Embedded member for rotating electric machine

Abstract

The utility model relates to an insert member for a rotating electrical machine. The present disclosure provides an insert member capable of satisfactorily controlling thermal conductivity. The present disclosure is a substantially cylindrical insert member to be cast into an aluminum alloy motor housing of a rotating electrical machine, in which a plurality of concavo-convex portions are formed on the outer peripheral surface of the insert member, the outer peripheral surface length ratio, which is the value obtained by dividing the length of a contour line by a predetermined axial length, is 1.15 or more, where the contour line is a line along the contour of the outer peripheral surface including the contour of the plurality of concavo-convex sections within the predetermined axial length range in the one cut surface. The one cut surface appears when the insert member is cut into two parts in the axial direction by an imaginary plane including the central axis of the insert member.

Description

Technical Field

[0001] The utility model relates to an embedded component for a rotating motor. Background Art

[0002] Generally speaking, aluminum alloys are often used as structural members for the motor housing of rotating electrical machines. Furthermore, in the portion of the motor housing where the stator is located, a high-strength, substantially cylindrical member made of an iron-based material is sometimes used as an insert member to enhance strength. In this regard, proposals have been made to provide recessed and raised portions on the outer circumference of the insert member, which is to be integrated with the motor housing by press-fitting or casting (see, for example, Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-169500

[0006] Patent Document 2: Japanese Patent Application No. 6655560

[0007] However, compared to the aluminum alloys commonly used as structural members of motor housings, inserts made of iron-based materials have poor thermal conductivity. Therefore, while the recessed and raised surfaces on the outer circumference of the insert can improve the bonding strength with the motor housing, they also prevent the efficient dissipation of heat generated by heat-generating elements such as the stator. This can lead to a decrease in motor output power and a reduction in the magnetic force of the motor's magnets. Utility Model Content

[0008] The technology of the present invention has been accomplished in view of the above-mentioned circumstances, and an object of the present invention is to provide an embedment member capable of satisfactorily controlling the thermal conductivity at the interface between the embedment member and the motor housing.

[0009] To solve the above-mentioned problems, the present invention employs the following configuration. One aspect of the present invention is an insert component for a rotating electrical machine, which is a substantially cylindrical insert component to be cast into an aluminum alloy motor housing of the rotating electrical machine. The insert component includes a concave-convex portion formed on an outer peripheral surface of the insert component, the concave-convex portion including a concave portion and a convex portion. In a single cut plane, when a line along the contour of the outer peripheral surface including the contour of the concave-convex portion within a predetermined axial length is defined as a contour line, an outer peripheral surface length ratio, which is a value obtained by dividing the length of the contour line by the predetermined axial length, is 1.15 or greater. The single cut plane is one of the cut planes that appear on either side of the central axis of the insert component when the insert component is bisected axially by an imaginary plane containing the central axis of the insert component.

[0010] In addition, it is also possible that the embedded component is divided into a solid part area and a non-solid part area within the range of the specified axial length, the solid part area being an area where the embedded component overlaps with the line segment on the line segment when a line segment parallel to the inner circumferential surface of the embedded component overlaps with the one cutting surface, and the non-solid part area is an area where the embedded component does not overlap with the line segment on the line segment when a line segment parallel to the inner circumferential surface of the embedded component overlaps with the one cutting surface, and the value representing the proportion of the solid part area on the line segment within the range of the specified axial length is set as the solid part ratio, and the line segment is moved from the top end of the convex part that protrudes most among the concave-convex parts toward the base end side of the convex part in the height direction of the concave-convex part at a specified interval within the one cutting surface in the embedded component to obtain each measuring point, and the points where each measuring point is marked in sequence are marked The value of the solid part ratio is represented by the solid part ratio on the horizontal axis and the distance from the top end in the height direction on the vertical axis as the measured height, which is set as a solid part total graph, the average of the solid part ratios at the measurement points based on multiple cutting surfaces is set as an average solid part ratio, the solid part total graph on which the average solid part ratios are sequentially plotted is set as an average solid part total graph, in which the position where the average solid part ratio is 0 is set as the top end on the graph, the position where the average solid part ratio first exceeds 0.98 when sequentially plotted from the top end side toward the base end side is set as the base end on the graph, and when the distance from the top end on the graph to the base end on the graph is set as the average maximum height of the concave-convex portion, the average maximum height of the concave-convex portion is greater than 0.15 mm and less than 1.50 mm.

[0011] In addition, it is also possible that when the average solid portion ratio at the position after the height is moved 0.10 mm from the base end portion in the figure to the top end portion side in the figure is set to A, and the value obtained by dividing the outer peripheral surface length ratio by A is set as the first interface parameter, the first interface parameter is greater than 1.30.

[0012] Furthermore, when the thickness of the insert member is half of a value obtained by subtracting an inner diameter from an outer diameter of the insert member, the thickness of the insert member may be equal to or greater than 0.8% of the outer diameter of the insert member.

[0013] The outer peripheral surface may be subjected to a surface roughening treatment.

[0014] Furthermore, the outer peripheral surface of the insert member may have at least one of a region where the outer peripheral surface length ratio is less than 1.15 and a region where the first interface parameter is less than 1.30 in a portion in the axial direction.

[0015] In addition, in the average solid part total graph, the value obtained by subtracting the average solid part ratio at a certain measured height from the average solid part ratio at the base end portion on the graph is set as the average non-solid part ratio, and the average non-solid part ratio at the position after the height is moved 0.10 mm from the base end portion on the graph to the top end portion side on the graph is set as B, and 0.10 / B≤1.30.

[0016] In addition, it may also be that, in the average solid part total graph, the value obtained by subtracting the average solid part ratio at a certain measured height from the average solid part ratio at the base end portion on the graph is set as the average non-solid part ratio, and the average non-solid part ratio at the position after the height is moved 0.10 mm from the base end portion on the graph to the top end portion side on the graph is set as B, 0.10×B≥0.01.

[0017] Furthermore, in the average substantial portion total graph, the height from the base end portion on the graph to the position where the average substantial portion ratio is 0.30 may be 0.40 mm or less.

[0018] Furthermore, in the average substantial portion total diagram, the second interface parameter, which is a value obtained by dividing the outer peripheral surface length ratio by the height from the base end portion on the diagram to the position where the average substantial portion ratio is 0.30, may be 4.00 or greater.

[0019] Utility model effect

[0020] According to the present invention, an embedding component capable of well controlling the thermal conductivity at the interface between the embedding component and the motor housing can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an overall view of an insert member for a rotating electrical machine according to an embodiment and an enlarged view of a portion of an outer peripheral surface of the insert member for a rotating electrical machine.

[0022] Figure 2 This is a cross-sectional view showing an example of a predetermined cut surface of the insert member for the rotating electrical machine according to the embodiment.

[0023] Figure 3 This is an average solid portion total graph illustrating the relationship between the measured height and the average solid portion ratio of the insert member for the rotating electrical machine according to the embodiment.

[0024] Description of Reference Numerals

[0025] 1: Embedded components for rotating motors;

[0026] 10: convex part;

[0027] 13: concave part;

[0028] 20: line segment;

[0029] 30: contour line;

[0030] 40: inner circumference;

[0031] C: The center axis of the embedded component. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention with reference to the accompanying drawings. Unless otherwise specified, the configurations described in the following embodiments are not intended to limit the technical scope of the present invention to these configurations. The configurations and combinations thereof in the following embodiments are merely examples, and additions, omissions, substitutions, and other modifications may be made as appropriate without departing from the spirit of the present invention.

[0033] <Implementation Method>

[0034] [structure]

[0035] Figure 1 This figure shows an overall view of an insert component 1 for a rotating electrical machine (hereinafter referred to as "insert component 1") according to an embodiment, as well as an enlarged view of a portion of the outer peripheral surface of the insert component 1. In this embodiment, the direction along the central axis C of the insert component 1 is referred to as the axial direction, and the direction perpendicular to the axial direction and extending from the central axis C toward the outer peripheral surface of the insert component 1 is referred to as the radial direction. Furthermore, the direction around the central axis C along the outer peripheral surface of the insert component 1 is referred to as the circumferential direction. These axial, radial, and circumferential directions are merely directions used to indicate the relative positional relationships of the various components in the insert component 1.

[0036] The insert member 1 of this embodiment is, for example, a cast iron member formed into a generally cylindrical shape centered on a central axis C, with multiple protrusions 10 formed on its outer circumferential surface. Herein, the portion recessed relative to the protrusions 10 is referred to as a "recess 13," and the structure including the protrusions 10 and the recesses 13 is referred to as a "recessed-convex portion." The rotary electric machine to which the present invention is applied is, for example, a rotary electric machine used in electric vehicles, etc. However, the rotary electric machine to which the present invention is applied is not limited thereto. In this embodiment, the outer diameter OD of the insert member 1 is formed within a range of 150 mm to 300 mm, but this can be appropriately changed depending on the intended use. The outer diameter OD is the value corresponding to the distance between two parallel planes when the insert member 1 is placed between them, with the top ends 11 of the protrusions 10 located on the outer circumferential surface of the insert member 1 in contact with each of the two parallel planes. The thickness of the insert member 1 is defined as half the value obtained by subtracting the inner diameter ID from the outer diameter OD. This thickness of the insert member 1 is preferably at least 0.8% of the outer diameter OD of the insert member 1. If the thickness of the insert member 1 is less than 0.8% of the outer diameter OD, the strength of the insert member 1 when integrated with the motor housing will be insufficient, increasing the risk of cracking the insert member 1. Furthermore, the insert member 1 is ideally lightweight, so the thickness of the insert member 1 is preferably less than approximately 4% of the outer diameter OD.

[0037] A rotating electric machine is constructed, for example, to include components such as a rotating shaft, a rotor, a stator, a motor housing, and bearings. The motor housing has a cylindrical portion formed by hollowing out the interior. The stator is generally formed of an electromagnetic steel plate or the like and is fitted into the inner circumference of the cylindrical portion. The embedded component 1 is arranged in the portion of the motor housing that is fitted with the stator. Here, the embedded component 1 is cast into the inner circumference of the motor housing made of an aluminum alloy and used. As a result, the motor housing and the embedded component 1 form a composite structure in which at least a portion of the outer circumference of the embedded component 1 is covered with aluminum alloy. Here, the stator fitted into the inner circumference of the embedded component 1 generates heat as the rotating electric machine operates. However, by setting the outer circumference of the embedded component 1 to an appropriate shape, the thermal conductivity at the interface between the embedded component 1 and the motor housing can be well controlled, and the generated heat can be efficiently discharged to the motor housing.

[0038] Regarding the material of the insert member 1, cast iron or the like having high thermal conductivity is more suitable than steel, but is not particularly limited. Typically, flake graphite cast iron such as a material corresponding to JIS FC250 can be used, taking thermal conductivity and workability into consideration.

[0039] The concavo-convex portions on the outer circumferential surface of the embedded component 1 can be formed by transferring the concavo-convex portions of the mold coating during centrifugal casting, directly machining the outer circumferential surface of the embedded component such as by cutting, performing a surface roughening treatment, or a combination of these methods. Examples of surface roughening treatments include spraying, cold spraying, and shot peening. Examples of spraying materials include aluminum alloys, but are not particularly limited. However, the material of the embedded component 1 and the method for forming the concavo-convex portions are merely examples and are not particularly limited.

[0040] Figure 2 This is a cross-sectional view showing an example of a predetermined cutting surface of the embedded component 1 of the embodiment. The predetermined cutting surface in this embodiment is a cutting surface that appears one of the cutting surfaces on both sides of the center axis C when the embedded component 1 is cut in two along the axial direction using an imaginary plane including the center axis C of the embedded component 1. The axial length of one cutting surface is greater than or equal to the length d1 described later. Figure 2 As an example of a prescribed cutting surface, the figure shows Figure 1 The A-A' section of Figure 2 , the concavo-convex portion included in the insert member 1 of this embodiment will be described.

[0041] The convex portion 10 of the concave-convex portion is a portion of the embedded component 1 and is formed on the outer peripheral surface of the embedded component 1. Multiple convex portions 10 may be arranged in the axial and circumferential directions with their positions and density being discontinuous and irregular (random), or they may be arranged in the axial and circumferential directions with their positions and density being continuous and regular. Furthermore, the convex portion 10 has a tip portion 11 and a base portion 12, and is formed so as to protrude radially outward from the base portion 12 toward the tip portion 11 toward the embedded component 1. However, the shapes of the convex portion 10 and the concave portion 13 are not particularly limited.

[0042] Furthermore, the plurality of projections 10 may be formed on a portion of the outer peripheral surface of the insert member 1 or may be partially removed. Thus, the plurality of projections 10 may be formed only on a portion of the outer peripheral surface of the insert member 1.

[0043] The protrusion 10 is sometimes formed by centrifugal casting while being cast with centrifugal force. In this case, the top portion 11 of the protrusion 10 is formed with respect to the inner circumference of the mold. Therefore, if the inner circumference of the mold is a perfect circle, the distance between the top portion 11 and the center axis C of the embedded component 1 is approximately the same, while the distance between the base portion 12 and the center axis C may not be the same. Therefore, when using the solid portion total diagram described later to derive the average maximum height h1 of the concave and convex portions, the height of the protrusion 10 is measured with respect to the top portion 11. However, the method of forming the protrusion 10 is not limited to this. For example, it can also be formed by performing mechanical processing such as cutting on the outer circumference of the cylindrical component.

[0044] The shape of the protrusion 10 is not particularly limited. For example, the protrusion 10 may have a continuous spiral shape or a continuous ring shape along the circumferential direction. For example, the protrusion 10 may be formed into a spiral or ring shape by directly machining the outer circumference of the insert component 1, such as by cutting. The shape of the protrusion 10 may be any shape that is effective in the physical cutting test, thermal conductivity measurement, surface temperature simulation, and compactness evaluation described later.

[0045] Alternatively, the area where the concavo-convex portion is formed may be limited to a portion of the outer circumferential surface of the insert component 1. Furthermore, the outer circumferential surface of the insert component 1 may include at least one of a region with an outer circumferential surface length ratio less than 1.15 (described later) and a region with a first interface parameter less than 1.30 (described later) in an axial portion. In this case, the region with an outer circumferential surface length ratio less than 1.15 and a region with a first interface parameter less than 1.30 may or may not have concavo-convex portions. Furthermore, the axial length of the region with an outer circumferential surface length ratio less than 1.15 and a region with a first interface parameter less than 1.30 is preferably less than 50% of the total length of the insert component 1, more preferably less than 30%, and even more preferably less than 10% of the total length of the insert component 1. Furthermore, the region with an outer circumferential surface length ratio less than 1.15 and a region with a first interface parameter less than 1.30 on the outer circumferential surface of the insert component 1 may comprise either a portion of the circumferential area or the entire circumferential area. By limiting the area where the outer peripheral surface length ratio is less than 1.15 and the area where the first interface parameter is less than 1.30 to a part of the outer peripheral surface, the location where heat is easily transferred can be changed in the embedded component 1 according to the heat-generating part of the stator, thereby preventing deformation of the embedded component 1 and the motor housing caused by heat.

[0046] Figure 2The reference numeral 30 shows the outline of the outer peripheral surface of the embedded component 1 (hereinafter referred to as "outline 30") along the shape of the protrusion 10 and the recess 13 within the range of the length d1 (an example of the "prescribed axial length" in the present invention) in the prescribed cutting surface. In addition, the reference numeral 40 shows the inner peripheral surface of the embedded component 1 (hereinafter referred to as "inner peripheral surface 40"). The embedded component 1 is formed into a cylindrical shape, so Figure 2 In FIG, the inner peripheral surface 40 is formed as a straight line along the axial direction.

[0047] [Outer Surface Length Ratio]

[0048] The peripheral surface length ratio is the value obtained by dividing the length of the contour line 30 within the range of length d1 by the length d1. When the average maximum height h1 of the concave and convex portions is equal, the larger the peripheral surface length ratio, the better the thermal conductivity can be expected. In this case, the peripheral surface length ratio is preferably 1.15 or greater, and more preferably 1.30 or greater. Furthermore, the peripheral surface length ratio can be easily increased by increasing the average maximum height h1 of the concave and convex portions and increasing the length of the contour line 30. However, if the average maximum height h1 of the concave and convex portions is too large, the volume occupied by the embedded component 1 near the interface between the embedded component 1 and the motor housing increases, resulting in increased thermal resistance and potentially impairing thermal conductivity at this interface. Therefore, it is preferable to set the peripheral surface length ratio to 3.00 or less. By setting the peripheral surface length ratio within this range, the average maximum height h1 of the concave and convex portions is not excessively large, thereby achieving excellent thermal conductivity at the interface between the embedded component 1 and the motor housing. Furthermore, the average maximum height h1 of the concave and convex portions is not too small, thereby preventing separation of the embedded component 1 from the motor housing. In one insert member 1 , the outer peripheral surface length ratio is measured at a plurality of cut surfaces, specifically, at six cut surfaces, and the outer peripheral surface length ratio is the average value thereof.

[0049] [Entity Ratio]

[0050] The convex portion 10 of the embedded component 1 is divided into a solid portion area 21 and a non-solid portion area 22. Figure 2 As shown, the solid portion region 21 and the non-solid portion region 22 are determined based on whether or not a line segment 20 having a length d1 overlaps with the convex portion 10 when the line segment 20 is aligned with the predetermined cutting plane. More specifically, within the range of length d1, the region where the line segment 20 overlaps with the convex portion 10 is defined as the solid portion region 21, and the region where the line segment 20 does not overlap with the convex portion 10 is defined as the non-solid portion region 22. It should be noted that the line segment 20 is a hypothetical line segment parallel to the inner circumferential surface 40 (that is, parallel to the central axis C) within the predetermined cutting plane and is provided to facilitate the identification of the solid portion region 21 and the non-solid portion region 22.

[0051] The solid portion ratio is a value indicating the ratio of the solid portion region 21 formed within the range of the length d1. Figure 2 By moving in the direction of arrow A20 (radially from the tip 11 side to the base 12 side) at a predetermined interval, the length of the solid portion area 21 at the measurement height of each measurement point in the measurement height can be obtained, wherein the measurement height is the radial distance from the tip 11. At this time, the ratio of the length obtained by summing the lengths of the solid portion area 21 at any measurement height to the length d1 is called the "solid portion ratio". The same operation is performed on multiple predetermined cutting surfaces, and the solid portion ratios of the protrusions 10 in each cutting surface are summarized. The solid portion ratios at the measurement height of each measurement point are averaged, thereby obtaining the average value of the solid portion ratios of each measurement point based on multiple predetermined cutting surfaces at the arbitrary measurement height, that is, the average solid portion ratio.

[0052] [Entity Department Total Chart]

[0053] like Figure 2 As shown, the line segment 20 is moved toward the base end 12 side of the embedded component 1 (the line segment 20 is moved in the direction of the arrow A20) at a predetermined interval, and the solid portion ratio is repeatedly obtained until the solid portion ratio reaches 1.00. The obtained solid portion ratio is plotted on a graph, thereby being able to be graphically represented as a shape obtained by summarizing the shapes of multiple protrusions 10 appearing in a predetermined cutting surface. This is called a "solid portion total graph". The solid portion total graph is a graph in which the distance from the top end 11 in the height direction of the concave and convex portion, that is, the measured height, is represented on the vertical axis and the solid portion ratio is represented on the horizontal axis. In addition, by performing the operation of calculating the solid portion ratio on multiple predetermined cutting surfaces and preparing an average solid portion total graph in which the average solid portion ratios calculated using multiple predetermined cutting surfaces are sequentially plotted, the formation state of the protrusion 10 in the embedded component 1 can be grasped on average. At this time, regardless of which predetermined cutting surface is used, the reference point in the height direction is set to "the most prominent convex portion 10 of the plurality of convex portions 10 within the range of length d1", and the spacing of the moving line segment 20 is also set to the same spacing. Thus, even in multiple predetermined cutting surfaces, the measured height can be uniquely determined. As an example of the embedded component 1 of this embodiment, Figure 3 The average solid portion total graph is shown in which average solid portion ratios that can be obtained intermittently from six predetermined cut surfaces of a certain sample are sequentially plotted with a predetermined pitch of 0.05 mm and a length d1 of 14.7 mm.

[0054] The average maximum height h1 of the concave and convex parts is the absolute value of the value from the top end of the figure to the base end of the figure on the vertical axis of the average solid part total graph. In the solid part total graph, the top end of the figure corresponds to "the top end 11 of the most protruding convex part 10 among the multiple convex parts 10 within the range of length d1". The measured height at the top end of the figure is 0 mm, and the solid part ratio is 0. In the solid part total graph, the base end of the figure is "the position where the solid part ratios plotted sequentially from the top end 11 side to the base end 12 side first exceed 0.98", and in the average solid part total graph, the base end of the figure is "the position where the average solid part ratios plotted sequentially from the top end 11 side to the base end 12 side first exceed 0.98". It should be noted that since the solid part ratios at each measuring point of the solid part total graph are measured from the top end 11 side of the convex part 10 located on the upper side toward the center axis C located on the lower side, the measured heights at each measuring point are expressed as negative values. The same applies to the averaged total solid area graph obtained from multiple total solid area graphs. However, the actual heights of the concave and convex portions and the average maximum height h1 of the concave and convex portions are the absolute values of the vertical axis on the averaged total solid area graph. The average maximum height h1 is the distance from the base end to the top end on the graph. Furthermore, the graph obtained by connecting the measurement points plotted on the averaged total solid area graph with a line is called the "average solid area curve."

[0055] The length d1 of the line segment 20 , which is the predetermined axial length, is set to 14.7 mm in principle, but may be appropriately changed in consideration of the sizes of the convex portion 10 and the concave portion 13 of the measurement sample.

[0056] [Measurement method]

[0057] [Preparation of measurement samples]

[0058] The following describes a method for measuring the length and solid portion ratio of the contour line 30. First, the method for adjusting the sample for measurement is described. Using a cross-section perpendicular to the axial direction, the embedded component 1, which includes the center axis C and has been cut in the axial direction, is further cut to a size that allows for resin embedding and polishing. The resin is then embedded in the sample, with the cut surface where the length and solid portion ratio of the contour line 30 are to be measured serving as the polished surface. After the resin has solidified, the sample is polished under running water using water-resistant sandpaper. The grit sizes of the water-resistant sandpaper are changed in the order of #220, #400, #800, #1000, and #1500. After polishing, the length and solid portion ratio of the contour line 30 are measured. The observation surface after polishing corresponds to the specified cut surface.

[0059] [Method for measuring the outer peripheral surface length ratio]

[0060] In this embodiment, a digital microscope RX-100 manufactured by Hirox Co., Ltd. was used to measure the length of the contour line 30. The objective lens magnification for measurement was set to 20x or 40x. For larger average maximum height h1 of the concave and convex portions, for example, when the average maximum height h1 of the concave and convex portions exceeds 0.30 mm, a 20x magnification was used. In the device used here, at a 20x objective lens magnification, the horizontal axis of the monitor measured 14.7 mm, which was designated as length d1. After placing the polished measurement sample, the inner circumferential surface 40 of the embedded component 1 was positioned parallel to the horizontal axis of the grid displayed on the observation monitor. The sample was then moved parallel to a position where the outer circumferential surface could be observed. Using the "Auto Area" tool in the microscope's software, by clicking on the embedded component 1 portion on the monitor and adjusting the grayscale density, the area and perimeter of the embedded component 1 portion can be automatically measured based on the grayscale density difference between the embedded component 1 and the embedding resin. At this time, the grayscale density is set to a value that prevents over- or under-selection of the embedded component 1. The measured circumference is the entire circumference of the embedded component 1 as viewed on the monitor. Therefore, the length corresponding to the portion of the embedded component 1 excluding the contour line 30 is calculated and subtracted from the measured length of the entire circumference. The length of the contour line 30 is thus calculated. The length of the portion excluding the contour line 30 can be calculated using the "Auto Width" tool included with the microscope. By dividing the thus-calculated length of the contour line 30 by the length d1, the outer circumference length ratio can be calculated.

[0061] [Measurement method of solid part ratio]

[0062] The solid portion ratio was measured using a digital microscope, RX-100, manufactured by Hirox Co., Ltd. The objective lens magnification used during measurement was 20x or 50x. For larger average heights h1 of the concave and convex portions, for example, when the average maximum height h1 of the concave and convex portions is 0.20 mm or greater, a 20x magnification was used. A grid and automatic width tool were used based on the software included with the microscope. The polished measurement sample was placed so that the inner circumferential surface 40 of the embedded component 1 was parallel to the horizontal axis of the grid displayed on the observation monitor. The observation sample was then moved parallel to a position where the outer circumferential surface could be observed. Next, the automatic width tool was used to measure the sample in the horizontal direction. Since the automatic width tool uses automatic grayscale density, the grayscale density was adjusted each time to appropriately identify the embedded component area corresponding to the solid portion 21 and the resin area corresponding to the non-solid portion 22. The sample was moved at a predetermined interval, and the length of the solid portion 21 at any measurement height was measured. In this embodiment, line segment 20 represents the measurement position of the automatic width tool. By moving line segment 20 radially from the tip 11 toward the base 12 at a predetermined interval, the axial length of the solid portion 21 at any measurement height relative to the tip 11 can be measured. Measurement is performed by moving line segment 20 from the tip 11 of the most protruding convex portion 10 within the length d1, toward the base 12, in increments of 0.05 mm or 0.025 mm. When using a 50x objective lens magnification, the predetermined interval is preferably 0.025 mm.

[0063] exist Figure 2 , the figure shows a case where the line segment 20 is located at position 20a and a case where the line segment 20 is located at position 20b. Position 20a is the position of the top end 11 of the protrusion 10 that protrudes most within the range of length d1. When the line segment 20 is located at the measurement height shown in position 20a, the line segment 20 overlaps with the top end 11 of the protrusion 10. Based on this, the line segment 20 is moved in the direction indicated by the arrow A20 (to the base end 12 side) at a prescribed interval. Position 20b is an example of a measurement height when the line segment 20 is repeatedly moved an arbitrary number of times by a prescribed interval. When the line segment 20 is located at the measurement height shown in position 20b, it can be said that the embedded component 1 is divided into a solid portion area 21 shown by a dotted line in the line segment 20 and a non-solid portion area 22 shown by a solid line in the line segment 20. The line segment 20 is moved along arrow A20, and the measurement is terminated when the line segment 20 is further moved along arrow A20 from the position where the solid portion ratio first exceeds 0.98, which will be described later, so that the entire line segment 20 within the length d1 is located in the solid portion area 21 (that is, when the solid portion ratio becomes 1.00).

[0064] [Non-physical ratio]

[0065] In the total of the real part chart, the non-real part ratio is used to make

[0066] [Non-solid portion ratio at any measurement height] = [Solid portion ratio at the base end portion in the figure] - [Solid portion ratio at any measurement height]

[0067] The value for which this relationship holds. In addition, in the average entity total graph,

[0068] [Average non-substantial ratio at any measurement height] = [Average substantial ratio at the base end portion in the figure] - [Average substantial ratio at any measurement height]

[0069] Such a relationship is established.

[0070] [Parameters of the average entity total graph]

[0071] Preferably, the convex portions 10 and concave portions 13 are formed so that the average maximum height h1 of the concave and convex portions in the average solid portion total diagram is within a range of 0.15 mm to 1.50 mm. More preferably, the average maximum height h1 of the concave and convex portions is within a range of 0.20 mm to 1.00 mm. Increasing the average maximum height h1 of the concave and convex portions can lengthen the length of the contour line 30. However, if the average maximum height h1 of the concave and convex portions is too large, the volume occupied by the convex portions 10 near the interface between the embedded component 1 and the motor housing increases, increasing the thermal resistance of conduction and potentially impairing thermal conductivity. In contrast, by setting the average maximum height h1 of the concave and convex portions to 1.50 mm or less while increasing the length of the contour line 30, that is, increasing the interface length ratio, improves thermal conductivity from the embedded component 1 to the motor housing and heat dissipation from the motor housing.

[0072] Furthermore, by setting the average maximum height h1 of the concave and convex portions to 1.50 mm or less, the embedded component 1 can be made lighter and more compact. However, if the average maximum height h1 of the concave and convex portions is too small, there is a risk that the bonding force between the embedded component 1 and the motor housing will be insufficient, causing the embedded component 1 to separate from the motor housing. Generally speaking, the greater the bonding force between the embedded component 1 and the motor housing, the better the thermal conductivity. Therefore, to maintain the bonding force between the embedded component 1 and the motor housing, it is preferable to set the average maximum height h1 of the concave and convex portions to 0.15 mm or more. This effectively prevents the embedded component 1 from separating from the motor housing.

[0073] In the average solid portion total graph, the average solid portion ratio at a position shifted 0.10 mm in height from the base end toward the top end is referred to as the "first average solid portion ratio," and the average non-solid portion ratio calculated based on the first average solid portion ratio is referred to as the "first average non-solid portion ratio." The value of the first average solid portion ratio is represented by A, and the value of the first average non-solid portion ratio is represented by B. For convenience, the value obtained by dividing the outer circumferential surface length ratio by A is referred to as the "first interface parameter." The first interface parameter helps understand the shape near the base end 12 of the protrusion 10. For example, a heat generating element, such as a stator, is positioned within the embedded component 1. In this case, heat generated by the heat generating element is transferred from the base end 12 of the protrusion 10 to the top end 11, where the motor housing or the like is positioned. Therefore, to efficiently transfer the heat from the heat generating element to the motor housing, it is preferable that the shape near the base end 12 of the embedded component 1 be as flat as possible. Therefore, the first average solid portion ratio is preferably as small as possible. In other words, the first interface parameter is preferably as large as possible. Figure 3 In FIG. 1 , the first average solid portion ratio at a position shifted by 0.10 mm in height from the base end portion in the figure toward the tip end portion in the figure is represented by A, and the first average non-solid portion ratio at the same position is represented by B.

[0074] For convenience, the value obtained by dividing the outer peripheral surface length ratio by the height from the base end portion to the position where the average solid portion ratio is 0.30 in the figure is referred to as the "second interface parameter". Figure 3 In the figure, "the height from the base end in the figure to the position where the average solid part ratio is 0.30" is represented as h2. In other words, height h2 is "the difference between the measured height of the base end in the figure and the measured height at the position where the average solid part ratio is 0.30." Here, if there are multiple positions with an average solid part ratio of 0.30, the position closest to the base end in the figure is set as the evaluation object. In other words, height h2 is the height from the base end in the figure to the position closest to the base end in the figure with an average solid part ratio of 0.30. The second interface parameter makes it easier to understand the shape of the protrusion 10 of the embedded component 1 from the base end in the figure to the position where the average solid part ratio is 0.30 based on the average solid part total diagram. By using the above-mentioned first and second interface parameters, the peripheral surface length ratio can be standardized at a certain position in the average solid part total diagram, making it easy to confirm the correlation between the shape of the concave and convex parts and thermal conductivity.

[0075] In the average solid area total graph, the measured height at a position where the average solid area ratio is 0.30 can be determined based on two consecutive points: a point with an average solid area ratio of less than 0.30 and a point with an average solid area ratio exceeding 0.30. Specifically, the measured height can be determined using a function connecting a point with an average solid area ratio of less than 0.30 and a point on the average solid area total graph that is continuous with the point and has an average solid area ratio exceeding 0.30.

[0076] By organizing the shapes of the concave and convex parts in the embedded component 1 of the present invention based on the outer peripheral surface length ratio and the average solid portion total diagram and using the first interface parameter and the second interface parameter, the embedded component 1 with better thermal conductivity at the interface between the embedded component 1 and the motor housing can be identified.

[0077] [Test / Simulation]

[0078] The embedded components 1 of Examples 1 to 11 of the present invention and the embedded components of Comparative Examples 1 to 3 were evaluated through testing and simulation using samples. Specifically, the embedded components of Examples and Comparative Examples (hereinafter referred to as Examples, etc.) were subjected to various parameter measurements, physical cutting tests, thermal conductivity measurements, and surface temperature simulations.

[0079] [Measurement of various parameters]

[0080] Various parameters of the embedded components of the examples were measured. Table 1 shows the results of each measurement item of the embedded components of the examples. In measurement item 1, the embedded components of each example were cut and the outer peripheral length ratio was calculated. In measurement items 2 to 8, the values were calculated using the average solid portion total graph of each example. When creating the average solid portion total graph of each example, the specified spacing was set to 0.05 mm or 0.025 mm. In addition, in the measurement of the outer peripheral length ratio, the specified axial length was set to 14.7 mm in Examples 1 to 3, Examples 6 to 11, and Comparative Examples 1 to 3, and the specified axial length was set to 7.35 mm in Examples 4 and 5. In addition, in the measurement of the average solid portion ratio, the specified axial length was set to 14.7 mm in Examples 1 to 3, Examples 6 to 11, Comparative Examples 1 and 3, and the specified axial length was set to 5.57 mm in Examples 4, 5, and Comparative Example 2. In addition, the units in parentheses in each measurement item are used, and the measurement items without parentheses are dimensionless numbers.

[0081] [1. Outer Surface Length Ratio]

[0082] As measurement item 1, the peripheral surface length ratio is measured. The embedded component in the examples, etc., is cut and polished along the axial direction using an imaginary plane containing the central axis C. The length of the contour line 30 is measured to determine the peripheral surface length ratio. Furthermore, to ensure that the required axial length of the contour line 30 is achieved, the embedded component is also cut in a direction perpendicular to the axial direction (radial direction). The cut surfaces thus obtained are observed under a microscope. Regarding the peripheral surface length ratio, six specified cut surfaces are randomly cut from one embedded component, and the average peripheral surface length ratio is determined.

[0083] [2. Average maximum height of concave and convex parts h1 (mm)]

[0084] As measurement item 2, the average maximum height h1 of the concave and convex portions was measured using the average solid portion total graph in each example, etc. Regarding Comparative Example 1, since the average maximum height h1 of the concave and convex portions was small, other measurements were not performed.

[0085] [3. First Average Solid Area Ratio A]

[0086] As measurement item 3, the first average solid portion ratio A was determined using the average solid portion total graph in each example, etc. As described above, the first average solid portion ratio A is the average solid portion ratio at a position shifted 0.10 mm in height from the base end portion on the graph toward the distal end portion on the graph.

[0087] [4. First interface parameters]

[0088] As measurement item 4, the first interface parameter was obtained by dividing the outer peripheral surface length ratio obtained in measurement item 1 by the first average solid portion ratio A obtained in measurement item 3.

[0089] [5.0.10 / first average non-solid portion ratio B (mm)]

[0090] As measurement item 5, the slope of the straight line connecting the measurement position of the first average solid portion ratio A and the base end on the graph in the average solid portion total graph of each embodiment is determined (hereinafter referred to as the slope of the average solid portion curve). In each embodiment, the first average non-solid portion ratio B is obtained by subtracting the value of the first average solid portion ratio A obtained in measurement item 3 from the average solid portion ratio of the base end on the graph. By confirming the slope of the average solid portion curve, it is helpful to understand the shape near the base end of the convex portion. The slope of the average solid portion curve is obtained by [0.10 / first average non-solid portion ratio B].

[0091] [6.0.10 × first average non-solid portion ratio B (mm)]

[0092] As measurement item 6, in the average solid portion total graph of each embodiment, the area of the specified region is calculated by the following. Similar to measurement item 5, in each embodiment, the first average non-solid portion ratio B is calculated by subtracting the first average solid portion ratio A calculated in measurement item 3 from the average solid portion ratio of the base end portion on the graph. Here, in the average solid portion total graph, the specified region is a rectangular region with a height of 0.10 mm relative to the base end portion on the graph and a width equal to the first average non-solid portion ratio B. It is an area including the average solid portion curve from the base end portion on the graph to the position after the height is moved 0.10 mm toward the top end portion on the graph. The area of the specified region is calculated by [0.10 × first average non-solid portion ratio B]. This helps to understand the shape of the concave and convex portion near the base end portion of the convex portion.

[0093] [7. Height h2 (mm) from the base end portion in the figure to the position where the average solid portion ratio is 0.30]

[0094] As measurement item 7, the height h2, which is the height from the base end in the figure to the position where the average solid portion ratio is 0.30, was determined for each example. The smaller the height h2, the closer the shape of the insert component from the base end in the figure to the position where the average solid portion ratio is 0.30 is to a flat shape.

[0095] 8. Second interface parameter (1 / mm)

[0096] As measurement item 8, the second interface parameter is obtained by dividing the outer peripheral surface length ratio obtained in measurement item 1 by the height h2 obtained in measurement item 7.

[0097] Table 1 shows the measurement results of various parameters measured as described above.

[0098] [Table 1]

[0099]

[0100] [Entity cutting test]

[0101] In the physical cutting test, in each embodiment, a composite body is produced in which an outer member is made of aluminum alloy and an embedded member is cast into the outer member. The outer member referred to here refers to a member located radially outside the embedded member, such as a motor housing. Furthermore, the composite body is cut to produce a 20 mm x 20 mm test piece. In each embodiment, the bonding between the embedded member and the outer member is evaluated by determining whether there is peeling between the embedded member and the outer member when the test piece is cut out multiple times. Specifically, six test pieces are cut out from each embodiment to determine whether there is peeling. The judgment criteria are shown in Table 2.

[0102] [Table 2]

[0103] determination Decision symbol No peeling in multiple cutting tests A Peeling occurred in some of the multiple cutting tests B There was peeling in multiple cutting tests C

[0104] [Thermal conductivity measurement]

[0105] A test piece for measuring thermal conductivity with a diameter of 10 mm and a thickness of 3 mm was prepared from a test piece that did not peel off among the test pieces used in the physical cutting test. The thermal conductivity was measured using the test piece for measuring thermal conductivity by the laser flash method. At this time, while observing the side of the test piece for measuring thermal conductivity, the height of the concave and convex portion was adjusted so that the center of the height was located at the center of the thickness of the test piece for measuring thermal conductivity. It should be noted that for test pieces in which the embedded component and the external component peeled off when the test piece was cut out, the thermal conductivity was determined to be unmeasurable (0 W / m·K). In the examples in which peeling occurred several times during multiple tests, or in the examples in which peeling did not occur during multiple tests, the average thermal conductivity of the test pieces that did not peel off was calculated and shown in Table 6.

[0106] [Surface temperature simulation]

[0107] In each embodiment, the model was created with the thickness of the embedded component being 2 mm, the thickness of the composite part (the interface between the embedded component and the outer component) being 3 mm, and the thickness of the outer component being 2 mm, and the surface temperature of the outer component was simulated. At this time, the inner peripheral surface temperature of the embedded component was set to 150°C, the temperature of the fluid around the outer component was set to 50°C, and the surface temperature of the outer component was calculated assuming that a fluid for cooling existed around the outer component. In addition, regarding the heat transfer from the surface of the outer component to the fluid, the heat transfer coefficient was set to 200 W / m 2 Based on the surface temperature of the external member obtained by the simulation, the heat dissipation performance was evaluated according to the criteria shown in Table 3. In this case, it can be said that the higher the surface temperature, the more efficiently the internal heat can be transferred, and the better the heat dissipation performance.

[0108] [Table 3]

[0109] determination Decision symbol Surface temperature is above 147°C AA Surface temperature is above 145℃ A Surface temperature is above 135℃ B Surface temperature is less than 135℃ C

[0110] [Compactness evaluation]

[0111] The compactness was evaluated according to the criteria shown in Table 4 based on the average maximum height h1 of the concavoconvex portions as the measurement item 2 in the measurement of the various parameters described above.

[0112] [Table 4]

[0113] determination Decision symbol The average maximum length h1 of the concave and convex parts is less than 0.25 mm AA The average maximum length h1 of the concave and convex parts is less than 1 mm A The average maximum length h1 of the concave and convex parts is less than 1.5mm B The average maximum length h1 of the concave and convex parts is 1.5 mm or more C

[0114] In the comprehensive judgment, evaluation was performed as shown in Table 5 based on the judgment symbols of the respective measurement items.

[0115] [Table 5]

[0116]

[0117] Table 6 shows the results of the sample tests measured as described above and the comprehensive evaluation.

[0118] [Table 6]

[0119]

[0120] The results shown in Table 6 confirmed that Examples 1 to 11 were superior to any of Comparative Examples 1 to 3 in comprehensive evaluation. Furthermore, Examples 2, 3, 4, and 5 were confirmed to be particularly superior.

[0121] In addition, by comparing Examples 1 to 8, Example 10 with Comparative Examples 1 to 3, it was confirmed that the thermal conductivity at the interface between the concave-convex portion embedded component and the motor housing would be increased by forming the first interface parameter to be greater than 1.30 and the second interface parameter to be greater than 4.00.

[0122] Furthermore, in Examples 4, 5, and 10, the outer peripheral surface of the insert member was subjected to surface roughening treatment by thermal spraying or cold spraying, and it was confirmed that the thermal conductivity was higher than that of other Examples.

[0123] Furthermore, a comparison between Examples 1 and 9 and other examples confirmed that even when the outer peripheral surface length ratio is large, the thermal conductivity does not increase when the average maximum height h1 of the concave and convex portions is large, as in Examples 1 and 9. Furthermore, it was confirmed that when the average maximum height h1 of the concave and convex portions is excessively large, as in Comparative Example 3, the thermal conductivity at the interface between the embedded component and the motor case decreases.

[0124] The above results confirm that thermal conductivity is high in examples such as Examples 4 and 5, where the first average solid area ratio A is low and the first interface parameter is large. In Example 5, which has the largest first interface parameter among all examples, the thermal conductivity at the interface between the embedded component and the motor housing is the highest.

[0125] Based on the above results, referring to Examples 1 to 11, it was confirmed that the slope of the average solid portion curve in the average solid portion total graph is preferably

[0126] 0.10 / B≤1.30.

[0127] Furthermore, referring to Examples 2 to 5, it was confirmed that when the slope of the average solid portion curve is small, the thermal conductivity at the interface between the embedded member and the motor case becomes high.

[0128] Based on the above results, referring to Examples 1 to 11, it can be confirmed that the area of the predetermined region in the average total area graph obtained in Measurement Item 6 is preferably

[0129] 0.10×B≥0.01.

[0130] Furthermore, referring to Examples 2 to 5, it was confirmed that when the area of the predetermined region is large, the thermal conductivity at the interface between the embedment member and the motor case becomes high.

[0131] The above results indicate that for embedded components with an outer peripheral length ratio of less than 1.15, as in Comparative Examples 1 and 2, separation between the embedded component and the outer component occurred during test piece excision. Furthermore, for embedded components with an outer peripheral length ratio greater than 1.15 and less than 1.30, as in Examples 6 to 8, separation sometimes occurred, confirming that an outer peripheral length ratio of 1.30 or greater is preferable.

[0132] The above results confirm that thermal conductivity increases when the height h2 is 0.40 mm or less, as in Examples 1 to 5. Furthermore, in Examples 6 to 8, although the height h2 was 0.40 mm or less, peeling was observed during test piece cutting, indicating that bonding properties were not necessarily high, thus confirming that thermal conductivity decreased.

[0133] [Effects]

[0134] By forming the concavo-convex portion of the present invention on the outer peripheral surface of the insert member 1, the thermal conductivity at the interface between the insert member 1 and the motor housing can be improved, so that the heat generated by the stator and other heating elements can be efficiently dissipated to the outside.

[0135] Multiple protrusions 10 are arranged on the outer peripheral surface of the insert member 1, with appropriate spacing between adjacent protrusions 10. This allows the casting material flowing into the mold to spread between the multiple protrusions 10, thereby suppressing the formation of gaps between the motor housing and the insert member 1 and improving thermal conductivity at the interface between the motor housing and the insert member 1.

[0136] The convex portion 10 and concave portion 13 of the insert member 1 of the present invention are formed within a length d1 to ensure the length of the contour line 30 without making the concave and convex portions excessively large. Consequently, the thermal conductivity at the interface between the insert member 1 and the motor housing can be well controlled. This prevents the motor housing from increasing in size and weight due to increased wall thickness, enabling a lighter and more compact rotating electrical machine. Furthermore, the thermal conductivity from the insert member 1 to the motor housing and the heat dissipation of the rotating electrical machine itself can be improved.

[0137] While the embodiments of the present invention have been described above, each aspect disclosed in this specification may be combined with any other features disclosed in this specification.

Claims

1. An insert member for a rotating electrical machine, the insert member being a substantially cylindrical member to be cast into an aluminum alloy motor housing of the rotating electrical machine, wherein: A concave-convex portion is formed on the outer peripheral surface of the embedded member, and the concave-convex portion includes a concave portion and a convex portion. In a cutting surface, When a line along the contour of the outer peripheral surface including the contour of the concavo-convex portion within a predetermined axial length range is defined as a contour line, The outer peripheral surface length ratio, which is a value obtained by dividing the length of the contour line by the predetermined axial length, is 1.15 or greater. The one cut surface is one of the cut surfaces that appear one by one on both sides of the central axis when the insert member is bisected along the axial direction by a virtual plane including the central axis of the insert member.

2. The embedded component for a rotating electrical machine according to claim 1, wherein The embedded component is divided into a solid portion area and a non-solid portion area within the range of the specified axial length, the solid portion area being an area on which the embedded component overlaps with a line segment parallel to the inner circumferential surface of the embedded component when the line segment overlaps with the one cutting surface, and the non-solid portion area being an area on which the embedded component does not overlap with a line segment parallel to the inner circumferential surface of the embedded component when the line segment overlaps with the one cutting surface. The value representing the ratio of the solid portion area on the line segment within the range of the predetermined axial length is defined as the solid portion ratio. The line segment is moved at a predetermined interval along the height direction of the concave-convex portion from the top end of the convex portion that protrudes most among the concave-convex portions toward the base end side of the convex portion within the one cut surface of the embedded component to obtain each measurement point, and a graph as a measured height is prepared by sequentially plotting the value of the solid portion ratio at each measurement point, with the solid portion ratio indicated on the horizontal axis and the distance from the top end in the height direction indicated on the vertical axis, as a solid portion total graph. The average of the solid portion ratios at the measurement points based on the plurality of cut surfaces is defined as an average solid portion ratio, and the solid portion total graph on which the average solid portion ratios are sequentially plotted is defined as an average solid portion total graph. In the average solid portion total graph, the position where the average solid portion ratio is 0 is set as the top end of the graph, and the position where the average solid portion ratio first exceeds 0.98, which is plotted sequentially from the top end side toward the base end side, is set as the base end of the graph, and When the distance from the top end to the base end in the figure is defined as the average maximum height of the concave and convex portions, The average maximum height of the concavoconvex portions is 0.15 mm or more and 1.50 mm or less.

3. The embedded component for a rotating electrical machine according to claim 2, wherein When the average solid portion ratio at a position shifted by 0.10 mm in height from the base end portion in the figure toward the top end portion in the figure is defined as A and the value obtained by dividing the outer peripheral surface length ratio by A is defined as the first interface parameter, The first interface parameter is greater than 1.

30.

4. The embedding member for a rotating electrical machine according to claim 1, wherein When the thickness of the insert member is half of the value obtained by subtracting the inner diameter from the outer diameter of the insert member, The thickness of the embedment member is equal to or greater than 0.8% of the outer diameter of the embedment member.

5. The embedding member for a rotating electrical machine according to claim 1, wherein The outer peripheral surface is subjected to a surface roughening treatment.

6. The embedding member for a rotating electrical machine according to claim 3, wherein The outer peripheral surface of the insert member has at least one of a region where the outer peripheral surface length ratio is less than 1.15 and a region where the first interface parameter is less than 1.30 in a portion in the axial direction.

7. The embedding member for a rotating electrical machine according to claim 3, wherein In the average entity total graph, The value obtained by subtracting the average solid portion ratio at a certain measured height from the average solid portion ratio at the base end portion in the figure is defined as the average non-solid portion ratio, and the average non-solid portion ratio at a position shifted by 0.10 mm in height from the base end portion in the figure toward the top end portion in the figure is defined as B. 0.10 / B≤1.30。 8. The embedding member for a rotating electrical machine according to claim 3, wherein In the average entity total graph, The value obtained by subtracting the average solid portion ratio at a certain measured height from the average solid portion ratio at the base end portion in the figure is defined as the average non-solid portion ratio, and the average non-solid portion ratio at a position shifted by 0.10 mm in height from the base end portion in the figure toward the top end portion in the figure is defined as B. 0.10×B≥0.01。 9. The embedding member for a rotating electrical machine according to claim 3, wherein In the average entity total graph, The height from the base end portion in the figure to the position where the average solid portion ratio is 0.30 is 0.40 mm or less.

10. The embedding member for a rotating electrical machine according to claim 3, wherein In the average entity total graph, The second interface parameter, which is a value obtained by dividing the outer peripheral surface length ratio by the height from the base end portion in the figure to the position where the average solid portion ratio is 0.30, is 4.00 or greater.

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