JP2007198350A - Centrifugal pump and rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal pump having improved performance with stable magnetic detection. <P>SOLUTION: The centrifugal pump 10B comprises a rotor 15B having an impeller 150B rotatably arranged on a fixed shaft 11 extending toward a center shaft O and a ring-shaped permanent magnet 155A arranged on the inner periphery of the impeller. The impeller 150B and the permanent magnet 155A are integrally formed with insert molding. The impeller 150B has an outside cylindrical portion 154A covering the outer peripheral wall of the permanent magnet 155A. The permanent magnet 155A has a protruded portion 155a protruded from the lower end of the outside cylindrical portion 154A to the radial outside. A magnetic detection element is arranged near the lower-end outer periphery of the rotor 15B for stable magnetic detection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a centrifugal pump, and more particularly to a rotor used therefor.

  The pump is a machine that pumps liquid such as water and sucks liquid from a suction port (inlet) and discharges it from a discharge port (outlet). There are various types of pumps, and one type is known as a centrifugal pump. A centrifugal pump is a machine that rapidly accelerates and sends a liquid such as water to a spiral chamber in an outer peripheral portion by an impeller. In other words, the centrifugal pump is a machine that pumps liquid with centrifugal force obtained by rotating an impeller. Such a centrifugal pump is widely adopted as a pump type because it can obtain a high flow rate and a high head and has high efficiency.

  On the other hand, as is well known, various personal computers have been put on the market, and the personal computer incorporates a CPU, a memory, and the like. The CPU tends to increase the heat generated during operation as the clock frequency increases. Therefore, it is necessary to discharge the heat generated by the CPU to the outside.

  Conventionally, an air cooling system in which a heat sink and an air cooling fan are combined is generally used as a heat exhaust mechanism of a CPU. However, a personal computer employing this air cooling system has a problem that “wind noise”, which is the main cause of noise, is generated. In order to reduce such “wind noise” as much as possible, a personal computer adopting a water cooling system for cooling the CPU has been developed and attracted attention.

  The centrifugal pump described above is used to pump water in such a water cooling system. Such a centrifugal pump pumps water (liquid) supplied from a suction port (inlet) provided in the central part of the casing (casing) using the centrifugal force of the rotating impeller, It has the structure which discharges from the discharge outlet (outflow port) provided in the outer peripheral part of the housing | casing (casing).

  In the centrifugal pump having such a configuration, since the impeller needs to be rotated, the impeller is configured integrally with the rotor. The rotor is rotatably provided on a fixed shaft extending along the central axis via a bearing. Further, the rotor includes an annular permanent magnet to which a rotational driving force is applied by a magnetic field (magnetic flux) generated from the stator (see, for example, Patent Document 1). That is, the rotor (rotor) is composed of an impeller and a permanent magnet, and is disposed so as to be rotatable around a fixed shaft via a bearing.

  Hereinafter, a conventional centrifugal pump 10 will be described with reference to FIGS. 1 and 2. In the illustrated centrifugal pump 10, a DC brushless motor is employed as a motor for rotationally driving an impeller described later.

  The illustrated centrifugal pump 10 includes a fixed shaft 11 extending in a predetermined center axis O direction (vertical direction in the illustrated example) at the center of a housing (described later). The fixed shaft 11 includes a bearing 13. The rotor 15 is rotatably attached through the. The rotor 15 is rotatably attached to the bearing 13 and extends in an inner cylindrical portion 151 extending in the direction of the central axis O, and an upper end of the inner cylindrical portion 151 in a direction perpendicular to the central axis O direction (radially outward). And an annular permanent magnet 155 concentric with the fixed shaft 11 and fixed to the outer peripheral end of the lower surface of the annular portion 153. The permanent magnet 155 is magnetized in the circumferential direction.

  The lower end of the fixed shaft 11 is fixed to a substantially circular flat plate-like substrate 17 extending in a direction orthogonal to the central axis O direction (outside in the radial direction) via a support portion of a lower case described later. On the main surface (upper surface) 17a of the substrate 17, a stator 19 of a DC brushless motor is fixedly attached. The stator 19 includes a plurality of stator cores 191 extending radially around the fixed shaft 11 and a stator coil 193 wound around each of the plurality of stator cores 191.

  A lower case 21 is disposed between the stator 19 and the rotor 15. More specifically, the lower case 21 faces the substantially cylindrical lower support portion 211 that fixes and supports the lower end portion of the fixed shaft 11 and the lower surface of the cylindrical portion 151 of the rotor 15 with a predetermined space therebetween. The first annular portion 212 extending radially outward from the upper end portion side of the lower support portion 211 and the outer peripheral surface of the cylindrical portion 151 of the rotor 15 are opposed to each other with a predetermined space therebetween. The upper end of the first cylindrical portion 213 is opposed to the first cylindrical portion 213 extending upward from the outer peripheral end of the annular portion 212 and the lower surface of the disc portion 153 of the rotor 15 with a predetermined space therebetween. From the outer peripheral end of the second annular portion 214 so as to face the second annular portion 214 extending radially outward from the inner peripheral surface of the permanent magnet 155 of the rotor 15 with a predetermined space therebetween. The second cylindrical portion 215 extending downward, and the permanent magnet 155 of the rotor 15 A third annular portion 216 extending radially outward from a lower end of the outer periphery of the second cylindrical portion 215, and an outer peripheral surface of the permanent magnet 155 of the rotor 15 so as to face each other with a predetermined space therebetween. The third cylindrical portion 217 extending upward from the outer peripheral end of the third annular portion 216 and the upper peripheral end of the third cylindrical portion 217 radially outward so as to face each other with a space therebetween And an extended fourth annular portion 218.

  The stator 19 is disposed in a space formed between the first cylindrical portion 213, the second annular portion 214, and the second cylindrical portion 215 of the lower case 21. On the other hand, the permanent magnet 155 of the rotor 15 is disposed in a space formed between the second cylindrical portion 215, the third annular portion 216, and the third cylindrical portion 217 of the lower case 21. . Therefore, the permanent magnet 155 of the rotor 15 and the stator 19 are disposed to face each other with the second cylindrical portion 215 of the lower case 21 interposed therebetween.

  The lower case 21 includes an annular projecting portion 219 that projects concentrically with the fixed shaft 11 from the vicinity of the inner peripheral edge of the upper surface of the fourth annular portion 213 upward. A ring-shaped seal rubber 23 is disposed on the outer peripheral wall of the annular projecting portion 219.

  A plurality of blades 157 extending radially in the radial direction about the fixed shaft 11 are fixed to the upper surface of the annular portion 153 of the rotor 15. The plurality of blades 157, the annular portion 153, and the inner cylindrical portion 151 constitute an impeller 150. In other words, the rotor 15 is constituted by the impeller 150 and the permanent magnet 155.

  The rotor 15 is disposed in a space formed between the lower case 21 described above and an upper case 25 described later.

  The structure of the upper case 25 will be described in detail with reference to FIGS. 3 to 5 in addition to FIGS. The upper case 25 has a cylindrical upper support portion 251 that fixes and supports the upper end portion of the fixed shaft 11, and is separated from the upper support portion 251 by a predetermined distance and is used for a flow path between the upper support portion 251 and the upper case portion 251. A cylindrical tube 252 forming a space, a cup-shaped portion 253 extending radially outward from the cylindrical tube 252 so as to cover the plurality of blades 157, and an upper surface of the fourth annular portion 218 of the lower case 21 And an annular part 254 that extends radially outward from the lower end of the outer periphery of the cup-like part 253.

  The upper case 25 further includes a suction pipe (inflow pipe) 256 for sucking (inflowing) liquid such as water, and a discharge pipe (outflow pipe) 257 for discharging (outflowing) liquid.

  The suction pipe (inflow pipe) 256 is disposed on the upper surface of the cup-shaped portion 253 so as to extend in a direction (radial direction or horizontal direction) perpendicular to the central axis O direction. Through the central portion of the upper case 25, the cylindrical tube 252 is connected. Accordingly, the liquid flows in the suction pipe 256 from the radially outer side to the radial inner side, is bent at the suction port 256a at a right angle in the direction of the central axis O, passes through the cylindrical pipe 252 and is led to the impeller.

  The discharge pipe (outflow pipe) 257 is disposed on the upper surface of the annular portion 254 so as to extend in a plane (horizontal plane) orthogonal to the central axis O direction, and is disposed above the discharge port (outlet) 257a. The case 25 is connected to the cup-shaped portion 253 at the outer peripheral portion. Therefore, the liquid pumped by the rotating impeller flows through the discharge pipe 257 from the outer peripheral portion of the cup-shaped portion 253 via the discharge port (outlet) 257a and is discharged along the horizontal direction.

  The upper end of the cylindrical tube 252 is closed by a disk-shaped cap 258. The annular portion 254 has an annular recess 254a on the lower surface side. The annular protrusion 219 of the lower case 21 and the ring-shaped seal rubber 23 are inserted into the annular recess 254a to seal the space sandwiched between the lower case 21 and the upper case 25. Anyway, the combination of the lower case 21 and the upper case 25 constitutes a casing (housing) for housing the rotor 15 of the centrifugal pump 10. The casing (housing) is made of resin.

  FIG. 6 shows a cross-sectional view of an assembly in which the upper case 25 and the rotor 15 are combined. With respect to the flow path from the suction pipe (inflow pipe) 256 to the impeller 150 in the upper case 25, the cylindrical pipe 252 is extended to a position close to the impeller 150 in order to avoid pressure loss due to sudden pipe expansion. ing.

  FIG. 7 is an exploded perspective view of an assembly 30 of a conventional rotor 15 and bearing 13. As described above, the impeller 150 is configured by the plurality of blades 157, the annular portion 153, and the cylindrical portion 151. In the illustrated example, the impeller 150 includes four blades 157. The rotor 15 is constituted by the impeller 150 and the annular permanent magnet 155. The bearing 13 is disposed inside the cylindrical portion 151 of the impeller 150.

  FIG. 8 is a cross-sectional view of a conventional assembly 30 of the rotor 15 and the bearing 13 when the impeller 150 includes six blades 157.

  As shown in FIG. 1, a magnetic detection element 31 as a detection element for detecting the rotational position of the rotor 15 is disposed on the upper surface 17 a of the substrate 17 in the vicinity of the outer periphery of the lower end of the rotor 15. A driving element 32 is also disposed on the upper surface 17 a of the substrate 17. A detection signal from the magnetic detection element 31 is sent to the drive element 32. In response to this detection signal, the drive element 32 switches the voltage applied to the coil 193 (the direction of the excitation current flowing therethrough), thereby rotating the rotor 15 in a predetermined rotational direction.

  As described above, the conventional rotor 15 is configured separately from the permanent magnet 155 that generates power and the impeller 150 that pushes out the liquid. Therefore, the conventional rotor 15 has a problem that an assembly error increases when the permanent magnet 155 and the impeller 150 are attached. There is also a problem that the number of parts of the rotor 15 is large. Furthermore, the adhesive strength between the permanent magnet 155 and the impeller 150 is also a problem.

  As a countermeasure, a method of insert molding a permanent magnet and an impeller can be considered (for example, see Patent Document 2).

  FIG. 9 shows a rotor 15A configured by insert molding a permanent magnet 155 and an impeller 150A. 9, (A) is a plan view of the rotor 15A, (B) is a front view of the rotor 15A, (C) is a bottom view of the rotor 15A, and (D) is a line BB in FIG. 9 (C). Sectional drawing (E) is a perspective view of rotor 15A.

  Unlike the impeller 150 of the rotor 15 shown in FIGS. 1 and 2, the impeller 150 </ b> A of the rotor 15 </ b> A shown in FIG. 9 also includes an outer cylindrical portion 154 that covers the outer peripheral wall of the permanent magnet 155.

  Various rotors in which a permanent magnet is provided on the inner periphery of the impeller are conventionally known (see, for example, Patent Document 3, Patent Document 4, and Patent Document 5). However, none of these Patent Documents 3 to 5 disclose or suggest any insert molding of the impeller and the permanent magnet.

JP 2001-153083 A JP 2003-232291 A Japanese Patent Laid-Open No. 2003-161284 JP 2003-343492 A JP 2004-190562 A

  However, in the rotor 15A configured by insert molding the permanent magnet 155 and the impeller 150A, the permanent magnet 155 is covered with an outer cylindrical portion 154 made of resin, as shown in FIG. Therefore, as shown in FIG. 10, in the centrifugal pump 10 </ b> A using the magnetic detection element 31, the distance between the magnetic detection element 31 and the permanent magnet 155 is increased. Therefore, there is a problem that the magnetic detection cannot be performed and the performance is deteriorated.

  Accordingly, an object of the present invention is to provide a centrifugal pump and a rotor used in the centrifugal pump, which can perform magnetic detection stably with a magnetic detection element and can improve performance.

  According to the first aspect of the present invention, the impeller (150B; 150C; 150D) rotatably disposed on the fixed shaft (11) extending in the direction of the central axis (O), In the centrifugal pump (10B) having a rotor (15B; 15C; 15D) having an annular permanent magnet (155A; 155B) arranged around the circumference, the impeller and the permanent magnet are integrated by insert molding. The impeller has an outer cylindrical portion (154A; 154B) that covers an outer peripheral wall of the permanent magnet, and the permanent magnet protrudes radially outward at the lower end of the outer cylindrical portion (155a). A centrifugal pump characterized in that it has 155b).

  In the centrifugal pump, the projecting portion may include a flange portion (155a) projecting over the entire circumference at the lower end of the outer cylindrical portion. Instead, a plurality of the protruding portions (155b) may be arranged at equiangular intervals at the lower end of the outer cylindrical portion. In this case, each of the plurality of protrusions (155b) includes a boundary between the magnetic poles of the rotor (15C).

  In the centrifugal pump, the impeller (150B; 150C) may include an inner cylindrical portion (151) rotatably attached to the fixed shaft (11) via a bearing (13). Instead, the impeller (150D) may be composed of an integral impeller (150D) including an inner cylindrical portion (151A) that is directly rotatably attached to the fixed shaft (11). The centrifugal pump includes a magnetic detection element (31) that detects the rotational position of the rotor in the vicinity of the outer periphery of the lower end of the rotor.

  The centrifugal pump (10B) includes casings (21, 25) for accommodating the rotor, and a stator (19) disposed on the opposing surface of the annular permanent magnet via the casing. It can be a thing.

  According to the second aspect of the present invention, the impeller (150B; 150C; 150D) rotatably disposed on the fixed shaft (11) extending in the direction of the central axis (O), and the inside of the impeller In a rotor (15B; 15C; 15D) having an annular permanent magnet (155A; 155B) arranged on the circumference, the impeller and the permanent magnet are integrally formed by insert molding, An outer cylindrical portion (154A; 154B) covering an outer peripheral wall of the permanent magnet is provided, and the permanent magnet has a protruding portion (155a; 155b) protruding radially outward at a lower end of the outer cylindrical portion. To obtain a rotor.

  In the above rotor, the projecting portion may be constituted by a flange portion (155a) projecting over the entire circumference at the lower end of the outer cylindrical portion. Instead, a plurality of the protruding portions (155b) may be arranged at equiangular intervals at the lower end of the outer cylindrical portion. In this case, each of the plurality of protrusions includes a boundary between the magnetic poles of the rotor (15C).

  In the rotor, the impeller (150B; 150C) may include an inner cylindrical portion (151) rotatably attached to the fixed shaft (11) via a bearing (13). Instead, the impeller may be composed of an integral impeller (150D) including an inner cylindrical portion (151A) that is directly rotatably attached to the fixed shaft (11).

  In addition, the code | symbol in the said parenthesis is attached | subjected in order to make an understanding of this invention easy, and it is only an example, and of course is not limited to these.

  In the present invention, the impeller and the permanent magnet are integrally formed by insert molding, the impeller has an outer cylindrical portion that covers the outer peripheral wall of the permanent magnet, and the permanent magnet protrudes radially outward at the lower end of the outer cylindrical portion. Therefore, the magnetic detection can be performed stably by the magnetic detection element, and the performance can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  With reference to FIG. 11 thru | or FIG. 13, the centrifugal pump 10B which concerns on the 1st Embodiment of this invention is demonstrated. 11 is an exploded perspective view showing an external configuration of the centrifugal pump 10B, and FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. FIG. 13 is a view showing a rotor 15B used in the centrifugal pump 10B. 13, (A) is a plan view of the rotor 15B, (B) is a front view of the rotor 15B, (C) is a bottom view of the rotor 15B, and (D) is a line FF in FIG. 13 (C). (E) is a perspective view of the rotor 15B.

  The illustrated centrifugal pump 10B has the same configuration as the conventional centrifugal pump 10 described with reference to FIGS. 1 and 2 except that the configuration of the rotor is different. Therefore, the reference numeral 15B is attached to the rotor. Also, components having the same functions as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and in the following, in order to simplify the description, they are different from the conventional centrifugal pump 10. Only the point will be described.

  As shown in FIG. 13, the rotor 15B is configured by insert molding a permanent magnet 155A and an impeller 150B, similar to the rotor 15A shown in FIG. The configuration is slightly different from the rotor 15A shown.

  That is, in the rotor 15A shown in FIG. 9, the axial lengths of the outer cylindrical portion 154 and the permanent magnet 155 of the impeller 150A are substantially the same, whereas in the rotor 15B shown in FIG. The length of the outer cylindrical portion 154A of the impeller 150B is slightly shorter than the permanent magnet 155. In other words, the outer cylindrical portion 154A of the impeller 150B has a configuration in which the lower end portion of the outer cylindrical portion 154 of the impeller 150A is deleted over the entire circumference by a predetermined thickness.

  As shown in FIG. 13, the permanent magnet 155A has a protruding portion (flange portion) 155a that protrudes radially outward at the lower end of the outer cylindrical portion 154A. In other words, the lower end of the outer cylindrical portion 154A is in contact with the flange portion 155a of the permanent magnet 155A.

  By providing the flange portion 155a on the permanent magnet 155A in this manner, as shown in FIG. 14, the distance between the magnetic detection element 31 and the permanent magnet 155A arranged near the outer periphery of the lower end of the rotor 15B is shortened. Can do. Therefore, stable magnetic detection by the magnetic detection element 31 is possible while taking advantage of the insert molding that the assembly process of the impeller 150B and the permanent magnet 155A is not required, so that the performance of the centrifugal pump 10B is also stabilized. There is an advantage.

  In addition, in the centrifugal pump 10B according to the present embodiment, the floating generated when the permanent magnet 155 and the impeller 150 are attached to each other in the conventional centrifugal pump 10 (FIGS. 1 and 2) is a permanent magnet. Since 155A and the impeller 150B are eliminated by insert molding, the rotor 15B with higher accuracy can be manufactured. Further, since the permanent magnet 155A is inserted into the mold, high dimensional accuracy can be obtained without an assembly jig. By improving the dimensional accuracy of the rotor 15B, the amount of eccentricity of the center of gravity of the rotor 15B is reduced. As a result, there are effects of reducing friction loss between the fixed shaft 11 and the bearing 13, reducing current consumption, increasing output (power), extending the service life, and reducing vibration and noise.

  Furthermore, in the conventional centrifugal pump 10 (FIGS. 1 and 2), since the permanent magnet 155 and the impeller 150 are bonded using an adhesive, the joint surface between the impeller 150 and the permanent magnet 155 is used. The strength of is weakened. On the other hand, in the centrifugal pump 10B according to the present embodiment, the permanent magnet 155A and the impeller 150B are welded by insert molding, so the strength of the joint surface between the permanent magnet 155A and the impeller 150B is strong. A wide welding area can be secured. As a result, it is possible to realize a centrifugal pump 10B that is more reliable with respect to vibration and impact of the centrifugal pump 10B. Moreover, in this Embodiment, since an adhesive agent is not used, material cost becomes cheap.

  With reference to FIG. 15, another rotor 15C used in the centrifugal pump according to the second embodiment of the present invention will be described. 15, (A) is a plan view of the rotor 15C, (B) is a front view of the rotor 15C, (C) is a bottom view of the rotor 15C, and (D) is a line GG in FIG. 15 (C). Sectional drawing (E) is a perspective view of rotor 15C.

  The rotor 15C shown in the drawing is different from the rotor 15B shown in FIG. 13 in the configuration of the impeller and the permanent magnet, as will be described later. Accordingly, reference numerals 150C and 155B are assigned to the impeller and the permanent magnet, respectively.

  In the rotor 15B shown in FIG. 13, the outer cylindrical portion 154A of the impeller 150B has its lower end portion removed over the entire circumference, and a (projecting portion) flange portion 155a of the permanent magnet 155A is provided in the removed portion. . On the other hand, in the rotor 15C shown in FIG. 15, the outer cylindrical portion 154B of the impeller 150C partially removes its lower end portion at equal angular intervals, and a plurality of the removed permanent magnets 155B A protruding portion 155b is provided. In other words, the outer cylindrical portion 154B of the impeller 150C has a plurality of protrusions 154a that protrude downward at equal angular intervals at the lower end thereof.

  In the illustrated example, as shown in FIG. 15C, the protrusions 154a at the lower end of the outer cylindrical portion 154B are provided at an angular interval of 45 °, and the plurality of protrusions 155b of the permanent magnet 155B are also 45. Provided at angular intervals of °. That is, the number of protrusions 154a of the outer cylindrical portion 154B and the number of protrusions 155b of the permanent magnet 155B are both four. The number of the protrusions 154a and the protrusions 155b is equal to the number of magnetic poles of the rotor 15C.

  In the rotor 15C having such a structure, the welding area between the permanent magnet 155B and the outer cylindrical portion 154B can be increased as compared with the rotor 15B illustrated in FIG. 13, and therefore, between the impeller 150C and the permanent magnet 155B. The strength at the joint surface can be increased.

  In the rotor 15C shown in FIG. 15, as shown in FIG. 16, the plurality of protrusions 154a of the outer cylindrical portion 154B are arranged avoiding the boundary of the magnetic poles of the rotor 15C. In other words, each of the plurality of protrusions 155b of the permanent magnet 155B includes the boundary between the magnetic poles of the rotor 15C. The reason is that the magnetic detection element 31 (see FIG. 14) can stably detect the boundary between the magnetic poles of the rotor 15C (the boundary between the N pole and the S pole).

  With reference to FIG. 17, another rotor 15D used in the centrifugal pump according to the third embodiment of the present invention will be described. 17, (A) is a plan view of the rotor 15D, (B) is a front view of the rotor 15D, (C) is a bottom view of the rotor 15D, and (D) is a line HH in FIG. 17 (C). Sectional drawing, (E) is a perspective view of the rotor 15D viewed from the bottom surface side, and (F) is a perspective view of the rotor 15D viewed from the top surface side.

  The illustrated rotor 15D has the same configuration as the rotor 15B shown in FIG. 13 except that the impeller and the bearing are integrated. That is, the rotor 15B shown in FIG. 13 is composed of three parts of the bearing 13, the impeller 150B, and the permanent magnet 155A, whereas the rotor 15D shown in FIG. 17 is an integrated impeller 150D and a permanent magnet. It consists of two parts with 155A.

  The integrated impeller 150D having such a configuration is manufactured by integrally molding a bearing and an impeller, or by cutting after integrally molding a bearing and an impeller. As the material of the integrated impeller 150D, a slidable material having wear resistance and low friction loss is selected. As such a material, for example, a resin material based on nylon or polyphenylene sulfide resin can be used.

  Specifically, in the rotor 15B shown in FIG. 13, the inner cylindrical portion 151 of the impeller 150B is rotatably attached to the bearing 13. Therefore, the rotor 15B is rotatably attached to the fixed shaft 11 (FIGS. 11 and 12) via the bearing 13, and the rotor 15B and the bearing 13 are separate. On the other hand, in the rotor 15D shown in FIG. 17, the inner cylindrical portion 151A of the integrated impeller 150D functions as an axis. Therefore, the rotor 15D is directly rotatably attached to the fixed shaft 11 (FIGS. 11 and 12), and the rotor and the bearing are integrated.

  According to the rotor 15D having such a configuration, it is not necessary to assemble the impeller and the bearing. As a result, there is no sticking error at the time of assembly, and thus a more accurate rotor 15D can be manufactured. Since the dimensional accuracy of the rotor 15D is improved, the amount of eccentricity of the center of gravity of the rotor 15D is reduced. As a result, there are effects such as a reduction in friction loss between the fixed shaft 11 and the bearing (inner cylindrical portion) 151A, a reduction in current consumption, an increase in output (power), a longer life, and a reduction in vibration and noise.

  Further, if the impeller 150A and the bearing 13 are separate, the strength of the joint surface between the impeller 150A and the bearing 13 is weak against the vibration and impact of the centrifugal pump. On the other hand, in the integrated impeller 150D of the rotor 15D according to the present embodiment, since there is no joint surface, higher reliability is realized with respect to vibration and impact of the centrifugal pump.

  Although the present invention has been described above with reference to preferred embodiments, it is needless to say that the present invention is not limited to the above-described embodiments.

It is a disassembled perspective view which shows the external appearance structure of the conventional centrifugal pump. It is sectional drawing about the line II-II of FIG. It is the perspective view which looked at the conventional upper case used for the centrifugal pump shown in FIG. 1 from one direction of the bottom face side. It is the perspective view which looked at the conventional upper case used for the centrifugal pump shown in FIG. 1 from the other direction of the bottom face side. It is sectional drawing about line VV of the upper case used for the centrifugal pump shown in FIG. It is an expanded sectional view of the assembly which combined the upper case and rotor used for the centrifugal pump shown in FIG. It is a disassembled perspective view of the assembly body of the conventional rotor and a bearing. It is sectional drawing of the assembly body of the conventional rotor and a bearing in case an impeller is provided with six blades. It is a figure which shows the conventional rotor comprised by insert-molding a permanent magnet and an impeller, (A) is a top view of a rotor, (B) is a front view of a rotor, (C) is a bottom view of a rotor, (D) is sectional drawing in line BB of FIG.9 (C), (E) is a perspective view of a rotor. It is sectional drawing which shows the principal part of the centrifugal pump provided with the rotor shown in FIG. It is a disassembled perspective view which shows the external appearance structure of the centrifugal pump which concerns on the 1st Embodiment of this invention. It is sectional drawing about the line XII-XII of FIG. It is a figure which shows the rotor used for the centrifugal pump shown by FIG. 11, (A) is a top view of a rotor, (B) is a front view of a rotor, (C) is a bottom view of a rotor, (D) is a figure. Sectional drawing in line FF of 13 (C), (E) is a perspective view of the rotor. It is sectional drawing which shows the principal part of the centrifugal pump provided with the rotor shown in FIG. It is a figure which shows the other rotor used for the centrifugal pump which concerns on the 2nd Embodiment of this invention, (A) is a top view of a rotor, (B) is a front view of a rotor, (C) is a rotor of a rotor FIG. 15D is a bottom view, FIG. 15D is a cross-sectional view taken along line GG in FIG. 15C, and FIG. FIG. 16 is a bottom view of the rotor showing magnetic poles and magnetic pole boundaries of the rotor shown in FIG. 15. It is a figure which shows another rotor used for the centrifugal pump which concerns on the 3rd Embodiment of this invention, (A) is a top view of a rotor, (B) is a front view of a rotor, (C) is a rotor. (D) is a cross-sectional view taken along line H-H in FIG. 17 (C), (E) is a perspective view of the rotor viewed from the bottom surface side, and (F) is a perspective view of the rotor viewed from the top surface side. It is.

Explanation of symbols

10B Centrifugal pump 11 Fixed shaft 13 Bearing 15B, 15C, 15D Rotor 150B, 150C Impeller 150D Integrated impeller 151 Inner cylindrical portion 151A Inner cylindrical portion (bearing)
153 Ring part 154A, 154B Outer cylindrical part 154a Protrusion part 155A, 155B Permanent magnet 155a Flange part (protrusion part)
155b Protruding portion 157 Blade 17 Substrate 19 Stator 21 Lower case 23 Seal rubber 25 Upper case 31 Magnetic detection element 32 Drive element

Claims (14)

In a centrifugal pump provided with a rotor having an impeller rotatably arranged on a fixed shaft extending in the direction of the central axis, and an annular permanent magnet arranged on the inner periphery of the impeller,
The impeller and the permanent magnet are integrally formed by insert molding,
The impeller has an outer cylindrical portion that covers an outer peripheral wall of the permanent magnet, and the permanent magnet has a protruding portion that protrudes radially outward at a lower end of the outer cylindrical portion.   The centrifugal pump according to claim 1, wherein the projecting portion includes a flange portion projecting over the entire circumference at a lower end of the outer cylindrical portion.   The centrifugal pump according to claim 1, wherein a plurality of the protruding portions are arranged at equiangular intervals at a lower end of the outer cylindrical portion.   The centrifugal pump according to claim 3, wherein each of the plurality of protrusions includes a boundary between magnetic poles of the rotor.   The centrifugal pump according to any one of claims 1 to 4, wherein the impeller includes an inner cylindrical portion that is rotatably attached to the fixed shaft via a bearing.   The centrifugal pump according to any one of claims 1 to 4, wherein the impeller includes an integral impeller including an inner cylindrical portion that is directly rotatably attached to the fixed shaft.   The centrifugal pump according to any one of claims 1 to 6, wherein the centrifugal pump includes a magnetic detection element that detects a rotational position of the rotor in a vicinity of a lower end outer periphery of the rotor.   The said centrifugal pump has a casing which accommodates the said rotor, and the stator arrange | positioned on the opposing surface of the said annular | circular shaped permanent magnet through this casing. Centrifugal pump. In a rotor having an impeller rotatably disposed on a fixed shaft extending in the direction of the central axis, and an annular permanent magnet disposed on the inner periphery of the impeller,
The impeller and the permanent magnet are integrally formed by insert molding,
The impeller has an outer cylindrical portion that covers an outer peripheral wall of the permanent magnet, and the permanent magnet has a protruding portion that protrudes radially outward at a lower end of the outer cylindrical portion.   The rotor according to claim 9, wherein the projecting portion includes a flange portion projecting over the entire circumference at a lower end of the outer cylindrical portion.   The rotor according to claim 9, wherein a plurality of the protruding portions are arranged at equiangular intervals at a lower end of the outer cylindrical portion.   The rotor according to claim 11, wherein each of the plurality of protrusions includes a boundary between magnetic poles of the rotor.   The rotor according to any one of claims 9 to 12, wherein the impeller includes an inner cylindrical portion that is rotatably attached to the fixed shaft via a bearing.   The rotor according to any one of claims 9 to 12, wherein the impeller comprises an integral impeller including an inner cylindrical portion that is directly rotatably attached to the fixed shaft.

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