Motor

Abstract

A motor (1) is provided with: a shaft (40); cylinders (5a, 5b) that are rotatably supported by the shaft (40); an impeller (20) fixed to the cylinders (5a, 5b); a rotor (30) fixed to the impeller (20); a stator (90) surrounding the rotor (30); a space (91) between the shaft (40) and the cylinders (5a, 5b); and a space (92) between the rotor (30) and the stator (90). The spaces (91, 92) are spaces into which a liquid enters, a plurality of first grooves (59) are formed in at least either the inner surface (54) of the cylinders (5a, 5b) or the outer surface (32) of the shaft (40), and a plurality of second grooves (69) are formed in at least either the inner surface (63) of the stator (90) or the outer surface (32) of the rotor (30).

Description

Technical Field

[0001] The present invention relates to electric machines. Background Art

[0002] In motors used in water pumps and the like that use impellers to circulate liquid, a technique is known to form dynamic pressure grooves in bearings to obtain a dynamic pressure effect generated by the circulating liquid. For example, a technique is known to provide lubrication grooves on the end face or inner diameter face of a sliding bearing.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-52709 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In a water pump using a bearing having dynamic pressure grooves, the liquid may flow in a direction away from the impeller through the grooves formed on the inner diameter surface of the bearing. In this case, the circulation of the liquid may be hindered.

[0008] An object of one aspect of the present invention is to provide a motor that can improve the circulation efficiency of liquid.

[0009] Solutions for solving problems

[0010] In one embodiment, the motor comprises: a shaft; a cylinder rotatably supported on the shaft; an impeller fixed to the cylinder; a rotor fixed to the impeller; a stator surrounding the rotor; a space between the shaft and the cylinder; and a space between the rotor and the stator. The space is a space for liquid to enter. A plurality of first grooves are formed on at least one of the inner surface of the cylinder and the outer surface of the shaft, and a plurality of second grooves are formed on at least one of the inner surface of the stator and the outer surface of the rotor.

[0011] According to one aspect, the circulation efficiency of the liquid can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a perspective view showing an example of the water pump in the embodiment.

[0013] Figure 2 It is a top view showing an example of the water pump in the embodiment.

[0014] Figure 3 It is an exploded perspective view showing an example of the water pump in the embodiment.

[0015] Figure 4It is a cross-sectional perspective view showing an example of the water pump in the embodiment.

[0016] Figure 5 It is a perspective view showing an example of the cover in the embodiment.

[0017] Figure 6 It is a perspective view showing an example of a bearing in the embodiment.

[0018] Figure 7 This is another cross-sectional view showing an example of the water pump in the embodiment.

[0019] Figure 8 This is an enlarged cross-sectional view showing an example of the flow of liquid in the embodiment.

[0020] Fig. 9 It is a diagram showing an example of a side cross section and an end surface of a bearing in a first modified example.

[0021] Fig.10 It is a perspective view showing an example of a bearing and a shaft in a second modification.

[0022] Fig.11 It is a perspective view showing an example of a bearing and a shaft in a third modified example.

[0023] Fig.12 It is a perspective view showing an example of a rotor in a fourth modification.

[0024] Fig.13 It is a perspective view showing an example of a cover in a fifth modification. DETAILED DESCRIPTION

[0025] Hereinafter, a water pump as an example of an embodiment of the motor disclosed in the present application will be described in detail based on the accompanying drawings. It should be noted that the dimensional relationship of the elements in the accompanying drawings, the proportion of the elements, etc. may sometimes be different from the actual ones. Sometimes the drawings may include parts with different dimensional relationships and proportions. In each of the drawings, in order to facilitate understanding of the description, a coordinate system is sometimes illustrated with the extension direction of the suction port 11 described later as the positive direction of the Y axis and the extension direction of the discharge port 12 as the positive direction of the X axis.

[0026] [Implementation Method]

[0027] First, use Figures 1 to 3 The water pump 1 in this embodiment will be described. Figure 1 It is a perspective view showing an example of the water pump in the embodiment. Figure 2 It is a top view showing an example of the water pump in the embodiment. Figure 3 FIG. 1 is an exploded perspective view showing an example of a water pump. Figures 1 to 3As shown, the water pump 1 in this embodiment includes a housing 10, an impeller 20, a rotor magnet 30, a shaft 40, bearings 5a and 5b, an O-ring 16, and a stator 90. The stator 90 includes a stator core 70, a coil 80, and a cover 60. It should be noted that, in the following description, when the bearing 5a and the bearing 5b are not distinguished, they may be simply described as the bearing 50.

[0028] The housing 10 is formed of resin or the like, and is disposed on the positive Y-axis direction side of the water pump 1. The housing 10 includes a suction port 11 for sucking liquid (not shown) into the water pump 1, and a discharge port 12 for discharging the liquid in the water pump 1. The liquid is, for example, a known coolant such as propylene glycol.

[0029] like Figure 4 As shown, the housing 10 is watertightly fixed to the cover 60 via an O-ring 16 in the Y-axis direction, thereby constituting the outer shell of the water pump 1 . Figure 4 It is a cross-sectional perspective view showing an example of the water pump in the embodiment. Figure 4 Shown in Figure 2 The water pump 1 is cut along the line AA shown in FIG. The O-ring 16 is a substantially annular member formed of a resin having elasticity such as rubber.

[0030] The cover 60 is, for example, a resin member having a cup-shaped portion that opens toward the positive direction of the Y axis. Figure 5 As shown, the cover 60 in this embodiment includes an inner wall 63 , a bottom 65 , and an outer wall 68 . Figure 5 1 is a perspective view showing an example of a cover in the embodiment. It should be noted that the inner wall 63 of the cover 60 is an example of the inner surface of the stator.

[0031] The bottom 65 constitutes the bottom surface of the cup-shaped portion. A through hole 64 is formed in the bottom 65 for the shaft 40 to be inserted and fixed. It should be noted that in order to improve the water tightness of the internal space, a recessed portion supporting the shaft 40 from the negative direction side of the Y axis may be formed instead of the through hole 64.

[0032] like Figure 5 As shown in FIG. 1 , a dynamic pressure groove 69 is formed on the inner wall 63 of the cover 60. Figure 3 Dynamic pressure grooves 69 are formed between outer circumferential surface 32 of rotor magnet 30 and inner wall 63 of cover 60 of stator 90. It should be noted that outer circumferential surface 32 of rotor magnet 30 is an example of the outer surface of the rotor, and dynamic pressure grooves 69 are an example of second grooves.

[0033] The stator core 70 extends along the Y-axis direction with the shaft 40 as the center, and has a cylindrical shape that surrounds the inner wall 63 of the cover 60. The stator core 70 has a magnetic component (an example of a magnetic body). The magnetic component is formed of a plate-shaped metal component such as a soft magnetic steel plate such as a silicon steel plate or an electromagnetic steel plate. For example, the stator core 70 is formed by stacking a plurality of such plate-shaped metal components in the direction of the rotation axis. It should be noted that, as Figure 4 As shown, the stator core 70 is located, for example, between the inner wall 63 and the outer wall 68 of the housing 60 in the radial direction.

[0034] like Figure 3 and Figure 4 As shown, the stator core 70 includes a yoke 71 and a plurality of teeth 72. The teeth 72 extend radially inward from the inner circumference of the yoke 71. The teeth 72 have protrusions 73 extending in both circumferential directions at the inner diameter side ends thereof.

[0035] The coil 80 is formed, for example, by winding a conductive wire around the teeth 72. In addition, the coil 80 may be a structure in which a wound bobbin coil is fitted into the teeth 72.

[0036] A magnetic gap is formed between the plurality of teeth 72 and the rotor magnet 30. That is, the stator core 70 forms a magnetic field for rotating the rotor magnet 30 by sequentially passing an AC current supplied from the outside through the coil 80 wound around each tooth 72. Thus, the rotor magnet 30 rotates with the shaft 40 as the rotation axis by the magnetic field generated by the stator core 70.

[0037] The impeller 20 rotates in conjunction with the rotor magnet 30, thereby sucking liquid from the suction port 11 and discharging the liquid from the discharge port 12. In the embodiment, the pressure of the impeller 20 rotating in conjunction with the rotor magnet 30 sucks liquid such as coolant from the suction port 11 and discharges the liquid from the discharge port 12. Figure 4 As shown, the rotor magnet 30 and the impeller 20 accommodated in the cover 60 are immersed in the liquid flowing in the water pump 1. On the other hand, the inner wall 63 of the cover 60 prevents the liquid from contacting the stator core 70 and the coil 80.

[0038] The impeller 20 includes a plurality of blades 21 and a rotor core 22. In the impeller 20 of the present embodiment, the blades 21 and the rotor core 22 are integrally formed of resin or the like, but the present invention is not limited thereto and the rotor core 22 may be fixed to the blades 21 formed separately.

[0039] The rotor magnet 30 is fixed to the radially outer side of the rotor core 22 of the impeller 20. The rotor magnet 30 is preferably a rare earth magnet such as a neodymium magnet having high magnetic properties. The rotor core 22 and the rotor magnet 30 constitute a rotor. It should be noted that the rotor magnet 30 may be formed integrally with the rotor core 22, for example.

[0040] like Figure 4 As shown, the inner peripheral surface 25 of the impeller 20 is fixed to the bearing 5a and the bearing 5b. It should be noted that the bearing 5a and the bearing 5b are examples of a cylinder rotatably supported by the shaft.

[0041] The bearing 50 is rotatably supported by the fixed shaft 40. The bearing 50 rotates relative to the shaft 40 in conjunction with the rotating impeller 20.

[0042] like Figure 6 As shown, the bearing 50 includes a pair of end surfaces 51 and 52 in the axial direction, an outer peripheral surface 53 fixed to the inner peripheral surface 25 of the impeller 20 , and an inner surface 54 facing the shaft 40 in the radial direction. Figure 6 It is a perspective view showing an example of a bearing in the embodiment.

[0043] like Figure 6 As shown, a plurality of dynamic pressure grooves 59 are formed on the inner surface 54 of the bearing 50. For example, Figure 6 As shown, the dynamic pressure groove 59 extends between the two end surfaces 51 and 52 along the axial direction and has a shape bent with respect to the axial direction. It should be noted that the dynamic pressure groove 59 is an example of a first groove.

[0044] use Figure 4 , Figure 7 as well as Figure 8 The flow of the liquid flowing in from the suction port 11 and discharged from the discharge port 12 in this structure will be described. Figure 7 This is another cross-sectional view showing an example of the water pump in the embodiment. Figure 8 This is an enlarged cross-sectional view showing an example of the flow of liquid in the embodiment. Figure 7 Shown in Figure 2 The cross section shown is obtained by cutting the water pump 1 along the line BB. Figure 8 Yes Figure 4 This is an enlarged view of the portion shown in box F1.

[0045] The liquid sucked into the water pump 1 from the suction port 11 is as follows Figure 4 As shown by the arrows, the pressure of the rotating impeller 20 spreads radially outward, while a portion of the liquid is Figure 8 As shown, the liquid flows into the first space 91 between the bearing 50 and the shaft 40. Thus, the bearing 5a and the bearing 5b formed with the dynamic pressure groove 59 and the shaft 40 form a fluid bearing by the liquid flowing into the first space 91. It should be noted that the first space 91 is an example of a space between the shaft and the cylinder.

[0046] In this case, the liquid flowing into the first space 91 passes through the dynamic pressure groove 59 formed in the bearing 50. Figure 8 As shown by the arrow, the fluid flows toward the negative direction of the Y axis and flows into the space 66 between the impeller 20, the rotor magnet 30, and the bottom 65 of the cover 60. At this time, the direction of the dynamic pressure groove 59 is consistent with the rotation direction of the impeller 20.

[0047] Then, the liquid flowing into the space 66 passes through the dynamic pressure grooves 69 formed on the inner wall 63 of the cover 60. Figure 7 and Figure 8 As shown by the arrow, it is pulled up to the second space 92 between the cover 60 and the rotor magnet 30. Figure 7 and Figure 8 As shown by the arrow, the air is discharged radially outward by the pressure of the rotating impeller 20. It should be noted that the second space 92 is an example of a space between the rotor and the stator.

[0048] It is difficult to generate dynamic pressure in the space 66, and the inflowing liquid is easily retained. In the embodiment, the retained liquid is easy to flow to the positive direction side of the Y axis through the dynamic pressure groove 69. In this case, by forming the dynamic pressure groove 69 in the cover 60 with a large diameter, a higher dynamic pressure can be obtained, so the amount of liquid sucked from the space 66 to the second space 92 can be increased.

[0049] In addition, the dynamic pressure groove 59 formed in the bearing 50 and the dynamic pressure groove 69 formed in the cover 60 are bent in different directions in the circumferential direction, for example. As a result, the dynamic pressure groove 59 sucks the liquid to the negative direction side of the Y axis, and the dynamic pressure groove 69 draws the liquid upward to the positive direction side of the Y axis as the impeller 20 rotates in one direction.

[0050] As described above, the motor 1 in this embodiment includes: the shaft 40; the cylinders 5a and 5b rotatably supported by the shaft 40; the impeller 20 fixed to the cylinders 5a and 5b; the rotor 30 fixed to the impeller 20; the stator 90 surrounding the rotor 30; the space 91 between the shaft 40 and the cylinders 5a and 5b; and the space 92 between the rotor 30 and the stator 90. The spaces 91 and 92 are spaces for liquid to enter. A plurality of first grooves 59 are formed on at least one of the inner surfaces 54 of the cylinders 5a and 5b or the outer surface 45 of the shaft 40, and a plurality of second grooves 69 are formed on at least one of the inner surface 63 of the stator 90 or the outer surface 32 of the rotor 30. According to this structure, the liquid flowing into the space 66 via the bearing 50 and the shaft 40 constituting the fluid bearing passes through the second grooves 69 without being retained in the space 66, and is easily drawn upward to the positive direction side of the Y axis via the space 92, thereby improving the circulation efficiency of the liquid.

[0051] [Modifications]

[0052] The structure of the present embodiment has been described above, but the embodiment is not limited thereto. For example, the shape of the bearing is not limited to the shape of the embodiment. In addition, the first groove and the second groove may also be formed at other positions. Fig. 9 It is a diagram showing an example of a side section and an end surface of a bearing in a first modification. It should be noted that in the following embodiments and modifications, the same reference numerals are given to the same parts as those shown in the drawings described above, and repeated descriptions are omitted.

[0053] like Fig. 9 As shown in FIG. 1 , in the bearing 150 of the first modified example, a dynamic pressure groove 155 is also formed on the end surface 151 on the positive direction side of the Y axis. Similarly, a dynamic pressure groove 156 is also formed on the end surface 152 on the negative direction side of the Y axis. That is, a plurality of grooves 155 and 156 are formed on the end surfaces 51 and 52 of the bearing 150, respectively. Fig. 9 As shown, the plurality of dynamic pressure generating grooves 155 and 156 may be formed so that their directions are the same.

[0054] In addition, if Fig. 9 As shown in FIG. 1 , on the inner surface 154 of the bearing 150, the dynamic pressure groove 157 is formed only on a portion on the positive direction side of the Y axis, and the dynamic pressure groove 158 is formed only on a portion on the negative direction side of the Y axis. That is, the inner surface 154 of the bearing 150 also has a portion 154p where no dynamic pressure groove is formed. It should be noted that, it may also be, as Fig. 9 As shown, the outer peripheral surface 153 further includes a portion 153p whose size in the radial direction changes. In addition, the axial dimensions of the ranges in which the plurality of dynamic pressure generating grooves 157 and 158 are formed may be different from each other.

[0055] Furthermore, part or all of the dynamic pressure generating grooves may be formed in the shaft instead of in the bearing. Fig.10 FIG. 2 is a perspective view showing an example of a bearing and a shaft in the second modified example. Fig.10 As shown, in the second modified example, the outer surface 245 of the shaft 240 is formed with a bent dynamic pressure groove 249 at a position where the bearing 250 is disposed. In this case, the inner surface 254 of the bearing 250 is not formed with a dynamic pressure groove.

[0056] Furthermore, the dynamic pressure groove is not limited to a bent shape as long as a dynamic pressure effect can be obtained, and may be in other shapes such as a substantially straight line shape or an arc shape. Fig.11 FIG. 1 is a perspective view showing an example of a bearing and a shaft in a third modified example. Fig.11 As shown in FIG. 1 , the inner surface 354b of the bearing 35b in the third modification is formed with a substantially linear dynamic pressure groove 358b. In this case, the inner surface 354b of the bearing 35b includes a portion 354p where the dynamic pressure groove 358b is not formed.

[0057] In addition, you can Fig.11 As shown, dynamic pressure grooves are formed on both the bearing 350 and the shaft 340. Fig.11 The outer surface 345 of the shaft 340 shown in the figure has a substantially linear dynamic pressure groove 347b formed at a position where the bearing 35b is arranged. In this case, the dynamic pressure groove in the shaft 340 is not formed at a position 348b that is radially opposed to the dynamic pressure groove 358b of the bearing 35b.

[0058] In this structure, the dynamic pressure groove 358b formed in the bearing 350 and the dynamic pressure groove 347b formed in the shaft 340 generate a dynamic pressure effect as an integrally bent dynamic pressure groove.

[0059] It should be noted that, in the embodiment, the bearing 5a and the bearing 5b are described as having the same shape, but they may have different shapes. The same applies to the bearings 150, 250, and 350 in each modification.

[0060] In addition, the dynamic pressure grooves formed between the outer surface of the rotor and the inner surface of the stator can also be formed as long as the magnetic flux from the rotor magnet to the stator coil can be ensured. Fig.12 The shown one is formed on the outer surface of the rotor magnet. Fig.12 FIG. 1 is a perspective view showing an example of a rotor in a fourth modified example. Fig.12 In the example shown, a plurality of bent dynamic pressure generating grooves 39 are formed on the outer peripheral surface 432 of the rotor magnet 430. It should be noted that the outer peripheral surface 432 of the rotor magnet 430 is an example of the outer surface of the rotor.

[0061] In addition, the dynamic pressure grooves in the cover can also be Fig.13 Shown is formed on the bottom of the inner side. Fig.13 1 is a perspective view showing an example of a cover in the fifth modification. Fig.13 As shown, in the cover 560 of the fourth modified example, in addition to the dynamic pressure groove 69 formed in the inner wall 63, a dynamic pressure groove 567 is formed in the inner bottom 565. Thus, power can also be obtained in the bottom 565 of the space 66.

[0062] Furthermore, as long as the dynamic pressure effect can be obtained, the bearing 50 may include a protrusion-like shape protruding from the inner surface 54 instead of the dynamic pressure groove 59. The same applies to the other dynamic pressure grooves.

[0063] Although the embodiments and variations of the present invention applied to a water pump are described, the present invention is not limited thereto and can be applied to machines for pumping or conveying liquids or gases and can be used for pumps including water pumps. In other words, the present invention can also be used as a pump motor.

[0064] The present invention has been described above based on the embodiments and various modifications, but the present invention is not limited to the embodiments and various modifications, and various changes can be made without departing from the scope of the present invention. It can be known by those skilled in the art from the description of the claims that the solutions obtained by making various changes without departing from the scope of the present invention are also included in the technical scope of the present invention.

[0065] Description of Reference Numerals

[0066] 1: water pump; 10: housing; 11: suction port; 12: discharge port; 16: O-ring; 20: impeller; 21: blades; 22: rotor core; 25: inner circumference; 30, 430: rotor magnet; 32, 432: outer circumference; 39: dynamic pressure groove; 40, 240, 340: shaft; 45, 245, 345: outer surface; 249, 347b: dynamic pressure groove; 50 (5a, 5b), 150, 250, 350 (35b): bearing; 51, 5 2, 151, 152: end face; 53, 153: outer peripheral surface; 54, 154, 254, 354 (354b): inner surface; 59, 155, 156, 157, 158, 358b: dynamic pressure groove; 60, 560: cover; 63: inner wall; 64: through hole; 65, 565: bottom; 68: outer wall; 69, 567: dynamic pressure groove; 70: stator core; 71: yoke; 72: teeth; 73: protrusion; 80: coil; 90: stator.

Claims

1. A motor having: axis; a cylinder rotatably supported on the shaft; an impeller fixed to the cylinder; A rotor fixed to the impeller; a stator surrounding the rotor; a space between the shaft and the barrel; as well as The space between the rotor and the stator, The space is a space for liquid to enter. A plurality of first grooves are formed on at least one of the inner surface of the cylinder and the outer surface of the shaft. A plurality of second grooves are formed on at least one of an inner surface of the stator and an outer surface of the rotor.

2. The motor according to claim 1, wherein: A fluid bearing is formed by the cylinder and the shaft, Dynamic pressure grooves are formed between an outer surface of the rotor and an inner surface of the stator.

3. The motor according to claim 1, wherein: The stator comprises: a stator core; a plurality of coils wound around the stator core; and a cover covering the stator core. The cover includes an inner peripheral surface facing the rotor in a radial direction, and the plurality of second grooves are formed in the inner peripheral surface.

4. The motor according to claim 1, wherein: A plurality of grooves are formed on the end surface of the cylinder.

5. The motor according to claim 1, wherein: The first groove and the second groove are bent in different directions in the circumferential direction.

Images