JP2017048779A - Centrifugal Pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal pump capable of achieving reduction in weight while maintaining strength of an impeller.SOLUTION: In a centrifugal pump, an impeller having a plurality of flow passages for communicating an internal space of the shaft center and an outer space on the outside in a radial direction is arranged inside a pump case. The impeller includes: a floor part 12 having a mounting hole 12a in which a rotary shaft is fixed at the shaft center; an umbrella member in which a fluid introduction hole is provided in the shaft center, and which is provided so as to oppose to the floor part 12 in the axial direction; and a plurality of flow passage constitution parts 13 provided in the circumferential direction by extending in the axial direction up to the umbrella member from the floor part 12, and for constituting the flow passages together with the floor part 12 and the umbrella member. The flow passage constitution part 13 includes a hollow part 21 which has a first side wall 13a on the rotation direction side in the flow passage, a second side wall 13b on the opposite side of the rotation direction in the flow passage, and an outer peripheral wall 13c for connecting the outside portions in the radial direction of the first side wall 13a and the second side wall 13b with each other and, thereby, which is surrounded by them. A reinforcement rib 22 is provided on a floor part 12 in the hollow part 21.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a centrifugal pump.

  Conventionally, as a centrifugal pump, an impeller having a plurality of flow passages that communicate an inner space at the center of the shaft and an outer space radially outside is disposed inside the pump case, and the impeller is rotated by rotating the impeller. There is one that allows a fluid to be led from the space side to the external space side through a flow passage (for example, see Patent Document 1). In the impeller of this centrifugal pump, a plurality of substantially fan-shaped flow path constituting portions whose circumferential width becomes wider toward the outer side in the radial direction are formed in the circumferential direction, and a flow passage having a constant width is constituted by the opposing wall surfaces. ing.

JP 2004-278111 A

  However, the impeller of the centrifugal pump as described above has a problem that the flow path component is a substantial fan-shaped solid body and the weight of the impeller is large. This causes a resonance when the rotating body including the impeller rotates.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a centrifugal pump capable of reducing the weight while maintaining the strength of the impeller.

  A centrifugal pump that solves the above problem is a centrifugal pump in which an impeller having a plurality of flow passages that communicates an internal space at the center of the shaft and an external space radially outside is disposed inside a pump case, The impeller has a floor portion having an attachment hole in which a rotation shaft is fixed at the center of the shaft, and an umbrella portion provided with a fluid introduction hole at the center of the shaft so as to face the floor portion in the axial direction; A plurality of flow path components in the circumferential direction that are arranged between the floor portion and the umbrella portion and constitute the flow path together with the floor portion and the umbrella portion; and A first side wall on the rotational direction side in the flow path, a second side wall on the counter-rotation direction side in the flow path, and an outer peripheral wall connecting the radially outer sides of the first side wall and the second side wall. A hollow portion surrounded by them, and inside the hollow portion That the reinforcing ribs are provided on the floor.

  According to this configuration, since the flow path component includes the hollow portion and the reinforcing rib is provided in the hollow portion, the weight can be reduced while maintaining the strength of the impeller. As a result, for example, resonance at the time of rotation of the rotating body including the impeller can be suppressed.

In the centrifugal pump, it is preferable that the reinforcing rib is provided so as to be connected to the outer peripheral wall.
According to this configuration, since the reinforcing rib is provided so as to be connected to the outer peripheral wall, it is possible to prevent the outer peripheral wall that is farthest away from the center of the shaft and is subjected to a large centrifugal force from falling down radially outward.

In the centrifugal pump, it is preferable that the reinforcing ribs extend radially around the mounting hole.
According to this configuration, since the reinforcing ribs provided so as to be connected to the outer peripheral wall extend radially around the mounting hole (that is, the rotation axis center), it is possible to further suppress the outer peripheral wall from falling down radially outward. it can.

In the centrifugal pump, it is preferable that a thick wall portion in the axial direction is provided on the axial center side of the floor portion.
According to this configuration, since the thick wall portion in the axial direction is provided on the axial center side of the floor portion, it is possible to reduce the weight on the outer side in the radial direction where a large centrifugal force is applied, and on the base side with respect to the rotating shaft. The strength can be improved, and further, the shaft can be fixed to the rotating shaft in a long range in the axial direction. Thereby, the resonance at the time of rotation of the rotary body containing an impeller can be suppressed more.

In the centrifugal pump, it is preferable that the axial height of the flow passage is set lower on the radial outer side than on the axial center side.
According to this configuration, the axial height of the flow passage is set lower on the radially outer side than on the axial center side, so that the axial height (axial width) of the outer peripheral wall can be reduced. The friction between the outer peripheral wall and the fluid can be reduced, and the efficiency can be improved.

In the centrifugal pump, it is preferable that the width of the flow passage is set wider on the radially outer side than on the axial center side.
According to this configuration, the axial height of the flow passage is set lower on the radially outer side than the axial center side, and the width of the flow passage is set wider on the radially outer side than the axial center side. The passage area of the passage (area in the direction perpendicular to the fluid flow) can be made substantially constant. Therefore, the change in the flow velocity of the fluid passing through the flow passage can be reduced, and the loss can be reduced and the efficiency can be increased as compared with the case where the change in the flow velocity is large.

  In the centrifugal pump, the flow path component extends radially inward from a common radial inner end of the first side wall and the second side wall and forms a part of the rotational side wall surface of the flow passage. However, it is preferable to have a common wall that also constitutes a part of the side surface in the counter-rotating direction.

  According to this configuration, a large flow path can be secured on the radially inner side where the space is narrow. Therefore, for example, the number of flow paths can be increased. Further, for example, since the area of the outer peripheral wall can be reduced, the friction (loss) between the outer peripheral wall and the fluid can be reduced, and the efficiency can be improved. In addition, for example, the radial length of the first side wall and the second side wall can be shortened, and the circumferential distance of the outer peripheral wall can be shortened by narrowing the circumferential interval, so that the flow path component is bent. (Falling) becomes difficult, and it becomes possible to secure more strength.

  In the centrifugal pump of the present invention, it is possible to reduce the weight while maintaining the strength of the impeller.

The partial sectional view of the centrifugal pump in one embodiment. (A) is a top view of the 1st impeller member in one embodiment. (B) is a bottom view of the first impeller member. The partial cross section perspective view of the 1st impeller member in one Embodiment. (A) is a top view of the umbrella member in one embodiment. (B) is a bottom view of the umbrella member. (A) is a partial perspective view for demonstrating the balance adjustment process and the recessed part for balance adjustment in one Embodiment. (B) is sectional drawing for demonstrating the balance adjustment process and the recessed part for balance adjustment similarly. Sectional drawing of the centrifugal pump in another example. Sectional drawing of the centrifugal pump in another example. The schematic diagram which looked at the 2nd case of the centrifugal pump in another example from the axial direction. (A) is the schematic diagram which looked at the fin in another example from the axial direction. (B) is the schematic diagram which looked at the fin in another example from the side. The top view of the 1st impeller member in another example. The bottom view of the umbrella member in another example. Sectional drawing for demonstrating the impeller in another example. The top view of the 1st impeller member in another example. The top view of the 1st impeller member in a reference example.

Hereinafter, an embodiment of a centrifugal pump will be described with reference to FIGS.
As shown in FIG. 1, the centrifugal pump according to the present embodiment is an air pump, and includes a motor 1, a pump case 2, and an impeller 3.

  The motor 1 of the present embodiment is a brushless motor, and includes a stator 5a fixed to the inner peripheral surface of a substantially bottomed cylindrical motor case 4, and a rotor 5b supported rotatably inside the stator 5a. Have The motor 1 of the present embodiment is a motor in which the number of magnetic poles of the rotor 5b is 4 and the number of slots between teeth of the stator 5a is 6 slots.

  The pump case 2 includes a first case 6 that is fixed so as to substantially close the opening end of the motor case 4, and a second case that is fixed to the opposite side of the motor 1 (motor case 4) of the first case 6. 7.

  A center hole 6a is formed at the center of the first case 6, and one end side of the rotary shaft 9 of the rotor 5b is supported on the inner peripheral surface of the center hole 6a via a bearing 8. A circular recess 6 b is formed on the end surface of the first case 6 on the second case 7 side as viewed from the axial direction of the rotary shaft 9. Further, a spiral chamber constituting groove 6c is formed on the outer peripheral side of the recess 6b on the end surface of the first case 6 on the second case 7 side. The bottom surface of the spiral chamber constituting groove 6c is a sectional curved portion 6d having a curved cross section, and the side surface of the spiral chamber constituting groove 6c is a straight sectional straight portion 6e having a sectional shape along the axial direction (of the rotating shaft 9). ing.

  An air introduction hole 7 a is formed at the center of the second case 7. The air introduction hole 7a penetrates along the axial direction of the rotary shaft 9 and is formed so that its diameter becomes smaller toward the motor 1 side (first case 6 side). Further, the first case has a diameter A2 larger than the diameter A1 of the end portion of the air introduction hole 7a on the motor 1 side than the air introduction hole 7a in the second case 7 on the motor 1 side (first case 6 side). A communication hole 7d opened on the 6 side is formed. The communication hole 7 d has a constant diameter A2 in the axial direction of the rotary shaft 9. In addition, a circular recess 7b is formed on the end surface of the second case 7 on the first case 6 side when viewed from the axial direction of the rotary shaft 9, and the recess 7b together with the recess 6b of the first case 6 is an impeller housing portion. 10 is constituted. Further, a spiral chamber constituting groove 7e is formed on the outer peripheral side of the recess 7b on the end surface of the second case 7 on the first case 6 side, and the spiral chamber constituting groove 7e together with the spiral chamber constituting groove 6c of the first case 6 is formed. A spiral chamber U is formed. The bottom surface of the spiral chamber constituting groove 7e is a curved section 7f having a curved cross section, and the side surface of the spiral chamber constituting groove 7e is a straight section linear portion 7g having a cross section along the axial direction (of the rotating shaft 9). ing. In other words, in the present embodiment, the side surface constituting the spiral chamber U has a straight section 6e on the first case 6 side and a straight section 7g on the second case 7 side along the axial direction of the rotary shaft 9. It has a straight shape. In addition, an air discharge tube portion 7 c that communicates with the spiral chamber U located on the radially outer side of the impeller housing portion 10 is formed in a part of the second case 7 in the circumferential direction.

  An annular seal groove 6f is formed on the mating surface of the first case 6 with the second case 7 at a position radially outside of the spiral chamber U, and the second case 7 is aligned with the seal groove 6f. A seal ring S <b> 1 that is crushed by the surface and held is accommodated. Thereby, the leakage from the mating surface of the fluid passing through the spiral chamber U is prevented.

  The impeller 3 is fixed to the one end of the rotating shaft 9 protruding into the impeller accommodating portion 10 so as to be integrally rotatable, and is arranged in the impeller accommodating portion 10. The impeller 3 has a plurality of flow passages 11 that connect the inner space at the center of the shaft and the outer space (the spiral chamber U) on the outer side in the radial direction, and is rotated from the inner space side through the flow passage 11. Then, the air as the fluid is led out to the external space side, and the air is ejected from the air discharge cylinder portion 7c. Further, the impeller 3 of the present embodiment is set so that the diameter of the impeller 3 is larger than the diameter of the rotor 5b.

  Specifically, as shown in FIGS. 1 to 3, the impeller 3 includes a substantially disc-shaped floor portion 12 having an attachment hole 12 a to which the rotation shaft 9 is fixed at the axial center, and an axial direction from the floor portion 12. A first impeller member 14 having a plurality of flow path constituting portions 13 in the circumferential direction provided extending in the direction is provided.

  As shown in FIGS. 1 and 4, the impeller 3 is provided with a fluid introduction hole 15 a at the center of the shaft, and as a substantially disk-shaped umbrella portion provided so as to face the floor portion 12 in the axial direction. The umbrella member 15 is provided. The umbrella member 15 is fixed to the tip of the flow path component 13 that extends in the axial direction from the floor 12. In other words, the flow path component 13 extends in the axial direction from the floor 12 to the umbrella member 15, and is disposed between the floor 12 and the umbrella member 15. The plurality of flow path constituting portions 13 in the circumferential direction constitute a plurality (four in the present embodiment) of the flow passages 11 in the circumferential direction together with the floor portion 12 and the umbrella member 15. The fluid introduction hole 15a extends along the axial direction of the rotary shaft 9 at the axial center of the umbrella member 15, and is an inner peripheral surface of the introduction cylinder portion 15d accommodated in the communication hole 7d of the second case 7. The diameter (inner diameter) A3 is set to be the same as the diameter A1 of the end portion of the air introduction hole 7a on the motor 1 side. The introduction cylinder portion 15d has an outer diameter that is constant in the axial direction and is set slightly smaller than the diameter A2 of the communication hole 7d, and is accommodated with a slight gap inside the communication hole 7d. Yes.

  Here, as shown in FIGS. 2A and 3, the flow path component 13 of the present embodiment includes a first side wall 13 a on the rotational direction side in the flow passage 11 and a counter-rotation direction in the flow passage 11. By having the second side wall 13b on the side and the outer peripheral wall 13c that connects the outer sides in the radial direction of the first side wall 13a and the second side wall 13b, a hollow portion 21 surrounded by them is provided. More specifically, in the hollow portion 21, the radially inner side (tip portion) of the first side wall 13a and the radially inner side (tip portion) of the second side wall 13b are connected, and the diameter of the first side wall 13a and the second side wall 13b. The direction outer side (base end part) is formed by being connected by the outer peripheral wall 13c.

  A reinforcing rib 22 is provided on the floor portion 12 in the hollow portion 21. The reinforcing ribs 22 of the present embodiment extend radially outward from the mounting hole 12a as a center and are integrally provided so as to be connected to the outer peripheral wall 13c. Further, the reinforcing ribs 22 of the present embodiment are integrally formed so that the height in the axial direction is increased toward the radially outer side on the radially outer side, and is connected to the top of the outer peripheral wall 13c. Further, the reinforcing ribs 22 of the present embodiment are formed so that the length in the radial direction becomes longer toward the rotation direction side in each hollow portion 21.

  Further, as shown in FIG. 2A, when viewed from the axial direction, the first side wall 13a and the second side wall 13b of the present embodiment are rotated in the rotational direction (counterclockwise in FIG. It is formed in a shape that is curved in the opposite direction (clockwise direction in FIG. 2). Specifically, the first side wall 13a of the present embodiment has an involute curve-shaped involute portion 13d on the radially inner side and an arc-shaped arc portion 13e on the radially outer side when viewed from the axial direction. ing. Further, the interval between the first side wall 13a and the second side wall 13b facing each other in the flow path component 13 adjacent in the circumferential direction, that is, the width of the flow passage 11 (width in the direction perpendicular to the direction in which the fluid flows) is The radially outer side is set wider than the axial center side. Further, the axial height of the flow path component 13 (see FIGS. 1 and 3), that is, the axial height of the flow passage 11 is set to be lower on the radially outer side than on the axial center side. Of course, the umbrella member 15 is thus formed in a disk shape with the radially outer side approaching the floor 12 side. Further, as shown in FIGS. 2A and 3, a fitting convex portion 13f is formed on a part of the top portion of the first side wall 13a. The fitting protrusions 13f of the present embodiment are provided at equidistant intervals from the center of the shaft and at equiangular intervals (in the present embodiment, 90 ° intervals) about the shaft.

  As shown in FIG. 4B, the umbrella member 15 has a fitting groove 15b so that the ends of the flow path component 13 (first side wall 13a, second side wall 13b, and outer peripheral wall 13c) are fitted. A fitting concave portion 15c into which the fitting convex portion 13f is fitted is formed in a part of the fitting groove 15b. The fitting recesses 15c of the present embodiment are provided at equidistant intervals from the center of the shaft and at equiangular intervals (in the present embodiment, 90 ° intervals) about the shaft. The fitting recess 15c is not limited to a concave shape, and may be a hole shape penetrating in the axial direction so as to be fitted with the fitting convex portion 13f.

Moreover, as shown in FIG.1 and FIG.3, the thick part 12b which is thick in the axial direction is provided in the axial center side of the floor part 12 of this embodiment.
In addition, as shown in FIGS. 1, 2B, 3 and 4A, the impeller 3 of this embodiment has balance adjustment protrusions 31 and 32 that protrude in the axial direction and can be deleted. doing.

  Specifically, as shown in FIG. 1, the balance adjustment protrusions 31 and 32 are provided at both ends in the axial direction of the impeller 3, that is, at the floor 12 (first impeller member 14) and the umbrella member 15. It has been. Further, the balance adjustment protrusions 31 and 32 are provided so as to protrude on the opposite side of the flow passage 11 in the floor portion 12 (first impeller member 14) and the umbrella member 15, respectively. The balance adjustment protrusions 31 and 32 are provided on the outer peripheral edge of the impeller 3. Further, the balance adjustment protrusions 31 and 32 are provided in an annular shape around the rotation center of the impeller 3. The rotating body including the impeller 3 and the rotor 5b can adjust the balance by deleting a part of the balance adjustment protrusions 31 and 32 by cutting or the like.

  That is, the centrifugal pump manufacturing method according to the present embodiment includes a “forming step” for forming the balance adjustment protrusions 31 and 32 that protrude in the axial direction and can be removed on the impeller 3, and one of the balance adjustment protrusions 31 and 32. A “balance adjusting step” for adjusting the balance of the rotating body including the impeller 3 by deleting the portion.

  Further, as shown in FIGS. 5A and 5B, in the “balance adjustment step” of the present embodiment, a part of the balance adjustment protrusion 32 (31) is deleted while leaving the outer peripheral edge. The balance adjustment recess 32a is formed on the radially inner side of the balance adjustment protrusion 32 (31) to adjust the balance of the rotating body including the impeller 3.

Next, the operation of the centrifugal pump configured as described above will be described.
When power is supplied to the motor 1, the rotor 5b is rotationally driven, and the impeller 3 is rotated together with the rotor 5b (rotating shaft 9). Then, air is introduced into the inner space at the axial center of the impeller 3 through the air introduction hole 7 a of the pump case 2, and the outer space radially outside the impeller 3 from the inner space side through the flow passage 11. Air is led to the spiral chamber U on the side. Then, the pressure of air increases in the spiral chamber U on the radially outer side of the impeller 3, and air is injected from the air discharge cylinder portion 7 c of the pump case 2.

Next, the characteristic effects of the above embodiment will be described below.
(1) Since the flow path component 13 includes the hollow portion 21 and the reinforcing rib 22 is provided on the floor portion 12 in the hollow portion 21, the weight can be reduced while maintaining the strength of the impeller 3. As a result, for example, resonance at the time of rotation of the rotating body including the impeller 3 can be suppressed.

  (2) Since the reinforcing rib 22 is provided so as to be connected to the outer peripheral wall 13c, it is possible to prevent the outer peripheral wall 13c that is farthest away from the axial center and is subjected to a large centrifugal force from falling down radially outward.

  (3) Since the reinforcing ribs 22 provided so as to be connected to the outer peripheral wall 13c extend radially around the mounting hole 12a (that is, the center of the rotation axis), the outer peripheral wall 13c is further prevented from falling down radially outward. Can do.

  (4) Since the thick wall portion 12b is provided in the axial direction on the axial center side of the floor portion 12, the base side with respect to the rotating shaft 9 is achieved while reducing the weight on the radially outer side where a large centrifugal force is applied ( The strength around the mounting hole 12a) can be improved, and further, it can be fixed to the rotary shaft 9 in a long range in the axial direction. Thereby, the resonance at the time of rotation of the rotary body containing the impeller 3 can be suppressed more, for example.

  (5) Since the axial height of the flow passage 11 is set lower on the radially outer side than on the axial center side, the axial height (axial width) of the outer peripheral wall 13c can be reduced, and the outer circumference The friction between the wall 13c and the fluid can be reduced, and the efficiency can be improved.

  (6) The axial height of the flow passage 11 is set lower on the radially outer side than the axial center side, and the width of the flow passage 11 is set wider on the radial outer side than the axial center side. 11 passage areas (areas in the direction perpendicular to the fluid flow) can be made substantially constant. Therefore, the change in the flow velocity of the air passing through the flow passage 11 can be reduced, and the loss can be reduced and the efficiency can be improved as compared with the case where the change in the flow velocity is large.

  (7) The first side wall 13a on the rotational direction side in the flow passage 11 has an involute portion 13d having an involute curve shape on the radially inner side and an arc portion 13e having an arc shape on the radially outer side when viewed from the axial direction. . In this way, it is possible to reduce the loss by suppressing the separation of the air flow, and to achieve high efficiency.

  (8) Since the fitting convex portion 13f and the fitting concave portion 15c are provided at equidistant intervals from the center of the shaft and at equiangular intervals (in the present embodiment, at 90 ° intervals), the floor portion 12 ( The first impeller member 14) and the umbrella member 15 can be easily fitted. For example, in this embodiment, even if the umbrella member 15 is rotated 90 ° × n (n is a natural number) in the circumferential direction, it can be fitted to the floor portion 12 (first impeller member 14).

  (9) As for the side surface constituting the spiral chamber U, the cross-sectional straight portion 6e on the first case 6 side and the cross-sectional straight portion 7g on the second case 7 side are axial directions of the rotating shaft 9 (first and second cases 6, 6). 7 assembling direction). With such a configuration, the cross-sectional straight portions 6e and 7g to be mated can be easily formed with high accuracy, and deviations at the mating surfaces of the first and second cases 6 and 7 can be suppressed to a small extent. The adverse effect on the fluid flow can be reduced.

  (10) Since the diameter (inner diameter) A3 of the fluid introduction hole 15a of the impeller 3 is set to be the same as the diameter A1 of the end portion of the air introduction hole 7a of the second case 7 on the motor 1 side, It is possible to suppress the occurrence of vortices. Further, since the air introduction hole 7a is formed so that the diameter thereof becomes smaller toward the motor 1 side (first case 6 side), for example, when the diameter is slightly smaller than the diameter A3 of the fluid introduction hole 15a, etc. The diameter A1 of the end portion on the motor 1 side can be easily adjusted (same as the diameter A3 of the fluid introduction hole 15a) by cutting or the like.

  (11) The outer diameter of the introduction cylinder portion 15d is constant in the axial direction, and the diameter (inner diameter) A2 of the communication hole 7d in which the introduction cylinder portion 15d is accommodated is also constant in the axial direction. Compared with the case where it is not, each can be easily shape | molded with high precision, and those clearance gaps can be set small. Therefore, for example, the backflow of the fluid from those gaps can be suppressed.

The above embodiment may be modified as follows.
In the above embodiment, although not particularly mentioned, a configuration may be provided that prevents air from freely leaking outside the motor case 4 through the center hole 6 a of the first case 6.

  For example, you may change as shown in FIG. In this example, the rotary shaft 9 is supported by the center hole 6 a of the first case 6 via the bearing 8 and supported by the center hole 4 a of the motor case 4 via the bearing 41. The bearings 8 and 41 are ball bearings. An annular sensor magnet 43 is externally fitted and fixed to the other end portion (upper end portion in FIG. 6) of the rotating shaft 9 protruding outside the motor case 4 through a resin fixing ring 42. A circuit board 45 is fixed to the end of the motor case 4 in the axial direction opposite to the first case 6 via a fixing member 44. Various elements such as a rotation sensor 46 that detects rotation (rotation angle, rotation speed, etc.) of the rotation shaft 9 are mounted on the circuit board 45 so as to face the sensor magnet 43.

  A substantially bottomed cylindrical sealing case 47 that covers the entire motor 1 is fixed to the first case 6. The sealed case 47 has a flange portion 47a extending radially outward at the opening end thereof, and a plurality of locations (only one location shown in FIG. 6) of the flange portion 47a penetrates the flange portion 47a to form the first case. It is fixed by a screw 48 screwed to 6. An annular seal groove 6g is formed on the mating surface of the first case 6 with the flange portion 47a. The seal groove 6g accommodates a seal ring S2 that is crushed and clamped by the mating surface of the flange portion 47a. ing. As a result, air leakage from the mating surface between the first case 6 and the flange portion 47a is prevented. A wiring hole 47 c is formed in the bottom 47 b of the sealed case 47. A sealing rubber member 50 that prevents air leakage from the wiring hole 47 c while passing through the wiring 49 is fitted into the wiring hole 47 c. The wiring 49 electrically connects an external control device or power supply device to the circuit board 45 or the winding 51 of the stator 5a.

  If it does in this way, it can prevent that the air by the side of the impeller accommodating part 10 leaks outside the motor case 4 freely via the center hole 6a etc. of the 1st case 6 by sealing. . Specifically, in a configuration in which the sealed case 47 is not provided, the impeller housing portion is interposed via a clearance of the bearing 8 provided in the center hole 6a of the first case 6 or a clearance of the bearing 41 provided in the motor case 4. There is a possibility that the air on the 10th side may freely leak to the outside, but this can be suppressed. Moreover, it can suppress that the grease of the bearings 8 and 41 flows out by the flow of air.

  In this example (see FIG. 6), the magnetic center position B1 in the axial direction of the rotor 5b made of a permanent magnet is shifted by a slight length C toward the impeller 3 from the magnetic center position B2 in the axial direction of the stator 5a. Is set to Thereby, the force which goes to the other end side (upper side in FIG. 6) of the rotating shaft 9 is applied to the rotor 5b, the rotating shaft 9, and the impeller 3. Therefore, even if the impeller 3 sucks air from the air introduction hole 7a side during driving and a force directed to the air introduction hole 7a side (lower side in FIG. 6) is applied to the impeller 3, the force is offset. Can do. As a result, for example, the axial load applied to the bearings 8 and 41 can be reduced, and the life of the bearings 8 and 41 can be extended. In this example, the magnetic center position B1 of the rotor 5b is shifted with respect to the magnetic center position B2 of the stator 5a to generate a force toward the other end side (the upper side in FIG. 6) of the rotary shaft 9. However, the present invention is not limited to this, and the same force may be generated by setting the magnetization direction (orientation direction) of the permanent magnet constituting the rotor 5b to the oblique axis direction. For example, the permanent magnet has a magnetization direction toward the axially upper side (anti-impeller 3 side) as it goes radially outward (stator 5a side) and an axially lower side as it goes radially inward (rotary shaft 9 side). The magnetization direction is set so that the magnetization direction toward the impeller 3 side) is alternately arranged in the circumferential direction.

  For example, as shown in FIG. 7, you may change. In this example, a substantially bottomed cylindrical sealing case 52 that covers the center hole 4a of the motor case 4, the circuit board 45, and the like is fixed to the bottom of the motor case 4 (the upper end in FIG. 7). An annular seal groove 6h is formed on the mating surface of the first case 6 with the flange portion 4b of the motor case 4, and the seal ring 6h is crushed and clamped by the mating surface of the flange portion 4b. S3 is accommodated.

  Even in this case, similarly to the above-described another example (see FIG. 6), the air on the impeller housing portion 10 side is sealed outside the motor case 4 via the center hole 6a of the first case 6 and the like. Can be prevented from leaking freely.

  In the above embodiment and other examples, the motor case 4, the first case 6, the second case 7, and the sealed cases 47 and 52 are preferably made of aluminum, although not particularly mentioned. The impeller 3 may also be made of aluminum. Further, a heat conductive silicon rubber may be interposed between the motor case 4 and the first case 6 or between the first case 6 and the second case 7. If it does in this way, it will become easy to conduct the heat which occurred in motor 1, and it can radiate favorably. Of course, the motor case 4, the first case 6, the second case 7, the sealing cases 47 and 52, the impeller 3 and the like may be made of other materials such as a resin material.

  Further, for example, as shown in FIGS. 8, 9A and 9B, fins 61 may be provided in the flow path of fluid (air) (in the spiral chamber U or the air discharge cylinder portion 7c). . The fin 61 of this example is provided in the linear flow path 62 connected from the spiral chamber U into the air discharge cylinder portion 7c. Moreover, the fin 61 of this example is formed long along the direction (see arrow W in FIG. 9A) in which the fluid (air) flows. Further, the fin 61 of this example is formed such that the width in the middle part in the longitudinal direction is wider (see FIG. 9A) and the height in the middle part in the longitudinal direction is higher (see FIG. 9B). Further, three fins 61 in this example are arranged side by side in a direction orthogonal to the direction in which the fluid (air) flows (see arrow W in FIG. 9A). In this way, the heat generated in the motor 1 can be radiated more satisfactorily. Further, since the fin 61 is formed along the direction in which the fluid (air) flows (see the arrow W in FIG. 9A), a fluid rectifying effect can also be obtained. Of course, the fins 61 may be provided at different positions in the fluid (air) flow path, for example, in the spiral chamber U, or in the air discharge cylinder portion 7c. Further, the number of fins 61 is not limited to three.

  In the above embodiment, the flow path component 13 is provided extending in the axial direction from the floor 12 of the first impeller member 14 to the umbrella member 15 and is disposed between the floor 12 and the umbrella member 15. However, it may be provided so as to extend in the axial direction from the umbrella member 15 as long as it is arranged between the floor 12 and the umbrella member 15.

  For example, you may change as shown in FIG.10 and FIG.11. That is, as shown in FIG. 10, the floor portion 12 of the first impeller member 71 of this example is provided with two flow path constituting portions 13 at intervals of 180 °, and between these circumferential directions. A fitting groove 72 similar to the fitting groove 15b of the umbrella member 15 of the above embodiment is provided. Moreover, as shown in FIG. 11, the umbrella member 73 of this example is provided with two fitting grooves 15b at an interval of 180 °, and between these circumferential directions, the flow path constituting portion of the above embodiment is provided. 13 is provided. If it does in this way, both the intensity | strength (rigidity) of the 1st impeller member 71 and the umbrella member 73 can be made high.

  Further, for example, it may be changed as shown in FIG. In this example, the flow path component 13 is not provided on the floor 12 of the first impeller member 75, and only the umbrella member 76 has a flow channel component 77 similar to the flow channel component 13 of the above embodiment. Is provided. In this example, the front end surface (the upper end surface in FIG. 12) of the flow path component 77 is formed on a single plane orthogonal to the axial direction of the rotary shaft 9. If it does in this way, the tip end face of channel constituent part 77 can be formed easily with high precision, and the gap in the mating face of this tip end face and the 1st impeller member 75 (floor part 12) is suppressed small. And thus adverse effects on the fluid flow can be reduced. In this example, the flow path component 77 is provided only on the umbrella member 76, but the present invention is not limited to this.

  In the above embodiment, the flow path component 13 includes the first side wall 13a on the rotation direction side in the flow path 11, the second side wall 13b on the counter rotation direction side in the flow path 11, the first side wall 13a, and the second side wall. Although it has the outer peripheral wall 13c which connects the radial direction outer sides with 13b, it is good also as a structure which has another wall.

  For example, as shown in FIG. 13, the flow path component 81 extends from the common (connected) radial inner end of the first and second side walls 82, 83 inward in the radial direction to rotate the flow passage 11. A configuration having a common wall 85 that also constitutes a part of the counter-rotation direction side wall surface (of the flow passage 11 adjacent in the circumferential direction) (not constituting the hollow portion 84) while constituting a part of the direction side wall surface. Good. In addition, the common wall 85 of this example has a reduced width portion 85a whose width is narrower toward the radially inner side (as viewed from the axial direction) on the radially inner side, and a constant width portion 85b having a constant width at the radially intermediate portion. And a widened portion 85c having a width that is wider toward the outer side in the radial direction. In this example (see FIG. 13), the floor portion 12 in the hollow portion 84 is provided with one reinforcing rib 86. The reinforcing ribs 86 extend radially outward from the mounting hole 12 a as a center and are connected to the first side wall 82 and the second side wall 83.

  In this way, for example, a large flow path 11 can be secured on the radially inner side where the space is narrow. Therefore, for example, the number of the flow paths 11 can be increased. Further, for example, since the (outer) area of the outer peripheral wall 88 can be reduced, friction (loss) with the fluid can be reduced, and the efficiency can be improved. In addition, for example, the radial length of the first side wall 82 and the second side wall 83 can be shortened, and the circumferential distance of the outer peripheral wall 88 can be shortened by narrowing the interval in the circumferential direction. It becomes difficult for the part 81 to bend (fall down), and it becomes possible to secure more strength. In this example, the number of flow path constituting portions 81 (flow passages 11) is eleven. Thereby, for example, it is possible to avoid the occurrence of a large vibration overlapping with the rotation order of the motor 1 as in the case where the number of the flow path constituting portions 13 is four as in the above embodiment.

  Further, for example, as in the reference example illustrated in FIG. 14, the common wall 85 of the above-described another example (see FIG. 13) may be provided but the reinforcing rib 86 may not be provided. That is, in this example, the radial length of the first side wall 82 and the second side wall 83 can be shortened, and the circumferential distance of the outer peripheral wall 88 can be shortened by narrowing the circumferential distance. The path constituting portion 81 is difficult to bend (fall down), and it is possible to ensure the strength even when the configuration is not provided with the reinforcing rib 86.

In the above embodiment, the reinforcing ribs 22 are integrally provided so as to be connected to the outer peripheral wall 13c. However, the present invention is not limited to this and may be changed to a shape not connected to the outer peripheral wall 13c.
In the above embodiment, the reinforcing ribs 22 that are integrally provided so as to be connected to the outer peripheral wall 13c extend radially outward from the mounting hole 12a (that is, the rotation axis center), but are not limited thereto. You may change into shapes other than radial shape, ie, the shape inclined with respect to the radial direction.

  In the above embodiment, the thick wall portion 12b is provided in the axial direction on the axial center side of the floor portion 12. However, the present invention is not limited to this, and for example, the axial thickness of the floor portion 12 is provided. May be the same on the radially outer side and the axial center side (the radially inner side).

  In the above embodiment, the axial height of the flow passage 11 is set such that the radially outer side is set lower than the axial center side, but is not limited to this, for example, the radially outer side and the axial center side (diameter (Inward direction) may be the same. In the above embodiment, the width of the flow passage 11 is set such that the radially outer side is set wider than the axial center side. However, the present invention is not limited to this, for example, the radial outer side and the axial center side (radial inner side) ) And the same.

  In the above embodiment, the first side wall 13a on the rotational direction side in the flow passage 11 has an involute curve-shaped involute portion 13d on the radially inner side when viewed from the axial direction, and an arc-shaped arc portion on the radially outer side. Although it has 13e, it is not limited to this, You may change to another curved shape, a linear shape, and the shape which combined them.

  In the above embodiment, the impeller 3 has the balance adjustment protrusions 31 and 32 that protrude in the axial direction and can be deleted. However, the present invention is not limited to this, and the impeller 3 does not have the balance adjustment protrusions 31 and 32. Also good.

  In the above embodiment, the motor 1 is a 4-pole 6-slot motor. However, the present invention is not limited to this. For example, the motor 1 may have a different number of magnetic poles or slots, such as an 8-pole 12-slot.

-In the above-mentioned embodiment, although four flow path composition parts 13 (flow passage 11) were used, it is not limited to this and may change into other numbers.
In the above embodiment, the side surfaces of the spiral chamber constituting grooves 6c and 7e are linear cross-section straight portions 6e and 7g along the axial direction (of the rotary shaft 9), but are not limited thereto. It may be a curved shape.

In the above embodiment, the centrifugal pump is an air pump, but is not limited thereto, and may be embodied as a centrifugal pump for other fluids such as liquid.
The technical idea that can be grasped from the above embodiment and other examples will be described below together with the effects thereof.

  (A) In the centrifugal pump according to any one of claims 1 to 6, the first side wall has an involute portion having an involute curve shape radially inward when viewed from the axial direction, and radially outward. A centrifugal pump having an arc-shaped arc portion.

  According to this configuration, the first side wall has an involute curve-shaped involute portion on the radially inner side and an arc-shaped arc portion on the radially outer side when viewed from the axial direction. The loss can be suppressed and the efficiency can be increased.

  (B) a centrifugal pump in which an impeller having a plurality of flow passages communicating an inner space at the center of the shaft and an outer space radially outside is disposed inside a pump case, the impeller A floor portion having an attachment hole to which the rotation shaft is fixed at the axial center; an umbrella portion provided with a fluid introduction hole at the axial center thereof so as to face the floor portion in the axial direction; the floor portion and the umbrella And a plurality of flow path components in the circumferential direction that constitute the flow passage together with the floor portion and the umbrella portion, and the flow path configuration portion is on the rotational direction side in the flow passage The first side wall, the second side wall on the counter-rotation direction side in the flow passage, the outer peripheral wall connecting the radially outer sides of the first side wall and the second side wall, the first side wall, and the second side wall. Extending radially inward from a common radially inner end of the side wall, Centrifugal pump characterized by having a common wall also constitutes a part of the counter-rotating direction side surface while constituting a part of the direction-side wall.

  According to this configuration, the flow path component includes the hollow portion surrounded by the first side wall, the second side wall, and the outer peripheral wall, so that the weight can be reduced. Moreover, since the flow path component has a common wall on the radially inner side, a large flow path can be secured on the radially inner side where the space is narrow. Therefore, for example, the number of flow paths can be increased. Further, for example, since the area of the outer peripheral wall can be reduced, the friction (loss) between the outer peripheral wall and the fluid can be reduced, and the efficiency can be improved. In addition, for example, the radial length of the first side wall and the second side wall can be shortened, and the circumferential distance of the outer peripheral wall can be shortened by narrowing the circumferential interval, so that the flow path component is bent. It becomes difficult to (fall down), and it is possible to ensure strength (even if the structure does not include a reinforcing rib).

  DESCRIPTION OF SYMBOLS 2 ... Pump case, 3 ... Impeller, 9 ... Rotating shaft, 11 ... Flow path, 12 ... Floor part, 12a ... Mounting hole, 12b ... Thick part, 13, 74, 77, 81 ... Flow path component, 13a , 82 ... 1st side wall, 13b, 83 ... 2nd side wall, 13c, 88 ... Outer peripheral wall, 15, 73, 76 ... Umbrella member (umbrella part), 15a ... Fluid introduction hole, 21, 84 ... Hollow part, 22, 86 ... reinforcing ribs, 85 ... common walls.

Claims (7)

A centrifugal pump in which an impeller having a plurality of flow passages communicating the inner space at the center of the shaft and the outer space radially outside is disposed inside the pump case,
The impeller has a floor portion having an attachment hole in which a rotation shaft is fixed at the center of the shaft, and an umbrella portion provided with a fluid introduction hole at the center of the shaft so as to face the floor portion in the axial direction; A plurality of flow path components in the circumferential direction that are arranged between the floor portion and the umbrella portion and constitute the flow passage together with the floor portion and the umbrella portion;
The flow path component includes a first side wall on the rotational direction side in the flow path, a second side wall on the counter-rotation direction side in the flow path, and radially outer sides of the first side wall and the second side wall. By having an outer peripheral wall to be connected, it has a hollow portion surrounded by them,
A centrifugal pump characterized in that a reinforcing rib is provided in the hollow portion. The centrifugal pump according to claim 1,
The centrifugal pump, wherein the reinforcing rib is provided so as to be connected to the outer peripheral wall. The centrifugal pump according to claim 2,
The centrifugal pump is characterized in that the reinforcing ribs extend radially around the mounting hole. The centrifugal pump according to any one of claims 1 to 3,
A centrifugal pump characterized in that a thick wall portion is provided in the axial direction on the axial center side of the floor portion. The centrifugal pump according to any one of claims 1 to 4,
The centrifugal pump according to claim 1, wherein the axial height of the flow passage is set lower on the radially outer side than on the axial center side. The centrifugal pump according to claim 5,
The centrifugal pump is characterized in that the width of the flow passage is set wider on the radially outer side than on the axial center side. The centrifugal pump according to any one of claims 1 to 6,
The flow path component extends radially inward from a common radial inner end of the first side wall and the second side wall to form a part of the rotational side wall surface of the flow passage, while facing the counter-rotating direction. A centrifugal pump having a common wall that also constitutes a part of a side surface.

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