JP6625447B2 - Motor pump - Google Patents

Description

  The present invention relates to a motor pump that rotates an impeller in which a permanent magnet is embedded by a magnetic field generated by a motor stator.

  As a conventional example of a motor pump that rotates an impeller in which a permanent magnet is embedded by a magnetic field generated by a motor stator, a pump described in Patent Literature 1 is known. The motor pump described in Patent Document 1 has an impeller in which a permanent magnet is buried, and a motor stator disposed to face the impeller, and the impeller is rotatably supported by one spherical bearing. Have been. The spherical bearing is a so-called dynamic pressure bearing, and is capable of supporting the impeller rotatably and tiltably.

  The motor stator has a plurality of stator coils. When a three-phase current flows through these stator coils, a rotating magnetic field is generated. This rotating magnetic field acts on a permanent magnet embedded in the impeller, and drives the impeller to rotate. The motor stator is housed in a motor casing, and the motor casing is generally made of resin. The motor casing made of resin has the advantage that even if the stator coil contacts the motor casing, the electrical insulation of the stator coil is maintained and there is no risk of ground fault.

  When a current is applied to the stator coil, the stator coil generates heat. When the motor casing is made of resin, it is difficult to efficiently dissipate the heat generated in the stator coil from the motor casing because the resin has a low thermal conductivity. In particular, when the current flowing through the stator coil increases, the calorific value of the stator coil also increases, so that the temperature of the stator coil excessively increases. Since an excessive rise in the temperature of the stator coil leads to deterioration and breakage of the stator coil, a temperature limit is provided for the motor stator including the stator coil. Due to the temperature limitation of the motor stator, the operating range of the motor pump is limited. Therefore, there is a need for a technique that can effectively suppress a rise in the temperature of the motor stator in order to expand the operating range of the motor pump.

Japanese Patent No. 2544825

  The present invention has been made in view of the above-described conventional problems, and has as its object to provide a motor pump that can effectively suppress a rise in the temperature of a motor stator.

In order to achieve the above-described object, one embodiment of the present invention provides a motor stator having an impeller in which a permanent magnet is embedded, a stator core wound with a plurality of stator coils, and the motor stator. , A suction port connected to a liquid flow path formed in the motor casing and made of metal, and contacting the stator core and the suction port, and having a higher heat conduction than the motor casing. A suction member, the suction port having a cylindrical base, and a cylindrical shaft having a smaller diameter than the base. And the motor casing .

In a preferred aspect of the present invention, the heat radiating member is made of metal or ceramic.
A preferred embodiment of the present invention, on the outer peripheral surface of the front Kijiku portion, the screw portion is formed, to the motor casing, a screw hole is formed, the threaded portion is inserted into the screw hole Tei It is characterized by that.

In a preferred aspect of the present invention, a cooling chamber through which a cooling liquid flows is attached to the heat radiating member.
In a preferred aspect of the present invention, the heat radiation member is used as a motor cover for closing a housing space for housing the motor stator.

  According to the present invention, the heat generated by the motor stator is transmitted to the heat radiation member, and further transmitted from the heat radiation member to the suction port. Further, since the heat transmitted to the suction port is transmitted to the liquid flowing in the suction port, heat generated in the motor stator can be efficiently radiated to the outside of the motor pump. As a result, a rise in the temperature of the motor stator can be efficiently suppressed.

It is a sectional view showing the motor pump concerning one embodiment of the present invention. It is the figure which looked at the motor pump shown in FIG. 1 from the arrow A direction. It is a top view which shows the permanent magnet embedded in the impeller. FIG. 4A is a plan view showing a motor stator, and FIG. 4B is a sectional view taken along line BB shown in FIG. 4A. FIG. 4 is a diagram showing a modification in which a cooling chamber is provided in the motor pump shown in FIG. 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view showing a motor pump according to an embodiment of the present invention, and FIG. 2 is a view of the motor pump shown in FIG. The motor pump includes an impeller 1 in which a plurality of permanent magnets 5 are embedded, a motor stator 6 for generating a magnetic force acting on these permanent magnets 5, a pump casing 2 for accommodating the impeller 1, and a motor fixing device. A motor casing 3 that accommodates the child 6 and a bearing 10 that supports the radial load and the thrust load of the impeller 1 are provided. The motor stator 6 and the bearing 10 are arranged on the suction side of the impeller 1.

  The pump casing 2 and the motor casing 3 are fixed to each other by a plurality of connection bolts 8 shown in FIG. An O-ring 9 is provided between the pump casing 2 and the motor casing 3 as a seal member. The impeller 1 and the motor casing 3 are opposed to each other via a small gap, and the impeller 1 is rotated by a rotating magnetic field generated by the motor stator 6 acting on the permanent magnet 5. The gap between the impeller 1 and the motor casing 3 is preferably as small as possible without contacting each other. Specifically, it is preferable to form the gap in the range of 0.5 mm to 1 mm.

  The impeller 1 is rotatably supported by a single bearing 10. The bearing 10 is a sliding bearing (dynamic pressure bearing) using liquid dynamic pressure. The bearing 10 is composed of a combination of a rotating bearing element 11 and a fixed bearing element 12 that loosely engage with each other. The rotating bearing element 11 is fixed to the impeller 1 and is arranged so as to surround the liquid inlet of the impeller 1. The fixed bearing element 12 is fixed to the motor casing 3 and is arranged on the suction side of the rotating bearing element 11. The fixed-side bearing element 12 has a radial surface 12a that supports the radial load of the impeller 1 and a thrust surface 12b that supports the thrust load of the impeller 1. The radial surface 12a is parallel to the axis of the impeller 1, and the thrust surface 12b is perpendicular to the axis of the impeller 1.

  The rotation-side bearing element 11 has an annular shape, the inner peripheral surface of the rotation-side bearing element 11 faces the radial surface 12a of the fixed-side bearing element 12, and the side surface of the rotation-side bearing element 11 is fixed. 12 is opposed to the thrust surface 12b. A minute gap is formed between the inner peripheral surface of the rotating side bearing element 11 and the radial surface 12a, and between the side surface of the rotating side bearing element 11 and the thrust surface 12b. Further, a spiral groove (not shown) for generating dynamic pressure is formed on the inner peripheral surface and the side surface of the rotation-side bearing element 11.

  A part of the liquid discharged from the impeller 1 is guided to the bearing 10 through a minute gap between the impeller 1 and the motor casing 3. When the rotating bearing element 11 rotates together with the impeller 1, a liquid dynamic pressure is generated between the rotating bearing element 11 and the fixed bearing element 12, whereby the impeller 1 is supported by the bearing 10 in a non-contact manner. You. Since the fixed-side bearing element 12 supports the rotating-side bearing element 11 by orthogonal radial surfaces 12a and thrust surfaces 12b, the tilting of the impeller 1 is restricted by the bearing 10. The bearing 10 (the rotation-side bearing element 11 and the fixed-side bearing element 12) is formed of a material having excellent wear resistance, such as ceramic or carbon.

  A suction port 15 having a suction port 15a is fixed to the motor casing 3. The suction port 15 is made of metal such as stainless steel and is connected to a suction line (not shown). Liquid flow paths 15b, 3a, and 10a are formed in the center of the suction port 15, the motor casing 3, and the bearing 10, respectively. These liquid flow paths 15b, 3a, and 10a are connected in a line and constitute one liquid flow path extending from the suction port 15a to the liquid inlet of the impeller 1.

  The suction port 15 has a cylindrical base 15c and a cylindrical shaft 15d having a smaller diameter than the base 15c. The base 15c and the shaft 15d are integrally formed, and the shaft 15d extends from the base 15c into the motor casing 3. The central axes of the base 15c and the shaft 15d coincide with the central axis of the suction port 15, and a liquid flow path 15b is formed by the inner peripheral surfaces of the base 15c and the shaft 15d. A screw portion 15e is formed in a part of the outer peripheral surface of the shaft portion 15d, and a screw hole 3b is formed in the motor casing 3. By engaging the screw portion 15 e of the suction port 15 with the screw hole 3 b of the motor casing 3, the suction port 15 is fixed to the motor casing 3.

  The screw portion 15e is not formed on the outer peripheral surface on the distal end side of the shaft portion 15d. An annular groove 15f is provided on the outer peripheral surface of the shaft portion 15d where the screw portion 15e is not formed. An O-ring 13 that seals a gap between the motor casing 3 and the suction port 15 is disposed in the annular groove 15f.

  A discharge port 16 having a discharge port 16a is provided on a side surface of the pump casing 2, and the liquid pressurized by the rotating impeller 1 is discharged through the discharge port 16a. The motor pump according to the present embodiment is a so-called end-top type motor pump in which the suction port 15a and the discharge port 16a are orthogonal to each other.

  The impeller 1 is made of a non-magnetic material that is slippery and hard to wear. For example, a resin such as Teflon (registered trademark) or PPS (polyphenylene sulfide), or ceramic is preferably used. The pump casing 2 can also be formed from the same material as the impeller 1. Note that the rotary bearing element 11 of the bearing 10 may be omitted, a spiral groove may be formed in a part of the impeller 1, and the impeller 1 may be supported by the radial surface 12a and the thrust surface 12b of the fixed bearing element 12. .

  FIG. 3 is a plan view showing the permanent magnet 5 embedded in the impeller 1. As shown in FIG. 3, the plurality of permanent magnets 5 are arranged in a ring shape, and S poles and N poles are alternately arranged. Each of the permanent magnets 5 has a fan shape, and in the present embodiment, the number of the permanent magnets 5 is eight (ie, eight poles). As shown in FIG. 1, an annular magnet yoke (magnetic body) 19 is embedded in the impeller 1 adjacent to the plurality of permanent magnets 5. The permanent magnet 5 is arranged on the suction side of the magnet yoke 19. The permanent magnet 5 and the motor stator 6 are arranged so as to face each other, and the motor stator 6 is arranged on the suction side of the impeller 1. The motor stator 6 is arranged in the motor casing 3, and a housing space for housing the motor stator 6 is closed by a heat radiating member 20 described later. In the present embodiment, a plurality of permanent magnets 5 are provided, but the present invention is not limited to this embodiment, and one permanent magnet having a plurality of magnetic poles may be used. Specifically, one annular permanent magnet having a plurality of magnetic poles in which the S pole and the N pole are alternately magnetized may be used.

  FIG. 4A is a plan view showing the motor stator 6, and FIG. 4B is a sectional view taken along line BB shown in FIG. 4A. As shown in FIGS. 4A and 4B, the motor stator 6 includes a stator core 6A having a plurality of teeth 6a, a stator coil 6B wound around each of the teeth 6a, have. The teeth 6a and the stator coils 6B are arranged annularly. In the present embodiment, the stator coil 6B is wound around each of the six teeth 6a, and the number of magnetic poles is six. The impeller 1 and the motor stator 6 are arranged concentrically with the bearing 10.

  Three lead wires 17 (see FIG. 2) are connected to the stator coil 6B, and the terminals of the lead wires 17 are connected to a drive circuit (not shown). This drive circuit is a device that controls the timing of the current supplied to each stator coil 6B using a switching element. More specifically, the drive circuit controls the timing of the current supplied to each stator coil 6B based on the position of the rotating permanent magnet 5. Examples of a method for detecting the position of the permanent magnet 5 include a method using a position sensor such as a Hall element and a method using a back electromotive force generated in the stator coil 6B without using the position sensor. The motor pump according to the present embodiment may employ either a sensor driving method using a position sensor or a sensorless driving method without using a position sensor.

  The drive circuit described above appropriately switches the current supply to the stator coil 6 </ b> B based on the position of the permanent magnet 5, whereby the permanent magnet 5, that is, the impeller 1 rotates. When the impeller 1 rotates, the liquid is introduced into the liquid inlet of the impeller 1 from the suction port 15a of the motor pump. The liquid is pressurized by the rotation of the impeller 1 and is discharged from the discharge port 16a. While the impeller 1 is transferring liquid, the back surface of the impeller 1 is pressed toward the suction side (ie, toward the suction port 15a) by the pressurized liquid. Since the bearing 10 is arranged on the suction side of the impeller 1, the bearing 10 supports the thrust load of the impeller 1 from the suction side. According to the configuration according to the present embodiment, the radial load and the thrust load of the impeller 1 can be supported by one bearing 10 in a non-contact manner, so that a compact motor pump that does not generate particles can be realized. Can be.

  From the viewpoint of ensuring electrical insulation of the motor stator 6 and preventing generation of eddy current, the motor casing 3 is made of a non-metallic material. As a material constituting the motor casing 3, a resin is preferably used. More specifically, inexpensive resins such as PPS (polyphenylene sulfide) and PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) are used. The motor casing 3 made of resin has the advantage that even if the stator coil 6B contacts the motor casing 3, the electrical insulation of the stator coil 6B is maintained and there is no risk of ground fault. As a method of forming the motor casing 3 with a resin, injection molding is exemplified.

  As shown in FIG. 1, the side wall portion 32 of the motor casing 3 is arranged to face the suction-side side surface of the impeller 1. That is, the side wall portion 32 is located between the impeller 1 and the stator coil 6B, and functions as a partition separating the impeller 1 and the motor stator 6. The rotating magnetic field generated by the motor stator 6 reaches the permanent magnet 5 of the impeller 1 through the side wall 32. Therefore, it is preferable that the side wall 32 of the motor casing 3 is as thin as possible. For example, the side wall 32 of the motor casing 3 has a thickness of several mm.

  As shown in FIG. 1, the motor pump of the present embodiment is provided with a heat radiation member 20 that contacts the stator core 6 </ b> A of the motor stator 6 and the suction port 15. The heat radiating member 20 is made of a material having a higher thermal conductivity than the motor casing 3. Such a material is, for example, a metal such as stainless steel or aluminum, or a ceramic.

  The motor stator 6 is housed in a housing space formed in the motor casing 3, and the housing space is closed by a heat radiation member 20 as shown in FIG. Therefore, the heat radiating member 20 of the present embodiment is used as a motor cover for closing the accommodation space of the motor stator 6. The heat dissipating member 20 includes a cover plate 20a for closing the accommodation space of the motor stator 6, and a fixing ring 20b protruding from the surface of the cover plate 20a toward the motor stator 6. The cover plate 20a and the fixing ring 20b are formed integrally. The cover plate 20a and the fixing ring 20b constituting the heat radiation member 20 may be separate members. Also in this case, both the cover plate 20a and the fixing ring 20b are made of a material having a higher thermal conductivity than the motor casing 3.

  The cover plate 20a has a disk shape as a whole, and a hole into which the suction port 15 is inserted is formed at the center thereof. The screw portion 15e of the suction port 15 is inserted into the screw hole 3b of the motor casing 3, and a part of the cover plate 20a of the heat radiation member 20 is sandwiched between the base 15c of the suction port 15 and the motor casing 3. I have. In this state, the fixing ring 20b of the heat radiation member 20 is in contact with the stator core 6A of the motor stator 6, and presses the motor stator 6 against the side wall 32 of the motor casing 3. As described above, the heat dissipation member 20 of the present embodiment functions as a fixing member that contacts the stator core 6A and the suction port 15 and fixes the position of the motor stator 6.

  When a current flows through the stator coil 6B of the motor stator 6, the stator coil 6B generates heat. Part of the heat is transmitted to the liquid via the side wall 32 of the motor casing 3, and another part is dissipated to the outside air via the motor casing 3 and the heat radiating member 20. The heat generated in the motor stator 6 contacts the stator core 6A of the motor stator 6 and is transmitted to the heat radiating member 20 having a higher thermal conductivity than the motor casing 3, and the heat radiating member 20 efficiently removes the outside air. Dissipated to

  Further, the heat radiating member 20 is in contact with the suction port 15. Since the suction port 15 is made of metal, it has a high thermal conductivity. Therefore, the heat transmitted from the heat radiation member 20 to the suction port 15 is efficiently radiated from the suction port 15 to the outside air. Further, the suction port 15 is in contact with the liquid flowing in the liquid flow path 15b. Therefore, the heat transmitted to the suction port 15 is transmitted to the liquid flowing in the liquid flow path 15b. As a result, the heat generated by the motor stator 6 can be further efficiently radiated to the outside of the motor pump, so that a rise in the temperature of the motor stator 6 can be efficiently suppressed.

  As described above, the heat generated in the motor stator 6 is transmitted to the liquid flowing in the motor pump via the heat radiation member 20 and the suction port 15, so that the temperature of the liquid flowing in the motor pump increases. Therefore, it is preferable that the temperature of the liquid discharged from the motor pump be adjusted by a device to which the liquid is supplied. Such an apparatus is, for example, a semiconductor manufacturing apparatus, a processing machine, or an air conditioner.

  In order to further improve the cooling efficiency of the motor stator 6, a cooling chamber 40 may be provided in the heat radiating member 20, as shown in FIG. FIG. 5 is a view showing a modification in which a cooling chamber 40 is provided in the motor pump shown in FIG. As shown in FIG. 5, the cooling chamber 40 is attached to the outer surface of the heat radiating member 20. The cooling chamber 40 has an annular shape, and has a cooling liquid inlet 40A and a cooling liquid outlet 40B. The cooling liquid (for example, cooling water) flows into the cooling chamber 40 from a cooling liquid supply source (not shown) through the cooling liquid inlet 40A, flows inside the cooling chamber 40, and is discharged from the cooling liquid outlet 40B. According to such a configuration, the heat generated in the motor stator 6 is transmitted to the coolant through the heat radiating member 20, so that the heat of the motor stator 6 can be more efficiently released to the outside of the motor pump.

  The motor pump described with reference to FIGS. 1 to 5 is a so-called end-top type motor pump in which a suction port and a discharge port are orthogonal to each other, but is an in-line type in which a suction side pipe, a discharge port, and an impeller are arranged in a straight line. The present invention is applicable to a motor pump.

  The above embodiments have been described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to carry out the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the embodiments described, but is to be construed in its broadest scope in accordance with the spirit defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 Impeller 2 Pump casing 3 Motor casing 5 Permanent magnet 6 Motor stator 10 Bearing 11 Rotating side bearing element 12 Fixed side bearing element 15 Suction port 16 Discharge port 20 Heat dissipation member 32 Side wall (partition wall)
40 cooling room

Claims (5)

An impeller with embedded permanent magnets,
A motor stator having a stator core wound with a plurality of stator coils,
A motor casing containing the motor stator;
A suction port connected to a liquid flow path formed in the motor casing, and made of metal;
A heat dissipating member made of a material having a higher thermal conductivity than the motor casing, the heat dissipating member being in contact with the stator core and the suction port ;
The suction port has a cylindrical base and a cylindrical shaft having a smaller diameter than the base,
A motor pump , wherein the heat dissipation member is sandwiched between the base and the motor casing .   The motor pump according to claim 1, wherein the heat radiating member is made of metal or ceramic. The outer peripheral surface of the front Kijiku portion and the screw portion is formed,
A screw hole is formed in the motor casing,
Motor pump according to claim 1 or 2 wherein the threaded portion is characterized by Tei Rukoto is inserted into the screw hole.   The motor pump according to any one of claims 1 to 3, wherein a cooling chamber through which a cooling liquid flows is attached to the heat radiating member.   The motor pump according to any one of claims 1 to 4, wherein the heat radiating member is used as a motor cover that closes a housing space that houses the motor stator.

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