JP6106944B2 - Centrifugal compressor and turbocharger - Google Patents

Description

  The present invention relates to a centrifugal compressor and a supercharger.

A supercharger that supplies pressurized air to supercharge an internal combustion engine, for example, rotates a turbine using the exhaust of the internal combustion engine, and rotates a compressor impeller directly connected to the turbine. Air is compressed and supplied to the intake side of the internal combustion engine. The impeller may be driven by a motor.
The centrifugal compressor used for such a turbocharger has a characteristic that when the amount of air flowing through the compressor decreases, the compressor characteristic curve exceeds the surge line and enters the surging region. . Therefore, an attempt has been proposed to apply the compressor in a wider range than the operating range of the internal combustion engine by moving the surge line in the compressor characteristic curve to the low flow rate side as much as possible.

  For example, Patent Document 1 proposes a structure for moving such a surging region to the small flow rate side. The centrifugal compressor of Patent Document 1 includes an impeller that is rotatably supported, and a shroud wall that extends upstream from the periphery of the impeller to form a suction port. An air circulation path is formed inside the shroud wall reaching the outer periphery of the vehicle. As a result, when the centrifugal compressor is operated, a part of the air sucked into the impeller is circulated through the air circulation passage, so that the flow capacity for generating surging is reduced.

JP 2009-257177 A

  By the way, in the centrifugal compressor as described in Patent Document 1, the shape of the air circulation passage is long (deep) in the direction from the suction port to the impeller in order to move the surging region to the small flow rate side, and the It is necessary to form a narrow width. However, due to such a shape, it is difficult to use a relatively inexpensive casting method because the core becomes too thin as a method of manufacturing the shroud wall for the air circulation passage portion, and relatively expensive cutting. A machining method such as machining must be employed.

  The present invention has been made in view of the above circumstances, and its object is to make it possible to manufacture the shroud wall structure that forms the air circulation passage by an inexpensive casting method, thereby reducing the manufacturing cost. An object of the present invention is to provide a centrifugal compressor and a supercharger that can be reduced.

The centrifugal compressor of the present invention is a centrifugal compressor having an impeller that is rotatably supported and a shroud wall that extends upstream from the periphery of the impeller and forms a suction port.
The shroud wall includes a first opening provided at a portion facing the impeller, and a second opening provided at an outer peripheral portion of the suction port upstream of the installation position of the impeller. An air circulation passage having a communication flow path for communicating the first opening and the second opening;
At least a part of the inner peripheral side wall portion of the communication channel in the shroud wall on the side of the communication channel is formed by an inner cylinder member.

  In the centrifugal compressor, the inner cylinder member forms a part of the inner peripheral side wall portion of the communication channel in the shroud wall on the side of the communication channel, and the inner peripheral side wall portion of the communication channel. It is preferable to be held in the remainder.

  Further, in the centrifugal compressor, an insert ring that forms a second opening of the air circulation passage by being attached to an outer peripheral portion of the suction port is attached to the suction port side of the shroud wall, The inner cylinder member preferably forms a part of the inner peripheral side wall portion of the communication channel in the shroud wall on the communication channel side and is held by the insert ring.

Further, in the centrifugal compressor, an insert ring that forms a second opening of the air circulation passage by being attached to an outer peripheral portion of the suction port is attached to the suction port side of the shroud wall, The inner cylinder member preferably forms the entire inner peripheral side wall portion of the communication flow path in the shroud wall and is held by the insert ring.
In the centrifugal compressor, the insert ring is preferably provided with fins disposed in the second opening and in the communication channel.

The supercharger of the present invention is a turbine section that converts flow energy of combustion gas discharged from an internal combustion engine into a rotational driving force, and is driven by the rotational driving force of the turbine section to compress gas and supply the compressed internal combustion engine to the internal combustion engine. A turbocharger comprising:
The compression unit includes the centrifugal compressor.

According to the centrifugal compressor of the present invention, since at least a part of the inner circumferential side wall portion of the communication flow path in the shroud wall is formed by the inner cylindrical member, when manufacturing the shroud wall, As for the portion forming the air circulation passage, in addition to the cavity corresponding to the air circulation passage, the portion into which the inner cylindrical member is incorporated can be formed in the cavity. Therefore, if these cavities are combined to form a relatively large cavity portion, Since the corresponding core can be made relatively thick, the casting method can be employed. Therefore, the part which forms the air circulation passage of the shroud wall can be manufactured by a relatively inexpensive casting method, thereby reducing the manufacturing cost.
Moreover, according to the supercharger of the present invention, the manufacturing cost can be reduced by providing the centrifugal compressor as the compression unit.

1 is a schematic configuration diagram of a first embodiment of a centrifugal compressor according to the present invention. It is principal part sectional drawing of 1st Embodiment of the centrifugal compressor which concerns on this invention. It is a perspective view which shows schematic structure of an inner cylinder member. It is a figure which shows an insert ring, Comprising: (a) is a front view, (b) is a side view. It is principal part sectional drawing which shows an example of the shroud wall manufactured by the casting method. It is a perspective view of the insert ring which hold | maintained the inner cylinder member integrally. It is principal part sectional drawing of 2nd Embodiment of the centrifugal compressor which concerns on this invention.

  Hereinafter, embodiments of the centrifugal compressor of the present invention will be described in detail with reference to the drawings. In the following drawings, the scale of each member is appropriately changed to make each member a recognizable size.

  FIG. 1 is a schematic configuration diagram of a first embodiment of a centrifugal compressor according to the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of the centrifugal compressor shown in FIG. It is a compressor. The centrifugal compressor 10 rotatably supports an impeller 12 in a housing 11, and the air sucked from the suction port 13 by the rotation of the impeller 12 is compressed along the shroud wall 14 by centrifugal force. Lead to 16. Then, the intake air is compressed by being guided to the compression flow path 16 in this way, and the compressed air is supplied to the manifold of the internal combustion engine.

  The impeller 12 has a hub portion 18 and a shroud portion 19 that are fixed to the rotary shaft 17 with nuts or the like. The shroud portion 19 is formed by a plurality of blades 12 a provided on the outer periphery of the hub portion 18. The shroud wall 14 facing the shroud portion 19 extends from the periphery of the impeller 12 to the upstream side to form the suction port 13.

  Further, as shown in FIG. 2, the shroud wall 14 is formed with a first opening 21 at a portion facing the blade 12a of the impeller 12, and further, an upstream suction port deviated from the installation position of the impeller 12. A second opening 22 is formed in the outer periphery of 13. Furthermore, an annular communication channel 23 that connects the first opening 21 and the second opening 22 is formed inside the shroud wall 14. Under such a configuration, the shroud wall 14 is formed with an air circulation passage 20 having a first opening 21, a communication channel 23, and a second opening 22.

  The first opening 21 is formed by cutting the entire housing 11 by lathe machining after casting the housing 11 as described later and then toward the communication channel 23 formed in advance at the time of casting. is there. That is, the first opening 21 is formed by turning the inner peripheral side wall 24 of the communication channel 23 in the shroud wall 14 by lathe machining, and the inner side of the inner peripheral side wall 24 (the impeller 12 is accommodated). It is formed so as to communicate from the arranged side) to the inside of the communication channel 23.

  Since the first opening 21 is thus formed over the entire circumference, the inner peripheral side wall 24 of the communication channel 23 is separated from the shroud wall 14 by the first opening 21. Therefore, in the present embodiment, a plurality of ribs 25 are formed on the first opening 21 side in the communication flow path 23, and the inner peripheral side wall portion 24 is connected and fixed to the shroud wall 14 by these ribs 25. Therefore, the inner peripheral side wall 24 of the shroud wall 14 does not fall off the shroud wall 14 with the processing of the first opening 21.

  However, in the present embodiment, the inner peripheral side wall portion 24 of the shroud wall 14 is partly formed on the side of the communication flow path 23 by the cylindrical inner cylinder member 26. As shown in FIG. 3, the inner cylinder member 26 has a plurality of cutouts 27 that are engaged with the ribs 25 on one side, and the cutouts 27 are engaged with the ribs 25 to interfere with the ribs 25. Without being accommodated and retained in the remaining part 24a of the inner peripheral side wall part 24. In this embodiment based on such a configuration, the inner peripheral side wall portion 24 is formed by the inner cylinder member 26 disposed on the communication flow path 23 side and the remaining portion 24 that holds the inner peripheral surface thereof. Yes.

  The inner cylinder member 26 is housed and retained in the remaining portion 24 a of the inner peripheral side wall portion 24 connected to the shroud wall 14 by the rib 25, so that the inner cylinder member 26 is integrally assembled to the shroud wall 14. In the present embodiment, as shown in FIG. 2, a stepped portion 28 is formed on the other side (the side opposite to the notch 27) of the inner cylindrical member 26, and this stepped portion 28 is the remaining portion of the inner peripheral side wall portion 24. Positioning is performed by engaging a stepped portion (not shown) formed in 24a. In addition, the inner cylinder member 26 is fixed to the remaining portion 24a by press-fitting the larger diameter side of the step portion 28 of the inner cylinder member 26 into the smaller diameter portion of the step portion of the remaining portion 24a.

  The second opening 22 is formed by attaching an insert ring 30 to a recess 29 continuous with the communication channel 23. The recess 29 is formed in advance when the housing 11 is cast, and is formed at a position corresponding to the suction port 13. The insert ring 30 is fixed to the shroud wall 14 with bolts 31, and as shown in FIGS. 4 (a) and 4 (b), the ring body 32 and a plurality of fins 33 provided on the tip side thereof are integrated. It is formed.

  The ring main body 32 has a substantially cylindrical shape, and has a mounting portion 32a extending in an annular shape on the rear end side as shown in FIG. And the ring main body 32 (insert ring 30) is fixed to the shroud wall 14 by the volt | bolt 31 being inserted in the volt | bolt hole 32b formed in this attaching part 32a. At this time, the ring main body 32 is arranged with a predetermined interval with respect to the inner peripheral side wall portion 24. The gap formed between the inner peripheral side wall portion 24 and the ring main body 32 is the second opening 22 shown in FIG. Further, the inside of the ring main body 32 becomes the suction port 13 of the shroud wall 14.

  As shown in FIGS. 2, 4 (a) and 4 (b), the fins 33 are the first fins 33 a disposed in the second opening 22 and the second fins disposed in the communication channel 23. 33b. The first fin 33a and the second fin 33b are formed to be inclined at a predetermined angle with respect to the radial direction of the ring main body 32 as shown in FIG. With such a configuration, the fin 33 rectifies the air flowing through the communication flow path 23 and the second opening portion 22 shown in FIG.

  Here, the rectification for turning the air into the swirling flow is mainly performed by the first fins 33 a disposed in the second opening 22. Therefore, it is preferable to make the length of the first fin 33a along the air flow, that is, the length of the second opening 22 corresponding to the length as long as possible. Therefore, as described above, the shape of the air circulation passage 20 is made narrower, thereby increasing the thickness of the inner peripheral side wall portion 24 and increasing the length of the second opening portion 22. .

  However, when the width of the air circulation passage 20, that is, the width of the communication flow path 23 is reduced in this way, when the shroud wall 14 having such a communication flow path 23 is manufactured by a casting method, The corresponding core becomes too thin, making it difficult to manufacture. Therefore, conventionally, the communication channel 23 is relatively wide and manufactured by a casting method, or is processed by a machining method such as cutting.

  On the other hand, in the centrifugal compressor 10 of the present embodiment, the inner peripheral side wall portion 24 is formed by the inner cylindrical member 26 and the remaining portion 24a. The communication channel 23 having a narrow width can be formed by forming a width corresponding to the width of the inner cylinder member 26 and then incorporating the inner cylinder member 26.

  That is, in order to manufacture the shroud wall 14 having such a communication channel 23, the shroud wall 14 is formed into a shape as shown in FIG. For the communication channel, a width (cavity) corresponding to the inner cylinder member 26 is added to the width (cavity) of the communication channel 23 shown in FIG. Cavity) is formed. Therefore, in order to correspond to this communication flow path part 34 (cavity part), a relatively thick core can be used.

  Note that the ribs 25 are also formed during the casting production. Further, the inner peripheral side wall portion 35 is formed to be sufficiently thick, and the remaining portion 24a of the inner peripheral side wall portion 24 having the shape shown in FIG. 2 as shown by a broken line in FIG. 5 is obtained by subsequent cutting (machining). To form. Further, a step portion (not shown) of the remaining portion 24a and the first opening 21 are also formed.

  Next, the separately prepared inner cylinder member 26 is fitted into the formed communication flow path 34, and the notch 27 is engaged with the rib 25. Further, the large diameter side of the step portion 28 of the inner cylinder member 26 is press-fitted into the small diameter portion of the step portion of the remaining portion 24a, thereby fixing the inner cylinder member 26 in the remaining portion 24a. If the inner cylinder member 26 is once incorporated in the communication flow path 34 and becomes a part of the inner peripheral side wall 24 of the communication flow path 23, it is not necessary to remove it thereafter. Therefore, the inner cylinder member 26 can be fixed to the shroud wall 14 by press-fitting without being configured to be detachable.

  After that, as shown in FIG. 2, the insert ring 30 is attached to the recess 29 continuous with the communication flow path 23, and is further fixed to the shroud wall 14 with bolts 31. Thus, the second opening 22 is formed to form the air circulation flow path 20 including the first opening 21, the communication flow path 23, and the second opening 22, and the suction port 13 is formed.

The centrifugal compressor 10 thus formed rotates the impeller 12 with the rotation of the rotating shaft 17 directly connected to a turbine (not shown), and sucks air from the suction port 13.
The sucked air is compressed through the shroud portion 19 by the blades 12a, guided to the compression flow path 16, and supplied to the intake pipe side of the engine. Further, during low flow rate operation, the pressure in all regions of the impeller 12 is higher than the pressure in the air circulation passage 20, and a part of the air passing through the blade 12a is in the air circulation flow path 20, that is, the first flow. The air flow A passes through the communication channel 23 and the second opening 22 from the opening 21.

  On the other hand, the air B entering from the suction port 13 merges with the air flow A to become an air flow that flows in the direction of the first opening 21. Therefore, a circulation flow indicated by an arrow A is generated in the air circulation passage 20. With this circulation flow A, it is possible not to enter the surging region even in an operation state with a low flow rate capacity that enters the surging region of the compressor.

  In the centrifugal compressor 10 of the present embodiment, a part of the inner peripheral side wall portion 24 of the communication channel 23 in the shroud wall 14 on the side of the communication channel 23 is formed by the inner cylinder member 26. When the shroud wall 14 is manufactured, the part where the air circulation passage 20 (communication flow path 23) is formed may be formed as a cavity in addition to the cavity corresponding to the communication flow path 23. it can. Therefore, since these cavities may be combined to form a relatively large cavity (communication flow path portion 34), the corresponding core can be made relatively thick, and therefore the casting method can be adopted without difficulty. . Therefore, since the site | part which forms the air circulation path 20 of the shroud wall 14 can be manufactured with a comparatively cheap casting method, reduction of manufacturing cost can be aimed at.

Further, since the inner cylindrical member 26 is held and fixed to the remaining portion 24a of the inner peripheral side wall portion 24 of the communication flow path 23 by press fitting, the formation of the communication flow path 23 becomes extremely easy, and therefore the manufacturing cost is reduced. Reduction can be achieved.
Moreover, since the fin 33 arrange | positioned in the 2nd opening part 22 and the communication flow path 23 is provided in the insert ring 30, the air which flows through the air circulation flow path 20 is swirled in a desired direction by the fin 33. The flow can be rectified so as to be a swirling flow.

  In the embodiment, the insert ring 30 is formed by integrally forming the ring body 32 and the fins 33. However, in the embodiment, the insert ring 30 is inserted only by the ring body 32 without the fins 33. The ring 30 may be formed.

Further, when the insert ring 30 in which the ring main body 32 and the fins 33 are integrally formed as in the above embodiment is used, the inner cylinder member 26 is held integrally with the insert ring 30 as shown in FIG. May be.
In FIG. 6, the inner cylinder member 26 is fitted on the tip edge 36a of the first fin 33a and between the inner peripheral edges 36b of the second fin 33b of the plurality of fins 33 formed in a substantially L shape, and is integrated therewith. Is held. Or the inner cylinder member 26 and the insert ring 30 may be produced as a single component integrated in advance.

  If comprised in this way, the inner cylinder member 26 and the insert ring 30 can be handled as a single part, Therefore, the number of parts of the centrifugal compressor 10 can be apparently reduced or actually reduced. Further, since the inner cylinder member 26 is integrally held by the insert ring 30, it is necessary to form the step portion 28 in the inner cylinder member 26 to position and press-fit the inner cylinder member 26 as in the first embodiment. Therefore, the processing of the inner cylinder member 26 and the steps required for this press-fitting can be omitted. Therefore, the manufacturing cost can be reduced.

  FIG. 7 is an enlarged cross-sectional view of a main part of a second embodiment of the centrifugal compressor according to the present invention. The centrifugal compressor 40 shown in FIG. 7 is different from the centrifugal compressor 10 shown in FIG. 2 in that the centrifugal compressor 10 shown in FIG. 2 has an inner peripheral side wall portion of the communication channel 23 in the shroud wall 14. 7 is formed by the inner cylinder member 26, whereas in the centrifugal compressor 40 shown in FIG. 7, the entire inner peripheral side wall portion of the communication channel 23 in the shroud wall 41 is formed by the inner cylinder member 42. This is the point.

  That is, in this embodiment, as shown in FIG. 7, the entire inner peripheral side wall portion of the communication flow path 23 is formed by the inner cylinder member 42, and the inner cylinder member 42 is further formed as in the example shown in FIG. It is held by the insert ring 30. By configuring in this way, the inner peripheral side wall portion 24 formed of the inner cylinder member 42 is held and fixed to the shroud wall 41 through the insert ring 30, unlike the first embodiment.

  Therefore, the rib 25 is formed on the first opening 21 side of the communication flow path 23 in the first embodiment, whereas the formation of the rib 25 can be omitted in the present embodiment. In addition, since the rib 25 is not formed, the formation of the notch (27) that engages with the rib 25 can be omitted also for the inner cylinder member 42.

  Manufacturing the shroud wall 41 of the centrifugal compressor 40 having such a configuration can be more easily performed by a casting method. That is, not only the communication flow path portion 34 but also the arrow side indicated by the line CC in FIG. 5 can be further formed as a hollow portion at a location corresponding to the inner peripheral side wall portion shown in FIG. At this time, the formation of the ribs 25 can also be omitted. Therefore, the shape of the core can be simplified and can be made larger than in the case of the first embodiment. Or a core can be made unnecessary.

  After casting in this way, the insert ring 30 that holds the separately prepared inner cylinder member 42 is attached to the formed cavity, and is fixed to the shroud wall 41 with bolts 31. At that time, the inner cylinder member 42 is arranged so that the front end surface thereof is separated from the shroud wall 41 with a predetermined gap. Thereby, the first opening 21 can be formed between the shroud wall 41 and the distal end surface of the inner cylinder member 42. Therefore, by attaching the insert ring 30 that holds the inner cylinder member 42, the first opening 21, the communication channel 23, and the second opening 22 are simultaneously formed, and the air circulation channel 20 is formed. A suction port 13 can also be formed.

  In the centrifugal compressor 40 of the present embodiment, the entire inner peripheral side wall portion of the communication flow path 23 in the shroud wall 41 is formed by the inner cylinder member 42, and the inner cylinder member 42 is held by the insert ring 30. Therefore, the formation of the rib 25 and the processing of the first opening 21 can be omitted. Moreover, since the shape of the core can be made simple and large, or the core can be made unnecessary, the manufacture of the shroud wall 41 by a casting method can be made easier. Therefore, the manufacturing cost can be further reduced.

  Note that the insert ring 30 that holds the inner cylinder member 42 may have a configuration in which the inner cylinder member 42 is held by the fins 33 of the insert ring 30 as in the example shown in FIG. The member 42 and the insert ring 30 may be fabricated as a single part integrated in advance.

As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the said embodiment, Of course, a various change can be made in the range which does not deviate from the main point of this invention.
For example, in the above-described embodiment, the inner cylinder member 26 (42) is held by the insert ring 30 and is held and fixed by being fitted to the fins 33. 26 (42) may be held and fixed to the ring body 32 by screwing or the like.

  Moreover, the centrifugal compressor of the said embodiment is applicable as a compression part of a supercharger. That is, generally, a turbocharger is connected to a turbine unit that converts flow energy of combustion gas discharged from an internal combustion engine into a rotational driving force, and is connected to the turbine unit via a rotating shaft, and the rotational driving force of the turbine unit is And a compression unit that is driven by the compressor to compress the gas and supply the compressed gas to the internal combustion engine. By providing the centrifugal compressor shown in the above embodiment as the compression unit in such a supercharger, this supercharger is also excellent in that the manufacturing cost is reduced.

  DESCRIPTION OF SYMBOLS 10 ... Centrifugal compressor, 11 ... Housing, 12 ... Impeller, 13 ... Inlet, 14 ... Shroud wall, 17 ... Rotating shaft, 19 ... Shroud part, 20 ... Air circulation path, 21 ... 1st opening part, 22 ... 2nd opening part, 23 ... Communication passage, 24 ... Inner peripheral side wall part, 24a ... Remaining part, 25 ... Rib, 26 ... Inner cylinder member, 30 ... Insert ring, 33 ... Fin, 34 ... Communication flow path part, 35 ... inner peripheral side wall part, 40 ... centrifugal compressor, 41 ... shroud wall, 42 ... inner cylinder member

Claims (7)

A centrifugal compressor having an impeller rotatably supported, and a shroud wall extending upstream from the periphery of the impeller to form a suction port,
The shroud wall includes a first opening provided at a portion facing the impeller, and a second opening provided at an outer peripheral portion of the suction port upstream of the installation position of the impeller. An air circulation passage having a communication channel for communicating the first opening and the second opening, and a rib provided on the first opening side of the communication channel,
A centrifugal compressor characterized in that at least a part of the inner peripheral side wall portion of the communication flow path in the shroud wall is formed by an inner cylinder member having a notch engaging with the rib. .   The inner cylinder member forms a part of the inner peripheral side wall portion of the communication channel in the shroud wall on the communication channel side and is held by the remaining portion of the inner peripheral side wall portion of the communication channel. The centrifugal compressor according to claim 1.   The insert ring which forms the 2nd opening part of the said air circulation path by being attached to the outer peripheral part of this inlet port is attached to the said inlet side of the said shroud wall, The 1st aspect is characterized by the above-mentioned. Or the centrifugal compressor of 2. An insert ring is attached to the inlet side of the shroud wall to form a second opening of the air circulation passage by being attached to the outer periphery of the inlet.
2. The centrifugal compressor according to claim 1, wherein the inner cylinder member forms an entire inner peripheral side wall portion of the communication channel in the shroud wall.   The centrifugal compressor according to claim 3, wherein the insert ring is provided with fins arranged in the second opening and in the communication channel. The centrifugal compressor according to claim 5, wherein the inner cylinder member is fitted to the fin. A turbocharger comprising: a turbine portion that converts flow energy of combustion gas discharged from an internal combustion engine into a rotational driving force; and a compression portion that is driven by the rotational driving force of the turbine portion to compress gas and supply the compressed internal gas to the internal combustion engine Machine,
A turbocharger comprising the centrifugal compressor according to any one of claims 1 to 6 as the compression unit.

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