Motor case
The motor case design with meandering oil passages addresses the limitations of narrow gaps by promoting turbulent lubricating oil flow for improved heat transfer, simplifying the structure and reducing size.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-10-19
- Publication Date
- 2026-07-22
AI Technical Summary
Existing motor cases with narrow gaps for lubricating oil passages limit the flow rate and promote laminar flow, restricting heat transfer from the motor to the case.
The motor case design incorporates wedge-shaped and corrugated portions that form a meandering oil passage, allowing lubricating oil to flow in both radial and circumferential directions, promoting turbulence and increasing the wetted area for enhanced heat transfer.
The meandering oil passage disrupts lubricating oil flow, enhancing heat transfer from the stator to the motor case, reducing the need for additional cooling structures and enabling miniaturization.
Smart Images
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Abstract
Description
Technical Field
[0006] , , , , ,
[0001] The present disclosure relates to a motor case.
Background Art
[0002] Patent Document 1 discloses a configuration in which a gap is formed between the inner peripheral surface of a motor case and the outer peripheral surface of a stator core, and the motor is cooled by flowing lubricating oil through the gap.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the configuration disclosed in Patent Document 1, since the gap serving as the oil passage is thin and narrow, the flow rate of the lubricating oil is limited. Further, in the configuration disclosed in Patent Document 1, since the flow path of the lubricating oil in the oil passage becomes a laminar flow with little turbulence, the heat transfer from the motor to the motor case is limited, and there is room for improvement.
[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a motor case capable of promoting heat transfer from a motor to a motor case.
Means for Solving the Problems
[0006] The motor case according to this disclosure comprises an inner wall of the case and an oil passage provided in the inner wall of the case through which lubricating oil flows, wherein the inner wall of the case comprises a plurality of wedge-shaped portions arranged in the circumferential direction of the stator and supporting the outer circumference of the stator, and a corrugated portion arranged radially outward of the stator relative to the plurality of wedge-shaped portions and arranged around the plurality of wedge-shaped portions, wherein the oil passage is provided between the plurality of wedge-shaped portions and the corrugated portion and meanders so that the lubricating oil flows in the radial and circumferential directions of the stator. [Effects of the Invention]
[0007] According to this disclosure, the meandering of the oil passage disrupts and agitates the flow of lubricating oil within the passage, thereby promoting heat transfer from the motor to the motor case. [Brief explanation of the drawing]
[0008] [Figure 1] Figure 1 is a cross-sectional view showing the configuration of a motor case according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view showing a modified configuration of the motor case according to the embodiment. [Modes for carrying out the invention]
[0009] A motor case according to the embodiments of this disclosure will be described with reference to the drawings. Note that some of the components in the embodiments described below are substituted or substantially identical to those that are easily substituted by a person skilled in the art.
[0010] The motor case according to this embodiment is for housing a motor consisting of a stator and a rotor. The motor case according to this embodiment is formed, for example, from aluminum die casting. Furthermore, as described later, the motor case according to this embodiment contains lubricating oil that comes into direct contact with the motor (stator).
[0011] As shown in Figure 1, the motor case 1 comprises an inner wall 11 and an oil passage 12. For the sake of explanation, the figure shows only a portion of a cross-section of the cylindrical motor case 1 and cylindrical stator 2, cut at a predetermined position in the axial direction.
[0012] The inner wall 11 of the case comprises a plurality of wedge-shaped portions 111 and a corrugated portion 112. The plurality of wedge-shaped portions 111 and corrugated portions 112 are integrally constructed. That is, as shown in Figure 1, the plurality of wedge-shaped portions 111 and corrugated portions 112 are spaced apart at predetermined positions in the axial direction of the stator 2, but are connected at, for example, both ends (or one end) in the axial direction of the stator 2. However, the plurality of wedge-shaped portions 111 and corrugated portions 112 may each be constructed as separate parts.
[0013] Multiple wedge-shaped portions 111 are arranged on the outer circumference of the cylindrical stator 2. That is, the multiple wedge-shaped portions 111 are arranged in a line in the circumferential direction of the stator 2. Furthermore, the multiple wedge-shaped portions 111 are arranged at predetermined intervals in the circumferential direction of the stator 2. In addition, the tips of the multiple wedge-shaped portions 111 abut against the outer circumference of the stator 2 and support the outer circumference of the stator 2. Although not shown in Figure 1, the stator 2 is also fixed by fastening members (bolts, etc.) not shown.
[0014] The corrugated portion 112 is positioned radially outward from the stator 2 relative to the multiple wedge-shaped portions 111. Furthermore, the corrugated portion 112 is positioned around the stator 2 and the multiple wedge-shaped portions 111.
[0015] The oil passage 12 is a flow path for lubricating oil. This oil passage 12 is provided as a whole in the circumferential direction of the stator 2. That is, the lubricating oil in the oil passage 12 as a whole flows in the circumferential direction of the stator 2.
[0016] Furthermore, the oil passage 12 is provided between the multiple wedge-shaped sections 111 and the corrugated section 112. That is, the oil passage 12 consists of a space partitioned by the surfaces of the multiple wedge-shaped sections 111, the outer circumferential surface of the stator 2 between each wedge-shaped section 111 (see section A in Figure 1), and the surface of the corrugated section 112.
[0017] Furthermore, as shown in section B of Figure 1, the oil passage 12 meanders so that the lubricating oil flows in both the radial and circumferential directions of the stator 2. In other words, when the oil passage 12 is cut at a predetermined position in the axial direction of the stator 2 as shown in the figure, spaces extending radially (radially outward and radially inward) and spaces extending circumferentially are alternately connected. In other words, the oil passage 12 is formed in a labyrinth (wave-shaped) or zigzag shape. As a result, the lubricating oil in the oil passage 12 flows alternately in the radial and circumferential directions, as shown in section B of the figure.
[0018] In a typical motor case, the outer circumference of the stator is supported by, for example, a cylindrical inner wall of the case, and the inner wall of the case and the outer circumference of the stator are in close contact. On the other hand, in the motor case according to this embodiment, the stator 2 is supported by the tips of a plurality of wedge-shaped portions 111, so that, as shown in part A of Figure 1, the lubricating oil comes into direct contact with the stator 2 between each wedge-shaped portion 111, and the area in direct contact with the lubricating oil (wetted area) of the stator 2 increases. This promotes heat transfer from the stator 2 to the motor case 1.
[0019] Furthermore, in the motor case according to this embodiment, the stator 2 is supported by the tips of the multiple wedge-shaped parts 111, eliminating the need for a separate stator holder or the like.
[0020] Furthermore, in typical motor cases, the oil passages are such that the lubricating oil flows only in the circumferential direction, thus limiting heat transfer from the stator to the motor case. In contrast, in the motor case according to this embodiment, the lubricating oil flows alternately in the radial and circumferential directions within the oil passage 12, colliding with the side surface of the wedge-shaped portion 111, the outer circumference of the stator 2, and the surface of the corrugated portion 112. This promotes heat transfer from the stator 2 to the motor case 1.
[0021] In addition, in the motor case according to the embodiment, due to the large surface area of the corrugated portion 112, heat transfer between the lubricating oil and the inner wall 11 of the case is promoted, so heat transfer from the stator 2 to the inner wall 11 of the case and air cooling via the motor case 1 are also promoted.
[0022] (Modification example) A modification example of the motor case according to the embodiment of the present disclosure will be described while referring to FIG. 2. The motor case 1A according to this modification example includes a case inner wall 11, an oil passage 12, and a plurality of air cooling fins 13. Since the configurations of the case inner wall 11 and the oil passage 12 are the same as those of the motor case 1 (see FIG. 1) described above, the description thereof will be omitted.
[0023] The plurality of air cooling fins 13 are provided on the outer periphery of the motor case 1A. That is, the plurality of air cooling fins 13 are provided side by side in the circumferential direction of the stator 2. Further, the plurality of air cooling fins 13 are provided at a predetermined interval in the circumferential direction of the stator 2.
[0024] Thus, in the motor case 1A, by providing the plurality of air cooling fins 13, air cooling via the motor case 1A is further promoted.
[0025] According to the motor case according to the embodiment described above, since the oil passage 12 meanders, the flow of the lubricating oil is disturbed and agitated in the oil passage 12, so heat transfer from the motor (stator 2) to the motor case 1 can be promoted.
[0026] In addition, in the motor case according to the embodiment, an oil passage 12 having a wide gap is provided between the wedge-shaped portion 111 and the corrugated portion 112, and the lubricating oil is caused to flow at a large flow rate and high speed. As a result, a high-speed flow with strong turbulence directly collides with the outer periphery of the stator 2 (see part A in FIG. 1) that forms part of the oil passage 12, and heat transfer from the stator 2 to the motor case 1 is promoted.
[0027] Furthermore, in the motor case according to this embodiment, the lubricating oil, which has become hot after receiving heat from the motor (stator 2), is sent to the outside of the motor case 1 and cooled, for example, by an external oil cooler (water-cooled or air-cooled). As a result, a water jacket around the motor case 1 is unnecessary, which simplifies the structure and allows for miniaturization and cost reduction.
[0028] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols]
[0029] 1.1A Motor Case 11 Case inner wall 111 Wedge-shaped part 112 Wave part 12 Oil road 13 cooling fins 2 staters
Claims
[Claim 1] The inner wall of the case and An oil passage is provided in the inner wall of the case through which lubricating oil flows, Equipped with, The inner wall of the case is A plurality of wedge-shaped parts are arranged in a line in the circumferential direction of the stator and support the outer circumference of the stator, With respect to the plurality of wedge-shaped portions, a corrugated portion is arranged radially outward of the stator and around the plurality of wedge-shaped portions, Equipped with, The oil passage is provided between the plurality of wedge-shaped sections and the corrugated section, and is meandering so that the lubricating oil flows in the radial and circumferential directions of the stator. Of the outer circumference of the stator, the portion not supported by the plurality of wedge-shaped portions is exposed to the oil passage and comes into contact with the lubricating oil. Motor case.