JP6413858B2 - Impeller trim ratio variable mechanism of centrifugal compressor - Google Patents

Description

  The present invention relates to an impeller trim ratio variable mechanism suitable for being applied to a centrifugal compressor constituting a supercharger that increases the pressure of air taken in by an engine.

  In a centrifugal compressor used in a supercharger (turbocharger), when the amount of air decreases, its characteristic curve exceeds the surge line and enters the surging region. If the surge wire can be moved to the low flow rate side, surging can be prevented over a wider range than the engine operating range. As a technique for moving the surge wire to the low flow rate side, that is, a technique for preventing surging, there are those described in Patent Documents 1 to 3 below.

  The prior art described in Patent Document 1 is configured as follows. An air chamber is provided in the shroud portion, and a guide vane is disposed in the air chamber so that air circulates through this portion. In addition, an air flow swirling mechanism is disposed in the upstream flow path so that the air flowing in this portion is swung in the same direction as the impeller.

  The prior art described in Patent Document 2 is configured as follows. An on-off valve is disposed in an intake pipe connected to the compressor housing, and this on-off valve is controlled so that the front and rear pressures at the outlet and the inlet of the compressor are kept the same.

  The prior art described in Patent Document 3 is configured as follows. A deformable vane is disposed in the suction flow channel upstream of the impeller so that the air flowing through this portion swirls. The deformable vane is intended to deform the vane to generate the desired positive or negative pre-swirl flow.

JP 2005-23792 A JP-A-61-164038 JP 2004-162716 A

  The above prior art has the following problems. Circulating the air immediately before the impeller to suppress the generation of vortices or to make the air in the suction flow path upstream of the impeller swirl has a certain effect in preventing surging, but surging Whether or not it occurs depends largely on the trim ratio of the compressor impeller (square of inlet diameter / square of outlet diameter). That is, the operating range of the compressor cannot be changed greatly without changing the shape of the impeller.

  The present invention has been made in view of the above circumstances, and its purpose is a mechanism that can achieve the same (near) anti-surging effect as when the impeller trim ratio is changed without changing the shape of the impeller. Is to provide.

  The present invention is an impeller trim ratio variable mechanism of a centrifugal compressor and has the following configuration. A plurality of aperture plates having an arm portion disposed around the tip of the impeller, a movement guide portion of the arm portion, an engagement portion that engages with the arm portion, and rotating to move the movement guide portion; And a drive ring that moves the throttle plate inward and outward of the intake passage by moving the arm portion along the intake section.

  According to the present invention, it is possible to create a state close to a state where the inlet diameter of the impeller is small by disposing a plurality of throttle plates at the tip of the impeller and projecting the plurality of throttle plates inward of the intake passage. . As a result, it is possible to obtain the same (near) anti-surging effect as when the impeller trim ratio is changed.

It is an exploded view of the impeller trim ratio variable mechanism which concerns on one Embodiment of this invention. FIG. 3 is a side sectional view of the compressor when the impeller trim ratio variable mechanism shown in FIG. 1 is disposed in the compressor of the turbocharger. FIG. 2 is a partial front cross-sectional view of the compressor when the impeller trim ratio variable mechanism shown in FIG. 1 is disposed in the compressor of the turbocharger. It is the schematic for demonstrating the structure of a turbocharger.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the structure of the turbocharger 100 (supercharger) will be described with reference to FIG. In a turbocharger 100 that supercharges an engine, a turbine 21 (turbine wheel) and an impeller 22 (compressor wheel) are integrated with each other via a turbine shaft 23. The turbine 21 is accommodated in the turbine housing 24, and the impeller 22 is accommodated in the compressor housing 25. The turbine 21 is rotated by exhaust from the engine, and the impeller 22 is rotated by the power. Air compressed by the rotation of the impeller 22 is supplied to the engine.

(Structure of variable impeller trim ratio)
FIGS. 1 to 3 are views for explaining an impeller trim ratio variable mechanism according to an embodiment of the present invention. The impeller trim ratio variable mechanism of the present invention is applied to a compressor (centrifugal compressor) of a turbocharger 100. FIG. This is an example of the case. Note that the impeller trim ratio variable mechanism of the present invention can be applied not only to a centrifugal compressor constituting a supercharger (turbocharger) but also to a centrifugal compressor used as an air source facility or the like. be able to.

  As shown in FIG. 1, the impeller trim ratio variable mechanism includes a plurality of diaphragm plates 3 to which pins 2 as arm portions are attached, an annular drive ring 4 that is a driving means for the diaphragm plate 3, The diaphragm plate 3 and the drive ring 4 are provided so as to sandwich the diaphragm plate 3 and the drive ring 4.

  The diaphragm plate 3 is a fan-shaped diaphragm plate body 1 having pins 2 attached thereto, and the pins 2 are projected from both surfaces of the diaphragm plate body 1. As shown in FIG. 2, the inner peripheral surface 1 a of the diaphragm plate body 1 is a tapered surface that inclines inward of the intake passage 26 toward the impeller 22 side. As shown in FIG. 3B, in the state where the throttle plates 3 have advanced from the annular hole 25a (see FIG. 2) provided in the compressor housing 25 to the inside of the intake passage 26, the plurality of throttle plates 3 are As a whole, they come into contact with each other to form a ring-shaped plate with no gap. In other words, each diaphragm plate body 1 is, for example, a ring-shaped plate divided into a plurality of fans, and is divided into six equal parts in this embodiment. As shown in FIG. 2, the diaphragm plate 3 (the diaphragm plate body 1) is disposed around the tip of the impeller 22, in other words, immediately upstream (closest) to the impeller 22.

  It should be noted that instead of the throttle plate body 1 in which the side surfaces are in contact with each other when the plurality of throttle plates 3 are advanced toward the inside of the intake passage 26, the front and back surfaces of the throttle plate main body when they are advanced toward the inside of the intake passage 26. It is also preferable to use a diaphragm plate body having a shape and size in which a part of the apertures overlap. This is because it is easy to form a ring shape with no gap when viewed in the air flow direction.

  The drive ring 4 includes an annular drive ring body 8 and a plurality of engaging portions 9 extending from the drive ring body 8 to the center of the ring. The engaging portion 9 has a U-shaped groove portion 9 a into which the pin 2 of the diaphragm plate 3 is fitted. The plurality of engaging portions 9 are arranged at predetermined intervals in the circumferential direction of the drive ring main body 8, and are arranged at equal intervals in this embodiment. The drive ring 4 is rotationally driven by a motor (not shown) via a link mechanism (not shown), a gear mechanism (not shown), etc., for example.

  The first ring plate 5 is formed with a plurality of slit holes 5a extending obliquely with respect to the circumferential direction. The same applies to the second ring plate 6, and a plurality of slit holes 6 a extending obliquely with respect to the circumferential direction are formed in the second ring plate 6. The slit holes 5 a and 6 a are portions into which the pin 2 of the diaphragm plate 3 is fitted, and are elongated holes that play a role of guiding the movement of the pin 2. These ring plates 5 and 6 are fixed to the compressor housing 25 or the like in a direction parallel to the drive ring 4. A spacer 7 is disposed between the first ring plate 5 and the second ring plate 6 at a predetermined interval in the circumferential direction of these plates. The distance between the first ring plate 5 and the second ring plate 6 is determined by the spacer 7 so that the movement of the diaphragm plate 3 and the rotation of the drive ring 4 are smoothly performed. It is made slightly larger than the dimension obtained by adding the thickness.

(Operation of variable impeller trim ratio mechanism)
The operation of the above-described impeller trim ratio variable mechanism will be described. The retracted state of the throttle plate 3 shown in FIG. 2 (a) and FIG. 3 (a) is when the amount of air flowing through the intake passage 26 is large, and impeller trim ratio (square of inlet diameter / 2 of outlet diameter). (Power) is (D1a) ² / (D2) ² .

The amount of air flowing through the intake passage 26 is reduced, and from the retracted state of the diaphragm plate 3 shown in FIGS. 2 (a) and 3 (a), the state of advancement of the diaphragm plate 3 shown in FIGS. 2 (b) and 3 (b). When switching to, the drive ring 4 is rotated by a predetermined angle by a signal from an ECU (not shown). Then, the pin 2 of the diaphragm plate 3 inserted in the slit holes 5a and 6a of the ring plates 5 and 6 is moved along the slit holes 5a and 6a by being pushed by the engaging portion 9 of the drive ring 4, Thereby, the diaphragm plate body 1 to which the pin 2 is fixed advances obliquely toward the inside of the intake passage 26. The state where the diaphragm plate main body 1 has advanced is the state shown in FIGS. 2 (b) and 3 (b). The intake passage 26 immediately upstream (immediately) of the impeller 22 is throttled by the plurality of throttle plates 3, and the inner diameter thereof is D1b (<D1a). As a result, an effect similar to an impeller having an impeller trim ratio of (D1b) ² / (D2) ² having a different shape can be obtained, and the surging area of the compressor constituting the turbocharger 100 moves to the low flow rate side. Surging is suppressed.

When the amount of air flowing through the intake passage 26 increases, the drive ring 4 is rotated in the reverse direction to return to the original position (phase). Then, as shown in FIGS. 2A and 3A, the diaphragm plate 3 (the diaphragm plate body 1) is stored in the wall of the compressor housing 25. Since the impeller trim ratio is (D1a) ² / (D2) ² , the surging area and choke area of the compressor move to the large flow rate side.

(Action / Effect)
In the impeller trim ratio variable mechanism configured as described above, a plurality of throttle plates 3 arranged around the tip of the impeller 22 are protruded inward of the intake passage 26 to create a state where the inlet diameter of the impeller 22 is small. Can do. As a result, it is possible to obtain the same (near) anti-surging effect as when the trim ratio of the impeller 22 is changed, and it is possible to suppress surging even when the amount of air flowing through the intake passage 26 is small. Further, when the amount of air flowing through the intake passage 26 increases, the choke region returns to the large flow rate side by returning the inlet diameter of the impeller 22 to the original state. That is, the operating range of the compressor is expanded.

  In the embodiment described above, the pair of ring plates 5 and 6 are fixedly disposed on the compressor housing 25 or the like so as to sandwich the plurality of diaphragm plates 3 and the drive ring 4. According to this configuration, the movement of the throttle plate 3 inward and outward of the intake passage 26 can be made more reliable with a simple configuration.

Further, in the above-described embodiment, the plurality of throttle plates 3 have a ring shape as a whole when viewed from the upstream side of the intake passage 26 in a state where they are advanced inward of the intake passage 26, and are outside the intake passage 26. In a state where the impeller 22 is retracted, the compressor housing 25 is housed in a wall that houses the impeller 22. According to this configuration, when the flow rate is low, a compressor characteristic equivalent to that of a smaller impeller trim ratio can be obtained more reliably, and when the flow rate is high, the impeller trim ratio (D1a) ² / (D2) ² is used. Compressor characteristics can be obtained reliably.

(Modification)
The above embodiment can be modified as follows.
The diaphragm plate 3 and the drive ring 4 may not be sandwiched between the pair of ring plates 5 and 6, but only one of the ring plates 5 and 6 may be used. In this case, the diaphragm plate 3 can be moved with a simpler configuration.

  In addition, a long and narrow groove (in place of the above-described slit holes 5a and 6a) serving as a movement guide portion for the pin 2 of the diaphragm plate 3 may be formed in the compressor housing itself. In this case, the ring plates 5 and 6 are unnecessary.

  In the above-described embodiment, the engagement portion 9 of the drive ring 4 that engages with the pin 2 of the diaphragm plate 3 has a U-shape. Instead, the drive ring main body 8 moves to the center of the ring. It may be a simple bar-shaped engaging portion that extends. In this case, the pin 2 is pushed by two engaging portions adjacent in the circumferential direction of the drive ring body 8. By rotating the drive ring main body 8, the pin 2 is pushed by one engaging portion to move the diaphragm plate 3, and by rotating the drive ring main body 8 in the reverse direction, the pin 2 is pushed by the other adjacent engaging portion and stopped. Return plate 3 to its original position. In addition, the engaging part provided in a drive ring is not limited to a U-shape or a rod shape.

  In the embodiment described above, the components are arranged in the order of the first ring plate 5, the diaphragm plate 3, the drive ring 4, and the second ring plate 6 from the upstream side of the air flow. Is not limited to this.

Further, the amount of expansion of the throttle plate body 1 inward of the intake passage 26 is not limited to two types of 0% (state of FIG. 3 (a)) and 100% (state of FIG. 3 (b)). It may be an intermediate amount of advancement. This aspect is particularly suitable when the diaphragm plate body 1 has a diaphragm plate body having a shape and size in which a part of the front and back surfaces of the diaphragm plate body overlap each other in a state where the diaphragm plate body 1 has advanced inward of the intake passage 26.
In addition, it is needless to say that various modifications can be made within a range that can be assumed by those skilled in the art.

1: Diaphragm plate body 2: Pin (arm part)
3: Diaphragm plate 4: Drive ring 5: First ring plate 5a: Slit hole (moving guide part)
6: 2nd ring plate 6a: Slit hole (movement guide part)
7: Spacer 8: Drive ring body 9: Engaging portion 22: Impeller 25: Compressor housing 26: Intake passage

Claims (5)

A plurality of aperture plates having an arm portion disposed around the tip of the impeller;
A movement guide part of the arm part;
A drive that has an engaging portion that engages with the arm portion, and moves the throttle plate inward and outward of the intake passage by rotating and moving the arm portion along the moving guide portion. Ring,
Equipped with a,
The inner peripheral surface of the diaphragm plate, that is a tapered surface which is inclined so as to protrude inwardly of the intake passage toward the impeller side, of a centrifugal compressor impeller trimming ratio variable mechanism. In the impeller trim ratio variable mechanism according to claim 1,
An impeller trim ratio variable mechanism for a centrifugal compressor, further comprising a ring plate fixedly arranged in a direction parallel to the drive ring and formed with a slit hole as the moving guide portion into which the arm portion is fitted. In the impeller trim ratio variable mechanism according to claim 2,
An impeller trim ratio variable mechanism of a centrifugal compressor, wherein a pair of the ring plates are fixedly arranged so as to sandwich the plurality of diaphragm plates and the drive ring. In the impeller trim ratio variable mechanism according to any one of claims 1 to 3,
The plurality of throttle plates have a ring shape as a whole when viewed from the upstream side of the intake passage when they are advanced inward of the intake passage, and accommodate the impeller when they are retracted outward of the intake passage. The impeller trim ratio variable mechanism of the centrifugal compressor stored in the wall of the housing. In the impeller trim ratio variable mechanism according to any one of claims 1 to 4,
Each of the plurality of diaphragms is formed in a fan shape,
The plurality of throttle plates are ring-shaped without gaps when the side surfaces are in contact with each other in the most advanced state toward the inside of the intake passage, and are separated from each other in the state of retreating outward from the intake passage. The centrifugal compressor impeller trim ratio variable mechanism.

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