JP2000274396A - Pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high efficiency of a pump at a low cost with a simple constitution, and to enhance the reliability of the pump. SOLUTION: It is so constituted that an impeller to be drivingly rotated by a stator while being mounted to a stationary shaft coaxially disposed with a flow path within a pump housing, is formed out of a bearing 1 to be held so as to be freely rotated with respect to the stationary shaft, vanes 2 pressing fluid fowing in out of the suction part of a pump disposed around the bearing 1 by means of rotation, a front surface shroud 4 to which a magnet 3 disposed in such a way that the vanes 2 are enclosed, is fixed, and of a positioning plate 6 for positioning the front surface shroud 4 and the magnet 3, the respective parts of the vanes 2, a bearing holding part 5 and the front surface shroud 4, are integrally formed up so as to be engaged with the magnet 3, so that a rotation prevention mechanism regulating its rotation, is thereby prepared therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump having an axial-flow type impeller, and more particularly to an improvement in an impeller assembly structure.

[0002]

2. Description of the Related Art Conventionally, pumps for assembling equipment have been demanded to be smaller and lighter in light of the trend toward smaller and lighter equipment. As one of the means, there has been provided a multi-flow, low-head pump in which a pump impeller is formed integrally with a motor impeller and forms a part of piping.

As an example of such a multi-flow, low-head pump, there is an axial-flow pump described in US Pat. No. 2,697,986, and its structure is schematically shown in FIG.

In FIG. 9, reference numeral 101 denotes a housing, 10
2 is a suction flange of the pump, 103 is a blade for pressurizing the fluid, and 104 is a discharge flange of the pump. A rib 108 is formed on the housing 101, and a bearing holding portion 107 is connected to the rib 108, and the bearing 1 is attached to the bearing holding portion 107.
06 is arranged. The blade 103 is fixed to the rotating shaft 105 supported by the bearing 106. An impeller 110 containing a permanent magnet 109 is integrated around the blade 103, and a stator 111 is arranged around the impeller 110. By energizing the stator 111, the impeller 110 can be rotated.

[0005] The housing 10 of the pump having such a structure.
1 is an annular suction flange 102 and a discharge flange 104
And is connected to a pipe (not shown), and is incorporated into the pipe on a line. The fluid sucked from the suction flange 102 is pressurized by the rotating impeller 110 by energizing the stator 111, and then the discharge flange 1 is turned on.
Sent from 04. It should be noted that a device using a screw instead of the blade 103 has the same function.

On the other hand, as a pump used when a high head is required, an impeller 110 in the prior art shown in FIG. 9 is used.
A configuration in which the inner flow path is bent toward the outer periphery and pressure is applied by centrifugal force has already been proposed.

As described above, the basic structure of a conventional pump is to dispose a blade or a screw in an impeller which is driven to rotate by a stator. It is to promote miniaturization.

[0008]

The conventional pump employs an axial flow type pump as shown in FIG. 9 for downsizing, and is adapted to high-speed operation in order to offset the shortage of head due to downsizing. It is to raise the head. However, there is a limit to speeding up, mainly due to the inevitable occurrence of vibration and noise due to the eccentricity of the impeller.

On the other hand, to improve pump efficiency, 3
Dimensional wing impellers have also been widely known. However, the structure of the impeller of the three-dimensional blade is complicated due to the relationship of the resin molding die and the like, so that the cost is high, and the assemblability is complicated, so that the productivity is greatly affected.

[0010] In order to improve the pump efficiency, it is optimal to minimize the gap between the housing and the impeller. However, the fluid passing through the pump usually contains hard suspended matter, and the suspended matter comes into contact with the flow path wall to cause wear, so that the gap gradually widens. For this reason, the performance of the pump is degraded, or in the worst case, a foreign substance is caught in the gap, causing clogging and damaging the pump. In particular, since tap water often contains iron scraps, there is a possibility that performance deterioration due to such abrasion and the frequency of damage to the pump may increase.

Accordingly, an object of the present invention is to realize high efficiency of a pump with a simple configuration at low cost and to improve the reliability of the pump.

[0012]

According to the present invention, there is provided a pump including a housing having a fluid suction part and a discharge part, a flow path formed between the suction part and the discharge part, and an external part around the flow path. And a fixed shaft having an axis in a direction from the suction portion to the discharge portion, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, the pump comprising: The vehicle has a bearing rotatably held with respect to the fixed shaft, blades arranged around the bearing to pressurize fluid flowing from the suction portion by rotation, and a front surface on which a magnet is fixed so as to surround the blade. A shroud, a bearing holding unit for fixing the bearing to the blade, and a positioning plate for positioning the front shroud and the magnet, each unit comprising: the blade and the bearing holding unit; Each section of the shroud engages the magnet with integrally molded and having a rotation preventing mechanism for restricting the rotation.

In such a configuration, the number of parts can be reduced by integral molding, and the integral molding suppresses the eccentric operation of the blades to enable high-speed rotation of the impeller. Even if the pump is small, the required head and flow rate can be reduced. can get.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to a first aspect of the present invention is directed to a housing having a fluid suction part and a discharge part, a flow path formed between the suction part and the discharge part, and a housing around the flow path. A pump including an externally provided stator, a fixed shaft having an axis extending from the suction portion to the discharge portion, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator. The impeller has a bearing rotatably held with respect to the fixed shaft, a blade disposed around the bearing and pressurizing a fluid flowing from the suction part by rotation, and a magnet fixed to surround the blade. The front shroud, a bearing holding portion for fixing the bearing to the blade, and a positioning plate for positioning the front shroud and the magnet constitute respective parts, and the blade and the bearing holding portion and the front shell are formed. A pump having a rotation preventing mechanism that integrally forms each part of the loud and controls the rotation by engaging with the magnet, thereby reducing the number of components and reducing the weight imbalance around the axis. As a result, high-speed operation is possible, and downsizing of the pump and high efficiency of output can be realized at low cost.

According to a second aspect of the present invention, there is provided a housing having a suction part and a discharge part for a fluid and a flow path formed between the suction part and the discharge part, and a housing provided outside the flow path. A pump having a stator, a fixed shaft having an axis from the suction portion to the discharge portion, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller includes: A bearing rotatably held with respect to the fixed shaft, blades arranged around the bearing to pressurize fluid flowing in from the suction portion by rotation, and a front shroud arranged to surround the blades and fixed with a magnet And a bearing holding portion for fixing the bearing to the blade, and a rear shroud arranged in contact with a rear end of the blade and guiding fluid between the blades, and constitutes each portion, and the blade and the bearing holding portion are formed. A part and each part of the front shroud are integrally formed, a contact surface between the blade and the rear shroud is a conical surface, and a center part of the rear shroud is a contact surface with the bearing. Since the pump is a feature, the number of steps can be simplified and the accuracy can be increased in the assembly of the impeller, so that the cost of the pump and the efficiency of the output can be increased.

According to a third aspect of the present invention, there is provided a housing including a fluid suction portion and a discharge portion, a flow passage formed between the suction portion and the discharge portion, and a stator provided outside the flow passage around the flow passage. A pump having: a fixed shaft having an axis in a direction from the suction portion to the discharge portion; and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator. A bearing rotatably held with respect to a shaft, a blade disposed around the bearing and pressurizing the fluid flowing from the suction portion by rotation, and a front shroud arranged around the blade and fixed with a magnet, A bearing holding portion for fixing the bearing to the blade, and a rear shroud which is disposed in contact with a rear end portion of the blade and guides fluid between the blades, constitutes respective portions, and includes the blade and the bearing holding portion. Each part of the front shroud is integrally formed, the contact surface between the blade and the rear shroud is a conical surface, and the central front surface of the rear shroud and the rear surface of the bearing holding portion are the contact surface. This is a pump characterized by the fact that the structure of the impeller becomes strong, so that high output efficiency can be realized.

According to a fourth aspect of the present invention, the blade and the bearing holding portion are provided on a joint surface between the front shroud and the rear shroud, and an unmelted contact area is smaller than an area at the time of joining. 4. The pump according to claim 2, wherein the impeller is integrally joined by melting, so that the structure of the impeller becomes strong and the shape and dimensions after assembly are stable, so that high-speed operation becomes possible and the output of the pump is improved. Efficiency can be realized.

According to a fifth aspect of the present invention, the blade and the bearing holding portion are positioned relative to each other between the front shroud and the rear shroud and between the bearing holding portion and the rear shroud. 4. The pump according to claim 3, wherein the pump is joined by the concave / convex engagement provided on the abutting surface, so that the number of assembling steps of the impeller can be simplified and the shape and dimensions after the impeller is assembled can be stabilized. In addition, high-speed operation becomes possible, and miniaturization of the pump and high efficiency of output can be realized at low cost.

According to a sixth aspect of the present invention, there is provided a housing including a fluid suction part and a discharge part, a flow path formed between the suction part and the discharge part, and a housing provided outside the flow path. A pump having a stator, a fixed shaft having an axis from the suction portion to the discharge portion, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller includes: A bearing rotatably held with respect to the fixed shaft, blades arranged around the bearing to pressurize fluid flowing in from the suction portion by rotation, and a front shroud arranged to surround the blades and fixed with a magnet A rear shroud disposed at a rear end of the impeller for guiding fluid between the blades in the impeller; and a magnet cover extrapolated around the outer periphery of the magnet, wherein the rear shroud and the magnet cover are provided. The a pump, characterized in that molded integrally, since assembling steps of the impeller with the reduction of components can be simplified, the cost of the pump is possible.

According to a seventh aspect of the present invention, there is provided a housing having a suction part and a discharge part for a fluid, a flow path formed between the suction part and the discharge part, and a housing provided outside the flow path. A pump having a stator, a fixed shaft having an axis from the suction portion to the discharge portion, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller includes: A bearing rotatably held on the fixed shaft, a blade arranged around the bearing and pressurizing a fluid flowing from the suction portion by rotation, a bearing holding portion for fixing the bearing to the blade, and the blade And a front shroud to which a magnet is fixed so as to surround the magnet, and a part of the magnet is made to face the flow passage, thereby improving the reliability of the pump.

The invention according to claim 8 is a housing provided with a fluid suction part and a discharge part and a flow path formed between the suction part and the discharge part, and provided outside the periphery of the flow path. A pump having a stator, a fixed shaft having an axis from the suction portion to the discharge portion, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller includes: A bearing rotatably held on the fixed shaft, a blade arranged around the bearing and pressurizing a fluid flowing from the suction portion by rotation, a bearing holding portion for fixing the bearing to the blade, and the blade And a front shroud to which a magnet is fixed and which surrounds the front shroud, and wherein the front shroud, the bearing holding portion, and the blades are integrally formed by a magnet. It reduces the number of components, simplifies the man-hour for assembling the impeller, and reduces the weight imbalance around the shaft, enabling high-speed operation, miniaturizing the pump and increasing the efficiency of output. High reliability can be realized at low cost.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an embodiment of the invention according to claim 1, and is a structural view of an impeller disposed inside a pump, (a) is an external view thereof, and (b) is an (a) of FIG. FIG. 2 is a vertical sectional view taken along line AA. The impeller of each of the following examples is mounted on a fixed shaft that is incorporated and fixed in the pump housing as the same arrangement as the rotating shaft 105 shown in FIG. 9, and is driven to rotate by a stator disposed therearound. is there.

In FIG. 1, it is assumed that the impeller is incorporated in a fluid flow path where the suction port of the pump is located on the right side. The impeller has a bearing 1, which is rotatably held on a fixed shaft (not shown) fixed in the pump housing with an axis extending from the suction portion toward the discharge portion.
A blade 2 that pressurizes a fluid flowing from an opening communicating with a suction port of the pump by rotation; a magnet 3 mounted on an outer peripheral portion of the blade 2 and driving an impeller by energizing a coil (not shown in the drawing); A front shroud 4 arranged so as to surround the blade 2 and fixing the magnet 3 to the blade 2, a bearing holder 5 for fixing the bearing 1 to the blade 2, and a magnet 3 for the front shroud 4.
And a positioning plate 6 for positioning.

In this embodiment, since the bearing holding portion 5 and the front shroud 4 are integrally formed of resin so as to be connected by the blades 2, the cylindrical surface of the bearing holding portion 5 with which the bearing 1 abuts and the front shroud 4. The coaxiality of the cylindrical surface with which the magnet 3 abuts depends only on the resin molding die. That is, the center of gravity of the magnet 3 occupying a large mass in the impeller can be accurately positioned with respect to the rotating shaft passing through the center of the bearing 1 only by improving the accuracy of the mold. Since such manufacturing is possible, the eccentricity of the impeller becomes extremely small, and even if the pump is operated at a high speed, noise, vibration, and other factors that hinder the high speed operation of the pump are eliminated. It is needless to say that the variation in the eccentricity of each impeller is reduced due to the dependence on the mold, and the performance variation of each pump is also suppressed.

In this embodiment, the magnet 3 is fixed to the front shroud 4 by sandwiching the magnet 3 placed on the front shroud 4 with the positioning plate 6 and, as shown in a detailed view, the end of the front shroud 4. The positioning plate 6 is bonded. However, when an external driving force is instantaneously applied to the magnet 3, there is a possibility that only the magnet 3 cannot be rotated because the friction force between the front shroud 4 or the positioning plate 6 and the magnet 3 alone cannot withstand. is there. In particular, depending on the temperature of the fluid to be handled, a situation may occur in which the frictional force becomes extremely small due to the difference in the coefficient of linear expansion. Therefore, as shown in FIG. 1A, if the uneven portion 11 is provided on the magnet 3 and the front shroud 4 as a rotation preventing mechanism, idling of the magnet 3 can be prevented. It should be noted that the same effect can be obtained even if the uneven portion 11 is provided between the magnet 3 and the positioning plate 6.

FIG. 2 shows an embodiment according to the second aspect of the present invention, in which (a) is a perspective view of an impeller and a rear shroud,
(B) is a longitudinal sectional view of the impeller. The configuration of the impeller is the same as that shown in FIG. 1, and the same members are denoted by the same reference numerals. This is the same in the embodiments shown in FIGS.

In FIG. 2, reference numeral 7 denotes a rear shroud which is located downstream of the blade 2 and guides fluid between the blades 2. The rear shroud 7 includes the blade 2, the front shroud 4, and the bearing holder 5.
The three parts function by being adhered to the integrally molded part.
At this time, since the rear surface of the blade 2 and the front surface of the rear shroud 7 are the joint surface 12 formed of the same cone, the central portion of the rear shroud 7 is assembled with the bearing holding portion 5 during assembly.
, The centering operation and the bonding operation can be performed manually. Therefore, the number of steps for setting parts on a special tool for centering can be omitted, and cost can be reduced. Further, since the centering operation itself is performed directly on the molded part, there is no error in setting the part on the jig. Therefore, the positioning accuracy is improved, the weight imbalance of the impeller is suppressed, and the gap between the housing and the impeller does not unnecessarily expand, so that the pump efficiency can be increased.

FIG. 3 is a perspective view of an impeller and a rear shroud according to an embodiment of the present invention.

In this embodiment, the rear shroud 7 having the same structure as that shown in FIG. 2 is integrated with the rear surface of the bearing holder 5 as an adhesive surface. With such an adhesive structure, the adhesive strength between the rear shroud 7 and the blades 2 can be increased, and the rigidity of the impeller is increased, and unnecessary resonance does not occur.

FIG. 4 is a perspective view of an impeller according to an embodiment of the present invention.

In FIG. 4, reference numeral 8 denotes a convex welding margin provided on the rear surface of the blade 2, to which the rear shroud is integrally bonded in the same manner as shown in FIGS.

Here, when the fluid to be handled is a liquid, particularly water, if a resin or the like is applied to the contact surface of the component and cured by so-called resin bonding, the adhesive swells with water and the external precision is maintained. They may not be peeled or may be peeled off in the worst case. For this reason, it is desirable to adhere the rear shroud (not shown) by heat welding of the parts by ultrasonic waves from the viewpoint of reliability. However, in this method, since the outer shape of the component is melted by heat generated by ultrasonic waves, the height of the contact surface changes, and condition management such as transmission of ultrasonic waves is essential for high-precision bonding. On the other hand, if the welding allowance 8 is formed on the contact surface from the beginning, the heat energy by the ultrasonic wave is concentrated on the welding allowance 8, and it is the welding allowance 8 that starts melting due to the generation of heat. Since the area of contact at the point of complete melting is rapidly increased, the generated heat is rapidly reduced, and the welding is completed on the predetermined surfaces. In other words, even if the ultrasonic conditions vary to some extent, the welding margin 8 is melted, and if the heat generated is insufficient for melting the resin even when the area of the predetermined surface abuts, high-precision welding is possible. It is. Further, since welding is reliably performed on the entire contact surface between the blade 2 and the rear shroud, the strength is improved and high-speed operation is possible.

FIG. 5 is a perspective view of an impeller according to an embodiment of the present invention.

In the present embodiment, an uneven portion 9 is provided on the contact surface between the rear surface of the bearing holder 5 and a rear shroud (not shown). In such a configuration, by fixing the rear shroud to the blade 2 as a combination of those shown in FIGS. 3 and 4, the positioning and bonding of the rear shroud can be performed with higher accuracy.

FIGS. 6A and 6B show an embodiment according to claim 6, wherein FIG. 6A is an external perspective view and FIG. 6B is a longitudinal sectional view.

In this embodiment, the magnet cover 10 is integrally provided on the outer peripheral surface of the impeller shown in FIG. 1, and is configured to prevent the magnet 3 from scattering.

Here, it has been pointed out that when the magnet 3 for rotatingly driving the impeller is made of ferrite or the like, it is easily broken due to its characteristics. If the fragments of the magnet 3 are scattered and clog in the gap between the impeller and the casing, the impeller locks and the pump including the electric circuit for driving the pump is damaged.

On the other hand, around the magnet 3, the magnet cover 1
By covering with 0, the fragments of the magnet 3 can be prevented from scattering. If the rear shroud 7 and the magnet cover 10 are integrally formed, the magnet cover 10 can be fixed simultaneously with the bonding of the rear shroud 7. Therefore, compared to the case of bonding each with separate parts,
Man-hours can also be reduced.

FIG. 7 is a longitudinal sectional view of an impeller according to an embodiment of the present invention.

As shown in the drawing, the length of the suction side of the front shroud 4 is at least up to the front of the blade 2 as compared with the one shown in FIG. 1, and the inner peripheral surface of the magnet 3 is the fluid on the fixed shaft side. It is exposed to the channel. With such a configuration, the fluid handled by the pump, particularly iron chips contained in tap water, is adsorbed on the inner peripheral surface of the magnet 3. For this reason,
Iron scrap does not enter the gap between the movable part and the non-movable part in the pump, so that deterioration of the pump performance due to wear and damage to the pump due to locking of the impeller can be prevented.

FIG. 8 shows an embodiment of the invention according to claim 8, wherein (a) is an external perspective view of the impeller, and (b) is a longitudinal sectional view.

In this embodiment, the blade 2, the front shroud 4, the bearing holder 5, and the magnet 3 are integrally formed, and are made of a magnetic material. As a material having such a material, there is a so-called plastic magnet in which a magnetic substance such as ferrite is hardened into a fine powder with a resin binder.

With such a configuration, the number of parts can be reduced, so that the cost of the pump can be reduced. Also,
As in the example shown in FIG. 7, iron dust and the like in the fluid can be adsorbed, so that deterioration of the pump performance and breakage of the pump due to the lock of the impeller are prevented.

[0045]

According to the present invention, the number of parts of the impeller is reduced, the positioning of the parts is simplified, the number of assembling steps is reduced, and the assembling accuracy is improved. It is possible to collect foreign substances that adversely affect performance maintenance. Therefore, high efficiency of the pump can be realized at low cost, and the reliability of the pump can be improved.

[Brief description of the drawings]

FIG. 1 is an embodiment of the invention according to claim 1,
(A) is an external view of the impeller. (B) is a longitudinal sectional view taken along line AA of (a).

FIG. 2 is an embodiment of the invention according to claim 2,
(A) is a perspective view of an impeller and a rear shroud (b) is a longitudinal sectional view of the impeller

FIG. 3 is a perspective view of an impeller and a rear shroud showing an embodiment of the invention according to claim 3;

FIG. 4 is a perspective view of an impeller showing an embodiment of the invention according to claim 4;

FIG. 5 is a perspective view of an impeller showing an embodiment of the invention according to claim 5;

FIG. 6 is an embodiment of the invention according to claim 6,
(A) is an external perspective view of the impeller (b) is a longitudinal sectional view

FIG. 7 is a longitudinal sectional view of an impeller showing an embodiment of the invention according to claim 7;

FIG. 8 is an embodiment of the invention according to claim 8,
(A) is an external perspective view of the impeller (b) is a longitudinal sectional view

FIG. 9 is a structural diagram of a conventional pump.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bearing 2 blade 3 magnet 4 front shroud 5 bearing holding portion 6 positioning plate 7 rear shroud 8 welding margin 9 uneven portion 10 magnet cover 11 uneven portion 12 joint surface 101 housing 102 suction flange 103 blade 104 discharge flange 105 rotating shaft 106 bearing 107 Bearing holder 108 Rib 109 Permanent magnet 110 Impeller 111 Stator

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Atsushi Harakawa 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 3H033 AA01 BB08 CC02 CC05 DD01 DD25 DD26 EE05 EE06 EE11 EE19 5H607 AA04 AA12 BB01 CC01 CC05 DD08 FF06 KK03

Claims (8)

[Claims] A housing provided with a fluid suction part and a discharge part and a flow path formed between the suction part and the discharge part; a stator provided around the flow path outside; and the suction part. A fixed shaft having an axis in the direction of the discharge section, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller is free to rotate with respect to the fixed shaft. , A blade arranged around the bearing and pressurizing the fluid flowing from the suction portion by rotation, a front shroud in which a magnet is fixed so as to surround the blade, and the bearing is fixed to the blade. Bearing holding portion, and a positioning plate for positioning the front shroud and the magnet, constitute each part,
A pump having a rotation preventing mechanism that integrally forms the blade, the bearing holding portion, and the front shroud and engages with the magnet to restrict the rotation thereof. 2. A housing having a fluid suction part and a discharge part, and a flow path formed between the suction part and the discharge part, a stator provided outside the flow path, and the suction part. A fixed shaft having an axis in the direction of the discharge section, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller is free to rotate with respect to the fixed shaft. , A blade arranged around the bearing and pressurizing the fluid flowing from the suction portion by rotation, a front shroud arranged around the blade and fixed with a magnet, and And a rear shroud disposed in contact with a rear end of the blade and guiding fluid between the blades, and constitutes each part, and the blade, the bearing holding portion, and the front shroud are formed. Thereby forming the respective parts together, a pump, wherein a central portion of the abutment surface and the conical surface and and the rear shroud between the rear shroud and the blades are contact surface with the bearing. 3. A housing having a fluid suction part and a discharge part, and a flow path formed between the suction part and the discharge part, a stator provided around the flow path, and the suction part. A fixed shaft having an axis in the direction of the discharge section, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller is free to rotate with respect to the fixed shaft. , A blade arranged around the bearing and pressurizing the fluid flowing from the suction portion by rotation, a front shroud arranged around the blade and fixed with a magnet, and And a rear shroud disposed in contact with a rear end of the blade and guiding fluid between the blades, and constitutes each part, and the blade, the bearing holding portion, and the front shroud are formed. Each part is integrally formed, and the contact surface between the blade and the rear shroud is a conical surface, and the front surface of the central portion of the rear shroud and the rear surface of the bearing holding portion are contact surfaces. Pump. 4. The blade and the bearing holder are integrally joined by a welding margin provided on a joint surface between the front shroud and the rear shroud and having an unmelted contact area smaller than the area at the time of joining. 4. The pump according to claim 2, wherein: 5. The blade and the bearing holding portion are provided on a relative position between the front shroud and the rear shroud, and on a contact surface between the bearing holding portion and the rear shroud. The pump according to claim 3, wherein the pump is joined by uneven engagement. 6. A housing provided with a fluid suction part and a discharge part and a flow path formed between the suction part and the discharge part, a stator provided around the flow path outside, and the suction part. A fixed shaft having an axis in the direction of the discharge section, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller is free to rotate with respect to the fixed shaft. A blade disposed around the bearing and pressurizing the fluid flowing from the suction portion by rotation, a front shroud surrounding the blade and having a magnet fixed thereto, and a rear side of the impeller. A rear shroud arranged at an end to guide fluid between the blades in the impeller, and a magnet cover extrapolated around the outer periphery of the magnet, wherein the rear shroud and the magnet cover are integrally formed. Pump to the butterflies. 7. A housing including a fluid suction portion and a discharge portion, a flow passage formed between the suction portion and the discharge portion, a stator provided around the flow passage, and the suction portion. A fixed shaft having an axis in the direction of the discharge section, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller is free to rotate with respect to the fixed shaft. , A blade disposed around the bearing and pressurizing the fluid flowing from the suction portion by rotation, a bearing holding portion for fixing the bearing to the blade, and a magnet disposed so as to surround the blade. And a front shroud to which is fixed, wherein a part of the magnet faces the flow path. 8. A housing having a fluid suction portion and a discharge portion, a flow passage formed between the suction portion and the discharge portion, a stator provided around the flow passage, and a suction device. A fixed shaft having an axis in the direction of the discharge section, and an impeller mounted on the fixed shaft and driven to rotate by energizing the stator, wherein the impeller is free to rotate with respect to the fixed shaft. , A blade disposed around the bearing and pressurizing the fluid flowing from the suction portion by rotation, a bearing holding portion for fixing the bearing to the blade, and a magnet disposed so as to surround the blade. Each part is constituted by the fixed front shroud and
A pump, wherein each part of the front shroud, the bearing holding part, and the blade is integrally formed by a magnet.