Vortex blower

Abstract

To realize a separate type partition shape that reduces noise and serves as a highly efficient flow path, in a vortex blower.SOLUTION: In a vortex blower in which a suction passage 14 and a discharge passage 17 are formed at an end part of an arc-shaped stationary flow path 12, a partition plate 50 that can be separated from a casing is provided between the stationary flow path 12 and an impeller. The partition plate 50 is sized to cover at least a part of the discharge passage 17, and an outer edge shape 53b of the end part of the partition plate 50 on the discharge passage 17 side is formed to have the same contour shape as an end face shape of a blade 32 on an opening part side. Further, the impeller to be used has a semicircular cross-sectional shape in a circumferential direction and is manufactured by integral molding of metal.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vortex blower.

Background Art

[0002] A vortex blower is characterized in that the pressure coefficient representing the work per outer diameter of a single impeller is higher than that of a centrifugal blower, and it has been widely used conventionally as a relatively small-capacity blower. There has been an increasing demand for miniaturization, weight reduction, higher pressure, and further lower noise of this vortex blower. In response to this, various proposals have been made regarding the shape of the partition wall that separates the suction passage and the discharge passage provided on the stationary flow path. As such a vortex blower, Patent Document 1 and Patent Document 2 are known.

[0003] FIG. 12 is a perspective view of a vortex blower 101 of Patent Document 1. The vortex blower 101 has an electric motor 104 attached to a pedestal 102, and the electric motor 104 is assembled to a casing 110. The casing 110 has a disk portion 112a to which the rotating shaft 105 of the electric motor 104 is rotatably attached, and a stationary flow path 112 which is a groove having a semi-circular cross-sectional shape integrally provided outside the disk portion 112a. An impeller 130 is attached to the rotating shaft 105 with a nut 106, and the impeller 130 is rotationally driven by the electric motor 104. The impeller 130 is formed having a disk portion 132 extending radially outward from the rotating shaft 105 and a shroud 131 provided outside the disk portion 132 in the radial direction, and the cross-sectional shape orthogonal to the circumferential direction of the shroud 131 is formed in a substantially semi-circular shape. A cylindrical portion 112c is formed at the outer edge portion of the casing 110, and a casing cover 139 is attached so as to fit with the cylindrical portion 112c, and the impeller 130 is covered by the casing 110 and the casing cover 139. The vortex blower 101 is provided with a partition plate 150 (see FIG. 13 described later) that partitions the space between the suction passage 114 provided on the stationary flow path 112 and the discharge passage in the rotational direction.

[0004] FIG. 13 is a front view of the casing 110 and the partition plate 150 of the vortex blower 101 in FIG. 12. Here, the positions of the blades of the impeller 130 are superimposed and shown. The outer edge shape of the partition plate 150 as viewed from the direction of the rotation axis line A1 has a sufficient size to cover both the discharge passage 117 side and the suction passage 114 and the discharge passage 117. The curved portion 112b of the casing 110 is a groove portion formed in the circumferential direction, and the length of the curved portion 112b is slightly less than one circumference. One end side in the circumferential direction of the curved portion 112b communicates with the suction passage 114, and the other end side communicates with the discharge passage 117. The air flowing into the curved portion 112b from the suction passage 114 swirls as shown by the dotted line 22 due to the rotation of the impeller 130 and flows toward the discharge passage 117 side in the circumferential direction as shown by the arrow 22a, and is discharged from the discharge passage 117 as it flows as shown by the arrow 22b. The blade 132 of the impeller has a curved blade shape that promotes the rotation of the air such as the dotted line 22.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The vortex blower of Patent Document 1 is provided with a partition plate 150 so as to cover (intersect) the range obtained by projecting both the suction passage 114 and the discharge passage 117 in the front side direction of the rotation axis A1. By providing this partition plate 150, backflow of air from the discharge passage 117 side is prevented. This is because if backflow occurs, sufficient pressure cannot be increased and the performance deteriorates. Patent Document 1 describes a partition shape integrated with a casing for the purpose of noise reduction, and the overhang on the discharge side of the partition is made small. For this reason, there was a risk that air would stagnate in the space between the discharge passage and the partition, resulting in a decrease in efficiency. According to verification by the inventor, it was found that the phenomenon of air stagnating in the space between the discharge passage and the partition occurred due to the provision of the partition, and the efficiency was decreased.

[0007] An object of the present invention is to provide a vortex blower having a separate partition plate that provides a flow path with good efficiency while reducing noise. Another object of the present invention is to provide a vortex blower that realizes high efficiency and noise reduction by manufacturing an impeller by integrally forming it from metal and interposing a separate partition plate between the impeller and the casing.

Means for Solving the Problems

[0008] In order to solve the above problems, the vortex blower of the present invention is configured such that a separate partition plate is provided on a partition that separates a suction passage and a discharge passage. The casing has an annular groove centered on the rotation axis. The impeller is located in the annular groove and has a plurality of blades that partition in the circumferential direction across the annular groove. The vortex blower is provided with an arcuate stationary flow path centered on the rotation axis of the electric motor, and a casing in which a suction passage and a discharge passage are formed at the ends of the stationary flow path, and a plurality of blades provided at predetermined intervals in the circumferential direction corresponding to the stationary flow path and partitioning in the circumferential direction across the annular groove. The impeller is driven by an electric motor.

[0009] According to another feature of the present invention, a partition wall is formed at the end of the stationary flow path of the casing so as to partition the discharge passage and the suction passage in the rotational direction. Further, a partition plate that can be attached and detached by screws is provided between the partition wall of the casing and the impeller. The outer edge shape of the discharge passage side end of the partition plate is formed in the same contour shape as the end face shape of the blade close to the partition plate, and when viewed from the rotational axis direction of the impeller, the discharge passage and the partition plate overlap only a part on the side close to the circumferential suction passage and only a part in the radial direction.

[0010] According to still another feature of the present invention, the projection range of the discharge passage has a portion that overlaps when viewed from the partition plate and the rotational axis direction and a portion that does not overlap when viewed from the partition plate and the rotational axis direction. The discharge side end is located on an imaginary straight line connecting the rotational axis and the discharge passage. The impeller has a shroud provided with a curved portion and a plurality of blades formed so as to divide the continuously circumferential space formed by the curved portion, and the shroud and the blades are formed by an integral structure of metal. Further, there is no gap between the blades of the impeller and the inner wall surface of the shroud, and the air flow is blocked between adjacent spaces separated by the blades. The rotational axis of the electric motor is arranged coaxially with the rotational axis of the impeller.

Effects of the Invention

[0011] According to the present invention, an efficient vortex blower with reduced noise has been realized. Further, since the impeller is manufactured by integral formation of metal and a partition plate having an optimal shape is interposed between the openings of the discharge passage and the suction passage, the air flow near the opening of the discharge passage can be made smoother than before, and a vortex blower with high efficiency and reduced noise has been realized.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following figures, the front-rear, left-right, and up-down directions will be described as the directions indicated by the arrows in the figures. Also, in this embodiment, the same components are denoted by the same reference numerals, and repeated descriptions thereof will be omitted unless particularly necessary.

Example

[0014] FIG. 1 is an exploded perspective view of the vortex blower 1 of the present embodiment, showing a state in which the casing cover 40, the impeller 30 (see FIG. 4), and the partition plate 50 are removed from the casing 10. The basic configuration and shape of the vortex blower 1 are substantially the same as those of the conventional vortex blower 101 shown in FIG. 12. The casing 10 has an annular groove (stationary flow path 12) centered on the rotation axis A1, and the impeller 30 (see FIG. 4 described later) is arranged so as to face the stationary flow path 12 of the casing 10. The air taken in from the suction passage 14 by the rotation of the impeller 30 is allowed to flow between the casing 10 and the impeller 30, compressed sufficiently, and then discharged to the outside of the vortex blower 1 through the discharge passage 17.

[0015] The main differences between the vortex blower 1 of the present embodiment and the conventional vortex blower 101 shown in FIG. 12 are the shape of a part of the casing 10, the shape and structure of the impeller 30 (see FIG. 4), and the shape of the separable partition plate 50 (see FIG. 2). The vortex blower 1 uses the electric motor 4 as a power source to rotate the impeller 30 (see FIG. 4) attached to the rotation shaft 5 of the electric motor 4. The impeller 30 rotates within the space covered by the casing 10 and the casing cover 40, sucks air from the suction passage 14, and compresses the air while rotating and revolving in the circumferential direction within the stationary flow path 12, which is an annular groove formed between the impeller 30 and the casing 10.

[0016] The shape of the cross-section orthogonal to the circumferential direction of the stationary flow path 12 is the same as the shape shown in FIG. 12, and is hemispherical or substantially hemispherical. The stationary flow path 12 has a substantially annular shape when viewed from the front side as shown in FIG. 1, but is not a groove that is completely continuous in the circumferential direction, and the portion between the suction opening 15 and the discharge opening 18 is divided by the partition wall 20. The portion of the partition wall 20 is formed on the same plane as the flat disk portion 13 inside the stationary flow path 12. Three screw holes 29 for fixing the partition plate 50 are formed in the portion of the partition wall 20.

[0017] A suction opening 15 is formed on the right side of the partition wall 20. The suction opening 15 is a connecting portion that connects the inner wall of the cylindrical suction passage 14 and the inner wall of the stationary flow path 12 having a semicircular cross section, and the air flowing in from the suction passage 14 smoothly reaches the space surrounded by the stationary flow path 12 and the impeller 30 without staying. It is a portion formed such that the opening gradually widens from the rear side to the front side. The front edge portion of the suction opening 15 is connected to the stationary flow path 12. The discharge opening 18 is a connecting portion that connects the inner wall of the stationary flow path 12 having a semicircular cross section to the inner wall of the cylindrical discharge passage 17 and the inner wall of the stationary flow path 12 having a semicircular cross section, and the air discharged from the end of the stationary flow path 12 to the discharge passage 17 smoothly flows without staying. It is formed with a smooth curved surface. The discharge opening 18 is formed such that the opening gradually narrows from the connecting portion of the stationary flow path 12 toward the rear side and is connected to the discharge passage 17.

[0018] The suction passage 14 for the air sucked by the vortex blower 1 and the discharge passage 17 for discharging the air from the vortex blower 1 to the outside are arranged to extend parallel to the rotation shaft 5 of the electric motor 4, that is, in the front-rear direction. The suction opening 15 of the suction passage 14 and the discharge opening 18 of the discharge passage 17 are adjacent to the partition wall 20. A protrusion 16 having a substantially triangular shape when viewed from the front is formed on the suction passage 14 side from the partition wall 20, and a protrusion 19 having a substantially triangular shape when viewed from the front is formed on the discharge passage 17 side from the partition wall 20. The protrusion 16 and the protrusion 19 are formed integrally with the partition wall 20 and are formed of an aluminum alloy. The suction passage 14 and the discharge passage 17 (not visible in the figure) are provided from the casing 10 to the pedestal 2.

[0019] On the front side of the partition wall 20, a separate partition wall plate 50 is attached. The partition wall plate 50 is mounted so as to be located on the rear side of the impeller 30 (not visible in the figure as it is located inside the casing cover 40) attached to the rotating shaft 5, and is, for example, a metal plate such as an aluminum alloy. Here, three screws (not shown) are respectively passed through the screw holes 59a to 59c and screwed into the corresponding screw holes 29. A total of three screw holes 29 are provided, two on the upper side and one on the lower side. Incidentally, the screw holes 29 are provided for attaching the separate partition wall plate 50, so the position and number of the screw holes are arbitrary as long as the partition wall plate 50 can be stably fixed to the casing 10. Also, not only the fixing method using screws but also a combination of screws and stepped portions or other known fixing means such as unevenness may be used to fix the partition wall plate 50 to the casing 10.

[0020] The suction passage 14 extends in the front-rear direction substantially parallel to the rotating shaft 5, and a suction pipe (not shown) is connected to the rear end portion of the suction passage 14. Air is supplied to the suction passage 14 from the outside through the suction pipe (not shown). The discharge passage 17 extends in the front-rear direction substantially parallel to the suction passage 14, and a screw portion similar to that on the suction passage 14 side for connecting a discharge pipe (not shown) is provided near the rear end portion of the discharge passage 17.

[0021] FIG. 2 shows the partition plate 50 alone of 1, where (a) is a front view, (b) is a right side view, and (c) is a rear view. The function of the partition plate 50 is to prevent the pressure increase of the vortex blower from decreasing, and the impeller and the partition plate 50 are installed so as to be non-contact and maintain an appropriate gap. The circumferential length of the partition plate 50 is about the length of a plurality of blade numbers, here the length of the intervals of 5 blades of the blade 32, and the leakage flow rate from the discharge passage 17 to the suction passage 14 is reduced. Since the partition plate 50 is formed so as to cover the front side of the substantially annular stationary flow path 12 when viewed from the front, as shown in FIG. 2(a), the inner peripheral edge 51 and the outer peripheral edge 52 are formed in an arc shape. The partition plate 50 has a region extending to one side (the right side which becomes the suction passage 14 side) from the center of the region surrounded by the three screw holes 59a to 59c and a region extending to the other side (the left side which becomes the discharge flow path 17 side). The suction side end edge 54 on the stationary flow path 12 side of the partition plate 50 is formed in a straight line when viewed from the front. The discharge side end edges 53 (53a, 53b) on the discharge passage 17 side of the partition plate 50 are formed by a combination of two straight edges when viewed from the front, that is, the first edge 53a and the second edge 53b. Here, the virtual extension line shown by the two-dot chain line of the first edge 53a intersects the vertical center line B1 (a virtual vertical line passing through the rotation axis 5 when viewed in the left-right direction of the vortex blower 1) at the first angle θ1, that is, it is formed to be inclined with respect to the vertical center line B1. Similarly, the virtual extension line (not shown) of the second edge 53b is formed to be inclined with respect to the vertical center line B1 so as to intersect at the second angle.

[0022] As can be seen from the rear view of FIG. 2(c), in the region of the partition plate 50 on the intake passage 14 side, three inclined surfaces (56a, 56b, 56c) are formed to guide the sucked intake air in a predetermined direction within the stationary flow path 12. The main tapered surface 56a is a portion where the plate thickness t gradually thins from the back surface 50b portion having the plate thickness t. From a portion where it has thinned to a certain extent to the upper right portion, an upper tapered surface 56b is formed that gradually thins as it goes to the right and upward, and a lower tapered surface 56c is formed on the lower right portion that gradually thins as it goes to the right and downward. The boundary (ridge line portion) between the upper tapered surface 56b and the lower tapered surface 56c is not a perfect straight line, and the ridge line is arranged to be a gentle curve so that the air sucked from the intake passage 14 is guided to face in a predetermined direction within the stationary flow path 12. A tapered surface 53c with a gradually thinning plate thickness is also formed on the back side of the discharge side end edge 53 for rectification. A stepped portion 52a is formed on the back side of the outer peripheral edge 52.

[0023] A recess 57a is formed in the lower end portion of the lower tapered surface 56c, and an inclined surface is formed to guide the air near the recess 57a to the blade 32 side by the guide surface 57b. The notch portion 57c below the guide surface 57b is formed for rectification. As can be seen from FIG. 2(b), a front tapered surface 57d is formed in a portion of the surface 50a near the intake side end edge 54 such that the surface 50a side is shaved so that the thickness becomes thinner as it moves away from the center line B1.

[0024] FIG. 3 is a front view of the casing 10 of the vortex blower 1 and the partition plate 50. Here, the contour of the impeller 30 located on the front side (near side of the paper surface) of the partition plate 50 is also shown so as to overlap. In order to explain the positional relationship between the blades 32 of the impeller 30, the partition plate 50, the suction passage 14, and the discharge passage 17, the blades 32 are virtually shown by thin lines. The stationary flow path 12 has the suction passage 14 opening at one end side in the circumferential direction and the discharge passage 17 opening at the other end side. As can be seen from FIG. 1, between the opening of the cylindrical suction passage 14 and the stationary flow path 12, it is connected by a suction opening 15 formed by a gentle slope. The suction opening 15 is shown with a double contour, and the outer contour is the contour line obtained by projecting the connection point with the stationary flow path 12 to the front side in the direction of the rotation axis A1. Similarly, between the opening of the cylindrical discharge passage 17 and the stationary flow path 12, it is connected to a discharge opening 18 formed by a gentle slope. The discharge opening 18 is also shown with a double contour like the suction opening 15, and the outer contour is the contour line obtained by projecting the connection point with the stationary flow path 12 to the front side in the direction of the rotation axis A1. Between the respective openings 15 and 18, a partition wall 20 is provided which partitions the suction passage 14 and the discharge passage 17 sides and divides the circumferential groove of the stationary flow path 12.

[0025] As can be understood from FIG. 3, on the cross-section line A-A', the partition plate 50 covers the suction passage 14, while the partition plate 50 only partially covers the discharge passage 17. The cross-section line A-A' is a cylindrical surface centered on the rotation axis A1 and passing through the centers of the suction passage 14 and the discharge passage 17. The shape of the partition plate 50 shown in FIG. 3 is slightly different from the first edge portion 53a and the second edge portion 53b of the partition plate 50 shown in FIG. 2, and the first edge portion 53a and the second edge portion 53b are formed in a curved surface shape. Whether the shapes of the first edge portion 53a and the second edge portion 53b are formed by a combination of straight lines or in a gentle arc shape may be set according to the contour shape of the opposing blades 32. In the shape shown in FIG. 3, the contour line from the first edge portion 53 to the second edge portion 53b is formed to be similar to the arc shape of the trailing edge shape (32a to 32c) of the blades 32 of the impeller 30.

[0026] The blades 32 of the impeller 30 are provided in a plurality of numbers so as to partition in the circumferential direction across the annular groove of the shroud 31, and the opening surface of the annular groove is positioned to face the stationary flow path 12. The shape of the blade 32 is a three-dimensionally curved shape so that the pressure coefficient becomes high, and a straight portion 32a in which the blade shape of the impeller extends linearly in the radial direction is formed from the inner peripheral side to the outer peripheral side at the rear end side edge portion, and a large arc portion 32b is formed outside the straight portion 32a. That is, it has a shape that finally blocks the flow from the stationary flow path 12 to the blade 32 side at the flow center where the flow fluctuation is the smallest. The blade 32 is connected to the shroud 31 at the end surface 32c on the outer peripheral side of the arc portion 32b. In FIG. 3, the contour of the connection edge at the front end of the blade 32, that is, the portions of the arrows 32d to 32f will also be visible. The connection position of the inner side portion of the blade 32 indicated by the arrow 32d with the shroud 31 is at a position that is retracted in the rotational direction from the position of the radial center portion of the blade 32 indicated by the arrow 32e. Conversely, the connection position of the radially outer side portion of the blade 32 indicated by the arrow 32f with the shroud 31 is at a position that is curved in the rotational direction. Since the blade 32 and the shroud 31 are manufactured as metal castings, there are no gaps or joints at these connection sites. Thus, in the present embodiment, the blade 32, which was conventionally prepared separately and fixed to the shroud 31 by welding or the like, is integrally manufactured, so that the air flow, particularly the air flow in the direction of rotation with respect to the circumferential axis, can flow smoothly in the individual spaces 35 partitioned by the blade 32.

[0027] FIG. 4 is the same figure as FIG. 3 and is a diagram for explaining the positional relationship between the outer edge positions of the suction passage 14 and the discharge passage 17 and the partition plate 50. Here, when looking at the suction passage 14 side, the outer peripheral edge 52 of the partition plate 50 is formed in an arc shape, and the distance from the rotation axis line A1 to the outer peripheral edge 52 is constant. On the suction passage 14 side, when comparing the circular projection range of the cross-sectional shape of the suction passage 14 with the position of the partition plate 50, most of the projection range on the inner peripheral side of the suction passage 14 is covered by the partition plate 50, but there is a portion having an interval of the arrow 61 near the outermost periphery where the projection range of the suction passage 14 is not covered by the partition plate 50. On the other hand, when looking at the discharge passage 17 side, in addition to the fact that the projection range of the discharge passage 17 is not covered by the partition plate 50 at the portion including the arrows 62 and 63 near the outermost periphery, there are portions where the projection range of the discharge passage 17 is not covered by the partition plate 50, such as the arrows 64 and 65, near the end on one side in the circumferential direction (the upwind side when looking at the air flow). Thus, the discharge-side end edge 53 and the outer peripheral edge 52 of the partition plate 50 are in a positional relationship such that both partially cover the projection range of the discharge passage 17. In this way, in the discharge passage 17, since a part of the portion away from the suction passage 14 is not covered by the partition plate 50, the air flow on the discharge passage 17 side is improved.

[0028] FIG. 5 is a perspective view showing the shape of the impeller 30 of the vortex blower 1 of the present embodiment. A plurality of blades 32 of the impeller 30 are provided so as to partition in the circumferential direction across an annular groove formed in the stationary flow path 12 of the casing 10. Individual spaces 35 partitioned between adjacent blades 32 are partitioned into a plurality of spaces at equal intervals in the rotation direction of the rotation axis A1, and open only on the rear side (casing 10 side) in the direction of the rotation axis A1, and are non-through spaces that do not open on the front side (casing cover 40 side) in the direction of the rotation axis A1. The air flowing from the stationary flow path 12 of the casing 10 to the blade 32 side flows out from the blade 32 side into the stationary flow path 12 of the casing 10, and rotates so as to enter the space 35 from the stationary flow path 12 and moves from the suction passage 14 to the discharge passage 17 along the radial direction of the stationary flow path 12. The air flowing from the stationary flow path 12 into the blade 32 side as indicated by the arrow 37a enters the non-through space 35 between the blades 32, circulates in the through space 35 while being accelerated by the rotating blades 32, and then flows out from the blade 32 side again as indicated by the arrow 37b and flows into the stationary flow path 12. At this time, the air entering from the inner peripheral side of the impeller 30 flows in a curved shape within the blade 32 and is accelerated by centrifugal force, and then flows out from the outer peripheral side of the impeller 30 into the stationary flow path 12.

[0029] The pressure rise of the vortex blower 1 is achieved by repeating the process in which the flow that has been accelerated from the inner periphery to the outer periphery in the blade 32, which aims to increase the static pressure by means of a three-dimensional structure, enters the stationary flow path 12, is decelerated and pressurized while being guided to the inner peripheral side along the shape of the stationary flow path, and then flows into the blade 32 again from the inner peripheral side and the pressure rises. In this way, the flow repeatedly swirls like a vortex several times to increase the pressure. Therefore, the pressure of the vortex blower is determined by (pressure rise per blade) × (number of swirls). The air (fluid) whose pressure has been increased circulates in the blade 32 and the stationary flow path 12, moves in the circumferential direction, is further compressed, and is discharged to the outside from the discharge passage 17.

[0030] As described above, since the space 35 of the impeller 30 of the present embodiment is covered by the non-penetrating shroud 31 on the front side, it will only open to the side facing the stationary flow path 12 on the rear side. The manufacturing method of the impeller 30 with this shape can be integrally manufactured using a mold. As the manufacturing means of the impeller 30 by the mold, die casting or other casting techniques can be used.

[0031] FIG. 6 is a view of the impeller 30 alone of the vortex blower 1 of the present embodiment. FIG. 6(a) is a rear view of the impeller 30 (a view of the impeller 30 seen from the rear side of the vortex blower 1), and (b) is a cross-sectional view of the B-B' portion passing through the rotation axis A1. The impeller 30 is driven by the electric motor 4 by being fixed to the rotation shaft 5 (see FIG. 1). A cylindrical mounting portion 36 is formed at the rotation center of the impeller 30. The inner surface 36a of the mounting portion 36 is cylindrical, but in a part of the rotation direction, a key groove 36b is formed to prevent the impeller 30 from idling with respect to the rotation shaft 5 by engaging with a key (not shown) formed on the rotation shaft 5. The screw hole 39 is used when removing the impeller 30. A disk-shaped disk portion 34 is formed on the outer side in the radial direction of the mounting portion 36, and is connected to a shroud 31 formed in an annular shape on the outer side of the disk portion 34. A curved portion 33 is formed inside the shroud 31. The cross-sectional shape orthogonal to the circumferential direction of the curved portion 33 is hemispherical as can be seen in FIG. 6(b). Although the blade 32 is not shown in the cross-sectional position in FIG. 6(b), as can be seen from FIG. 6(a), 20 blades 32 are formed in the circumferential direction.

[0032] The shape of the blade 32 is a three-dimensionally complex shape rather than a planar shape. A straight portion 32a is formed from the inner peripheral side to the outer peripheral side. Outside the straight portion 32a, it becomes a large arc portion 32b, and at the end face 32c of the arc portion, it is connected to the outer peripheral edge of the shroud 31 of the impeller 30. The front side of the blade 32 is connected to the curved portion 33 of the shroud 31 at a position 32d where the inner part retreats more than the rotation direction, and from there, it gradually heads forward in the rotation direction and is connected to the curved portion 33 at the position of the arrow 32e, and is connected to the outermost surface of the shroud 31 near the arrow 32f. Although the blade 32 has such a complex shape, on the other hand, its shape is determined so that integral molding by casting is possible.

[0033] Figure 7 is a cross-sectional view of the expanded state of the A-A' portion in Figure 3. The partition plate 50 serves to guide the air that has expanded when the impeller 30 reaches the discharge passage 17 as discharge air 86 by cutting it with the blade 32, and to prevent the backflow of air from the discharge side to the suction side. This is because if the air backflows, sufficient pressure cannot be built up and the performance will deteriorate. When the partition plate 50 is sufficiently long on the upwind side, the effect of preventing backflow is enhanced, but the performance deteriorates due to the partition plate 50 blocking the flow path. In this embodiment, by configuring the discharge passage 17 and the discharge-side shape of the partition plate 50 to partially overlap in the rotation axis direction, it is possible to prevent backflow from the discharge passage 17 to the suction passage 14 side and smoothly flow the air into the discharge passage 17 without stagnation. The number of blades 32 (partition number) accommodated behind the partition plate 50 is adjusted to the number at which the pressure on the discharge side becomes the highest. Regarding the problem of noise, it is considered that the pressure fluctuation on the discharge side is smaller and the generation of sound is also smaller compared to the suction side of the stationary flow path 12. Therefore, by making the effective stationary flow path longer and increasing the number of times the air swirls in the stationary flow path 12, it is possible to increase the pressure without increasing the noise. Thus, it is preferable to configure the partition plate 50 to partially overlap the projection range of the discharge passage 17 in the direction of the rotation axis line A1.

[0034] On the front side of the suction passage 14, a partition plate 50 protrudes in the circumferential direction and is configured to cover the entire suction passage 14 when viewed in the circumferential direction. The suction-side end edge 54 (see FIG. 4) of the partition plate 50 extends in a direction crossing the projection range of the suction passage 14 in the direction of the rotation axis A1. Here, it can be understood that the ridge line portion 58 of the suction-side end edge 54 of the partition plate 50 extends to the leeward side beyond the projection range on the suction passage 14 side. Since the partition plate 50 is configured to cover substantially the entire suction passage 14 in this way, the suction passage 14 does not directly face the rear end surface (arc portion 32b) of the blade 32. On the other hand, in the portion of the discharge passage 17 that is not covered by the discharge-side end edge 53, that is, in the portion of the arrow 38, the blade 32 directly faces the opening portion of the discharge passage 17.

[0035] When the impeller 30 is rotated by the electric motor 4, air flows into the impeller 30 from the stationary flow path 12 as shown by the arrow 81, guided by the suction passage 14. The inflowing air is accelerated from the inner circumference toward the outer circumference in the space 35 between the blades 32 of the impeller 30, and as shown by the arrows 22a and 22b in FIG. 13, it is guided in the circumferential direction in the stationary flow path 12, decelerated, and pressurized. The process of flowing into and being discharged from the space 35 of the impeller is repeated. In this way, the air between the stationary flow path 12 and the impeller 30 flows in a spiral shape and is repeatedly pressurized by the impeller 30 while kinetic energy is imparted thereto. The pressurized air is guided to the outside through the discharge passage 17 as shown by the arrow 86 in FIG. 7.

[0036] In this embodiment, a separate partition plate 50 is provided on the front side of a partition wall 20 that partitions between both ends of the stationary flow path 12. The cross-sectional shapes of the partition plate 50 and the discharge-side end edge 53 are formed in a tapered shape in which the plate thickness gradually increases from the end portion. The position of the surface 50a of the partition plate 50 in the direction of the rotation axis A1 is the same as the position of the disk portion 13 (see FIG. 1). Note that the position of the surface 50a of the partition plate 50 as viewed in the direction of the rotation axis A1 is substantially the same as the opening surface of the annular stationary flow path 12. On the suction passage 14 side of the partition plate 50, by cutting the plate thickness of the partition plate 50 from the surface 50a side and the back surface 50b side, as shown in FIG. 7, the tapered surface is formed to be inclined in the rotation direction, so that the suction air indicated by the arrow 81 efficiently flows into the space (expansion space 23) immediately after reaching the stationary flow path 12.

[0037] The gap C1 as viewed in the direction of the rotation axis A1 between the partition plate 50 and the impeller 30 is set to about 0.3 to 0.5 mm, and the gap C2 as viewed in the direction of the rotation axis A1 of the expansion space 23 is set to about 5 mm. Since the gap C2 of the expansion space 23 is set larger than the gap C1, the carry-over flow expands and is decompressed in the expansion space 23. If the gap dimension of the expansion space 23 is made too large, the carry-over flow transferred to the outer peripheral portion is likely to flow out to the inner peripheral side of the stationary flow path 12, resulting in performance degradation, or pressure fluctuations due to rapid expansion may occur, which may become a new noise source. However, by adjusting the size of the gap C2, it is possible to impart directivity to the flow of the expanded air and suppress the generation of noise due to the wind noise.

[0038] As described above, in this embodiment, the partition plate 50 is provided so as to partially cover the suction passage 14, and the suction side edge 54 is provided at a position crossing the suction passage 14. The discharge side edge 53 is provided at a position crossing the discharge passage 17 so as to partially cover the discharge passage 17. As a result, the circumferential length of the partition plate 50 including the partition plate 50 and the discharge side edge 53 can be made slightly shorter than the case where the partition plate 50 and the discharge side edge 53 entirely cover the suction passage 14 and the discharge passage 17, respectively. The minimum circumferential length of the partition plate 50 is set to a length that prevents pressure leakage between the suction passage 14 and the discharge passage 17. Normally, if the partition plate 50 is set to a length corresponding to the circumferential interval for three blades, pressure leakage can be prevented. Also, if the number of blades 32 is increased, the circumferential length of the partition plate 50 can be shortened. Generally, however, when the number of blades is increased, the aerodynamic performance tends to deteriorate, and there is a limit to shortening the circumferential length of the partition plate 50. In the vortex blower 1 of the present invention, by making the circumferential length of the partition plate 50 correspond to the interval for five blades, the sealing performance between the suction passage 14 and the discharge passage 17 is ensured without degrading the aerodynamic characteristics.

[0039] FIG. 8 is a diagram showing the noise performance of the vortex blower 1. These are diagrams showing the noise performance of the present embodiment having the partition shape shown in FIG. 2 and the conventional example (comparative example) shown in FIG. 12. In this specification, the octave band center frequency refers to the center frequency of a frequency band (band) in which the frequency ratio of the upper limit to the lower limit is 1 octave with a certain frequency as the center. Also, the octave band divided into 1 / 3 is defined as the 1 / 3 octave band. The horizontal axis of each figure shows the 1 / 3 octave band, and the vertical axis shows the noise level [dB]. The upper (a) shows the noise characteristic 91 at a frequency of 50 Hz, and the lower (b) shows the result of the noise characteristic 94 at a frequency of 60 Hz. As described above, the pressure fluctuation on the discharge side is smaller than that on the suction side, and it is considered that the generation of sound is also small. Since the number of partition sheets having an effective seal in the rotational direction is the same, in this embodiment, a specific frequency range that is audible, particularly the portions of arrows 93 and 96, is equivalent to the noise characteristics 92 and 95 of the conventional example. Therefore, it is possible to improve the efficiency without increasing the noise, and the noise performance can be maintained at the same level as the comparative example.

[0040] FIG. 9 is a diagram showing the pressure performance curve 97 of the vortex blower 1, comparing the present embodiment having the partition shape shown in FIG. 2 with the conventional example shown in FIG. 12. The horizontal axis shows the air volume [m 3 / min], and the vertical axis shows the air pressure [kPa]. As a result of the comparison by the inventor, in this embodiment, compared with the pressure performance curve 98 of the conventional example (comparative example), while maintaining the maximum air pressure, an efficient flow path could be realized in the medium air volume range. Therefore, it was confirmed that the performance of the present embodiment exceeded that of the conventional example in terms of total performance.

Embodiment

[0041] Next, a second embodiment of the present invention will be described with reference to FIGS. 10 and 11. FIG. 10 is a front view of the casing 10 and the partition plate 60 of the vortex blower 1A according to the second embodiment of the present invention, and shows the position of the blades of the impeller 30 superimposed. In the second embodiment, compared with the vortex blower 1 shown in FIGS. 1 to 7, although the shape of the partition plate 60 is different, other components are the same. The shape of the partition plate 60 on the suction passage 14 side is the same as that of the partition plate 50 of the first embodiment in the region surrounded by the three screw holes 69a to 69c, but the size on the discharge passage 17 side is different from that of the first embodiment. The contour shape of the discharge-side end edge 63 of the partition plate 60 is formed to be the same as the shape of the blade 32 of the impeller 30. On the other hand, the overlap between the partition plate 60 and the projection range of the discharge passage 17 in the direction of the rotation axis A1 is smaller than the overlap in the first embodiment shown in FIGS. 3 and 4.

[0042] In the second embodiment, since the partition plate 60 is located in a small area within the projection range of the discharge passage 17, the air discharged by the partition plate 60 can be cut, and less air stays in the specific portion 90 near the discharge passage 17, forming an efficient flow path. To realize this configuration, the interval between the three screw holes 69a to 69c is narrowed, and the arrangement of the screw holes 39 on the casing 10 side is changed so that the triangle shown in FIG. 10 is slightly smaller than the triangle shown in FIG. 3. As a result, the position of the screw hole 69a and the discharge-side single side 63 of the partition plate 60 can be formed close to each other, and the area of the partition plate 60 overlapping the projection range of the discharge passage 17 can be made smaller than that of the first embodiment. Further, even if the positions of the screw holes 29 (see FIG. 1) and 69a are moved in this way, the discharge-side shape of the discharge-side single side 63 of the partition plate 60 can be formed as a curve along the contour shape of the blade 32 close to the partition plate 60. At this time, since the partition plate 60 is on the virtual straight line 25 connecting the rotation axis A1 and the center line of the discharge passage 17, the design freedom of the screw mounting position (screw hole 29: see FIG. 1) can be increased, and the mounting strength according to the casing 10 can be increased.

[0043] FIG. 11 is a cross-sectional view of the state developed in the C-C' cross-section of FIG. 10. The impeller 30 is the same as that used in the first embodiment, and the blade 32 is the same as the impeller 30 shown in FIGS. 4(a) and 5(a). The front side in the rotation direction of the blade 32 of the impeller 30 has a curved shape so as to be a concave surface, and as shown in FIG. 11, the rear end surface (arc surface 32b) of the blade 32 is formed to be curved toward the rotation direction. By rotating the impeller 30 by the electric motor 4, the air guided by the suction passage 14 and flowing into the space 35 of the impeller 30 from the stationary flow path 12 is accelerated from the inner circumference to the outer circumference in the space 35 between the blades 32 of the impeller 30 and then discharged to the stationary flow path 12 side, and is decelerated and pressurized by being guided in the circumferential direction while rotating in the stationary flow path 12, and the process of flowing into the centrifugal groove 35 again is repeated. In this way, the air sucked into the vortex blower 1 is pressurized by repeatedly having kinetic energy imparted by the impeller 30 while flowing in a spiral shape as shown by the arrows 22a and 22b shown in FIG. 13. The pressurized air is guided to the outside through the discharge passage 17. At this time, since the tip of the impeller 30 extends slightly toward the discharge passage 17 side, a part of the discharge side end surface 63 of the partition plate 60 can guide the discharged air 186 to face the discharge passage 17.

[0044] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the shapes of the partition plates 50 and 60, particularly the shape near the suction opening 15 on the suction passage 14 side, may be formed in other shapes as long as they do not disturb the flow of the suction air 81 shown in FIGS. 7 and 11. Further, the shape of the blade 32 of the impeller 30 used may be changed. Also, even if the blade 32 and the shroud 31 of the impeller 30 are not integrated and are connected by welding as in the conventional manner, the partition plates 50 and 60 according to the present invention can be applied. Furthermore, the above-described partition plates 50 and 60 may be made of not only metal but also other materials such as resin and ceramic.

Description of Reference Numerals

[0045] 1 Vortex blower 4 Electric motor 5 Rotating shaft 10 Casing 11 Through hole 12 Stationary flow path 13 Disk part 14 Suction passage 14b Thread part 15 Suction opening 16 Protrusion 17 Discharge passage 18 Discharge opening 19 Protrusion 20 Partition wall 22 Air flow 23 Expansion space 25 Virtual straight line 30 Impeller 31 Shroud 31a Outer edge position 32 Blade 33 Curved part 34 Disk part 35 (Centrifugal) space 36 Mounting part 36a Inner surface 36b Key groove 39 Thread hole 40 Casing cover 50 Partition wall plate 50a Surface 50b Back surface 51 Inner peripheral edge 52 Outer peripheral edge 53 Discharge side end face 53a First edge part 53b Second edge part 54 Suction side end face 55a Surface 55b Back surface 56a Main taper surface 56b Upper taper surface 56c Lower taper surface 57a Recess 57b Guide surface 57c Notch part 57d Front side taper surface 58 Ridge line part Thread holes 59a to 59c Partition plate 60 Discharge side end face 63 Suction side end face 64 Thread holes 69a to 69c Suction air 81 Exhaust air 86 Threads 89a to 89c

Claims

1. An electric motor having a rotating shaft, A casing having a stationary flow path formed by an annular groove centered on the rotating shaft, A suction passage and a discharge passage connected in a direction parallel to the rotating shaft at both ends of the stationary flow path, An impeller driven by the electric motor and defining a centrifugal space with an opening surface facing the stationary flow path, A casing cover covering the impeller, The impeller includes a plurality of blades provided at predetermined intervals in the circumferential direction and arranged in an annular shape, The casing is provided with a partition wall that partitions the suction passage and the discharge passage in the rotational direction, A partition plate is provided between the partition wall and the impeller so as to cover at least a part of the discharge passage, The contour of the partition plate on the discharge passage side is formed in the same contour shape as the end face shape of the blade close to the partition plate, A vortex blower, characterized in that, when viewed from the axial direction of the impeller's rotation axis, the partition plate and the discharge passage are formed so as to overlap only a part on the side closer to the suction passage in the circumferential direction.

2. The circumferential cross-sectional shape of the stationary flow path is semi-circular, the circumferential cross-sectional shape of the casing of the impeller is semi-circular, and the opening side of the groove of the stationary flow path and the opening side of the impeller are arranged to face each other, The partition plate is screwed to the partition wall of the casing, and the vortex blower according to claim 1 is characterized in this regard.

3. The vortex blower according to claim 2, characterized in that, when viewed from the axial direction of the impeller's rotation axis, the suction passage and the partition plate are shaped to overlap.

4. The partition plate, when viewed from the axial direction of the rotation axis, has a shape having a portion overlapping the discharge passage from the radially inner side and a portion overlapping the discharge passage from the side closer to the suction passage in the circumferential direction, and the vortex blower according to claim 1 is characterized in this regard.

5. The vortex blower according to claim 4, wherein the partition plate is disposed at a position intersecting a virtual plane connecting the rotation axis and the central axis of the discharge passage.

6. The vortex blower according to claim 5, wherein the partition plate is formed so as to overlap the suction passage except for a part on the outer side in the radial direction when viewed from the rotation axis direction.

7. The impeller has a shroud provided with a curved portion and a plurality of blades formed so as to divide a circumferentially continuous space formed by the curved portion, The vortex blower according to claim 6, wherein the shroud and the blades are formed of an integral structure of metal, and an edge portion of the blade on the side opposite to the casing is connected to an inner wall surface of the shroud without a gap.

8. The rotation axis of the electric motor is disposed coaxially with the rotation center of the impeller, The vortex blower according to claim 7, wherein the partition plate is fixed between the suction passage and the discharge passage at a position radially away from the rotation center.

9. An electric motor, A casing provided with an arc-shaped stationary flow path centered on a rotation axis, and a suction passage and a discharge passage located at ends of the stationary flow path, An impeller provided at predetermined intervals in the circumferential direction corresponding to the stationary flow path and arranged in an annular shape, and having a plurality of blades with a three-dimensionally curved shape, A partition plate provided between the casing and the impeller when viewed in the rotation axis direction, and detachably attached to the casing by a fixture so as to cover a part of the discharge passage and a part of the suction passage, And a casing cover covering the impeller. The impeller has a shroud with a semi-circular cross-sectional shape in the circumferential direction, and the blade is integrally formed without a gap with the wall surface without the shroud within the semi-circular region of the shroud. A vortex blower, characterized in that, when viewed from the axial direction of the rotation axis of the impeller, the discharge passage and the partition plate overlap only a part on the side closer to the suction passage in the circumferential direction and only a part in the radial direction.

10. The blade has a three-dimensionally curved shape. The outer edge shape of the end portion of the partition plate on the discharge passage side is formed with the same contour shape as the end face shape of the blade exposed on the partition plate side of the blade, and The vortex blower according to claim 8, characterized in that, when viewed from the axial direction of the rotation axis of the impeller, the discharge passage and the partition plate overlap only a part on the side closer to the suction passage in the circumferential direction and only a part in the radial direction.

Images