Stators and rotating electric machines

Abstract

This rotating electric machine comprises a rotor (400) and a stator (300) which is disposed around the rotor (400), the stator (300) being provided with: a stator core (1); a stator coil (2) wound around the stator core (1); and a plurality of support members (4) that hold the stator coil (2) by being inserted between adjacent turns of the stator coil (2) in a coil end (7) where the stator coil (2) is protruding, and that have a total contact area with the stator coil (2) larger at a coil end tip part (7b) located away from the stator core (1) than at a coil end root part (7a) located close to the stator core (1).

Description

Technical Field

[0001] The present disclosure relates to a stator and a rotating electrical machine.

Background Art

[0002] A rotating electrical machine is composed of a rotor and a stator, and the stator converts the change in the magnetic field generated by the rotation of the rotor into electrical energy. The stator has a stator core and coils wound around the stator core with coil ends protruding from both ends of the stator core. Due to the magnetic field generated during the operation of the rotating electrical machine, an electromagnetic force with a frequency twice that of the operating frequency acts on the stator, causing vibration.

[0003] In order to suppress this vibration, it has been proposed to provide an adhesion adjustment member and an insulating member between the stator coils of the coil ends. For example, in Patent Document 1, a tape having a predetermined surface adhesiveness is used as the adhesion adjustment member, and it is interposed between the stator coils facing each other and the insulating member filled between a plurality of stator coils, so that the natural frequency is adjusted to be lower than the excitation frequency by the electromagnetic force to prevent resonance by the electromagnetic force.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, during the operation of the rotating electrical machine, the temperature rises due to the influence of Joule heat caused by the electromotive force, the interlinked magnetic flux, etc. In conventional rotating electrical machines, there is a problem that the adhesion adjustment member and the insulating member between the stator coils hinder cooling.

[0006] This disclosure was made to solve the problems described above, and aims to provide a rotating electric machine that can suppress vibrations generated during operation while suppressing the temperature rise of the coil end. [Means for solving the problem]

[0007] The stator according to this disclosure comprises a stator core, stator coils wound around the stator core, and a plurality of support members inserted between adjacent stator coils at the coil ends from which the stator coils protrude, holding the stator coils, and having a larger total contact area with the stator coils at the tip of the coil end further from the stator core than at the root of the coil end closer to the stator core. [Effects of the Invention]

[0008] According to this disclosure, vibration of the coil end can be suppressed, and the flow rate of cooling air to the base of the coil end where the coil temperature is high can be increased, thereby suppressing the rise in coil temperature at the base of the coil end. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view showing the conceptual configuration of a rotating electric machine according to Embodiment 1. [Figure 2] This is a side view showing the end of the stator of a rotating electric machine according to Embodiment 1. [Figure 3] This is a view from direction A in Figure 2, according to Embodiment 1. [Figure 4] This graph shows the relationship between the coil end axial position and coil temperature according to Embodiment 1. [Figure 5] This is a view from direction A in Figure 2, according to Embodiment 2. [Figure 6] This is a view from direction A in Figure 2, according to Embodiment 3. [Modes for carrying out the invention]

[0010] Embodiment 1. The rotating electric machine in Embodiment 1 will be described using Figures 1, 2, and 3. As shown in Figure 1, the rotating electric machine 100 has a stator 300 supported and fixed to a frame 200, and a rotor 400 that is rotatably supported, and the stator 300 converts the change in the magnetic field generated by the rotation of the rotor 400 into electrical energy. Figure 2 is a side view showing the end of the stator 300 of the rotating electric machine according to Embodiment 1. The stator 300 of the rotating electric machine comprises a stator core 1 in which magnetic plates are stacked, and stator coils 2 wound around the stator core 1. The stator coils 2 comprise a plurality of upper stator coils 2a and a plurality of lower stator coils 2b, and the ends of the upper and lower stator coils 2a and 2b protrude from the end 1a of the stator core 1 and are electrically connected to form coil ends 7. A plurality of insulating rings 3 are inserted between the upper and lower stator coils 2a and 2b to hold the coil ends 7 in an annular shape. The outer circumference of the lower stator coil 2b is supported by the coil end fixing plate 5.

[0011] Multiple upper and lower stator coils 2a and 2b are adjacent to each other with gaps between them, and support members 4 are inserted between adjacent upper stator coils 2a and lower stator coils 2b. The support members 4 maintain a constant gap between adjacent upper stator coils 2a and lower stator coils 2b while ensuring rigidity. The dimensions and shape of the support members 4 are such that, for example, if the gap between adjacent upper stator coils 2a and lower stator coils 2b is about 1 cm, the support member 4 has a thickness of about 1 cm and is a rectangular shape with a contact surface of about 4 cm on each side with the upper or lower stator coils 2a and lower stator coils 2b. Here, the dimensions of the contact surface of the support member 4 are the same regardless of its position.

[0012] The number of support members 4 and the dimensions of their contact surfaces affect the natural frequency of the coil end 7. Increasing at least one of the number of support members or the dimensions of their contact surfaces increases the natural frequency of the coil end 7. In other words, the number of support members 4 and the dimensions of their contact surfaces are determined such that the natural frequency of the coil end 7 is greater than the excitation frequency due to electromagnetic force.

[0013] The coil end fixing plate 5, the upper and lower stator coils 2a and 2b, the insulating ring 3, and the support member 4 are bound together with insulating tape 6, and the coil end 7 is fixed as a single unit.

[0014] The coil end 7 is cooled from the outside by a cooling airflow 8 that flows from the inner diameter side to the outer diameter side of the stator 300 through the gap between the upper and lower stator coils 2a and 2b, the insulating ring 3, the support member 4, and the coil end fixing plate 5.

[0015] Figure 3 is a view from direction A in Figure 2. The coordinate system is shown in the lower right of the figure, with direction C representing the circumferential direction and direction A representing the axial direction. When considering a length L in the axial direction (not along the coil end 7) with the end 1a of the stator core 1 (the base of the coil) as the starting point O and the tip 7c of the coil end 7 as the ending point, the side closer to the starting point O is defined as the coil end base 7a, the side closer to the tip and further away from the coil base is defined as the coil end tip 7b, and the boundary between the coil end base 7a and the coil end tip 7b is defined as boundary BD. The support member 4 is not placed at the coil end base 7a, but at the coil end tip 7b.

[0016] Figure 4 shows a comparison of the temperature distribution, particularly at the 0-1 / 2L position where the coil temperature is high, for each condition where the boundary BD is changed to 1 / 2L (Figure 4a), 1 / 3L (Figure 4b), and 1 / 4L (Figure 4c), compared to a conventional coil end (Figure 4d). The horizontal axis represents the distance from the starting point O, and the vertical axis represents the internal temperature of the upper stator coil 2a that constitutes the coil end 7. The coil corner section 7d (shown in Figure 3), where the upper and lower stator coils 2a and 2b have a curved shape, becomes hot due to the high magnetic flux density and the thick coil insulation caused by the curved shape, making cooling difficult. In other areas, the temperature becomes high at the position where the support member 4 is placed because the airflow of cooling air is obstructed. On the other hand, when the boundary BD is 1 / 2L, 1 / 3L, and 1 / 4L (Figures 4a-c), although the coil temperature rises slightly at the coil corner section 7d, the rise can be made significantly smaller compared to the conventional coil end (Figure 4d). This is because the absence of the support member 4 allows for a greater flow of cooling air, resulting in concentrated cooling. In particular, when the boundary BD is set to 1 / 2L (Figure 4a), the coil temperature can be significantly reduced at the coil corner 7d, resulting in a high cooling effect.

[0017] As described above, the heat generated by the high magnetic flux density is concentrated particularly in the coil corner 7d. Therefore, the boundary BD should be positioned at a location between 1 / 4L and 1L from the starting point O, and more preferably between 1 / 3L and 1L, so that the coil corner 7d falls within the area without the support member 4. Setting it to around 1 / 2L can further enhance the cooling effect. The support member 4 should be positioned appropriately from the viewpoint of vibration suppression. Specifically, as mentioned above, its position should be determined so that its natural frequency is greater than the excitation frequency due to electromagnetic force.

[0018] Thus, by arranging the support member 4 at the coil end tip portion 7b instead of at the coil end root portion 7a, the ventilation resistance of the coil end root portion 7a, where the magnetic flux density is higher and the temperature is more likely to rise compared to the coil end tip portion 7b, is suppressed to be low, and more cooling air can flow. Therefore, the rise in the temperature of the stator coil at the coil end root portion 7a can be suppressed. Further, since the coil end root portion 7a where the temperature is more likely to rise can be intensively cooled, the axial temperature distribution of the coil end 7 can be made uniform.

[0019] Embodiment 2. FIG. 5 is a view seen in the arrow direction from the A direction in FIG. 2. A coordinate system is shown in the lower right of the figure, where the C direction represents the circumferential direction and the A direction represents the axial direction. In Embodiment 1, an example where the support member 4 is not arranged at the coil end root portion 7a was shown. In Embodiment 2, an example where a smaller number of support members 4 than at the coil end tip portion 7b are also arranged at the coil end root portion 7a is shown. The description of the same configuration as in Embodiment 1 is omitted. The same reference numerals as in FIG. 3 in FIG. 5 indicate the same or corresponding parts.

[0020] The dimensions and shape of the support member 4 are, as in Embodiment 1, a rectangular parallelepiped having a thickness approximately the same as the gap between the adjacent upper and lower stator coils 2a, 2b and having contact surfaces with the upper and lower stator coils 2a, 2b. The contact surface dimensions of the support member 4 are the same regardless of the position where it is arranged.

[0021] In the coil end 7 shown in Figure 5, the boundary BD is set to, for example, 2 / 5L. The number of support members 4 placed at the coil end base 7a is less than the number of support members 4 placed at the coil end tip 7b. The support members 4 placed at the coil end base 7a are effectively placed in other gaps, rather than in the gaps between the upper and lower stator coils 2a and 2b, where the temperature becomes relatively higher at each axial position due to the difference in circumferential magnetic flux density caused by the difference in current phase flowing through the upper and lower stator coils 2a and 2b, respectively. For example, in the case of a stator 300 having 72 upper and 72 lower stator coils 2a and 2b, two upper and two lower stator coils 2a and 2b become hot at every 60-degree interval on the circumference of the coil end 7. For this reason, in the coil end base 7a shown in Figure 5, support members 4 are not placed in the three gaps adjacent to the two upper stator coils 2c that become hot. Furthermore, since six locations are set at 60-degree intervals where no support member 4 is placed, 18 (1 / 4) support members 4 are reduced in the circumferential direction. The same applies to the support members 4 placed between the lower stator coils 2b. In other words, the ratio of the number of support members 4 placed at each axial position of the coil end base 7a and the coil end tip 7b is 3:4.

[0022] Here, an example is shown where the boundary BD is 2 / 5L, but it can be determined in the same way as in Embodiment 1. The ratio of the number of support members 4 positioned at each axial position of the coil end root portion 7a and the coil end tip portion 7b can be, for example, 1:5 to 3:4, and 1:4 is even more preferable. The support members 4 are positioned appropriately from the viewpoint of vibration suppression. Specifically, their positions should be determined so that their natural frequencies are greater than the excitation frequency due to electromagnetic force.

[0023] In this way, by reducing the number of support members 4 placed at the coil end base 7a compared to the number of support members 4 placed at the coil end tip 7b, the airflow resistance at the coil end base 7a is kept low, allowing more cooling air to flow. Consequently, the rise in the stator coil temperature at the coil end base 7a can be suppressed. Furthermore, since the upper and lower stator coils 2a and 2b, which are prone to temperature increases at the coil end base 7a, can be cooled intensively, the axial temperature distribution of the coil end 7 can be made uniform.

[0024] Furthermore, if the support member 4 is not placed in the gap between the upper and lower stator coils 2a and 2b, where the surrounding area is relatively hotter, but rather in other gaps at the coil end base 7a, the upper and lower stator coils 2a and 2b, which are hotter, can be cooled intensively. As a result, not only the axial temperature distribution of the coil end 7 but also the circumferential temperature distribution of the coil end base 7a can be made uniform.

[0025] In Embodiments 1 and 2, examples were shown in which the dimensions and shape of all the support members 4 are the same, but some may have different shapes and dimensions.

[0026] Embodiment 3. Figure 6 is a view from direction A in Figure 2. The coordinate system is shown in the lower right of the figure, with direction C representing the circumferential direction and direction A representing the axial direction. Embodiments 1 and 2 show examples of changing the number of support members 4 arranged on the coil end 7, while Embodiment 3 shows an example of changing the contact surface dimensions of the support members 4. The same configuration as in Embodiments 1 and 2 will not be explained. In Figure 6, the same reference numerals as in Figure 3 indicate the same or corresponding parts.

[0027] Of the support members 4, the support member 4a positioned in a part of the coil end root portion 7a has a smaller contact surface dimension compared to the other support members 4b. For example, the radial length of the contact surface dimension of support member 4a is set to 4 cm and the axial length to 2 cm. The contact surface dimension of support member 4b is the same as that of support member 4 in Embodiment 1. Since support members 4a and 4b maintain a constant gap between adjacent upper or lower stator coils 2a and 2b, their thickness is the same as in Embodiments 1 and 2.

[0028] In the coil end 7 shown in Figure 6, the boundary BD is set to, for example, 4 / 9L. The contact surface dimensions of the support member 4a, which is positioned in a part of the coil end root portion 7a, are smaller than the contact surface dimensions of the support member 4 shown in Embodiments 1 and 2. The position is effective if it is, for example, between the upper and lower stator coils 2a and 2b, where the temperature is relatively higher at each axial position due to the difference in circumferential magnetic flux density caused by the difference in current phase flowing through the upper and lower stator coils 2a and 2b, respectively. As explained in Embodiment 2, for example, in the case of a stator 300 having 72 upper and lower stator coils 2a and 2b, two upper and lower stator coils 2a and 2b become hot at every 60-degree intervals on the circumference of the coil end 7. For this reason, in the coil end root portion 7a shown in Figure 6, support members 4a with small contact surface dimensions are positioned in the three gaps adjacent to the two upper stator coils 2c that become hot. Furthermore, since six locations for positioning the support members 4a are set at 60-degree intervals, 18 support members 4a are arranged in the circumferential direction. The same applies to the support members 4a positioned between the lower stator coils 2b.

[0029] Here, an example is shown where the boundary BD is 4 / 9L, but it can be determined in the same way as in Embodiment 1. For example, the ratio of the contact surface dimensions of the support member 4 at the coil end base 7a and the coil end tip 7b can be 1:4 to 2:3, preferably 1:2. The support members 4a and 4b are arranged to be in an appropriate position and of appropriate dimensions from the viewpoint of vibration suppression. Specifically, the position and contact surface dimensions should be determined so that the natural frequency is greater than the excitation frequency due to the electromagnetic force.

[0030] In this way, by making the contact surface dimension of at least one of the support members 4 located at the coil end base 7a with the stator coil 2 smaller than the contact surface dimension of the support member 4 located at the coil end tip 7b with the stator coil 2, the airflow resistance at the coil end base 7a is kept low, and more cooling air flows. Therefore, the rise in the stator coil temperature at the coil end base 7a can be suppressed. In addition, since the upper and lower stator coils 2a and 2b, which are prone to temperature rise at the coil end base 7a, can be cooled intensively, the axial temperature distribution of the coil end 7 can be made uniform.

[0031] Furthermore, at the base of the coil end 7a, a support member 4a with a smaller contact surface dimension than the support member 4 of Embodiments 1 and 2 is placed between the upper and lower stator coils 2a and 2b, where the surrounding area is relatively hotter. This allows for concentrated cooling of the upper and lower stator coils 2a and 2b, which are hotter. As a result, not only the axial temperature distribution of the coil end 7 but also the circumferential temperature distribution of the base of the coil end 7a can be made uniform.

[0032] In this embodiment, an example is shown in which a support member 4a with a contact surface dimension smaller than that of the support member 4 is placed on a part of the coil end base portion 7a, but it may also be placed on the coil end tip portion 7b. Furthermore, in Embodiment 3, all of the support members placed on the coil end base portion 7a may be support members 4a with a contact surface dimension smaller than that of the support member 4.

[0033] Furthermore, in addition to the above, it is possible to freely combine each embodiment, modify any component of each embodiment, or omit any component of each embodiment. [Explanation of Symbols]

[0034] 100 Rotating electric machine, 200 Frame, 300 Stator, 400 Rotor, 1 Stator core, 2 Stator coil, 2a Upper stator coil, 2b Lower stator coil, 3 Insulating ring, 4, 4a, 4b Support member, 5 Coil end fixing plate, 6 Insulating tape, 7 Coil end, 7a Coil end base, 7b Coil end tip, 8 Cooling air

Claims

1. Stator core and The stator coil wound around the aforementioned stator core, At the coil end from which the stator coil protrudes, there are multiple support members that are inserted between adjacent stator coils to hold the stator coil, and the total contact area with the stator coil is larger at the tip of the coil end, which is further from the stator core, than at the base of the coil end, which is closer to the stator core. A stator equipped with a stator.

2. The multiple support members are, The stator according to claim 1, which is not located at the base of the coil end but is located at the tip of the coil end.

3. The number of support members arranged at the base of the coil end is, The stator according to claim 1, wherein the number of support members arranged at the tip of the coil end is less than the number of support members arranged.

4. The contact surface dimension of at least one of the support members positioned at the base of the coil end with the stator coil is, The stator according to claim 1, wherein the contact surface dimension of the support member disposed at the tip of the coil end is smaller than the contact surface dimension of the stator coil with the stator coil.

5. The boundary between the base portion of the coil end and the tip portion of the coil end is, The stator according to any one of claims 1 to 4, wherein the axial length L is defined as the starting point at the end of the stator core and the ending point at the tip of the coil end, and the position is between 1 / 4L and less than 1L.

6. Rotor and A stator according to any one of claims 1 to 4, which is arranged around the rotor, A rotating electric machine equipped with the following features.

7. A rotor and, A stator according to claim 5, which is arranged around the rotor, A rotating electric machine equipped with the following features.

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