stator
By setting non-magnetic end plates on the back of the stator core and on the teeth and tightening them axially, out-of-plane stress is generated, which solves the problem of increased iron loss caused by hot pressing and achieves the effect of suppressing iron loss.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2022-04-14
- Publication Date
- 2026-05-12
AI Technical Summary
In the stator core, which is divided into the back of the core and the teeth, the radial pressure caused by the hot pressing process generates in-plane stress, which leads to an increase in iron loss.
End plates are used to axially fasten and push the back of the core and the teeth, thereby generating out-of-plane stress to suppress iron loss. Specific measures include that the fastening surface of the end plate protrudes from the stator core and the axial length of the back of the core is longer than that of the teeth, and that end plates made of non-magnetic material are set at both ends of the stator core.
It effectively suppresses iron loss on the back of the core and on the teeth, and reduces the total iron loss of the stator core by applying pressure in the axial direction to generate out-of-plane stress.
Smart Images
Figure CN115250017B_ABST
Abstract
Description
[0001] This application claims priority to Japanese Patent Application No. 2021-075760, filed on April 28, 2021, which is incorporated herein by reference in its entirety, including the description, claims, drawings and abstract. Technical Field
[0002] This disclosure relates to a stator equipped with a stator core that is divided into a core back and teeth. Background Technology
[0003] The stator is the stationary part of a rotating electric motor, equipped with a stator core made of stacked steel plates and stator coils wound around the stator core. The stator core has an annular back yoke (back of the core) and teeth protruding from the inner circumference of the back yoke.
[0004] A segmented stator core (segmented core) is constructed, for example, by being divided into a back yoke and teeth. Japanese Patent Application Publication No. 2019-068567 discloses a segmented core in which multiple recesses are provided along the inner circumference of an annular back yoke, and the base ends of the teeth are fitted into the recesses of the back yoke. Summary of the Invention
[0005] However, the stator core is fixed to the housing of the rotating electric machine by hot pressing. At this time, the radial pressure generated by the pressing is applied to the stator core, generating in-plane stress in the stator core, which increases the iron loss of the stator core.
[0006] In the stator core that is divided into the back of the core and the teeth, when it is fixed to the shell by pressing, in-plane stress is generated on the back of the core and the teeth respectively, and the iron loss of the stator core increases.
[0007] Therefore, this disclosure provides a stator capable of suppressing iron loss on the back of the core and on each of the teeth in a stator core that is divided into a core back and teeth.
[0008] Methods for solving problems
[0009] According to the stator disclosed herein, it is characterized by being equipped with: a stator core, the stator core being divided into an annular core back and teeth protruding from the inner circumferential side of the core back; and an end plate, the end plate being axially fastened to and pressing against the core back and teeth.
[0010] In the stator according to this disclosure, preferably, the iron loss on the back of the core is greater than that on the teeth, and the surface of the end plate that fastens and pushes the back of the core protrudes from the surface of the end plate that fastens and pushes the teeth from the stator core.
[0011] In the stator according to this disclosure, preferably, the iron loss of the back of the core is greater than that of the teeth, and the axial length of the back of the core before being fastened and pushed by the end plate is longer than the axial length of the teeth before being fastened and pushed by the end plate.
[0012] The effects of the invention
[0013] According to the stator disclosed herein, out-of-plane stress can be generated on the back of the stator core and on each of the teeth, which are divided into a back of the core and teeth, and iron loss on the back of the core and on each of the teeth can be suppressed. Attached Figure Description
[0014] Figure 1 This is a schematic diagram showing a rotary electric motor according to an embodiment.
[0015] Figure 2 This is a perspective view of a stator as an example of an implementation method.
[0016] Figure 3 It is a chart showing the relationship between the in-plane and out-of-plane stresses of the stator core and the iron loss.
[0017] Figure 4A This is a perspective view of the stator as another example of an implementation method.
[0018] Figure 4B yes Figure 4A AA section diagram.
[0019] Figure 5A This is a perspective view of the stator as another example of an implementation method.
[0020] Figure 5B It means Figure 5A BB cross-sectional view. Detailed Implementation
[0021] The embodiments of this disclosure will now be described in detail. In the following description, specific shapes, materials, orientations, values, etc., are examples for ease of understanding of this disclosure and may be appropriately changed according to their uses, purposes, specifications, etc.
[0022] The following uses Figure 1 and Figure 2 The rotary motor 10 equipped with a stator 20 as an example of an implementation will be described. Figure 1 This is a schematic diagram showing the rotary motor 10. Figure 2 This is a perspective view showing the stator core 21 of the stator 20. The following description will focus on the circumferential and radial directions, with the rotation shaft 11 of the rotary electric machine 10 as the axial direction.
[0023] The rotary motor 10 is a device equipped with a stator 20 according to the present disclosure. The rotary motor 10 is installed in electric vehicles such as hybrid vehicles and electric vehicles. When powered, the rotary motor 10 functions as a motor using electricity supplied from a battery (not shown) to drive the wheels of the electric vehicle. When braking, it functions as a generator to recover regenerative energy and charge the battery.
[0024] The rotary motor 10 is equipped with: a rotating shaft 11; a rotor 12, which is a rotating component fixedly mounted on the rotating shaft 11; a stator 20, which is a fixed component that generates rotational torque through interaction with the rotor 12; a housing 13, which houses the rotating shaft 11, the rotor 12 and the stator 20; and a plurality of bolts 14, which fix the stator core 21, which will be described later, to the housing 13.
[0025] The rotor 12 is equipped with a plurality of permanent magnets (not shown in the figure). When a drive current is supplied to the stator coil 23, which will be described later, the rotor 12 rotates relative to the stator 20 by means of the electromagnetic force generated in the stator coil 23 by the supplied drive current.
[0026] As described above, the stator 20 generates rotational torque through interaction with the rotor 12. In the stator 20, iron loss of the stator core can be suppressed by using end plates 22 to fasten and press the back 25 of the stator core 21 and the axial ends of the teeth 26, which will be described in detail later.
[0027] The stator 20 includes: a stator core 21, which is constructed by stacking steel plates; an end plate 22 disposed on at least one end side of the stator core 21 in the axial direction (in this example, disposed on both ends); and a stator coil 23 wound in the slots of the stator core 21 (the circumferential gaps between the teeth 26, which will be described later).
[0028] like Figure 2 As shown, the stator core 21 is constructed by stacking thin steel plates as described above, and multiple slots are formed on the inner side, into which the stator coils 23 are inserted. The stator core 21 has a core back 25 forming an annular shape, and teeth 26 protruding from the inner circumferential side of the core back 25.
[0029] The stator core 21 is constructed by dividing it into a core back 25 and teeth 26. More specifically, in the stator core 21, a plurality of recesses 25A are formed along the inner circumference of the core back 25, and the base ends of the teeth 26 are fitted into the recesses 25A.
[0030] The end plate 22 is an annular plate made of non-magnetic material. The end plate 22 is disposed on both ends of the stator core 21 in the axial direction. In addition, the end plate 22 is disposed radially across the entire back 25 of the core and the teeth 26. The end plate 22 and the stator core 21 are fastened together to the housing 13 by bolts 14, which will be described later.
[0031] With the stator core 21 and end plate 22 fixed to the housing 13, the stator core 21 is secured and pressed by the end plate 22, and axial pressure is applied to the stacked stator core 21. In other words, the back 25 and teeth 26 of the core are secured and pressed by the end plate 22, and axial pressure is applied to the back 25 and teeth 26 of the core. As a result, out-of-plane stress is generated on the back 25 and teeth 26 of the core, which can suppress the iron loss of the stator core 21, which will be described in detail later.
[0032] Bolt 14 passes through the through hole of stator core 21 and through hole of end plate 22 and is threaded into housing 13 to fasten stator core 21, end plate 22 and housing 13, and fix stator core 21 and end plate 22 to housing 13.
[0033] The following uses Figure 3 Explain the relationship between the in-plane and out-of-plane stresses of the stator core 21 and the iron loss.
[0034] like Figure 3 As shown in the diagram (A), before the stator core 21 is fixed to the housing 13, the stator core 21 has iron loss caused by the material of the stator core 21.
[0035] When the stator core 21 is fixed to the housing 13, it is pressed in using methods such as hot pressing. At this time, due to the radial pressure applied to the stator core 21, in-plane stress is generated. Here, in-plane stress refers to the stress generated within the surface of the steel plate due to the radial pressure applied to it. For example... Figure 3 As shown in the graph (B), when in-plane stress is generated in the stator core 21, the iron loss of the stator core 21 increases.
[0036] However, as Figure 3 As shown in the diagram (C), when out-of-plane stress is generated in the stator core 21, iron loss is confirmed to be suppressed. Here, out-of-plane stress refers to the stress generated in the surface of the steel plate due to the applied pressure acting in the axial direction of the steel plate. Therefore, when in-plane stress is generated in the stator core 21, by applying an applied pressure in the axial direction to generate out-of-plane stress in the stator core 21, the iron loss of the stator core 21 can be suppressed.
[0037] In this example, in the stator core 21 divided into a core back 25 and teeth 26, with the stator core 21 and end plate 22 fixed to the housing 13, the core back 25 and teeth 26 are secured and pressed by the end plate 22, and axial pressure is applied to the core back 25 and teeth 26. This generates out-of-plane stress in the core back 25 and end plate 26, which can suppress the iron loss of each core back 25 and tooth 26. As a result, the iron loss of the stator core 21 can be suppressed.
[0038] The following describes an example where the back 25 and teeth 26 of the stator core 21 are constructed from different materials, resulting in different iron losses for the back 25 and teeth 26. More specifically, the stator core 21 is configured such that the iron loss of the back 25 is greater than that of the teeth 26. In this example, an electromagnetic steel sheet is preferably used as the steel plate constituting the back 25. Furthermore, an amorphous metal or a nanocrystalline material is preferably used as the steel plate constituting the teeth 26.
[0039] Furthermore, the following describes an example in which, in the stator core 21 that is divided into a core back 25 and a tooth 26 as described above, the iron loss suppression amount of the core back 25 is greater than that of the tooth 26 when the iron loss of the core back 25 is greater than that of the tooth 26 as described above.
[0040] use Figure 4A and Figure 4B The stator, which is another example of an implementation method, will be described in detail. Figure 4A This is a three-dimensional diagram representing the stator core 31. Figure 4B yes Figure 4A AA section diagram.
[0041] As described above, the stator has a stator core 31 formed by stacking steel plates, and end plates 32 provided on both ends of the stator core 31 in the axial direction. In addition, as described above, the stator core 31 is divided into a core back 35 and teeth 36.
[0042] The end plate 32 is formed such that the surface of the end plate 32 facing the stator core 31 is formed by a step consisting of a facing surface 32A that fastens and pushes the back of the core 35 and a facing surface 32B that fastens and pushes the teeth 26. The facing surface 32A protrudes towards the stator core 31 more than the facing surface 32B.
[0043] As described above, the stator core 31, end plate 32, and housing 13 are fastened together using bolts 14 (see reference). Figure 1 When the end plate 32 applies a tightening pressure on the stator core 31 in the axial direction, the compression of the back 35 of the core becomes greater than the compression of the tooth 36, and the out-of-plane stress generated on the back 35 of the core becomes greater than the out-of-plane stress generated on the tooth 26.
[0044] In addition, Figure 4A and Figure 4B In the image, the steps of the opposite surfaces 32A and 32B of the end plate 32 are shown in extreme magnification, as are the steps of the back of the core 35 and the tooth 36 formed by being fastened and pressed.
[0045] At this point, as described above, since the iron loss on the back side 35 of the core is greater than that on the tooth 36, by generating an out-of-plane stress on the back side 35 of the core that is greater than that on the tooth 36, an out-of-plane stress corresponding to the magnitude of the iron loss is generated, and the iron loss can be suppressed according to the magnitude of the iron loss.
[0046] In this way, by forming the opposite surface 32A of the core back 35 that fastens and pushes the end plate 32 protruding towards the stator core 31 from the opposite surface 32B of the teeth 36 that fasten and push the end plate 32, the iron loss of the core back 35, which is larger than that of the teeth 36, can be suppressed more effectively than that of the teeth 36.
[0047] The following uses Figure 5A and Figure 5B The stator is described in detail as another example of an implementation method. Figure 5A This is a three-dimensional diagram representing the stator core 41. Figure 5B yes Figure 5A BB cross-sectional view.
[0048] Similar to the embodiment described above, the stator has a stator core 41 formed by stacking steel plates and end plates (not shown in the figure) provided on both ends of the stator core 41 in the axial direction. In addition, as described above, the stator core 41 is formed by dividing it into a core back 45 and teeth 46.
[0049] In the stator core 41, before it is fixed to the housing 13, that is, before it is fastened and pressed by the end plate, the axial length (height H1) of the back 45 of the core is longer than the axial length (height H2) of the teeth 46 before they are fastened and pressed by the end plate.
[0050] As described above, the sub-core 41, end plate, and housing 13 are fastened together using bolts 14 (see reference). Figure 1 When the end plate applies pressure in the axial direction of the stator core 41, the compression of the back 45 of the core becomes greater than that of the tooth 46, and the out-of-plane stress generated on the back 45 of the core becomes greater than that generated on the tooth 46.
[0051] At this point, as described above, since the iron loss on the back side 45 of the core is greater than that on the tooth 36, by generating an out-of-plane stress on the back side 45 of the core that is greater than that on the tooth 46, an out-of-plane stress corresponding to the magnitude of the iron loss can be generated, and the iron loss can be suppressed according to the magnitude of the iron loss.
[0052] In this way, by making the axial length of the core back 45 before the end plate is tightened and pushed longer than the axial length of the tooth 46 before the end plate is tightened and pushed, the iron loss of the core back 45, which has a greater iron loss than that of the tooth 46, can be suppressed more than that of the tooth 46.
[0053] In addition, Figure 5A and Figure 5B The image shows, in an extremely magnified manner, the height difference between the back of the core 45 and the tooth 46 before it was tightened and pressed.
[0054] Furthermore, it goes without saying that the present invention is not limited to the above-described embodiments and their variations, and various changes or improvements can be made within the scope of the claims of this application.
Claims
1. A stator, wherein, Equipped with: A stator core, the stator core being divided into an annular core back and teeth protruding from the inner circumferential side of the core back; and End plate, which axially fastens and presses against the back of the core and the teeth. The iron loss on the back of the core is greater than the iron loss of the teeth. The end plate is formed such that the surface of the end plate facing the stator core consists of a step formed by a face that fastens and presses against the back of the core and a face that fastens and presses against the teeth. The face of the end plate that fastens and presses against the back of the core protrudes from the face of the end plate that fastens and presses against the teeth from the stator core. With this configuration, when the end plate applies a fastening force to the stator core in the axial direction, the compression of the back of the core becomes greater than the compression of the teeth.