JP4739857B2 - Resin can for canned motor and manufacturing method thereof, injection mold, canned motor, canned motor pump - Google Patents

Description

  The present invention is a canned motor having a structure in which a can that separates and blocks the stator side space from the rotor side space in an airtight and liquid tight manner in the gap between the stator and the rotor, a resin can used therefor, and a manufacturing method thereof, The present invention relates to an injection mold and a canned motor pump using the canned motor.

  A canned motor may be used as a motor that drives a vacuum pump, a chemical pump that handles liquid chemicals, and the like. FIG. 12 is a longitudinal sectional view showing an example of this type of canned motor. A stator 100 in which a coil 102 is wound around a stator core 101 is fitted into and fixed to an inner peripheral portion of a bottomed cylindrical motor frame 103, and this is also a bottomed cylindrical shape inside the stator 100. The can 105 is fixed. The rotor 110 is rotatably supported by a bearing (not shown) or the like inside the can 105 (see Patent Document 1).

  In this conventional canned motor, a can made of stainless steel or a resin can molded with a thick wall using a general thermoplastic resin has been used as the can 105 (see Patent Documents 1 and 2). ). However, in the case of the stainless steel can, there is a problem that the rotating magnetic field by the rotor 110 acts on the surface thereof to generate an eddy current and the motor efficiency is lowered due to the loss caused by the eddy current.

In addition, since the conventional resin can is thick, it is necessary to increase the air gap between the stator 100 and the rotor 110. For this reason, in order to obtain the same output as that of a normal motor without a can, it is necessary to increase the motor current or increase the number of turns of the coil 102, thereby increasing the loss and lowering the motor efficiency.
JP 2005-184958 A Japanese Patent Application Laid-Open No. 07-59289

  The present invention has been made to solve such problems of the prior art, and its problem is to provide a thin and tough resin can for a can motor, in addition to the resin can. The present invention provides a canned motor and a canned motor pump.

The invention according to claim 1 for solving the above-mentioned problem is disposed in an air gap (57) between a stator (3) and a rotor (4) having a rotating shaft (39) in a canned motor. A canned molded with a liquid crystal polymer resin having a bottomed cylindrical shape that separates and blocks the stator side space (35) and the rotor side space (36) in an airtight and liquid-tight manner and has a fixing flange (28) at the periphery of the open end. A resin can for a motor (5), characterized in that a convex portion (56) having a cold slug formed from the liquid crystal polymer resin is provided to protrude from the center of the bottom surface toward the rotating shaft inside the can. And

If so thus provided a convex portion having a co Rudosuragu injection start early in the molten resin of cold slag produced by contacting the mold cavity is trapped in the part forming the convex portion Entering the flow path is prevented. As a result, the fluidity and filling property of the resin in the cavity are uniform, and a weld line is not generated, and the strength of the can is increased.
If a liquid crystal polymer resin is used, a tough thin resin can with high dimensional accuracy can be formed. As a result, the air gap can be narrowed and the performance of the canned motor can be improved.

The invention according to claim 2 is the resin can for canned motor according to claim 1, wherein the can is mounted on the canned motor at an outer peripheral portion of the cylindrical portion and extending in the axial direction. In this state, an elongated reinforcing rib (59) that fits into the opening (17) of the coil winding slot (16) provided in the stator core (13) of the stator is projected. And
If such a reinforcing rib is provided, the strength of the can barrel portion can be increased.

The invention described in claim 3 is an injection mold for molding the resin can for the can motor according to claim 1 or 2 by injection molding, and an upper mold for molding the outer surface of the can ( 44) and a lower mold (45) for molding the inner surface, and the upper mold has a sprue (48) for injecting molten resin into the cavity (53) at the center of the portion for molding the cylindrical bottom surface. A concave portion (52) which has an opening (49) and functions as a cold slug reservoir is provided in the lower mold portion facing the opening.

  If the lower mold is provided with such a recess functioning as a cold slag reservoir, the cold slag generated by the molten resin coming into contact with the mold at the beginning of injection is captured by the recess and the flow path in the cavity. It is blocked from entering. As a result, the fluidity and filling property of the resin in the cavity are uniform, and no weld line is generated, and it is possible to mold a high strength can.

According to a fourth aspect of the present invention, there is provided a method for producing a resin can for a can motor, wherein the upper mold and the lower mold in the injection mold according to the third aspect are closed, and the sprue It is characterized by injecting a molten resin through.

  According to such a manufacturing method, the cold slag generated when the molten resin comes into contact with the mold at the beginning of injection is prevented from being captured by the concave portion and entering the flow path in the cavity. As a result, the fluidity and filling property of the resin in the cavity are uniform, and no weld line is generated, and it is possible to mold a high strength can.

According to a fifth aspect of the present invention, the stator (3) formed by winding the coil (20) around the stator core (13) is fitted into the inner peripheral portion of the bottomed cylindrical motor frame (2). fixed, a canned motor which is disposed rotatably a rotor (4) therein disposed the can (5) bottomed cylindrical inside of the stator, according to claim 1 or 2 The canned motor resin can is fixed to the motor frame so as to separate and block the stator side space (35) and the rotor side space (36), and the rotor attaches the rotating shaft (39) to the canned motor. The driven device (10) is directly connected to the input rotation shaft (41) and is configured to rotate while being supported by the input rotation shaft.

  In the canned motor having such a configuration, components arranged in the stator side space are not affected by the atmosphere in the rotor side space. On the other hand, there is an effect that the influence of the atmosphere in the stator side space on the components arranged in the rotor side space or the liquid, gas, etc. existing in the space can be eliminated.

The invention according to claim 6 is a canned motor pump, and the driven device (10) driven by the canned motor according to claim 5 is used as a pump so that the pump and the canned motor are integrated. It is characterized by having comprised it.

  According to the canned motor pump having such a configuration, it is possible to prevent the components arranged in the stator side space from being affected by the liquid, gas, or the like conveyed by the pump. On the contrary, there is an effect that it is possible to prevent the atmosphere in the stator side space from affecting the liquid, gas, etc. conveyed by the pump.

  Hereinafter, an embodiment of a canned motor according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing the configuration of the canned motor. The canned motor 1 includes a motor frame 2, a stator 3, a rotor 4, and a resin can 5 disposed therebetween.

  The motor frame 2 is manufactured by casting or press-molding a steel plate. The motor frame 2 has a bottomed cylindrical shape, and a flange 6 protruding outward in the radial direction is formed on the periphery of the opening. The motor frame 2 is used by being fixed to the housing 11 of the driven device 10 with bolts, screws or the like.

  A stator 3 formed in a cylindrical shape is press-fitted and fixed inside the motor frame 2. The stator 3 is obtained by winding a winding around a stator core 13 formed by laminating a large number of silicon steel plates punched in an annular shape. As shown in FIG. 2, a plurality of magnetic pole teeth 15 projecting radially inward from the annular yoke portion 14 corresponding to the outer peripheral portion of the stator core 13 are formed at equal intervals. Slots 16 are formed between adjacent magnetic pole teeth 15. A gap between the tips of adjacent magnetic pole teeth 15 is an opening 17 of the slot 16. A winding is wound around each magnetic pole tooth 15 via an insulator 18 to form an armature winding (armature coil) 20. As shown in FIG. 1, a power cord 23 is connected to the armature winding 20 through a hole 22 provided in the motor frame 2, and a power supply connector 24 is connected to the tip of the power cord 23. .

  A bottomed cylindrical can 5 is inserted on the inner peripheral surface of the stator 3 so that the outer peripheral surface thereof is in contact with the inner peripheral surface of the stator 3. The can 5 is formed of a resin. As shown in FIG. 3, the body 26 has a thin cylindrical shape, and one end in the axial direction is closed to form a bottom 27. The other end in the axial direction is an opening, and a flange 28 protruding outward in the radial direction is formed at the periphery.

  The flange 28 of the can 5 is formed so that its outer peripheral portion is within the diameter of the flange 6 of the motor frame 2. A notch groove 30 for fitting the outer peripheral portion of the flange 28 of the can 5 is provided in the inner peripheral edge portion of the flange 6 of the motor frame 2. Further, a plurality of through holes 31 are formed in the outer peripheral portion of the flange 28 of the can 5, and a screw hole 32 is provided in the notch groove 30 of the flange 6 of the motor frame 2 facing the through hole 31. . The can 5 is screwed onto the motor frame 2 by inserting a screw 33 through the through hole 31 after applying an adhesive to the contact surface of the flange 28 and the notch groove 30 and fitting the can. With such a configuration, the stator side space 35 in which the stator 3 is disposed and the rotor side space 36 inside the can 5 are separated and cut off in an airtight and liquid tight manner.

  The rotor 4 is disposed inside the can 5. The rotor 4 is a magnet-embedded rotor in which permanent magnets are embedded in a rotor core 38 formed by laminating a large number of silicon steel plates punched in an annular shape, and a rotating shaft 39 is inserted and fixed at the center.

  The canned motor 1 of the present embodiment is a motor that is configured integrally with, for example, a pump that is the driven device 10 and that mainly rotates the input rotating shaft 41. Therefore, the rotating shaft 39 of the motor 1 is directly connected to the input rotating shaft 41 of the driven device 10 and is integrally formed. The motor 1 does not have a bearing mechanism for supporting its own rotating shaft 39. Since the input rotating shaft 41 of the driven device 10 is supported by the bearing mechanism 42 for the driven device 10, the rotating shaft 39 of the motor 1 formed integrally with the input rotating shaft 41 is also supported, thereby the rotor. 4 is configured to be able to rotate within the can 5.

  Under such a configuration, when a multiphase alternating current is supplied to the armature winding 20 via the power cord 23, a rotating magnetic field is generated around the rotor 4 to generate a rotating torque, and the rotating shaft 39 rotates. Driven. As a result, the input rotary shaft 41 of the driven device 10 formed integrally with the rotary shaft 39 also receives the rotational driving force and rotates.

  Next, a method for forming the can 5 used in the canned motor 1 will be described. The can 5 is formed by injection molding a resin. For the molding, two injection molds such as an upper mold 44 and a lower mold 45 as shown in FIG. The upper mold 44 is a mold for forming the outer shape of the bottomed cylindrical can 5 having the flange 28, and a columnar cavity 46 is bored upward from the lower surface of the mold, and the peripheral edge of the lower end that is an opening An annular notch 47 for forming the outer surface of the flange 28 is formed in the part. An opening (resin injection port) 49 of a sprue 48 serving as a molten resin inflow path is formed at the center of the ceiling of the cavity 46.

  The lower mold 45 is a mold that molds the inner surface of the can 5 and has a shape in which a cylindrical portion 50 is erected on a flat surface. The feature of the lower mold 45 of the present embodiment is that a concave portion 52 that functions as a cold slug reservoir is provided in the central portion of the top of the cylindrical portion 50 that forms the inner bottom surface of the can 5. FIG. 4 (2) shows a state in which the upper mold 44 and the lower mold 45 are closed, and the recess 52 of the lower mold 45 faces the opening 49 of the sprue 48 of the upper mold 44. In position. A cavity 53 that is a space for molding the can 5 is formed between the upper mold 44 and the lower mold 45.

  At the time of injection molding, the molten resin injected from the nozzle of the injection molding machine enters through the sprue 54 as shown in FIG. 5 (1), flows through the sprue 48, and flows into the cavity 53 through the opening 49. In this case, the molten resin injected into the sprue 48 at the beginning of the injection starts and the leading portion thereof contacts the inner wall of the sprue 48 and is cooled. The cooled molten resin is cured and converted into slag to form cold slag.

  When the lower mold 45a as shown in FIG. 5 (2) in which the concave portion 52 is not provided at the position facing the opening 49 of the sprue 48 is used, the hardened cold slug 55 is as shown in the figure. It enters the flow path in the cavity 53 and inhibits the uniform flow of the resin. As a result, a weld line having a weak cracking strength may be generated and a portion having insufficient strength may be formed.

  On the other hand, in the case of this embodiment in which the concave portion 52 is provided in the portion of the lower mold 45 facing the opening 49 of the sprue 48 as shown in FIG. It is captured by the recess 52 and is prevented from entering the flow path in the cavity 53. That is, the recess 52 functions as a cold slag reservoir that captures the cold slag. As a result, the fluidity and filling property of the resin in the cavity 53 are uniform, and a weld line is not generated, and a can having a high strength can be molded. Note that the cold slag captured and solidified by the concave portion 52 forms a convex portion 56 at the center of the bottom surface of the can 5 (see FIG. 1).

  By the way, the body portion 26 of the can 5 is disposed in an air gap 57 (see FIG. 1) between the inner peripheral surface of the stator 3 and the outer peripheral surface of the rotor 4. The air gap 57 exists in the magnetic path of the magnetic flux and becomes a magnetic resistance. Therefore, the narrower the better. In order to reduce the width of the air gap 57, the body portion 26 of the can 5 may be formed thin. However, if the thickness is reduced, the strength is lowered.

  In a conventional resin can molded from a general thermoplastic resin, the thickness of the air gap 57 must be narrowed to ensure strength from the flowability of the resin and the problem of insufficient strength after molding. It was difficult to do. In order to solve this problem, the can motor 1 of the present embodiment employs a can 5 molded using a liquid crystal polymer resin. The liquid crystal polymer resin has a high fluidity in a molten state, has a small molding shrinkage during solidification, and exhibits high strength after solidification. Accordingly, if a liquid crystal polymer resin is used, a tough and thin resin can with high dimensional accuracy can be formed. As a result, the air gap 57 can be narrowed, and the performance of the canned motor 1 can be improved.

  FIG. 6 is a perspective view showing an outer shape of another embodiment having an effect of further increasing the strength of the body portion of the can 5. The can 5a is formed by projecting a plurality of elongated reinforcing ribs 59 extending in the axial direction to the flange 28 on the outer peripheral portion of the body portion 26. As shown in FIG. 7, the reinforcing rib 59 is attached so that the convex portion of the reinforcing rib 59 fits into the opening 17 of the coil winding slot 16 when the can 5 a is inserted inside the stator 3. The position and cross-sectional shape are determined.

  Such reinforcing ribs 59 increase the strength of the body portion 26. Further, if the upper mold 44 is formed so that such reinforcing ribs 59 are formed, the cavity portion where the reinforcing ribs 59 are formed at the time of molding also serves as a flow path for the molten resin. For this reason, the flow of the molten resin to the body portion 26 and the flange 28 portion is improved, and an effect of preventing the generation of a weld line having a weak cracking strength is obtained.

  Next, an embodiment of a canned motor pump equipped with a pump as the driven device 10 in FIG. 1 will be described with reference to FIG. A pump 61 incorporated in the canned motor pump 60 shown in the figure is an inscribed gear pump, and FIG. 9 shows a cross-sectional view along the line AA ′ in the figure. The pump 61 includes a casing 63, an end plate 64, an inner rotor 65, an outer rotor 66, and a shaft (input rotation shaft) 41.

  The inner rotor 65 is a circumscribed gear having n (four in the figure) external teeth, and is fitted to the outer peripheral portion of the shaft 41. The outer rotor 66 is an annular internal gear having (n + 1) internal teeth that mesh with external teeth of the inner rotor 65. The casing 63 is formed with a bottomed cylindrical cavity 68 for rotatably housing the outer rotor 66, and the opening is closed by an end plate 64.

  The end plate 64 is provided with a suction port 69 and a discharge port 70 for sucking and discharging the liquid to be pumped, and these lead to a space formed between the outer teeth of the inner rotor 65 and the inner teeth of the outer rotor 66. ing. The shaft 41 is rotatably supported by a through hole 71 provided in the casing 63 and a bottomed hole 72 provided in the end plate 64.

  The rotation centers of the inner rotor 65 and the outer rotor 66 are decentered by a certain distance. When the shaft 41 is rotationally driven and the inner rotor 65 rotates, the outer rotor 66 is also rotated by the meshing of the outer teeth with the inner teeth of the outer rotor 66. Among the plurality of spaces formed between the inner teeth and the outer teeth, the space connected to the suction port 69 increases in volume and decreases in pressure due to the rotation, and sucks liquid through the suction port 69. On the contrary, the space connected to the discharge port 70 is reduced in volume and pressure is increased, and the liquid in the space is pushed out to the discharge port 70. By repeating such an operation accompanying the rotation of the shaft 41, the pump action of sucking and pressurizing the liquid from the suction port 69 and discharging it from the discharge port 70 is continuously performed.

  The canned motor pump 60 of the present embodiment is driven by the canned motor 1, and the canned motor 1 has the stator-side space 35 and the rotor-side space 36 separated and cut off by the can 5 in an airtight and liquidtight manner as described above. Yes. Therefore, even if corrosive or conductive liquid oozes out from the pump 61 to the motor 1 side, the stator 3 does not come into contact with them, so that the effect of not suffering damage such as corrosion and electrical insulation deterioration is obtained. On the contrary, the atmosphere of the stator side space 35 does not affect the liquid, gas, etc. to be pumped.

  In the above description, the internal gear pump is described as an example of the pump 61. However, a positive displacement pump such as an external gear pump, a roots pump, a screw pump, or a claw pump is employed as the driven device 10. However, the same effect can be obtained. The same effect can be obtained not only by the liquid pump but also by a pressure pump or a vacuum pump that pumps air.

(Modified embodiment)
In the embodiment, the can 5 shown in FIG. 3 and the can 5a with the reinforcing rib 59 shown in FIG. 6 are each formed by integrally forming a donut-shaped disc-shaped flange 28 on the periphery of the opening. However, the flange portion may have a shape as shown in the can longitudinal sectional view of FIG. The flange 28a of the can 5b is formed in a cylindrical shape having a tapered surface in which the outer peripheral surface of the donut disk-shaped flange is gradually enlarged toward the opening side of the can 5b.

  FIG. 11 is a longitudinal sectional view in which the canned motor 1a employing the can 5b shown in FIG. In the case of the canned motor 1 a, the can 5 b is supported by fixing the flange 28 a portion to the housing 11 of the driven device 10. A cylindrical insertion hole 80 through which the body portion 26 of the can 5 b is inserted is opened in the housing 11 of the driven device 10 with its axis aligned with the axis of the shaft 41. The inner peripheral surface of the insertion hole 80 is formed in a cylindrical shape that forms a tapered surface that gradually increases in diameter toward the inner side of the driven device 10, and the taper angle is that of the outer peripheral surface of the flange 28 a of the can 5 b. The taper angle is matched.

  The can 5 b is attached such that the flange 28 a is sandwiched between the inner peripheral surface of the insertion hole 80 provided in the housing 11 and the cylindrical outer peripheral surface of the bearing mechanism 41. A donut disk-like back plate 81 is fixed around the insertion hole 80 on the inner surface side of the housing 11 with its center aligned with the axis of the shaft 41. A plurality of through screw holes 83 are screwed into the back plate 81 portion of the can 5b facing the axial end surface 82 of the flange 28a, and the through screw hole 83 is formed on the axial end surface 82 of the flange 28a. A screw 84 is screwed in the direction.

  When the screw 84 is screwed in, the tip end portion of the screw 84 comes into contact with the axial end surface 82 of the flange 28 a and pushes the flange 28 a into the insertion hole 80 of the housing 11. By this pressing, the outer peripheral tapered surface of the flange 28 a is pressed against the inner peripheral tapered surface of the insertion hole 80, and the inner peripheral surface of the flange 28 a is pressed against the cylindrical outer peripheral surface of the bearing mechanism 41. By such pressing, the outer peripheral surface and the inner peripheral surface of the flange 28 a are constrained, so that the can 5 b is held in a state where the central axis is aligned with the axis of the shaft 41.

  In this positioned state, the outer peripheral taper surface of the flange 28a is in close contact with the inner peripheral taper surface of the insertion hole 80 to block the passage of liquid and gas. For this reason, the stator side space 35 and the rotor side space 36 are separated and cut off in an airtight and liquid tight manner. At the same time, the stator-side space 35 and the space inside the driven device 10 are separated and cut off in an airtight and liquidtight manner. Therefore, the atmosphere in the rotor side space 36 does not affect the rotor side space 36 and the space in the driven device 10. Conversely, the atmosphere in the rotor side space 36 and the space in the driven device 10 is the stator side. The space 35 is not affected.

1 is a longitudinal sectional view of an embodiment of a canned motor according to the present invention. 2 is a partial cross-sectional view of a stator 3 and a can 5. FIG. 3 is a perspective view of an outer shape of a can 5. FIG. It is explanatory drawing of the metal mold | die which shape | molds the can 5. FIG. It is a figure explaining the production | generation of the cold slag at the time of shaping | molding, and the recessed part 52 as a cold slag pool. It is a perspective view of the external shape of the can 5a provided with the reinforcement rib 59. FIG. It is a fragmentary sectional view explaining the mounting state of the can 5a provided with the reinforcing rib 59. 3 is a cross-sectional view of a canned motor pump 60 combined with an internal gear pump 61. FIG. 4 is a cross-sectional view of a pump portion of the internal gear pump 61. FIG. It is sectional drawing of the can 5b which is a deformation | transformation embodiment. It is sectional drawing of the canned motor 1a using the can 5b which is a deformation | transformation embodiment. FIG. 2 is a view corresponding to FIG.

Explanation of symbols

  In the drawings, 1, 1a is a canned motor, 2 is a motor frame, 3 is a stator, 4 is a rotor, 5 is 5a, 5b is a resin can, 6 is a flange, 10 is a driven device, and 13 is a stator core. , 16 is a coil winding slot, 17 is an opening, 20 is a coil (armature winding), 35 is a stator side space, 36 is a rotor side space, 39 is a rotating shaft, and 41 is an input rotating shaft (shaft). ), 44 is an upper mold, 45 is a lower mold, 48 is a sprue, 49 is an opening, 52 is a recess, 53 is a cavity, 56 is a projection, 57 is an air gap, 59 is a reinforcing rib, and 60 is a canned motor. A pump 61 is a pump (internal gear pump).

Claims (6)

A stator side space (35) and a rotor side space (36) disposed in an air gap (57) between the stator (3) and the rotor (4) having the rotation shaft (39) in the canned motor. A canned motor resin can (5) molded from a liquid crystal polymer resin having a bottomed cylindrical shape and a flange (28) for fixing at the periphery of the open end. A can made of resin for a can motor , wherein a convex portion (56) having a cold slug formed of the liquid crystal polymer resin is provided to protrude toward the rotating shaft inside the can. 2. The can of the can motor according to claim 1, wherein the can is disposed on an outer peripheral portion of the cylindrical portion and extends in an axial direction, and the stator core of the stator is attached to the canned motor. A resin can for a can motor , characterized in that an elongated reinforcing rib (59) that fits into an opening (17) of a coil winding slot (16) provided in (13) is projected . An injection mold for molding the resin can for a can motor according to claim 1 or 2 by injection molding, wherein an upper mold (44) for molding the outer surface of the can and a lower mold (for molding the inner surface). 45), and the upper die has an opening (49) of a sprue (48) for injecting a molten resin into the cavity (53) at the center of the portion forming the cylindrical bottom surface, An injection mold characterized in that a recess (52) functioning as a cold slag reservoir is provided in the lower mold part facing the part. A method for producing a resin can for a can motor, wherein the upper mold and the lower mold in the injection mold according to claim 3 are closed and molten resin is injected through the sprue. A stator (3) formed by winding a coil (20) around a stator core (13) is fitted and fixed to the inner periphery of a bottomed cylindrical motor frame (2), and a bottom is provided inside the stator. A canned motor in which a cylindrical can (5) is disposed and a rotor (4) is rotatably disposed therein,
The resin can for a canned motor according to claim 1 or 2 is fixed to the motor frame so as to separate and block the stator side space (35) and the rotor side space (36), and the rotor is a rotating shaft. A canned motor characterized in that (39) is connected directly to an input rotating shaft (41) of a driven device (10) of the canned motor and is rotated while supported by the input rotating shaft. A canned motor pump, wherein the driven device (10) driven by the canned motor according to claim 5 is a pump, and the pump and the canned motor are integrally formed.

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