Rotary electric machine

Abstract

To provide a rotary electric machine that can prevent a reduction in cooling performance to ensure stable cooling performance.SOLUTION: A rotary electric machine 1 of an embodiment comprises a frame 2 accommodating a rotor 6 and a stator 4. The frame 2 is provided with a channel 9 that is formed inside a wall part 2a and through which coolant flows. The channel 9 is provided with a slope on an inner peripheral side wall surface 10 that forms the channel 9.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a rotating electric machine. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in order to cool a rotating electric machine, as disclosed in, for example, Patent Document 1, it has been proposed to cool the rotating electric machine by providing a flow path through which a coolant flows inside the frame of the rotating electric machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-107888 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such a rotating electrical machine, it is important to ensure cooling performance by preventing variations in the flow of the coolant within the flow passages.

[0005] In view of this, a rotating electric machine capable of suppressing deterioration in cooling performance and ensuring stable cooling performance is provided. [Means for solving the problem]

[0006] The rotating electric machine of the embodiment includes a frame that houses a rotor and a stator, and the frame is provided with a flow passage through which a refrigerant flows that is formed within a wall portion, an inlet through which the refrigerant flows into the flow passage, and an outlet through which the refrigerant flows out of the flow passage, and the flow passage has a slope provided on at least one of the inner wall surface and the outer wall surface that form the flow passage. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a rotating electric machine according to a first embodiment; [Diagram 2] FIG. 2 is a schematic diagram showing a flow path and a flow of a coolant; [Diagram 3] Diagram showing the difference in refrigerant flow with and without a gradient [Figure 4] Figure 1 showing another example of the flow path configuration [Diagram 5] Figure 2 showing another example of the flow path configuration DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the drawings. As shown in Fig. 1, a rotating electric machine 1 includes a frame 2 formed in a hollow shape, a stator 4 fixed to the inner peripheral surface of the frame 2 and having a coil 3 attached thereto, and a rotor 6 disposed on the inner peripheral side of the stator 4 with a predetermined gap therebetween and rotating together with a shaft member 5. In Fig. 1 and other figures, hatching of a wall portion 2a is omitted for the sake of simplicity of explanation.

[0009] In the following description, the center of rotation of the shaft member 5 is referred to as the central axis (J), the direction along the central axis (J) is referred to as the axial direction, the direction around the central axis (J) is referred to as the circumferential direction, and the direction perpendicular to the central axis (J) is referred to as the radial direction. Note that the type and structure of the rotating electric machine 1 shown in Fig. 1 are merely examples, and may be, for example, a permanent magnet type electric motor, an induction type electric motor, or a generator.

[0010] The frame 2 has openings at both ends in the left-right direction in the figure closed by brackets 7, and the brackets 7 are provided with bearings 8 that rotatably support the shaft member 5. The frame 2 is a so-called casting manufactured by casting, and has a flow path 9 through which a refrigerant flows in its wall portion 2a. In a cross-sectional view passing through the central axis (J), the flow path 9 is a space sandwiched between an inner peripheral side wall surface 10 located on the radial inside and an outer peripheral side wall surface 11 located on the radial outside, and is formed by extending in the axial direction within the wall portion 2a.

[0011] 2, the flow path 9 is provided with a partition 14 that separates an inlet 12 through which the refrigerant flows into the flow path 9 from an outlet 13 through which the refrigerant flows out of the flow path 9. The flow path 9, the inlet 12, the outlet 13, and the partition 14 are formed at the same time as the frame 2 is cast. Therefore, as shown by the arrow F1 in the development view developed at the position X1, the refrigerant that flows in from the inlet 12 is guided in the circumferential direction along the partition plate, flows around the frame 2 for approximately one revolution plus α, and then flows out from the outlet 13.

[0012] In this way, the flow passage 9 is formed by expanding the wall portion 2a in the axial direction and also expanding over the entire circumferential direction. In this embodiment, the width (W1) of the flow passage 9 in the axial direction is formed wider than the width (W2) of the stator 4 in the axial direction. Note that α may be set appropriately based on the required cooling performance. The arrangements of the inlet 12 and the outlet 13 and the partition portion 14 illustrated in Figs. 1 and 2 are examples, and an appropriate arrangement can be selected as appropriate, for example, by arranging them near the center in the axial direction.

[0013] In addition, in the flow passage 9, the distance between the inner circumferential wall surface 10 and the outer circumferential wall surface 11 is widest at approximately the center in the axial direction, and the inner circumferential wall surface 10 is provided with a gradient that gradually narrows toward both ends in the axial direction. In the case of this embodiment, the inner circumferential wall surface 10 is provided with a constant gradient of 1%. However, the gradient value shown here is merely an example, and other values ​​may be used.

[0014] Next, the operation and effects of the above-mentioned configuration will be described. As described above, in the rotating electric machine 1 that is cooled by a coolant, it is important to ensure the cooling performance by preventing variation in the flow of the coolant in the flow passages 9. By providing the above-described partitions 14, it is possible to efficiently flow the coolant in the circumferential direction, and it is believed that the cooling performance can be ensured over the entire circumferential direction.

[0015] However, since the coolant spreads and flows in the flow passage 9 after flowing in from the inlet 12, variation in the flow rate occurs in the flow passage 9. Therefore, in this embodiment, a gradient is provided in the flow passage 9 as described above. The refrigerant in the flow passage 9 has a flow velocity (V), a volumetric flow rate (Q), and a cross-sectional area (A) of the flow passage 9, which satisfy the relationship Q=AV. Therefore, by providing a gradient, the distance (L2) between the inner circumferential wall surface 10 and the outer circumferential wall surface 11 at the ends in the axial direction becomes smaller than the distance (L1) between the inner circumferential wall surface 10 and the outer circumferential wall surface 11 at the center, as shown in Fig. 1. Therefore, in the flow passage 9, the cross-sectional area of ​​the ends is smaller than that of the center, and therefore the flow velocity is faster at the ends than at the center.

[0016] Fig. 3 shows the results of a simulation in a comparative example where no gradient is provided, and a simulation in an example where a gradient is provided, at a position corresponding to the position X2 in Fig. 2. In Fig. 3, the flow rate is represented by different hatching, and it is shown that the flow rate is fastest near the center of the comparative example region (R1), the flow rate is relatively slower as it moves away from the center, and the flow rate is slowest at the end of the flow path 9. It is also shown that in the case of region (R2), the flow rate near the center is almost the same as the flow rate near the end of region (R1).

[0017] As shown in Fig. 3, the flow velocities in the regions (R11) and (R12) where a gradient is provided are generally higher than the flow velocities in the regions (R1) and (R2) where no gradient is provided. For example, near the center of the region (R12), the flow velocity is as high as near the center of the region (R1) where no gradient is provided. Furthermore, in the embodiment, the range where the flow velocity is relatively high is widely distributed up to the end side in the axial direction compared to the comparative example. In other words, in the embodiment, the flow velocity can be improved over a wide range in the flow path 9.

[0018] As a result, when heat generated by the coil 3 is transmitted to the frame 2 via the stator 4, efficient heat exchange with the coolant is possible throughout the entire axial and circumferential directions of the frame 2, and since the flow rate is increased, the coolant that has absorbed the heat can be quickly discharged from the frame 2. Furthermore, since the flow rate is increased over a wide range within the flow path 9, it is possible to prevent the coolant that has absorbed the heat from stagnating in certain areas. Even if the flow rate changes depending on the location within the flow path 9, the flow rate per unit time at that location does not change, so it is possible to prevent deterioration or variation in cooling performance.

[0019] According to the embodiment described above, the following effects can be obtained. The rotating electric machine 1 includes a frame 2 that houses a rotor 6 and a stator 4, and the frame 2 is provided with a flow path 9 through which a refrigerant flows, which is formed within a wall portion 2a, and the flow path 9 has an inclination on an inner peripheral wall surface 10 that forms the flow path 9. This allows efficient heat exchange with the refrigerant over the entire axial and circumferential directions of the frame 2, thereby preventing a decrease in cooling performance, and the increased flow rate allows efficient heat discharge, ensuring stable cooling performance.

[0020] Moreover, the flow passage 9 of the rotating electric machine 1 is provided with a gradient such that the inner circumferential wall surface 10 is inclined with respect to the axial direction in a cross-sectional view passing through the central axis (J). This allows the flow rate to be increased in the axial direction of the flow passage 9, and the entire rotating electric machine 1 can be efficiently cooled. That is, the flow passage 9 of the rotating electric machine 1 is provided with a gradient such that the distance between the inner circumferential wall surface 10 and the outer circumferential wall surface 11 at the end in the axial direction becomes relatively narrow in a cross-sectional view passing through the central axis (J). This allows the flow rate to be increased up to the end of the flow passage 9, and heat discharge can be promoted throughout the entire flow passage 9.

[0021] So far, the configuration in which the inner peripheral wall surface 10 is sloped has been illustrated, but the flow path 9 can have other shapes as shown in Fig. 4. Note that Fig. 4 shows a schematic cross-sectional view of the flow path 9 passing through the central axis (J), but hatching of the wall portion 2a of the frame 2 has been omitted for simplicity of explanation.

[0022] For example, as shown in shape example 1, a planar gradient may be provided on both the inner peripheral wall surface 10 and the outer peripheral wall surface 11. Although a gradient is provided across the entire width (W1) of the flow path 9, a gradient may be provided only in a portion of the width direction. With such a configuration, the same effects as those of the embodiment can be obtained.

[0023] Alternatively, as shown in Shape Example 2, a curved gradient, that is, a gradient that is not uniform, may be provided. In this case, at least one of the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 may be provided with a curved gradient. In addition, in combination with Shape Example 1, at least one of the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 may be provided with a flat gradient, and the other may be provided with a curved gradient. With such a configuration, the same effect as in the embodiment can be obtained.

[0024] Alternatively, as shown in the third shape example, at least one of the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 may be provided with a stepped gradient, that is, a shape in which the distance between the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 changes in stages to form a gradient when viewed as a whole. In this case, both the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 may be provided with a stepped gradient, or in combination with other shape examples, at least one of the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 may be provided with a stepped gradient, and the other may be provided with a flat or curved gradient. With such a configuration, the same effect as in the embodiment can be obtained.

[0025] Alternatively, as shown in shape example 4, a gradient may be provided such that the distance between the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 becomes narrower as the distance increases from the inlet 12. In this case, the gradient may be a flat gradient, a curved gradient, or a stepped gradient as shown in the other shape examples, provided on at least one of the inner peripheral side wall surface 10 or the outer peripheral side wall surface 11. With such a configuration, the same effect as in the embodiment can be obtained.

[0026] Alternatively, as shown in Shape Example 5, a configuration can be adopted in which the flow paths 9 having the shapes exemplified in the embodiment and Shape Examples 1 to 4 are provided in individual areas partitioned by the partition portion 14. In other words, a configuration can be adopted in which a gradient is provided based on the positional relationship with the end of the flow path 9 and the inlet 12, etc., with each area being used as a reference, rather than based on the width (W1) of the flow path 9. Of course, the individual gradients can also be configured to be planar gradients, curved gradients, or stepped gradients on at least one of the inner peripheral wall surface 10 and the outer peripheral wall surface 11. With such a configuration, the same effects as those of the embodiment can be obtained.

[0027] Furthermore, as shown in FIG. 5 as a schematic diagram of a cross section perpendicular to the central axis (J) and an expanded view of the range X3-X4 in the schematic diagram expanded in the circumferential direction, a gradient can be provided such that the distance between the inner peripheral side wall surface 10 and the outer peripheral side wall surface 11 becomes narrower as the distance increases from the inlet 12 toward the outlet 13 in the circumferential direction.

[0028] 5 shows an example of a configuration in which the inner circumferential wall surface 10 has a flat gradient along the circumferential direction, but the gradient is not limited to a flat gradient, and may be a curved gradient or a stepped gradient. Also, at least one or both of the inner circumferential wall surface 10 and the outer circumferential wall surface 11 may have a gradient. With such a configuration, the same effect as the embodiment can be obtained. The dashed arrows in the flow path 9 indicate the flow of the refrigerant.

[0029] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0030] In the drawings, 1 indicates a rotating electric machine, 2 indicates a frame, 2a indicates a wall portion, 4 indicates a stator, 6 indicates a rotor, 9 indicates a flow path, 10 indicates an inner peripheral wall surface, 11 indicates an outer peripheral wall surface, 12 indicates an inlet, and 13 indicates an outlet.

Claims

1. A frame that houses a rotor and a stator, the frame is provided with a flow path through which a coolant flows, the flow path being formed in a wall portion, an inlet through which the coolant flows into the flow path, and an outlet through which the coolant flows out of the flow path, The flow passage has an inner circumferential wall surface and an outer circumferential wall surface that define the flow passage, and at least one of these surfaces is provided with a gradient.

2. The rotating electric machine according to claim 1 , wherein the flow passage has a gradient such that the inner peripheral side wall surface or the outer peripheral side wall surface is inclined with respect to the axial direction in a cross section passing through a central axis.

3. 2. The rotating electric machine according to claim 1, wherein the flow passage has a gradient such that a distance between the inner peripheral side wall surface and the outer peripheral side wall surface at the ends in the axial direction is relatively narrow in a cross section passing through a central axis.

4. 2. The rotating electric machine according to claim 1, wherein the flow passage has a gradient in which a distance between the inner peripheral side wall surface and the outer peripheral side wall surface changes continuously or stepwise.

5. 2. The rotating electric machine according to claim 1, wherein the flow passage is provided with a gradient such that a distance between the inner peripheral side wall surface and the outer peripheral side wall surface becomes narrower as the flow passage is farther away from the inlet.

6. 2. The rotating electric machine according to claim 1, wherein the flow passage has a gradient such that, in a cross-sectional view perpendicular to the central axis, the distance between the inner peripheral wall surface and the outer peripheral wall surface becomes narrower in the circumferential direction as the flow passage moves away from the inlet.

Images