JP2020060115A - Liquid feed pump - Google Patents

Abstract

To provide a liquid feed pump capable of forming smooth flow of fluid inside the pump to improve pump efficiency.SOLUTION: A liquid feed pump 1 is configured such that a centrifugal impeller 11 and a centripetal impeller 15 are alternately arranged integrally, a rotational shaft is fixed to the centrifugal impeller 11 and the centripetal impeller 15, and the centrifugal impeller 11 and the centripetal impeller 15 are housed in a pump housing 18 in which a flow passage is formed. In the liquid feed pump 1, the centripetal impeller 15 has a diameter larger than that of the centrifugal impeller 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid delivery pump. The present invention particularly relates to a multistage spiral type liquid delivery pump for delivering a fluid such as a cooling fluid for an automobile.

  Conventionally, there is a liquid feed pump in which a plurality of stages of impellers are arranged on the rotary shaft along the axial direction of the rotary shaft. In the liquid feed pump, the fluid sucked from the suction port of the casing is pressurized by the first-stage centripetal impeller and the centrifugal impeller, and the pressurized fluid is passed through the return flow passage to the second-stage centripetal impeller and It is configured so that it can be repeated multiple times by being sent to the centrifugal impeller and further boosted in pressure. Such a liquid feed pump in which centrifugal impellers are arranged on the rotating shaft in a plurality of stages is known (see, for example, Patent Document 1).

  In the liquid feed pump of Patent Document 1, a suction port is formed at one end side in the axial direction of the outer peripheral portion of the casing formed in a substantially cylindrical shape, and a discharge port is formed at the other end side in the axial direction of the outer peripheral portion. A plurality of centripetal impellers and centrifugal impellers are alternately rotatably provided in the casing. The centripetal impeller and the centrifugal impeller are integrally arranged with the core plate and the side plate of the adjacent impeller in common, and the rotary shafts are fixed to both ends of the entire impeller unit and flowed inward. The entire impeller section is housed in a casing that forms a passage.

  The fluid flowing in from the suction port enters from the outer diameter side of the centripetal impeller and is sent to the inner diameter side of the centripetal impeller to be pressurized. The fluid sent to the inner diameter side enters from the inner diameter side of the centrifugal impeller of the next stage and is further pressurized by being sent to the outer diameter side of the centrifugal impeller. The fluid sent to the outer diameter side is sent to the centripetal impeller of the next stage through the return flow path, and is repeatedly sent from the centrifugal impeller of the next stage. In this way, the fluid whose pressure has been repeatedly increased by the centripetal impeller and the centrifugal impeller is delivered from the discharge port.

JP-A-55-96394

  By the way, it is preferable that the fluid entering from the suction port of the liquid feed pump is smoothly pressurized in the flow passage inside the liquid feed pump and sent out from the discharge port, but the centripetal impeller counters the centrifugal force of the fluid. Since the fluid is moved (centered) to the inner diameter side, it is difficult to smoothly flow the fluid and raise the pressure without backflowing.

  However, in the liquid delivery pump of Patent Document 1, the centripetal impeller and the centrifugal impeller are arranged on the front and back of a common core plate so as to have the same diameter. For this reason, the centripetal impeller that moves the fluid against the centrifugal force of the fluid has a lower delivery capacity compared to the centrifugal impeller installed side by side, and the fluid delivered from the centrifugal impeller can be smoothly converted into the centripetal impeller. Since it cannot flow, the pump efficiency of the liquid delivery pump as a whole decreases.

  An object of the present invention is to provide a liquid delivery pump capable of improving the pump efficiency by forming a smooth flow of fluid inside the pump in view of the problems of the prior art.

[1] The liquid delivery pump according to the present invention is
A liquid feed pump in which a centrifugal impeller and a centripetal impeller are alternately fixed to a rotating shaft, and the centrifugal impeller and the centripetal impeller are rotatably housed in a pump housing in which a fluid flow path is formed. ,
A diameter of the centripetal impeller is larger than a diameter of the centrifugal impeller.

  According to this structure, the centrifugal impeller and the centripetal impeller are alternately fixed to the rotating shaft in the pump housing, and the diameter of the centripetal impeller is larger than the diameter of the centrifugal impeller. In the centripetal impeller, the fluid moves toward the inner diameter side against the centrifugal force. Therefore, the total force of the centripetal impeller that delivers the fluid is obtained by subtracting (the force of the centrifugal force that causes the fluid to flow backward) from (the force of scraping the fluid by the centripetal impeller and moving it toward the inner diameter side along the blade shape). It will be a minute. On the other hand, the total force of the centrifugal impeller for delivering the fluid is equal to (force for moving the fluid by the centrifugal impeller to the outer diameter side) plus (force for moving the fluid by the centrifugal force to the outer diameter side). If the diameter of the centripetal impeller and the diameter of the centrifugal impeller are made equal, the total force of the centripetal impeller to deliver the fluid will be lower than that of the centrifugal impeller, and the fluid delivered from the centrifugal impeller will be smooth to the centripetal impeller. There is a risk that some of the fluid may flow back.

  In this respect, in the present invention, since the diameter of the centripetal impeller is larger than the diameter of the centrifugal impeller (has a high head), (the force of scraping the fluid by the centripetal impeller and moving it toward the inner diameter side along the blade shape) ) Can be increased, and the total force of the centripetal impeller for delivering fluid can be made equal to the total force of the centrifugal impeller for delivering fluid. As a result, the fluid delivered from the centrifugal impeller smoothly flows to the centripetal impeller, and a smooth flow of the fluid inside the pump is formed, so that pump efficiency can be improved. Further, the fluid discharged (discharged) from the centrifugal impeller needs to change its direction by 180 degrees and enter from the outer edge of the centripetal impeller in the centripetal direction. In the present invention, the centripetal impeller has a diameter of the centrifugal impeller. Since the diameter is larger than the diameter of the centripetal impeller, the fluid can be actively scraped at the outer edge of the centripetal impeller, and the fluid can change its direction by 180 degrees to compensate for entering the centripetal direction from the outer edge of the centripetal impeller. .

[2] Further, in the liquid delivery pump of the present invention,
A housing opening is formed in the pump housing substantially coaxially with the rotation shaft, and the centrifugal impeller is arranged so as to face the housing opening.
A delivery space is provided between the inner wall surface of the pump housing and the centrifugal impeller so that the fluid flowing from the housing opening flows from the centrifugal impeller toward the centripetal impeller. preferable.

  With this configuration, in the liquid feed pump, the housing opening, the centrifugal impeller, and the centripetal impeller are arranged in this order along the axis of the rotating shaft. Therefore, the fluid can be efficiently sucked into the centrifugal impeller from the housing opening on the axis.

[3] Also, in the liquid delivery pump of the present invention,
The delivery space is
It is preferably larger than the suction space communicating with the delivery space between the inner wall surface and the centripetal impeller in the centrifugal direction.

  According to this structure, the delivery space on the centrifugal impeller side is larger than the suction space on the centripetal impeller side. The fluid delivered from the centrifugal impeller is delivered to the delivery space at a constant flow velocity and has a constant dynamic pressure. When the fluid in the delivery space moves from the delivery space to the suction space, it turns the direction by 180 ° and enters the centripetal impeller from its centrifugal direction. For this reason, when the flow velocity of the fluid sent from the centrifugal impeller is high (the dynamic pressure is high), the fluid loss of the fluid during turning is large.

  In this respect, in the present invention, since the delivery space on the centrifugal impeller side is larger than the suction space on the centripetal impeller side, the fluid delivered from the centrifugal impeller is decelerated in the delivery space to lower the dynamic pressure of the fluid and reduce the static pressure. The pressure can be increased. As a result, it is possible to suppress the hydrodynamic loss at the time of turning of the fluid sent from the centrifugal impeller and improve the pump efficiency.

[4] In the liquid delivery pump of the present invention,
A plurality of the pump housings are arranged so as to be stacked along the axial direction of the rotating shaft,
It is preferable that the plurality of pump housings are communicated with each other through the housing opening so that the fluid delivered from the delivery space flows from the centripetal impeller toward the centrifugal impeller.

  With this configuration, the fluid can be efficiently sucked from the centripetal impeller on the axis to the centrifugal impeller.

[5] In the liquid delivery pump of the present invention,
The pump housing is surrounded by an outer casing,
A fluid suction portion is formed on one end side of the outer casing,
It is preferable that the fluid suction part is arranged so as to face the housing opening so that the fluid flowing from the fluid suction part flows toward the centrifugal impeller.

  With this configuration, in the liquid delivery pump, the fluid suction portion, the housing opening portion, the centrifugal impeller, and the centripetal impeller are arranged in this order along the axis of the rotating shaft. Therefore, the fluid can be efficiently sucked into the centrifugal impeller from the housing opening on the axis.

[6] Further, in the liquid delivery pump of the present invention,
It is preferable that the centripetal impeller has a notch or a hole formed at a position larger than the diameter of the centrifugal impeller.

  With this configuration, the fluid delivered from the centrifugal impeller can be positively delivered to the centripetal impeller through the notch or the hole.

[7] In the liquid delivery pump of the present invention,
It is preferable that the centripetal impeller has a propeller portion cut and raised in a rotational direction at a position larger than a diameter of the centrifugal impeller.

  According to this structure, the fluid sent from the centrifugal impeller can be positively scraped and sent to the centripetal impeller side by the propeller portion.

FIG. 1 is a sectional view showing the structure of a liquid feed pump according to the present invention. 2A is a sectional view taken along line 2A-2A of FIG. FIG. 2B is an enlarged view of a main part showing another aspect of the centripetal impeller. FIG. 3 is a sectional view taken along line 3-3 of FIG. FIG. 4A is a cross-sectional view illustrating the operation of the liquid delivery pump according to the present invention. FIG. 4B is a cross-sectional view illustrating the operation of the centrifugal impeller of FIG. 4A. FIG. 4C is a cross-sectional view illustrating the operation of the centripetal impeller of FIG. 4A.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the liquid feed pump 1 is conceptually (schematically) shown.

  As shown in FIG. 1, a liquid delivery pump 1 according to an embodiment of the present invention is, for example, a pump for an automobile, and includes a first pump stage 10, a second pump stage 20, and a third pump stage. 30, an outer casing 40, an intermediate casing 50, a rotating shaft 60, and a drive device 70.

  The first pump stage 10, the second pump stage 20, and the third pump stage 30 are provided on the rotating shaft 60 in this order, and accelerate and deliver the fluid. The outer casing 40 encloses the first pump stage 10, the second pump stage 20 and the third pump stage 30. The intermediate casing 50 is disposed below the third pump stage 30, and is a fluid delivery unit that delivers the fluid accelerated by the first pump stage 10, the second pump stage 20, and the third pump stage 30 to the outside. It is equipped with 51. The drive device 70 drives the rotary shaft 60 and is connected to the intermediate casing 50.

  Next, the first pump stage 10 will be described. 2A shows a cross section of the centrifugal impeller 11 part, and FIG. 3 shows a cross section of the centripetal impeller 15 part. As shown in FIGS. 1 to 3, the first pump stage 10 includes a centrifugal impeller 11, a centripetal impeller 15, and a pump housing 18. The centrifugal impeller 11 and the centripetal impeller 15 are fixed to the rotating shaft 60, and the centrifugal impeller 11 and the centripetal impeller 15 are alternately arranged integrally.

  The pump housing 18 is a tubular member that surrounds the centrifugal side and the axially one end side of the centrifugal impeller 11 and the centripetal impeller 15, and the housing is provided at the center of the surface (upper surface) on the outer casing 40 side, which will be described later. The opening 18a is formed.

  In the centrifugal impeller 11, six centrifugal blades 13 having a spiral shape in a plan view are equally arranged on a disk-shaped centrifugal main plate 12, and the opposite side of the centrifugal main plate 12 of the centrifugal blade 13 has a disk shape. It is a so-called closed impeller covered with the side plate 14. An opening 14a for sucking fluid is formed in the center of the side plate 14.

In the centripetal impeller 15, six centripetal blades 17 which are spiral in a plan view are equally arranged on a disc-shaped centripetal main plate 16. The centripetal blade 17 is formed in a wall shape standing from the centripetal main plate 16 toward the pump housing 28 of the second pump stage 20, and the end portion of the centripetal blade 17 opposite to the centripetal main plate 16 is the second pump. It extends to the vicinity of the pump housing 28 of the step 20.
The centrifugal blade 13 and the centripetal blade 17 have a curved shape that is curved in a radial direction and spirally from the central portion toward the peripheral end portion in a plan view.

  The centrifugal impeller 11 and the centripetal impeller 15 have the spiral directions of the centrifugal impeller 13 and the centripetal impeller 17 opposite to each other when viewed from the tip end direction of the rotating shaft 60. Thus, when the centrifugal impeller 11 and the centripetal impeller fixed to the same rotating shaft 60 rotate in the same direction, the fluid is delivered in the centrifugal direction in the centrifugal impeller 11 and the fluid is scraped in the centripetal impeller 15. To be

  The diameter D2 of the centripetal impeller 15 is set to be larger than the diameter D1 of the centrifugal impeller 11. The delivery space S1 between the inner wall surface 19 of the pump housing 18 and the centrifugal impeller 11 in the centrifugal direction of the centrifugal impeller 11 is defined by the inner wall surface 19 and the centripetal impeller 15 that communicate with the delivery space S1 in the centrifugal direction. It is larger than the suction space S2 between them.

  Next, another mode of the centripetal wheel 15 will be described. As shown in FIG. 2B, the centripetal impeller 15 has at least a notch 16 a, a hole 16 b, or a propeller portion 16 c cut and raised in the rotational direction at a position larger than the diameter of the centrifugal impeller 11 of the centripetal main plate 16. One is formed.

  Next, the second pump stage 20 will be described. As shown in FIGS. 1 to 3, the second pump stage 20 includes a centrifugal impeller 21, a centripetal impeller 25, and a pump housing 28, and has the same configuration as the first pump stage 10. is there.

  The pump housing 28 is a cylindrical member that surrounds the centrifugal impeller 21 and the centripetal impeller 25 on the centrifugal direction side and the first pump stage 10 side, and the center of the surface on the first pump stage 10 side. A housing opening 28a is formed in the.

  The centrifugal impeller 21 includes a centrifugal main plate 22, six centrifugal blades 23, and side plates 24. An opening 24a for sucking fluid is formed in the center of the side plate 24.

  The centripetal impeller 25 includes a centripetal main plate 26 and six centripetal blades 27. The centripetal blade 27 extends from the centripetal main plate 26 to the vicinity of the pump housing 38 of the third pump stage 30.

  The diameter of the centripetal impeller 25 is larger than the diameter of the centrifugal impeller 21. The delivery space between the inner wall surface of the pump housing 28 and the centrifugal impeller 21 in the centrifugal direction of the centrifugal impeller 21 is the suction space between the inner wall surface in the centrifugal direction and the centripetal impeller 25 that communicate with the delivery space. Greater than.

  Next, the third pump stage 30 will be described. The third pump stage 30 includes a centrifugal impeller 31 and a pump housing 38, and has the same configuration as the centrifugal impeller 11 and the pump housing 18 of the first pump stage 10.

  The pump housing 38 is a tubular member that surrounds the centrifugal direction side of the centrifugal impeller 31 and the second pump stage 20 side, and has a housing opening 38a at the center of the surface on the second pump stage 20 side. It is formed and the surface on the centrifugal direction side is partially opened.

  The centrifugal impeller 31 includes a centrifugal main plate 32, six centrifugal blades 33, and side plates 34. An opening 34a for sucking fluid is formed in the center of the side plate 34.

  Next, the outer casing 40 will be described. The outer casing 40 surrounds the pump housings 18, 28 and 38, and includes a fluid suction portion 41 that sucks fluid from the outside. The fluid suction part 41 is formed on one end side in the axial direction of the outer casing 40 and opens substantially coaxially in the tip direction of the rotary shaft 60. The outer casing 40 also includes a bottom portion 42 that surrounds the lower side of the third pump stage 30. The bottom portion 42 has a generally mortar shape, the center of the mortar shape is open, and the rotating shaft 60 penetrates through this opening.

  The housing opening 18a of the pump housing 18 of the first pump stage 10 is arranged so as to face the fluid suction portion 41, and the fluid that flows from the fluid suction portion 41 into the pump housing 18 through the housing opening 18a. Centrifugal impellers 11 and centripetal impellers 15 are alternately arranged in the pump housing 18 so that the gas flows from the centrifugal impeller 11 toward the centripetal impeller 15.

  A pump housing 28 is connected below the first pump stage 10 so as to be coaxially stacked with the pump housing 18, whereby the pump housing 28 is delivered from the centripetal impeller 15 of the first pump stage 10. The housing opening 28a of the pump housing 28 is arranged so as to face the centripetal impeller 15 so that the fluid flowing into the centrifuge impeller 15 flows toward the centrifugal impeller 21.

  The centrifugal impeller 21 and the centripetal impeller 25 are alternately arranged so that the fluid flowing into the pump housing 28 from the housing opening 28 a flows into the pump housing 28 from the centrifugal impeller 21 toward the centripetal impeller 25. It is arranged.

  A pump housing 38 is connected below the second pump stage 20 so as to be coaxially stacked with the pump housing 28, whereby the pump housing 38 is delivered from the centripetal impeller 25 of the second pump stage 20 and is pumped inside the pump housing 38. The housing opening 38a of the pump housing 38 is arranged so as to face the centripetal impeller 25 so that the fluid flowing into the centripetal impeller 25 flows toward the centrifugal impeller 31.

  Next, the intermediate casing 50 will be described. The intermediate casing 50 is arranged between the bottom portion 42 of the outer casing 40 and the drive device 70. The intermediate casing 50 has an opening at the center of the main body, and a bearing 78 that supports the rotating shaft 60 is provided in this opening, and a shaft sealing device 79 that seals between the rotating shaft and the intermediate casing 50. There is. Further, a part of the pump housing 38 of the third pump stage 30 in the centrifugal direction is opened, and a fluid delivery portion 51 extending from the main body portion of the intermediate casing 50 is formed so as to face the opening. .

  Next, the drive device 70 will be described. The drive device 70 is a brushless motor having a stator and a rotor, and the stator side includes a motor housing 71, a coil support portion 72 provided in the motor housing 71, and a coil 73 supported by the coil support portion 72. I have it. In addition, a substrate support portion 75 is provided on the bottom of the motor housing 71, and a substrate 76 on which an electronic circuit (not shown) that controls power supply to the coil 73 is formed is provided on the substrate support portion 75. The rotor side of the drive device 70 is provided with a rotating shaft 60 rotatably supported by a bearing 77 provided on the substrate supporting portion 75 and a bearing 78 provided on the intermediate casing 50, and the rotating shaft 60. And a magnet 74. A rectification cap 61 is provided at the tip of the rotary shaft 60 to rectify the fluid sucked into the pump from the fluid suction portion 41.

  Next, the operation of the liquid feed pump 1 described above will be described. As shown in FIGS. 4A to 4C, the fluid is sucked into the pump from the fluid suction portion 41 of the liquid feed pump 1 as indicated by an arrow (1). The sucked fluid is rectified by the rectification cap 61 and sent to the centrifugal impeller 11 from the housing opening 18a of the first pump stage 10 as shown by the arrow (2) to be pressurized. The fluid whose pressure has been increased is delivered to the delivery space S1 as indicated by an arrow (3). Since the delivery space S1 on the centrifugal impeller 11 side is larger than the suction space S2 on the centripetal impeller 15 side, the fluid delivered from the centrifugal impeller 11 is decelerated in the delivery space S1, and the dynamic pressure of the fluid is reduced to a static pressure. Will increase.

  Therefore, the fluid in the delivery space S1 smoothly turns around as shown by the arrow (4), flows into the suction space S2, and is delivered to the centripetal wheel 15. The fluid sent to the centripetal impeller 15 is pressurized by the centripetal impeller 15 and is sent to the housing opening 28a of the second pump stage 20 as indicated by the arrow (5). The fluid sent to the second pump stage 20 is boosted in the same manner as the first pump stage 10 and sent to the housing opening portion 38 a of the third pump stage 30.

  The fluid sent to the third pump stage 30 is sent out from the centrifugal impeller 31 as shown by an arrow (6), and further sent out from the fluid sending section 51 as shown by an arrow (7).

  As described above, according to the present embodiment, the diameters of the centripetal impellers 15 and 25 are larger than the diameters of the centrifugal impellers 11 and 21. In the centripetal impellers 15 and 25, the fluid moves toward the inner diameter side against the centrifugal force. Therefore, the total force of the centripetal impellers 15 and 25 for delivering the fluid is equal to (the force of moving the fluid to the inner diameter side by the centripetal impellers 15 and 25) minus the force of the centrifugal force causing the fluid to flow backward. Become. On the other hand, the total force of the centrifugal impellers 11 and 21 for delivering the fluid is (force for moving the fluid by the centrifugal impellers 11, 21 to the outer diameter side) (force for moving the fluid by the centrifugal force to the outer diameter side). It will be the added amount. If the diameter of the centripetal impeller and the diameter of the centrifugal impeller are made equal, the total force of the centripetal impeller to deliver the fluid will be lower than that of the centrifugal impeller, and the fluid delivered from the centrifugal impeller will be smooth to the centripetal impeller. There is a risk that some of the fluid may flow back.

  In this respect, in the present embodiment, the diameters of the centripetal impellers 15 and 25 are larger than the diameters of the centrifugal impellers 11 and 21 (become a high head), so that (the fluid is scraped by the centripetal impeller to follow the blade shape). Therefore, the total force of the centripetal impellers 15 and 25 for delivering the fluid can be made equal to the total force of the centrifugal impellers 11 and 21 for delivering the fluid. As a result, the fluid sent out from the centrifugal impellers 11 and 21 smoothly flows to the centripetal impellers 15 and 25, and the smooth flow of the fluid inside the pump is formed to improve the pump efficiency. Further, the fluid discharged (discharged) from the centrifugal impellers 11 and 21 needs to change its direction by 180 degrees and enter from the outer edges of the centripetal impellers 15 and 25 in the centripetal direction. Since the diameter D2 of 15 and 25 is larger than the diameter D1 of the centrifugal impellers 11 and 21, the fluid is positively scraped by the outer edges of the centripetal impellers 15 and 25, and the fluid changes its direction by 180 degrees. It is possible to supplement the approach from the outer edge of the centripetal impellers 15 and 25 in the centripetal direction.

  The delivery space S1 on the centrifugal impellers 11 and 21 side is larger than the suction space S2 on the centripetal impellers 15 and 25 side. The fluid delivered from the centrifugal impellers 11 and 21 is delivered to the delivery space S1 at a constant flow velocity and has a constant dynamic pressure. When the fluid in the delivery space S1 moves from the delivery space S1 to the suction space S2, the fluid turns the direction by 180 ° and enters the centripetal impellers 15 and 25 from the centrifugal direction. For this reason, when the flow velocity of the fluid delivered from the centrifugal impellers 11 and 21 is high (the dynamic pressure is high), the fluid force loss of the fluid at the time of turning increases.

  In this respect, in the present embodiment, since the delivery space S1 on the centrifugal impellers 11 and 21 side is larger than the suction space S2 on the centripetal impellers 15 and 25 side, the fluid delivered from the centrifugal impellers 11 and 21 is delivered space. It is possible to decelerate in S1 to lower the dynamic pressure of the fluid and increase the static pressure. As a result, it is possible to suppress the hydraulic loss of the fluid delivered from the centrifugal impellers 11 and 21 when the fluid is rotated, and improve the pump efficiency.

  Further, in the liquid feed pump 1, the fluid suction portion 41, the housing opening portion 18a, the centrifugal impeller 11 and the centripetal impeller 15 are arranged in this order along the axis of the rotating shaft 60. Therefore, when it is necessary to arrange the fluid suction portion 41 on the axis, the fluid can be efficiently sucked from the fluid suction portion 41.

  Further, since the notch 16a or the hole 16b is formed in the centripetal impeller 15 at a position larger than the diameter D1 of the centrifugal impeller 11 of the centripetal main plate 16, the fluid sent from the centrifugal impeller 11 is It can be positively fed to the centripetal impeller 15 through the notch 16a or the hole 16b.

  Further, since the centripetal impeller 15 has the propeller portion 16c cut and raised in the rotational direction at a position larger than the diameter D1 of the centrifugal impeller 11 of the centripetal main plate 16, the centrifugal impeller 11 is separated from the centrifugal impeller 11. The delivered fluid can be positively scraped and delivered to the centripetal impeller 15 side by the propeller portion 16c.

  In addition, in the embodiment, the number of the centrifugal blades 13 and the centripetal blades 17 is six, respectively, but the number of the centrifugal blades 13 and the centripetal blades 17 is not limited to this, and is 4, 5, 7, or 8. Etc., any number of blades may be used.

  Further, in the embodiment, the centrifugal blade 13 and the centripetal blade 17 have a curved shape that is curved in the radial direction from the central portion toward the peripheral end portion in a plan view, but the curvature is the centrifugal blade 13 and the centripetal blade of the embodiment. The curvature of the centrifugal blade 13 is not limited to that of the centrifugal blade 13, and the centrifugal blade 13 can send the fluid in the centrifugal direction and the centripetal blade 17 can send the fluid in the centripetal direction. Further, the centrifugal blades 13 and the centripetal blades 17 may have a linear shape instead of a curved shape.

  Further, in the embodiment, the centrifugal impeller 11 is a closed impeller type, but the present invention is not limited to this, and an open impeller type centrifugal impeller 11 without the side plate 14 may be used. Similarly, the centripetal impeller 15 may be either a closed impeller type or an open impeller type.

  Further, in the embodiment, the centrifugal main plate 12 of the centrifugal impeller 11 and the centripetal main plate 16 of the centripetal impeller 15 are separate bodies, but the present invention is not limited to this, and the main plate of the centrifugal impeller 11 and the main plate of the centripetal impeller 15 are not limited thereto. Alternatively, the centrifugal blade 13 may be provided on the front side of the shared main plate, and the centripetal blade 17 may be provided on the back side of the shared main plate. With such a configuration, it is possible to reduce the gap between the components in the axial direction and reduce the total length of the liquid feed pump 1. Further, the number of parts can be reduced, the cost of manufacturing parts can be reduced, and the number of assembling steps can be reduced.

  Further, in the embodiment, the liquid feed pump has a total of three centrifugal impellers in which the first pump stage 10, the second pump stage 20, and the third pump stage 30 are stacked on the same axis line. The number of pump stages is not limited to four, five, six, and so on.

  DESCRIPTION OF SYMBOLS 1 ... Liquid feed pump, 10 ... 1st pump stage, 11 ... Centrifugal impeller, 15 ... Centrifugal impeller, 18 ... Pump housing, 19 ... Inner wall surface, 20 ... 2nd pump stage, 30 ... 3rd pump Steps, 40 ... Outer casing, 41 ... Fluid suction part, 60 ... Rotating shaft, D1 ... Diameter of centrifugal impeller, D2 ... Diameter of centripetal impeller, S1 ... Delivery space, S2 ... Suction space.

Claims (7)

A liquid feed pump in which a centrifugal impeller and a centripetal impeller are alternately fixed to a rotating shaft, and the centrifugal impeller and the centripetal impeller are rotatably housed in a pump housing in which a fluid flow path is formed. ,
The liquid delivery pump, wherein the centripetal impeller has a diameter larger than that of the centrifugal impeller. The liquid feed pump according to claim 1,
A housing opening is formed in the pump housing substantially coaxially with the rotating shaft,
The centrifugal impeller is arranged so as to face the housing opening,
A delivery space is provided between the inner wall surface of the pump housing and the centrifugal impeller so that the fluid introduced from the housing opening flows from the centrifugal impeller toward the centripetal impeller. Characteristic liquid feed pump. The liquid delivery pump according to claim 2,
The delivery space is
A liquid-sending pump that is larger than a suction space between the inner wall surface and the centripetal impeller in the centrifugal direction that communicates with the discharge space. The liquid delivery pump according to claim 3,
A plurality of the pump housings are arranged so as to be stacked along the axial direction of the rotating shaft,
The plurality of pump housings are communicated with each other through the housing opening so that the fluid delivered from the delivery space flows from the centripetal impeller toward the centrifugal impeller. Liquid pump. The liquid feed pump according to claim 4,
The pump housing is surrounded by an outer casing,
A fluid suction portion is opened at one end side of the outer casing,
The liquid delivery pump, wherein the fluid suction part is arranged so as to face the housing opening so that the fluid flowing from the fluid suction part flows toward the centrifugal impeller. The liquid feed pump according to any one of claims 1 to 5,
The liquid delivery pump, wherein the centripetal impeller has a notch or a hole formed at a position larger than the diameter of the centrifugal impeller. The liquid feed pump according to any one of claims 1 to 6,
The liquid delivery pump according to claim 1, wherein the centripetal impeller has a propeller portion cut and raised in a rotational direction at a position larger than a diameter of the centrifugal impeller.