Abstract:
A diffuser apparatus includes a diffuser communicating radially outwardly with an exit of an impellor. The apparatus includes a housing with a plate that is rotatable about a rotational axis and forms a hub side wall. A side surface of the plate has a vane having one circumferential end fixed to the plate; the other end is movable in the direction of the axis. The housing includes an inclination path with one end opened to the hub side wall to bendably guide the vane so that the other end of the vane moves in the circumferential direction upon rotation of the plate and moves in the direction of the axis to a projected position to project into the diffuser. An actuator rotates the plate to drive the vane between the projected position and a retracted position where the other end is retracted into the hub side wall.

Description:
This is a 371 national phase application of PCT/JP2010/053900 filed 9 Mar. 2010, the content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a diffuser apparatus provided in a centrifugal compressor, the centrifugal compressor having the diffuser device, and a turbo supercharger having the centrifugal compressor. 
     BACKGROUND ART 
     There is a known centrifugal compressor in which a guide vane movable between a position where it is projected into a diffuser passage and a position where it is housed in a housing chamber provided in a diffuser wall is provided in a diffuser portion (see Patent Document 1). In addition, there is Patent Document 2 as prior art reference in relation to the present invention. 
     Citation List 
     Patent Literature 
     Patent Document 1: JP-A-2001-329996 
     Patent Document 2: JP-A-2008-095678 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the centrifugal compressor of Patent Document 1, when the guide vane is housed in the housing chamber, a gap between the diffuser wall and the guide vane is produced. When foreign matters pass through the gap into the housing chamber and are accumulated between the guide vane and the diffuser wall, the guide vane is incapable of moving. In addition, in the centrifugal compressor, the housing chamber having substantially the same width as the height of the guide vane is required to be provided alongside of the diffuser portion. For this reason, the size of the centrifugal compressor is increased. 
     In view of the foregoing, an object of the present invention is to provide a diffuser apparatus, a centrifugal compressor, and a turbo supercharger, which can prevent the immovability of a vane due to foreign matters and are advantageous to downsizing. 
     Solution To Problem 
     A diffuser apparatus of the present invention is a diffuser apparatus which has a diffuser formed by a shroud side wall portion and a hub side wall portion opposite each other and provided as a passage space communicated with the exit side of an impellor radially outwardly of the impellor of a centrifugal compressor, the apparatus including a hollow disc-like rotational member, a housing member which houses the rotational member therein so as to be rotatable about a rotational axis of the impellor and forms either one wall portion of the shroud side wall portion or the hub side wall portion, and driving device for rotating the rotational member, in which the side surface of the rotational member on the diffuser side is provided with a plate-like vane member having one end in the circumferential direction fixed to the rotational member, the other end in the circumferential direction movable in the direction of the rotational axis, and flexibility, the housing member is provided with an inclination path which has one end opened to the portion which forms the one wall portion, and bendably guides the vane member so that the other end in the circumferential direction of the vane member is moved in the circumferential direction with the rotation of the rotational member and is moved in the direction of the rotational axis so as to be projected into the diffuser, and the driving device rotates the rotational member so that the vane member is driven between a projected position where the other end in the circumferential direction of the vane member is projected into the diffuser and a retracted position where the other end in the circumferential direction of the vane member is retracted into the one wall portion. 
     According to the diffuser apparatus of the present invention, the vane member is bent by the inclination path so as to be projected into the diffuser. For this reason, foreign matters are hard to be accumulated in the housing member or the portion between the inclination path and the vane member, and further, even when foreign matters are accumulated, they cannot inhibit the movement of the vane member. In addition, even when foreign matters are accumulated in the inclination path, they are removed by the vane member moved from the retracted position to the projected position. Therefore, the immovability of the vane due to the foreign matters is prevented. Further, in the diffuser apparatus of the present invention, when the vane member is housed in the housing member, it is extended in the circumferential direction by the inclination path. Consequently, as compared with when the vane member is moved only in the direction of the rotational axis and is housed, the space to be provided for housing the vane member can be smaller. Thus, it is possible to downsize the diffuser apparatus. 
     In one embodiment of the diffuser apparatus of the present invention, the shape of the vane member may be set so that the distance between the other end of the vane member and the one end of the inclination path in the retracted position is gradually increased from the inner circumference side toward the outer circumference side. In this case, the length in which the vane member is projected from the one wall portion when it is moved to the projected position can be the same on the outer circumference side and the inner circumference side. For this reason, the clearance between the other wall portion of the shroud side wall portion or the hub side wall portion and the other end of the vane member can be substantially the same on the outer circumference side and the inner circumference side. It is possible to increase an amount of gas which contacts on the vane member within gas passing through the diffuser. 
     In one embodiment of the diffuser apparatus of the present invention, the shape of the vane member may be set so that the length in which the vane member is projected from the one wall portion in the projected position is gradually increased from the inner circumference side toward the outer circumference side, and the inclination path may be provided in the housing member so that an inclination with respect to a plane orthogonal to the rotational axis is gradually decreased from the inner circumference side toward the outer circumference side. In this embodiment, a projection angle when the vane member is projected from the one wall portion into the diffuser can be gradually decreased from the inner circumference side toward the outer circumference side. For this reason, even when the vane member is more projective on the outer circumference side than on the inner circumference side, the other end of the vane member can be abutted onto the other wall portion of the shroud side wall portion or the hub side wall portion in the same manner on each of the inner circumference side and the outer circumference side. This enables the clearance between the other end of the vane member and the other wall portion to be substantially the same on the outer circumference side and the inner circumference side. Therefore, it is possible to increase an amount of gas which contacts on the vane member within gas passing through the diffuser. 
     A centrifugal compressor of the present invention has the diffuser apparatus mentioned above. In addition, a turbo supercharger of the present invention has the centrifugal compressor mentioned above, the centrifugal compressor being provided in the intake passage of an internal combustion engine. Each of the centrifugal compressor and the turbo supercharger of the present invention has the diffuser apparatus mentioned above. For this reason, as in the diffuser device, the immovability of the vane member due to foreign matters can be prevented. In addition, it is possible to downsize each of the centrifugal compressor and the turbo supercharger. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view showing the cross section of a centrifugal compressor provided with a diffuser apparatus according to a first embodiment of the present invention. 
         FIG. 2  is a view of a main part of a movable vane mechanism viewed from the direction of an axis. 
         FIG. 3  is a view showing the cross sections of a diffuser taken along line S 1 -S 1  of  FIG. 2 . 
         FIG. 4  is a view showing a variation of the diffuser apparatus according to the first embodiment. 
         FIG. 5  is a view showing the movable vane mechanism of the diffuser apparatus according to a second embodiment of the present invention viewed from the direction of the axis. 
         FIG. 6  is a view showing the cross sections of the movable vane mechanism taken along line S 2 -S 2  and line S 3 -S 3  of  FIG. 5  when a vane is in a retracted position. 
         FIG. 7  is a view showing the cross sections of the movable vane mechanism taken along line S 2 -S 2  and line S 3 -S 3  of  FIG. 5  when the vane is in a projected position. 
         FIG. 8  is a view showing the movable vane mechanism of the diffuser apparatus according to a third embodiment of the present invention viewed from the direction of the axis. 
         FIG. 9  is a view showing the cross sections of the movable vane mechanism taken along line S 4 -S 4  and line S 5 -S 5  of  FIG. 8  when the vane is in the retracted position. 
         FIG. 10  is a view showing the cross sections of the movable vane mechanism taken along line S 4 -S 4  and line S 5 -S 5  of  FIG. 8  when the vane is in the projected position. 
         FIG. 11  is a view showing a main part of a first variation of the diffuser apparatus of the present invention. 
         FIG. 12  is a view showing a main part of a second variation of the diffuser apparatus of the present invention. 
         FIG. 13  is a view showing a main part of a third variation of the diffuser apparatus of the present invention. 
         FIG. 14  is a view showing a main part of a fourth variation of the diffuser apparatus of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (First Embodiment) 
       FIG. 1  shows the cross section of a centrifugal compressor provided with a diffuser apparatus according to a first embodiment of the present invention. A centrifugal compressor  1  is incorporated into a turbo supercharger provided in an internal combustion engine in order to perform the supercharging of the internal combustion engine, and is provided in the intake passage of the internal combustion engine. As shown in this figure, the centrifugal compressor  1  includes a housing  2 , and an impellor  3  housed in the housing  2 . The housing  2  includes a wheel chamber  4  in which the impellor  3  is arranged, a diffuser  10  provided radially outwardly of the wheel chamber  4  and communicated with the exit of the wheel chamber  4 , and a scrolled scroll chamber  5  provided on the outer circumference of the diffuser  10  and communicated with the diffuser  10 . The impellor  3  is attached to a rotational shaft  6  rotatably provided about an axis Ax. In addition, the impellor  2  is fixed to the rotational shaft  6  by a nut  6   a . Further, the turbine wheel of a turbine provided in the exhaust passage of the internal combustion engine is attached to the other end of the rotational shaft  6 . 
     The diffuser apparatus will be described in detail with reference to  FIGS. 1 to 3 . As shown in  FIG. 1 , the diffuser  10  is formed by a shroud side wall portion  10   a  and a hub side wall portion  10   b  opposite each other. A movable vane mechanism  11  is provided in the hub side wall portion  10   b .  FIG. 2  is a view of the main part of the movable vane mechanism  11  viewed from the direction of the axis Ax. In addition,  FIG. 3  shows the cross sections of the diffuser  10  taken along line S 1 -S 1  of  FIG. 2 . As shown in these figures, the movable vane mechanism  11  includes a rotational plate  12  as a rotational member, a housing portion  13  as a housing member which houses the rotational plate  12  therein, and an actuator  14  as a driving device which rotates the rotational plate  12 . 
     The rotational plate  12  is hollow disc-like, and is housed in the housing portion  13  so as to be rotatable about the axis Ax. Plural (six in  FIG. 2 ) vanes  15  are provided in the rotational plate  12 . As shown in  FIG. 2 , the vanes  15  are arranged at intervals on the same circumference. Each of the vanes  15  is a thin plate member having flexibility. In the vane  15 , only one end  15   a  in the circumferential direction is connected to the rotational plate  12 , and the portion other than that is separated from the rotational plate  12 . 
     As shown in  FIG. 3 , the housing portion  13  includes a first plate  16 , and a second plate  17 . As shown in this figure, the first plate  16  is arranged on the diffuser  10  side so as to form the hub side wall portion  10   b . The first plate  16  and the second plate  17  are combined so that the rotational plate  12  is interposed therebetween. In this case, a space S is formed between the first plate  16  and the second plate  17 , and the rotational plate  12  is arranged in the space S. A hole (not shown) having substantially the same size as the outside diameter of the rotational plate  12  is provided in the portion of the second plate  17  forming the space S. In addition, a shaft (not shown) having substantially the same size as the inside diameter of the rotational plate  12  is provided in the center of the hole so as to be coaxial with the hole. The rotational plate  12  is arranged in the space S so as to be inserted into the shaft. Therefore, the rotational plate  12  is incapable of moving to the radial direction. 
     As shown in this figure, inclination paths  18  which communicate the space S and the diffuser  10  are provided in the housing portion  13 . The inclination paths  18  are provided so as to be equal in number to that of the vanes  15 . In addition, the inclination paths  18  are provided at intervals in the circumferential direction. The cross section shape of each of the inclination paths  18  is set to a size in which the vane  15  is slidably movable when the rotational plate  12  is rotated. One end  18   a  of the inclination path  18  is opened to a surface  16   a  of the first plate  16  on which the diffuser  10  is formed. As shown in this figure, the other end  15   b  of the vane  15  is arranged in the inclination path  18 . The inclination path  18  bends the vane  15  so that the other end  15   b  of the vane  15  is moved in the direction of the axis Ax while being moved in the circumferential direction when the rotational plate  12  is rotated. 
     The actuator  14  is connected to the rotational plate  12  via a driving rod  19 . A driving hole  12   a  is provided in the rotational plate  12 , and a driving pin  19   a  provided at the end of the driving rod  19  is inserted into the driving hole  12   a.    
     In the movable vane mechanism  11 , when the driving rod  19  is driven by the actuator  14  in the direction of an arrow A of  FIG. 2 , the rotational plate  12  is rotated in the direction of an arrow R. Then, this also makes the vane  15  to be rotated in the direction of the arrow R. In this case, as shown in the upper diagram of  FIG. 3 , the vane  15  is rotated while being bent by the inclination path  18  so that the other end  15   b  is projected from the first plate  16  into the diffuser  10 . The actuator  14  stops the rotational plate  12  when the other end  15   b  of the vane  15  reaches the shroud side wall portion  10   a . In addition, in the second plate  17 , each of first projections (not shown) onto which each of first positioning portions  12   b  of the rotational plate  12  is abutted when the rotational plate  12  is rotated to this position is projected into the space S. Further, the position of the vane  15  in this case corresponds to a projected position of the present invention. 
     On the other hand, when the driving rod  19  is driven by the actuator  14  in the direction of an arrow B of  FIG. 2 , the rotational plate  12  is rotated in the direction of an arrow L. This makes the vane  15  to be moved in the direction of the arrow L, so that as shown in the lower diagram of  FIG. 3 , the vane  15  is retracted into the first plate  16 . The actuator  14  stops the rotational plate  12  when the entire vane  15  is retracted into the first plate  16 . In the second plate  17 , each of second projections  20  onto which each of second positioning portions  12   c  of the rotational plate  12  is abutted when the rotational plate  12  is rotated to this position is projected into the space S. Further, the position of the vane  15  in this case corresponds to a retracted position of the present invention. 
     As described above, according to the diffuser apparatus of the first embodiment, the vane  15  is moved in the circumferential direction, and is bent by the inclination path  18  so as to be projected into the diffuser  10 . For this reason, foreign matters are hard to be accumulated in the space S or between the inclination path  18  and the vane  15 , and further, even when foreign matters are accumulated, they cannot inhibit the movement of the vane  15 . In addition, for instance, even when foreign matters are accumulated in the inclination path  18 , they are removed by the vane  15  when the vane  15  is moved from the retracted position to the projected position. Therefore, the immovability of the vane  15  due to the foreign matters is prevented. Further, as shown in  FIG. 3 , in the diffuser  10  of the first embodiment, the vane  15  is housed in the space S while being bent in the circumferential direction by the inclination path  18 . Consequently, as compared with when the vane  15  is moved only in the direction of the axis Ax and is housed, the space for housing the vane  15  can be smaller. Thus, it is possible to downsize the diffuser  10 . 
     The shape of the inclination path  18  is not limited to the shape shown in  FIG. 3 . For instance, as shown in  FIG. 4 , the portion of the second plate  17 , which forms the inclination path  18  may be provided until it reaches the diffuser  10 . In this case, the cross section shape of the inclination path  18  is the same to the one end  18   a . For this reason, the projection and retraction of the vane  15  can be smoothly performed. Further, in the example shown in this figure, the second projection  20  is provided to the first plate  16 . In this way, the second projection  20  may be provided to either of the first plate  16  and the second plate  17 . 
     (Second Embodiment) 
     Next, the diffuser apparatus according to a second embodiment will be described with reference to  FIGS. 5 to 7 . Further, in this embodiment, components in common with the first embodiment are denoted by the same reference numerals and the description will be omitted.  FIG. 5  is a view showing the movable vane mechanism  11  of this embodiment viewed from the direction of the axis Ax.  FIG. 6  shows the cross sections of the movable vane mechanism  11  taken along line S 2 -S 2  and line S 3 -S 3  of  FIG. 5  when the vane  15  is in the retracted position.  FIG. 7  shows the cross sections of the movable vane mechanism  11  taken along line S 2 -S 2  and line S 3 -S 3  of  FIG. 5  when the vane  15  is in the projected position. Further, in  FIGS. 6 and 7 , each of the upper diagrams shows the cross section taken along line S 2 -S 2 , and each of the lower diagrams shows the cross section taken along line S 3 -S 3 . 
     As shown in  FIG. 6 , in this embodiment, the shape of the vane  15  is set so that the distance between the other end  15   b  of the vane  15  in the retracted position and the one end  18   a  of the inclination path  18  is gradually increased from the inner circumference side toward the outer circumference side. For this reason, as shown in this figure, in the vane  15  in the retracted position, on the inner circumference side, the other end  15   b  is flush with the hub side wall portion  10   b , but on the outer circumference side, the other end  15   b  is drawn into the hub side wall portion  10   b . In addition, as shown in  FIG. 5 , in this embodiment, the respective vanes  15  are provided on the inner circumference of the rotational plate  12 . 
     According to this embodiment, the shape of the vane  15  is set so that the distance between the other end  15   b  of the vane  15  in the retracted position and the one end  18   a  of the inclination path  18  is gradually increased from the inner circumference side toward the outer circumference side. For this reason, as shown in  FIG. 7 , a length Lp in which the vane  15  is projected from the hub side wall portion  10   b  when it is moved to the projected position can be the same on the outer circumference side and the inner circumference side. This enables the clearance between the other end  15   b  of the vane  15  and the shroud side wall portion  10   a  to be substantially the same on the outer circumference side and the inner circumference side. For this reason, it is possible to increase an amount of gas which contacts on the vane  15  within gas passing through the diffuser  10 . 
     (Third Embodiment) 
     The diffuser apparatus according to a third embodiment will be described with reference to  FIGS. 8 to 10 . Further, in this embodiment, components in common with the above embodiments are denoted by the same reference numerals and the description will be omitted.  FIG. 8  is a view showing the movable vane mechanism  11  of this embodiment viewed from the direction of the axis Ax.  FIG. 9  shows the cross sections of the movable vane mechanism  11  taken along line S 4 -S 4  and line S 5 -S 5  of  FIG. 8  when the vane  15  is in the retracted position.  FIG. 10  shows the cross sections of the movable vane mechanism  11  taken along line S 4 -S 4  and line S 5 -S 5  of  FIG. 8  when the vane  15  is in the projected position. Further, in  FIGS. 9 and 10 , each of the upper diagrams shows the cross section taken along line S 4 -S 4 , and each of the lower diagrams shows the cross section taken along line S 5 -S 5 . 
     In this embodiment, an inclination θ of the inclination path  18  with respect to a plane orthogonal to the axis Ax (in  FIG. 9 , the wall surface of the hub side wall portion  10   b ) is gradually decreased from the inner circumference side toward the outer circumference side. For this reason, as shown in  FIG. 9 , an inclination θout of the inclination path  18  on the outer circumference side is smaller than an inclination θin of the inclination path  18  on the inner circumference side. In this case, as shown in  FIG. 10 , when the vane  15  is moved to the projected position, a projection angle θp 2  on the outer circumference side of the vane  15  is smaller than a projection angle θp 1  on the inner circumference side. 
     According to this embodiment, the inclination θ of the inclination path  18  with respect to the plane orthogonal to the axis Ax is gradually decreased from the inner circumference side toward the outer circumference side, so that a projection angle θp of the vane  15  is gradually decreased from the inner circumference side toward the outer circumference side. As shown in  FIG. 8 , the length in the circumferential direction of the vane  15  on the outer circumference side is longer than that on the inner circumference side, so that the length in which the vane  15  is projected from the hub side wall portion  10   b  on the outer circumference side is longer than that on the inner circumference side. In this embodiment, the projection angle θp is gradually decreased from the inner circumference side toward the outer circumference side, so that even when the vane  15  is more projective on the outer circumference side than on the inner circumference side, the other end  15   b  of the vane  15  can be abutted onto the shroud side wall portion  10   a  in the same manner on each of the inner circumference side and the outer circumference side. For this reason, the clearance between the other end  15   b  of the vane  15  and the shroud side wall portion  10   a  are substantially the same on the outer circumference side and the inner circumference side. Therefore, it is possible to increase an amount of gas which contacts on the vane  15  within gas passing through the diffuser  10 . 
     The present invention is not limited to the above embodiments, and may be embodied in various forms. For instance, in the above embodiments, the centrifugal compressor of the present invention is incorporated into the turbo supercharger, but the centrifugal compressor of the present invention may be used alone without being incorporated into the turbo supercharger. The diffuser apparatus of the present invention may be provided to the shroud side wall portion. 
     The mechanism for stopping the rotation of the rotational plate in the projected position or the retracted position is not limited to the mechanism of the above form. For instance, as shown in  FIG. 11 , a concave portion  30  which is concave radially inwardly is provided to the outer circumference of the rotational plate  12 . In addition, a convex portion  31  which is projected into the concave portion  30  is provided to the second plate  17 . Then, the width in the circumferential direction of at least either of the concave portion  30  and the convex portion  31  is appropriately set, so that the positioning in the rotation direction of the rotational plate  12  may be performed. In addition, as shown in  FIG. 12 , a convex portion  40  which is projected radially outwardly may be provided on the outer circumference of the rotational plate  12 , and a concave portion  41  in which the convex portion  40  is arranged may be provided to the second plate  17 . Also, in this case, the width in the circumferential direction of at least either of the convex portion  40  and the concave portion  41  is appropriately set, so that the positioning in the rotation direction of the rotational plate  12  may be performed. 
     The shape of each of the first plate  16  and the second plate  17  is not limited to the shape of the above embodiments. For instance, the first plate  16  and the second plate  17  may have the same thickness. In this case, as shown in  FIG. 13 , a step  50  is provided to the portion of the first plate  16  combined with the second plate  17 . Likewise, a step  51  which engages the step  50  of the first plate  16  is provided to the second plate  17 . Then, the second plate  17  may be positioned with respect to the first plate  16  by engaging the steps  50  and  51 . In addition, as shown in  FIG. 14 , a convex portion  60  is provided to the portion of the first plate  16  opposite the second plate  17 , and a concave portion  61  into which the convex portion  60  is fitted is provided to the second plate  17 . Then, the second plate  17  may be positioned with respect to the first plate  16  by fitting the convex portion  60  into the concave portion  61 .