JP7020276B2 - pump - Google Patents

Description

The present invention relates to a pump having a structure for suppressing backflow of fluid at a site of a closed pump rotor having a shroud.

In Patent Document 1 as a pump having the above configuration, a pump rotor (rotor in the document) is rotatably supported by a shaft member fixed inside the casing, and the outer peripheral surface of the central tubular portion of the insulator of the pump rotor is casing. A technique for improving the sealing property by providing a labyrinth structure having a large number of annular grooves on the outer surface of the tubular portion while being close to the inner surface of the cylinder has been shown.

Further, Patent Document 2 discloses a technique of providing a seal portion between a shroud (front shroud in the document) of a pump rotor (impeller in the document) that is rotated by a driving force of a canned motor and a casing.

In Patent Document 2, the seal portion is composed of an annular member arranged between the outer surface of the insulator and the inner surface of the casing.

Japanese Unexamined Patent Publication No. 2016-23635 Japanese Unexamined Patent Publication No. 2009-221938

In the pumps shown in Patent Documents 1 and 2, the fluid is sucked along the rotation axis of the pump rotor as the pump rotor rotates, and the centrifugal force associated with the rotation of the pump rotor is used to be orthogonal to the rotation axis. It is configured to pump fluid in the direction.

Further, in the pumps shown in Patent Documents 1 and 2, the central portion of the shroud that sucks the fluid has a low pressure, and the outer peripheral portion of the pump rotor that discharges the fluid has a high pressure. When the sealing performance between the pumps is low, the fluid flows from the outer periphery of the pump rotor to the center side of the shroud, which deteriorates the pump performance.

Considering the sealing performance, as shown in Patent Document 1, in the case where the outer peripheral surface of the tubular portion of the insulator is provided with a labyrinth structure, in order to improve the sealing performance, the outer peripheral surface of the tubular portion is connected to the inner surface of the casing. Although it is important to set the gap small, it is difficult to maintain the small gap with high accuracy.

Further, in the case of using the seal portion as shown in Patent Document 2, high dimensional accuracy is required for the seal portion so as to form a gap for not acting resistance on the rotation of the pump rotor.

In particular, considering the tolerance of each part constituting the pump, for example, even when the distance between the outer peripheral surface of the insulator and the inner surface of the casing is set to a predetermined value, for example, the tolerance of the pump rotor and the pump rotor are supported. As a result of the accumulation of bearing tolerances or casing tolerances, it has become difficult to maintain the spacing at an appropriate value. When a seal portion is used as shown in Patent Document 2, such an inconvenience is also affected by the tolerance of the seal portion, and there is room for improvement.

For this reason, there is a need for a pump that can control the gap for suppressing the backflow of fluid at the site of the pump rotor with high accuracy.

The characteristic configuration of the pump according to the present invention is that a fixed shaft is provided inside the casing with a rotating shaft core and a coaxial core, the pump rotor is rotatably supported with respect to the fixed shaft, and the fixed shaft is outside the pump rotor. An annular liner portion is supported on the end side, and a flow path is formed so as to send the fluid sucked through the inside of the liner portion to the pump rotor and send this fluid outward from the outer periphery of the pump rotor. In addition, the pump rotor is a closed type in which a shroud is arranged at a position facing the liner portion in a direction along the rotation axis, and the liner portion is a center holder fitted to the outer end of the fixed shaft. , And a fitting ring that fits inside the fitting recess formed in the casing, the outer peripheral surface of the tubular portion formed in the central portion of the shroud, and the inner peripheral surface of the fitting ring. And are placed in close proximity.

According to this characteristic configuration, the position of the pump rotor in the direction orthogonal to the rotation axis (radial direction) with respect to the fixed shaft is determined, so that the position of the tubular portion of the shroud is determined. Further, the position of the fitting ring of the liner portion with respect to the fixed shaft in the direction orthogonal to the rotation axis (radial direction) is determined. As a result, for example, as compared with a configuration in which positioning is performed by abutting a plurality of members, the outer peripheral surface of the tubular portion of the shroud and the fitting ring are not affected by the tolerance of the plurality of members, and the fitting ring is used as a reference. The inner peripheral surface and the position of the inner peripheral surface are determined, and the sealing performance can be obtained by arranging them in close proximity with high accuracy.
Therefore, a pump capable of controlling the gap for suppressing the backflow of the fluid at the site of the pump rotor with high accuracy has been constructed.

As another configuration, the liner portion may be movably fitted into the fitting recess in a direction along the rotation axis.

According to this, the liner portion can be easily mounted by inserting the fitting ring of the liner portion into the fitting recess in the direction along the rotation shaft core. For example, by adjusting the insertion amount, it is orthogonal to the rotation shaft core. It is also possible to set the amount of overlap with the tubular part of the shroud in the direction of view.

As another configuration, the gap between the outer peripheral surface of the tubular portion and the inner peripheral surface of the fitting ring may have a sealing function of suppressing the flow of fluid in this gap.

According to this, by reducing the seal gap to a small value, the flow of fluid between the fitting ring and the tubular portion of the shroud can be suppressed.

As another configuration, the first separation distance between the outer peripheral surface of the tubular portion and the inner peripheral surface of the fitting ring is set between the inner peripheral surface of the fitting recess and the outer peripheral surface of the fitting ring. It may be set smaller than the second separation distance.

In this configuration, for example, in a state where the first separation distance between the outer peripheral surface of the tubular portion and the inner peripheral surface of the fitting ring is set to a value at which the flow of fluid is suppressed, for example, the fitting ring of the liner portion. By abutting the end face (the end face in the direction along the axis of rotation) against the inner surface of the casing, it is possible to prevent the flow of fluid at this end face. For this reason, the second separation distance can be made larger than the first separation distance, and by setting the second separation distance to a relatively large value, the liner portion can be easily inserted into the casing.

As another configuration, the liner portion may include an intermediate rib connecting the center holder and the fitting ring.

According to this, for example, when the liner portion is configured to be arranged at the portion where the fluid is sucked in the pump, the center holder and the fitting ring are integrated by connecting with an intermediate rib and fitted with the center holder. It is possible to allow fluid to flow in the space between the ring.

It is sectional drawing of the water pump in the state which a rotor rotates. It is sectional drawing of the 2nd casing, the liner part, and the pump rotor separated state. It is sectional drawing which shows the positional relationship between a tubular part, a fitting ring, and a bulging part in a state where a rotor rotates. It is a perspective view of the separated state of a fixed shaft and a center holder.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
〔overall structure〕
In FIG. 1, a suction cylinder 23 that accommodates a pump rotor 43 that rotates about a rotating shaft core X by a driving force of a motor unit M in a casing C and sucks cooling water (an example of a fluid), and sucked cooling water. A water pump P is shown as a specific example of a pump provided with a discharge cylinder 25 (an example of a flow path) for delivering the water in a casing C.

This water pump P is configured as a centrifugal pump that sucks cooling water from the suction cylinder 23 into the pump space Sp as the pump rotor 43 rotates and sends the sucked cooling water from the discharge cylinder 25 in the tangential direction of the pump rotor 43. ing.

This water pump P is used in a vehicle such as an automobile in a form in which cooling water is circulated between the engine and the radiator. The pump having this configuration is not limited to the water pump P, and can be configured as a pump that sends out other fluids.

[Specific configuration of pump]
This water pump P can be used in any posture, but in the present embodiment, the vertical relationship will be described based on the posture shown in FIG.

As shown in FIG. 1, the casing C is configured by connecting a resin-made first casing 10, a resin-made second casing 20, and a resin-made third casing 30. In the casing C, the rotor 40 is housed in a space extending from the rotor space Sr formed inside the first casing 10 to the pump space Sp formed inside the second casing 20.

In order to connect the first casing 10 and the second casing 20 in a watertight state, the first flange portion 11 and the second flange correspond to the portions where the first casing 10 and the second casing 20 face each other. A portion 21 is formed, and these are connected by a screw 1, and a resin seal 2 is sandwiched between the connecting surfaces in order to improve the sealing property.

As shown in FIG. 1, the first casing 10 has a bottomed rotor space Sr coaxial with the rotation shaft core X, and the stator 13 is embedded in a side wall portion 12 surrounding the rotor space Sr. Further, the rotor space Sr is provided with a fixed shaft 14 coaxial with the rotating shaft core X in a form in which the base end portion is inserted into the bottom wall portion of the first casing 10.

The stator 13 includes a core 13a in which magnetic steel plates are laminated, and a coil 13b made of a conducting wire wound around the core 13a. The stator 13 is embedded in the side wall of the first casing 10 by resin potting. The fixed shaft 14 has a circular cross-sectional shape, and the shaft length is set so that the tip reaches the pump space Sp of the second casing 20.

As shown in FIG. 1, in the second casing 20, a bulging portion 22 which is coaxial with the rotating shaft core X and has a tubular shape is formed so as to project upward, and as shown in FIG. 2, from the upper wall 22b of the bulging portion 22. A suction cylinder 23 is formed which is coaxial with the rotation shaft core X and projects upward. Further, in the second casing 20, a discharge cylinder 25 is formed in a posture of tangentially delivering a fluid from an annular space surrounding the pump space Sp formed inside the bulging portion 22. In particular, as shown in FIG. 2, the fitting recess 22a is formed in a space that is a cylindrical inner surface of the bulging portion 22.

As shown in FIG. 1, the third casing 30 is formed in a bowl shape whose central portion bulges downward in order to form a space for accommodating the control substrate 31. The third casing 30 is connected to the bottom of the first casing 10, and a resin seal 2 is sandwiched between the connecting surfaces in order to improve the sealing property.

A support portion 15 projecting downward is formed in the lower portion of the first casing 10, and the control substrate 31 is supported by the support portion 15.

As shown in FIG. 1, the rotor 40 includes a bearing 41 rotatably fitted to the fixed shaft 14, and is configured by integrating a lower motor rotor 42 and an upper closed pump rotor 43. ing.

The bearing 41 is assumed to be a slide bearing with the fixed shaft 14, but may be configured by a needle bearing or the like. Further, a plurality of permanent magnets 42a are provided on the outer periphery of the motor rotor 42.

The pump rotor 43 includes a base rotor 43a having a shape protruding upward toward the center side, a shroud 43b fixed to the upper surface side of the base rotor 43a at predetermined intervals, and an impeller 43c in between thereof. Further, the shroud 43b is integrally formed with a tubular portion 43ba centered on the rotating shaft core X at the upper end.

The impeller 43c is composed of a blade integrally formed on the lower surface side of the shroud 43b, but may be integrally formed so as to project from the upper surface of the base rotor 43a.

As shown in FIGS. 1 and 2, a bush 44 is externally fitted to the upper end of the fixed shaft 14, and the liner portion 45 is externally fitted to the bush 44 and is supported.

The liner portion 45 includes a plurality of fitting rings 45a that are fitted to the upper ends of the fixed shaft 14, a fitting ring 45b that is internally fitted into the fitting recess 22a of the second casing 20, and a plurality of fitting rings 45a that connect the center holder 45a and the fitting ring 45b. It is equipped with an intermediate rib 45c (see FIG. 4).

As shown in FIGS. 1, 2, and 4, the fixed shaft 14 has a position-regulating surface 14a having a posture orthogonal to the rotation shaft core X by cutting out a part of the outer periphery of the upper end thereof, and the rotation shaft core X. A rotation restricting surface 14b having a posture along the above surface is formed. When the contact surface 45as of the center holder 45a comes into contact with the position regulation surface 14a in a state where the rotation of the rotor 40 is stopped, the position of the liner portion 45 in the direction along the rotation axis X is determined. Further, the rotation of the liner portion 45 is restricted by fitting the rotation restricting portion 45ar of the center holder 45a to the rotation restricting surface 14b.

The fitting ring 45b of the liner portion 45 is integrally formed with the upper regulation ring portion 45ba and the lower sleeve portion 45bb, and has a lower end surface 45bc at the lower end position of the sleeve portion 45bb, and the regulation ring portion 45ba. It has an upper end surface 45bd at the upper end position of.

The inner diameter of the regulation ring portion 45ba is set to be smaller than the inner diameter of the sleeve portion 45bb. Further, the outer diameter of the fitting ring 45b (the outer diameter of the region extending from the regulation ring portion 45ba to the sleeve portion 45bb) is set to a value slightly smaller than the inner diameter of the bulging portion 22. Further, by setting the outer diameter of the tubular portion 43ba to a value slightly smaller than the inner diameter of the sleeve portion 45bb, these are arranged close to each other to form a gap, and the gap suppresses the flow of cooling water. The functional unit A is configured.

[Seal function part]
The water pump P creates a flow of cooling water from the central portion of the pump rotor 43 toward the outer peripheral side as the pump rotor 43 is driven and rotated. As a result, the pressure at the central portion of the pump rotor 43 decreases, the cooling water is sucked from the suction cylinder 23, and the pressure at the portion of the pump space Sp that is close to the outer periphery of the pump rotor 43 increases, resulting in the pump space Sp. Cooling water is sent out from the discharge cylinder 25.

Since the pressure difference is created in the pump space Sp in this way, the shroud 43b and the first portion of the pump space Sp that are connected to the outer periphery of the pump rotor 43 toward the opening portion of the tip of the tubular portion 43ba of the shroud 43b. 2 Pressure acts in the direction of backflow of cooling water between the casing 20 and the casing 20.

Further, when the cooling water flows back due to the action of pressure, the efficiency of the water pump P is lowered. For this reason, the above-mentioned seal function portion A is formed for the purpose of suppressing backflow.

As shown in FIG. 3, the seal function portion A has a small distance between the outer peripheral surface of the tubular portion 43ba of the shroud 43b and the inner peripheral surface of the sleeve portion 45bb of the fitting ring 45b as the first separation distance Da. The sealing function is created by setting the value. Further, the distance between the outer peripheral surface of the fitting ring 45b and the inner peripheral surface of the bulging portion 22 is set as the second separation distance Db, and the second separation distance Db is a value larger than the above-mentioned first separation distance Da. Is set to.

In this configuration, the liner portion 45 is arranged so that the fitting ring 45b is fitted into the fitting recess 22a of the bulging portion 22, and when the rotor 40 rotates, the water pressure of the cooling water acts from the lower side. As a result, the entire liner portion 45 is lifted. As a result, the fitting ring 45b also rises, and as shown in FIGS. 1 and 3, the upper end surface 45bd of the fitting ring 45b comes into contact with the lower surface of the upper wall 22b of the bulging portion 22.

Since the water pressure of the cooling water does not act when the rotor 40 does not rotate, the lower end surface 45bc of the fitting ring 45b abuts on the upper surface of the shroud 43b, and in this state, the upper end surface 45bd of the fitting ring 45b expands. A gap is formed between the protrusion 22 and the lower surface of the upper wall 22b.

Further, since the second separation distance Db is set to a value larger than the first separation distance Da, the fitting ring 45b can be easily inserted into the bulging portion 22 when assembling the water pump P.

In this water pump P, since the rotor 40 is supported in a fixed state on the fixed shaft 14 inside the casing C, the position of the outer peripheral surface of the tubular portion 43ba in the radial direction with respect to the rotating shaft core X is determined. Further, since the liner portion 45 is supported by the fixed shaft 14, the position of the inner peripheral surface of the sleeve portion 45bb of the fitting ring 45b in the radial direction with respect to the rotating shaft core X is determined.

In this way, since each position is determined with reference to the fixed shaft 14, for example, when compared with a configuration affected by the tolerance of a plurality of members, the outer peripheral surface of the cylindrical portion 43ba and the sleeve portion 45bb of the fitting ring 45b It is possible to bring the inner peripheral surface closer to the inner peripheral surface with high accuracy. When the rotor 40 rotates, the upper end surface 45bd of the fitting ring 45b abuts on the lower surface of the upper wall 22b of the bulging portion 22 to prevent the cooling water from flowing to the outer peripheral surface of the fitting ring 45b. .. Further, in the situation where the rotor 40 rotates, although the cooling number tends to flow on the inner circumference of the fitting ring 45b, the cooling water is a gap having a small value for the first separation distance Da of the sealing function portion A at this portion. Suppresses the backflow of.

In this water pump P, the contact surface 45as of the center holder 45a comes into contact with the position regulation surface 14a of the fixed shaft 14, so that the position of the liner portion 45 in the direction along the rotation axis X is determined. Even when buoyancy does not act on the rotor 40, such as when the rotor 40 rotates at a low speed, the upper end surface 45bd of the fitting ring 45b is brought close to the lower surface of the upper wall 22b of the bulging portion 22 to provide a high sealing function. It is also possible to have.

[Action and effect of the embodiment]
From such a configuration, by controlling the electric power supplied to the coil 13b of the stator 13 of the motor unit M by the control board 31, the magnetic force acting on the permanent magnet 42a of the motor rotor 42 from the coil 13b is controlled by the rotor 40. Is rotated.

Since the rotor 40 includes a centrifugal pump rotor 43, the cooling water sucked from the suction cylinder 23 as the pump rotor 43 rotates is discharged from the discharge cylinder 25.

In this configuration, since the rotor 40 is supported by the fixed shaft 14, the position of the outer peripheral surface of the tubular portion 43ba with respect to the rotating shaft core X is determined. Further, since the liner portion 45 is supported by the fixed shaft 14, the position of the inner peripheral surface of the regulation ring portion 45ba with respect to the rotating shaft core X is determined.

Therefore, since the respective positions are determined, the outer peripheral surface of the tubular portion 43ba and the inner peripheral surface of the regulation ring portion 45ba can be brought close to each other, and the first separation distance Da is set to a small value to allow the flow of cooling water. Is well suppressed.

INDUSTRIAL APPLICABILITY The present invention can be used for a pump having a seal portion for suppressing backflow of fluid at a site of a closed pump rotor having a shroud.

14 Fixed shaft 14a Regulation surface 22a Fitting recess 25 Discharge tube (flow path)
43 Pump rotor 43b Shroud 43ba Cylindrical part 45 Liner part 45a Center holder 45b Fitting ring 45c Intermediate rib A Seal part C Casing X Rotating shaft core Da 1st separation distance Db 2nd separation distance

Claims (5)

A fixed shaft is provided inside the casing with a core coaxial with the rotating shaft, a pump rotor is rotatably supported by the fixed shaft, and an annular liner portion of the fixed shaft is supported on the outer end side of the pump rotor. A flow path is formed so as to send the fluid sucked through the inside of the liner portion to the pump rotor and send the fluid outward from the outer periphery of the pump rotor.
The pump rotor is a closed type in which a shroud is arranged at a position facing the liner portion in a direction along the rotation axis.
The liner portion has a center holder that fits to the outer end of the fixed shaft, and a fitting ring that fits inside the fitting recess formed in the casing.
A pump in which the outer peripheral surface of a tubular portion formed in the central portion of the shroud and the inner peripheral surface of the fitting ring are closely arranged. The pump according to claim 1, wherein the liner portion is movably fitted into the fitting recess in a direction along the rotation axis. The pump according to claim 1 or 2, wherein the gap between the outer peripheral surface of the tubular portion and the inner peripheral surface of the fitting ring has a sealing function of suppressing the flow of fluid in this gap. The first separation distance between the outer peripheral surface of the tubular portion and the inner peripheral surface of the fitting ring is larger than the second separation distance between the inner peripheral surface of the fitting recess and the outer peripheral surface of the fitting ring. The pump according to claim 3, which is set small. The pump according to any one of claims 1 to 4, wherein the liner portion includes an intermediate rib connecting the center holder and the fitting ring.

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