JP3818202B2 - Centrifugal compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a centrifugal compressor, and as a compressor for a vehicle supercharger, the efficiency is improved by preventing air leakage by a movable diffuser, and the operating range on the low flow rate side is widened, and the efficiency on the high flow rate side is increased. It is intended to be improved.
[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 long 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 protrudes into the diffuser passage according to the operating flow rate of the compressor. A guide vane that can be projected and retracted into the diffuser section, an actuator that projects or retracts the guide vane into the diffuser section, and a controller that operates the actuator in response to the operating state of the engine, There is a control that causes the guide vanes to protrude from the diffuser portion at high speed and high flow rate, and to be retracted from the diffuser portion at low speed and low flow rate.
[0005]
As a specific structure, for example, as shown in FIG. 5 of a centrifugal compressor disclosed in Japanese Patent Application Laid-Open No. 2000-205186, the centrifugal compressor 1 includes one of the diffuser passage walls 2 and 3 facing each other. A movable vane 4 that can freely move in and out of the wall 2 is provided, and the movable vane 4 is moved from a position stored in the diffuser passage wall 2 to a position where it abuts against the other diffuser passage wall 3 through a moving mechanism 5 according to the flow rate of the flow. If the movable blade 4 is completely retracted, it can be a diffuser without a blade, and if the movable blade 4 is fully projected, a diffuser with a blade can be obtained. By moving the movable blade 4 only in the axial direction, The moving mechanism 5 is simplified.
[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 portion, holes corresponding to the cross-sectional shape of the guide vanes are formed in the diffuser passage 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 hole and the guide vane, and the efficiency of the centrifugal compressor is significantly reduced 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]
Furthermore, in general, in order to improve the performance of the centrifugal compressor itself, it is necessary to widen the passage width of the diffuser section on the high flow rate side, but on the contrary, the passage width of the diffuser section is narrowed to widen the operating area on the low flow rate side. There is a conflicting problem that must be made, and development of a centrifugal compressor that can satisfy both of these problems is desired.
[0009]
The present invention has been made in view of the problems and demands of the prior art described above, and can prevent air leakage associated with the insertion and removal of the guide vanes, improve the efficiency of the compressor, and reduce the low flow rate side. Therefore, the present invention intends to provide a centrifugal compressor capable of expanding the operating range in the above and improving the efficiency on the high flow rate side.
[0010]
[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 passage walls of the diffuser portion communicating between the discharge side of the impeller and the scroll. A centrifugal compressor provided with various guide vanes, wherein a diffuser plate that can be taken in and out of an annular hole formed in the one diffuser passage wall is provided, and a base end side surface of the guide vane is provided on the diffuser plate. On the other hand, an annular crown plate that constitutes a part of the other diffuser passage wall when projecting from the tip side surface of the guide vane and closes the annular hole at the time of immersion and constitutes the one diffuser passage wall is provided. Provided, and the passage width of the diffuser portion is changed between when the guide blade protrudes and when it is immersed A.
[0011]
According to this centrifugal compressor, a centrifugal compressor provided with guide vanes that can be taken in and out from at least one of the diffuser passage walls is provided with a diffuser plate that can be taken in and out in an annular hole formed in the one diffuser passage wall. In addition, the diffuser plate is provided with a base end side surface of the guide vane, and forms a part of the other diffuser passage wall when projecting to the front end side surface of the guide vane and closes the annular hole when immersed. An annular crown plate constituting the one diffuser passage wall is provided to change the passage width of the diffuser portion when the guide vane protrudes and when it is immersed, and the guide vane is connected to the annular diffuser plate and the circle. A diffuser plug is installed in an annular hole formed in the diffuser passage wall between the annular crown plates. The guide blade is moved in and out by moving the guide, and the shape of the seal surface is made into a simple annular shape, and the annular gap is closed by the diffuser plate and the crown plate to prevent air leakage. By changing the passage width of the diffuser part between the time of protrusion and the time of immersion, the operating area is widened on the low flow rate side, and the efficiency is improved on the high flow rate side independently or simultaneously so that both can be achieved.
[0012]
According to a second aspect of the present invention, in addition to the configuration according to the first aspect, the guide vanes protrude from the diffuser portion on the low rotation and low flow rate side and are immersed on the high rotation and large flow rate side. In addition to the construction, the passage width of the diffuser portion at the time of protrusion is narrower than that at the time of immersion.
[0013]
According to this centrifugal compressor, the guide vanes are configured to protrude into the diffuser portion at the low rotation and low flow rate side and to be immersed at the high rotation and large flow rate side, and the passage width of the diffuser portion at the time of protrusion is greater than that at the time of immersion. Therefore, it is possible to efficiently operate on both the low rotation and low flow rate sides and the high rotation and large flow rate side, and to expand the operating range on the low flow rate side and to improve the efficiency on the high flow rate side.
[0014]
Furthermore, in the centrifugal compressor according to claim 3 of the present invention, in addition to the configuration according to claim 1 or 2, the passage width of the diffuser portion is changed depending on the distance between the diffuser plate and the crown plate and the shape of the crown plate. It is characterized by comprising.
[0015]
According to this centrifugal compressor, the passage width of the diffuser portion is configured to change depending on the distance between the diffuser plate and the crown plate and the shape of the crown plate, and even when the guide vanes are taken in and out, the passage of the diffuser portion can be easily performed. The width can be changed.
[0016]
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.
[0017]
This centrifugal compressor is applied to, for example, a supercharger for a vehicle, and pressurizes and supplies engine intake air.
[0018]
In the centrifugal compressor 10, an impeller 12 is rotatably supported in a housing 11, and is attached to a turbine shaft driven by a turbine (not shown) so as to be driven to rotate. 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 formed in an annular shape with a width defined by a pair of opposing diffuser passage walls 15, 16, and an outer peripheral cover plate 17 and an inner cover plate 17 in which one hub-side diffuser passage wall 15 closes the end of the scroll 13. The other diffuser passage wall 16 is formed by the wall surface of the housing 11. The housing 11 and the scroll 13 may be integrated.
[0019]
In the centrifugal compressor 10, guide vanes 19 that can be taken in and out of the diffuser portion 14 from the diffuser passage wall 15 on the hub side are provided.
[0020]
This guide vane 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 passage wall 15. For example, a plurality of guide blades 19, for example, 13 to 17 guide blades 19 are formed integrally with the diffuser plate 21 at equal intervals around the circumference, and the base end side surface of each guide blade 19 is attached to the annular diffuser plate 21. The guide vanes 19 and the diffuser plate 21 which are in a state of being formed or formed separately are attached to the diffuser plate 21 via the base end side surfaces of the respective guide vanes 19.
[0021]
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.
[0022]
Instead of the stepped portion 21 a on the outer periphery of the diffuser plate 21, a stepped portion may be formed on the inner periphery, and the guide vane 19 protrudes from the diffuser portion 14 with the stepped portion formed on the inner periphery of the annular hole 20. The protruding positions may be regulated by bringing them into contact with each other and air leakage may be prevented.
[0023]
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.
[0024]
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.
[0025]
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 passage walls 15, and the guide vanes 19 are drawn to be immersed. In this case, the round plate 22 and the inner peripheral cover plate 18 forming one diffuser passage wall 15 of the diffuser portion 14 are smoothly continuous.
[0026]
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.
[0027]
As a result, in the state where the guide vanes 19 are drawn from the diffuser portion 14, the annular hole 20 is blocked by the crown plate 22, air leakage can be prevented, and the efficiency of the centrifugal compressor 10 is improved.
[0028]
In the centrifugal compressor 10, the passage width B of the diffuser portion 14 is changed between a state in which the guide vane 19 protrudes from the diffuser portion 14 and a state in which the guide vane 19 is drawn from the diffuser portion 14. As shown in FIG. 1A, the passage width B in a state in which the guide vane 19 protrudes from the diffuser portion 14 is narrowed to b1, and as shown in FIG. 1B, the guide vane 19 is moved to the diffuser portion 14. The passage width B in the state of being pulled in is made wide with b2.
[0029]
For this reason, as shown in FIG. 1 (a), in the state where the guide vane 19 protrudes from the diffuser portion 14, the passage width B = b1 of the diffuser portion 14 is determined by the width of the guide vane 19 itself. Since the other end is determined by the base end side surface (inner side surface) of the guide vane 19 of the plate 22 and the tip end side surface of the guide vane 19 of the diffuser plate 21, the crown plate 22 is brought into contact with the housing 11. The guide blade 19 is formed so that the tip side surface protrudes into the diffuser portion 14 more than the inner and outer peripheral cover plates 17 and 18, thereby narrowing the passage width B to b1 and narrowing it by protruding the hub side.
[0030]
As shown in FIG. 1B, when the guide vane 19 is pulled from the diffuser portion 14, the passage width B = b2 of the diffuser portion 14 is outside of the crown plate 22 on the opposite side to the guide vane 19. Since the other side is determined as the side surface of the diffuser portion 14 of the housing 11, the outer surface of the crown plate 22 and the inner surface of the housing 11 are brought into contact with the inner and outer peripheral cover plates 17 and 18. Is set to a thickness which is one of the shapes of the crown plate 22 so that the width of the passage is as wide as passage width B = b2.
[0031]
Therefore, in the state where the guide vanes 19 are projected from the diffuser portion 14, the inner surface of the crown plate 22 on the guide vane 19 side constitutes the other diffuser passage wall 16 together with the side surface of the housing 11, and the guide vanes 19 are connected to the diffuser portion 14. In this state, the outer surface of the crown plate 22 opposite to the guide vanes 19 constitutes one diffuser passage wall 15 together with the inner and outer peripheral cover plates 17 and 18.
[0032]
As a structure for changing the passage width B of the diffuser portion 14 as shown in FIGS. 3A and 3B, when the passage width B is narrowed to b1, the diffuser plate 21 on the hub side is changed. Instead of protruding, the crown plate 22 may be protruded into the diffuser portion 14 and squeezed on the shroud side.
[0033]
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.
[0034]
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.
[0035]
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 20, the air leakage from the diffuser portion 14 can be completely prevented.
[0036]
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.
[0037]
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.
[0038]
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.
[0039]
Then, the air discharged from the impeller 12 and entering the diffuser portion 14 is, as shown in FIG. 1A, one diffuser passage wall 15 formed by the diffuser plate 21 and the inner and outer peripheral covers 17, 18, and the crown plate. As shown by the solid line in FIG. 4, the passage width of the diffuser section flows along the guide vanes 19 of the diffuser section 14 whose path width B with the other diffuser passage wall 16 formed by 22 is narrowed to b1. Compared with the broken line in FIG. 4 which shows the case where it is constant without changing, the surge line moves to the low flow rate side, and the usable range on the low rotation low flow side of the centrifugal compressor 10 can be expanded. .
[0040]
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.
[0041]
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.
[0042]
On the other hand, 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 vanes 19 are drawn from the diffuser portion 14. To do.
[0043]
Then, the air that is discharged from the impeller 12 and enters the diffuser portion 14, as shown in FIG. 1 (b), the one diffuser passage wall 15 formed by the crown plate 22 and the inner and outer peripheral covers 17 and 18, and the housing 11. Flows through the diffuser portion 14 without the guide vanes 19 having a passage width B with the other diffuser passage wall 16 formed by the width of b2, and as shown by a one-dot chain line in FIG. A higher pressure ratio can be obtained at the same flow rate than the broken line in FIG. 4 showing the case where the pressure is constant without changing, and the efficiency of the centrifugal compressor 10 on the high rotation high flow side can be improved.
[0044]
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.
[0045]
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.
[0046]
Therefore, in such a centrifugal compressor 10, in the performance curve shown in FIG. 4, the state of the solid line in the low rotation region where the guide vane 19 protrudes from the diffuser portion 14 and the passage width B is narrowed to b1, and the immersion The guide vanes 19 are taken in and out at the intersections where the same pressure ratio is obtained for the same flow rate at the same rotational speed in the state of the one-dot chain line in the high rotational range where the passage width B is widened to b2. By doing so, compared with the state of the broken line in which the passage width of the diffuser portion 14 is made constant, the usable range of the low rotation range is expanded, and the operation is always performed efficiently in a wide range from the low rotation range to the high rotation range. can do.
[0047]
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.
[0048]
In the above embodiment, the guide vanes are provided on the diffuser passage wall on the hub side, but may be provided on the diffuser passage wall on the shroud side if there is no space limitation.
[0049]
In the above-described embodiment, the centrifugal compressor applied to the vehicle supercharger has been described as an example. However, the present invention can be similarly applied to a centrifugal compressor that operates in another wide rotation range.
[0050]
【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 passage walls, A diffuser plate that can be inserted into and removed from an annular hole formed in one diffuser passage wall is provided, and a base end side surface of the guide vane is provided on the diffuser plate, while the other side of the guide vane protrudes from the other side when protruding to the other side. A diffuser that forms a part of the diffuser passage wall and closes the annular hole at the time of immersion to provide an annular crown plate that constitutes the one diffuser passage wall, and the guide vane protrudes and is immersed Since the passage width of the part is changed, the guide vanes are made into an annular diffuser plate and an annular crown plate. The guide vanes are moved in and out by moving the diffuser plate in an annular hole formed in the diffuser passage wall between them, and the shape of the sealing surface is made simple, and the diffuser plate and the crown plate are annular. Air gaps can be prevented by closing the gap, and the operating area is widened on the low flow rate side and efficiency is improved on the high flow rate side by changing the passage width of the diffuser section when the guide vanes protrude and immerse. It can be done independently or at the same time.
[0051]
This facilitates the processing of the holes necessary for inserting and removing the guide vanes, preventing air leakage and improving the efficiency of the centrifugal compressor.
[0052]
According to the centrifugal compressor according to claim 2 of the present invention, the guide vane is configured to protrude into the diffuser portion on the low rotation low flow side and to be immersed on the high rotation large flow side, and at the time of protrusion. Since the diffuser section has a narrower passage width than when immersed, it can be operated efficiently on the low-rotation, low-flow side and on the high-rotation, large-flow side, and the operating range can be expanded on the low-flow side. Improvements can be achieved, and conflicting requirements can be met.
[0053]
Furthermore, according to the centrifugal compressor according to claim 3 of the present invention, the passage width of the diffuser portion is changed depending on the distance between the diffuser plate and the crown plate and the shape of the crown plate. Even in this case, the passage width of the diffuser can be changed with a simple structure.
[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 crown plate and a guide blade portion according to an embodiment of the present invention, in which a part of the guide blade portion is cut away, and the upper half guide blade is protruded, and the lower half guide blade is immersed. It is the longitudinal cross-sectional view made into the made state.
FIGS. 3A and 3B are partial enlarged cross-sectional views of a diffuser portion according to another embodiment of the centrifugal compressor of the present invention, in which FIG. 3A shows a state in which the guide vanes protrude, and FIG. 3B shows that the guide vanes are immersed; Each state is shown.
FIG. 4 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. 5 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 Recessed part 12 Impeller 13 Scroll 14 Diffuser part 15 Diffuser passage wall 16 Diffuser passage wall 17 Outer peripheral cover plate 18 Inner peripheral cover plate 19 Guide blade 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 B Diffuser portion passage width b1 Narrow passage width b2 Wide passage width

Claims (3)

A centrifugal compressor provided with guide vanes that can be taken in and out from at least one of the opposing diffuser passage 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 passage wall is provided, and a base end side surface of the guide vane is provided on the diffuser plate, while the other side when projecting from the tip side surface of the guide vane And forming an annular crown plate that closes the annular hole and forms the one diffuser passage wall at the time of immersion, so that the guide vanes are projected and retracted. A centrifugal compressor characterized by changing the passage width of the diffuser section. The guide vanes are configured to protrude into the diffuser portion at the low rotation and low flow rate side and to be immersed at the high rotation and high flow rate side, and the passage width of the diffuser portion at the time of protrusion is narrower than that at the immersion time. The centrifugal compressor according to claim 1. The centrifugal compressor according to claim 1 or 2, wherein a passage width of the diffuser portion is changed depending on a distance between the diffuser plate and the crown plate and a shape of the crown plate.

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