG. 2 is a front view in which a part of the crown plate and the guide blade part is cut out, a state in which the upper half guide blades are projected, and a state in which the lower half guide blades are immersed. FIG.
[0020]
This centrifugal compressor is applied to, for example, a supercharger for a vehicle, and pressurizes and supplies engine intake air.
[0021]
In the centrifugal compressor 10, an impeller 12 is rotatably installed in a housing 11, and is attached to a turbine shaft driven by a turbine (not shown) so as to be rotationally driven. A scroll 13 is provided to cover the outer side of the impeller 12 in the housing 11, and a diffuser portion 14 is formed between the discharge side of the impeller 12 and the scroll 13. The diffuser portion 14 is an annular flow passage having a flow passage width defined by a pair of diffuser walls 15 and 16, and an outer peripheral cover plate 17 and an inner peripheral cover plate 18 in which one diffuser wall 15 closes the end of the scroll 13. The other diffuser wall 16 is composed of the wall surface of the housing 11. The housing 11 and the scroll 13 may be integrated.
[0022]
In the centrifugal compressor 10, guide vanes 19 that can be taken in and out of the diffuser portion 14 from the hub-side diffuser wall 15 are provided.
[0023]
The guide vanes 19 can be taken in and out through an annular hole 20 formed between the inner peripheral surface of the outer peripheral cover plate 17 and the outer peripheral surface of the inner peripheral cover plate 18 constituting one diffuser wall 15. For example, a plurality of, for example, 13 to 17 guide vanes 19 are formed integrally with the diffuser plate 21 at equal intervals around the circumference, and the base end side surface of each guide vane 19 is attached to the annular diffuser plate 21. The guide vanes 19 and the diffuser plate 21 that are in a separated state or formed separately are attached to the diffuser plate 21 via the proximal end side surfaces of the guide vanes 19.
[0024]
A stepped portion 21 a is formed on the outer periphery of the diffuser plate 21, and a stepped portion 20 a is formed on the inner periphery of the annular hole 20. When the guide vanes 19 are projected to the diffuser portion 14, the stepped portions 21 a are formed. The protruding position is regulated by abutting and air leakage is prevented.
[0025]
When the guide vanes 19 attached to the diffuser plate 21 are in an immersive state drawn from the diffuser portion 14, a corresponding space is formed between the guide vanes 19 in the annular hole 20 portion. An annular crown plate 22 is provided integrally or separately on the tip side surface of each guide vane 19.
[0026]
The crown plate 22 has a size (inner and outer diameter) that can close the annular hole 20 through which the guide vane 19 is put in and out from the diffuser portion 14 side, and the cross-sectional shape is sharp at the inlet side of the diffuser portion 14. It is formed in an inclined cross section that becomes thicker as it goes to the outlet side, the side surface on the guide blade 19 side of the crown plate 22 is a plane perpendicular to the central axis of the impeller 12, and the side surface opposite to the guide blade 19 is an inclined surface. is there.
[0027]
Corresponding to the cross-sectional shape of the crown plate 22, a concave portion 18 a into which the side surface of the pointed portion of the crown plate 22 enters is formed in the inner peripheral cover plate 18 serving as one of the diffuser walls 15. When this is done, the round plate 22 and the inner peripheral cover plate 18 forming one diffuser wall 15 of the diffuser portion 14 are made to be smoothly continuous.
[0028]
Further, the housing 11 that abuts when the guide blade 19 protrudes in a projecting state corresponding to the cross-sectional shape of the crown plate 22 is formed in an inclined cross-section opposite to the crown plate 22. A concave portion 11a into which the side surface of the pointed portion enters is formed.
[0029]
Therefore, in a state where the guide vane 19 protrudes from the diffuser portion 14, the side surface of the crown plate 22 on the guide vane 19 side constitutes the other diffuser wall 16 together with the side surface of the housing 11, and the guide vane 19 is drawn from the diffuser portion 14. In this state, the side surface of the crown plate 22 opposite to the guide vane 19 constitutes one diffuser wall 15 together with the inner and outer peripheral cover plates 17 and 18.
[0030]
As a result, in the state where the guide vanes 19 are drawn from the diffuser portion 14, the annular hole 20 is closed by the crown plate 22, air leakage can be prevented, and the efficiency of the centrifugal compressor 10 is improved.
[0031]
As a drive mechanism for taking in and out such guide vanes 19, for example, a fluid pressure drive mechanism 30 shown in the drawing is provided. In the fluid pressure drive mechanism 30, a fluid chamber 31 constituted by an annular space is provided behind the annular hole 20 and is sealed with a seal plate 32. The fluid chamber 31 is partitioned. Thus, the diaphragm 33 is attached to form two airtight chambers. A spring 35 is interposed in the diaphragm 33 via a retainer 34, and the diaphragm 33 is urged so as to protrude to the diffuser portion 14, so that it always comes into contact with the diffuser plate 21.
[0032]
Further, in the fluid pressure drive mechanism 30, a negative pressure source is connected as a pressure fluid supply device (not shown) to an airtight chamber formed behind the diaphragm 33 of the fluid chamber 31, and negative pressure is supplied / discharged via a control valve. By doing so, the diaphragm 33 can be driven back and forth so that the guide vanes 19 can be taken in and out.
[0033]
According to such a fluid pressure driving mechanism 30, the annular hole 20 for inserting and removing the guide vane 19 can be made completely airtight by the diaphragm 33, and the annular portion is formed by the step portion 21 a of the diffuser plate 21 and the crown plate 22. In combination with closing the hole, air leakage from the diffuser portion 14 can be completely prevented.
[0034]
In addition, when the diaphragm 33 can apply the force to the back surface of the diffuser plate 21 evenly on the circumference, the guide vanes 19 can be smoothly taken in and out, and the fluid pressure cylinders are provided at a plurality of locations around the circumference. Compared to the above, the amount of protrusion from the seal plate 32 can be reduced, and the size reduction can be achieved.
[0035]
In addition to the fluid pressure drive mechanism 30, a fluid pressure drive mechanism such as another fluid pressure cylinder capable of inserting / removing the guide blades or a mechanical drive mechanism such as a link or a cam may be provided.
[0036]
In the centrifugal compressor 10 configured as described above, the diaphragm 33 of the fluid pressure drive mechanism 30 is urged forward by the spring 35 so that the guide vane 19 is positioned at the diffuser portion 14 at the time of low rotation and low flow rate.
[0037]
Then, the air discharged from the impeller 12 and entering the diffuser portion 14 is, as shown in FIG. 1A, one diffuser wall 15 formed by the diffuser plate 21 and the inner and outer peripheral covers 17, 18 and the crown plate 22. And flows along the guide vane 19 between the other diffuser wall 16 formed by the housing 11 and a high pressure ratio can be obtained at the same flow rate as shown by a thick line in FIG. The efficiency can be improved.
[0038]
Further, in a state where the guide blade 19 is protruded and positioned in the diffuser portion 14, the diffuser plate 21 is fitted in the annular hole 20, and the stepped portion 21 a of the diffuser plate 21 is formed in the hole 20. Air leakage is prevented by coming into contact with the stepped portion 20a. Further, since the diaphragm 33 of the fluid chamber 31 is in an airtight state, air leakage is completely prevented.
[0039]
In the state in which the crown plate 22 is in contact with the housing 11, the inlet side of the diffuser portion 14 of the crown plate 22 is sharpened, and further enters the recess 11 a of the housing 11, so that it is discharged from the impeller 12. Smooth air flow.
[0040]
Further, in the centrifugal compressor 10, when the rotation speed is high and the flow rate is high, the diaphragm 33 of the fluid pressure driving mechanism 30 is pulled back backward by the negative pressure against the spring 35, and the guide blade 19 is drawn from the diffuser portion 14. To do.
[0041]
Then, the air discharged from the impeller 12 and entering the diffuser portion 14 is caused by the one diffuser wall 15 formed by the crown plate 22 and the inner and outer peripheral covers 17 and 18 and the housing 11 as shown in FIG. As shown by a thin line in FIG. 3, a high pressure ratio can be obtained at the same flow rate, and the centrifugal compressor 10 has a high pressure ratio. Efficiency can be improved.
[0042]
Further, when the guide blade 19 is immersed and retracted from the diffuser portion 14, the annular hole 20 is closed by the crown plate 22, so that air leakage is prevented, and the diaphragm of the fluid chamber 31 is further prevented. Since the airtight state is established at 33, air leakage is completely prevented.
[0043]
Further, in the state where the annular hole 20 is closed with the crown plate 22, the inlet side of the diffuser portion 14 of the crown plate 22 is sharpened, and furthermore, enters the recess 18 a of the inner peripheral cover plate 18. The air discharged from the impeller 12 can flow smoothly.
[0044]
Therefore, in such a centrifugal compressor 10, in the performance curve shown in FIG. 3, the guide vane 19 protrudes from the diffuser portion 14 and is immersed, with the same flow rate at the same rotational speed. If the guide vanes 19 are put in and out at the intersection where the pressure ratio is the same, it is possible to always operate in an efficient state over a wide range from the low rotation range to the high rotation range.
[0045]
Further, in this centrifugal compressor 10, since the holes for taking in and out the guide vanes 19 are formed in an annular shape without forming the corresponding number of holes corresponding to the cross-sectional shape of the guide vanes 19, the processing is easy and the gaps are eliminated. It is possible to easily increase the accuracy of the air and to easily seal against air leakage.
[0046]
In the above embodiment, the guide vanes are provided on the diffuser wall on the hub side. However, if there is no problem in terms of space, the guide vanes may be provided on the diffuser wall on the shroud side.
[0047]
In the above embodiment, the centrifugal compressor applied to the vehicle supercharger has been described as an example. However, the present invention can be similarly applied as a centrifugal compressor when operating in another wide rotation range.
[0048]
【The invention's effect】
As described above in detail with reference to one embodiment, according to the centrifugal compressor of claim 1 of the present invention, the centrifugal compressor provided with guide vanes that can be taken in and out from at least one of the diffuser walls, A diffuser plate that can be inserted into and removed from an annular hole formed in the diffuser wall is provided, and a base end side surface of the guide vane is provided on the diffuser plate, and the other diffuser wall is projected when protruding from the front end side surface of the guide vane. In addition, the annular hole is closed to close the annular hole and the annular crown plate that constitutes the one diffuser wall is provided at the time of immersion, so that the guide vanes are provided with the annular diffuser plate and the annular annular plate. The diffuser plate is moved in an annular hole formed between the crown plates and formed in the diffuser wall. And in can and out of the guide vanes, as well as the shape of the sealing surface in a simple annular, it is possible to prevent air leakage closes a gap annularly diffuser plate and the crown plate.
[0049]
This facilitates processing of the holes necessary for inserting and removing the guide vanes, prevents air leakage, and improves the efficiency of the centrifugal compressor.
[0050]
According to the centrifugal compressor according to claim 2 of the present invention, since the crown plate is formed in an inclined cross-sectional shape in which the diffuser portion inlet side is sharpened toward the outlet side, the guide vanes are taken in and out. In any state, the flow of the fluid can be made smooth by preventing a step due to the crown plate from occurring in the diffuser portion, and the operation can be performed efficiently.
[0051]
Furthermore, according to the centrifugal compressor according to claim 3 of the present invention, a fluid chamber formed in the back portion of the diffuser plate for taking in and out of the guide blade, and a diaphragm provided in the fluid chamber and interlocking with the diffuser plate, Since the fluid drive mechanism is composed of the pressure fluid supplied to and discharged from the fluid chamber, reliability is improved by applying force evenly around the guide blades through the diaphragm, and the fluid The mechanism can be made more compact than when a pressure cylinder or the like is used, and air leakage can be completely prevented by the diaphragm.
[0052]
In the centrifugal compressor according to claim 4 of the present invention, the one diffuser wall is used as a hub side diffuser wall so that the diffuser plate can be inserted and removed. Interference can be prevented and downsizing can be achieved.
[0053]
Furthermore, according to the centrifugal compressor according to claim 5 of the present invention, the guide vanes are configured to protrude into the diffuser portion on the low rotation and low flow rate side and to be immersed on the high rotation and large flow rate side. Efficient operation is possible on the flow rate side and on the high rotation / high flow rate side.
[Brief description of the drawings]
FIG. 1 is a partial enlarged cross-sectional view of a diffuser portion according to an embodiment of the centrifugal compressor of the present invention, where (a) shows a state in which guide vanes protrude and (b) shows a state in which guide vanes are immersed. Respectively.
FIG. 2 is a front view of a guide blade portion and a crown plate according to an embodiment of the present invention, in which a part of the crown plate is cut away, and the upper half guide blade is projected, and the lower half guide blade is immersed. It is the longitudinal cross-sectional view made into the made state.
FIG. 3 is a performance characteristic diagram of a state in which the guide vanes are protruded and a state in which the guide vanes are immersed according to the embodiment of the centrifugal compressor of the present invention.
FIG. 4 is a partially enlarged cross-sectional view of a diffuser portion according to a conventional centrifugal compressor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Centrifugal compressor 11 Housing 11a Recess 12 Impeller 13 Scroll 14 Diffuser part 15 Diffuser wall 16 Diffuser wall 16 Diffuser wall 17 Outer cover plate 18 Inner cover cover 19 Guide vane 20 Annular hole 20a Step part 21 Diffuser plate 21a Step part 22 Crown plate 30 Fluid pressure drive mechanism 31 Fluid chamber 32 Seal plate 33 Diaphragm 34 Retainer 35 Spring

Claims (5)

A centrifugal compressor provided with guide vanes that can be taken in and out from at least one of the opposing diffuser walls of the diffuser portion communicating between the discharge side of the impeller and the scroll,
A diffuser plate that can be inserted into and removed from an annular hole formed in the one diffuser wall is provided, and a base end side surface of the guide vane is provided on the diffuser plate, while the other end of the guide vane is projected when protruding to the other side. A centrifugal compressor comprising a part of a diffuser wall and an annular crown plate for closing the annular hole and forming the one diffuser wall when immersed. The centrifugal compressor according to claim 1, wherein the crown plate is formed in an inclined cross-sectional shape in which a diffuser portion inlet side is sharpened and becomes thicker toward an outlet side. A fluid drive mechanism comprising a fluid chamber formed at the back of the diffuser plate, a diaphragm that is provided in the fluid chamber and that is linked to the diffuser plate, and a pressure fluid that is supplied to and discharged from the fluid chamber. The centrifugal compressor according to claim 1 or 2, wherein The centrifugal compressor according to any one of claims 1 to 3, wherein the one diffuser wall is provided as a hub side diffuser wall so that the diffuser plate can be taken in and out. The centrifugal compressor according to any one of claims 1 to 4, wherein the guide vanes are configured to protrude into the diffuser portion at a low rotation and low flow rate side and to be immersed at a high rotation and high flow rate side.

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