JP2017172500A - Centrifugal Pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal pump capable of improving efficiency.SOLUTION: In a centrifugal pump, an impeller is disposed in the inside of a pump case, which includes a floor portion having an attaching hole to which a rotary shaft is fixed at its axis center, an umbrella portion 24 provided with a fluid introducing hole 24a at its axis center and provided so as to oppose to the floor portion in an axial direction, and a flow path structure portion provided between the floor portion and the umbrella portion 24. On an opposite surface of the umbrella portion 24 to the pump case, groove portions 31 intersecting a circumferential direction are provided in parallel in the circumferential direction, when viewed from the axial direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a centrifugal pump.

  Conventionally, as a centrifugal pump, a floor portion having a mounting 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; In some cases, an impeller (a so-called closed impeller) including a flow path component provided between a floor portion and an umbrella portion is disposed inside a pump case (see, for example, Patent Document 1).

JP 2004-278111 A

  However, in the centrifugal pump as described above, the fluid led out radially outward from the impeller during rotation flows back radially inward (fluid introduction hole side) through the gap between the umbrella portion and the pump case. As a result, the efficiency may be reduced.

  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 achieving high efficiency.

  A centrifugal pump that solves the above-described problem is provided with a floor portion having a mounting hole in which a rotation shaft is fixed at the center of the shaft, and a fluid introduction hole provided at the center of the shaft so as to face the floor portion in the axial direction. An impeller including an umbrella part and a flow path component provided between the floor part and the umbrella part is a centrifugal pump disposed inside a pump case, and the centrifugal pump includes: Grooves that intersect the circumferential direction as viewed in the axial direction are arranged in parallel on the opposing surface along the circumferential direction.

  According to this configuration, since the groove portion that intersects the circumferential direction when viewed from the axial direction is arranged in parallel along the circumferential direction on the surface of the umbrella portion facing the pump case, the inner surface of the groove portion during rotation When the fluid collides with the pump, the pressure in the gap between the groove (umbrella) and the pump case can be increased. Therefore, it can suppress that the fluid led out to the radial direction outer side from the impeller flows backward to the radial direction inner side (fluid introduction hole side) through the said gap part, and suppresses the fall of the output by a reverse flow. High efficiency can be achieved.

In the centrifugal pump, it is preferable that the groove portion is arranged in parallel on a concentric circle of the umbrella portion.
According to this configuration, since the groove portion is arranged in parallel on the concentric circle of the umbrella portion, the pressure in the gap portion between the pump case and the pump case can be increased at a certain radial position during rotation. Therefore, the back flow of the fluid can be further suppressed, and a reduction in output due to the back flow can be further suppressed, and higher efficiency can be achieved. Moreover, the balance of the rotating body including the impeller can be improved.

In the centrifugal pump, it is preferable that the groove portion has a shape opened in the rotation direction of the impeller when viewed from the axial direction.
According to this configuration, since the groove portion has an opening shape in the rotation direction of the impeller when viewed from the axial direction, the fluid is easily introduced into the groove portion during rotation, and the fluid easily collides with the inner surface of the groove portion. As a result, the pressure in the gap between the pump case and the pump case can be further increased. Therefore, the back flow of the fluid can be further suppressed, and a reduction in output due to the back flow can be further suppressed, and higher efficiency can be achieved.

In the centrifugal pump, it is preferable that the groove portion has a V shape opened in the rotation direction of the impeller when viewed from the axial direction.
According to this configuration, since the groove portion has a V shape opened in the rotation direction of the impeller when viewed from the axial direction, fluid is easily introduced into the groove portion during rotation, and the inner surface of the groove portion is counter-rotated. Since the fluid easily collides locally at the end portion in the direction, the pressure in the gap between the pump case can be locally increased at a part in the radial direction. Therefore, the back flow of the fluid can be further suppressed, and a reduction in output due to the back flow can be further suppressed, and higher efficiency can be achieved.

In the centrifugal pump, it is preferable that the depth of the groove is set to be equal to or less than half of the thickness of the umbrella.
According to this configuration, since the depth of the groove is set to be half or less of the thickness of the umbrella, the pressure in the gap between the pump case and the pump case can be increased while maintaining the strength of the umbrella.

In the centrifugal pump, it is preferable that the groove portion is provided on a radially outer side than a radial center position between an inner diameter of the fluid introduction hole and an outer diameter of the umbrella portion.
According to this configuration, the groove is provided on the radially outer side than the central position in the radial direction between the inner diameter of the fluid introduction hole and the outer diameter of the umbrella part. The fluid can collide with the inner surface of the groove at high speed, and the pressure in the gap with the pump case can be further increased. Therefore, the back flow of the fluid can be further suppressed, and a reduction in output due to the back flow can be further suppressed, and higher efficiency can be achieved.

In the centrifugal pump, it is preferable that the groove portion is provided on a radially inner side than an outer edge of the umbrella portion.
According to this configuration, since the groove portion is provided radially inward from the outer edge of the umbrella portion, it is possible to prevent the groove portion from disturbing the flow of the fluid on the radially outer side of the impeller during rotation. That is, if the groove portion reaches the outer edge of the umbrella portion, the opening on the radially outer side of the groove portion may cause disturbance in the fluid flow on the radially outer side of the impeller during rotation. Can do.

In the centrifugal pump, it is preferable that all the groove portions have the same shape.
According to the same structure, since all the groove parts are the same shape, the pressure in the gap part between the pump case can be increased in a well-balanced manner. Moreover, the balance of the rotating body including the impeller can be improved.

  In the centrifugal pump of the present invention, high efficiency can be achieved.

The partial sectional view of the centrifugal pump in one embodiment. Sectional drawing of the impeller in one Embodiment. The top view of the 2nd impeller member in one Embodiment. The partial expanded sectional view of the centrifugal pump in one Embodiment.

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.

  A center hole 4b is formed in the center of the bottom 4a (upper part in FIG. 1) of the motor case 4, and the base end side (the upper end in FIG. 1) of the rotary shaft 7 of the rotor 5b is inserted into the center hole 4b via a bearing 6. Side (bottom 4a side)) is supported. In addition, an annular sensor magnet 9 is attached to a base end portion (in FIG. 1, an upper end portion (end portion on the bottom portion 4a side)) of the rotating shaft 7 that protrudes outside the motor case 4 via a resin-made fixing ring 8. Is fixed. A circuit board 11 is fixed to the bottom 4 a of the motor case 4 via a fixing member 10. Various elements such as a rotation sensor 12 that detects rotation (rotation angle, rotation speed, etc.) of the rotating shaft 7 are mounted on the circuit board 11 so as to face the sensor magnet 9.

  The pump case 2 includes a first case 13 that is fixed so as to substantially close an 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 13. 14.

  A center hole 13 a is formed at the center of the first case 13, and the distal end side (the pump case 2 side) of the rotary shaft 7 is supported on the inner peripheral surface of the center hole 13 a via a bearing 15. A circular recess 13 b is formed on the end surface of the first case 13 on the second case 14 side as viewed from the axial direction of the rotary shaft 7. Further, a spiral chamber constituting groove 13c is formed on the outer peripheral side of the recess 13b on the end surface of the first case 13 on the second case 14 side.

  An air introduction hole 14 a is formed at the center of the second case 14. The air introduction hole 14a penetrates along the axial direction of the rotary shaft 7 and is formed so that its diameter decreases toward the motor 1 side (first case 13 side). In addition, a circular recess 14b is formed on the end surface of the second case 14 on the first case 13 side when viewed from the axial direction of the rotary shaft 7, and the recess 14b together with the recess 13b of the first case 13 is an impeller housing portion. H is constituted. Further, a spiral chamber constituting groove 14c is formed on the outer peripheral side of the concave portion 14b on the end surface of the second case 14 on the first case 13 side, and the spiral chamber constituting groove 14c together with the spiral chamber constituting groove 13c of the first case 13 is formed. A spiral chamber U is formed. In addition, an air discharge cylinder portion 14 d that communicates with the spiral chamber U on the radially outer side of the impeller housing portion H is formed in a part of the second case 14 in the circumferential direction.

  An annular seal groove 13d is formed on the mating surface of the first case 13 with the second case 14 at a position radially outside the spiral chamber U, and the second case 14 is aligned with the seal groove 13d. 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.

  In addition, a substantially bottomed cylindrical sealing case 16 that covers the entire motor 1 is fixed to the first case 13. The sealed case 16 has a flange portion 16a extending radially outward at an opening end portion thereof, and a plurality of locations (only one location shown in FIG. 1) of the flange portion 16a penetrates the flange portion 16a to form a first case. It is fixed by a screw 17 screwed to 13. An annular seal groove 13e is formed on the mating surface of the first case 13 with the flange portion 16a. The seal groove 13e accommodates a seal ring S2 that is crushed and clamped by the mating surface of the flange portion 16a. ing. Thereby, the leakage of the air from the mating surface of the first case 13 and the flange portion 16a is prevented. A wiring hole 16 c is formed in the bottom portion 16 b of the sealed case 16. A seal rubber member 19 is fitted into the wiring hole 16c to prevent air leakage from the wiring hole 16c while passing through the wiring 18. The wiring 18 electrically connects an external control device or power supply device to the circuit board 11 or the winding of the stator 5a.

  The impeller 3 is fixed so as to be rotatable integrally with the tip end portion (end portion on the pump case 2 side) of the rotating shaft 7 protruding into the impeller housing portion H, and is disposed in the impeller housing portion H. The impeller 3 has a plurality of flow passages 20 that communicate the inner space at the center of the shaft with the outer space (vortex chamber U) on the outer side in the radial direction, and the fluid introduced from the air introduction hole 14a by being rotated. As described above, the air is led out from the inner space side to the outer space (spiral chamber U) side through the flow passage 20, and as a result, air is injected from the air discharge cylinder portion 14d.

  Specifically, as shown in FIGS. 1 and 2, the impeller 3 includes a substantially disc-shaped floor portion 21 having an attachment hole 21 a to which the rotation shaft 7 is fixed at the axial center, and an axial direction from the floor portion 21. A first impeller member 23 having a plurality (11 in the present embodiment) of intermediate blade portions 22 in a circumferential direction provided extending in the direction is provided. The floor 21 is formed in a substantially disc shape with the rotation axis center X as the center.

  Further, as shown in FIG. 1, the impeller 3 is provided with a fluid introduction hole 24a at the axial center thereof, and a substantially disc-shaped umbrella portion 24 provided so as to face the floor portion 21 in the axial direction, A second impeller member 26 having a plurality of (11 in this embodiment) blade portions 25 in the circumferential direction provided extending from the umbrella portion 24 in the axial direction is provided. In the present embodiment, the intermediate blade portion 22 and the blade portion 25 constitute a flow path constituting portion. The umbrella part 24 of this embodiment is formed so that it may approach the floor part 21 as it goes to radial direction outer side (external space side) from radial direction inner side (internal space side). Moreover, the umbrella part 24 is formed in a substantially disk shape with the rotation axis center X as the center.

  Specifically, the blade portion 25 is erected from the umbrella portion 24 and is disposed between the umbrella portion 24 and the floor portion 21. Further, the blade portion 25 is formed to extend in the radial direction from the fluid introduction hole 24 a of the umbrella portion 24 to the outer edge of the umbrella portion 24 while curving in the counter-rotation direction side toward the radially outer side. Moreover, the blade | wing part 25 is formed so that a width | variety may become small, so that it goes to an edge part only in both radial direction both ends, and the width | variety is constant in the intermediate part (except radial direction both ends).

  Further, the intermediate blade portion 22 is erected from the floor portion 21 and is disposed between the blade portions 25 (see FIG. 2) between the floor portion 21 and the umbrella portion 24, and circulates together with the blade portion 25. A path 20 is configured. Further, the intermediate vane portion 22 has its own radially inner end on the radially outer side than the radially inner end of the vane portion 25, thereby allowing a flow path between the radially inner ends of the vane portion 25. 20 passage cross-sectional areas are provided without being reduced. Further, the intermediate blade portion 22 is formed in its entirety so as to extend radially to the outer edge of the floor portion 21 while curving in the counter-rotation direction side toward the radially outer side, and to increase in width toward the radially outer side. Has been.

  As shown in FIGS. 3 and 4, a groove portion 31 that intersects the circumferential direction when viewed from the axial direction is formed on the surface of the umbrella portion 24 facing the pump case 2 (second case 14) in the circumferential direction. Are arranged side by side.

  Specifically, as shown in FIG. 3, the groove portion 31 of the present embodiment is equiangular (this embodiment is a position where the radial position (distance) from the rotational axis center X is equal) on the concentric circle A of the umbrella portion 24. 72 at an interval of 5 °). In addition, the grooves 31 have the same shape as viewed from the axial direction and have a shape opened in the rotation direction of the impeller 3. In this embodiment, the groove portion 31 has a V-shape (so-called herringbone) opened in the rotation direction. Shape). In the present embodiment, the angle formed by the V-shape of the groove 31 is set to 90 °. Further, the groove 31 is provided on the outer side in the radial direction than the central position B in the radial direction between the inner diameter of the fluid introduction hole 24 a and the outer diameter of the umbrella part 24. The groove portion 31 is provided on the radially inner side with respect to the outer edge of the umbrella portion 24.

Also, as shown in FIG. 4, the depth C1 of the groove 31 is less than half of the thickness C2 of the umbrella 24, and in this embodiment is set to about 1/3 of the thickness C2 of the umbrella 24. Yes.
Next, the operation of the centrifugal pump configured as described above will be described.

  When power is supplied to the motor 1, the rotor 5 b is driven to rotate, and the impeller 3 is rotated together with the rotor 5 b (rotating shaft 7) about the rotation axis center X. Then, air is introduced into the inner space at the axial center of the impeller 3 through the air introduction hole 14a of the pump case 2, and the outer space on the radially outer side of the impeller 3 through the flow path 20 from the inner space side. 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 14 d of the pump case 2.

Next, the characteristic effects of the above embodiment will be described below.
(1) Since the groove portion 31 that intersects the circumferential direction when viewed from the axial direction is arranged along the circumferential direction on the surface of the umbrella portion 24 facing the pump case 2, When the air as the fluid collides with the side surface, the pressure in the gap 32 (see FIG. 4) between the groove 31 (umbrella 24) and the pump case 2 can be increased. Therefore, it can suppress that the air led out from the impeller 3 to the spiral chamber U radially outside flows backward to the radially inner side (fluid introduction hole 24a side) via the gap portion 32. It is possible to increase the efficiency by suppressing the decrease in the output due to.

  (2) Since the groove portion 31 is arranged side by side on the concentric circle A of the umbrella portion 24, the pressure in the gap portion 32 between the groove portion 31 (umbrella portion 24) and the pump case 2 is constant throughout the circumferential direction during rotation. It is possible to increase the position in the radial direction, and the backflow of air can be further suppressed. Moreover, the balance of the rotating body including the impeller 3 can be made favorable.

  (3) Since the groove portion 31 has a shape opened in the rotation direction of the impeller 3 when viewed from the axial direction, air is easily introduced into the groove portion 31 during rotation, and the air collides with the inner surface of the groove portion 31. By becoming easy, the pressure in the gap | interval part 32 between the groove part 31 (umbrella part 24) and the pump case 2 can be raised more. Therefore, the backflow of air can be further suppressed, and the reduction in output due to the backflow can be further suppressed to achieve higher efficiency.

  (4) Since the groove portion 31 is V-shaped when viewed from the axial direction and opened in the rotation direction of the impeller 3, air can be easily introduced into the groove portion 31 during rotation, and the inner surface of the groove portion 31 is counteracted. A part of the radial direction of the pressure in the gap portion 32 between the groove portion 31 (umbrella portion 24) and the pump case 2 because air easily collides locally at the end portion (V-shaped corner portion) in the rotation direction. Can be increased locally. Therefore, the backflow of air can be further suppressed, and the reduction in output due to the backflow can be further suppressed to achieve higher efficiency.

  (5) Since the depth C1 of the groove part 31 is set to be less than half of the thickness C2 of the umbrella part 24 (in this embodiment, about 1/3 of the thickness C2 of the umbrella part 24), the strength of the umbrella part 24 The pressure in the gap portion 32 between the groove portion 31 (umbrella portion 24) and the pump case 2 can be increased.

  (6) Since the groove portion 31 is provided on the radially outer side from the central position B in the radial direction between the inner diameter of the fluid introduction hole 24a and the outer diameter of the umbrella portion 24, the groove portion 31 is rotated as compared with the case where the groove portion 31 is provided on the radially inner side. Sometimes air can collide with the inner surface of the groove 31 at a high speed, and the pressure in the gap 32 between the groove 31 (umbrella 24) and the pump case 2 can be further increased. Therefore, the backflow of air can be further suppressed, and the reduction in output due to the backflow can be further suppressed to achieve higher efficiency.

  (7) Since the groove portion 31 is provided radially inward of the outer edge of the umbrella portion 24 (not opened radially outward), the groove portion 31 is located on the radially outer side (the spiral chamber U) of the impeller 3 when rotating. It is possible to prevent the air flow from being disturbed. That is, when the groove portion 31 reaches the outer edge of the umbrella portion 24 (the outer edge of the umbrella portion 24 and the groove portion 31 communicate with each other), the radially outer opening of the groove portion rotates in the radially outer air of the impeller 3 during rotation. Although there is a risk of causing disturbance in the flow, it can be avoided.

  (8) Since all the groove parts 31 are the same shape, the pressure in the gap part 32 between the groove part 31 (umbrella part 24) and the pump case 2 can be increased with a good balance. Moreover, the balance of the rotating body including the impeller 3 can be made favorable.

  (9) Since the groove portions 31 are arranged side by side at equal angular intervals (5 ° in this embodiment), the groove portion 31 (umbrella portion 24) and the pump case 2 are maintained while maintaining the balance of the rotating body including the impeller 3. The pressure in the gap 32 between the two can be increased.

The above embodiment may be modified as follows.
In the above embodiment, the groove portion 31 has a shape that opens in the rotation direction of the impeller 3 as viewed from the axial direction, and has a V shape that opens in the rotation direction. As long as it intersects with the circumferential direction and air collides with its inner surface during rotation and the pressure in the gap portion 32 can be increased, the shape may be changed to another shape. For example, the groove portion may have a U shape that opens in the rotation direction of the impeller 3. Further, for example, the groove portion may have a linear shape inclined with respect to the circumferential direction, such as a shape along the radial direction. Further, for example, the groove portions may be linearly inclined with respect to the circumferential direction and arranged in parallel (connected) in a zigzag manner along the circumferential direction. In the above embodiment, the angle formed by the V-shape of the groove 31 is set to 90 °, but it may be a V-shape having an angle other than 90 °.

-In above-mentioned embodiment, although the groove part 31 was arranged in parallel on the concentric circle A of the umbrella part 24, it is not limited to this, A several groove part may be provided in the position where radial directions differ.
-In the said embodiment, although the depth C1 of the groove part 31 was below half of the thickness C2 of the umbrella part 24, and was set to about 1/3 of the thickness C2 of the umbrella part 24, it is to this, For example, the thickness may be larger than half of the thickness C2 of the umbrella portion 24.

  In the above embodiment, the groove 31 is provided on the radially outer side than the central position B in the radial direction between the inner diameter of the fluid introduction hole 24a and the outer diameter of the umbrella part 24. You may provide in the radial inside rather than the center position B.

  In the above embodiment, the groove 31 is provided on the radially inner side of the outer edge of the umbrella part 24 (not open to the outer side in the radial direction), but is not limited thereto, and reaches the outer edge of the umbrella part 24. It is good also as a structure (opening to radial direction outer side).

-In above-mentioned embodiment, although all the groove parts 31 were having the same shape, it is not limited to this, You may arrange in parallel the groove part of a different shape along the circumferential direction.
In the above embodiment, the flow path component that is provided between the floor portion 21 and the umbrella portion 24 and configures the flow passage 20 is the vane portion 25 and the intermediate vane portion 22. If the internal space at the center of the shaft of the vehicle 3 and the external space (vortex chamber U) on the outer side in the radial direction communicate with each other and fluid can be led out to the spiral chamber U during rotation, the shape may be changed to another shape.

In the above embodiment, 72 groove portions 31 are arranged in parallel at equiangular (5 °) intervals, but the present invention is not limited thereto, and may be non-equal angular intervals, or may be changed to other numbers. May be.
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 embodiment, the umbrella portion 24 is formed so as to approach the floor portion 21 as it goes from the radially inner side to the radially outer side. However, the present invention is not limited to this. You may form so that it may become parallel to 21.

  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.

  DESCRIPTION OF SYMBOLS 2 ... Pump case, 3 ... Impeller, 7 ... Rotating shaft, 21 ... Floor part, 21a ... Mounting hole, 22 ... Middle blade | wing part (flow-path structure part), 24 ... Umbrella part, 24a ... Fluid introduction hole, 25 ... Blade part (flow path constituent part), 31 ... groove part, A ... concentric circle, B ... radial center position, C1 ... depth of groove part, C2 ... thickness of umbrella part.

Claims (8)

A floor portion having an attachment hole to which the rotation shaft is fixed at the axial center; a umbrella portion provided with a fluid introduction hole at the axial center and facing the floor portion in the axial direction; the floor portion; An impeller including a flow path component provided between the umbrella part and the centrifugal pump disposed inside the pump case,
A centrifugal pump characterized in that grooves facing each other in the circumferential direction as viewed in the axial direction are arranged in parallel along the circumferential direction on the surface of the umbrella portion facing the pump case. The centrifugal pump according to claim 1,
The centrifugal pump according to claim 1, wherein the groove portion is arranged side by side on a concentric circle of the umbrella portion. The centrifugal pump according to claim 1 or 2,
The groove portion has a shape opened in the rotational direction of the impeller when viewed from the axial direction. The centrifugal pump according to claim 3, wherein
The groove portion has a V-shape opened in the rotation direction of the impeller when viewed from the axial direction. The centrifugal pump according to any one of claims 1 to 4,
The depth of the said groove part was set to half or less of the thickness of the said umbrella part, The centrifugal pump characterized by the above-mentioned. The centrifugal pump according to any one of claims 1 to 5,
The centrifugal pump according to claim 1, wherein the groove portion is provided radially outside a central position in a radial direction between an inner diameter of the fluid introduction hole and an outer diameter of the umbrella portion. The centrifugal pump according to any one of claims 1 to 6,
The centrifugal pump according to claim 1, wherein the groove is provided radially inward from an outer edge of the umbrella. The centrifugal pump according to any one of claims 1 to 7,
All the said groove parts are the same shapes, The centrifugal pump characterized by the above-mentioned.

Images