Insert member for rotary electric machine

Abstract

To provide an insert member for a rotary electric machine capable of improving joining strength with a motor case.SOLUTION: A plurality of projection parts are formed on an outer peripheral surface of a substantially cylindrical insert member. On one cut surface obtained by cutting the insert member, when overlapping a line segment of a predetermined axial direction length parallel to an inner peripheral surface of the insert member, an entity part region where the projection part overlaps the line segment on the line segment and a non-entity part region where the projection part does not overlap the line segment on the line segment are defined. On the line segment, when a value indicating a ratio of the entity part region is set as an entity part ratio, a figure formed by plotting the plurality of values of the entity part ratio in order is considered as an entity part aggregation figure. In a mean entity part aggregation figure obtained from a plurality of cross sections, when considering a position where a mean entity part ratio is zero as a tip end part on a figure, and considering a position where the mean entity part ratio exceeds 0.98 for the first time as a base end part on the figure, a mean maximum height of the projection part which is a distance from the tip end part on the figure to the base end part on the figure is 0.08% or more of an outer diameter of the insert member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an insert member for a rotating electrical machine. [Background technology]

[0002] Conventionally, aluminum alloys have been widely used as structural members in motor cases. In addition, in the motor case, a high-strength member made of an iron-based material and formed into a substantially cylindrical shape may be used as an insert member in the portion where the stator is disposed to supplement strength. In relation to this, it has been proposed to improve the fixation and retention of the insert member to the motor case by providing irregularities on the outer peripheral surface of the insert member (see, for example, Patent Documents 1, 2, and 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-169500 ​​A [Patent Document 2] JP 2011-101513 A [Patent Document 3] Patent No. 6655560 Summary of the Invention [Problem to be solved by the invention]

[0004] When forming a motor case from an aluminum alloy, the above-mentioned insert member may be cast in. After casting, the insert member is used as a stator holder by processing its inner peripheral surface so as to fit into the outer peripheral surface of the stator. In this case, if the joining strength between the motor case and the insert member is insufficient, the insert member may be displaced relative to the motor case, causing the motor shaft to run out, which may result in a decrease in output due to increased friction or a decrease in durability due to increased vibration.

[0005] The technology of the present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide an insert member for a rotating electric machine that can improve the joining strength with a motor case. [Means for solving the problem]

[0006] In order to solve the above problems, the technology of the present invention employs the following configuration. An insert member for a rotating electric machine as one aspect of the technology of the present invention is a substantially cylindrical insert member that is cast into an aluminum alloy motor case of a rotating electric machine, and a plurality of protrusions are formed on the outer peripheral surface of the insert member, and in a cross section, which is one of the cut surfaces that appear on both sides of the central axis when the insert member is cut into two parts along the axial direction by an imaginary plane including the central axis of the insert member, the insert member defines, within a predetermined axial length range, a solid part region where the protrusions overlap on the line segment when a line segment parallel to the inner peripheral surface of the insert member is superimposed on the cross section, and a non-solid part region where the protrusions do not overlap on the line segment, and on the line segment, A value indicating the proportion of the solid portion region within the specified axial length range is defined as a solid portion ratio, and the line segment is moved from the tip end of the protrusion toward the base end side at a specified pitch along the height direction of the protrusion in the entire cross section of the insert member, and values ​​of the solid portion ratio at each measurement point are plotted in order, with the horizontal axis representing the solid portion ratio and the vertical axis representing the distance from the tip end in the height direction as the measurement height being defined as a solid portion summary diagram, an average of the solid portion ratios at each measurement point obtained from a plurality of the entire cross sections is defined as an average solid portion ratio, and the solid portion summary diagram on which the average solid portion ratio is plotted is defined as an average solid portion summary diagram, and a position where the average solid portion ratio is 0 in the average solid portion summary diagram is defined as a tip end in the diagram. When the position where the average solid portion ratio, plotted in sequence from the tip end side to the base end side, first exceeds 0.98 is defined as the base end on the figure, and the distance from the tip end on the figure to the base end on the figure is defined as the average maximum height of the protrusions, the average maximum height of the protrusions is 0.08% or more of the outer diameter of the insert member.

[0007] Furthermore, in the insert member, the average maximum height of the protrusions may be within a range of 0.08% to 1% of the outer diameter of the insert member.

[0008] Furthermore, in the average solid part summary diagram, the sum of the average solid part ratios in the range from the midpoint of the average maximum height of the protrusions to the base end on the diagram, excluding the position of the base end on the diagram, may be greater than the sum of the average solid part ratios in the range from the midpoint of the average maximum height of the protrusions to the base end on the diagram, excluding the position of the tip end on the diagram.

[0009] Furthermore, two or more measurement points plotted on the average solid part summary chart may be included within a range in which the difference in the average solid part ratios of the two or more measurement points is 0.10 or less and the difference in the measurement heights of the two or more measurement points is 0.05 mm or more.

[0010] Further, the average solid part ratios plotted on the average solid part summary chart may be configured so that the average solid part ratios have a maximum peak and a minimum peak, and the maximum peak is located closer to the tip end on the chart than the minimum peak.

[0011] In addition, in the average solid body summary chart, the average solid body ratio at the minimum peak may be 0.08 or more.

[0012] In addition, in the average solid body summary chart, a difference between the average solid body ratio value at the maximum peak and the average solid body ratio value at the minimum peak may be 0.02 or more and 0.20 or less.

[0013] In addition, in the average solid body summary chart, the average solid body ratio at the maximum peak may be 0.50 or less.

[0014] The protrusion may be formed on only a partial area of ​​the outer circumferential surface of the insert member. Effect of the Invention

[0015] According to the present invention, it is possible to provide an insert member for a rotating electric machine that can improve the joining strength with a motor case. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an overall view of an insert member for a rotating electrical machine according to an embodiment, and an enlarged view of a part of the outer circumferential surface thereof. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of a predetermined cut surface of the insert member for a rotating electric machine according to the embodiment. [Diagram 3] FIG. 3 is an average solid portion summary diagram for explaining the relationship between the measurement height and the average solid portion ratio of an insert member for a rotating electrical machine in one example according to an embodiment. [Figure 4] FIG. 4 is a diagram showing an average substantial part summary of an insert member for a rotating electrical machine in one example according to the embodiment. [Diagram 5] FIG. 5 is a diagram showing an average substantial part summary of an insert member for a rotating electrical machine in one example according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configurations described in the following embodiments are not intended to limit the technical scope of the invention unless otherwise specified. Each configuration and combination thereof in the following embodiments is merely an example, and addition, omission, substitution, and other modifications of the configurations are possible as appropriate within the scope of the gist of the present invention.

[0018] <Embodiment> [Structure / manufacturing method] 1 is an overall view of an insert member 1 for a rotating electric machine according to an embodiment (hereinafter referred to as "insert member 1"), and an enlarged view of a part of its outer circumferential surface. In this embodiment, the direction along the central axis C of the insert member 1 is defined as the axial direction, and the direction perpendicular to the axial direction from the central axis C toward the outer circumferential surface of the insert member 1 is defined as the radial direction. The direction around the central axis C along the outer circumferential surface of the insert member 1 is defined as the circumferential direction. Such axial, radial, and circumferential directions are merely directions for indicating the relative positional relationship of each element in the insert member 1.

[0019] The insert member 1 according to this embodiment is, for example, a cast iron material formed in a substantially cylindrical shape centered on the central axis C, and a plurality of protrusions 10 are formed on the outer circumferential surface (surface). The rotating electric machine to which the present invention is applied is, for example, a motor used in an electric vehicle or the like. However, the rotating 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 may be appropriately changed depending on the purpose of use. In addition, the outer diameter OD is a value corresponding to the distance between two parallel planes when the insert member 1 is placed between two parallel planes so that the central axis C of the insert member is parallel, and the tip end 11 of the protrusion 10 on the outer circumferential surface of the insert member 1 is brought into contact with each of the two parallel planes.

[0020] The rotating electric machine includes, for example, a rotating shaft, a rotor, a stator, a motor case, bearings, and other components. The motor case has a cylindrical portion with the inside hollowed out in a cylindrical shape. The stator is generally formed of an electromagnetic steel sheet or the like, and is fitted into the inner peripheral portion of the cylindrical portion. Here, the insert member 1 is used by being cast into the inner peripheral portion of the motor case made of an aluminum alloy. As a result, the motor case and the insert member 1 become a composite structure in which at least a part of the outer peripheral surface of the insert member 1 is covered with an aluminum alloy. In addition, when the stator is fitted into the inner peripheral portion of the insert member 1, the stator is shrink-fitted. Since the linear expansion coefficient of the material of the stator and the linear expansion coefficient of the insert member 1 are close to each other, the fitting strength between the stator and the insert member 1 is maintained even when heat is generated during operation of the motor.

[0021] Generally, the operating temperature of a motor is −30° C. to 150° C. The material used for the stator is generally an electromagnetic steel sheet. -6 / K or more 13.0×10 -6 When the stator is formed using a material having a linear expansion coefficient of 1 / K or less, the linear expansion coefficients of the mating stator and insert member 1 become similar. This helps to maintain high fitting strength between the outer periphery of the stator and the inner periphery of the insert member 1 even after the stator is fitted into the insert member 1 cast into the motor case.

[0022] The material of the insert member 1 described above is not particularly limited as long as it has sufficient strength compared to the aluminum alloy used for the motor case and has a linear expansion coefficient within the above range. Typically, flake graphite cast iron such as JIS FC250 equivalent material can be used, taking into consideration manufacturability and workability.

[0023] The method for forming the protrusion 10 of the insert member 1 is not particularly limited, but for example, centrifugal casting can be used. Alternatively, the protrusion 10 can be formed by machining a cylinder made of cast iron.

[0024] FIG. 2 is a cross-sectional view showing an example of a predetermined cut surface of the insert member 1 according to the embodiment. The predetermined cut surface in this embodiment is a cross section that is one of the cut surfaces that appear on both sides of the central axis C when the insert member 1 is cut into two parts along the axial direction by a virtual plane including the central axis C of the insert member 1. The length of the cross section in the axial direction is equal to or longer than the length d1 described below. In FIG. 2, the A-A' cross section in FIG. 1 is shown as an example of the predetermined cut surface. Also, the reference numeral 40 shown in FIG. 2 indicates the inner peripheral surface of the insert member 1. Hereinafter, this will be referred to as the "inner peripheral surface 40". Below, the multiple protrusions 10 provided on the insert member 1 according to this embodiment will be described with reference to FIG. 2.

[0025] The protrusion 10 is a part of the insert member 1, and is formed on the outer peripheral surface of the insert member 1. The protrusions 10 may be arranged in a plurality of positions and density that are discontinuous and irregular (random) in the axial and circumferential directions, or may be arranged in a plurality of positions and density that are continuous and regular. The protrusions 10 have a tip end 11 and a base end 12, and are formed so as to protrude from the base end 12 to the tip end 11 toward the outside in the radial direction of the insert member 1.

[0026] Furthermore, the locations where the multiple protrusions 10 are formed on the outer peripheral surface of the insert member 1 may be limited to a certain area, or a process may be performed to remove some of the multiple protrusions 10. As a result, the multiple protrusions 10 may be formed only on a certain area of ​​the outer peripheral surface of the insert member 1.

[0027] The protrusion 10 may be formed by casting while applying centrifugal force by centrifugal casting. In this case, the tip 11 of the protrusion 10 is formed based on the inner peripheral surface of the mold. If the inner peripheral surface of the mold is a perfect circle, the distance from the central axis C of the insert member 1 will be almost equal, whereas the distance from the central axis C of the base end 12 may be uneven. Therefore, the height of the protrusion 10 is measured based on the tip 11 in the process of deriving the height of the protrusion 10 using a substantial part summary diagram described later. However, the method of forming the protrusion 10 is not limited to this, and the protrusion 10 may be formed, for example, by performing machining such as cutting on the outer peripheral surface of a cylindrical member.

[0028] The shape of the protrusion 10 is not particularly limited. The protrusion 10 may have, for example, a spirally continuous shape, or a circularly continuous shape along the circumferential direction. For example, the protrusion 10 can be formed into a spiral or circular shape by directly performing machining such as cutting on the outer circumferential surface of the insert member 1. The shape of the protrusion 10 may be any shape that is effective in the actual cutting test, tensile simulation, and shear simulation described below.

[0029] [Body ratio] A substantial region 21 and a non-substantial region 22 are defined by the protrusion 10 of the insert member 1. As shown in FIG. 2, the substantial region 21 and the non-substantial region 22 are identified based on whether a line segment 20 having a length d1 (an example of the "predetermined axial length" in the present invention) overlaps with the protrusion 10 when the line segment 20 is superimposed on a predetermined cut surface. More specifically, within the range of length d1, the region where the line segment 20 overlaps with the protrusion 10 is defined as the substantial region 21, and the region where the line segment 20 does not overlap with the protrusion 10 is defined as the non-substantial region 22. The line segment 20 is defined as a virtual line parallel to the inner circumferential surface 40 (i.e., parallel to the central axis C) on the predetermined cut surface. These are line segments that are provided for the sake of convenience in order to identify the solid body region 21 and the non-solid body region 22.

[0030] The solid part ratio is a value indicating the proportion of the solid part region 21 formed in the range of the length d1. By moving the line segment 20 at a predetermined pitch along the direction of the arrow A20 in FIG. 2 (from the tip end 11 side to the base end 12 side in the radial direction), the length of the solid part region 21 at a measurement height at an arbitrary measurement point among the measurement heights, which are the distances in the radial direction from the tip end 11, can be obtained. In this case, the ratio of the total length of the solid part region 21 to the length d1 at the arbitrary measurement height is referred to as the "solid part ratio". By performing the same operation on multiple cross sections, collecting the solid part ratios of the protrusion 10 on each cut surface, and averaging the solid part ratios at the measurement heights of each measurement point, an average solid part ratio, which is the average value of the solid part ratios based on multiple cross sections at the arbitrary measurement height, can be obtained.

[0031] [Substance summary chart] As shown in FIG. 2, the line segment 20 is moved toward the base end 12 (along the direction of the arrow A20) at a predetermined pitch, and the acquisition of the solid part ratio is repeated until the solid part ratio becomes 1.00. The acquired solid part ratio is plotted on a graph, and the shapes of the multiple protrusions 10 appearing on a predetermined cut surface can be graphed as a single shape that aggregates the shapes of the multiple protrusions 10. This is called a "solid part summary chart." The solid part summary chart is a graph in which the vertical axis represents the measured height, which is the distance from the tip 11 of the protrusion 10 in the height direction, and the horizontal axis represents the solid part ratio. In addition, by performing the work of obtaining the solid part ratio on multiple predetermined cut surfaces and creating an average solid part summary chart, it is possible to grasp the formation state of the protrusions 10 in the insert member 1 on an average basis. In this case, in any predetermined cut surface, the reference point in the height direction is set to "the tip 11 of the most protruding protrusion 10 among the multiple protrusions 10 within the range of the length d1 (predetermined axial length)," and the pitch at which the line segment 20 is moved is also set to the same pitch. This allows the measurement height to be determined uniquely even for a plurality of predetermined cut surfaces. In this embodiment, the protrusions identified by the graph shapes appearing in the average solid part summary diagram are referred to as "aggregated protrusions" in the average solid part summary diagram. FIG. 3 shows an average solid part summary diagram in which average solid part ratios that can be intermittently obtained from six predetermined cut surfaces of a sample are plotted in order with a predetermined pitch of 0.05 mm and a length d1 of 14.7 mm as an example of the insert member 1 according to this embodiment. As shown in FIG. 3, the protrusions identified by the graph shapes appearing in the average solid part summary diagram are shown as aggregated protrusions 30.

[0032] [Measurement method] The method of measuring the solid area 21 and the non-solid area 22 will be described below with reference to FIG. 2. First, the method of preparing the measurement sample will be described. The insert member 1 cut in a direction including the central axis C and along the axial direction is further cut into a size that allows resin embedding and polishing, and resin embedding is performed with the cross section on which the solid area ratio is measured facing downward. After the resin has solidified, the cross section side is polished under running water using waterproof emery paper. At this time, the grit size of the waterproof emery paper is changed in the order of #220, #400, #800, #1000, and #1500. After polishing is completed, the solid area ratio is measured. The observation surface after polishing corresponds to the specified cut surface.

[0033] In this embodiment, a digital microscope RX-100 manufactured by Hirox Corporation was used to measure the solid part ratio. The objective lens magnification during measurement was 20x or 50x, and a grid and automatic width tool were used using the software provided with the microscope. The measurement sample after polishing as described above was set so that the inner peripheral surface 40 of the insert member 1 was parallel to the horizontal axis of the grid displayed on the observation monitor. The measurement sample was then translated to a position where the outer peripheral surface of the insert member 1 could be observed. Next, the automatic width tool was used to measure the measurement sample in the horizontal axis direction. . Measurement by the automatic width tool is an automatic measurement using gradation density, so that the gradation density is adjusted each time so that the automatic discrimination between the insert member area corresponding to the solid part region 21 and the resin area corresponding to the non-solid part region 22 is appropriate, and the length of the solid part region 21 at an arbitrary measurement height is measured by moving at a predetermined pitch. In this embodiment, the line segment 20 indicates the measurement position of the automatic width tool. By moving the line segment 20 along the radial direction of the insert member 1 from the tip end 11 side toward the base end 12 side, the axial length of the solid part region 21 at an arbitrary measurement height from the tip end 11 can be measured. At this time, the line segment 20 is moved at a predetermined pitch of 0.05 mm or 0.025 mm from the tip end 11 of the protrusion 10 that protrudes most within the range of length d1 in all cross sections toward the base end 12 side, and the measurement is performed.

[0034] FIG. 2 shows the case where the line segment 20 is at position 20a and the case where it is at position 20b. When the line segment 20 is at the measurement height shown in position 20a, the line segment 20 overlaps with the tip portion 11 that protrudes the most in the length d1. Using this as a reference, the line segment 20 is moved in the direction of arrow A20 (toward the base end portion 12). Position 20b is an example of a measurement height when the line segment 20 is moved an arbitrary number of times at a predetermined pitch. When the line segment 20 is at the position shown in position 20b, it can be said that the insert member 1 forms a solid portion region 21 shown by a dashed line and a non-solid portion region 22 shown by a solid line of the line segment 20. Line segment 20 is moved along arrow A20, and from the position where the solid part ratio described below exceeds 0.98 for the first time, line segment 20 is further moved along arrow A20, and the measurement is terminated when the entire range of length d1 on line segment 20 becomes solid part region 21 (i.e., when the solid part ratio becomes 1.00).

[0035] [Parameters for average solid part summary chart] FIG. 3 shows an average solid part summary diagram in which the average solid part ratios based on a certain sample are plotted in order. As shown in FIG. 2 and FIG. 3, the position corresponding to "the tip 11 of the most protruding protrusion 10 among the multiple protrusions 10 within the range of length d1" in the average solid part summary diagram is referred to as "the tip on the diagram". The tip on the diagram is a position that coincides with the tip of the aggregated protrusions 30 described above. The measurement height at the tip on the diagram is 0 mm, and the average solid part ratio is 0. In addition, "the position where the average solid part ratio exceeds 0.98 for the first time among the points plotted in the average solid part summary diagram" is referred to as "the base on the diagram".

[0036] The average solid part summary diagram shown in FIG. 3 shows the maximum peak value and the minimum peak value. The maximum peak value is the average solid part ratio at the maximum peak among the peaks in the average solid part curve, which is called the "average solid part curve" by connecting each measurement point plotted on the average solid part summary diagram with a line, and the minimum peak value is the average solid part ratio at the minimum peak among the peaks in the average solid part curve plotted on the average solid part summary diagram. In one example of the average solid part summary diagram shown in FIG. 3, the absolute value of the measurement height from the tip to the maximum peak on the diagram is 0.20 mm, the maximum peak value is 0.45, the absolute value of the measurement height from the tip to the minimum peak on the diagram is 0.45 mm, and the minimum peak value is 0.30. In this case, the maximum peak appears closer to the tip side on the diagram than the minimum peak in the measurement height direction.

[0037] The average maximum height h1 of the aggregated protrusions 30 shown in Fig. 3 is the distance from the tip to the base on the vertical axis of the average solid part summary diagram. The solid part ratio at each measurement point on the solid part summary diagram is measured from the tip 11 of the protrusion 10 located at the top toward the central axis C located at the bottom, so the measured height at each measurement point is displayed as a negative value. The same is true for an average solid part summary diagram obtained from multiple solid part summary diagrams, but the average maximum height h1 of the actual protrusions 10 is the absolute value of the vertical axis value on the average solid part summary diagram.

[0038] In this embodiment, the protrusion 10 is formed so that the maximum peak value is ≦0.50 in the average solid part summary diagram. As a result, the protrusion 10 is formed so that the base end 12 side is closer to the tip end 11 side. This allows the aluminum alloy to be easily poured into the mold when the insert member 1 is cast from an aluminum alloy toward the base end 12 side of the protrusion 10, preventing a gap from being generated at the joint between the insert member 1 and the motor case. In addition, when a load is applied to the protrusion 10, the protrusion 10 is less likely to break. The shape of the tip 11 of the protrusion 10 is not particularly limited, and the tip 11 may be formed, for example, in a round, angular, or flat shape as long as it is formed so that the maximum peak value is ≦0.50.

[0039] The plurality of protrusions 10 may be formed so that the maximum peak appears closer to the tip end side than the minimum peak in the average solid part summary diagram of the protrusions 30. In addition, in the average solid part summary diagram, the total value of the average solid part ratio in the range from the center position of the average maximum height h1 of the aggregated protrusions 30 to the base end on the diagram, excluding the position of the base end on the diagram, may be greater than the total value of the average solid part ratio in the range from the center position of the average maximum height h1 of the aggregated protrusions 30 to the base end on the diagram, excluding the position of the tip end on the diagram. Here, if the center position of the average maximum height h1 of the aggregated protrusions 30 coincides with the measurement point of the average solid part ratio, the center position of the average maximum height h1 of the aggregated protrusions 30 is included on the tip end side on the diagram. According to these, it is possible to determine whether the tip end side on the diagram of the aggregated protrusions 30 is thinner than the base end side on the diagram.

[0040] In the aggregated protrusions 30, the position of the maximum peak may be located closer to the base end in the figure than the tip end in the figure where the measurement height is 0 mm. In this way, in the aggregated protrusions 30, since no maximum peak is formed at the tip end in the figure, damage or breakage of the tip end 11 of the protrusion 10 can be prevented.

[0041] The average solid part ratio may include two or more measurement points within a range where the difference between the average solid part ratios of two or more measurement points is 0.10 or less and the difference between the measurement heights of two or more measurement points is 0.05 mm or more among the multiple measurement points plotted on the average solid part summary chart. As an example, FIG. 3 illustrates plots of points N1 to N3. The values ​​plotted at points N1 to N3 are plotted within a range where the difference between the average solid part ratios is a maximum of 0.007 and the difference between the measurement heights is a maximum of 0.10 mm. In this way, when the difference between the average solid part ratios of two or more measurement points is 0.10 or less and the difference between the measurement heights of two or more measurement points is 0.05 mm or more, the slope of the average solid part curve in the average solid part summary chart becomes steep. In this way, in the part of the aggregated protrusions 30 in the average solid part summary diagram, where the slope of the average solid part curve is steep, on average, a part of the multiple protrusions 10 is formed approximately perpendicular to the outer circumferential surface of the insert member 1. As a result, even if the aggregated protrusions 30 have a graph shape in which no maximum peak appears, for example, the joint strength between the motor case and the insert member 1 can be improved by having a part of the aggregated protrusions 30 where the slope of the graph is steep.

[0042] In the average solid part summary diagram, the difference between the maximum peak value and the minimum peak value may be 0.02 or more and 0.20 or less. When the difference between the maximum peak value and the minimum peak value is less than 0.02, the joint strength between the motor case and the insert member 1 may be lower than when the difference between the maximum peak value and the minimum peak value is 0.02 or more. When the difference between the maximum peak value and the minimum peak value exceeds 0.20, when the insert member 1 is cast from an aluminum alloy, the aluminum alloy poured into the mold may not easily flow to the base end 12 side of the protrusion 10, or a part of the formed protrusion 10 may break or be damaged. On the other hand, by setting the difference between the maximum peak value and the minimum peak value to 0.02 or more and 0.20 or less, it is possible to ensure high joint strength while preventing damage to the protrusion 10.

[0043] In the average body summary chart, the minimum peak value may be 0.08 or more. If the value is below 0.08, it may be difficult to form the protrusions 10 during the manufacturing process of the insert member 1, and the protrusions 10 may be prone to breakage. In contrast, by setting the average solid part ratio of the minimum peak value to 0.08 or more, it is possible to prevent the number of protrusions 10 from becoming excessively small. In addition, the lack of strength caused by the protrusions 10 becoming excessively thin is eliminated, making the protrusions 10 less likely to break.

[0044] In the average solid part summary diagram, the maximum peak value may be 0.50 or less, and more preferably 0.45 or less. If the maximum peak value is greater than 0.50, when the insert member 1 is cast from an aluminum alloy, the aluminum alloy poured into the mold may not easily spread between the multiple protrusions 10. In particular, the aluminum alloy may not easily spread toward the base end 12. Furthermore, the edge of the protrusion 10 may be chipped near the position where the average solid part ratio value is the maximum peak, or the protrusion 10 may easily break near the position where the average solid part ratio value is the minimum peak. On the other hand, if the maximum peak value is 0.50 or less, more preferably 0.45 or less, these problems can be prevented.

[0045] [Testing and Simulation] The insert members 1 of Examples 1 to 13 of the present invention and the insert members according to Comparative Examples were evaluated by tests and simulations using samples. Specifically, the insert members of the Examples and Comparative Examples (hereinafter referred to as Examples, etc.) were subjected to measurement and evaluation of various parameters, actual cutting tests, tensile simulations, and shear simulations.

[0046] [Measurement and evaluation of various parameters] Various parameters of the insert members according to each of the examples were measured and evaluated. Table 1 shows the results of each item of the insert members according to the examples. For the insert members according to the examples, the pitch was set to 0.05 mm or 0.025 mm, the length d1 was set to 14.7 mm or 5.57 mm, and a high objective lens magnification was selected when the average maximum height h1 of the protrusions was small, and an average solid part summary diagram was created. As a reference example, various parameters of an insert member without protrusions 30 are shown in Table 1.

[0047] [1. Ratio of average maximum height h1 of protrusions to outer diameter OD] In item 1, the ratio of the average maximum height h1 of the aggregated protrusions 30 to the outer diameter OD of the insert member was calculated as a percentage in the average solid part summary diagram of each example, etc. This confirmed whether the aggregated protrusions 30 in the examples, etc. were formed within a range of 0.08% to 1% of the outer diameter OD of the insert member.

[0048] [2. Is the base end thicker than the tip end?] In item 2, based on the average solid part summary diagram in each example, a judgment was made as to whether the total value of the average solid part ratio excluding the tip position on the diagram is greater than the total value of the average solid part ratio excluding the base end position on the diagram in the range from the center position of the average maximum height h1 of the aggregated protrusions 30 to the tip position on the diagram. Based on the average solid part summary diagram in each example, if the base end side on the diagram is larger than the tip end side on the diagram (i.e., if the base end side on the diagram is thicker), it is marked with "O", and if the base end side on the diagram of the aggregated protrusions 30 is equal to or smaller than the tip side on the diagram, it is marked with "X".

[0049] [3. Whether or not the test includes two or more measurement points where the difference in the average solid part ratio is 0.10 or less and the difference in measurement height is 0.05 mm or more] In item 3, it was determined whether the average solid part ratio plotted in the average solid part summary diagram in each Example, etc., included two or more measurement points where the difference in the average solid part ratio was 0.10 or less and the difference in the measurement height was 0.05 mm or more. If the points that could meet these conditions were included, it was marked as " If it was not included, it was marked with an “×”.

[0050] [4. Presence or absence of maximum and minimum peaks] In item 4, in the average solid part summary diagram in each Example, etc., if a maximum peak and a minimum peak exist, and the maximum peak is located on the tip side of the diagram from the center position of the average maximum height h1 of the protrusions and is located on the tip side of the diagram from the minimum peak, it is marked as "O". In contrast, if the maximum peak is located on the tip side of the diagram from the center position of the average maximum height h1 of the protrusions and is located on the base side of the diagram from the minimum peak, or if no peak appears on the average solid part summary diagram, it is marked as "X".

[0051] [5. Minimum peak value][6. Difference between maximum peak value and minimum peak value] In item 5, the minimum peak value was determined based on the average solid part summary chart in each Example, etc. In item 6, the difference between the maximum peak value and the minimum peak value was determined based on the average solid part summary chart in each Example, etc.

[0052] [7. Maximum Peak Position] In item 7, based on the average solid part summary diagram in each Example, if the maximum peak is located closer to the base end than to the tip end on the diagram, it is marked as "O", and if no peak appears on the average solid part summary diagram, it is marked as "X". [Table 1]

[0053] Further, an actual cutting test, a tensile simulation, and a shear simulation were performed on the insert members according to the examples and the like that were measured as shown in Table 1. The tests and simulations are described below.

[0054] [Cutting test] In the actual cutting test, the insert member in the examples was cast in an aluminum alloy equivalent to the motor case. In addition, test pieces 20 mm square were cut out with the insert member and the aluminum alloy bonded together to confirm the bonding strength. In this case, if the bond between the insert member and the aluminum alloy was maintained in all six test pieces subjected to the actual cutting test, it was rated as A0, if the insert member and the aluminum alloy peeled off in some of the test pieces, it was rated as B0, and if the insert member and the aluminum alloy peeled off in all six test pieces subjected to the actual cutting test, it was rated as C0. The results are shown in Table 4 and will be described in detail later.

[0055] [Tension simulation] Usually, when an insert member cast in aluminum alloy is cut out from the cast state, the aluminum alloy located outside the insert member solidifies and shrinks during the cooling process after die casting, and the aluminum alloy tightens the protrusions formed on the outer peripheral surface of the insert member, and a part of the tightening force is released from the state where the insert member and the aluminum alloy were joined. Therefore, it is difficult to measure the actual joint strength. In contrast, in this simulation, a protrusion with a shape in which multiple protrusions are consolidated into one based on the average solid part summary diagram is formed, and the radial displacement difference of the protrusions when a difference in the amount of expansion occurs due to the difference in the linear expansion coefficient between the aluminum alloy and the cast iron insert member is evaluated by simulation using CAE analysis. In this case, the evaluation was performed under the following temperature conditions: high temperature: 150°C, medium temperature: 85°C. A representative example will be described with reference to FIG. 3.

[0056] As described above, FIG. 3 shows the aggregated protrusion 30, which is a shape in which a plurality of protrusions 10 are aggregated into one based on the average solid part summary diagram. The aggregated protrusion 30 is defined by an area in which the vertical axis direction can be regarded as the radial direction in the insert member 1 and the horizontal axis direction can be regarded as the axial direction in the insert member 1 in the average solid part summary diagram. The aggregated protrusion 30 is reduced so that the horizontal axis direction length in the average solid part summary diagram of the aggregated protrusion 30 is 1 / 2 while maintaining the vertical axis length (referred to as a "reduced aggregated protrusion"), and further rotated about the vertical axis of the average solid part summary diagram as an axis of symmetry, whereby a model of the protrusion shape of the insert member 1 is aggregated into one (referred to as a "model protrusion"). Here, the reason for reducing the horizontal axis length of the aggregated protrusion 30 to 1 / 2 is to define a model protrusion shape in which protrusion shapes existing within the range of length d1 are aggregated into one, and to perform a simulation using the model protrusion. The thickness of the reduced aggregated protrusion is calculated by converting the length in the horizontal direction of the reduced aggregated protrusion to the length d1. In this simulation, a model is created in which an insert member with two model protrusions formed on the outer surface at 180° opposite each other is cast in aluminum alloy, and a tensile evaluation simulating thermal expansion is performed by simulating the radial displacement when the temperature change under the above temperature conditions is applied to the model using CAE analysis. At this time, a judgment is made as shown in Table 2 based on the radial displacement difference between the aluminum alloy and the insert member and the ratio of that displacement difference to the average maximum height h1 of the protrusions. [Table 2]

[0057] [Shear Simulation] In the shear simulation, a model was created in which an insert member with one model protrusion formed on its outer surface was cast in aluminum alloy, and a shear evaluation was performed assuming the axial torque acting on the insert member. In this simulation, a load assuming shear occurring in the axial and circumferential directions was applied to the model protrusion cast in aluminum alloy. In this case, it was assumed that the shear load was a load equivalent to the motor shaft torque acting on the outer surface of the insert, and the radial displacement difference between the aluminum alloy and the insert member was judged based on the ratio of that displacement difference to the average maximum height h1 of the protrusion, as shown in Table 3. [Table 3]

[0058] Table 4 shows the results of the actual cutting test, tensile simulation, and shear simulation measured as described above, as well as an overall judgment based on these results. [Table 4]

[0059] For the overall assessment, if the actual cutting test, tensile simulation, and shear simulation all received an A rating, the overall assessment was A; if any of the actual cutting test, tensile simulation, and shear simulation received a C rating, the overall assessment was C; and for all other results, the overall assessment was B.

[0060] From the above results, and referring to the examples, it was confirmed that the average maximum height h1 of the aggregated protrusions 30 is preferably formed within a range of 0.08% to 1% of the outer diameter OD, and more preferably the average maximum height h1 of the aggregated protrusions 30 is formed at 0.26% or more of the outer diameter OD. It was also confirmed that if the average maximum height h1 of the aggregated protrusions 30 is less than 0.26%, the bonding strength between the insert member and the motor case decreases.

[0061] From the above results, by comparing Examples 1 to 5 and 8 with Examples 6, 7, 9 to 13 and Comparative Example, it was confirmed that if the minimum peak value is 0.08 or more, the results of the tensile simulation and the shear simulation are excellent even under high temperature conditions. Similarly, it was confirmed that the difference between the maximum peak value and the minimum peak value is preferably 0.02 or more.

[0062] In view of these results, it can be said that the insert member 1 according to this embodiment can prevent insufficient joint strength with the motor case.

[0063] Next, of the above-mentioned test and simulation, the average substantial part summary diagram and the mode of the insert member 1 in each example will be described by taking, as an example, Example 13, Example 11, and Example 2. FIG. 4 is an average substantial part summary diagram of the insert member 1 in Example 13 according to this embodiment. FIG. 5 is an average substantial part summary diagram of the insert member 1 in Example 11 according to this embodiment. FIG. 3 is an average substantial part summary diagram of the insert member 1 in Example 2 according to this embodiment. Below, the average substantial part summary diagram and the insert member 1 in each example according to this embodiment will be described with reference to FIG. 4 for Example 13, FIG. 5 for Example 11, and FIG. 3 for Example 2.

[0064] FIG. 4 shows a reduced aggregated protrusion 301 in which the aggregated protrusion 30 of Example 13 is reduced to 1 / 2 in the horizontal axis direction of the average substance part summary diagram. In view of the model protrusion based on the reduced aggregated protrusion 301, it was confirmed that in the insert member 1 according to the average substance part summary diagram shown in FIG. 4, the aggregated protrusion 30 has a cross-sectional shape of a substantially triangular shape protruding in the radial direction and has a shape that spreads from the tip end 11 to the base end 12. In addition, the protrusions 10 formed on the insert member 1 may exist individually, or may be formed continuously along the circumferential direction. Furthermore, when formed continuously along the circumferential direction, they may be arranged in a spiral shape on the outer peripheral surface of the insert member 1, or may be formed in a ring shape and continuously in the circumferential direction. In Example 13, the maximum height of the aggregated protrusions 30 is formed to be 0.08% or more of the outer diameter OD of the insert member 1, and it was confirmed that the insert member 1 and the motor case on its outer peripheral surface side have a practical joint strength.

[0065] 5 shows a reduced aggregated protrusion 302 in which the aggregated protrusion 30 of Example 11 is reduced to 1 / 2 in the horizontal axis direction of the average solid part summary diagram. In view of the model protrusion based on the reduced aggregated protrusion 302, it was confirmed that the average solid part curve has a steep part in the insert member 1 according to the average solid part summary diagram shown in FIG. 5. When the average solid part curve is formed to have a steep part, the force caused by the solidification shrinkage and thermal shrinkage of the aluminum alloy generated in the circumferential direction is likely to occur in the circumferential direction, and excellent results were obtained without peeling in the solid cutting test, so it was confirmed that this helps improve the bonding strength between the insert member 1 and the motor case on its outer peripheral surface side.

[0066] Fig. 3 shows a reduced aggregated protrusion 303 in which the aggregated protrusion 30 of Example 2 is reduced to 1 / 2 in the horizontal axis direction of the average solid part summary diagram. According to this, in the insert member 1 according to the average solid part summary diagram shown in Fig. 3, the aggregated protrusion 30 has a hook shape in which a maximum peak and a minimum peak are formed in the middle part between the tip end 11 and the base end 12, as shown in Fig. 2. In this case, it was confirmed that in the average solid part summary diagram, the maximum peak appears closer to the tip end side than the minimum peak.

[0067] As described above, in the embodiment 2, statistically speaking, the protrusion 10 formed on the outer peripheral surface of the insert member 1 has a hook shape. As a result, the hook shape of the protrusion 10 tightly meshes with the motor case on the outer peripheral surface side, and the joining strength between the insert member 1 and the motor case on the outer peripheral surface side is significantly improved.

[0068] [Effects] By forming the protrusions 10 on the outer peripheral surface of the insert member 1, the joining strength between the insert member 1 and the motor case on the outer peripheral surface side thereof can be improved. This makes it possible to prevent the insert member 1 from being displaced or shifted in the axial, circumferential and radial directions relative to the insert member 1 .

[0069] If the multiple protrusions 10 are arranged on the outer circumferential surface of the insert member 1 such that adjacent protrusions 10 are spaced apart appropriately, the aluminum alloy poured into the mold will spread suitably between the multiple protrusions 10. As a result, it is possible to suppress gaps that arise between the motor case and the insert member 1, improving the bonding strength between the motor case and the insert member 1. In particular, even in a motor case manufactured by gravity casting, which is considered to have difficulty in spreading the aluminum alloy to every corner, the aluminum alloy will easily spread between the protrusions on the outer circumferential surface of the insert member 1.

[0070] In addition, the insert member 1 is firmly fixed to the motor case in the axial, circumferential and radial directions. This makes it possible to suppress the displacement of the stator in each direction even when the inner circumference of the insert member 1 is machined to form a stator holder and a stator is fitted to the inner circumference 40 and the motor is operated. As a result, it is expected that the reliability, durability and continuous operating time of the motor will be improved, and loss will be reduced and performance will be improved by reducing friction.

[0071] The insert member 1 of the present invention can maintain the bonding strength between the motor case and the insert member 1, and therefore can prevent misalignment or the occurrence of small gaps between the insert member 1 and the motor case. Furthermore, by preventing such misalignment and gaps during operation of the motor, it is possible to prevent the surfaces in the gap from being struck by micro-vibrations, causing wear and reducing the durability of the motor itself.

[0072] Although the embodiments of the present invention have been described above, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. [Explanation of symbols]

[0073] 1: Insert parts for rotating electrical machines 10:Protrusion 20: Line segment 30: Concentrated protrusions C: Central axis of insert

Claims

1. A generally cylindrical insert member that is cast into an aluminum alloy motor case of a rotating electrical machine, A plurality of protrusions are formed on the outer peripheral surface of the insert member, in a cross section, which is one of the cut surfaces appearing on either side of the central axis when the insert member is cut axially into two parts by a virtual plane including the central axis of the insert member, the insert member defines, within a predetermined axial length range, a solid region where the protrusion overlaps with a line segment parallel to an inner peripheral surface of the insert member, and a non-solid region where the protrusion does not overlap with the line segment, A value indicating a ratio of the solid portion region within a range of the length in the predetermined axial direction on the line segment is defined as a solid portion ratio, In the entire cross section of the insert member, the line segment is moved from the tip end of the protrusion toward the base end side along the height direction of the protrusion at a predetermined pitch, and the values ​​of the solid portion ratio at each measurement point are plotted in order, and a diagram in which the horizontal axis represents the solid portion ratio and the vertical axis represents the distance from the tip end in the height direction as a measurement height is defined as a solid portion summary diagram, The average of the solid part ratios at the measurement points obtained from the plurality of cross sections is defined as an average solid part ratio, and the solid part summary chart on which the average solid part ratios are plotted is defined as an average solid part summary chart; In the average solid portion summary diagram, the position where the average solid portion ratio is 0 is defined as the tip portion on the diagram, and the position where the average solid portion ratio plotted in sequence from the tip portion side to the base portion side first exceeds 0.98 is defined as the base portion on the diagram, When the distance from the tip end to the base end is defined as the average maximum height of the protrusion, the average maximum height of the protrusion is 0.08% or more of the outer diameter of the insert member. Insert material for rotating electrical machines.

2. The average maximum height of the protrusions is within a range of 0.08% to 1% of the outer diameter of the insert member. The insert member for a rotating electrical machine according to claim 1 .

3. In the average solid part summary chart, In the range from the center position of the average maximum height of the protrusions to the tip on the figure, the sum of the average solid part ratios excluding the position of the tip on the figure, In the range from the central position of the average maximum height of the protrusions to the base end on the figure, the total value of the average solid portion ratio excluding the position of the base end on the figure is larger. The insert member for a rotating electrical machine according to claim 1 .

4. Two or more measurement points plotted on the average solid part summary chart, The two or more measurement points are included within a range in which the difference in the average solid part ratio between the two or more measurement points is 0.10 or less and the difference in the measurement height between the two or more measurement points is 0.05 mm or more. The insert member for a rotating electrical machine according to claim 1 .

5. The average solid part ratios plotted on the average solid part summary chart are The average solid part ratio has a maximum peak and the average solid part ratio has a minimum peak, The position of the maximum peak appears on the tip side of the figure relative to the position of the minimum peak. The insert member for a rotating electrical machine according to claim 1 .

6. In the average solid part summary chart, The average solid part ratio value at the minimum peak is 0.08 or more; The insert member for a rotating electrical machine according to claim 5 .

7. In the average solid part summary chart, a difference between the average solid part ratio value at the maximum peak and the average solid part ratio value at the minimum peak is 0.02 or more and 0.20 or less; The insert member for a rotating electrical machine according to claim 5 .

8. In the average solid part summary chart, The average solid part ratio value at the maximum peak is 0.50 or less; The insert member for a rotating electrical machine according to claim 5 .

9. On the outer circumferential surface of the insert member, The protrusion is formed only in a partial area of ​​the outer circumferential surface. The insert member for a rotating electrical machine according to claim 1 .

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