Pump device

Abstract

The present invention improves the ease of processing.　A pump device (1) comprises: a rotor (20) as a rotating body that rotates about a shaft (40); and a stator (90) that surrounds the rotor (20). The rotor (20) is provided with an impeller (21), a rotor core (22), and a rotor magnet (30) as a magnet attached to the rotor core (22). The rotor core (22) is provided with a flange (24) having a protrusion (221) that protrudes toward the rotor magnet (30) in the axial direction of the shaft (40). The rotor magnet (30) has a recess (301) that contacts the protrusion (221), and a gate mark is formed in the recess (301).

Description

Pump device

[0001] The present invention relates to a pump device.

[0002] There has been known a pump device that circulates liquid by rotating an impeller with a motor, wherein the rotor is provided with a seat portion as a flange that receives one end face of a magnet (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Publication No. 2010-246239

[0004] The rotor is formed from a magnet and an impeller. It is necessary to provide rotation prevention for the magnet relative to the rotor. In addition, when molding a rotor including an injection-molded impeller and a magnet, irregularities are generated due to gate breakage, which causes processes for checking flatness and removing protrusions.

[0005] The present invention has been made in view of the above problems, and enables simpler rotor molding and provides a rotation prevention function for the magnet during rotor rotation.

[0006] In order to achieve the above object, the pump device according to the present invention includes a rotating body that rotates around a rotation shaft, and a stator that surrounds the rotating body. The rotating body includes an impeller, a rotor core, and a magnet attached to the rotor core. The rotor core includes a flange having a protrusion protruding toward the magnet in the axial direction of the rotation shaft. The magnet has a recess in contact with the protrusion, and a gate mark is formed in the recess.

[0007] According to the pump device of the present invention, it has a rotation prevention function for the rotor magnet, and further can improve the ease of processing.

[0008] This is an exploded perspective view schematically showing the configuration of a pump device according to an embodiment of the present invention. This is a perspective view schematically showing the configuration of the rotor of the pump device according to this embodiment, showing the view from the impeller side. This is a perspective view schematically showing the configuration of the rotor of the pump device according to this embodiment, showing the view from the magnet side. This is a cross-sectional view schematically showing the configuration of the rotor of the pump device according to this embodiment. This is an enlarged cross-sectional view schematically showing the configuration of the rotor of the pump device according to this embodiment. This is a bottom view schematically showing the configuration of the rotor core in the rotor of the pump device according to this embodiment. This is a perspective view schematically showing the configuration of the magnet in the rotor of the pump device according to this embodiment.

[0009] Hereinafter, a pump device according to an embodiment of the present invention will be described with reference to the drawings.

[0010] Figure 1 is an exploded perspective view schematically showing the configuration of a pump device 1 according to an embodiment of the present invention. Figure 2 is a perspective view schematically showing the configuration of the rotor 20 of the pump device 1, and is a perspective view showing the state as seen from the impeller 21 side. Figure 3 is a perspective view schematically showing the configuration of the rotor 20 of the pump device 1, and is a perspective view showing the state as seen from the rotor magnet side. Figure 4 is a cross-sectional view schematically showing the configuration of the rotor 20 of the pump device 1. Figure 5 is an enlarged cross-sectional view schematically showing the configuration of the rotor 20.

[0011] In the following explanation, for convenience, the direction indicated by the y-axis arrow in Figure 1 (+y-axis direction) will be considered the upper side, and the opposite direction of the arrow (-y-axis direction) will be considered the lower side. In the pump device 1, the y-axis direction is the axis direction of the shaft 40 as the axis of rotation. In the radial direction perpendicular to the axis direction of the shaft 40, that is, in the x-axis direction or z-axis direction, the direction away from the shaft 40 will be considered the outer side, and the direction toward the shaft 40 will be considered the inner side. The direction around the shaft 40 will be considered the circumferential direction. In the following explanation, the surface viewed from the radially outer side of the shaft 40 will be considered the side surface of the pump device 1. Also, in the following explanation, for convenience, the direction in which the pump device 1 is viewed from the top to the bottom will be considered the plane, and the direction in which it is viewed from the bottom to the top will be considered the bottom surface.

[0012] As shown in Figure 1, the pump device 1 according to this embodiment comprises a rotor 20 as a rotating body that rotates around a shaft 40, and a stator 90 surrounding the rotor 20. As shown in Figures 2 to 5, the rotor 20 comprises an impeller 21, a rotor core 22, and a rotor magnet 30 as a magnet attached to the rotor core 22. As shown in Figures 4 and 5, the rotor core 22 has a flange 24 having a convex portion 221 that protrudes toward the rotor magnet 30 in the axial direction of the shaft 40, and the rotor magnet 30 has a recess 301 that contacts the convex portion 221, and a gate mark is formed in the recess 301. The configuration and operation of the pump device 1 will be described in detail below.

[0013] [Pump device configuration] As shown in Figure 1, the pump device 1 includes, in addition to the rotor 20, rotor magnet 30, and stator 90 described above, a case 10, a shaft 40, a bearing portion 50, an O-ring 16, and a cover 60.

[0014] The case 10 is positioned on the +y-axis side of the pump device 1. The case 10 is made of, for example, resin. The case 10 includes a suction port 11 for taking liquid into the pump device 1 and a discharge port 12 for discharging the liquid inside the pump device 1. The liquid is, for example, a known coolant such as propylene glycol. The type of liquid circulated in the pump device 1 is not limited.

[0015] The case 10 is fixed to the cover 60 in a watertight manner via an O-ring 16 in the y-axis direction, thereby forming the external appearance of the pump device 1. The O-ring 16 is a substantially annular member formed of an elastic resin such as rubber. The case 10 may also be fixed to the cover 60 by spin welding, in which case an O-ring may not be provided.

[0016] The cover 60 is, for example, a cup-shaped resin member that opens in the +y axis direction. The stator core 70 and coil 80 of the stator 90 are housed inside the inner wall 63 of the cover 60. A hole or recessed fixing part for supporting the shaft 40 is formed in the bottom of the cover 60.

[0017] The stator core 70 has a cylindrical shape that extends in the y-axis direction from the shaft 40 and surrounds the inner wall 63 of the cover 60. The stator core 70 has a magnetic member (an example of a magnetic material). The magnetic member is formed from a plate-shaped metal member such as a silicon steel sheet or an electromagnetic steel sheet. For example, the stator core 70 is formed by stacking multiple such plate-shaped metal members in the direction of the rotation axis.

[0018] The stator core 70 comprises a yoke and a plurality of teeth. The teeth extend radially inward from the inner circumference of the yoke. The stator core 70 also includes a plurality of coils 80 and an insulator 73. The stator core 70 is formed from a laminate of a plurality of thin plates stacked in the axial direction. The laminate is made of a magnetic material. The coils 80 have windings, for example, made of copper wire. The insulator 73 electrically insulates the stator core 70 from the plurality of coils 80. The insulator 73 is made of an insulating material, for example, a resin material.

[0019] In the radial direction, a magnetic gap is formed between the teeth of the stator core 70 and the rotor magnet 30. That is, the stator core 70 generates a magnetic field for rotating the rotor magnet 30 by sequentially energizing the coils 80 wound around the teeth with an externally supplied current. As a result, the rotor magnet 30 rotates around the shaft 40 as its axis of rotation due to the magnetic field generated by the stator core 70.

[0020] The rotor 20 comprises an impeller 21, a rotor core 22, and a rotor magnet 30.

[0021] Figure 6 is a schematic bottom view showing the configuration of the rotor core 22.

[0022] As shown in Figures 3, 4, and 6, the rotor core 22 in the rotor 20 has a core body 23, a flange 24, and a retaining portion 25. The rotor core 22 is injection molded by pouring resin material into a mold.

[0023] The impeller 21 is provided on the rotor 20 on the +y-axis side of the shaft 40. The impeller 21 has a radially extending base portion 211 and a plurality of rotor blades 212 extending axially from the base portion 211. The shape of the impeller 21, such as the shape and number of rotor blades 212, is not limited in the pump device 1.

[0024] The core body 23 is located on the rotor 20 on the opposite side of the impeller 21 in the axial direction of the shaft 40, that is, on the -y-axis side. In other words, the impeller 21 and the core body 23 face each other in the axial direction.

[0025] The core body 23 is formed in a cylindrical or substantially cylindrical shape around the axis which is the central axis of the shaft 40. The outer circumferential surface of the core body 23 is in contact with the inner circumferential surface 33 of the rotor magnet 30.

[0026] The flange 24 is provided at the upper end of the core body 23, that is, at the end of the core body 23 on the +y axis side. The flange 24 protrudes radially outward from the outer circumferential surface of the core body 23 in the rotor core 22. The flange 24 has a protrusion 221 that protrudes in the axial direction.

[0027] The protrusions 221 are provided on the lower surface 241 of the flange 24, which is the surface facing the rotor magnet 30. The protrusions 221 project axially toward the rotor magnet 30, that is, downward from the lower surface 241 of the flange 24. The number of protrusions 221 is provided in proportion to the number of recesses 301, for example, four. The protrusions 221 are provided at predetermined intervals in the circumferential direction, for example, at 90° intervals, but there is no fixed number or number of installations. There can be any number of protrusions 221 as long as the intervals between them are even, and furthermore, there may be an odd number of protrusions 221.

[0028] The retaining portion 25 is provided at the lower end of the core body 23, that is, at the end of the core body 23 on the -y-axis side. The retaining portion 25 protrudes radially outward from the outer circumferential surface of the core body 23. Any number of retaining portions 25, for example, four, are provided. The shape and number of retaining portions 25 are not limited to the examples shown in Figures 3 and 6.

[0029] Figure 7 is a schematic perspective view showing the configuration of the rotor magnet 30 in the rotor 20.

[0030] The rotor magnet 30 is mounted radially outward of the rotor core 22 on the rotor 20. The rotor magnet 30 is, for example, a rare-earth bonded magnet such as a neodymium magnet with high magnetic properties. The rotor magnet 30 is injection molded by pouring rare-earth bonded magnet material into a mold. The rotor core 22 and the rotor magnet 30 constitute the rotor.

[0031] The rotor magnet 30 has a through hole in its center that penetrates axially, and is formed in a cylindrical or substantially cylindrical shape having an outer circumferential surface 32 and an inner circumferential surface 33. In the rotor magnet 30, the outer circumferential surface 32 and the inner circumferential surface 33 become the surfaces in the mold's removal direction, i.e., sliding surfaces, during injection molding. For this reason, the outer circumferential surface 32 and the inner circumferential surface 33 may be tapered surfaces having a draft angle that widens as it moves in the y-axis direction.

[0032] The rotor magnet 30 has an upper surface 34, which is the side facing the impeller 21 in the axial direction of the shaft 40, and a lower surface 35, which is the side facing the opposite side of the impeller 21, i.e., the lower surface. The lower surface 35 is formed as a smooth surface. The smoothness of the lower surface 35 facilitates sliding when the pump device 1 rotates.

[0033] The upper surface 34 has recesses 301. There are four recesses 301, corresponding to the number of protrusions 221. The recesses 301 are provided in a number that corresponds to the number of protrusions 221, for example. The recesses 301 are provided in a number that corresponds to the positions where the protrusions 221 are provided, for example, at 90° intervals in the circumferential direction. Therefore, the recesses 301 are in contact with the protrusions 221 provided on the flange 24 of the rotor core 22. Note that the recesses 301 are not limited to the above configuration and may be provided at uneven intervals. Also, the number of recesses 301 may be even or odd.

[0034] As shown in Figure 5, the upper surface 34 comprises a first surface 311, a second surface 312, and a third surface 313. On the upper surface 34, the first surface 311 and the third surface 313 form a recess 301 into which the resin constituting the impeller 21 and rotor core 22 flows, forming a protrusion 221 that functions as an anti-rotation mechanism when the rotating body rotates. In addition, the inner circumferential surface 33 of the rotor magnet 30 may be provided with, for example, a linearly formed alignment. Similarly, the rotor magnet 30 may be provided with a positioning hole for the rotor core 22, and this positioning hole may also have an anti-rotation function as the resin forming the rotor core 22 flows into it in the same way as the recess 301.

[0035] The first surface 311 has a lower height in the axial direction of the shaft 40 than the second surface 312. The first surface 311 is formed by the gate mark (gate mark) left by the mold used to pour material into the mold when forming the rotor magnet 30. In other words, a gate mark (first surface 311) is formed in the recess 301.

[0036] The first surface 311 may be higher or lower than the third surface 313, or it may be the same as the third surface 313, in the axial direction of the shaft 40.

[0037] The second surface 312 may be provided on either side of the first surface 311 in the radial direction of the upper surface 34.

[0038] The third surface 313 is provided between the first surface 311 and the second surface 312 in the radial direction of the upper surface 34. The third surface 313 is formed by protruding around the gate of the mold. The height of the third surface 313 in the axial direction of the shaft 40 is lower than that of the second surface 312, and the radial dimensions of the second surface 312 and the number of gate marks are not relevant, as long as the third surface 313 is a recess created during the injection molding of the rotor magnet 30. The third surface 313 is a mold transfer surface formed around the gate marks of the first surface 311. The height of the third surface 313 may be the same as or approximately the same as the first surface 311, or it may be higher or lower than the first surface 311. Also, the third surface 313 may be larger or smaller than the second surface 312 in the axial direction. The radial dimensions are not relevant, as long as it is created during the injection molding of the rotor magnet 30.

[0039] The inner circumferential surface 26 of the rotor 20 is fixed to bearings 5a and 5b that constitute the bearing section 50. The bearings 5a and 5b of the bearing section 50 rotatably support the shaft 40. The configuration is not limited to this, and there may be only one bearing. Also, the bearing may be a ball bearing or a sliding bearing.

[0040] The rotor 20 rotates in conjunction with the rotor magnet 30, drawing in liquid from the suction port 11 and discharging liquid from the discharge port 12. At this time, the protrusion 221 of the rotor core 22 on the rotor magnet 30 functions as an anti-rotation device. In this embodiment, the pressure of the rotor 20 rotating in conjunction with the rotor magnet 30 draws in a liquid (not shown), such as coolant, from the suction port 11 and discharges it from the discharge port 12. At this time, as shown in Figure 4, the rotor magnet 30 and rotor 20 housed in the cover 60 are immersed in the liquid flowing inside the pump device 1. On the other hand, the inner wall 63 of the cover 60 prevents the liquid from coming into contact with the stator core 70 and coil 80.

[0041] In the pump device 1 described above, the liquid drawn into the pump device 1 from the suction port 11 is diffused radially outward by the pressure of the rotating impeller 21. In addition, in the pump device 1, a portion of the liquid flows into the space between the bearing portion 50 and the shaft 40. The liquid that flows into this space flows in the -y axis direction and flows into the space between the impeller 21 and rotor magnet 30 and the bottom of the cover 60. The liquid that flows between the impeller 21 and rotor magnet 30 and the bottom of the cover 60 is drawn up into the space between the cover 60 and the rotor magnet 30. In the pump device 1, the liquid is discharged radially outward by the pressure generated by the rotating impeller 21.

[0042] [Molding Procedure for Rotating Body] Next, the molding procedure for the rotor 20 in the pump device 1 having the configuration described above will be explained.

[0043] The first surface 311 is located on the surface where the gate was provided during injection molding of the rotor magnet, and corresponds to the cut surface of the runner. In the molding procedure of the rotor 20, first, the material of the rotor magnet 30 is poured into a mold, and the rotor magnet 30 is molded by injection molding. At this time, by arranging a mold larger than the gate mark at the material injection port, a recess larger than a normal gate mark can be formed in the rotor magnet 30. Here, the gate portion of the mold is a valve gate in which a gate pin that closes the gate hole opens during material injection to allow the material to flow into the mold, and the gate pin closes the gate hole after injection. In the mold, the portion where the gate hole is formed is made of cemented carbide. Further, in hot runner molding, the gate pin is formed of high-speed steel, and has a hardness of, for example, HRC 62 to 63, which is lower than the hardness of the cemented carbide used for the portion where the gate hole is formed. By making the hardness of the gate pin side lower than the hardness of the gate hole, the gate pin side is worn rather than the gate hole. Since the diameter of the pin is not related to the flow rate during injection, this approach makes it possible to stably control the flow rate of each hole of the multi-point gate over a long period of time. Next, in the molding procedure of the rotor 20, the molded rotor magnet 30 is arranged such that the gate mark of the rotor magnet 30 faces the side where resin is injected into the mold of the rotor core 22, and the material of the rotor core 22 is poured into the mold for injection molding. This allows the material of the rotor core 22 to flow into the gate mark.

[0044] As described above, for the rotor 20 in the pump device 1, the rotor core 22 and the rotor magnet 30 can be integrally formed by insert molding. Here, in the rotor core 22, the gate for flowing the material into the mold during molding is provided above the recess 301 which is the gate mark of the rotor magnet 30. Further, the gate of the rotor core 22 is provided, for example, on the outer edge portion 213 of the inner peripheral surface 26 in the base portion 211 of the impeller 21. It should be noted that the gate of the rotor core 22 is not limited to the position of the above-mentioned outer edge portion 213 as long as it is located above the recess 301 which is the gate mark of the rotor magnet 30.

[0045] When molding the rotor core 22, the material of the rotor core 22 is injection-molded from the upper surface 34 side, which is the end surface of the gate of the rotor magnet 30. That is, the direction in which the resin constituting the rotor magnet 30 is injected into the mold is the same as the direction in which the resin constituting the rotor 20 is injected. In other words, in the molding process of the rotor 20, the flow direction of the material for the rotor magnet 30 is the same as the flow direction of the material for the rotor core 22.

[0046] When molding the rotor core 22, the resin forming the rotor core 22 flows into the recess 301 provided in the insert-molded rotor magnet 30, forming the protrusion 221 of the rotor core 22. The recess 301 is a recess formed by a third surface 313 between the first surface 311, which is a gate mark, and a second surface 312 around the first surface 311.

[0047] As described above, in the rotor 20 of the pump device 1 according to the present embodiment, the recess 301 is formed in the rotor magnet 30.

[0048] According to the rotor 20 including the rotor magnet 30 having the recess 301, by providing the recess 301 around the first surface 311 which is the gate mark of the rotor magnet 30, the unevenness generated at the gate mark, particularly the convex shape, can be accommodated inside the recess 301. Thereby, the rotor has a function as a rotation stopper.

[0049] Furthermore, in the rotor 20, by providing the recess 301 around the first surface 311 of the rotor magnet 30, even if burrs are generated around the gate, the burrs can be accommodated inside the recess 301. This eliminates the need for a deburring process and enables easy molding. Furthermore, in the rotor 20, since the gate side of the rotor magnet 30 is covered with the rotor core 22 by insert molding, burrs around the gate generated during molding of the rotor magnet 30 can be sealed by the rotor core 22.

[0050] Furthermore, in the rotor 20, since the gate mark is arranged inside the recess 301, the allowable range for the height of the gate mark is wider than in the conventional art, whereby the cost of the polishing process for removing the gate mark can be reduced and the process can be simplified.

[0051] Furthermore, by adopting the above-described configuration, the rotor 20 in the pump device 1 according to this embodiment allows for a larger tolerance in the height of the rotor magnet 30, thereby improving yield.

[0052] Furthermore, in the pump device 1 according to this embodiment, the rotor 20 has a recess 301 in the rotor magnet 30 that functions as a rotation stopper for the rotor magnet 30 relative to the rotor core 22.

[0053] Therefore, the pump device 1 having a rotor magnet 30 provided with a recess 301 improves ease of processing and also allows the rotor magnet 30 to function as an anti-rotation device during rotation.

[0054] Furthermore, those skilled in the art may modify the present invention as appropriate in accordance with prior art knowledge. Such modifications, insofar as they still possess the configuration of the present invention, are of course included within the scope of the present invention.

[0055] For example, the coil 80 may be configured such that a pre-wound bobbin coil is fitted onto the teeth.

[0056] For example, in the rotor 20, the impeller 21 and the rotor core 22 are integrally molded from, for example, resin, but are not limited to this, and the rotor core 22 may be fixed to the impeller 21 which is formed separately.

[0057] 1...Pump device, 5a, 5b...Bearings, 10...Case, 11...Suction port, 12...Discharge port, 16...O-ring, 20...Rotor, 21...Impeller, 22...Rotor core, 23...Core body, 24...Flange, 25...Retaining part, 26...Inner surface, 30...Rotor magnet, 32...Outer surface, 33...Inner surface, 34...Top surface, 35...Bottom surface, 40...Shaft, 50...Bearing part, 60...Cover, 63...Inner wall, 70...Stator core, 73...Insulator, 80...Coil, 90...Stator, 211...Base part, 212...Motor blades, 213...Outer edge part, 221...Convex part, 241...Bottom surface, 301...Concave, 311...First surface, 312...Second surface, 313...Third surface

Claims

1. A pump device comprising: a rotating body that rotates around a rotation axis; and a stator surrounding the rotating body, wherein the rotating body comprises an impeller, a rotor core, and a magnet attached to the rotor core, the rotor core having a flange having a protrusion projecting toward the magnet in the axial direction of the rotation axis, the magnet having a recess in contact with the protrusion, and a gate mark formed in the recess.

2. The pump device according to claim 1, wherein the magnet has a surface on the impeller side and a surface on the opposite side of the impeller in the axial direction of the rotating shaft, the surface on the impeller side has the recess formed thereon, and the surface on the opposite side of the impeller is a smooth surface.

3. The pump device according to claim 1 or 2, wherein the surface of the magnet on the impeller side comprises a first surface formed by the gate mark in the recess and a second surface formed on the inner circumference side of the first surface, and the height of the first surface in the axial direction of the rotating shaft is lower than that of the second surface.

4. The pump device according to claim 3, wherein the magnet has a third surface between the first surface and the second surface in the radial direction of the impeller-side surface, and the height of the third surface in the axial direction of the rotating shaft is lower than that of the first surface.

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