JP2007043821A - Motor and water pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor and a water pump capable of suppressing the occurrence of heat stress of a magnetic circuit thin-wall portion. <P>SOLUTION: This water pump 10 includes a resin member 52 which includes a space C1 between an inside wall of magnetic circuit thin wall 68 and a rotor magnet 48 in the rotating-shaft direction. This structure allows the space C1 to absorb a change in dimensions due to heat expansion of the rotor magnet 48, even if the heat expansion of the rotor magnet 48 occurs by the use of the water pump 10 under a hot circumstance, for instance, in an engine compartment or the like. Consequently, this pressing force is suppressed so as to be low, as long as the magnetic circuit thin wall 68 is not pressed by the rotor magnet 48, or even if the magnetic circuit thin wall 68 is pressed by the rotor magnet 48. Thus, this system can prevent occurrence of heat stress at the magnetic circuit thin wall 68, even when the plate thickness of the magnetic circuit thin wall 68 of a resin member 46 is reduced for motor performance improvement. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor and a water pump, and more particularly to a motor and a water pump including a rotor in which a rotor magnet is accommodated in a resin member.

Conventionally, as a water pump provided with this type of motor, there is the following (for example, see Patent Document 1). For example, in the example described in Patent Document 1, a rotor including a driven magnet on a centrifugal pump is provided. In this rotor, the driven side magnet is covered with a driven side cover member integrally formed with the impeller together with the driven side back plate.
Japanese Patent Laid-Open No. 8-232882

  However, in general, in this type of water pump, the rotor magnet has a larger linear expansion coefficient than the resin member that houses the rotor magnet. For this reason, when the water pump is used in a high temperature environment, the rotor magnet thermally expands and is pressed by the rotor magnet, thereby generating thermal stress in the resin member.

  Here, in order to improve the motor efficiency, it is necessary to reduce the air gap between the rotor and the stator. For this purpose, the resin portion of the resin member on the side facing the stator coil (the magnetic member of the resin member is magnetic). It is necessary to reduce the plate thickness of the stator side resin portion located in the circuit. However, when the plate thickness of the resin portion on the side facing the stator coil in the resin member is reduced in this way, the thermal stress of the resin portion on the side facing the stator coil increases.

  At this time, in order to reduce the thermal stress of the resin portion on the side facing the stator coil, it is conceivable to increase the thickness of the resin portion. However, if this is done, the air gap between the rotor and the stator is increased, so that the amount of effective magnetic flux is reduced, thereby reducing the motor efficiency.

  Moreover, since the permeance coefficient of the rotor magnet is reduced, the rotor magnet is easily demagnetized. Therefore, it is necessary to select a rotor magnet that can maintain the amount of magnetic flux for a long time, and if the same amount of magnetic flux is to be secured, the material cost of the rotor magnet increases.

  This invention is made | formed in view of the said situation, Comprising: The objective is the resin part (stator side resin part located in a magnetic circuit among resin members) of the resin member by the side facing a stator coil among the resin members. An object of the present invention is to provide a motor and a water pump that can suppress the generation of thermal stress in the resin portion facing the stator coil even when the plate thickness is reduced to improve motor efficiency.

  In order to solve the above-mentioned problem, the invention according to claim 1 is provided with a stator provided with a stator coil around a rotating shaft, and a rotor magnet so as to face the stator coil in the rotating shaft direction or the radial direction. And a rotor in which the rotor magnet is housed in a resin member, and the resin member is provided with a gap between the inner wall of the resin portion facing the stator coil and the rotor magnet. It is characterized by.

  As described above, in the first aspect of the present invention, the resin member is provided with a gap between the inner wall of the resin portion facing the stator coil and the rotor magnet. According to this configuration, even if the rotor magnet is thermally expanded by using the motor, for example, in a high temperature environment, the dimensional change due to the thermal expansion of the rotor magnet is absorbed by the gap provided in the resin member.

  Therefore, even if the resin member is not pressed by the rotor magnet or the resin member is pressed by the rotor magnet, the pressing force is kept low. As a result, even if the plate thickness of the resin portion of the resin member facing the stator coil (the resin portion of the resin member on the stator side located in the magnetic circuit) is thinned to improve motor efficiency, this stator coil It is possible to suppress the occurrence of thermal stress in the resin portion on the opposite side.

  At this time, as in the invention described in claim 2, when the gap is set to a dimension that does not interfere with the inner wall of the resin portion facing the rotor magnet and the stator coil even if the rotor magnet is thermally expanded. Even if the rotor magnet is thermally expanded by using the motor in, for example, a high temperature environment, the resin member can be prevented from being pressed by the rotor magnet. Thereby, it can suppress reliably that a thermal stress generate | occur | produces in the resin part of the side facing a stator coil with the thermal expansion of a rotor magnet.

  Further, as in the third aspect of the invention, the rotor is provided with a back yoke on the opposite side of the rotor magnet from the stator, the back yoke is fixedly held by a resin member, and the rotor magnet is fixed to the back yoke. As described above, even if the rotor magnet is accommodated in the resin member by providing a gap between the inner wall of the resin portion of the resin member facing the stator coil and the rotor magnet, the resin member By fixing the rotor magnet to the fixedly held back yoke, displacement of the rotor magnet in the resin member is prevented.

  According to a fourth aspect of the invention, the resin member includes at least a first resin member and a second resin member that are divided into two, and the first resin member holds and holds the back yoke. When the second resin member is configured to be connected and fixed to the first resin member so as to maintain a gap with the rotor magnet, the back yoke is held on the first resin member in order to assemble the rotor. Then, the rotor magnet is fixed to the back yoke and the second resin member is connected and fixed to the first resin member, and the assembly of the rotor is easy.

  In addition, if the first resin member and the second resin member are formed by resin molding, the first resin member and the second resin member can be formed with high accuracy in advance. Of these, the gap between the inner wall of the resin portion facing the stator coil and the rotor magnet can be reliably secured.

  Further, as in the invention described in claim 5, when the resin member has a gap between the back yoke of the rotor magnet and a surface other than the fixed surface, the resin member faces the stator coil. It is also possible to suppress the occurrence of thermal stress in the resin part other than the resin part on the side to be performed (resin part on the stator side located in the magnetic circuit among the resin members).

  In addition, like the invention of Claim 6, the motor as described in any one of Claims 1 thru | or 5 can be used suitably for a water pump.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It should be noted that members, arrangements, and the like described below do not limit the present invention, and it goes without saying that various modifications can be made in accordance with the spirit of the present invention.

[First embodiment]
First, the configuration of the water pump 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  The water pump 10 according to the first embodiment of the present invention is suitably used for, for example, an automobile engine cooling system. The water pump 10 includes a housing 12, an impeller 14, and a motor 16 as main components.

  The housing 12 includes a pump housing 18, a stator housing 20, and an end housing 22. A spiral pump chamber 24 is formed in the pump housing 18, and an impeller 14 in which a plurality of blades 14 </ b> A are radially provided is rotatably accommodated inside the pump chamber 24.

  Further, a fluid suction port 26 for sucking fluid into the pump chamber 24 is provided on the rotation shaft of the pump housing 18, and the fluid in the pump chamber 24 is discharged in the tangential direction of the pump housing 18. A fluid discharge port 28 is provided.

  The stator housing 20 is sandwiched and fixed between the pump housing 18 and the end housing 22. A shaft support 30 is formed on the stator housing 20, and a shaft 32 is fixed to the shaft support 30. A circuit unit 36 is mounted on the end housing 22. This circuit unit 36 supplies a necessary current to a stator coil 44 of the motor 16 described later.

  The impeller 14 includes a plurality of blades 14A and is formed integrally with a rotor 40 of the motor 16 described later. The impeller 14 rotates together with the rotor 40 to apply a centrifugal force radially outward to the fluid in the pump chamber 24 and convey the fluid to the radially outer side of the pump chamber 24.

  The motor 16 of the present embodiment is an axial gap type in which the stator 38 and the rotor 40 are arranged so as to face each other in the rotation axis direction. The stator 38 includes a stator core 42 and a plurality of stator coils 44. The stator core 42 is formed with a plurality of salient poles 42A projecting in the direction of the rotational axis around the rotational axis, and a stator coil 44 is wound around each salient pole 42A.

  The stator 38 is integrated with the stator housing 20 by molding the stator core 42, the plurality of stator coils 44, and a terminal (not shown). Further, the stator 38 has a canned structure covered with a mold resin by being molded.

  The rotor 40 includes a resin member 46, a rotor magnet 48 (made of neodymium), and a back yoke 50 (made of S10C). The resin member 46 includes a first resin member 52 and a second resin member 54 by being divided into two. As shown in FIG. 2, the first resin member 52 has a disk-shaped main body 56 around the rotation axis, and the impeller 14 is integrally formed on the upper surface of the main body 56.

  Further, a housing portion 58 for housing the rotor magnet 48 and the back yoke 50 is provided on the opposite side of the main body portion 56 from the impeller 14. The rotor magnet 48 and the back yoke 50 are disposed around the rotation axis by being accommodated in the accommodating portion 58. At this time, the back yoke 50 is press-fitted and fixed to the inner diameter side of the accommodating portion 58, and the rotor magnet 48 is fixed to the stator 38 side of the back yoke 50 by magnetic attraction.

  The rotor magnet 48 may be fixed to the stator 38 side of the back yoke 50 with an adhesive or the like, or is fixed to the stator 38 side of the back yoke 50 using a mechanical joining member such as a clip (not shown). Also good. Further, the back yoke 50 is not limited to press-fitting but may be fixed to the accommodating portion 58 by snap fitting or the like.

  A projecting portion 64 projecting in the axial direction is provided at the center of the surface of the main body portion 56 opposite to the impeller 14. The protrusion 64 is provided with a hole 66, and the shaft 32 and the bearing 34 are inserted into the hole 66.

  The second resin member 54 is provided with a thin disk-shaped magnetic circuit thin portion 68 so as to face the rotor magnet 48 provided in the main body portion 56 of the first resin member 52 in the rotation axis direction. Further, on the both sides in the radial direction of the magnetic circuit thin portion 68, the upper and lower sides in the rotational axis direction (here, for convenience of explanation, the upper and lower sides are used for convenience, but the orientation of the water pump 10 is arranged in this direction. The first flange portion 70 and the second flange portion 72 are provided so as to project toward the same.

  In the present embodiment, as shown in FIG. 1, the joint surface between the first resin member 52 and the second resin member 54 in a state where the rotor magnet 48 and the back yoke 50 are accommodated in the accommodating portion 58. Are sealed together by welding. Further, by sealing and bonding in this way, the first resin member 52 and the second resin member 54 are connected and fixed, and the rotor magnet 48 and the back yoke 50 are connected to the first resin member 52 and the second resin member 52. The resin member 54 is hermetically sealed.

  Note that the connection and fixing of the first resin member 52 and the second resin member 54 is not limited to the seal bonding by welding as described above, but at the joint between the first resin member 52 and the second resin member 54. A seal member such as an O-ring may be disposed to screw the first resin member 52 and the second resin member 54 together.

  In the present embodiment, when the first resin member 52 and the second resin member 54 are connected and fixed as described above, the thermal stress of the magnetic circuit thin portion 68 is reduced as shown in FIG. Accordingly, a gap C1 is provided in the direction of the rotation axis between the inner wall of the magnetic circuit thin portion 68 (corresponding to the resin portion on the side facing the stator coil 44) and the rotor magnet 48.

  Further, in order to reduce the thermal stress of the side wall portions 60, 62 of the housing portion 58 formed in the first resin member 52, the diameter is also formed between the inner wall of the side wall portions 60, 62 of the housing portion 58 and the rotor magnet 48. Clearances C2 and C3 are provided in the direction, respectively.

  In the present embodiment, the clearance C1 in the rotation axis direction provided between the inner wall of the magnetic circuit thin portion 68 and the rotor magnet 48 is such that the rotor magnet 48 and the magnetic circuit thin portion 68 are not affected by thermal expansion. The dimension that does not interfere with the inner wall is set to 0.1 mm, for example.

  Also, radial gaps C2 and C3 provided between the inner walls of the side wall portions 60 and 62 of the housing portion 58 formed in the first resin member 52 and the rotor magnet 48 are, for example, 0.1 mm each. Is set to In the present embodiment, the thickness of the magnetic circuit thin portion 68 is set to 1 mm.

  By the way, the gap C1 is not only set to such a gap dimension that the magnetic circuit thin portion 68 and the rotor magnet 48 do not completely interfere with each other when the rotor magnet 48 is thermally expanded as described above, but also when the rotor magnet 48 is thermally expanded. The rotor magnet 48 presses the magnetic circuit thin portion 68, but the gap size may be set so that the pressing force can be kept low.

  In the water pump 10 configured as described above, when the impeller 14 rotates as the motor 16 rotates, the fluid is sucked into the pump chamber 24 from the fluid suction port 26, and the sucked fluid is subjected to centrifugal force by the impeller 14. Then, it is conveyed to the radially outer side of the pump chamber 24. Further, the fluid conveyed to the radially outer side of the pump chamber 24 by the centrifugal force by the impeller 14 is conveyed around the rotation axis along the spiral wall surface of the pump chamber 24, and is tangential to the outside from the fluid discharge port 28. It is discharged toward.

  Next, the operation and effect of the water pump 10 according to the first embodiment of the present invention will be described.

  In the water pump 10 according to the first embodiment of the present invention, the resin member 46 is provided with a gap C <b> 1 in the rotation axis direction between the inner wall of the magnetic circuit thin portion 68 and the rotor magnet 48. According to this configuration, even if the rotor magnet 48 is thermally expanded by using the water pump 10 in a high-temperature environment such as an engine room of a vehicle, the dimensional change due to the thermal expansion of the rotor magnet 48 is caused by the gap C1. Absorbed.

  Therefore, even if the magnetic circuit thin portion 68 is not pressed by the rotor magnet 48 or the magnetic circuit thin portion 68 is pressed by the rotor magnet 48, this pressing force is kept low. As a result, even when the plate thickness of the magnetic circuit thin portion 68 of the resin member 46 is reduced in order to improve motor efficiency, it is possible to suppress the occurrence of thermal stress in the magnetic circuit thin portion 68.

  In particular, as in the water pump 10 according to the first embodiment of the present invention, if the gap C1 is set to a dimension that does not interfere with the rotor magnet 48 and the magnetic circuit thin portion 68 even if the rotor magnet 48 is thermally expanded, Even if the rotor magnet 48 is thermally expanded by using the water pump 10 in a high temperature environment such as an engine room of a vehicle, for example, the magnetic circuit thin portion 68 can be prevented from being pressed by the rotor magnet 48. Thereby, it is possible to reliably suppress the occurrence of thermal stress in the magnetic circuit thin portion 68 accompanying the thermal expansion of the rotor magnet 48.

  Further, in the water pump 10 according to the first embodiment of the present invention, the gap C <b> 2 in the radial direction is also formed between the side wall portions 60 and 62 of the housing portion 58 formed in the first resin member 52 and the rotor magnet 48. C3 is provided. Accordingly, it is possible to suppress the occurrence of thermal stress on the side wall portions 60 and 62 of the housing portion 58 in the resin member 46.

  In the water pump 10 according to the first embodiment of the present invention, the rotor 40 is provided with the back yoke 50 on the opposite side of the rotor magnet 48 from the stator 38, and the back yoke 50 is provided in the housing portion 58 of the resin member 46. The rotor magnet 48 is fixed to the back yoke 50 by being pressed and fixed.

  Accordingly, as described above, the gap C1 is provided between the inner wall of the magnetic circuit thin portion 68 and the rotor magnet 48, and the gaps C2 and C3 are provided between the side wall portions 60 and 62 of the housing portion 58 and the rotor magnet 48. Even if the rotor magnet 48 is accommodated in the accommodating portion 58 so as to be provided, the rotor magnet 48 is fixed to the back yoke 50 fixedly held in the accommodating portion 58, so that the rotor magnet 48 is accommodated in the accommodating portion 58. Misalignment is prevented.

  In the water pump 10 according to the first embodiment of the present invention, the resin member 46 includes at least a first resin member 52 and a second resin member 54 that are divided into two parts, and the first resin member 52. However, the back yoke 50 is fixed and held, and the second resin member 54 is connected and fixed to the first resin member 52 so as to maintain the gaps C1, C2, and C3 with the rotor magnet 48.

  Therefore, in order to assemble the rotor 40, the back resin 50 is held by the first resin member 52, the rotor magnet 48 is fixed to the back yoke 50, and the second resin member 54 is attached to the first resin member 52. The rotor 40 can be easily assembled.

  Further, if the first resin member 52 and the second resin member 54 are formed by resin molding, the first resin member 52 and the second resin member 54 can be formed with high accuracy in advance. Accordingly, the gaps C1, C2, and C3 with the rotor magnet 48 can be reliably ensured.

  In the present embodiment, the thermal stress is a stress generated by a difference in dimensional change generated when the temperature rises in a structure composed of a plurality of members having different linear expansion coefficients.

[Second Embodiment]
Next, the configuration of the water pump 80 according to the second embodiment of the present invention will be described with reference to FIGS.

  The water pump 80 according to the second embodiment of the present invention is suitably used for, for example, an automobile engine cooling system. The water pump 80 includes a housing 82, an impeller 84, and a motor 86 as main components.

  The housing 82 includes a pump housing 88, a stator housing 90, an end plate 93, and an end housing 92. The pump housing 88 includes a spiral pump chamber 94, and an impeller 84 in which a plurality of blades 84 </ b> A are radially provided is rotatably accommodated inside the pump chamber 94.

  A fluid suction port 96 for sucking fluid into the pump chamber 94 is provided on the rotation shaft of the pump housing 88, and in order to discharge the fluid in the pump chamber 94 in the tangential direction of the pump housing 88. The fluid discharge port 98 is provided. The pump housing 88 is formed with a shaft support portion 100, and one end of a shaft 102 is fixed to the shaft support portion 100.

  The stator housing 90 is connected and fixed to the pump housing 88, and the stator 108 of the motor 86 is accommodated in the stator accommodating portion 91 formed in the stator housing 90. The end plate 93 is connected and fixed to the end of the wall 97 formed in the stator housing 90 to fix the other end of the shaft 102, and the end housing 92 is connected and fixed to the axial end of the stator housing 90. Has been. A circuit unit 106 is accommodated in a circuit accommodating portion 95 surrounded by the stator housing 90, the end plate 93, and the end housing 92. This circuit unit 106 supplies a necessary current to a stator coil 114 of a motor 86 described later.

  The impeller 84 includes a plurality of blades 84A, and is formed integrally with a rotor 110 of a motor 86 described later. The impeller 84 rotates together with the rotor 110 to apply a centrifugal force radially outward to the fluid in the pump chamber 94 and convey the fluid to the radially outer side of the pump chamber 94.

  The motor 86 of this embodiment is a radial gap type in which the stator 108 and the rotor 110 are arranged so as to face each other in the radial direction. The stator 108 includes a stator core 112 and a plurality of stator coils 114. The stator core 112 is formed with a plurality of salient poles 112A projecting radially inward around the rotation axis, and a stator coil 114 is wound around each salient pole 112A. The stator 108 has a can structure by being isolated from the pump chamber 94 by a wall 97 and an end plate 93 formed in the stator housing 90.

  The rotor 110 includes a resin member 116, a rotor magnet 118 (made of neodymium), and a back yoke 120 (made of S10C). The resin member 116 includes a first resin member 122 and a second resin member 124 by being divided into two. The first resin member 122 has a cylindrical main body 126 around the rotation axis, and an impeller 84 is integrally formed on the upper surface of the main body 126.

  Further, as shown in FIG. 4, a housing portion 128 that houses the rotor magnet 118 and the back yoke 120 is provided on the opposite side of the main body portion 126 from the impeller 84. The rotor magnet 118 and the back yoke 120 are disposed around the rotation axis by being accommodated in the accommodating portion 128. At this time, the back yoke 120 is press-fitted and fixed to the inner diameter side of the accommodating portion 128, and the rotor magnet 118 is fixed to the stator 108 side of the back yoke 120 by magnetic attraction.

  The rotor magnet 118 may be fixed to the stator 108 side of the back yoke 120 with an adhesive or the like, or fixed to the stator 108 side of the back yoke 120 using a mechanical joining member such as a clip (not shown). Also good. Further, the back yoke 120 is not limited to press-fitting but may be fixed to the housing portion 128 by snap fitting or the like.

  And as FIG. 3 shows, the protrusion part 134 which protrudes in an axial direction is provided in the opposite side to the impeller 84 of the main-body part 126. As shown in FIG. The protrusion 134 is provided with a hole 136, and the shaft 102 and the bearing 104 are inserted into the hole 136. Further, as shown in FIG. 4, an engagement recess 123 that can be engaged with the engagement protrusion 125 formed on the second resin member 124 is formed on the radially outer side of the protrusion 134 of the main body 126. Has been. Further, a radially outer side than the engaging convex portion 125 of the second resin member 124 is a flange portion 127.

  In this embodiment, the engagement convex portion 125 of the second resin member 124 is engaged with the engagement concave portion 123 of the first resin member 122 and the first resin member 122 and the second resin member 124 are engaged. The joint portion is properly sealed and joined by welding. Further, by sealing and bonding in this manner, the first resin member 122 and the second resin member 124 are connected and fixed, and the rotor magnet 118 and the back yoke 120 are connected to the first resin member 122 and the second resin member 122. The resin member 124 is hermetically sealed.

  Note that the connection and fixation between the first resin member 122 and the second resin member 124 is not limited to the seal bonding by welding as described above, but at the joint between the first resin member 122 and the second resin member 124. A sealing member such as an O-ring may be disposed to screw the first resin member 122 and the second resin member 124 together.

  In the present embodiment, when the first resin member 122 and the second resin member 124 are connected and fixed as described above, as shown in FIG. 4, the first resin member 122 faces the stator coil 114. In order to reduce the thermal stress of the resin part (hereinafter referred to as the magnetic circuit thin part 138) on the side to be rotated, a gap C4 is provided in the rotation axis direction between the inner wall of the magnetic circuit thin part 138 and the rotor magnet 118.

  In addition, a gap C5 is provided in the rotation axis direction between the inner wall of the side wall 130 of the housing portion 128 formed in the first resin member 122 and the rotor magnet 118, and the rotor magnet 118 and the second resin member 124 are provided. A gap C6 is provided in the direction of the rotation axis between the inner wall of the flange portion 127 formed on the inner surface of the flange portion 127.

  In the present embodiment, the radial gap C4 provided between the inner wall of the magnetic circuit thin portion 138 and the rotor magnet 118 is the inner wall of the rotor magnet 118 and the magnetic circuit thin portion 138 even if the rotor magnet 118 is thermally expanded. As a dimension that does not interfere with, for example, 0.1 mm is set.

  Further, a clearance C5 in the rotation axis direction provided between the inner wall of the side wall 130 of the housing portion 128 formed in the first resin member 122 and the rotor magnet 118, and the second resin member 124 are formed. The gap C6 in the rotation axis direction provided between the inner wall of the flange portion 127 and the rotor magnet 118 is set to 0.1 mm or more (for example, 0.5 mm). In the present embodiment, the plate thickness of the magnetic circuit thin portion 138 is set to 1 mm.

  By the way, the gap C4 is not only set to a gap size so that the magnetic circuit thin portion 138 and the rotor magnet 118 do not completely interfere with each other when the rotor magnet 118 is thermally expanded as described above, but also when the rotor magnet 118 is thermally expanded. Although the rotor magnet 118 presses the magnetic circuit thin portion 138, the gap may be set to such a size that the pressing force can be kept low.

  In the water pump 80 configured as described above, when the impeller 84 rotates as the motor 86 rotates, fluid is sucked into the pump chamber 94 from the fluid suction port 96, and the sucked fluid is subjected to centrifugal force by the impeller 84. Then, it is conveyed to the radially outer side of the pump chamber 94. Further, the fluid conveyed to the radially outer side of the pump chamber 94 by the centrifugal force by the impeller 84 is conveyed around the rotation axis along the spiral wall surface of the pump chamber 94 and tangentially extends from the fluid discharge port 98 to the outside. It is discharged toward.

  Next, the operation and effect of the water pump 80 according to the second embodiment of the present invention will be described.

  In the water pump 80 according to the second embodiment of the present invention, the resin member 116 is provided with a gap C4 in the radial direction between the inner wall of the magnetic circuit thin portion 138 and the rotor magnet 118. According to this configuration, even if the rotor magnet 118 is thermally expanded by using the water pump 80 in a high-temperature environment such as an engine room of a vehicle, the dimensional change due to the thermal expansion of the rotor magnet 118 is caused by the gap C4. Absorbed.

  Therefore, even if the magnetic circuit thin portion 138 is not pressed by the rotor magnet 118 or the magnetic circuit thin portion 138 is pressed by the rotor magnet 118, this pressing force is kept low. As a result, even when the plate thickness of the magnetic circuit thin portion 138 of the resin member 116 is reduced in order to improve motor efficiency, it is possible to suppress the occurrence of thermal stress in the magnetic circuit thin portion 138.

  In particular, as in the water pump 80 according to the second embodiment of the present invention, if the gap C4 is set to a dimension that does not cause interference between the rotor magnet 118 and the magnetic circuit thin portion 138 even if the rotor magnet 118 is thermally expanded, Even when the rotor magnet 118 is thermally expanded by using the water pump 80 in a high temperature environment such as an engine room of a vehicle, the magnetic circuit thin portion 138 can be prevented from being pressed by the rotor magnet 118. Thereby, it is possible to reliably suppress the occurrence of thermal stress in the magnetic circuit thin portion 138 accompanying the thermal expansion of the rotor magnet 118.

  In the water pump 80 according to the second embodiment of the present invention, the clearance C5 is also provided between the inner wall of the side wall portion 130 of the housing portion 128 formed in the first resin member 122 and the rotor magnet 118 in the rotation axis direction. And a gap C6 is provided in the rotational axis direction between the inner wall of the flange portion 127 formed in the second resin member 124. Therefore, it is possible to suppress the occurrence of thermal stress on the side wall 130 of the housing portion 128 formed on the first resin member 122 and the flange portion 127 formed on the second resin member 124.

  In the water pump 80 according to the second embodiment of the present invention, the rotor 110 is provided with a back yoke 120 on the opposite side of the rotor magnet 118 from the stator 108, and the back yoke 120 is provided in the housing portion 128 of the resin member 116. The rotor magnet 118 is fixed to the back yoke 120 by being pressed and fixed.

  Therefore, as described above, the gap C4 is provided between the inner wall of the magnetic circuit thin portion 138 of the resin member 116 and the rotor magnet 118, and the side wall portion 130 of the accommodating portion 128 formed in the first resin member 122 is provided. Even if the rotor magnet 118 is housed in the housing portion 128 so that the gaps C5 and C6 are provided between the inner wall and the rotor magnet 118 and between the inner wall of the flange portion 127 formed in the second resin member 124, respectively. Since the rotor magnet 118 is fixed to the back yoke 120 fixedly held in the housing portion 128, the rotor magnet 118 is prevented from being displaced in the housing portion 128.

  In the water pump 80 according to the second embodiment of the present invention, the resin member 116 includes at least a first resin member 122 and a second resin member 124 that are divided into two parts, and the first resin member 122. However, the back yoke 120 is fixedly held, and the second resin member 124 is connected and fixed to the first resin member 122 so as to maintain the gaps C4, C5, and C6 with the rotor magnet 118.

  Therefore, in order to assemble the rotor 110, the back resin 120 is held by the first resin member 122, the rotor magnet 118 is fixed to the back yoke 120, and the second resin member 124 is attached to the first resin member 122. The rotor 110 can be easily assembled.

  If the first resin member 122 and the second resin member 124 are formed by resin molding, the first resin member 122 and the second resin member 124 can be formed with high accuracy in advance. Accordingly, the gaps C4, C5, and C6 with the rotor magnet 118 can be reliably ensured.

  In the present embodiment, the thermal stress is a stress generated by a difference in dimensional change generated when the temperature rises in a structure composed of a plurality of members having different linear expansion coefficients.

It is sectional drawing which shows the structure of the water pump which concerns on 1st embodiment of this invention. It is a principal part enlarged view of the water pump shown in FIG. It is sectional drawing which shows the structure of the water pump which concerns on 2nd embodiment of this invention. It is a principal part enlarged view of the water pump shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,80 ... Water pump, 12, 82 ... Housing, 14, 84 ... Impeller, 14A, 84A ... Blade, 16, 86 ... Motor, 18, 88 ... Pump housing, 20, 90 ... Stator housing, 22, 92 ... End housing, 24, 94 ... Pump chamber, 26, 96 ... Fluid inlet, 28, 98 ... Fluid outlet, 30, 100 ... Shaft support, 32, 102 ... Shaft, 34, 104 ... Bearing, 36, 106 ... Circuit unit, 38, 108 ... Stator, 40, 110 ... Rotor, 42, 112 ... stator core, 42A, 112A ... salient pole, 44, 114 ... stator coil, 46, 116 ... resin member, 48, 118 ... rotor magnet, 50, 120 Back yoke, 52, 122 ... first resin member, 54, 124 ... second resin member, 56, 126 ... main body, 58, 128 ... housing part, 60, 62, 130 ... Side wall part, 64, 134 ... Projection part, 66, 136 ... Hole part, 68, 138 ... Magnetic circuit thin part, 70 ... First flange part, 72 ... Second flange portion, 91 ... stator accommodating portion, 93 ... end plate, 95 ... circuit accommodating portion, 97 ... wall portion, 123 ... engaging recess, 125 ... engaging Convex part, 127 ... flange part, C1, C2, C3, C4, C5, C6 ... gap

Claims (6)

A stator provided with a stator coil around the rotation axis;
In a motor provided with a rotor magnet provided so as to face the stator coil in the rotational axis direction or radial direction, and the rotor magnet accommodated in a resin member,
The motor, wherein the resin member is provided with a gap between an inner wall of the resin portion facing the stator coil and the rotor magnet.   2. The gap according to claim 1, wherein the gap is set to a size that does not cause interference between the rotor magnet and an inner wall of the resin portion facing the stator coil even when the rotor magnet is thermally expanded. motor. The rotor is provided with a back yoke on the opposite side of the rotor magnet from the stator,
The back yoke is fixedly held by the resin member,
The motor according to claim 1, wherein the rotor magnet is fixed to the back yoke. The resin member includes a first resin member and a second resin member that are divided into at least two parts,
The first resin member fixedly holds the back yoke;
The motor according to claim 3, wherein the second resin member is connected and fixed to the first resin member so as to maintain a gap with the rotor magnet.   5. The motor according to claim 3, wherein the resin member has a gap between a surface of the rotor magnet other than a surface fixed to the back yoke.   A water pump comprising the motor according to any one of claims 1 to 5.

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