Bearing structure for canned motor pump

Abstract

A bearing structure for a shielded electric pump includes: a rotating shaft (2) that rotates integrally with the rotor (12) of a motor unit (11); bearings (3a, 3b) that are embedded in a housing-side bearing housing (32a, 32b) provided in the pump unit (31) via an elastic thin plate (33), supporting the rotating shaft (2) in a vertical direction for free rotation; and bearing-supported members (4a, 4b) that are axially fixed between the rotor (12) of the motor unit (11) and the bearings (3a, 3b). The rotating shaft (2) is axially supported by bearings (3a, 3b) to be rotatable; and the impellers (6a, 6b) rotate integrally with the rotating shaft (2), and in a shielded electric pump (8) in which a portion of the liquid transported due to the rotation of the impellers (6a, 6b) flows between the rotating shaft (2) and the bearings (3a, 3b), an elastic reaction force is imparted axially when the bearings (3a, 3b) are pushed by the bearing-supported members (4a, 4b) to the side opposite to the rotor (12).

Description

Technical Field

[0001] This invention relates to a bearing structure for a shielded electric pump.

[0002] This application claims priority based on Japanese Patent Application No. 2021-094287 filed on June 4, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Previously, it was known that shielded electric pumps used as lubricants had a portion of the pump's supply fluid flow between the rotating shaft and the bearing (see, for example, Patent Document 1).

[0004] The shielded electric pump disclosed in Patent Document 1 includes: a sliding bearing (hereinafter referred to as a "radial bearing") that supports a rotating shaft in a direction perpendicular to the axial direction, and a sliding bearing (hereinafter referred to as an "axial bearing") fixed to the rotating shaft. The axial bearing restricts the axial movement of the rotating shaft by having its contact surface contact the side of the radial bearing in the axial direction.

[0005] A certain gap is provided between the rotating shaft and the radial bearing to allow a portion of the pump's fluid supply to flow. Furthermore, although not described in Patent Document 1, in many cases, the radial bearing is embedded in the bearing housing through a thin, elastic sheet such as a tolerance ring.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 3897931 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In the bearing structure of the aforementioned canned motor pump, due to the influence of dimensional tolerances, there are instances where the side surface of the radial bearing and the contact surface of the axial bearing do not make surface contact when they are relatively inclined and in contact with each other. In this case, local wear progresses on the side surface of the radial bearing and the contact surface of the axial bearing, the initial axial clearance of the rotating shaft and the inclination of the rotating shaft relative to the initial axial direction gradually increase, and the pump performance may decrease.

[0011] The present invention was first developed in view of the above-mentioned problems, with the aim of providing a bearing structure for a shielded electric pump configured such that, for a shielded electric pump in which a portion of the supplied fluid is used as a lubricant between a rotating shaft and a bearing (radial bearing) that supports the rotating shaft in a direction perpendicular to the axial direction, the side surface of the bearing (radial bearing) and the abutting surface of the bearing-supported member (axial bearing) fixed to the rotating shaft in the axial direction can easily make surface contact with each other.

[0012] Solution for solving the problem

[0013] The bearing structure of the canned motor pump according to the first aspect of the present invention is based on the following: a rotating shaft that rotates integrally with the rotor of the motor unit; a bearing that is embedded in a housing-side bearing shell provided in the pump unit through an elastic thin plate, supporting the rotating shaft to be rotatable in a direction perpendicular to the axial direction; a bearing-supported member that is mounted on the rotating shaft between the rotor of the motor unit and the bearing, and is supported axially by the bearing to be rotatable; and an impeller that rotates integrally with the rotating shaft, wherein a portion of the liquid transported due to the rotation of the impeller flows between the rotating shaft and the bearing. The bearing structure of the canned motor pump is characterized by having the following elastic structure: when the bearing is pushed by the bearing-supported member to the side opposite to the rotor of the motor unit, an elastic reaction force is imparted axially to one or both of the bearing and the bearing-supported member.

[0014] The bearing structure of the shielded electric pump of the second aspect of the present invention is based on the bearing structure of the shielded electric pump of the first aspect, wherein the elastic structure imparts the elastic reaction force to the bearing in the axial direction, and is an elastic body provided between the bearing on the side opposite to the rotor of the motor part and the bearing housing on the housing side.

[0015] The bearing structure of the third aspect of the shielded electric pump of the present invention is based on the bearing structure of the first aspect of the shielded electric pump, wherein the bearing-supported member is mounted on the rotating shaft by means of a housing for the bearing-supported member. The elastic structure, which imparts the elastic reaction force to the bearing-supported member in the axial direction, is an elastic body provided between the housing for the bearing-supported member and the side of the bearing-supported member near the rotor of the motor portion.

[0016] The bearing structure of the fourth aspect of the shielded electric pump of the present invention is based on the bearing structure of the first aspect of the shielded electric pump, wherein, in the elastic structure, a plate is provided between the side of the bearing opposite to the rotor of the motor part and the housing-side bearing housing. The housing-side bearing housing axially supports only a portion of the side of the plate opposite to the bearing, thereby imparting the elastic reaction force to the bearing in the axial direction.

[0017] The bearing structure of the fifth aspect of the shielded electric pump of the present invention is based on the bearing structure of the first aspect of the shielded electric pump, wherein the bearing-supported member is axially fixed to the rotating shaft by means of a bearing-supported member housing. In the elastic structure, a plate is provided between the rotor side of the bearing-supported member near the motor portion and the bearing-supported member housing, and the bearing-supported member housing axially supports only a portion of the side of the plate opposite to the bearing-supported member, thereby imparting the elastic reaction force to the bearing-supported member in the axial direction.

[0018] The effects of the invention

[0019] According to the present invention, the bearing and the component supported by the bearing can easily make surface contact with each other. Attached Figure Description

[0020] Figure 1 This is a partial cross-sectional view of the shielded electric pump of this embodiment.

[0021] Figure 2 This is an enlarged cross-sectional view of the periphery of the first bearing in this embodiment.

[0022] Figure 3 yes Figure 1 Enlarged view of part A.

[0023] Figure 4 yes Figure 1 Enlarged view of part B.

[0024] Figure 5 This is an enlarged cross-sectional view of the periphery of the connecting pipe in another embodiment.

[0025] Figure 6 This is an enlarged cross-sectional view of the periphery of the elastic structure in another embodiment.

[0026] Figure 7 This is an enlarged cross-sectional view of the periphery of the elastic structure in this embodiment.

[0027] Figure 8 This is an enlarged cross-sectional view of the periphery of the elastic structure in another embodiment.

[0028] Figure 9 This is an enlarged cross-sectional view of the periphery of the elastic structure in this embodiment. Detailed Implementation

[0029] Hereinafter, with reference to the accompanying drawings, the bearing structure of the shielded electric pump according to an embodiment of the present invention will be described. Figures 1-4As shown, the bearing structure 1 of the canned electric pump consists of a rotating shaft 2 included in the canned electric pump 8, bearings 3a and 3b, bearing-supported components 4a and 4b, impellers 6a and 6b, and an elastic structure 7.

[0030] like Figure 1 As shown, the canned motor pump 8 includes a motor section 11 and a pump section 31 driven by the motor section 11. The motor section 11 is a canned motor consisting of a rotor 12 with a magnet 27 and a stator 13 on the outer periphery of the rotor 12. The rotating shaft 2, on which the rotor 12 is fixed, is supported by a sleeve 25 on bearings 3a and 3b mounted on bearing housings 32a and 32b on the housing side. The pump section 31 includes impellers 6a and 6b, which are fixed to the rotating shaft 2; and pump housings 16a and 16b, which have impeller housing spaces 14a and 14b for housing the impellers 6a and 6b. The rotor 12 of the motor section 11 is housed inside the stator shielding sleeve 9. The stator 13 of the motor section 11 is housed between the outer peripheral surface 17 of the stator shielding sleeve 9 and the inner peripheral surface 19 of the cylindrical motor frame 18 at a position corresponding to the rotor 12 inside the stator shielding sleeve 9. The motor frame 18 houses a stator shielding sleeve 9. The stator shielding sleeve 9 is welded to the stator side plates 10 located at both ends of the motor frame 18. The motor frame 18 and the stator side plates 10 located at both ends of the motor frame 18 are sealed by O-rings 5 ​​and are also sealed by partial welding. The stator side plates 10 and the housing-side bearing housings 32a and 32b are sealed using O-rings 15 located at both ends of the stator side plates 10 to form an internal space 66. The pump housings 16a and 16b, and the housing-side bearing housings 32a and 32b are sealed using O-rings 20 located at both ends of the housing-side bearing housings 32a and 32b to form impeller housing spaces 14a and 14b. Furthermore, a small gap is formed between the inner circumferential surfaces of the bearings 3a and 3b and the sleeve 25, allowing the bearings 3a and 3b to tilt at a small angle relative to the axis. Hereinafter, pump housing 16a will be referred to as "first pump housing 16a" and pump housing 16b will be referred to as "second pump housing 16b".

[0031] Furthermore, the portion of the outer peripheral surface 17 of the stator shielding sleeve 9 where the stator core 21 is not located is covered by the support cylinder 22. The support cylinder 22 has a cylindrical shape along the outer peripheral surface 17 of the stator shielding sleeve 9.

[0032] The motor unit 11 includes a rotor 12 and a stator 13. The rotor 12 is composed of a rotor shielding sleeve 23, a rotor side plate 24, a rotor body 26, a magnet 27, a magnetic yoke 28, etc. The rotor 12 is fixed to the rotating shaft 2 in a manner that allows it to rotate integrally with the rotating shaft 2. The rotating shaft 2 is supported by a sleeve 25 on bearings 3a and 3b mounted on bearing housings 32a and 32b on the housing side. The rotor 12 includes a rotor body 26 fixed relative to the rotating shaft 2 and a magnetic yoke 28, a magnet 27, a rotor side plate 24, and a rotor shielding sleeve 23 supported on the rotor body 26. The rotor shielding sleeve 23 is welded to the rotor body 26 and the rotor side plate 24 to seal the magnet 27 and the magnetic yoke 28. The rotor 12 is housed inside the stator shielding sleeve 9 in the canned motor pump 8.

[0033] The stator 13 is composed of electromagnetic coils 29, etc. If a driving current is supplied to the stator 13, the rotor 12 and the rotating shaft 2 will be driven to rotate.

[0034] The rotating shaft 2 is fixed with the rotor 12 of the motor unit 11 and rotates integrally with the rotor 12 of the motor unit 11.

[0035] like Figures 1-4 As shown, bearings 3a and 3b are embedded in the housing-side bearing housings 32a and 32b of the pump section 31 via a thin elastic plate 33. Bearings 3a and 3b support the rotating shaft 2 in a direction perpendicular to the axial direction, allowing for free rotation. Bearings 3a and 3b are cylindrical. On bearings 3a and 3b, a groove 76 extending in the radial direction is formed on the axial end face 34, and a spiral groove 74 is formed on the inner peripheral wall 36. Both grooves 74 and 76 are provided to facilitate liquid flow. For example, SiC (silicon carbide), which has excellent heat resistance and durability, is used as the material for bearings 3a and 3b.

[0036] In this embodiment, bearings 3a and 3b are disposed on the outer periphery of sleeve 25, which is a component of the rotating shaft 2. The sleeve 25 is also made of a material with excellent heat resistance and durability, just like bearings 3a and 3b.

[0037] Bearings 3a and 3b are disposed on both sides of the rotor 12 of the motor section 11 in the axial direction of the rotating shaft 2. Hereinafter, bearing 3a will be referred to as "first bearing 3a" and bearing 3b will be referred to as "second bearing 3b".

[0038] Bearings 3a and 3b are embedded in the bearing housings 32a and 32b on the housing side. The bearing housings 32a and 32b on the housing side are disposed in the pump section 31.

[0039] The housing-side bearing housings 32a and 32b are disposed on both sides of the rotor 12 of the motor section 11 in the axial direction of the rotating shaft 2. Hereinafter, the two housing-side housings 32 will be referred to as "first housing-side bearing housing 32a" and "second housing-side bearing housing 32b", respectively.

[0040] In this embodiment, a tolerance ring is used as the elastic thin plate 33. Bearings 3a and 3b are embedded in the housing-side bearing housings 32a and 32b through the elastic thin plate 33, thereby preventing the bearings 3a and 3b from shaking relative to the housing-side bearing housings 32a and 32b and absorbing the difference in the coefficients of thermal expansion between the housing-side bearing housings 32a and 32b and the bearings 3a and 3b.

[0041] The rotating shaft 2 and rotor 12 are provided with bearing support member housings 38a and 38b, which house bearing support members 4a and 4b, respectively. The bearing support members 4a and 4b are embedded in the bearing support member housings 38a and 38b via a thin elastic sheet 35. In this embodiment, a tolerance ring is also used for the thin elastic sheet 35. The bearing support member housings 38a and 38b are axially fixed relative to the rotating shaft 2. The bearing support members 4a and 4b are mounted on the rotating shaft 2 via the bearing support member housings 38a and 38b. Therefore, the rotating shaft 2 is axially supported by the bearings 3a and 3b via the bearing support members 4a, 4b, and the bearing support member housings 38a and 38b. Furthermore, a predetermined gap is formed between the inner circumferential surfaces of the bearing support members 4a and 4b and the housings 38a and 38b of the bearing support members, allowing the bearing support members 4a and 4b to tilt at a small angle relative to the axis.

[0042] Bearing support members 4a and 4b are also provided on both sides of the rotor 12 of the motor unit 11 in the axial direction of the rotating shaft 2. Specifically, the bearing support members 4a and 4b are mounted on the rotating shaft 2 between the rotor 12 of the motor unit 11 and the bearings 3a and 3b, and are axially supported by the bearings 3a and 3b to allow for free rotation. As the material for the bearing support members 4a and 4b, SiC, which has excellent heat resistance and durability, is used.

[0043] Hereinafter, the bearing-supported member 4a supported on the first bearing 3a will be referred to as the "first bearing-supported member 4a", and the bearing-supported member 4b supported on the second bearing 3b will be referred to as the "second bearing-supported member 4b".

[0044] Impellers 6a and 6b rotate integrally with the rotating shaft 2. For example... Figure 2 and Figure 4 As shown, impellers 6a and 6b include: cylindrical impeller hub portions 39a and 39b, which are fixed to the rotating shaft 2; and annular plate-shaped impeller blade portions 45a and 45b, which are connected to the impeller hub portions 39a and 39b. The impeller hub portions 39a and 39b include: a rotating shaft fixing portion 47, which is cylindrical and fixes the impeller hub portions 39a and 39b to the rotating shaft 2; and an impeller blade connecting portion 48, which extends from the outer circumferential surface of the rotating shaft fixing portion 47 along the radial direction of the rotating shaft fixing portion 47, is annular plate-shaped, and is connected to the impeller blade portions 45a and 45b. Impeller hub portions 39a and 39b are connected to the rotation center side end 46 of impeller blade portions 45a and 45b at the impeller blade connection portion 48. Impeller hub portions 39a and 39b have axially penetrating impeller hub through holes 49a and 49b at the impeller blade connection portion 48. Liquid flowing back from the stator shield sleeve 9 side passes through these impeller hub through holes 49a and 49b. Furthermore, impeller hub portions 39a and 39b are provided with annular impeller hub protrusions 51a and 51b extending towards the stator shield sleeve 9 side to prevent backflow of liquid. Impeller hub protrusions 51a and 51b are inserted into annular recesses 53a and 53b formed on the inner wall surfaces 52 of pump housings 16a and 16b.

[0045] In the shielded electric pump 8 of this embodiment, one impeller 6a and one impeller 6b are provided at each of the two axial ends of the stator shielding sleeve 9. Hereinafter, impeller 6a will be referred to as "first impeller 6a" and impeller 6b will be referred to as "second impeller 6b".

[0046] A first inlet 56 is provided on the side of the first pump casing 16a, which houses the first impeller 6a. In addition, a liquid supply port 57 is provided on the upper surface of the first pump casing 16a to supply liquid that has flowed into the first pump casing 16a to the second pump casing 16b.

[0047] The bearing housing 32a on the first housing side has a first communication path 67 connecting the first impeller housing space 14a and the internal space 66 of the stator shield sleeve 9. The opening 64 of the first communication path 67 is located on the wall 63 of the first impeller housing space 14a on the side near the stator shield sleeve 9, and is located near the through hole 49a of the first impeller hub, closer to the rotating shaft 2 than the first impeller hub protrusion 51a.

[0048] The first housing-side bearing housing 32a and the first pump housing 16a together form the first impeller housing space 14a. The first housing-side bearing housing 32a has a first recess 53a on the wall surface 63 on the side of the first impeller housing space 14a near the stator shield sleeve 9. A first impeller hub protrusion 51a provided in the first impeller hub portion 39a is inserted into the first recess 53a.

[0049] Additionally, a cylindrical first sealing plate 78, coaxial with the rotation shaft 2, is provided on the first impeller blade 45a. The first sealing plate 78 extends axially toward the first inlet 56 from the rotation shaft 2, reducing the gap between its outer circumferential surface and the inner wall 77 of the first inlet 56 in the first pump casing 16a. The first sealing plate 78 blocks the space in the first inlet 56 from the space formed by the outer wall 79 of the first impeller blade 45a on the side adjacent to the first sealing plate 78 and the inner wall 54 of the first pump casing 16a.

[0050] like Figure 4 As shown, the second impeller 6b, which is another impeller, includes: a second impeller hub portion 39b, which is fixed to the rotating shaft 2; and a second impeller blade portion 45b, which is connected to the second impeller hub portion 39b. An annular second impeller hub portion protrusion 51b extending in the axial direction toward the stator shield sleeve 9 is provided on the second impeller hub portion 39b.

[0051] A second inlet 58 is provided on the side of the second pump casing 16b, which houses the second impeller 6b. The second inlet 58 is cylindrical with a central axis coaxial with the rotating shaft 2, allowing liquid delivered from the first impeller 6a to flow in. In addition, an outlet 61 is provided on the upper surface of the second pump casing 16b to spray out the liquid that has flowed into the second pump casing 16b.

[0052] The bearing housing 32b on the second housing side has a second communication path 71 connecting the internal space 66 of the second impeller housing space 14b and the stator shield sleeve 9. The opening 69 of the second communication path 71 is located on the wall 68 of the second impeller housing space 14b on the side near the stator shield sleeve 9, and is located near the through hole 49b of the second impeller hub, closer to the rotating shaft 2 than the protrusion 51b of the second impeller hub.

[0053] The second housing-side bearing housing 32b, together with the second pump housing 16b, forms the second impeller housing 14b. The second housing-side bearing housing 32b has a second recess 53b on the wall 68 of the side forming the second impeller housing 14b near the stator shield 9. A second impeller hub protrusion 51b, provided on the second impeller hub portion 39b, is inserted into the second recess 53b.

[0054] Additionally, a cylindrical second sealing plate 82, coaxial with the rotation shaft 2, is provided on the second impeller blade 45b. The second sealing plate 82 extends axially toward the second inlet 58 from the rotation shaft 2, reducing the gap between its outer circumferential surface and the inner wall 81 of the second inlet 58 in the second pump casing 16b. The second sealing plate 82 blocks the space in the second inlet 58 from the space formed by the outer wall 83 of the second impeller blade 45b on the side adjacent to the second sealing plate 82 and the inner wall 59 of the second pump casing 16b.

[0055] The first pump casing 16a and the second pump casing 16b are connected by a connecting pipe 62 that forms a flow path for conveying liquid from the first impeller 6a to the second impeller 6b. The connecting pipe 62 passes through the outside of the motor frame 18 and conveys the liquid ejected from the liquid supply port 57 of the first pump casing 16a to the second inlet 58 of the second pump casing 16b.

[0056] In the shielded electric pump 8 of this embodiment, such as Figure 3 and Figure 4 As shown, a portion of the liquid transported by the rotation of impellers 6a and 6b flows between the rotating shaft 2 and bearings 3a and 3b as indicated by the double-dotted arrow.

[0057] Liquid flowing into the first pump casing 16a from the first inlet 56 is propelled by the rotational force of the first impeller 6a through the flow path 72 inside the first impeller blade of the first impeller 6a, passes through the connecting pipe 62, and flows into the second pump casing 16b from the second inlet 58.

[0058] The liquid flowing into the second pump casing 16b branches into two directions. The liquid from one branch is ejected from the nozzle 61 outward from the second pump casing 16b through the internal flow path 73 of the second impeller 6b by the rotational force of the second impeller 6b. The liquid from the other branch is transported into the stator shield sleeve 9 through the through hole 49b of the second impeller hub of the second impeller 6b.

[0059] The liquid delivered from the second pump housing 16b to the stator shield 9 further branches into two directions. The liquid on one branch passes through the space between the stator shield 9 and the rotor 12 towards the first bearing 3a via the second connecting path 71 provided in the second pump housing 16b. The liquid on the other branch passes between the sleeve 25 of the rotating shaft 2 and the second bearing 3b.

[0060] The liquid that passes between the sleeve 25 of the rotating shaft 2 and the second bearing 3b passes between the second bearing 3b and the second supported member 4b, and flows in the space between the stator shield 9 and the rotor 12 toward the first bearing 3a. When the liquid passes between the sleeve 25 of the rotating shaft 2 and the second bearing 3b, and when the liquid passes between the second bearing 3b and the second supported member 4b, the liquid mainly passes through the grooves 76 and 74 formed in the second bearing 3b. When the liquid passes between the sleeve 25 of the rotating shaft 2 and the second bearing 3b, and between the second bearing 3b and the second supported member 4b, the liquid becomes a lubricant between the sleeve 25 of the rotating shaft 2 and the second bearing 3b, and between the second bearing 3b and the second supported member 4b.

[0061] The liquid passing through the space between the stator shield sleeve 9 and the rotor 12 branches into two directions. Liquid on one side enters the first impeller blade inner flow path 72 of the first impeller 6a through the first connecting path 67 of the first pump casing 16a and the first impeller hub through hole 49a of the first impeller hub 39a. Liquid on the other side passes between the first bearing 3a and the first bearing-supported member 4a, and between the first bearing 3a and the sleeve 25 of the rotating shaft 2. When liquid passes between the first bearing 3a and the first bearing-supported member 4a, and when liquid passes between the first bearing 3a and the sleeve 25 of the rotating shaft 2, the liquid mainly passes through the grooves 74 and 76 formed in the first bearing 3a. When the liquid passes between the first bearing 3a and the first supported member 4a, and between the first bearing 3a and the sleeve 25 of the rotating shaft 2, the liquid becomes a lubricant between the first bearing 3a and the first supported member 4a, and between the first bearing 3a and the sleeve 25 of the rotating shaft 2. The liquid that has passed between the first bearing 3a and the sleeve 25 of the rotating shaft 2 enters the inner flow path 72 of the first impeller 6a through the first impeller hub through hole 49a of the first impeller hub 39a.

[0062] like Figure 5 As shown, the first pump housing 16a and the connecting pipe 62 are connected by a first ejection flow path 84 provided on the secondary side of the liquid supply port 57 on the upper surface of the first pump housing 16a. The first ejection flow path 84 and the connecting pipe 62 are connected by bolts to fasten flanges 86 and 87 respectively provided at opposite ends.

[0063] The second pump casing 16b and the connecting pipe 62 are connected by a second suction flow path 88 provided on the primary side of the second inlet 58 of the second pump casing 16b. The second suction flow path 88 and the connecting pipe 62 are connected by bolts to fasten flanges 89 and 91, which are respectively provided at opposite ends of each other.

[0064] like Figure 6 , Figure 7 as well as Figure 8 As shown, when the bearings 3a and 3b are pushed by the bearing support members 4a and 4b toward the side opposite to the rotor 12 of the motor unit 11, the elastic structure 7 (7A, 7B and 7C) imparts an elastic reaction force to one or both of the bearings 3a and 3b and the bearing support members 4a and 4b in the axial direction.

[0065] The rotating shaft 2 moves towards the first impeller 6a by an amount corresponding to the clearance due to the axial pressure difference, and bearings 3a and 3b push against each other axially with the bearing-supported members 4a and 4b. Even if there are dimensional errors in the inner circumferential surfaces of the bearing-supported member housings 38a and 38b and the inner circumferential surfaces of the housing-side bearing housings 32a and 32b, due to the elastic structure 7, bearings 3a and 3b and / or bearing-supported members 4a and 4b abut against each other with their opposing surfaces in a surface-to-surface contact manner while being tilted at a small angle relative to the axial direction. Thus, the surface contact between bearings 3a and 3b and bearing-supported members 4a and 4b prevents wear caused by unilateral contact between bearings 3a and 3b and bearing-supported members 4a and 4b.

[0066] Figure 6 Examples of elastic structures 7B include one consisting of an elastic body disposed between the bearing 3a on the side opposite to the rotor 12 of the motor section 11 and the bearing housing 32a on the housing side; and another example where the elastic structure 7B is disposed between the housing 38a of the bearing support member and the side of the bearing support member 4a facing the rotor 12 of the motor section 11. Figure 6 The elastic body shown is a helical spring. The diameter of the helical spring is the same as or smaller than the radial thickness of the bearing 3a and the bearing-supported member 4a. Furthermore, multiple helical springs are arranged at certain intervals along the circumference of both the bearing 3a and the bearing-supported member 4a. In addition, Figure 6 Only the elastic structure 7B on the first impeller 6a side is shown; the illustration of the elastic structure 7B on the second impeller 6b side is omitted. The elastic structure 7B on the second impeller 6b side (not shown) has a structure that is axially symmetrical to the elastic structure 7B on the first impeller 6a side with respect to the rotor 12.

[0067] Figure 8 The elastic structure 7C shown is in the form of... Figure 6In the example shown, the multiple helical springs constituting the elastic structure 7B are replaced by a single helical spring. The helical spring constituting the elastic structure 7C is arranged concentrically with the rotation shaft 2. Figure 8 The helical springs press against the radial center of the end faces of bearings 3a and 3b, and the bearing-supported members 4a and 4b. Furthermore, Figure 8 Only the elastic structure 7C on the side of the first impeller 6a is shown; the illustration of the elastic structure 7C on the side of the second impeller 6b is omitted. The elastic structure 7C on the side of the second impeller 6b (not shown) has a structure that is axially symmetrical to the elastic structure 7C on the side of the first impeller 6a with the rotor 12 as the center.

[0068] In addition, spring washers, disc spring washers, wave washers, etc., can be used to replace the helical springs that constitute the elastic structure 7B and the elastic structure 7C.

[0069] exist Figure 7 In the elastic structure 7A, a plate 92 is provided between the side of the bearing 3a opposite to the rotor 12 of the motor part 11 and the housing-side bearing housing 32a. The housing-side bearing housing 32a only partially supports the side of the plate 92 opposite to the bearing 3a in the axial direction, thereby imparting an elastic reaction force to the bearing 3a in the axial direction. The plate 92 can be, for example, a thin metal plate, or a metal gasket. In this case, a bearing-side clearance 93 is formed between the housing-side bearing housing 32a and the plate 92. Furthermore, in... Figure 7 The bending of plate 92 and the tilting of bearing 3a and the bearing-supported member 4a are emphasized. Furthermore, Figure 7 This only indicates the elastic structure 7A on the side of the first impeller 6a. For example... Figure 2 As shown, the elastic structure 7A on the side of the second impeller 6b has a structure that is symmetrical about the rotor 12 in the axial direction to the elastic structure 7A on the side of the first impeller 6a.

[0070] In this embodiment, the bearing side clearance 93 is formed on one side of the inner diameter of the plate 92, and the outer diameter of the plate 92 is held by bearings 3a and 3b and housing-side bearing housings 32a and 32b. The bearing side clearance 93 is formed only on one side of the inner diameter of the plate 92, so that when bearings 3a and 3b are tilted relative to the rotation shaft 2, the plate 92 flexes towards the bearing side clearance 93, generating an elastic force.

[0071] In addition, Figure 7As a further elastic structure 7D, the following elastic structure is shown: a plate 92 is provided between the side of the bearing-supported member 4a near the rotor 12 of the motor part 11 and the housing 38a of the bearing-supported member. The housing 38a of the bearing-supported member supports only a portion of the side of the plate 92 opposite to the bearing-supported member 4a in the axial direction, thereby imparting an elastic reaction force to the bearing-supported member 4a in the axial direction. Here, the plate 92 can also be a thin plate of metal, such as a metal gasket, etc., and a bearing-supported member side gap 94 is formed between the housing 38a of the bearing-supported member and the plate 92. Furthermore, Figure 7 This only indicates the elastic structure 7D on the side of the first impeller 6a. For example... Figure 4 As shown, the elastic structure 7D on the second impeller 6b side has a structure that is symmetrical about the rotor 12 in the axial direction to the elastic structure 7D on the first impeller 6a side.

[0072] In this embodiment, the bearing support member side clearance 94 is formed on one side of the outer diameter of the plate 92, and the inner diameter of the plate 92 is held by the bearing support member 4a, the bearing support member 4b, and the bearing support member housing 38a and the bearing support member housing 38b. The bearing support member side clearance 94 is formed only on one side of the outer diameter of the plate 92, so that when the bearing support member 4a and the bearing support member 4b are tilted relative to the rotation axis 2, the plate 92 flexes towards the bearing support member side clearance 94, generating an elastic force.

[0073] Figure 9 This diagram shows the bearing 3a and the bearing-supported member 4a in surface contact with each other at a slight inclination relative to the rotation axis 2. However, only the bending of the plate 92 is emphasized, and the inclination of the bearing 3a and the bearing-supported member 4a is not emphasized.

[0074] Plate 92 can flex at any position in the circumferential direction towards the bearing side clearance 93 or the bearing-supported member side clearance 94. Therefore, if bearings 3a and 3b are pushed axially towards the bearing-supported members 4a and 4b without surface contact, then... Figure 9 As shown, while bearings 3a and 3b and the bearing-supported members 4a and 4b are tilted relative to the axial direction, the plate 92 partially deflects towards the bearing side clearance 93 or the bearing-supported member side clearance 94. As a result, bearings 3a and 3b and the bearing-supported members 4a and 4b make surface contact with each other. Furthermore, in Figure 9In the example shown, the outer diameter side of the upper part of the bearing support member 4a pushes the plate 92 toward the bearing support member side gap 94, and the inner diameter side of the upper part of the bearing 3a pushes the plate 92 toward the bearing side gap 93. Therefore, each plate 92 flexes.

[0075] As a variation of the above embodiment, in the above embodiment, the plate 92 may be disposed only between the bearing 3a, the bearing 3b and the housing-side bearing housing 32a, the housing-side bearing housing 32b, the bearing-supported member 4a, the bearing-supported member 4b and the bearing-supported member housing 38a, the bearing-supported member housing 38b.

[0076] This invention can be implemented in various other ways without departing from its spirit, purpose, or main features. Therefore, the above-described embodiments are merely illustrative in all respects and are not intended to be limiting.

[0077] Industrial availability

[0078] This invention can be applied, for example, to shielded electric pumps.

[0079] Explanation of reference numerals in the attached figures

[0080] 1. Bearing structure of the canned motor pump; 2. Rotating shaft; 3a, 3b. Bearing; 4a, 4b. Bearing-supported components; 6a, 6b. Impeller; 7A, 7B, 7C, 7D. Elastic structure; 8. Canned motor pump; 11. Motor section; 12. Rotor; 31. Pump section; 32a, 32b. Bearing housing on the casing side; 33. Elastic thin sheet metal; 38a, 38b. Housing for bearing-supported components; 92. Sheet metal.

Claims

1. A bearing structure for a canned electric pump, characterized in that, The bearing structure of the shielded electric pump includes: A rotating shaft that rotates integrally with the rotor of the motor unit; The bearing, which is embedded in the housing side bearing housing provided in the pump section through a thin elastic plate, supports the rotating shaft in a direction perpendicular to the axial direction so that it can rotate freely; A bearing-supported member, mounted on the rotating shaft between the rotor of the motor and the bearing, and axially supported by the bearing for free rotation; and The impeller rotates integrally with the rotating shaft. The bearing-supported member is embedded in the bearing-supported member housing, which is fixed relative to the rotation axis, through an elastic thin plate. A predetermined gap is formed between the inner circumferential surface of the bearing-supported member and the bearing-supported member housing. In a shielded electric pump, a portion of the liquid transported due to the rotation of the impeller flows between the rotating shaft and the bearing. The bearing structure of the shielded electric pump has the following elastic structure: when the bearing is pushed by the bearing-supported member to the side opposite to the rotor of the motor, an elastic reaction force is applied axially to one or both of the bearing and the bearing-supported member.

2. The bearing structure of the shielded electric pump according to claim 1, characterized in that, The elastic structure, which imparts the elastic reaction force to the bearing in the axial direction, is an elastic body disposed between the bearing on the side opposite to the rotor side of the motor section and the bearing housing on the housing side.

3. The bearing structure of the shielded electric pump according to claim 1, characterized in that, The elastic structure, which imparts the elastic reaction force to the bearing-supported member in the axial direction, is an elastic body disposed between the housing of the bearing-supported member and the side of the bearing-supported member near the rotor of the motor portion.

4. The bearing structure of the shielded electric pump according to claim 1, characterized in that, In the elastic structure, A plate is provided between the bearing and the bearing housing on the side opposite to the rotor side of the motor section. The outer peripheral side of the face opposite to the bearing side of the plate is supported axially by the housing-side bearing housing, and a bearing-side clearance is formed between the inner peripheral side of this face and the housing-side bearing housing, thereby imparting the elastic reaction force to the bearing in the axial direction.

5. The bearing structure of the shielded electric pump according to claim 1, characterized in that, In the elastic structure, A plate is provided between the rotor side of the bearing-supported member near the motor part and the housing of the bearing-supported member. The inner circumferential side of the surface of the plate opposite to the side of the bearing-supported member is supported axially by the housing of the bearing-supported member, and a gap is formed between the outer circumferential side of the surface and the housing of the bearing-supported member, thereby imparting the elastic reaction force to the bearing-supported member in the axial direction.

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