CN116075640A - Impeller and pump provided with same - Google Patents

Abstract

The present invention provides an impeller which is provided at one axial end side of a cylindrical rotor body and forms a rotor together with the rotor body, and is characterized by comprising: an impeller base provided on one end side in the axial direction of the rotor body and having a blade support surface; a plurality of blades provided on the blade support surface of the impeller base so as to extend in a curved shape from the inner side to the outer side in the radial direction of the blade support surface in a direction opposite to the rotation direction of the rotor; the annular plate-shaped front shroud is provided on the side of the plurality of blades opposite to the impeller base in the axial direction, covers the outer peripheral side portions of the plurality of blades, and has a hole portion formed in the center thereof, the inner peripheral side portions of the plurality of blades being exposed to the hole portion, and the inner diameter of the hole portion of the front shroud is larger than the outer diameter of the impeller base.

Description

Impeller and pump provided with same

Technical Field

The present invention relates to an impeller and a pump provided with the same.

Background

A pump is known, which includes: a magnetic bearing for supporting the load of a rotor provided with an impeller of a pump device by a magnetic force in a noncontact manner, and a driving unit for driving the rotor by the magnetic force (for example, refer to patent document 1). In this pump, a bearing magnet is provided on the outer periphery of a rotor, and a magnetic core as a stator member is disposed at the inner periphery of an outer case facing the bearing magnet, thereby forming a magnetic bearing.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2006-226390

Disclosure of Invention

Technical problem to be solved by the invention

However, in the pump of the prior art disclosed in patent document 1, since a magnetic bearing is used instead of a mechanical bearing, the rotor is supported in a non-contact state by magnetic levitation. Therefore, the load of the pump and the type of fluid to be transported may cause the bearing mechanism to be directly affected by the fluid, and the impeller may be displaced in the axial direction (axial thrust) or inclined in the radial direction (radial thrust), and the rotor may be broken together with the impeller, thereby causing so-called misalignment.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an impeller capable of reducing axial thrust and radial thrust, and a pump provided with the impeller.

Method for solving technical problems

An impeller according to the present invention is an impeller provided at one axial end of a cylindrical rotor body and forming a rotor together with the rotor body, the impeller including: an impeller base provided on one end side in the axial direction of the rotor body and having a blade support surface; a plurality of blades provided on the blade support surface of the impeller base so as to extend in a curved shape from an inner side to an outer side in a radial direction of the blade support surface in a direction opposite to a rotation direction of the rotor; and a circular plate-shaped front shroud provided on the side of the plurality of blades opposite to the impeller base in the axial direction, the circular plate-shaped front shroud covering portions on the outer peripheral sides of the plurality of blades and having a hole portion formed in the center thereof, portions on the inner peripheral sides of the plurality of blades being exposed to the hole portion, wherein an inner diameter of the hole portion of the front shroud is larger than an outer diameter of the impeller base.

The pump of the present invention comprises: a rotor including a cylindrical rotor body and an impeller provided at one end side in an axial direction of the rotor body; a magnetic bearing for supporting the rotor by magnetic force; a drive mechanism that rotationally drives the rotor; and a pump mechanism including the impeller, wherein the pump mechanism includes a housing having a rear case forming a housing space for housing the rotor body and a front case forming a housing space for housing the impeller, and the impeller includes: an impeller base provided on one end side in the axial direction of the rotor body and having a blade support surface; a plurality of blades provided on the blade support surface of the impeller base so as to extend in a curved shape from an inner side to an outer side in a radial direction of the blade support surface in a direction opposite to a rotation direction of the rotor; and a circular plate-shaped front shroud provided on the side of the plurality of blades opposite to the impeller base in the axial direction, the circular plate-shaped front shroud covering portions on the outer peripheral sides of the plurality of blades and having a hole portion formed in the center thereof, portions on the inner peripheral sides of the plurality of blades being exposed to the hole portion, wherein an inner diameter of the hole portion of the front shroud is larger than an outer diameter of the impeller base.

In one embodiment of the present invention, the inner diameter of the hole of the front shroud is 110% to 135% of the outer diameter of the impeller base.

In another embodiment of the present invention, the impeller base has an R-surface (rounded surface) at an outer peripheral edge portion on the blade support surface side.

In still another embodiment of the present invention, the plurality of blades have a1 st tapered portion inclined in the rotation direction on a surface of a portion of the front shroud that is disposed inside the hole portion and opposite to the blade support surface.

In still another embodiment of the present invention, the plurality of blades have a2 nd tapered portion inclined toward a side opposite to the rotation direction on a surface on the blade support surface side.

In still another embodiment of the present invention, the impeller base is formed in a cylindrical shape and has a plurality of lateral hole portions that communicate an inner peripheral portion with an outer peripheral portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the axial thrust and the radial thrust can be reduced.

Drawings

Fig. 1 is a longitudinal sectional view schematically showing the entire structure of a pump provided with an impeller according to an embodiment of the present invention, with a part cut away.

Fig. 2 is a perspective view schematically shown with a portion cut away of a rotor including the impeller.

Fig. 3 is a plan view schematically showing the impeller.

Fig. 4 is a cross-sectional view taken along line A-A' of fig. 3.

Fig. 5 is a sectional view taken along line B-B' of fig. 3.

Fig. 6 is a view schematically showing the back surface of the impeller.

Fig. 7 is an enlarged longitudinal section of a portion of fig. 1.

Detailed Description

Hereinafter, an impeller according to an embodiment of the present invention and a pump including the impeller will be described in detail with reference to the accompanying drawings. However, the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the solution of the invention. In the following embodiments, the same or corresponding components are denoted by the same reference numerals, and overlapping description thereof is omitted. In the embodiment, the proportion and the size of each component may not be the same as those of the actual components, and some of the components may be omitted.

Fig. 1 is a longitudinal sectional view schematically showing the entire structure of a pump provided with an impeller according to an embodiment of the present invention, with a part cut away.

As shown in fig. 1, a pump 100 according to the present embodiment can be used as a magnet pump for fluid transport, and includes: a rotor 120; a magnetic bearing 110 for contactlessly supporting the rotor 120 by magnetic force; a magnetically coupled drive mechanism 130 for rotationally driving the rotor 120; a pump mechanism including an impeller 190 mounted on one end side in the axial direction of the rotor 120. The pump 100 further includes a controller 210 as a control unit for controlling at least the entire pump mechanism.

In the following description, the direction of the rotation axis (Z axis) of the rotor 120 is referred to as a Z axis direction (also referred to as an axial direction, a Z direction), the radial direction of the rotor 120 is referred to as an X axis direction and a Y axis direction (also referred to as a radial direction, an X direction, and a Y direction), the rotation direction around the X axis is referred to as a Θ direction, and the rotation direction around the Y axis is referred to as a Φ direction. The side of these Θ and Φ directions that travels in the rotational direction indicated by the arrow in the figure is referred to as the + (positive) side, and the side opposite to the rotational direction indicated by the arrow in the figure is referred to as the- (negative) side. In addition, the X-axis, the Y-axis, and the Z-axis are orthogonal to each other. The right side facing the paper is referred to as the front side of the pump 100, and the left side is referred to as the rear side. Further, the front side is referred to as the + (positive) side and the rear side is referred to as the- (negative) side with respect to the Z-axis direction.

First, the overall structure of the pump 100 will be described. The pump 100 is formed in a cylindrical shape as a whole, and has a front case 141 on one side (front side) in the Z-axis direction. The front case 141 has a pump chamber A1 formed by a circular housing space in which the impeller 190 is housed, and has a cylindrical suction port 151 communicating with the pump chamber A1 at the front center. The front case 141 has a discharge port 152 on a side surface, which communicates with the pump chamber A1 as well.

The rear case 142 is connected to the rear end of the front case 141 in a state sealed by, for example, an O-ring (not shown). The rear case 142 forms a closed space a including the pump chamber A1 together with the front case 141. The rear case 142 forms a cylindrical space (accommodation space) A2 protruding rearward.

The rear side of the rear case 142 is covered with a cylindrical outer case 143 on the outer side (outer peripheral side) in the radial direction. A motor housing 134a is connected to the rear side of the housing 143, a rear cover 154 is attached to the rear side of the motor housing 134a, and a pump mount 153 for supporting the pump 100 is provided below the housing 143 and the motor housing 134 a.

The rotor 120 is accommodated in the sealed space a in a state capable of being suspended (non-contact supported). The rotor 120 is formed of a non-magnetic material such as a resin material as a whole, for example, and is integrally formed with an impeller 190 as a rotor body, the impeller 190 being provided on a front side as one end in the Z-axis direction, and the bearing/driven portion 121 being provided on a rear side as the other end in the Z-axis direction. Details of the impeller 190 are described below. Alternatively, the bearing/driven portion 121 of the rotor 120 may be first formed, and then the impeller 190 may be formed integrally by secondary molding on the bearing/driven portion 121; the impeller 190 and the bearing/driven portion 121 may be integrally formed by providing a mechanism that can be screwed together and detachably and integrally formed. The impeller 190 of the rotor 120 is housed in the pump chamber A1 inside the front case 141, and constitutes a pump mechanism together with the pump chamber A1.

On the other hand, the rear case 142 has a cylindrical projection projecting rearward from the center thereof, and the bearing/driven portion 121 of the rotor 120 is accommodated in a cylindrical space A2 inside the cylindrical projection. Inside the outer case 143, a flanged cylindrical stator support 144 is provided. Between the stator support 144 and the rear housing 142, a bearing stator 112 of the magnetic bearing 110 as described below is supported.

A magnetic bearing 110 for supporting the rotor 120 by magnetic force is provided on the outer peripheral side of the bearing/driven portion 121 of the rotor 120. Further, a driving mechanism 130 that drives the rotor 120 is provided on the inner peripheral side of the bearing/driven portion 121 of the rotor 120.

The magnetic bearing 110 includes: a bearing rotor member 111 formed of an annular magnetic material and attached to the outer peripheral side of the bearing/driven portion 121 of the rotor 120 is disposed, for example, at a predetermined interval from the bearing rotor member 111 on the outer side in the radial direction of the bearing rotor member 111 with respect to the bearing stator 112.

The bearing rotor member 111 includes: for example, the bearing magnet 113 is formed of an annular neodymium magnet, and the pair of yokes 114, 115 is formed of an annular electromagnetic soft iron, the pair of yokes 114, 115 being concentric with the bearing magnet 113 and disposed so as to sandwich both end surfaces of the bearing magnet 113 in the axial direction (Z-axis direction).

The bearing magnet 113 is magnetized such that the N pole and the S pole face each other in the axial direction, and the entire circumference in the circumferential direction is homopolar, for example. The bearing magnet 113 supplies a bias magnetic flux, not shown, to a magnetic circuit formed by a bearing rotor member 111 and a bearing stator core 117 of a bearing stator 112, which will be described later.

On the other hand, for example, a plurality of bearing stators 112 are arranged at an angle of 90 ° apart from 4 positions in the circumferential direction of the bearing rotor member 111. Of these bearing stators 112, for example, a pair of bearing stators 112 facing each other in the X-axis direction control the position of the rotor 120 in the X-axis direction and the angle in the Φ direction by the control of the controller 210, and a pair of bearing stators 112 facing each other in the Y-axis direction control the position of the rotor 120 in the Y-axis direction and the angle in the Θ direction. The bearing stators 112 control the height of the rotor 120 in the Z-axis direction.

A plurality of (for example, 4 in this case) displacement sensors (not shown) capable of detecting displacements in the radial direction and the respective rotational directions of the bearing rotor member 111 are disposed on the stator mount 144 so as to form angles of 45 ° with respect to the bearing stator 112 (i.e., angles intersecting 45 ° with respect to the X-axis direction and the Y-axis direction).

Examples of the displacement sensor include, but are not limited to, eddy current type sensors, and various sensors can be used. The number of the bearing stators 112 is not limited to the number described above, and various forms such as 6, 8, 10, 12, and 16 may be employed. The displacement sensor, although not shown, may include various sensors that are provided on the stator mount 144 or the like so as to face the bearing/driven portion 121 in the axial direction, for example, and that are capable of detecting displacement in the axial direction and the rotational direction of the bearing rotor member 111 or the like, together with the displacement sensor. The arrangement state and number of displacement sensors and the like are not limited to this, and various modes can be adopted.

In the case of the pump 100 of the present embodiment, since the impeller 190 is disposed on one side (front side) of the rotor 120, when the rotor 120 is tilted with respect to the Z axis, the rotor 120 is tilted with a position on the Z axis close to the impeller 190 as a rotation center. Therefore, although not shown, if a displacement sensor is disposed in advance at a position distant from the impeller 190, for example, preferably at a position at the center in the Z-axis direction of the bearing/driven portion 121, the position of the rotor 120 in the X-axis direction and the angle in the Φ direction, the position in the Y-axis direction and the angle in the Θ direction can be detected by the displacement sensor, and therefore, the inclination of the rotation axis can be sufficiently controlled by the biaxial control.

The bearing stator 112 includes: for example, a bearing stator core 117 formed of a magnetic material such as a laminated electromagnetic steel sheet, and a bearing coil 118 wound around the bearing stator core 117. The vertical cross-sectional shape of the bearing stator core 117 is, for example, a substantially C-shape (コ -shape) with an open end formed on the bearing rotor member 111 side.

Specifically, bearing stator core 117 has a longitudinal cross-sectional shape that includes: part 1, for example, extends in a Z-axis direction orthogonal to a direction (radial direction) facing the bearing rotor member 111, and the bearing coil 118 is wound around the part 1; a pair of 2 nd portions extending from both end portions of the 1 st portion in the Z-axis direction toward the bearing rotor member 111 side and then extending in the Z-axis direction toward each other; a pair of 3 rd portions extending from the respective distal ends of the pair of 2 nd portions toward the bearing rotor member 111 side. In other words, it can be said that the longitudinal section shape of the bearing stator core 117 is: the pair of key-shaped portions are provided at the C-shaped open end portions extending straight from the two ends of the 1 st portion around which the bearing coil 118 is wound in the Z-axis direction toward the bearing rotor member 111, and have shapes in which the open end portions are close to each other.

In this shape, as shown in the figure, the length of the bearing coil 118 in the Z-axis direction can be made longer than the distance between the surfaces of the pair of 3 rd portions on the open end side of the bearing stator core 117, which are opposed in the Z-axis direction. That is, the distance between the tips of the open ends can be made smaller than the length of the wound portion of the bearing coil 118 in the Z-axis direction. In addition, the width of the open end side of the bearing stator core 117, that is, the distance between the surfaces of the pair of 3 rd portions on the opposite side to the surfaces facing in the Z-axis direction can be made smaller than the length of the bearing stator core 117 originally in the Z-axis direction and substantially equal to the length of the bearing rotor member 111 in the Z-axis direction.

The driving mechanism 130 includes: a driven magnet 131 as an annular driven member attached to an inner peripheral side of the bearing/driven portion 121 of the rotor 120; for example, a driving magnet 132 as a driving unit is disposed on the inner side of the driven magnet 131 in the radial direction with a predetermined interval therebetween.

The driving mechanism 130 further includes: a motor shaft 133 having the driving magnet 132 mounted on the top thereof and rotatably supported by a bearing 135; the motor shaft 133 is driven to rotate by the drive motor 134. In the present embodiment, the driven magnet 131 and the driving magnet 132 are composed of, for example, neodymium magnets magnetized in the radial direction to 2 or 4 poles. In the present embodiment, the drive magnet 132 and the motor shaft 133 have substantially the same diameter, but the two are not necessarily the same diameter.

The controller 210 detects displacements of the rotor 120 in various directions and in various rotational directions based on detection signals from various sensors including the displacement sensor described above, and finely controls the current flowing in the bearing coil 118 of the bearing stator 112 of the magnetic bearing 110 in accordance therewith. Thus, the position and angle of the rotor 120 in the X-axis direction and the Φ -direction, the position and angle in the Y-axis direction and the θ -direction, and the height in the Z-axis direction can be controlled in real time, and the rotational position can be corrected.

The controller 210 includes, for example: a drive board 211 provided with a MOS-FET or the like for driving the bearing coil 118 of the magnetic bearing 110; a CPU board 212 for controlling the operation of the magnetic bearing 110 and the driving mechanism 130; and an encoder substrate 213 for processing signals from various sensors and controlling a magnetic encoder or the like, not shown.

The controller 210 is disposed on the rear side of the stator support 144. A cooling fan 169 that uses a rotary blade is mounted on the motor shaft 133 of the drive motor 134 on the rear side of the controller 210. These controller 210 and cooling fan 169 are disposed inside the outer case 143.

Next, the impeller 190 of the rotor 120 of the pump 100 will be described.

Fig. 2 is a perspective view schematically showing a rotor 120 including an impeller 190 with a part cut away, fig. 3 is a plan view schematically showing the impeller 190, fig. 4 is a sectional view taken along line A-A 'of fig. 3, fig. 5 is a sectional view taken along line B-B' of fig. 3, and fig. 6 is a view schematically showing the back side of the impeller 190.

The impeller 190 of the rotor 120 includes: an impeller base 191, a plurality of blades 192, and a front shroud 193.

The impeller base 191 is a thin flanged cylindrical member made of a non-magnetic material such as a resin material, and capable of being integrally connected to the bearing/driven portion 121 as a rotor body. The impeller base 191 may be detachably attached to the bearing/driven portion 121 by screw portions 191a, 121a as shown in the figure, or may be integrally provided to the bearing/driven portion 121 by overmolding or the like.

The impeller base 191 has an annular blade support surface 191b on the front shroud 193 side. The plurality of blades 192 extend in a curved shape from the inner side to the outer side in the radial direction of the blade support surface 191b of the impeller base 191 in the direction opposite to the rotation direction of the rotor 120 shown by the arrows in fig. 2, 3, and 6, and are provided with 5 blades, for example. A front shroud (front side plate) 193 having a circular ring plate shape is provided on the front side (front side) of the plurality of blades 192 on the opposite side of the impeller base 191 in the Z-axis direction.

The front shroud 193 covers the outer peripheral side portions of the plurality of blades 192 from the front side, and has a circular center hole (hole portion) 193a in the center. Portions of the inner peripheral sides of the plurality of blades 192 are exposed from the center hole 193a. The inner diameter D2 of the center hole 193a is larger than the outer diameter T2 of the impeller base 191. This is to ensure a flow path area of the transport fluid sucked from the suction port 151 of the pump 100 and moved toward the rear case 142 through the center hole 193a. In order to further secure this flow path area, the impeller base 191 has an R-surface (rounded surface) 191c on the outer peripheral edge portion of the vane support surface 191b, as shown in fig. 4.

The plurality of blades 192 have a1 st tapered portion 194 (see fig. 5) inclined in the rotation direction on the surface of a portion disposed inside the center hole 193a. The plurality of blades 192 have a2 nd tapered surface portion 195 (see fig. 5) inclined toward the side opposite to the rotation direction on the back surface of the rear side (rear side) of the front shroud 193.

In other words, the 1 st tapered surface portion 194 is constituted by a tapered surface that is inclined downward in the rotation direction from the end 192a on the upstream side in the rotation direction of the front side of the portion of the vane 192 exposed from the center hole 193a. In other words, the 2 nd tapered surface portion 195 is formed by a tapered surface that obliquely rises in a direction opposite to the rotation direction from the end 192b on the downstream side in the rotation direction of the rear side of the portion formed on the rear side of the front shroud 193 of the blade 192.

As shown in fig. 4, a plurality of side holes (lateral hole portions) 191d are formed in the impeller base 191, and when the impeller base 191 is connected to the bearing/driven portion 121, the plurality of side holes (lateral hole portions) 191d communicate the inner space of the rotor 120 (inner space A3 of the bearing/driven portion 121: see fig. 4) with the housing space (pump chamber A1) of the front case 141. The side holes 191d have a circular, elliptical, or flat elliptical shape, etc., and are provided so as to penetrate the impeller base 191 radially in the radial direction (radial direction) from the rotation axis center of the rotor 120, for example, 4 are provided here.

Next, the operation of the pump 100 having the impeller 190 configured as described above will be described.

In the case of a pump in which a rotor is supported by a magnetic bearing, it is difficult to mechanically restrict movement of the rotor, and therefore, problems such as movement and inclination of the rotor in the axial direction occur. As shown in the pump 100 of the present embodiment, when the suction port 151 is positioned in front of the pump chamber A1, suction of the transport fluid causes a pressure decrease in the pump chamber A1 on the suction port 151 side. If the impeller 190 is open without the front shroud 193, the rotor 120 is largely moved toward the +side (front side) in the axial direction, and also inclined in the radial direction. In addition, in the case of a closed type in which shrouds are provided on both sides of the blades 192 and a semi-open type in which a rear shroud is provided on the rear surface side of the blades 192, the rotor 120 also moves toward the +side in the axial direction.

In this regard, in the pump 100 of the present embodiment, since the impeller 190 adopts a half-open form in which the annular front shroud 193 is provided in front of the blades 192, a pressure drop due to an increase in the flow rate of the transport fluid generated on the rear surface side of the front shroud 193 causes a force to move the rotor 120 toward the rear casing 142. Therefore, this force balances the forward movement force caused by the pressure decrease at the suction port 151, and prevents the rotor 120 from moving in the axial direction. In addition, the rotor 120 can be prevented from tilting by the inertial action when the front shroud 193 rotates.

Here, if the inner diameter D2 of the center hole 193a of the front shroud 193 is smaller than the outer diameter T2 of the impeller base 191, the flow path cross-sectional area of the transport fluid transported from the suction port 151 of the pump 100 toward the rear casing 142 side cannot be ensured, the pressure on the suction port 151 side does not decrease, the amount of movement of the rotor 120 toward the-side (rear side) in the axial direction becomes excessively large, and there is a possibility that the rotor 120 contacts the rear casing 142.

On the other hand, if the inner diameter D2 of the center hole 193a of the front shroud 193 is excessively larger than the outer diameter T2 of the impeller base 191, the decompression effect on the back side of the front shroud 193 cannot be sufficiently obtained, preventing the rotor 120 from moving toward the rear case 142 side and the tilting function from deteriorating.

As is clear from experiments conducted by the present inventors and the like relating to this point, the front shroud 193 is preferably formed such that the inner diameter D2 of the center hole 193a is 110% to 135%, preferably 113% to 120%, of the outer diameter T2 of the bearing/driven portion 121.

The decompression effect on the rear surface side of the front shroud 193 varies depending on the outer diameter D1 of the front shroud 193. As a result of experiments performed by the present inventors, it was found that the smaller the outer diameter D1 of the front shroud 193, the greater the inclination of the rotor 120. This is believed to be due to the fastest flow rate and lowest pressure of the fluid being delivered near the discharge port 152. If the outer diameter D1 of the front shroud 193 is not sufficiently large with respect to the pump chamber A1, it is difficult to balance the pressure in the vicinity of the discharge port 152. As a result of experiments conducted by the present inventors, it was found that the front shroud 193 is preferably formed such that the outer diameter (outer diameter of the impeller 190) D1 thereof is 85% or more and less than 100%, preferably 90% or more and 94% or less of the inner diameter T1 of the housing space (pump chamber A1) of the front case 141.

The movement of the rotor 120 in the axial direction can be adjusted by adjusting the angle of the 1 st tapered portion 194 and/or the 2 nd tapered portion 195 formed in the vane 192. That is, when the 1 st taper portion 194 and/or the 2 nd taper portion 195 are inclined at the inclination angles η1, η2 with respect to the rotation direction, respectively, as shown in fig. 5, a thrust force is generated on the impeller 190 toward the rear case 142 side, and therefore the rotor 120 moves toward the axial direction-side. According to experiments performed by the present inventors, the 1 st taper portion 194 is preferably formed so that the inclination angle η1 is in the range of 15 ° to 30 ° with respect to the surface (horizontal plane) of the front shroud 193, for example. The 2 nd tapered surface portion 195 is preferably formed so that the inclination angle η2 is in the range of 15 ° to 30 ° with respect to the rear surface (horizontal surface) of the front shroud 193, for example. In the case where fine adjustment of the rotor 120 in the axial direction is not required, the 1 st taper portion 194 and/or the 2 nd taper portion 195 may not be provided.

Further, if a side hole 191d penetrating the side surface direction of the impeller base 191 located on the rear surface side of the impeller 190 is provided, the movement of the impeller 190 toward the front case 141 side (axial direction+side) is suppressed. That is, the flow of the transport fluid formed by the impeller 190 is discharged from the discharge port 152, and also flows in the gap (including the cylindrical space (accommodation space)) between the rear case 142 and the bearing/driven portion 121 as shown by the arrow in fig. 7.

The flow of the transport fluid from the pump chamber A1 to the rear case 142 side passes through and flows around the outer peripheral side of the bearing/driven portion 121 of the cylindrical space A2, passes through the inner space A3 of the bearing/driven portion 121, and rapidly flows out from the side hole 191d provided on the rear surface side of the impeller 190, thereby producing an effect of reducing the pressure of the rotor 120 on the rear surface side (rear side) of the impeller 190. On the back surface side, a force obtained by multiplying the pressure receiving area thereof by the internal pressure in the vicinity of the bottom surface of the rear case 142 (the bottom surface of the cylindrical space A2) becomes a force for moving the impeller 190 toward the front case 141 side (the axial direction +side). Therefore, by reducing the pressure on the back surface side of the impeller 190 using the side hole 191d, the amount of movement toward the +side in the axial direction can be suppressed.

Although the embodiments of the present invention have been described above, the embodiments are presented by way of example only and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other modes, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope equivalent to the invention described in the scope of the invention request.

For example, in the above-described embodiment, the side holes 191d of the impeller 190 are formed in a circular, elliptical or flat elliptical shape and 4 blades 192 are formed in 5 blades, but the number, shape, arrangement state, and the like thereof can be variously employed based on the kind of the fluid to be transported, the design performance of the pump 100, and the like, and are therefore not limited to the number, shape, arrangement state described above. In the above embodiment, the impeller 190 of the rotor 120 supported by a magnetic bearing has been described as an example, but the present invention is applicable to a rotor supported by a mechanical bearing. In this case, too, there is an effect that unnecessary loads such as an axial direction and a tilt are not generated.

Description of the reference numerals

100. Pump with a pump body

110. Magnetic bearing

120. Rotor

121. Bearing/driven part (rotor body)

130. Driving mechanism

190. Impeller wheel

191. Impeller base

191b blade bearing surface

191d side hole

192. Blade

193. Front shield

193a central hole

194. 1 st conical surface part

195. 2 nd conical surface part

210. Controller for controlling a power supply

Claims (12)

1. An impeller provided at one axial end of a cylindrical rotor body and forming a rotor together with the rotor body, comprising:

an impeller base provided on one end side in the axial direction of the rotor body and having a blade support surface;

a plurality of blades provided on the blade support surface of the impeller base so as to extend in a curved shape from an inner side to an outer side in a radial direction of the blade support surface in a direction opposite to a rotation direction of the rotor;

a circular plate-shaped front shroud provided on the opposite side of the plurality of blades from the impeller base in the axial direction, the circular plate-shaped front shroud covering portions of the plurality of blades on the outer peripheral side and having a hole portion formed in the center, portions of the plurality of blades on the inner peripheral side being exposed to the hole portion, wherein

The bore of the front shroud has an inner diameter that is greater than an outer diameter of the impeller base.

2. The impeller of claim 1, wherein the impeller comprises a plurality of blades,

the inner diameter of the hole of the front shield is 110% -135% of the outer diameter of the impeller base.

3. An impeller according to claim 1 or 2, characterized in that,

the impeller base has an R-surface at an outer peripheral edge portion on the blade support surface side.

4. An impeller according to any one of claims 1 to 3, characterized in that,

the plurality of blades have a1 st tapered surface portion inclined toward the rotation direction on a surface of a portion of the front shroud that is disposed inside the hole portion and opposite to the blade support surface.

5. The impeller according to any one of claims 1 to 4, wherein,

the plurality of blades have a2 nd tapered surface portion inclined toward a side opposite to the rotation direction on a surface on the blade support surface side.

6. The impeller according to any one of claims 1 to 5, wherein,

the impeller base is formed in a cylindrical shape and

the inner peripheral portion and the outer peripheral portion are connected by a plurality of cross holes.

7. A pump is provided with:

a rotor, comprising: a cylindrical rotor body, and an impeller provided at one end side in an axial direction of the rotor body;

a magnetic bearing for supporting the rotor by magnetic force;

a drive mechanism that rotationally drives the rotor; and

a pump mechanism comprising said impeller wheel,

wherein,,

the pump mechanism includes a housing having a rear case forming a housing space for housing the rotor body and a front case forming a housing space for housing the impeller,

the impeller is provided with:

an impeller base provided on one end side in the axial direction of the rotor body and having a blade support surface;

a plurality of blades provided on the blade support surface of the impeller base so as to extend in a curved shape from an inner side to an outer side in a radial direction of the blade support surface in a direction opposite to a rotation direction of the rotor;

a circular plate-shaped front shroud provided on the opposite side of the plurality of blades from the impeller base in the axial direction, the circular plate-shaped front shroud covering portions of the plurality of blades on the outer peripheral side and having a hole portion formed in the center, portions of the plurality of blades on the inner peripheral side being exposed to the hole portion, wherein

The bore of the front shroud has an inner diameter that is greater than an outer diameter of the impeller base.

8. The pump according to claim 7, wherein,

the inner diameter of the hole of the front shield is 110% -135% of the outer diameter of the impeller base.

9. The pump according to claim 7 or 8, wherein,

the impeller base has an R-surface at an outer peripheral edge portion on the blade support surface side.

10. The pump according to any one of claim 7 to 9,

the plurality of blades have a1 st tapered surface portion inclined in the rotation direction on a surface of a portion of the front shroud that is disposed inside the hole portion and opposite to the blade support surface.

11. The pump according to any one of claim 7 to 10,

the plurality of blades have a2 nd tapered surface portion inclined toward a side opposite to the rotation direction on a surface on the blade support surface side.

12. The pump according to any one of claim 7 to 11,

the impeller base is formed in a cylindrical shape and

the inner peripheral portion and the outer peripheral portion are connected by a plurality of cross holes.

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