Stator and motor

Abstract

To provide a stator which uses aluminum as a coil material and is excellent in motor property, economic efficiency, and resource recyclability.SOLUTION: A stator includes a stator core laminating magnetic steel sheets and a coil wound around the stator core. The coil is composed of an aluminum alloy containing Al: 99.6% or more and Cu: between 0.001% and 0.15% in mass %. In the stator, integrated magnetic flux density IB(500) of the magnetic steel sheet is 90000 TA / m or more and an integrated magnetic flux density IB(5) is 550 TA / m or more. Here, the integrated magnetic flux density IB(500) refers to an integrated value of the magnetic flux density (T) whose intensity H of a magnetic field is between 0 A / m and 50000 A / m. The integrated magnetic flux density IB(5) refers to an integrated value of the magnetic flux density (T) in a zone where intensity H of the magnetic field is between 0 A / m and 500 A / m.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a stator and a motor. [Background technology]

[0002] In recent years, electrification has progressed in the automotive sector to reduce CO2 emissions, and it is predicted that electrification will continue to increase in the future. Here, the motors that provide the driving force are required to be highly efficient in order to reduce the energy consumption used. Furthermore, miniaturization of motors is also required in order to make them easier to install in automobiles.

[0003] To effectively utilize metal resources, the copper winding material and the iron-based electromagnetic steel sheets are separated from used motor cores and reused in products. However, to improve motor performance, the windings must be wound around the motor core with a high space factor. Completely separating the high-space factor windings from the motor core and recycling them requires significant effort and cost. In some cases, the windings are molded with resin, which makes it difficult to separate the iron and copper, leading to copper contamination. Furthermore, the widespread use of electric vehicles as described above is tightening the supply and demand for copper. Not only is the unit price of copper rapidly increasing, but resource depletion is also a concern. Therefore, to reduce motor costs and utilize other resources, a switch from copper to aluminum as the winding material is being considered.

[0004] Aluminum has an electrical resistivity approximately 1.6 times that of copper, so simply replacing copper with aluminum as the winding material increases copper loss by approximately 1.6 times, resulting in a decrease in motor efficiency. Against this background, Patent Document 1 proposes a technology to reduce copper loss by using permanent magnets containing rare earth elements such as dysprosium and having a residual magnetic flux density of 1.32 T to 1.39 T. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6692896 specification Summary of the Invention [Problem to be solved by the invention]

[0006] However, using permanent magnets containing rare earth elements such as dysprosium increases costs, and this undermines the cost reduction effect achieved by changing the winding material to aluminum.

[0007] Furthermore, from the perspective of resource recyclability, aluminum has a lower cost per weight than copper, and the cost of separating and recovering aluminum from used motors is not worth the material value.

[0008] As described above, when aluminum is used as the winding material, it is difficult to achieve both good motor characteristics, economic efficiency, and resource recycling.

[0009] The present disclosure has been made in view of the above circumstances, and aims to provide a stator that uses aluminum as the winding material and has excellent motor characteristics, economy, and resource recyclability. [Means for solving the problem]

[0010] The inventors have conducted extensive research to achieve the above object, and as a result have made the following discoveries, which led to the present invention.

[0011] ·Al: A winding made of an aluminum alloy of 99.6% or more; By using a stator core made of electromagnetic steel sheets with an integral magnetic flux density IB(500) of 90,000 (TA / m) or more and an integral magnetic flux density IB(5) of 550 (TA / m) or more, the stator core and winding material can be effectively recycled as scrap iron without separating them, and excellent motor characteristics can be achieved.

[0012] The present disclosure has been made based on the above findings. That is, the gist of the present disclosure is as follows.

[0013] [1] A stator core made of laminated electromagnetic steel sheets; a winding wound around the stator core; Equipped with the winding is made of an aluminum alloy containing, by mass%, 99.6% or more of Al and 0.001% or more and 0.15% or less of Cu, The stator, wherein the electromagnetic steel sheet has an integrated magnetic flux density IB(500) of 90,000 TA / m or more and an integrated magnetic flux density IB(5) of 550 TA / m or more. Here, the integrated magnetic flux density IB(500) refers to the integral value of the magnetic flux density (T) in the range of the magnetic field strength H from 0 A / m to 50,000 A / m, The integrated magnetic flux density IB(5) indicates the integral value of the magnetic flux density (T) in the range where the magnetic field strength H is 0 A / m to 500 A / m.

[0014] [2] The stator according to [1], wherein the ratio D / h of the stacking height h of the stator core to the outer diameter D is 1.0≦D / h≦3.0.

[0015] [3] The slot space factor of the winding is 60% or more, Iron loss W when an external stress of 10 MPa is applied in a direction perpendicular to the magnetic flux of the electromagnetic steel sheet 10 / 400 (W / kg) is the iron loss W under 0 MPa external stress 10 / 400 (W / kg) or less.

[0016] [4] The stator according to any one of [1] to [3] above, wherein the layers of the electromagnetic steel sheets are bonded together at an area ratio of 85% or more.

[0017] [5] The electromagnetic steel sheet has a punched shear surface, a corner of the electromagnetic steel sheet that comes into contact with the winding is on the punched shear surface side, The stator according to any one of [1] to [4], wherein the stator does not include insulating paper.

[0018] [6] The stator according to any one of [1] to [5], wherein the electromagnetic steel sheet contains, by mass %, Cu: 0.001% or more and 1.0% or less. [7] A motor having the stator according to any one of [1] to [6]. [Effects of the Invention]

[0019] According to the present disclosure, a stator can be provided that uses aluminum as the winding material and has excellent motor characteristics, economy, and resource recyclability. [Brief explanation of the drawings]

[0020] [Figure 1] 10 is a diagram for explaining a measurement example of a DC BH curve and a method for determining an integrated magnetic flux density IB. FIG. [Figure 2] FIG. 1 is a diagram showing an example of measurement of DC BH curves for a plurality of electrical steel sheets. [Figure 3] FIG. 2 is a diagram schematically illustrating the configuration of a test motor. [Figure 4] 10 is a diagram for explaining the positional relationship between a winding and a punched shear surface of an electromagnetic steel sheet. FIG. [Figure 5] 4 is a graph showing the relationship between integral magnetic flux density and torque in Example 1. [Figure 6] 10 is a graph showing the relationship between D / h and torque in an example of the invention according to the second embodiment. [Figure 7] 10 is a graph showing the relationship between the ratio of iron loss (W10 / 400) when a stress of 10 MPa is applied to iron loss (W10 / 400) when no stress is applied and the change in motor efficiency in Example 3. [Figure 8] 10 is a graph showing the relationship between the adhesion area ratio (%) and the changes in motor noise (dB) and motor efficiency in Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present disclosure will be described. Note that the present invention is not limited to the following embodiments. In the following description, "%" representing the content of a component element means "% by mass" unless otherwise specified. Furthermore, in this specification, a numerical range expressed using "to" means a range that includes the numerical values written before and after "to" as the lower and upper limits.

[0022] The stator includes a stator core made of laminated electromagnetic steel sheets and a winding wound around the stator core. As shown in Fig. 3, in one example, a stator core 10 includes a circular or cylindrical back yoke 11 and teeth 13 that are spaced apart from each other in the circumferential direction on the inner peripheral surface of the back yoke 11 and define slots 12 therebetween. The teeth 13 are wound with a winding.

[0023] [Winding] First, the windings wound around the stator core will be described.

[0024] Al: 99.6% or more aluminum alloy The windings are made of an aluminum alloy with an Al content of 99.6% or more. The high Al content of the windings reduces the resistance of the windings and reduces copper loss (aluminum loss). Of the losses in a motor, copper loss (aluminum loss) is generally expressed by the following formula (1): P Cu =RI 2 =ρL / S×I 2 ...Formula (1) where R (Ω): winding resistance, I (Arms): motor current, ρ (Ω m): resistivity of winding material, L (m): winding length, S (m 2 ): The cross-sectional area of the winding.

[0025] Furthermore, by using an aluminum alloy with a high Al content, i.e., with few impurity elements, for the windings, the windings from used motors can be disposed of as scrap iron without being separated from the motor core. This is because Al is used as an element to improve the magnetic properties of electrical steel sheets, and is an element that is actively added when manufacturing electrical steel sheets in electric furnaces, etc.

[0026] The Cu content of the aluminum alloy must be between 0.001% and 0.15%. If a large amount of Cu is mixed in when a used motor is turned into scrap iron, it is difficult to remove the Cu from the steel. The mixed Cu hinders grain growth when the scrap iron is turned into electrical steel sheet again, degrading the magnetic properties of the electrical steel sheet. Therefore, the Cu content of the aluminum alloy must be 0.15% or less. On the other hand, adding Cu to the aluminum alloy has the effect of improving strength, which is effective when winding the windings around the stator core with a high space factor. For this reason, the Cu content must be 0.001% or more.

[0027] [Stator core] Next, we will explain the requirements for the electromagnetic steel sheets that make up the stator core and the reasons for their limitations. Note that the effects of the invention can be achieved as long as the electromagnetic steel sheets have the specified magnetic properties, and the effects of the invention do not depend on other components, sheet thickness, or manufacturing method.

[0028] The Cu content of the electrical steel sheet is preferably 0.001% or more and 1.0% or less. By reducing the amount of Cu mixed in when a used motor is turned into iron scrap, it is easier to remove Cu from the steel. Furthermore, by reducing the amount of Cu mixed in the iron scrap, it is possible to effectively prevent Cu from interfering with grain growth when the iron scrap is turned into electrical steel sheet again, thereby further improving the magnetic properties of the electrical steel sheet. Therefore, the Cu content of the electrical steel sheet is preferably 1.0% or less. On the other hand, because Cu increases the strength of the steel sheet and contributes to higher motor rotation speeds, the Cu content is preferably 0.001% or more.

[0029] Integral magnetic flux density IB(500): 90,000TA / m or more Integral magnetic flux density IB(5): 550TA / m or more In order to reduce the current in the above formula (1), it is important to reduce the motor current. By using a material with an integral magnetic flux density IB(500) of 90,000 TA / m and an integral magnetic flux density IB(5) of 550 TA / m or more, motor torque can be improved over a wide range from low to high torque, motor current can be reduced, and copper loss (aluminum loss) can be reduced. The integral magnetic flux density IB(500) is preferably 95,000 or more, more preferably 100,000 or more. The integral magnetic flux density IB(5) is preferably 600 or more, more preferably 620 or more. The upper limit of the integral magnetic flux density IB(500) is not particularly limited, but in one example it is 150,000 or less. The upper limit of the integral magnetic flux density IB(5) is not particularly limited, but in one example it is 700 or less.

[0030] Here, the integrated magnetic flux density IB is a value obtained by the following measurement method. (1) DC BH curve measurement The DC BH curve is measured by measuring the magnetic flux density B (T) of the iron core material at the following magnetic field strengths H (A / m): For example, the DC BH curve is measured using data at 0, 10, 20, 30, 40, 50, 60, 70, 80, 100, 125, 150, 175, 200, 250, 300, 400, 500, 800, 1000, 1500, 2000, 2500, 3000, 4000, 5000, 8000, 10,000, 15,000, 20,000, 30,000, and 50,000 A / m.

[0031] (2) Perform numerical integration The obtained DC BH curve is integrated over the range of magnetic field strength H from 0 A / m to 500 A / m, and the obtained value is designated as IB(5). Similarly, the obtained BH curve is integrated over the range of magnetic field strength H from 0 A / m to 50,000 A / m, and the obtained value is designated as IB(500).

[0032] The DC BH curve can be measured by a ring measurement with an excitation coil and a search coil wound around the back yoke of the stator core, or by an Epstein test using the electromagnetic steel sheet to be used in the stator core. Figure 1 shows an example of a DC BH curve measurement. The integrated magnetic flux density IB(5) corresponds to the area of the shaded area shown in Figure 1. Furthermore, Figure 2 shows examples of the integrated magnetic flux density evaluated by the above-mentioned method for four types of electromagnetic steel sheet (corresponding to materials A, B, C, and D in Table 1). The integrated magnetic flux density IB is different from the B which has traditionally been used as an index of the magnetic flux density of electromagnetic steel sheet. 50 The magnitude trends do not necessarily coincide with those of indicators such as . When copper is used as the winding material, it is relatively easy to reduce the resistance of the winding. In contrast, when aluminum is used as the winding material, copper loss (aluminum loss) at low currents (torque conditions) that was not an issue when copper was used as the winding material can become an issue. Through their own intensive research, the inventors have found that using electrical steel sheets with high integrated magnetic flux density IB(5) and integrated magnetic flux density IB(500) is effective in improving loss at low currents.

[0033] The ratio of the motor core's stack height h to its outer diameter D, D / h: 1.0≦D / h≦3.0 According to Equation (1), thickening and shortening the winding wire is effective in reducing copper loss (aluminum loss). Adjusting the integral magnetic flux density IB(500) and integral magnetic flux density IB(5) of the magnetic steel sheets to reduce motor current and thickening and shortening the winding wire to reduce winding resistance effectively reduces copper loss (aluminum loss). Shortening the lamination height h also shortens the winding length L, which is advantageous for reducing copper loss (aluminum loss). In addition, increasing the outer diameter D and expanding the slot area allows for the use of thicker winding wire, which increases the cross-sectional area S of the winding while maintaining the winding length L, which is advantageous for reducing copper loss (aluminum loss). Therefore, a larger ratio D / h of the lamination height h to the outer diameter D is preferable from the perspective of suppressing copper loss (aluminum loss). Furthermore, to effectively prevent magnetic flux leakage in the lamination direction and further reduce copper loss (aluminum loss), D / h is set to 3.0 or less. More preferably, 1.5≦D / h. Furthermore, more preferably, D / h≦2.0.

[0034] Winding slot space factor is 60% or more It is preferable that the slot space factor of the winding is 60% or more. By improving the slot space factor, the cross-sectional area S of the winding can be made larger, which is effective in reducing copper loss (aluminum loss). It is more preferable that the slot space factor is 50% or more. The slot space factor of the winding is defined by the following equation (2). Slot space factor (%) = (conductor cross-sectional area + coating cross-sectional area) / (slot cross-sectional area - insulator cross-sectional area) × 100 ... (2)

[0035] The slot space factor can be evaluated by cutting the stator and analyzing the image of the cross section.

[0036] In particular, it is preferable that the cross section of the winding is rectangular (a rectangular wire), since a rectangular cross section of the winding makes it easier to apply the winding to the stator core with a high space factor.

[0037] Although there is no particular upper limit to the slot space factor of the winding, it is preferably 90% or less. By setting the slot space factor of the winding to 90% or less, stress applied to the electromagnetic steel sheets by the winding can be effectively prevented during sudden heat generation and temperature rises. Rapid heat generation due to heat generated by the winding can occur during driving with a large current, such as when starting or traveling uphill. Compared to copper, aluminum has a higher resistance to the winding, resulting in a large amount of heat generated when current is passed through it. Furthermore, aluminum has a low thermal conductivity, making it difficult to cool, and therefore prone to temperature rises. Furthermore, the thermal expansion coefficient of aluminum (23.9 × 106 / °C) is higher than that of copper (16.5 × 106 / °C). During sudden heat generation and temperature rises, the thermally expanded winding can apply stress to the electromagnetic steel sheets. However, setting the slot space factor of the winding to 90% or less provides sufficient space, effectively preventing stress from being applied to the electromagnetic steel sheets by the winding.

[0038] Iron loss W when an external stress of 10 MPa is applied in a direction perpendicular to the magnetic flux of the electrical steel sheet 10 / 400 (W / kg) is the iron loss W under 0 MPa external stress 10 / 400 (W / kg) or less Iron loss W when an external stress of 10 MPa is applied in a direction perpendicular to the magnetic flux 10 / 400 (W / kg) is the iron loss W under 0 MPa external stress 10 / 400 Even when stress is applied to the electromagnetic steel sheets due to thermal expansion of the windings, by keeping the iron loss equal to or less than the iron loss when no stress is applied, it is possible to suitably prevent the motor characteristics from deteriorating when the above-mentioned stress is applied.

[0039] Iron loss W when an external stress of 10 MPa is applied in a direction perpendicular to the magnetic flux of an electrical steel sheet 10 / 400 (W / kg), and iron loss W at external stress 0 MPa 10 / 400 The evaluation of (W / kg) is carried out as follows. The evaluation method is a single sheet evaluation. The iron loss is evaluated when excited at 1.0 T and 400 Hz with an external stress of 10 MPa applied in the direction perpendicular to the magnetic flux. For Epstein evaluation, surface pressure is applied according to the single sheet evaluation method shown in Reference 1. [Reference 1] Senda et al., "Study on magnetic measurement method under stress of electrical steel sheet", IEEJ Transactions on Electrical Engineering, Vol. 137, No. 11, pp. 654-660 (2017)

[0040] The magnetic steel sheets are preferably laminated by bonding (adhesive lamination), because adhesive lamination allows the magnetic steel sheets to have no plastically processed regions such as caulking, and allows for a higher integrated magnetic flux density to be obtained.

[0041] The layers of the magnetic steel sheets are bonded together with an area ratio of 85% or more. When adhesive lamination is used, it is preferable that the interlayer adhesion ratio of the magnetic steel sheets be 85% or more. Adhesive lamination with an area ratio of 85% or more can increase the rigidity of the stator core. Therefore, when the high-space-factor windings thermally expand, the stress applied to the stator core is more uniform than when laminated using caulking or other methods, and deterioration of magnetic properties during stress application can be more effectively suppressed. Even when the D / h ratio is 1.0≦D / h≦3.0, the rigidity of the stator core can be increased compared to when laminated using caulking or other methods, and increases in motor vibration and noise due to electromagnetic excitation force can be more effectively suppressed. Note that adhesives commonly used for cut cores can be used, including acrylic and epoxy adhesives. The interlayer adhesion ratio of the magnetic steel sheets is measured as follows: The laminated magnetic steel sheets are peeled off, and the area of adhesive remaining on the peeled surface of the two previously bonded magnetic steel sheets is evaluated. The two magnetic steel sheets are evaluated because peeling may occur at the magnetic steel sheet-adhesive interface. The ratio of the adhesive area thus evaluated to the area of the stator core is evaluated as a percentage.

[0042] The corners of the electromagnetic steel sheet that come into contact with the windings should be on the punched shear surface side. When electromagnetic steel sheets are stamped into stator cores, each electromagnetic steel sheet S has a punched shear surface and a fracture surface after processing, as shown in Figure 4. The fracture surface may have burrs, and if the burrs come into contact with the winding A, the insulation of the winding A may be damaged. In particular, when the winding A has a rectangular cross section, the winding A may be shaped by inserting a hairpin-shaped winding A into a slot, bending the tip that protrudes from the electromagnetic steel sheet, and welding it to the tip of the adjacent winding A. In this process, if the burrs are present on the end surface on the bent side, they may come into contact with the bent winding, causing insulation breakdown. Therefore, by positioning the punched shear surface on the bent side of the winding, as shown in Figure 4, a stator with a lower risk of insulation breakdown can be provided.

[0043] To prevent dielectric breakdown, insulating paper is typically applied to cover the cross section of the magnetic steel sheet in the slot before winding the winding. By placing the corners of the magnetic steel sheet that come into contact with the winding on the punched shear surface side, the stator does not need to have insulating paper. Not using insulating paper in the stator can further reduce manufacturing costs. Furthermore, not using insulating paper allows the winding to be designed to be thicker, which reduces copper loss (aluminum loss), which is a problem with windings made of aluminum alloy, and further improves motor performance.

[0044] The stator is preferably subjected to a varnish impregnation treatment after windings are applied to the stator core. [Example]

[0045] (Example 1) Effect of integrated magnetic flux density The magnetic steel sheets listed in Table 1 were laminated and punched to prepare the stator shown in Figure 3. An 8-pole, 48-slot IPM motor with an outer diameter D of 200 mm and a lamination thickness h of 100 mm was fabricated. The DC BH curves of the magnetic steel sheets were determined in advance using an Epstein test, and the integral magnetic flux density IB(5) and IB(500) were evaluated. The windings were made of rectangular aluminum alloy wire composed of 99.7% Al and 0.05% Cu. The slot space factor of the windings was 65%. The torque of the motors fabricated using each magnetic steel sheet was measured at a rotational speed of 1500 rpm and currents of 300 A and 50 A. The motors were mechanically connected to a load test machine via a coupling and measured using a torque meter installed between the motor and the load test machine. The torque for Material B was set at 100 (reference), and the results are shown in Table 1. FIG. 5 shows a graph in which the horizontal axis represents the integrated magnetic flux density IB(5) and the integrated magnetic flux density IB(500) and the vertical axis represents the torque.

[0046] The results showed that the higher the integral magnetic flux density IB(5), the higher the torque at 50 A, and the higher the integral magnetic flux density IB(500), the higher the torque at 300 A. Furthermore, electrical steel sheets with an integral magnetic flux density IB(500) of 90,000 TA / m or higher and an integral magnetic flux density IB(5) of 550 TA / m or higher can demonstrate significantly high motor torque, deviating from the above correlation.

[0047] (Example 2) Effect of D / h A motor was fabricated with the outer diameter D and inner diameter d of the stator core as shown in Figure 3, and D / h was varied by changing the stacking height. A rectangular aluminum alloy wire consisting of 99.7% Al and 0.05% Cu was used for the windings. The slot space factor was 65%, equivalent to that of Example 1. Table 2 shows the results of evaluating the torque when driven at a rotational speed of 1500 rpm and a current of 300 A, with the measured value for Material B set at 100 (reference). Figure 6 also shows the relationship between D / h and torque for Example 2, an example of the invention. Figure 6 reveals that the torque improvement effect is particularly large when the condition 1.0≦D / h≦3.0 is satisfied.

[0048] (Example 3) Effect of iron loss under surface pressure For materials B, E, F, and G of Example 1, iron loss was evaluated in a single-plate test when an external stress of 10 MPa was applied in the direction perpendicular to the magnetic flux (surface pressure) and the material was excited at 1.0 T and 400 Hz. Table 4 shows the ratio of iron loss when a stress of 10 MPa was applied to iron loss when no stress was applied. Furthermore, the efficiency of a motor using a stator with an outer diameter D, inner diameter d, and lamination height h of 170 mm shown in Figure 3 was evaluated using the following procedure. The slot space factor of the winding was 65%. (1) 4000 rpm - 50 A: Motor efficiency measured in steady state (2) 4000 rpm - 300 A: 20 seconds (3) Driven at 4000 rpm and 50 A: Motor efficiency measured immediately after changing the current Motor efficiency is the ratio (Po(W) / Pi(W)) of the input power Pi(W) to the motor's output Po(W) = torque T(Nm) x rotation speed (rpm) x 2π / 60, evaluated as a percentage.

[0049] The change in motor efficiency (difference in percentage (%), hereinafter also referred to as points) between (1) and (3) is shown in Table 3. In addition, the iron loss (W 10 / 400 ) when a stress of 10 MPa is applied to the iron loss (W 10 / 400 ) ratio and the change in motor efficiency are shown in Fig. 7. Iron loss (W 10 / 400 ) when a stress of 10 MPa is applied to the iron loss (W 10 / 400 ) ratio, the smaller the change in motor efficiency. In other words, the decrease in motor efficiency is small even immediately after operation under high-current conditions such as (2). The reason for this difference in motor efficiency change depending on the magnetic steel sheet material is thought to be as follows: When the motor is operated as in (2), the windings instantaneously heat up, and the aluminum winding material thermally expands, generating stress on the teeth, which changes the iron loss of the material itself and ultimately the motor iron loss. However, for materials E and F, which have good iron loss characteristics under contact pressure, the change in motor iron loss, or motor efficiency, due to this stress is small. On the other hand, for materials B and G, which have poor iron loss characteristics under contact pressure, the motor efficiency changed significantly (deteriorated). Furthermore, in material evaluations of materials E and F, the iron loss decreased when stress was applied, while the motor efficiency decreased. This is thought to be because the increase in copper loss (aluminum loss) caused by the increase in resistivity ρ due to the rise in winding temperature offset the decrease in iron loss, with the former being greater.

[0050] (Example 4) Effect of Adhesion Area The influence of the processing method of the electromagnetic steel sheets on the motor efficiency and noise was evaluated for the IPM motor shown in Figure 3. Using material F or B from Example 1 and using either caulking or adhesive lamination as the lamination method, the motor noise (dB) and motor efficiency (%) were evaluated at a rotation speed of 4500 rpm and a torque of 50 Nm. Here, the motor noise was evaluated by placing a sound level meter 0.5 m from the coil end in the extension direction of the motor's rotating shaft and comparing the overall noise value. The evaluation results of the motor manufactured by crimping were used as the standard, and the changes from these evaluation results are shown in Table 4. Figure 8 also shows the relationship between the bonding area and the motor noise (dB) and motor efficiency (%).

[0051] In terms of motor efficiency and motor noise, better characteristics were obtained than in motors manufactured using crimping under all conditions. In particular, with Material F, the greater the adhesive area, the greater the improvement in motor efficiency and motor noise. On the other hand, as shown in Table 3, under the condition of Material B, where iron loss increases with the application of stress, adhesive lamination achieved better motor characteristics than lamination using crimping, but no further improvement in motor characteristics was observed even when the adhesive area was increased. This is thought to be because the compressive stress caused by adhesive lamination had an adverse effect on magnetic properties, leading to increased iron loss and increased current due to a decrease in magnetic permeability.

[0052] (Example 5) Effects of punched shear surface and insulating paper Next, the effects of punched shear surfaces and insulating paper on the IPM motor characteristics shown in Figure 3 were verified using material A. Stators were formed from electromagnetic steel sheets by punching, laminated under the conditions shown in Table 5, and then windings were applied. Ten motors were fabricated for each condition, varying the winding material and whether or not insulating paper was used. Table 5 shows the results of evaluating the rate at which short circuits occurred between the electromagnetic steel sheets and windings. The rate at which short circuits occurred was determined by using a megaohm tester to evaluate the resistance between the UVW phase motor terminals and the outer periphery of the stator core. A resistance of 1 kΩ or less was detected, which was determined to be a short circuit.

[0053] When insulating paper was inserted, no short circuits occurred under any of the conditions. On the other hand, when insulating paper was not used and the winding was inserted in a direction that would cause contact with the burrs, short circuits occurred between the magnetic steel sheet and the winding. The rate of short circuits was higher for aluminum alloy windings than for windings made of copper (Cu ≥ 99.95%), a commonly used magnet wire material. This is thought to be due to the low strength of the aluminum alloy winding material, which causes the winding to stretch due to stress applied to the winding material during the winding process, leading to a deterioration in insulation performance due to the stretching of the insulating coating. However, when the winding was inserted from the opposite direction to the burrs, i.e., when the corner of the magnetic steel sheet that contacts the winding was on the punched shear surface side, short circuits were suppressed even when the aluminum winding was wound without insulating paper. Thus, controlling the winding insertion direction can effectively suppress short circuits between the magnetic steel sheet and the winding without using insulating paper, thereby improving motor manufacturing yield. Furthermore, by not using insulating paper, the windings can be designed to be thicker, which reduces copper loss (aluminum loss), which is a problem when using windings made of aluminum alloy, and is effective in further improving motor performance.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Table 3]

[0057] [Table 4]

[0058] [Table 5] [Explanation of symbols]

[0059] 10 stator core 11 Back Yoke 12 slots 13 Teeth S Electrical steel sheet A winding

Claims

1. a stator core formed by laminating electromagnetic steel sheets; a winding wound around the stator core; Equipped with the winding is made of an aluminum alloy containing, by mass%, 99.6% or more of Al and 0.001% or more and 0.15% or less of Cu, The integrated magnetic flux density IB(500) of the electromagnetic steel sheet is 90,000 TA / m or more and the integrated magnetic flux density IB(5) is 550 TA / m or more, A stator in which the iron loss W 10 / 400 (W / kg) when an external stress of 10 MPa is applied in a direction perpendicular to the magnetic flux of the electromagnetic steel plate is 0.98 or less relative to the iron loss W 10 / 400 (W / kg) when no external stress is applied to the electromagnetic steel plate. Here, the integrated magnetic flux density IB(500) refers to the integral value of the magnetic flux density (T) in the range where the magnetic field strength H is 0 A / m to 50,000 A / m, The integrated magnetic flux density IB(5) indicates the integral value of the magnetic flux density (T) in the range of the magnetic field strength H from 0 A / m to 500 A / m.

2. 2. The stator according to claim 1, wherein a ratio D / h of a stack height h to an outer diameter D of the stator core satisfies 1.0≦D / h≦3.

0.

3. 3. The stator according to claim 1, wherein the slot space factor of the winding is 60% or more.

4. 3. The stator according to claim 1, wherein the layers of the electromagnetic steel sheets are bonded together at an area ratio of 85% or more.

5. the electromagnetic steel sheet has a punched shear surface, a corner of the electromagnetic steel sheet that comes into contact with the winding is on the punched shear surface side, 3. The stator according to claim 1, wherein the stator does not include insulating paper.

6. The stator according to claim 1 or 2, wherein the electromagnetic steel sheet contains, by mass%, Cu: 0.001% or more and 1.0% or less.

7. A motor comprising the stator according to claim 1 or 2.

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