Liquid-cooled motor
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SINFONIA TECHNOLOGY CO LTD
- Filing Date
- 2026-01-09
- Publication Date
- 2026-07-30
Smart Images
Figure JP2026000530_30072026_PF_FP_ABST
Abstract
Description
Liquid-cooled motor Cross-reference to related applications
[0001] This application claims priority based on Japanese Patent Application No.2025-010867, which is incorporated herein by reference in its entirety.
[0002] The present invention relates to a liquid-cooled motor that cools a stator with a cooling liquid.
[0003] In recent years, in the electrification of aircraft and automobiles, lightweight and high-output (high output density) drive motors have been demanded. In such motors, the heat generation density of the stator coil becomes high, and the temperature rise of the motor becomes a problem. Therefore, a method of flowing a cooling liquid inside the stator to directly cool the stator coil is used.
[0004] For the cooling method of directly cooling the stator coil, for example, as shown in FIG. 1 of Japanese Patent No. 6603737, a sealing means as a partition wall for separating the stator and the rotor is arranged between the stator and the rotor to construct a sealed space on the stator side.
[0005] By the way, in order to increase the output density of the motor, higher torque and higher efficiency are required. In order to achieve this, the management of the air gap between the stator and the rotor is important. Since this air gap directly affects the performance of the motor, a fiber reinforced plastic (FRP) that can form a non-magnetic and thin-walled cylindrical shape is used for the partition wall.
[0006] Since the cooling liquid circulates in the sealed space, pressure acts on the partition wall for constructing the sealed space on the stator side from the radially outer side toward the radially inner side. Therefore, the partition wall is closely fitted to the stator core in the stator or adhered (fixed) by press fitting. In the coil end portion where the partition wall cannot be adhered to the stator core in the stator core, support means (protrusions) as partition wall support portions are arranged in a portion corresponding to the coil end portion (projecting axially outward from the end face of the stator core). And the support means mechanically supports the partition wall.
[0007] Japanese Patent No. 6603737
[0008] In particular, in the field of electric aircraft, to reduce weight, aluminum alloys are used for the housing that contains the power-generating parts of the motor. When this aluminum alloy is used over a wide temperature range, forces due to forced displacement are generated between it and the stator (specifically the stator core), which is a magnetic material, due to the difference in linear expansion. When these forces are applied to the thin bulkheads and bulkhead supports, there is a risk of deformation or damage to the bulkheads, bulkhead supports, and other components.
[0009] Therefore, the object of the present invention is to provide a liquid-cooled motor that can suppress deformation and damage caused by the dissimilar materials of the housing and stator.
[0010] The liquid-cooled motor of the present invention comprises a housing, a rotor that rotates about an axis relative to the housing, a stator fixed to the housing and generating a magnetic force for the rotation of the rotor, the stator being formed in part from a material having a different coefficient of thermal expansion than the housing, a partition wall provided between the rotor and the stator along the axial direction to partition a flow path for the cooling liquid within the housing, a partition wall support portion provided along the partition wall to support the portion of the partition wall that does not overlap with the stator in the axial direction, the partition wall support portion being composed of multiple members, at least one of the multiple members being made of a different material from the other members, and a buffer portion interposed between the housing and the partition wall support portion, the buffer portion being made from a material having a smaller modulus of elasticity than the housing and the partition wall support portion.
[0011] Furthermore, in the liquid-cooled motor of the present invention, at least two of the plurality of members are combined in a radial direction perpendicular to the direction of the axis, and the first separation member, which is furthest from the partition wall in the radial direction, may have lower conductivity than the first proximity member, which is closest to the partition wall in the radial direction.
[0012] Furthermore, in the liquid-cooled motor of the present invention, at least one of the first proximity member and the first separation member has a higher Young's modulus than the partition wall, and the first separation member may be non-conductive and non-magnetic.
[0013] Furthermore, at least two of the plurality of members are combined in the direction of the axis, and the second proximity member, which is closest to the stator core of the stator, may have weaker magnetism than the second separation member, which is furthest from the stator core.
[0014] Furthermore, the second separating member may have a higher Young's modulus than the second adjacent member.
[0015] Furthermore, the liquid-cooled motor comprises a housing, a rotor that rotates about an axis relative to the housing, a stator fixed to the housing and generating a magnetic force for the rotation of the rotor, the stator being formed in part from a material with a different coefficient of thermal expansion than the housing, a partition wall provided between the rotor and the stator along the axial direction to partition the flow path for the cooling liquid within the housing, a partition wall support portion provided along the partition wall to support the portion of the partition wall that does not overlap with the stator in the axial direction, and a buffer portion interposed between the housing and the partition wall support portion, made from a material with a lower modulus of elasticity than the housing and the partition wall support portion. The partition wall support portion comprises a formed buffer portion, and the partition wall support portion has a first region that is radially separated from the partition wall and axially close to the stator core of the stator, a second region that is radially separated from the partition wall and axially separated from the stator core of the stator more than the first region, a third region that is radially closer to the partition wall more than the first region and axially closer to the stator core of the stator more than the second region, and a fourth region that is radially closer to the partition wall more than the first region and axially separated from the stator core of the stator more than the third region, wherein the first region is formed of a non-magnetic and non-conductive material, and the third region may be formed of a non-magnetic material.
[0016] Figure 1 is a longitudinal cross-sectional view of the liquid-cooled motor of the present invention. Figure 2 is an enlarged view of part II in Figure 1. Figure 3 is a diagram showing a modified example of the partition wall support. Figure 4 is a diagram showing yet another modified example of the partition wall support. Figure 5 is a diagram showing yet another modified example of the partition wall support. Figure 6 is a diagram showing yet another modified example of the partition wall support. Figure 7 is a diagram showing yet another modified example of the partition wall support.
[0017] Hereinafter, several embodiments of the liquid-cooled motor of the present invention (hereinafter sometimes simply referred to as "motor") will be described based on the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and will not be repeated in the description.
[0018] A liquid-cooled motor 1 according to one embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a longitudinal cross-sectional view of the liquid-cooled motor 1 of the present invention. Figure 2 is an enlarged view of portion II in Figure 1.
[0019] As shown in Figure 1, the motor 1 includes a housing 3 for housing the motor unit 2 that generates power. Inside the housing 3, there is a partition wall 4 for creating a space for the flow of cooling liquid. To reduce weight, the housing 3 is made of, for example, aluminum or an aluminum alloy. In Figure 1, the direction along the axis X of the rotating shaft 5, which will be described later, is defined as the axial direction, and the direction perpendicular to the axial direction (up and down in Figure 1) is defined as the radial direction in the following description.
[0020] The housing 3 is equipped with an inlet IN and an outlet OUT for the cooling liquid. The inlet IN is connected to a guide pipe (not shown) that guides the cooling liquid supplied by a pump (not shown) from a tank (not shown) which is an external storage section for storing the cooling liquid, and the outlet OUT is connected to a discharge pipe (not shown) that returns the cooling liquid that has cooled the stator coil 92 (described later) back to the tank. In this embodiment, cooling oil is used as the cooling liquid, but water or various other cooling media may also be used.
[0021] Motor 1 is configured as an inner rotor type, with a rotor 8 (described later) mounted radially inside the stator 9 (described later) so as to rotate integrally with a rotating shaft 5 that is rotatably supported approximately at the center of the housing 3. Motor 1 can be used, for example, as an electric motor for aircraft or automobiles, as a drive source for actuators such as robots, as a drive source for pumps or compressors, as a flywheel energy storage device, or for other purposes.
[0022] As shown in Figure 1, the housing 3 comprises a cylindrical housing body 31 and a pair of lids 32 and 33 that close the openings at both axial ends of the housing body 31. An inlet IN for the cooling liquid is formed at one of the axial ends of the housing body 31 (the upper and right side in Figure 1), and an outlet OUT for the cooling liquid is formed at the other axial end of the housing body 31 (the upper and left side in Figure 1). The cooling liquid from the inlet IN enters the annular inlet-side space K1 formed by the partition support 11, the lids 33, the housing body 31, the stator core 91, the stator coil 92, and the buffer 12, and then enters the right end of a plurality of slots (not shown) formed on the inner circumference of the stator core 91. The cooling liquid then passes between the plurality of slots in the left-right direction, that is, it passes in the left-right direction of the stator core 91, cooling the stator coil 92, which will be described later. The cooling liquid, having passed through multiple channels formed by multiple slots and partition walls 4, is discharged from the left end of each of the multiple slots into an annular outlet-side space K2 formed by the partition wall support 11, lid 32, housing body 31, stator core 91, stator coil 92, and buffer 12, and then discharged to outlet OUT which communicates with outlet-side space K2. However, the flow of the cooling liquid is not limited to this.
[0023] A pair of through holes 31A and 31B are formed in the radial center of the pair of covers 32 and 33, through which the rotating shaft 5 passes in the axial direction. A pair of left and right bearings 6 and 7 are fitted into the through holes 31A and 31B to serve as bearings that rotatably support the rotating shaft 5 that passes through the through holes 31A and 31B. In addition, a pair of annular flange portions 31C and 31D are formed on the pair of covers 32 and 33, projecting inward in the axial direction and positioned opposite each other in the axial direction.
[0024] The motor unit 2 includes a rotor 8 that is fitted onto a rotating shaft 5 so as to be integrally rotatable with respect to the housing 3 so as to rotate about axis X, and a stator 9 that is positioned between the partition wall 4 and the housing body 31. In other words, the stator 9 is located radially outward from the rotor 8. The rotor 8 is provided with a plurality of permanent magnets (not shown) along its circumference. In this embodiment, a permanent magnet type rotor is used, but any type of rotor, such as a wound-type rotor or an induction motor's squirrel-cage type rotor, may be used.
[0025] The stator 9 generates a magnetic force to rotate the rotor 8 and comprises a stator core 91 that forms multiple magnetic poles, a stator coil 92 mounted on the stator core 91, and an insulating member (not shown) that insulates the stator core 91 and the stator coil 92. The stator core 91 is made of a laminate of electromagnetic steel sheets made of iron, which is a different material (metal) from the housing 3. In other words, the stator 9 is made of a material with a different coefficient of thermal expansion than the housing 3. In this embodiment, the stator core 91 is made of a laminate of electromagnetic steel sheets, but it can also be made of materials such as silicon steel sheets, permendur (cobalt steel), or permalloy.
[0026] The partition wall 4 is made of glass fiber reinforced plastic (GFRP), which is non-magnetic and can form a thin-walled cylindrical shape. Glass fiber reinforced plastic (GFRP) has a low coefficient of thermal expansion among plastics. The axial length of the partition wall 4 is longer than the axial length (shaft length) of the stator core 91. More specifically, the partition wall 4 is configured to protrude axially outward more than the axial outer end of the stator coil 92 which protrudes axially outward from the stator core 91. Furthermore, the partition wall 4 is fixed to the entire inner surface 91A of the stator core 91 with adhesive 10. This ensures the rigidity of the partition wall 4. As shown in Figure 2, a gap S1 is formed between the axial outer end 4A of the partition wall 4 and the inner surface 3A of the housing 3 facing it.
[0027] A pair of partition wall support parts 11, 11 are provided along the partition wall 4 to support the portion of the partition wall 4 that does not overlap with the stator core 91 in the axial direction, that is, the pair of end portions 4T, 4T that protrude outward in the axial direction from both ends of the stator core 91. Each partition wall support part 11 extends outward from the axial outer end of the stator core 91 to the position of the axial outer end 4A of the partition wall 4. The position of the axial outer end 4A of the partition wall 4 may be axially inward from the axial outer end of the partition wall support part 11. At a minimum, the partition wall 4 only needs to be able to fix the partition wall support parts 11 so that they do not shift position, and the outer circumferential surface of the partition wall 4 should have a region that overlaps with the inner circumferential surface of the partition wall support part 11 in the axial direction. Therefore, the axially inward end of the partition wall support part 11 may be spaced apart from the axial outer end of the stator core 91.
[0028] Each partition support portion 11 is a cylindrical member formed separately from the partition wall 4 and is fixed to the radially outer surface of the partition wall 4 by adhesive 10. By bonding the partition support portions 11, 11 to the partition wall 4 in this way, the partition wall 4 is mechanically supported. It is preferable that the partition support portions 11 are made of the same material as the stator core 91 (iron in this embodiment) or a material having a similar coefficient of linear expansion. As a result, the deformation amounts of the stator core 91 and the partition support portions 11, which are the amount of contraction or expansion that changes due to the ambient environment and temperature changes of the motor, become equal, and these two members deform together, so that the radial deformation amount of the partition wall 4 becomes equal over its entire surface, making it difficult for cracks to occur in the partition wall 4.
[0029] Furthermore, it is preferable to use a non-magnetic material for the partition wall support portion 11 that is less susceptible to electromagnetic interference from the stator 9. This reduces leakage flux compared to the case where a magnetic material is used, thereby reducing eddy current losses in the partition wall support portion 11. Moreover, it is preferable that the material of the partition wall support portion 11 be both non-magnetic and non-conductive. This prevents eddy currents from flowing in the partition wall support portion 11. Therefore, no eddy current losses occur in the partition wall support portion 11 during motor operation. In addition, dielectric breakdown due to contact between the partition wall support portion 11 and the stator coil 92 is less likely to occur, so the distance between the partition wall support portion 11 and the coil end portion (the part of the coil that protrudes axially outward from both axial ends of the stator core 91) can be reduced, making it easier to miniaturize and lighten the motor 1. Examples of non-magnetic materials include stainless steel, aluminum, and titanium. Examples of non-magnetic and non-conductive materials include ceramic materials, but zirconia material with a coefficient of thermal expansion close to that of the stator core 91 is preferred. As shown in Figure 2, the partition support 11 includes, for example, a first member 111 and a second member 112. The first member 111 corresponds to, for example, a "first proximity member" or a "second proximity member." The second member 112 corresponds to, for example, a "first separation member" or a "second separation member."
[0030] The first member 111 is the part of the partition support 11 that positions and holds the second member 112. Specifically, the first member 111 is a cylindrical member that extends from the axial end of the stator core 91 to the axial outer end 4A of the partition 4. The first member 111 is configured in an L-shape, with an L-shaped notch 111K formed in a longitudinal cross-sectional view where the second member 112 fits into the axial outer end.
[0031] As the material for the first member 111 is geographically close to the stator core 91, it is preferable to use a non-magnetic material that is less susceptible to electromagnetic influence from the stator core 91 and stator coil 92. This reduces leakage flux compared to the case where a magnetic material is used, thereby reducing eddy current losses in the first member 111. Furthermore, it is preferable that the material of the first member 111 be both non-magnetic and non-conductive. This prevents eddy currents from flowing in the first member 111. Therefore, no eddy current losses occur in the first member 111 during motor operation. In addition, dielectric breakdown due to contact between the first member 111 and the stator coil 92 is less likely to occur, so the distance between the first member 111 and the coil end portion (the part of the coil that protrudes axially outward from both axial ends of the stator core 91) can be reduced, making it easier to miniaturize and lighten the motor 1. Examples of non-magnetic materials include stainless steel, aluminum, and titanium. Examples of non-magnetic and non-conductive materials include ceramic materials, but zirconia material with a coefficient of thermal expansion close to that of the stator core 91 may also be used. Furthermore, like the partition wall 4, it may also be made of glass fiber reinforced plastic (GFRP).
[0032] The second member 112 holds the buffer portion 12. In this embodiment, the buffer portion 12 is an O-ring. The second member 112 is an annular member located axially and radially outward of the partition wall support portion 11. The second member 112 has a groove portion 112M capable of housing the buffer portion 12. The groove portion 112M is located in the axial middle portion of the second member 112 and radially outward. When the buffer portion 12 is housed in the groove portion 112M, the top of the buffer portion 12 protrudes slightly from the groove portion 112M in the radial direction of the second member 112. The second member 112 is fixed to the notch 111K of the first member 111 with adhesive. Note that the first member 111 and the second member 112 may be integrated by means other than adhesive, such as fitting.
[0033] The material for the second member 112 can be any material that has sufficient strength to withstand the elastic restoring force generated when the O-ring, which is the buffer portion 12, is crushed by the pressing force from the housing 3. However, if good machinability for accurately forming the groove portion 112M and strength are required, a metal material is preferable. Alternatively, a ceramic material may also be used. When using this metal material, constructing the partition support portion 11 from multiple members rather than manufacturing the partition support portion 11 as a single structure leads to improved productivity and cost reduction. Furthermore, when constructing the partition support portion 11 from multiple members, using metal material in part improves processing accuracy, making it easier to obtain the required precision.
[0034] As shown in Figure 2, a buffer portion 12 is interposed between the radial outer surface 112A at the axial outer end of each bulkhead support portion 11 and the radial inner surface 31d of the flange portion 31D of the housing 3 which is radially opposite to it. This buffer portion 12 is provided to mitigate the force generated on the bulkhead 4 and bulkhead support portion 11 due to forced displacement caused by the difference in linear expansion between the housing 3 and the stator core 91 when temperature changes occur. In order to provide this buffer portion 12, a gap S2 is formed between the radial outer surface 112A and the radial inner surface 31d.
[0035] The buffer portion 12 is made of a material with a lower modulus of elasticity than the housing 3 and the bulkhead support portion 11. Specifically, the buffer portion 12 is made of a highly versatile rubber O-ring that has elasticity around its entire circumference in the circumferential direction relative to the bulkhead support portion 11. Therefore, the buffer portion 12 can not only mitigate (reduce) the force generated on the bulkhead 4 and the bulkhead support portion 11 due to forced displacement caused by the difference in linear expansion between the housing 3 and the stator core 91, but also function as a sealing member that seals the gap S2 between the flange portion 31C or 31D and the bulkhead support portion 11 or 11. In addition, the buffer portion 12 also has the function of absorbing the change in gap dimensions caused by the difference in linear expansion between the housing 3 and the stator core 91 and maintaining airtightness. By mitigating (reduce) the aforementioned force, damage (cracking) to the bulkhead 4 and the bulkhead support portion 11 and peeling of the adhesive 10 between the bulkhead 4 and the stator core 91 can be suppressed. Furthermore, sealing the space between the housing 3 (flange portion 31C or 31D) and the bulkhead support portion 11 with an O-ring improves ease of assembly and disassembly. In addition, maintenance against oil leakage from the sealing portion between the housing 3 (flange portion 31C or 31D) and the bulkhead support portion 11 is improved by changing or replacing the O-ring through reassembly or by installing a new oil drain port.
[0036] Furthermore, by placing an O-ring as a sealing member on the radially outer side of the partition wall 4, a sealing member is not required on the radially inner side of the partition wall 4. Therefore, only the partition wall 4 aligned with the axial direction exists on the radially inner side of the partition wall 4. This makes the radially inner side of the partition wall 4 flat, so even if oil leaks from the partition wall 4 to the radially inner side, the oil will travel along the flat radially inner surface of the partition wall 4. For example, the leaked oil can be discharged to the outside of the housing 3 simply by forming a discharge port in the housing 3. This simplifies the mechanism for discharging the leaked oil to the outside of the housing 3. Also, by discharging the leaked oil to the outside of the housing 3, it becomes less likely for the leaked oil to accumulate in the air gap between the rotor 8 and the partition wall 4. This reduces the frictional force on the rotor 8 during rotation caused by the leaked oil. Furthermore, it prevents the motor 1 from burning out due to heat generated by friction with the leaked oil during the rotation of the rotor 8. Furthermore, by positioning the O-ring at the radially outer end of the partition wall 4, if the housing 3 is provided with a transparent section (not shown) radially inward from the radially inner surface 31d of the flange portion 31D, the condition of the seal boundary of the O-ring pressing against the flange portion 31C or 31D can be easily visually inspected from the transparent section. This allows for the rapid detection of oil leaks from the seal boundary, leading to improved productivity and early detection of malfunctions.
[0037] The buffer portion 12 is fitted into an annular groove portion 112M formed so as to be recessed radially inward at the axial outer end of the radial outer surface of each partition wall support portion 11, with a portion of it protruding radially outward from the groove portion 112M. By using an O-ring with an inner diameter smaller than the inner diameter of the groove portion 112M as the buffer portion 12, the O-ring can be set in the groove portion 112M while taut, making it difficult for the O-ring to come off the groove portion 112M. Therefore, the O-ring can be prevented from falling out during assembly.
[0038] With the above configuration, the partition support section 11 is composed of multiple members, and at least one of the multiple members is made of a different material from the other members. Therefore, a material with performance suitable for the function required for each part can be used, and the performance of the members can be satisfied. In other words, the buffer section 12 can be placed between the housing 3 and the partition support section 11 while satisfying the performance requirements, so the force caused by the housing 3 and the stator 9 being made of different materials can be mitigated by the buffer section 12. Consequently, deformation and damage caused by the housing 3 and the stator 9 being made of different materials can be suppressed.
[0039] Next, a modified example of the partition wall support 11 will be described with reference to Figures 3 to 7. Figures 3 to 7 show partition wall support 11A to partition wall support 11E, which are modified examples of the partition wall support 11. Each of the partition wall support 11A to partition wall support 11E is composed of two (or more than three) members. As shown in Figure 3, the partition wall support 11A has, for example, a first member 113 and a second member 114. The first member 113 corresponds to, for example, a "first proximity member" or a "second separation member". The second member 114 also corresponds to, for example, a "first separation member" or a "second proximity member". Note that parts that are not described are the same as those in Figure 2, and are therefore given the same reference numerals and their description is omitted.
[0040] The first member 113 is the part of the partition support portion 11A that positions and holds the second member 114. Specifically, the first member 113 is an annular member located axially outward and radially inward of the partition support portion 11A. Since the first member 113 is separated radially and axially from the stator core 91 and coil end portion, it is less susceptible to the influence of magnetic flux. Therefore, there are no particular restrictions on material selection, and a material with a high Young's modulus, ferromagnetism, and high conductivity can be applied to the second member 114. This ensures the support rigidity of the first member 113 with respect to the partition 4, and as a result, the rigidity of the partition 4 can be increased.
[0041] The second member 114 holds the buffer portion 12. The second member 114 is a cylindrical member extending from the axial end of the stator core 91 to the axial outer end 4A of the partition wall 4. The second member 114 is configured in an L-shape, with an L-shaped notch 114K formed in a longitudinal cross-sectional view where the first member 113 fits into the axial outer end. When the first member 113 is fitted into the second member 114, the radial inner surface of the first member 113 and the radial inner surface of the second member 114 are flush in the radial direction. The second member 114 has a groove portion 114M capable of housing the buffer portion 12. The groove portion 114M is located on the axial outer and radial outer sides of the second member 114.
[0042] Next, another modified example of the partition support 11 will be described based on Figure 4. As shown in Figure 4, the partition support 11B includes, for example, a first member 115 and a second member 116. The first member 115 corresponds to, for example, a "first separation member" or a "second proximity member." The second member 116 also corresponds to, for example, a "first proximity member" or a "second separation member."
[0043] The first member 115 is a part of the partition support portion 11B that positions and holds the second member 116. Specifically, the first member 115 is an annular member located axially inward and radially outward of the partition support portion 11B. The first member 115 is close to the stator core 91 and the coil end portion. The first member 115 is made of, for example, an insulating synthetic resin material. This ensures the insulating performance of the coil end portion. Because the first member 115 is close to the stator core 91 and the coil end portion, the influence of magnetic flux can be avoided even in locations that are susceptible to magnetic flux.
[0044] The second member 116 holds the buffer portion 12. The second member 116 is a cylindrical member extending from the axial end of the stator core 91 to the axial outer end 4A of the partition wall 4. The second member 116 is configured in an L shape with an L-shaped notch 116K formed in a longitudinal sectional view where the first member 115 enters the inner axial end portion. The second member 116 has a groove portion 116M capable of accommodating the buffer portion 12. The groove portion 116M is located on the outer side in the axial direction and the outer side in the radial direction of the second member 116. The second member 116 is made of, for example, a non-magnetic metal material. Thereby, the cylindrical strength of the partition wall support portion 11B can be improved, and the positioning accuracy of the sealing position is improved.
[0045] Next, another modified example of the partition wall support portion 11 will be described based on FIG. 5. As shown in FIG. 5, the partition wall support portion 11C has, for example, a first member 117 and a second member 118. The first member 117 corresponds to, for example, "the first proximity member" or "the second proximity member". Also, the second member 118 corresponds to, for example, "the first separation member" or "the second separation member".
[0046] The first member 117 is a portion that positions and holds the second member 118 in the partition wall support portion 11C. Specifically, the first member 117 is an annular member located on the inner side in the axial direction and the inner side in the radial direction of the partition wall support portion 11C. Since the first member 117 is close to the stator core 91, it is easily affected by magnetic flux. Therefore, the first member 117 is made of, for example, a non-magnetic synthetic resin material.
[0047] The second member 118 holds the buffer portion 12. The second member 118 is a cylindrical member that extends from the axial end of the stator core 91 to the axial outer end 4A of the partition wall 4. The second member 118 is configured in an L-shape in a longitudinal sectional view in which the first member 117 enters the axial inner end portion, and an L-shaped notch 118K is formed. In a state where the first member 117 enters the second member 118, the radially inner surface of the first member 117 and the radially inner surface of the second member 118 are flush in the radial direction. The second member 118 has a groove portion 118M capable of accommodating the buffer portion 12. The groove portion 118M is located on the axial outer side and the radial outer side of the second member 118. The second member 118 is made of, for example, a non-magnetic metal material. Thereby, the cylindrical strength of the partition wall support portion 11C can be improved, and the positioning accuracy of the sealing position can be improved. Note that since the second member 118 is close to the coil end portion, it is preferably made of a non-conductive material.
[0048] Next, another modified example of the partition wall support portion 11 will be described based on FIG. 6. As shown in FIG. 6, the partition wall support portion 11D has, for example, a first member 119 and a second member 120. The first member 119 and the second member 120 are combined in the radial direction.
[0049] The first member 119 is a portion that positions and holds the second member 120 in the partition wall support portion 11D and is a portion that contacts the partition wall 4. Specifically, the first member 119 is a cylindrical member that extends from the axial end of the stator core 91 to the axial outer end 4A of the partition wall 4. Although the first member 119 is separated from the coil end portion in the axial direction, since it is close to the stator core 91, it is easily affected by the magnetic field. By making the first member 119 a non-magnetic metal material, for example, a material having a higher Young's modulus than the partition wall 4 can be applied to the first member 119, so that the liquid-cooled motor 1 can be downsized. The first member 119 corresponds to, for example, the "first proximity member".
[0050] The second member 120 holds the buffer portion 12. The second member 120 is a cylindrical member extending from the axial end of the stator core 91 to the axial outer end 4A of the partition wall 4. The second member 120 has a groove portion 120M capable of housing the buffer portion 12. The groove portion 120M is located on the axial outer and radial outer sides of the second member 120.
[0051] Furthermore, the conductivity of the second member 120 is lower than that of the first member 119. This allows the second member 120 to have lower conductivity than the first member 119, thereby improving insulation reliability and reducing eddy current losses. In addition, the second member 120 is non-conductive and non-magnetic. Examples of non-magnetic materials include stainless steel, aluminum, and titanium. Examples of non-magnetic and non-conductive materials include ceramic materials, but other options include zirconia materials with a coefficient of thermal expansion close to that of the stator core 91. Because the second member 120 is non-conductive and non-magnetic, leakage flux can be reduced while ensuring insulation reliability. Furthermore, if a material with a higher Young's modulus than the partition wall 4 is applied to the second member 120, for example, the liquid-cooled motor 1 can be miniaturized. The second member 120 corresponds to, for example, the "first separation member".
[0052] Next, another modified example of the partition support 11 will be described based on Figure 7. As shown in Figure 7, the partition support 11E includes, for example, a first member 121 and a second member 122. The first member 121 and the second member 122 are combined in the axial direction.
[0053] The first member 121 is a part of the partition wall support 11E that positions and holds the second member 122, and contacts the partition wall 4. Specifically, the first member 121 is a cylindrical member that extends from the axial end of the stator core 91 to an intermediate position between the axial outer end 4A of the partition wall 4. The first member 121 has weaker magnetism than the second member 122. Therefore, because the first member 121 has weaker magnetism than the second member 122, its magnetic resistance is greater, which reduces magnetic flux leakage and thus reduces eddy current loss. Furthermore, it is preferable that the material of the first member 121 is non-magnetic and non-conductive. This prevents eddy currents from flowing. Therefore, no eddy current loss occurs in the first member 121 during motor operation. The first member 121 corresponds to, for example, the "second proximity member".
[0054] The second member 122 holds the buffer portion 12. The second member 122 is in contact with the partition wall 4. Specifically, the second member 122 is a cylindrical member connected to the axial outer end of the first member 121 and extending from the axial outer end of the first member 121 to the axial outer end 4A of the partition wall 4. The second member 122 has a groove portion 122M capable of housing the buffer portion 12. The groove portion 122M is located in the axial middle portion of the second member 122 and radially outward. Furthermore, the second member 122 has a higher Young's modulus than the first member 121. Because the second member 122 has a higher Young's modulus than the first member 121, it can have higher rigidity compared to a configuration where the partition wall support portion 11E is made up of the first member 121 alone. In other words, the rigidity of the partition wall 4 and the partition wall support portion 11E can be increased, thus reducing the deflection of the partition wall 4 and the partition wall support portion 11E. In other words, the support rigidity on the open end side is increased, which suppresses the deflection of the entire structure, including the bulkhead support section 11E. The second member 122 corresponds to, for example, a "second separation member".
[0055] Embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention. The drawings sometimes schematically show the components in order to facilitate understanding. The number of each component shown in the drawings may differ from the actual number due to the convenience of drawing creation. Furthermore, the components shown in the above embodiments are examples and are not particularly limiting, and various modifications are possible without substantially departing from the effects of the present invention.
[0056] In this embodiment, an inner rotor type motor is used, but an outer rotor type motor may also be used. In the case of an outer rotor type motor, the inner and outer relationship of the rotor and stator in the radial direction is reversed compared to the above embodiment.
[0057] Furthermore, in this embodiment, by configuring the buffer portion 12 with an O-ring, it is possible to mitigate the force generated on the partition wall 4 and partition wall support portion 11 due to forced displacement caused by the difference in linear expansion between the housing 3 and the stator core 91, as well as to function as a sealing member that seals the gap S2 between the flange portion 31C or 31D and the partition wall support portion 11 or partition wall support portion 11. However, it is also possible to implement this by providing two separate members: a force-relieving member that mitigates the force generated on the partition wall 4 and partition wall support portion 11 due to forced displacement caused by the difference in linear expansion between the housing 3 and the stator core 91, and a sealing member that seals the gap S2 between the flange portion 31C or 31D and the partition wall support portion 11 or partition wall support portion 11. If the sealing member is not used, the force-relieving member can also be provided intermittently in the circumferential direction.
[0058] Furthermore, in this embodiment, the cushioning portion 12 is configured to mitigate force radially, but it may also be configured to mitigate force axially.
[0059] Furthermore, in this embodiment, the partition wall 4 and the partition wall support parts 11, 11 are constructed from separate components. However, by integrally forming the partition wall 4 and the partition wall support parts 11, 11, the number of components can be reduced. In this case, by making the coil end portion of the partition wall 4 protrude outwards or inwards, the thickness of the coil end portion of the partition wall 4 is made thicker than other parts. This increases the rigidity of the partition wall 4 itself, allowing the partition wall 4 to maintain a perfect circular shape on its own, thus improving ease of assembly.
[0060] Furthermore, although the partition support portion 11 is configured in a cylindrical shape in this embodiment, the partition support portion 11 may have any shape as long as it can be positioned between the partition 4 and the coil end portion.
[0061] Furthermore, although the housing 3 is made of a single metal material in this embodiment, the portion of the housing 3 that is positioned in such a positional relationship with respect to the stator core 91 that a force due to the difference in linear expansion may be generated, i.e., the flange portion 31C or 31D, and a portion of the housing 3 including the flange portion 31C or 31D, may be made of a material with a different coefficient of linear expansion from the material constituting the stator core 91, and the other portion of the housing 3 may be made of a different material, or in some cases, a synthetic resin. Also, although the stator core 91 is made of a single metal material, the portion of the housing 3 that is positioned in such a positional relationship with respect to the housing 3 that a force due to the difference in linear expansion may be generated, i.e., both axial ends of the stator core 91 may be made of a material with a different coefficient of linear expansion from the material constituting the housing 3, and the other portion of the stator core 91, excluding both axial ends, may be made of a different material.
[0062] Furthermore, although the partition support section 11 is composed of two members in this embodiment, it can also be composed of three members, or any number of members (four or more). By composing the partition support section 11 from multiple members in this way, it is possible to create a partition support section 11 using materials suitable for the required function, depending on its relationship with other components in the motor. Specifically, since each member can be composed of the optimal material according to the magnitude of the force generated on each member, the force generated on each member can be effectively mitigated.
[0063] When the partition support portion 11 is divided into a first region that is separated from the partition 4 and close to the stator core 91, a second region that is separated from the partition 4 and separate from the stator core 91, a third region that is close to the partition 4 and close to the stator core 91, and a fourth region that is close to the partition 4 and separated from the stator core 91, it is preferable to assign the following materials: First region: non-magnetic, non-conductive material Second region: magnetic, conductivity is not a concern Third region: non-magnetic material Fourth region: magnetic, conductivity is not a concern Furthermore, when each region is combined to form one part, it is preferable that the priority of material selection is equal between the material of the second region and the material of the fourth region, with the priority of the material of the third region being higher than that of the material of the second region, and the priority of the material of the first region being higher than that of the material of the third region.
[0064] The material forming the first region is preferably, for example, a ceramic material or a zirconia material. The material forming the third region is preferably, for example, stainless steel, aluminum, or titanium. The materials forming the second and fourth regions are, for example, materials that are dense, easy to maintain airtightness, have high smoothness and workability, and have a high Young's modulus, although magnetism and conductivity are not required. For example, metallic materials (aluminum, iron, stainless steel, titanium, magnesium) or dense ceramics are preferred. Furthermore, these regions do not necessarily need to be separated, and may be composites formed by combining each of these materials.
[0065] The configuration and operation of the above embodiment are summarized below. Of the embodiments described above, the liquid-cooled motor 1 according to the first embodiment comprises a housing 3, a rotor 8 that rotates about an axis X relative to the housing 3, a stator 9 fixed to the housing 3 and generating a magnetic force for the rotation of the rotor 8, the stator 9 being formed in part from a material with a different coefficient of thermal expansion than the housing 3, a partition wall 4 provided between the rotor 8 and the stator 9 along the direction of the axis X to partition a flow path for the cooling liquid within the housing 3, a partition wall support portion 11 provided along the partition wall 4 to support the portion of the partition wall 4 that does not overlap with the stator 9 in the direction of the axis X, the partition wall support portion 11 being composed of multiple members, at least one of the multiple members being made of a different material from the other members, and a buffer portion 12 interposed between the housing 3 and the partition wall support portion 11, the buffer portion 12 being made from a material with a smaller modulus of elasticity than the housing 3 and the partition wall support portion 11.
[0066] According to the first embodiment, the bulkhead support section 11 can use materials with performance suitable for each part for the required function, thereby satisfying the function of the bulkhead support section 11. Furthermore, since the buffer section 12 is placed between the housing 3 and the bulkhead support section 11, the buffer section can mitigate forces and accommodate displacements caused by the housing 3 and stator 9 being made of different materials. Therefore, deformation and damage caused by the housing 3 and stator 9 being made of different materials can be suppressed.
[0067] Furthermore, in the liquid-cooled motor 1 according to the second embodiment based on the first embodiment, at least two of the plurality of members are combined in a radial direction perpendicular to the direction of the axis X (see Figure 6), and the first separating member 120, which is furthest from the partition wall 4 in the radial direction, may have lower conductivity than the first proximity member 119, which is closest to the partition wall 4 in the radial direction.
[0068] According to the second embodiment, since the first separating member 120 has lower conductivity than the first proximity member 119, the first separating member 120 can be made less conductive than the first proximity member 119. In other words, since the first separating member 120 can be made less conductive than the first proximity member 119, insulation reliability can be improved and eddy current losses can be reduced.
[0069] Furthermore, in the liquid-cooled motor 1 according to the third embodiment based on the second embodiment, at least one of the first proximity member 119 and the first separation member 120 has a higher Young's modulus than the partition wall 4, and the first separation member 120 may be non-conductive and non-magnetic.
[0070] According to the third embodiment, since at least one of the first proximity member 119 and the first separation member 120 has a higher Young's modulus than the partition wall 4, the liquid-cooled motor 1 can be miniaturized. Furthermore, since the first separation member 120 is non-conductive and non-magnetic, leakage flux can be reduced.
[0071] Furthermore, in the liquid-cooled motor 1 according to the fourth embodiment based on the first embodiment, at least two of the plurality of members are combined in the direction of the axis X (see Figure 7), and the second proximity member 121, which is closest to the stator core 91 of the stator 9, may have weaker magnetism than the second separation member 122, which is furthest from the stator core.
[0072] According to the fourth embodiment, the second proximity member 121 has weaker magnetism than the second separation member 122, resulting in greater magnetic resistance and reduced magnetic flux leakage. In other words, because the magnetic resistance is increased and magnetic flux leakage is reduced, eddy current losses can be reduced.
[0073] Furthermore, in the liquid-cooled motor 1 according to the fifth embodiment based on the fourth embodiment, the second separation member 122 may have a higher Young's modulus than the second proximity member 121.
[0074] According to the fifth embodiment, the second separation member 113 has a higher Young's modulus than the second proximity member 114, thus increasing its rigidity compared to the case where the partition support 11 is composed solely of the second proximity member 114. In other words, the rigidity of the partition wall 4 and the partition support 11 can be increased, thereby reducing the deflection of the partition wall 4 and the partition support 11.
[0075] Furthermore, the liquid-cooled motor 1 according to the sixth embodiment comprises a housing 3, a rotor 8 that rotates about an axis X relative to the housing 3, a stator 9 fixed to the housing 3 and generating a magnetic force for the rotation of the rotor 8, the stator 9 being formed in part from a material with a different coefficient of thermal expansion than the housing 3, a partition wall 4 provided between the rotor 8 and the stator 9 along the direction of the axis X to partition a flow path for the cooling liquid within the housing 3, a partition wall support portion 11 provided along the partition wall 4 to support the portion of the partition wall 4 that does not overlap with the stator 9 in the direction of the axis X, and a buffer portion 12 interposed between the housing 3 and the partition wall support portion 11, which is more elastic than the housing 3 and the partition wall support portion 11. The partition wall support portion 11 comprises a buffer portion 12 formed from a material with a low coefficient of gravity, and the partition wall support portion 11 has a first region that is radially separated from the partition wall 4 and axially close to the stator core 91 of the stator 9, a second region that is radially separated from the partition wall 4 and axially separated from the stator core 91 of the stator 9 than the first region, a third region that is radially closer to the partition wall 4 than the first region and axially closer to the stator core 91 of the stator 9 than the second region, and a fourth region that is radially closer to the partition wall than the first region and axially separated from the stator core 91 of the stator 9 than the third region, the first region being formed from a non-magnetic and non-conductive material, and the third region being formed from a non-magnetic material.
[0076] According to the sixth embodiment, deformation and damage caused by the housing 3 and stator 9 being made of different materials can be suppressed while satisfying the performance requirements of the components for each part.
[0077] As described above, according to the above embodiment, it is possible to provide a liquid-cooled motor 1 that can suppress deformation and damage caused by the housing 3 and stator 9 being made of different materials.
[0078] 1...(liquid-cooled) motor, 3...housing, 4...bulkhead, 8...rotor, 9...stator, 11, 11A-11E...bulkhead support section, 12...cushion section, 111...first member, 112...second member, 113...first member, 114...second member, 115...first member, 116...second member, 117...first member, 118...second member, 119...first member, 120...second member, 121...first member, 122...second member, X...axis
Claims
1. A liquid-cooled motor comprising: a housing; a rotor that rotates about an axis relative to the housing; a stator fixed to the housing and generating a magnetic force for the rotation of the rotor, the stator being formed in part from a material having a different coefficient of thermal expansion than the housing; a partition wall provided between the rotor and the stator along the axial direction to partition a flow path for a cooling liquid within the housing; a partition wall support portion provided along the partition wall to support the portion of the partition wall that does not overlap with the stator in the axial direction, the partition wall support portion being composed of multiple members, at least one of the multiple members being made of a different material than the other members; and a buffer portion interposed between the housing and the partition wall support portion, the buffer portion being formed from a material having a smaller modulus of elasticity than the housing and the partition wall support portion.
2. The liquid-cooled motor according to claim 1, wherein at least two of the plurality of members are combined in a radial direction perpendicular to the direction of the axis, and the first separation member, which is the furthest from the partition wall in the radial direction, has lower conductivity than the first proximity member, which is the closest to the partition wall in the radial direction.
3. The liquid-cooled motor according to claim 2, wherein at least one of the first proximity member and the first separation member has a higher Young's modulus than the partition wall, and the first separation member is non-conductive and non-magnetic.
4. The liquid-cooled motor according to claim 1, wherein at least two of the plurality of members are combined in the direction of the axis, and the second proximity member, which is closest to the stator core of the stator, has weaker magnetism than the second separation member, which is furthest from the stator core.
5. The liquid-cooled motor according to claim 4, wherein the second separating member has a higher Young's modulus than the second proximity member.
6. The apparatus comprises: a housing; a rotor that rotates about an axis relative to the housing; a stator fixed to the housing and generating a magnetic force for the rotation of the rotor, at least a portion of which is made of a material with a different coefficient of thermal expansion than the housing; a partition wall provided between the rotor and the stator along the direction of the axis to partition a passage through which a cooling liquid passes within the housing; a partition wall support portion provided along the partition wall to support the portion of the partition wall that does not overlap with the stator in the direction of the axis; and a buffer portion interposed between the housing and the partition wall support portion, which is made of a material with a smaller modulus of elasticity than the housing and the partition wall support portion, wherein the partition wall support portion comprises: a first region that is radially separated from the partition wall and axially close to the stator core of the stator; and a second region that is radially separated from the partition wall and axially separated from the stator core of the stator more axially than the first region. A liquid-cooled motor having: a third region that is radially closer to the partition wall than the first region and axially closer to the stator core of the stator than the second region; and a fourth region that is radially closer to the partition wall than the first region and axially further away from the stator core of the stator than the third region, wherein the first region is formed of a non-magnetic and non-conductive material, and the third region is formed of a non-magnetic material.