Canned motor pump

Abstract

According to the present invention, disconnection of a lead wire due to expansion and contraction of a coil end can be prevented.　A canned motor pump 1 according to the present invention includes: a motor bearing wear monitoring device 5 that monitors a wear state of a bearing; a rotor 34; a stator 35; a rotary shaft 31; a bearing 32; a can 36; a plurality of detection coils C that detect a magnetic flux change corresponding to a mechanical position change of the rotor with respect to the stator; a lead wire L wired between the detection coils and the motor bearing wear monitoring device; and a protective sheet S protecting the lead wire. The stator includes a stator core 351 and a plurality of conducting wires 352. In the axial direction of the rotary shaft, a part of each of the plurality of conducting wires protrudes from the stator core to form an annular coil end 353. A part of the lead wire is wired along the inner circumferential surface 354 of the coil end. The protective sheet is disposed between the inner circumferential surface and the lead wire.

Description

canned motor pump

[0001] The present invention relates to a canned motor pump.

[0002] Canned motor pumps, which integrate the pump and motor and prevent leakage of pumped fluid, are known. A canned motor pump has a structure in which the rotating structural parts (rotor, rotating shaft, and bearings) are sealed in a can filled with pumped fluid. Therefore, canned motor pumps have the problem of "difficulty in monitoring the condition of the rotating structural parts." To address this issue, canned motor pumps use a device to monitor the wear condition of the bearings (see, for example, Patent Document 1).

[0003] The device disclosed in Patent Document 1 includes four detection coils arranged at both ends of the stator in the longitudinal direction of the stator. This device measures magnetic flux changes corresponding to changes in the rotor's position relative to the stator based on detection signals output from each detection coil. The stator includes a cylindrical stator core and multiple conductors attached to the stator core. A portion of each of the multiple conductors protrudes from an end of the stator core in the longitudinal direction of the stator. The multiple protruding conductors form annular coil ends. Meanwhile, the detection coil is arranged at an end of the stator core in the longitudinal direction of the stator core. The detection coil is connected to a device that monitors the wear state of the bearing via lead wires. The lead wires are routed along the inner circumferential surface of the annular coil ends.

[0004] In a canned motor pump, when the canned motor pump is operating, the stator generates a rotating magnetic field, generating heat that causes the coil ends to become hot. As a result, the coil ends expand. Furthermore, when the canned motor pump is stopped or its output is reduced, the temperature of the coil ends drops, causing the coil ends to contract. In this way, the coil ends repeatedly expand and contract depending on the operation of the canned motor pump.

[0005] Japanese Patent Application Publication No. 10-080103

[0006] When the coil end expands, the overall volume of the coil end increases, and the inner circumferential surface of the coil end also expands. As a result, the lead wire is pulled in the circumferential direction of the coil end due to the expansion of the inner circumferential surface of the coil end. In other words, tension is applied to the lead wire along its longitudinal direction. As a result, the lead wire may break.

[0007] Furthermore, repeated expansion and contraction of the coil ends can cause gaps to form between the conductors. If a portion of the lead wire becomes caught in this gap, that portion is pressed from both sides of the lead wire by the expansion of the coil ends. In other words, tension is applied to the lead wire by the pressing force caused by the expansion of the coil ends. As a result, the lead wire may break.

[0008] The present invention aims to prevent breakage of lead wires due to expansion and contraction of coil ends.

[0009] In one embodiment of the present invention, a canned motor pump comprises a rotor, a stator that rotates the rotor, a rotating shaft that rotates with the rotor, a bearing that supports the rotating shaft, a cylindrical can that accommodates the rotor, the rotating shaft, and the bearing, a plurality of detection coils that detect magnetic flux changes corresponding to mechanical position changes of the rotor relative to the stator, a motor bearing wear monitoring device that monitors the wear state of the bearing based on detection signals output from each of the plurality of detection coils, lead wires wired between the detection coils and the motor bearing wear monitoring device, and a protective sheet that protects the lead wires, wherein the stator comprises a stator core and a plurality of conducting wires attached to the stator core, a portion of each of the plurality of conducting wires protruding from the stator core in the axial direction of the rotating shaft to form annular coil ends, a portion of the lead wires being wired along the inner surface of the coil end, and the protective sheet is arranged between the inner surface and the lead wires.

[0010] According to the present invention, breakage of the lead wire due to expansion and contraction of the coil end can be prevented.

[0011] 1 is a side view of a canned motor pump showing an embodiment of the canned motor pump according to the present invention; FIG. 2 is a schematic cross-sectional view of a motor section included in the canned motor pump of FIG. 1, showing a longitudinal cross section of the motor section; FIG. 3 is a perspective view of a stator included in the canned motor pump of FIG. 1; FIG. 4 is an enlarged perspective view of a stator core showing an enlarged tooth section on which a detection coil is arranged in the stator of FIG. 3; FIG. 5 is a schematic perspective view of a stator core showing the arrangement of a detection coil in the stator of FIG. 3; FIG. 6 is an enlarged cross-sectional view of a coil end showing an enlarged section A of FIG. 2; FIG. 7 is a partial developed view of the coil end of the stator of FIG. 3, showing a state in which lead wires are wired on the inner circumferential surface of the coil end; FIG. 8 is a schematic side view of the coil end of FIG. 8, showing a state in which a protection sheet is arranged on the inner circumferential surface of the coil end; FIG. 9 is a schematic side view of the coil end of FIG. 9, showing a state in which a protection sheet is arranged on the inner circumferential surface of the coil end. 12 is a schematic side view of the coil end of FIG. 11 , showing the coil end tied with a string. FIG. 13 is an enlarged cross-sectional view of the coil end, showing a modified example of the stator provided in the canned motor pump according to the present invention. FIG. 14 is a partial development view of the coil end, showing another modified example of the stator provided in the canned motor pump according to the present invention.

[0012] An embodiment of a canned motor pump according to the present invention will be described below. In the following description, reference will be made to the drawings as appropriate. In the drawings, the same members and elements are designated by the same reference numerals, and redundant description will be omitted. Furthermore, the dimensional proportions of the elements may be exaggerated for the sake of convenience, and are not limited to the proportions shown in the drawings.

[0013] In the following description, "downward" refers to the direction of gravity, and "upward" refers to the opposite direction of "downward."

[0014] Canned Motor Pump Configuration of the Canned Motor Pump First, the configuration of the canned motor pump will be described below.

[0015] 1 is a side view of a canned motor pump 1. For ease of explanation, the drawing shows a cross-sectional view of the upper half of the canned motor pump 1.

[0016] The canned motor pump 1 (hereinafter referred to as "the pump 1") is a leak-free pump with a pump section 2 and a motor section 3 integrated together. The pump 1 is used to pump high-temperature or highly hazardous liquids (e.g., explosive, flammable, or toxic liquids). The pump 1 comprises a pump section 2, a motor section 3, an adapter 4, a motor bearing wear monitor 5, a detection coil C (see Figure 3), lead wires L (see Figure 3), a protective sheet S (see Figure 3), and a string R (see Figure 3).

[0017] The configuration of the pump 1 is the same as that of a known canned motor pump, and therefore, in the following description, only an outline of the configuration of the pump 1 will be provided, and a detailed description will be omitted.

[0018] In the following description, "forward" refers to the direction in which the pump section 2 is positioned relative to the motor section 3, and "rearward" refers to the direction in which the motor section 3 is positioned relative to the pump section 2.

[0019] The pump unit 2 draws in and discharges the pumped liquid. The pump unit 2 includes a housing 20, an impeller 21, a pump chamber 22, a suction pipe 23, and a discharge pipe 24. The housing 20 defines the pump chamber 22 that houses the impeller 21, the suction pipe 23 that is a path for the pumped liquid drawn into the pump chamber 22, and the discharge pipe 24 that is a path for the pumped liquid discharged from the pump chamber 22. The impeller 21 draws in and discharges the pumped liquid using the rotational power of the motor unit 3. The pump chamber 22 is in communication with the suction pipe 23 and the discharge pipe 24.

[0020] The motor unit 3 is driven under predetermined driving conditions to rotate the impeller 21 of the pump unit 2. The motor unit 3 includes a housing 30, a rotating shaft 31, a bearing 32, a thrust washer 33, a rotor 34, a stator 35, a can 36, a sleeve 37, and a terminal 38.

[0021] FIG. 2 is a schematic cross-sectional view of the motor unit 3, showing a vertical cross section of the motor unit 3. As shown in FIG.

[0022] The housing 30 accommodates the stator 35 and the can 36 in a liquid-tight manner.

[0023] The rotating shaft 31 rotates together with the rotor 34. The rotating shaft 31 rotates due to the rotation of the rotor 34 and transmits rotational power to the impeller 21. The rotating shaft 31 is cylindrical in shape. The rotating shaft 31 is inserted through and fixed to the rotor 34. The front end of the rotating shaft 31 protrudes into the pump chamber 22, and the impeller 21 is attached to the front end. The rotating shaft 31 is provided with cylindrical shaft sleeves 311 that protect both sides of the rotating shaft 31.

[0024] In the following description, the "axial direction" is the direction along the rotation axis of the rotating shaft 31, the "radial direction" is the direction along the diameter (radius) of the rotating shaft 31 (stator 35), and the "circumferential direction" is the circumferential direction of the rotating shaft 31 (stator 35).

[0025] The bearings 32 support the rotating shaft 31 so that it can rotate freely. In the axial direction, the bearings 32 are arranged on both ends of the rotor 34. The bearings 32 are, for example, plain bearings. The thrust washer 33 limits the axial movement of the rotating shaft 31. The thrust washer 33 is attached to the rotating shaft 31 between the bearings 32 and the rotor 34.

[0026] The rotor 34 rotates due to a rotating magnetic field generated in the stator 35. The rotor 34 has a cylindrical shape.

[0027] Fig. 3 is a perspective view of the stator 35 included in the pump 1. Fig. 4 is an enlarged perspective view of the stator core 351, showing an enlarged tooth portion 35a on which the detection coil C is arranged. In the following description, Figs. 1 and 2 will be referred to as appropriate, along with Figs. 3 and 4.

[0028] The stator 35 generates a rotating magnetic field that rotates the rotor 34. The stator 35 has a substantially cylindrical shape. The stator 35 includes a stator core 351 and a plurality of conducting wires 352.

[0029] The stator core 351 holds a plurality of conducting wires 352. The stator core 351 is cylindrical in shape. The stator core 351 includes a plurality of teeth 35a. The teeth 35a are arranged on the inner circumferential surface of the stator core 351. The teeth 35a are members that protrude radially inward from the stator core 351 and extend along the axial direction. The teeth 35a are arranged at equal intervals in the circumferential direction. Slots 35b are formed between the teeth 35a, through which the conducting wires 352 are inserted.

[0030] Of the multiple tooth portions 35a, four tooth portions 35a have slit-shaped notches 35c cut out at both ends in the axial direction. That is, four notches 35c are formed in each of the openings at both ends of the stator core 351. In the circumferential direction, the four notches 35c are arranged at equal intervals (90° intervals) in each opening of the stator core 351. A detection coil C, which will be described later, is attached to the notches 35c.

[0031] The conductors 352 are inserted through the slots 35b and attached to the stator core 351. A portion of each of the plurality of conductors 352 protrudes from both ends of the stator core 351 in the axial direction. The protruding conductors 352 are bundled together to form annular coil ends 353.

[0032] The coil end 353 dissipates heat generated when the stator 35 generates a rotating magnetic field. The coil end 353 has an annular shape that follows the shape of the opening of the stator core 351. In the coil end 353, a plurality of conducting wires 352 are bent in the circumferential direction to form a bundle of conducting wires 352. The bundle of conducting wires 352 is gathered together with other bundles of conducting wires 352 to form the coil end 353. The coil end 353 has an inner circumferential surface 354. The shape of the inner circumferential surface 354 is approximately cylindrical.

[0033] In the following description, reference will be made primarily to FIG. 1 . The can 36 accommodates the rotating shaft 31, bearing 32, thrust washer 33, and rotor 34 in a liquid-tight manner. The can 36 is cylindrical. A portion of the pumped fluid introduced from the suction pipe 23 is introduced into the can 36 and used to cool the bearing 32 and motor unit 3. The pumped fluid used for cooling is discharged to the discharge pipe 24.

[0034] The sleeve 37 reinforces the can 36. The sleeve 37 covers the outer peripheral surface of the can 36 that is not covered by the stator core 351.

[0035] A plurality of conductors 352 held by the stator core 351 and lead wires L are connected to the terminal 38. The conductors 352 are connected to a power supply device (not shown) such as an inverter via the terminal 38.

[0036] The adapter 4 is connected to the rear end of the pump section 2 and the front end of the motor section 3, and connects the pump section 2 and the motor section 3 together.

[0037] The motor bearing wear monitoring device 5 monitors the wear state of the bearing 32 based on the detection signals output from each of the multiple detection coils C. In other words, the motor bearing wear monitoring device 5 monitors the wear state of the bearing 32 that supports the rotating shaft 31 by detecting a change in magnetic flux corresponding to a change in the position of the rotor 34 relative to the stator 35.

[0038] 5 is a schematic perspective view of the stator core 351, showing the arrangement of the detection coils C1 to C8. In the following description, FIGS. 1 to 4 will be referred to along with FIG.

[0039] The motor bearing wear monitoring device 5 is connected to eight detection coils C (C1, C2, C3, C4, C5, C6, C7, and C8) via lead wires L. The motor bearing wear monitoring device 5 includes a control unit (not shown), a memory unit (not shown), and a display unit (not shown).

[0040] The detection coils C (C1 to C8) detect magnetic flux changes corresponding to positional changes (displacement) of the rotor 34 relative to the stator 35. The detection coils C generate and output detection signals indicating the magnetic flux changes. The rotor 34 displaces axially together with the rotating shaft 31 in accordance with the amount of axial wear of the bearing 32, and displaces radially together with the rotating shaft 31 in accordance with the amount of radial wear of the bearing 32. In other words, the displacement of the rotor 34 can be considered to be the amount of wear of the bearing 32. Therefore, the motor bearing wear monitoring device 5 can detect the amount of wear of the bearing 32 by detecting the amount of displacement of the rotor 34 using the eight detection coils C (C1 to C8).

[0041] The detection coils C (C1 to C8) have a flat bobbin shape and include connection ends E to which lead wires L are connected. The detection coils C (C1 to C8) are fitted into the cutouts 35c of the stator 35.

[0042] In the circumferential direction, the detection coils C1 to C4 are attached at equal intervals (90° intervals) in the notches 35c located at the front ends of the tooth portions 35a. The detection coil C1 is positioned to face the detection coil C3 at a position 180° away, and the detection coil C2 is positioned to face the detection coil C4 at a position 180° away. Meanwhile, in the circumferential direction, the detection coils C5 to C8 are attached at equal intervals (90° intervals) in the notches 35c located at the rear ends of the tooth portions 35a. The detection coil C5 is positioned to face the detection coil C7 at a position 180° away, and the detection coil C6 is positioned to face the detection coil C8 at a position 180° away.

[0043] The amount of axial wear of the bearing 32 is detected by, for example, detection coils C2, C4, C6, and C8. The detection coils C2, C4, C6, and C8 detect magnetic flux changes corresponding to the axial displacement of the rotor 34 caused by an increase in the gap between the bearing 32 and the thrust washer 33. By detecting such magnetic flux changes, the amount of axial displacement of the rotor 34 (i.e., the amount of axial wear of the bearing 32) can be detected.

[0044] The radial wear of the bearing 32 is detected by, for example, the detection coils C1, C3, C5, and C7. The detection coils C1, C3, C5, and C7 detect magnetic flux changes corresponding to the radial displacement of the rotor 34 caused by an increase in the gap between the bearing 32 and the shaft sleeve 311. By detecting such magnetic flux changes, the radial displacement of the rotor 34 (i.e., the radial wear of the bearing 32) is detected.

[0045] The lead wire L transmits a detection signal detected by the detection coil C. The lead wire L is a known lead wire covered with an insulator. The lead wire L is connected to the connection end E of the detection coil C. In other words, two lead wires L are wired from the detection coil C. A portion of the lead wire L is wired so as to follow the inner circumferential surface 354 of the coil end 353. The lead wire L is connected to a terminal 38 which is connected to the motor bearing wear monitoring device 5.

[0046] The control unit controls the overall operation of the motor bearing wear monitoring device 5. The control unit is composed of, for example, a processor such as a CPU (Central Processing Unit), a volatile memory such as a RAM (Random Access Memory) that functions as a work area for the CPU, and a non-volatile memory such as a ROM (Read Only Memory) that stores various information such as programs and other control programs. The control unit is connected to, for example, a storage unit and a display unit.

[0047] Fig. 6 is an enlarged cross-sectional view of the coil end 353, enlarging part A in Fig. 2. In the following description, Figs. 2 and 3 will be referred to together with Fig. 6 as appropriate.

[0048] The protective sheet S protects the lead wires L. The protective sheet S is made of a material with high insulation properties and a low coefficient of thermal expansion. The coefficient of thermal expansion of the protective sheet S is smaller than that of the lead wires L. The protective sheet S is, for example, a known mica sheet or a known glass cloth sheet. The mica sheet is a sheet in which mica flakes are bound and solidified with resin. The glass cloth sheet is a sheet woven from glass fiber. The protective sheet S is shaped like a rectangle having short and long sides. The longitudinal length of the protective sheet S is equal to or greater than the length of the inner circumference of the inner circumferential surface 354 of the annular coil end 353. The lateral length of the protective sheet S is approximately the same as the length from the end of the stator core 351 to the open end of the annular coil end 353. The protective sheet S includes a first protective sheet S1 and a second protective sheet S2.

[0049] The first protective sheet S1 protects the lead wires L. The first protective sheet S1 is disposed between the inner circumferential surface 354 of the coil end 353 and the lead wires L. In the radial direction, the first protective sheet S1 has a first surface S1a facing the inner circumferential surface 354 and a second surface S1b facing the inner side of the coil end 353 in the radial direction. The first surface S1a of the first protective sheet S1 is disposed so as to be in contact with the inner circumferential surface 354. The lead wires L are wired so as to be in contact with the second surface S1b of the first protective sheet S1. In the circumferential direction, the first protective sheet S1 is disposed along the entire inner circumferential surface 354. In other words, the inner circumferential surface 354 is covered with a single first protective sheet S1. The first protective sheet S1 is an example of a protective sheet defined in the present invention.

[0050] In this way, the first protective sheet S1 is disposed between the inner circumferential surface 354 and the lead wire L. Therefore, in the portion where the first protective sheet S1 is disposed, the lead wire L does not come into contact with the inner circumferential surface 354. In the portion where the first protective sheet S1 is disposed, the tension caused by the expansion of the coil end 353 is applied to the first protective sheet S1. In other words, in the longitudinal direction of the lead wire L, the tension caused by the expansion of the coil end 353 is not directly applied to the lead wire L. Therefore, the lead wire L is not subjected to a tension strong enough to break the lead wire L. In other words, the tension in the longitudinal direction of the lead wire L is relaxed.

[0051] Furthermore, the first protective sheet S1 is disposed between the inner peripheral surface 354 and the lead wire L. Therefore, the lead wire L is not pinched between the conductor wires 352. Therefore, the lead wire L is not pressed from both sides of the lead wire L due to the expansion of the coil end 353.

[0052] That is, the first protective sheet S1 reduces the force applied to the lead wires L due to expansion / contraction caused by heating / cooling of the coil end 353, thereby preventing breakage of the lead wires L.

[0053] The second protective sheet S2 protects the lead wires L. In the radial direction, the second protective sheet S2 is disposed inside the first protective sheet S1 so as to face the first protective sheet S1. The second protective sheet S2, together with the first protective sheet S1, encloses the lead wires L. In the radial direction, the second protective sheet S2 has a first surface S2a facing the first protective sheet S1 and a second surface S2b facing the inner side of the coil end 353 in the radial direction. The first surface S2a of the second protective sheet S2 is disposed so as to contact the second surface S1b of the first protective sheet S1 and the lead wires L. In the circumferential direction, the second protective sheet S2 is disposed along the inner circumferential surface 354, covering the entire periphery of the inner circumferential surface 354. In other words, the second protective sheet S2 covers the entire periphery of the first protective sheet S1. The first protective sheet S1 and the lead wires L are covered by a single second protective sheet S2. The second protective sheet S2 is an example of the covering sheet of the present invention.

[0054] In this way, the lead wires L are covered with the second protective sheet S2, which prevents breakage of the lead wires L due to expansion / contraction caused by heating / cooling of the coil end 353. When assembling the pump 1, the second protective sheet S2 prevents breakage of the lead wires L due to accidental contact.

[0055] In the following description, reference will be made primarily to Figure 3. The string R binds the plurality of conductor wires 352 together, thereby maintaining the shape of the coil end 353 formed from the plurality of conductor wires 352. The coil end 353, which is made up of the plurality of conductor wires 352, is bound together with the first protective sheet S1, the second protective sheet S2, and the lead wire L by the string R. The string R is a known heat-resistant string.

[0056] The coil ends 353 bound with the strings R are impregnated with varnish (not shown) and hardened. That is, the first protective sheet S1, the second protective sheet S2, the lead wires L, and the strings R are hardened with the varnish together with the coil ends 353. The varnish is a known varnish.

[0057] Method of Arranging the Protective Sheet Next, a method of arranging the protective sheet S on the inner circumferential surface 354 of the coil end 353 will be described.

[0058] 7 is a partial development view of the coil end 353, showing the state in which the lead wire L is wired on the inner circumferential surface 354. The drawing schematically shows the stator core 351 and the coil end 353 in a state in which they are developed in the circumferential direction.

[0059] As described above, the coil end 353 is formed by bundling a plurality of conducting wires 352. A portion of each of the conducting wires 352 protrudes from the stator core 351 in the axial direction. The protruding conducting wires 352 are bent in the circumferential direction and bundled together. A bundle of conducting wires 352 is gathered together with other bundles of conducting wires 352. Thus, an annular coil end 353 is formed when viewed in the axial direction.

[0060] First, the detection coil C is placed on the tooth portion 35a of the stator core 351. At this time, the lead wire L is connected in advance to the connection end E by soldering or the like. The detection coil C is fitted into the notch 35c of 35a and fixed. At this time, the connection end E of the detection coil C is arranged axially from the end of the stator core 351 toward the outside of the end. The lead wire L extending from the connection end E is arranged along the inner circumferential surface 354 in a bent state so as not to apply unnecessary tension to the lead wire L.

[0061] Next, the first protective sheet S1 is placed.

[0062] Fig. 8 is a partial development view of the coil end 353, showing the state in which the first protective sheet S1 is arranged on the inner circumferential surface 354. The figure schematically shows the stator core 351 and the coil end 353 in a state in which they are developed in the circumferential direction. Fig. 9 is a schematic side view of the coil end 353, as viewed in the axial direction, showing the state in which the first protective sheet S1 is arranged on the inner circumferential surface 354 of Fig. 8.

[0063] In the circumferential direction, the first protective sheet S1 is disposed along the inner circumferential surface 354 so as to cover the entire circumference of the inner circumferential surface 354. The first protective sheet S1 is inserted between the inner circumferential surface 354 and the lead wires L so as to slide over the surface of the inner circumferential surface 354 from the open end of the coil end 353 toward the end of the stator core 351. At this time, the first protective sheet S1 is formed in a cylindrical shape that follows the inner circumferential surface 354.

[0064] Next, first protective sheet S1 is pressed against inner circumferential surface 354. Next, first protective sheet S1 is temporarily fixed to inner circumferential surface 354 with fixing tape (not shown). The fixing tape is a known tape that is heat resistant.

[0065] The lead wires L are wired in a bent state on the surface (second surface S1b) of the first protective sheet S1 and temporarily fixed to the surface (second surface S1b) of the first protective sheet S1 with fixing tape.

[0066] As shown in Fig. 9, four detection coils C are arranged in the opening of the stator core 351. Lead wires L extending from the four detection coils C are wired along the inner circumferential surface 354. Two lead wires L are wired from each of the four detection coils C. Eight lead wires L are wired on the inner surface (second surface S1b) of the first protective sheet S1 arranged on the inner circumferential surface 354. The eight lead wires L are bundled together and wired to the outside of the stator 35.

[0067] Next, the second protective sheet S2 is placed.

[0068] Fig. 10 is a partial development view of the coil end 353, showing the state in which the second protective sheet S2 is arranged on the inner circumferential surface 354. The figure schematically shows the stator core 351 and the coil end 353 developed in the circumferential direction. Fig. 11 is a schematic side view of the coil end 353, as viewed in the axial direction, showing the state in which the second protective sheet S2 is arranged on the inner circumferential surface 354 (first protective sheet S1) of Fig. 9.

[0069] In the radial direction, the second protective sheet S2 is disposed inward of the first protective sheet S1 so as to follow the first protective sheet S1. The second protective sheet S2 covers the first protective sheet S1 and the lead wires L and faces the first protective sheet S1. The second protective sheet S2 is disposed so as to cover the entire periphery of the inner circumferential surface 354. In this case, the second protective sheet S2 is formed in a cylindrical shape so as to follow the first protective sheet S1 and the inner circumferential surface 354.

[0070] Next, the second protective sheet S2 is pressed against the first protective sheet S1, and then the second protective sheet S2 is temporarily fixed to the inner peripheral surface 354 with fixing tape.

[0071] 11, eight lead wires L are wired between the first protective sheet S1 and the second protective sheet S2. That is, the eight lead wires L are enclosed within the first protective sheet S1 and the second protective sheet S2.

[0072] Next, the coil end 353 is tied with a string R.

[0073] FIG. 12 is a schematic side view of the coil end 353 as viewed in the axial direction, showing the coil end 353 tied with the string R.

[0074] The coil end 353 is bound together with the first protective sheet S1, the second protective sheet S2, and the lead wire L by the string R. That is, the first protective sheet S1, the second protective sheet S2, and the lead wire L, which are temporarily fixed to the inner circumferential surface 354 by the fixing tape, are bound together with the fixing tape by the string R and are bundled (fixed).

[0075] Next, the coil ends 353 bound with the strings R are immersed in varnish. That is, the first protective sheet S1, the second protective sheet S2, the lead wires L, and the strings R are immersed in the varnish together with the coil ends 353. Next, the varnish is dried, whereby the first protective sheet S1, the second protective sheet S2, the lead wires L, and the strings R, together with the coil ends 353, are hardened by the varnish.

[0076] Modifications Next, modifications of the pump 1 will be described below, focusing on the differences from the previously described embodiment (hereinafter referred to as the "first embodiment"). In the following description of the modifications, for ease of explanation, the same components as in the first embodiment and components having common functions are assigned the same reference numerals as in the first embodiment. In the following modifications, reference will be made as appropriate to Figures 1 to 12.

[0077] First Modification First, the first modification will be described.

[0078] FIG. 13 is an enlarged cross-sectional view of a coil end 353 showing a modified example of the stator 35.

[0079] 13 , the first modified example differs from the first embodiment in that the coil end 353 does not include the second protective sheet S2. The first protective sheet S1 is disposed between the inner circumferential surface 354 and the lead wires L. The lead wires L are routed on the surface (second surface S1b) of the first protective sheet S1. The lead wires L, together with the first protective sheet S1, are temporarily fixed to the inner circumferential surface 354 with fixing tape.

[0080] In this way, the first protective sheet S1 is disposed between the inner circumferential surface 354 and the lead wire L. Therefore, in the portion where the first protective sheet S1 is disposed, the lead wire L does not come into contact with the inner circumferential surface 354. In this portion where the first protective sheet S1 is disposed, tension due to the expansion of the coil end 353 is applied to the first protective sheet S1. As a result, tension in the longitudinal direction of the lead wire L is alleviated, similar to the first embodiment.

[0081] Furthermore, the first protective sheet S1 is disposed between the inner peripheral surface 354 and the lead wire L. Therefore, the lead wire L is not pinched between the conductor wires 352. Therefore, the lead wire L is not pressed from both sides of the lead wire L due to the expansion of the coil end 353.

[0082] That is, the first protective sheet S1 reduces the force applied to the lead wires L due to expansion / contraction caused by heating / cooling of the coil end 353, thereby preventing breakage of the lead wires L.

[0083] Second Modification Next, a second modification will be described.

[0084] 14 is a partial development view of a coil end 353 illustrating another modified example of the stator 35. The drawing schematically illustrates the stator core 351 and the coil end 353 in a state in which they are developed in the circumferential direction.

[0085] As shown in FIG. 14 , the second modified example differs from the first embodiment in that the first protective sheet S11 is disposed on a portion of the inner circumferential surface 354. The first protective sheet S11 is disposed between the inner circumferential surface 354 and the connection ends E of the plurality of detection coils C. The first protective sheet S11 has a rectangular sheet shape. In the circumferential direction, the first protective sheet S11 is slightly larger than the distance (width) between the pair of connection ends E. The first protective sheet S11 is disposed on the inner circumferential surface 354 in a specific region extending from the connection ends E along the axial direction of the rotation shaft 31.

[0086] The "specific region" is a region in the axial direction from the end on the stator core 351 side to the open end of the coil end 353, in which at least the connection end portions E of the detection coil C are arranged as viewed in the radial direction. In other words, the specific region has an area that is slightly larger than the maximum length between at least a pair of connection end portions E in the circumferential direction and is larger than at least the length of the connection end portions E in the axial direction.

[0087] The detection coil C and the lead wire L are connected by solder. Therefore, structurally, the strength of the connection between the connection end E and the lead wire L is weaker than the strength of other parts of the lead wire L. Therefore, due to expansion / contraction caused by heating / cooling of the coil end 353, the lead wire L may come off the detection coil C at this connection part before the lead wire L breaks. In other words, this connection part is more likely to break than other parts of the lead wire L. Therefore, the specific region includes at least the region where the connection end E is located.

[0088] The first protective sheet S11 is disposed at eight locations on the inner circumferential surface 354, corresponding to the eight detection coils C (C1 to C8). That is, the first protective sheet S11 is disposed at an end of the stator 35, between the connection end E of the corresponding detection coil C and the inner circumferential surface 354. At this time, the lead wires L are routed in a bent state on the surface of the first protective sheet S11. The lead wires L, together with the first protective sheet S11, are temporarily fixed to the inner circumferential surface 354 with fixing tape.

[0089] The first protective sheet S11 is disposed at least between the connection end E and the inner circumferential surface 354. Therefore, the connection end E (the connection portion between the connection end E and the lead wire L) does not contact the inner circumferential surface 354. In other words, tension due to the expansion of the coil end 353 is not applied to the connection portion. This prevents the lead wire L from coming off the connection end E due to expansion / contraction caused by heating / cooling of the coil end 353.

[0090] Summary According to the embodiment described above, the pump 1 includes the motor bearing wear monitoring device 5, the rotating shaft 31, the bearing 32, the rotor 34, the stator 35, the can 36, multiple detection coils C, lead wires L, and a protective sheet S (first protective sheet S1). The lead wires L are connected to the detection coil C and the motor bearing wear monitoring device 5. The protective sheet S protects the lead wires L. The stator 35 includes a stator core 351 and multiple conductors 352. The conductors 352 are attached to the stator core 351. A portion of each of the multiple conductors 352 protrudes from the stator core 351 in the axial direction to form annular coil ends 353. A portion of the lead wires L is routed along the inner circumferential surface 354 of the coil end 353. The first protective sheet S1 is disposed between the inner circumferential surface 354 and the lead wires L. With this configuration, the lead wire L does not come into contact with the inner circumferential surface 354 in the portion where the first protective sheet S1 is disposed. That is, the tension caused by the expansion of the coil end 353 is not directly applied to the lead wire L. Therefore, the lead wire L is not subjected to a tension strong enough to break the lead wire L. In other words, the tension applied to the lead wire L along the longitudinal direction of the lead wire L is relaxed. Therefore, breakage of the lead wire L due to expansion and contraction of the coil end 353 is prevented.

[0091] Furthermore, according to the embodiment described above, each of the multiple detection coils C has a connection end E to which the lead wire L is connected. The first protective sheet S1 is disposed between the inner circumferential surface 354 and the connection end E of each of the multiple detection coils C. With this configuration, the first protective sheet S1 is disposed between at least the connection end E (connection portion) and the inner circumferential surface 354, so the connection end E (connection portion) does not contact the inner circumferential surface 354 of the coil end 353. In other words, tension due to expansion of the coil end 353 is not directly applied to the connection end E (connection portion). This prevents the lead wire L from becoming detached from the connection end E due to expansion and contraction of the coil end 353.

[0092] Furthermore, according to the embodiment described above, the first protective sheet S1 is disposed in a specific region extending from the connection end E along the axial direction of the rotating shaft 31. With this configuration, the lead wire L does not come into contact with the inner circumferential surface 354 of the coil end 353 in the specific region extending from the connection end E along the axial direction of the rotating shaft 31. In other words, tension due to expansion of the coil end 353 is not directly applied to the lead wire L in the specific region extending from the connection end E along the axial direction of the rotating shaft 31. Therefore, breakage of the lead wire L in the specific region due to expansion and contraction of the coil end 353 is further prevented.

[0093] Furthermore, according to the embodiment described above, the first protective sheet S1 is disposed circumferentially along the inner circumferential surface 354. With this configuration, the lead wires L do not come into contact with the inner circumferential surface 354 of the coil end 353. That is, the lead wires L are less likely to be pulled in the circumferential direction of the coil end 353. Therefore, breakage of the lead wires L due to expansion and contraction of the coil end 353 is further prevented.

[0094] Furthermore, according to the embodiment described above, in the pump 1, the first protective sheet S1 is disposed around the entire inner circumferential surface 354. With this configuration, the lead wires L of the pump 1 do not come into contact with the inner circumferential surface 354 of the coil end 353 along the entire inner circumferential surface 354. In other words, the lead wires L are less likely to be pulled in the circumferential and radial directions of the coil end 353. Therefore, regardless of where the lead wires L are routed on the inner circumferential surface 354, breakage of the lead wires L due to expansion and contraction of the coil end 353 is further prevented.

[0095] Furthermore, according to the embodiment described above, the pump 1 includes a second protective sheet S2 disposed opposite the first protective sheet S1. The second protective sheet S2 covers the first protective sheet S1 so as to enclose the lead wires L between the first protective sheet S1 and the second protective sheet S2. With this configuration, the lead wires L are covered and protected (enclosed) by the second protective sheet S2, preventing malfunctions (such as breakage) of the lead wires L due to accidental contact during assembly of the pump 1.

[0096] Furthermore, according to the embodiment described above, the thermal expansion coefficient of the first protective sheet S1 of the pump 1 is smaller than that of the lead wires L. With this configuration, the lead wires L are routed to the inner circumferential surfaces 354 of the coil ends 353 via the first protective sheet S1, which has a smaller thermal expansion coefficient than the lead wires L. In other words, the tension applied to the lead wires L due to the expansion of the coil ends 353 is alleviated by the first protective sheet S1. Therefore, breakage of the lead wires L due to the expansion and contraction of the coil ends 353 is prevented.

[0097] Furthermore, according to the embodiment described above, the material of the first protective sheet S1 of the pump 1 is an insulating material. With this configuration, the insulation between the coil end 353 and the lead wire L is improved.

[0098] Other Embodiments In the first embodiment described above, the protective sheets S (first protective sheet S1 and second protective sheet S2) covering the inner circumferential surface 354 are not limited to insulating mica sheets or glass cloth sheets. That is, for example, the material of the protective sheets S may be paper or resin. Furthermore, the protective sheets S do not have to be insulating.

[0099] In the first embodiment described above, the first protective sheet S1 and the second protective sheet S2 that cover the entire periphery of the inner circumferential surface 354 are not limited to a single sheet each. That is, for example, the first protective sheet S1 and the second protective sheet S2 may be multiple sheets that cover the entire periphery of the inner circumferential surface 354.

[0100] Furthermore, in the first embodiment described above, the first protective sheet S1 and the second protective sheet S2 covering the inner circumferential surface 354 are not limited to being rectangular sheets. That is, the shape of each of the first protective sheet S1 and the second protective sheet S2 may be any shape other than rectangular as long as they can be positioned between the inner circumferential surface 354 and the lead wires L.

[0101] Furthermore, in the first embodiment described above, the first protective sheet S1 and the second protective sheet S2 may have a plurality of through holes, so that some of the heat generated from the coil end 353 can be released through the through holes.

[0102] Furthermore, in the first embodiment described above, the number of detection coils C1 to C8 is not limited to 8. In this case, for example, in the second modified example described above, the number of first protective sheets S11 corresponds to the number of detection coils C.

[0103] Furthermore, in the second modified example described above, a second protective sheet having the same shape as the first protective sheet S11 may be disposed so as to face the first protective sheet S11 and the connection end E.

[0104] Embodiments of the Present Invention Next, embodiments of the present invention that can be understood from the above-described embodiments will be described below, using the terms and symbols described in the respective embodiments.

[0105] A first embodiment of the present invention includes a rotor (e.g., rotor 34), a stator (e.g., stator 35) that rotates the rotor, a rotating shaft (e.g., rotating shaft 31) that rotates together with the rotor, a bearing (e.g., bearing 32) that supports the rotating shaft, a cylindrical can (e.g., can 36) that accommodates the rotor, the rotating shaft, and the bearing, a plurality of detection coils (e.g., detection coil C) that detect magnetic flux changes corresponding to positional changes of the rotor relative to the stator, a motor bearing wear monitoring device (e.g., motor bearing wear monitoring device 5) that monitors the wear state of the bearing based on detection signals output from each of the plurality of detection coils, and a motor bearing wear monitoring device connected to the detection coils. A canned motor pump (e.g., the pump 1) includes lead wires (e.g., lead wire L) attached to the stator core and a protective sheet (e.g., first protective sheet S1) that protects the lead wires. The stator includes a stator core (e.g., stator core 351) and a plurality of conductors (e.g., conductor wire 352) attached to the stator core. A portion of each of the conductors protrudes from the stator core in the axial direction of the rotating shaft to form annular coil ends (e.g., coil end 353). A portion of the lead wires is routed along an inner circumferential surface (e.g., inner circumferential surface 354) of the coil end. The protective sheet is disposed between the inner circumferential surface and the lead wires. With this configuration, the lead wires do not come into contact with the inner circumferential surface of the coil end where the protective sheet is disposed. This prevents breakage of the lead wires due to expansion and contraction of the coil end.

[0106] A second aspect of the present invention is the canned motor pump of the first aspect, wherein each of the plurality of detection coils has a connection end (e.g., connection end E) to be connected to the lead wire, and the protective sheet is disposed between the inner circumferential surface and the connection end of each of the plurality of detection coils. With this configuration, the lead wire is prevented from coming off the connection end of the detection coil due to expansion and contraction of the coil end.

[0107] A third aspect of the present invention is a canned motor pump according to the second aspect, wherein the protective sheet is disposed in a specific region along the axial direction of the rotating shaft from the connection end. This configuration further prevents breakage of the lead wire in the specific region due to expansion and contraction of the coil end.

[0108] A fourth aspect of the present invention is a canned motor pump according to the third aspect, wherein the protective sheet is disposed along the inner peripheral surface in the circumferential direction of the rotating shaft. With this configuration, the lead wires do not come into contact with the inner peripheral surface of the coil end. That is, the lead wires are less likely to be pulled in the circumferential direction of the coil end. This prevents breakage of the lead wires due to expansion and contraction of the coil end.

[0109] A fifth aspect of the present invention is a canned motor pump according to the fourth aspect, in which the protective sheet is disposed around the entire inner circumferential surface. With this configuration, the lead wires do not come into contact with the inner circumferential surface of the coil end. That is, the lead wires are less likely to be pulled in the circumferential and radial directions of the coil end. Therefore, regardless of where the lead wires are routed on the inner circumferential surface, breakage of the lead wires due to expansion and contraction of the coil end is prevented.

[0110] A sixth aspect of the present invention is a canned motor pump according to any one of the first to fifth aspects, further comprising a covering sheet (e.g., a second protective sheet S2) disposed opposite the protective sheet, the covering sheet covering the protective sheet so as to enclose the lead wires between the protective sheet and the covering sheet. With this configuration, the lead wires are covered and protected (enclosed) by the covering sheet, thereby preventing malfunction of the lead wires (e.g., breakage) due to accidental contact during assembly of the canned motor pump.

[0111] A seventh aspect of the present invention is a canned motor pump according to the first aspect, wherein the thermal expansion coefficient of the protective sheet is smaller than that of the lead wires. According to this configuration, the lead wires are routed on the inner circumferential surface of the coil end via a protective sheet having a thermal expansion coefficient smaller than that of the lead wires. In other words, the tension on the lead wires due to the expansion of the coil end is alleviated by the protective sheet. Therefore, breakage of the lead wires due to the expansion and contraction of the coil end is prevented.

[0112] An eighth aspect of the present invention is the canned motor pump of the first aspect, wherein the protective sheet is made of an insulating material. With this configuration, the insulation between the coil end and the lead wire is improved.

[0113] A ninth aspect of the present invention is the canned motor pump of the first aspect, wherein the protective sheet has a plurality of through holes. According to this configuration, the plurality of through holes allow heat generated from the coil ends to be released. Therefore, the protective sheet can efficiently release the heat generated from the coil ends to the outside.

[0114] REFERENCE SIGNS LIST 1 canned motor pump 2 pump section 3 motor section 31 rotating shaft 32 bearing 34 rotor 35 stator 351 stator core 352 conducting wire 353 coil end 354 inner peripheral surface 36 can 5 motor bearing wear monitoring device C1 to C8 detection coils E connection end L lead wire S protective sheet S1 first protective sheet S2 second protective sheet

Claims

1. A canned motor pump comprising: a rotor; a stator that rotates the rotor; a rotating shaft that rotates together with the rotor; a bearing that supports the rotating shaft; a cylindrical can that houses the rotor, the rotating shaft, and the bearing; a plurality of detection coils that detect magnetic flux changes corresponding to changes in the position of the rotor relative to the stator; a motor bearing wear monitoring device that monitors the wear state of the bearing based on detection signals output from each of the plurality of detection coils; lead wires that connect the detection coils and the motor bearing wear monitoring device; and a protective sheet that protects the lead wires, wherein the stator comprises a stator core and a plurality of conducting wires attached to the stator core, wherein a portion of each of the plurality of conducting wires protrudes from the stator core in the axial direction of the rotating shaft to form annular coil ends, and a portion of the lead wires is routed along the inner surface of the coil end, and the protective sheet is arranged between the inner surface and the lead wires.

2. A canned motor pump as described in claim 1, wherein each of the plurality of detection coils has a connection end connected to the lead wire, and the protective sheet is disposed between the inner circumferential surface and the connection end of each of the plurality of detection coils.

3. The canned motor pump according to claim 2, wherein the protective sheet is disposed in a specific region extending from the connection end along the axial direction of the rotating shaft.

4. The canned motor pump according to claim 3, wherein the protective sheet is disposed along the inner circumferential surface in the circumferential direction of the rotating shaft.

5. A canned motor pump according to claim 4, wherein the protective sheet is disposed around the entire inner circumferential surface.

6. A canned motor pump according to any one of claims 1 to 5, further comprising: a covering sheet disposed opposite said protective sheet, said covering sheet covering said protective sheet so as to enclose said lead wires between said protective sheet and said covering sheet.

7. The canned motor pump according to claim 1, wherein the thermal expansion coefficient of the protective sheet is smaller than that of the lead wires.

8. The canned motor pump according to claim 1, wherein the protective sheet is made of an insulating material.

9. The canned motor pump according to claim 1, wherein the protective sheet has a plurality of through holes.

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