Inspection method, manufacturing method, and measuring device

Abstract

This inspection method is for inspecting the orientation of a magnet body (10) integrally having a plurality of magnet pieces (11-13) having mutually different orientations. This inspection method includes: measuring surface magnetic flux at a plurality of measurement positions of a permanent magnet body; and calculating the orientation of each of the magnet pieces (11-13) on the basis of measurement data from the number of measurement positions equal to the total number of magnet pieces (11-13) included in the magnet body (10).

Description

Inspection Method, Manufacturing Method, and Measuring Device Cross - reference to Related Applications

[0001] This application is based on Japanese Patent Application No. 2024 - 166555 filed in Japan on September 25, 2024, and the content of the base application is incorporated herein by reference in its entirety.

[0002] The disclosure according to this specification relates to a technique for inspecting the orientation of a permanent magnet body.

[0003] Patent Document 1 discloses a technique in which the magnetic flux density distribution on the outer peripheral surface of a permanent magnet body is measured, and the orientation of the easy magnetization axis is designed based on the magnetic flux density distribution.

[0004] Japanese Unexamined Patent Application Publication No. 2015 - 153790

[0005] Here, it is understood that the magnetic flux density distribution includes data of surface magnetic fluxes at a large number of measurement positions. For example, when obtaining the orientation by solving equations for each measurement position, since the total number of equations becomes larger than the total number of variables indicating the orientation, there is a concern that the solution cannot be uniquely determined and it becomes difficult to evaluate the orientation state. Also, since the amount of data to be processed increases, the time required for processing becomes longer. Therefore, the orientation calculation of the permanent magnet body based on the magnetic flux density distribution is considered to have room for improvement as a method for inspecting permanent magnets.

[0006] The object of the disclosure of this specification is to provide an inspection method for more appropriately inspecting the orientation of a permanent magnet body, a manufacturing method using an appropriate inspection, and a measuring device for realizing an appropriate inspection.

[0007] One of the aspects disclosed herein is an inspection method for inspecting the orientation of a permanent magnet body integrally having a plurality of magnet pieces having different orientations from each other, including measuring surface magnetic fluxes at a plurality of measurement positions of the permanent magnet body, and calculating the orientation of each magnet piece based on the measurement data at the number of measurement positions equal to the total number of magnet pieces included in the permanent magnet body.

[0008] Another aspect of the embodiments disclosed herein is a manufacturing method for a permanent magnet body, comprising: connecting a plurality of magnet pieces having different orientations to form a permanent magnet body having a plurality of magnet pieces integrally; and calculating the orientation of each magnet piece based on measurement data from a number of measurement positions equal to the total number of magnet pieces contained in the permanent magnet body, and inspecting the orientation of the permanent magnet body.

[0009] In this embodiment, the orientation calculation of multiple magnet pieces integrally attached to a permanent magnet body is performed based on measurement data from a number of measurement positions equal to the total number of these magnet pieces. That is, the total number of variables indicating orientation can be matched with the total number of equations obtained for each measurement position, so that the solution to the orientation can be uniquely determined. In addition, the amount of data and time required for processing the orientation calculation can be reduced. Therefore, the orientation of the permanent magnet body can be inspected more appropriately. This embodiment is particularly suitable for inspections performed during manufacturing in factories and the like.

[0010] Another embodiment disclosed herein is a measuring device for performing a measurement, comprising a measuring unit configured to measure magnetic flux, wherein the measuring unit is configured to output to a computer signals indicating surface magnetic flux measured at a number of measuring positions equal to the total number of magnet pieces, in order to inspect the orientation of a permanent magnet body having a plurality of magnet pieces integrally having different orientation states.

[0011] In this configuration, signals indicating the surface magnetic flux measured at a number of measurement positions equal to the total number of magnet pieces integrally attached to the permanent magnet body are output to the computer. That is, when the computer calculates the orientation of each magnet piece for orientation inspection, the total number of variables indicating orientation can be matched with the total number of equations obtained for each measurement position, thereby uniquely determining the solution for orientation. Furthermore, the amount of data and processing time for orientation calculations can be reduced. Therefore, the orientation of the permanent magnet body can be inspected more appropriately.

[0012] The symbols in parentheses included in the claims, etc., are illustrative examples illustrating the correspondence with the embodiments described later, and are not intended to limit the technical scope.

[0013] A perspective view showing the rotor's appearance. A diagram showing multiple permanent magnets assembled to the rotor. A diagram showing the appearance of the permanent magnets. A flowchart illustrating the manufacturing method. A schematic diagram showing the measuring device. A side view showing the measuring unit. A diagram showing the functional configuration of the computer. A diagram explaining the dimensional data for generating the analysis model. A diagram explaining the analysis model. A flowchart illustrating the inspection method.

[0014] In the scope of this disclosure or claims, the term "processor" means one or more hardware processors configured to execute processing defined by computer program code (i.e., one or more instructions of a computer program) contained in a computer program, by reading the code each time. In other words, a "processor" is a hardware device that executes one or more programmed processes. Therefore, computer program code can also be considered software that can define the processing of the processor according to its content. For example, a "processor" may be a general-purpose or specific-purpose processor and may be, but is not limited to, a CPU, microprocessor, GPU, and DFP (Data Flow Processor).

[0015] In the scope of this disclosure or claims, the term “memory” refers to one or more hardware memories that are non-transitional tangible recording media configured to record computer program code and / or data in a manner accessible by a processor. “Memory” can be implemented by memory technologies such as SRAM, SDRAM, non-volatile flash memory, or other types of memory. The computer program code that constitutes the program is recorded in memory and executed by the processor, thereby enabling the processor to perform the various functions described above.

[0016] In this disclosure or claims, the term “circuit” refers to one or more logic circuits as hardware, configured to perform specific processing based on a pre-designed circuit configuration. In other words (and, in contrast to “processor”), “circuit” in this disclosure or claims refers to hardware devices that perform specific processing based on a circuit configuration, rather than processing defined by software such as the computer program code described above. For example, “circuit” may include custom ICs such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) designed with a Hardware Description Language (HDL). That is, “circuit” in this disclosure or claims includes all hardware circuits except for the processor described above, which performs processing by reading computer program code.

[0017] In the scope of this disclosure or claims, the expression “at least one circuit and processor” should be interpreted as a disjunctive (logical OR) and not as at least one circuit and at least one processor.

[0018] In this disclosure or claims, the term “processing unit” means a hardware device that performs processing by a “processor,” “circuit,” or a combination thereof. “Processing unit” may also mean the “processor” itself if its function is not achievable by the “circuit” but is achievable by the “processor.”

[0019] One embodiment will be described below with reference to the drawings.

[0020] (First Embodiment) The inspection method and manufacturing method according to the first embodiment are applied to a permanent magnet body (hereinafter referred to as "magnet body") 10. The magnet body 10 may be, for example, a samarium-cobalt magnet, or it may be any other type of magnet. The magnet body 10 is used as a propulsion motor for a mobile body. Here, the mobile body may be a manned aircraft, an electric vehicle (EV), or other vehicle, and the motor may be a motor with an output of several tens of kilowatts to several hundred kilowatts used in these mobile bodies. The manned aircraft may be, for example, a vertical take-off and landing eVTOL (Electronic Vertical Take-Off and Landing aircraft), and may be configured to rotate its propellers using the power of the motor. The mobile body may also be an unmanned aircraft such as a drone, and the motor may be a small motor used in a drone.

[0021] The magnet body 10 is assembled to the rotor 1 of the propulsion motor shown in Figure 1. The rotor 1 has a substantially cylindrical hollow structure. As shown in Figure 2, the rotor 1 has a housing space capable of accommodating the magnet body 10 between the cylindrical outer wall 1a and the cylindrical inner wall 1b. Multiple magnet bodies 10, which are substantially identical in shape and substantially identical in orientation, are arranged in the housing space. More specifically, the multiple magnet bodies 10 are arranged along the circumferential direction D2 of the rotor 1 with substantially no gaps between them, extending over the entire circumference.

[0022] As shown in Figure 3, the magnet body 10 integrally comprises a plurality of magnet pieces 11 to 13 having different orientations from each other. For example, the total number of magnet pieces 11 to 13 is three. The three magnet pieces 11 to 13 are arranged in a line, assuming they are aligned along the circumferential direction D2. Each magnet piece 11 to 13 is bonded to the adjacent magnet piece via adhesive layers 14 and 15 (see also Figure 8). The adhesive layers 14 and 15 may be formed by applying a liquid adhesive to the magnet pieces 11 to 13 and allowing it to harden. The adhesive layers 14 and 15 may be composed of adhesive films, adhesive sheets, etc.

[0023] The orientation (in other words, the direction of the magnetic poles) of each magnet piece 11 to 13 may be configured to form a Halbach arrangement. For example, the two magnet pieces 11 and 13 at both ends of the three magnet pieces 11 to 13 are oriented so that magnetic flux is generated in the radial direction D1 of the rotor 1. The central magnet piece 12 of the three magnet pieces 11 to 13 is oriented so that magnetic flux is generated in the circumferential direction D2, which is perpendicular to the radial direction D1.

[0024] The central magnet piece 12 is formed in a partially cylindrical shape. That is, the cross-section of the magnet piece 12 including the circumferential direction D2 and the radial direction D1 is substantially the same at any position of the cut surface and is formed in a partially annular shape. When the diameter of the rotor 1 is large, this cross-section may be substantially square in shape. The cross-section of the magnet piece 12 including the axial direction D3 and the radial direction D1 is substantially the same at any position of the cut surface and is rectangular. The surface of the central magnet piece 12 that is in contact with the adhesive layers 14 and 15 is formed in a planar shape.

[0025] In contrast, the magnet pieces 11 and 13 at both ends are formed in a more complex shape than the magnet piece 12 in the center. Here, the complexity of the shape is defined by the number of elements in the figure. The number of elements is the number of lines, angles, and faces. For example, the total number of lines, angles, and faces of magnet pieces 11 and 13 is 27, while the total number of lines, angles, and faces of magnet piece 12 is 22, so it can be said that magnet pieces 11 and 13 have a more complex shape.

[0026] Specifically, the cross-sections of the magnet pieces 11 and 13 that include the circumferential direction D2 and radial direction D1 of the rotor 1 are substantially the same at any cutting position, but have a roughly pentagonal shape as if a part of a partial ring had been cut. As a result, the cross-sections of the magnet pieces 11 and 13 that include the axial direction D3 and radial direction D1 are rectangular, but have different shapes depending on the cutting position. The surfaces of the magnet pieces 11 and 13 at both ends that are in contact with the adhesive layers 14 and 15 are formed in a planar shape and are substantially the same shape as the surface of the central magnet piece 12.

[0027] Furthermore, the magnetic pieces 11 and 13 at both ends have an inverted shape, as if they are inverted relative to each other with the central magnetic piece 12 in between. In this way, each magnetic piece 11 and 13 may be configured with a different shape from the others.

[0028] Such a magnet body 10 or rotor 1 including the magnet body 10 is manufactured by a manufacturing method as shown in the flowchart of Figure 4, for example. In step S10, each magnet piece 11 to 13 is formed into a predetermined shape and bonded together. In step S20, following step S10, each magnet piece 11 to 13 is magnetized using a magnetization device to form the magnet body 10.

[0029] In step S30, following step S20, the surface magnetic flux and dimensions of the magnet body 10 are measured using the measuring device 20. In step S40, following step S30, the orientation angles of each magnet piece 11 to 13 are calculated and inspected. Steps S30 and S40 may be collectively referred to as the inspection process or inspection method. If the measuring device 20 has the function of step S40, the measuring device 20 may be referred to as the inspection device. By passing through the inspection process, the magnet body 10 is completed as a product.

[0030] The inspection of the magnets 10 may be a 100% inspection or a sampling inspection. For example, if the magnets 10 are used in a manned aircraft, a 100% inspection may be performed. On the other hand, if the magnets 10 are used in a vehicle or an unmanned aircraft, a sampling inspection may be performed.

[0031] In step S50, following step S40, the multiple magnets 10 that have passed the inspection process are assembled onto the rotor 1. With this, the rotor 1 is completed as a product, and the series of processes is finished.

[0032] Next, the details of the inspection process (inspection method) will be explained. The inspection uses the measuring device 20 shown in Figure 5. The measuring device 20 consists of a measuring unit 30 and a computer 40.

[0033] The measurement unit 30 is a unit for measuring the surface magnetic flux of the magnet body 10. The measurement unit 30 includes a fixing jig 31 and a magnetic flux probe 36.

[0034] The fixing jig 31 is made of a rigid, non-magnetic material. The non-magnetic material here is, for example, brass, but stainless steel or a resin material other than metal may also be used. As shown in Figure 6, the fixing jig 31 has a flat plate portion 32 and a base portion 33. The flat plate portion 32 is formed in a flat shape and supports the base portion 33. The base portion 33 has a mounting base portion 33a on which the magnet body 10 is placed. Along with this, the base portion 33 has a pair of holding walls 33b, 33c that contact both ends of the magnet body 10 in the arrangement direction in which the magnet pieces 11 to 13 are arranged, and that hold the magnet body 10 in a fixed position. The base portion 33 is configured such that the top and sides of the magnet body 10 are open when the magnet body 10 is held in a fixed position.

[0035] The magnetic flux probe 36 is formed in a substantially rod shape. The magnetic flux probe 36 has a measuring end in which a Hall element 37, which functions as a magnetic flux sensor element, is embedded. The magnetic flux probe 36 is capable of outputting the voltage change generated in the Hall element 37 as an electrical signal (hereinafter referred to as a probe signal) to the computer 40. Therefore, by moving the magnetic flux probe 36 to the position where the surface magnetic flux of the magnet body 10 is to be measured, the surface magnetic flux of the magnet body 10 can be measured. The magnetic flux probe 36 may be configured so that its position can be controlled by the computer 40.

[0036] As shown in Figure 5, the computer 40 has at least one CPU (Central Processing Unit) 41 and at least one memory 42. The memory 42 may be a non-transitory tangible storage medium that non-temporarily stores computer programs, data, etc. that can be read by the CPU 41. Furthermore, the computer 40 may have a rewritable volatile storage medium such as RAM (Random Access Memory) 43. The CPU 41 can execute various processes according to the computer programs stored in the memory 42.

[0037] Furthermore, the computer 40 includes an interface 44 for exchanging data with the outside world. The interface 44 may include a communication interface for connecting the computer 40 to the measurement unit 30, the internet, and external devices. The interface 44 may include an operation interface such as a keyboard or mouse for accepting operations from a human (e.g., a factory inspector).

[0038] Furthermore, the computer 40 may include a display 45. The display 45 may be a liquid crystal display or an OLED display that displays the processing results of the computer 40 as an image. The display 45 may also be a projection-type display such as a projector.

[0039] As shown in Figure 7, the computer 40 includes an analysis model generation unit F1, a magnetic flux measurement unit F2, an orientation angle calculation unit F3, and a quality determination unit F4, as functional units whose functions are realized when the CPU 41 executes a computer program stored in the memory 42.

[0040] The analysis model generation unit F1 acquires dimensional data of the magnet body 10 and generates an analysis model based on the dimensional data. The dimensional data may be actual measurement data obtained by actually measuring the dimensions of the magnet body 10 to be inspected, or it may be design data that records the design dimensions of the magnet body 10. If the dimensional data is actual measurement data, it may be data that an inspector has measured and manually entered into the computer 40 through the interface 44 (especially the operation interface), or it may be data that the computer 40 has automatically measured by controlling a separately prepared dimensional measuring device. The measuring device 20 may also have a function to measure dimensions.

[0041] As shown in Figure 8, the dimensional data may include the coordinates of the corners of each magnet piece 11 to 13. By including the coordinates of the corners of the magnet pieces 11 to 13 that face each other across the adhesive layers 14 and 15, the dimensional data may substantially include the thickness dimensions of the adhesive layers 14 and 15.

[0042] Then, when the analysis model generation unit F1 acquires the dimensional data as shown in FIG. 8, it stores the dimensional data in the memory 42 in advance. Then, based on the dimensional data, the analysis model generation unit F1 generates a model showing the positional relationship of the portions of the magnet body 10 made of the magnetic material. That is, as shown in FIG. 9, the analysis model shows the regions X1, X2, X3 occupied by the respective magnet pieces 11 to 13 with the adhesive layers 14 and 15 excluded. In other words, the analysis model is a model showing the regions X1, X2, X3 occupied by the magnetic materials having the same orientation, respectively.

[0043] In FIGS. 8 and 9, the thickness dimensions of the adhesive layers 14 and 15 are exaggerated and shown larger. Also, in FIGS. 8 and 9, the coordinates are represented two-dimensionally and the analysis model is also shown two-dimensionally, but in actuality, it may be represented three-dimensionally.

[0044] The magnetic flux measurement unit F2 controls the position of the magnetic flux probe 36 and moves it to the necessary measurement position. Then, the magnetic flux measurement unit F2 receives the probe signal from the magnetic flux probe 36 at the measurement position and measures the surface magnetic flux of the magnet body 10 at the measurement position. The magnetic flux measurement unit F2 generates measurement data associating the coordinates of the measurement position with the measurement result of the surface magnetic flux at the measurement position. The magnetic flux measurement unit F2 stores the measurement data in the memory 42.

[0045] The magnetic flux measurement unit F2 sequentially moves the position of the electromagnetic probe to measure the surface magnetic flux at the number of measurement positions equal to the total number of the magnet pieces 11 to 13 included in the magnet body 10, and performs the measurement. In this embodiment, since the total number of the magnet pieces 11 to 13 is three, the measurement is performed at three measurement positions.

[0046] The orientation angle calculation unit F3 calculates the orientation angles of the respective magnet pieces 11 to 13 based on the measurement data measured at the number of measurement positions equal to the total number of the magnet pieces 11 to 13. Here, the orientation angle is an angle indicating the direction of the magnetic pole. For example, the orientation angle calculation unit F3 applies the Biot-Savart law to the analysis model and formulates an equation showing the relationship between the orientation of each of the magnet pieces 11 to 13 and the magnetic flux at the measurement position for each measurement position. As the magnetic flux for each measurement position here, the measurement data stored in the memory 42 is used.

[0047] Since the number of measurement positions used in the calculation is equal to the total number of the magnetic pieces 11 to 13, the number of equations to be set up is equal to the total number of the magnetic pieces 11 to 13. And since the number of orientation angles to be solved is also equal to the total number of the magnetic pieces 11 to 13, by solving the equations equal to the total number of the magnetic pieces 11 to 13 as simultaneous equations, the orientation angles of each of the magnetic pieces 11 to 13 can be obtained as uniquely determined solutions.

[0048] The pass / fail determination unit F4 determines whether the orientation angles of each of the magnetic pieces 11 to 13 fall within an allowable range (hereinafter referred to as tolerance). When the orientation angles of the magnetic pieces 11 to 13 are within the tolerance respectively, the magnetic body 10 is determined to be a good product, and otherwise, the magnetic body 10 is determined to be a defective product. The tolerance may be preset based on the application or function of the propulsion motor for which the magnetic body 10 is used.

[0049] Next, an example of a method of performing measurement or inspection using the apparatus 20 will be described using the flowchart of FIG. 10. Steps S101 to S104 of this flowchart may be realized by the CPU 41 executing a computer program stored in the memory 42.

[0050] In step S101, the analysis model generation unit F1 acquires the dimensional data of the magnetic body 10 and generates an analysis model from the dimensional data. In step S102 after step S101, the magnetic flux measurement unit F2 controls the magnetic flux probe 36 and sequentially measures the surface magnetic fluxes at the same number of measurement positions as the total number of the magnetic pieces 11 to 13 included in the magnetic body 10, and generates measurement data.

[0051] In step S103 after step S102, the orientation angle calculation unit F3 calculates the orientation angles of each of the magnetic pieces 11 to 13 based on the measurement data of the surface magnetic fluxes at the same number of measurement positions as the total number of the magnetic pieces 11 to 13. In step S104 after step S103, the pass / fail determination unit F4 performs a pass / fail determination of the magnetic body 10. Thus, the measurement or inspection of the magnetic body 10 is completed.

[0052] According to the first embodiment described above, the orientation calculation of the multiple magnet pieces 11 to 13 integrally provided on the magnet body 10 is performed based on measurement data from a number of measurement positions equal to the total number of these magnet pieces 11 to 13. That is, the total number of variables indicating orientation can be matched with the total number of equations obtained for each measurement position, so that the solution to the orientation can be uniquely determined. In addition, the amount of data and time required for processing the orientation calculation can be reduced. Therefore, the orientation of the magnet body 10 can be inspected more appropriately. This orientation calculation is particularly suitable for inspections performed during manufacturing in factories, etc.

[0053] Furthermore, according to the first embodiment, the measurement is performed with the magnet body 10 fixedly held by a fixing jig 31 made of a non-magnetic material. By making the fixing jig 31 of a non-magnetic material that does not easily affect the measurement of surface magnetic flux, the measurement accuracy is improved. Therefore, it becomes possible to inspect the orientation of the magnet body 10 more appropriately.

[0054] Furthermore, according to the first embodiment, multiple magnet pieces 11 to 13 are connected via adhesive layers 14 and 15. Measured data of the dimensions of the magnet pieces 11 to 13, including the adhesive layers 14 and 15, is obtained and used for orientation calculations. By using measured values ​​of the dimensions of the adhesive layers 14 and 15, which are prone to dimensional variations and where incorrect dimensions can easily lead to errors in orientation calculations, the accuracy of the calculated orientation is improved.

[0055] Furthermore, according to the first embodiment, at least some of the magnet pieces 11 to 13 are formed in a more complex shape than some of the other magnet pieces 12. Under conditions where the magnet pieces 11 to 13 have different and complex shapes, if data from a large number of measurement positions is used for orientation calculation, the processing load becomes extremely high. In this embodiment, which employs a number of measurement positions equal to the total number of magnet pieces 11 to 13, this concern is resolved, and the orientation can be inspected more appropriately.

[0056] Furthermore, according to the first embodiment, the magnet body 10 is used in the rotor 1 of the propulsion motor for the mobile body. Motor efficiency is of utmost importance in the propulsion of a mobile body. For this reason, it is important to be able to properly inspect the orientation during the manufacturing process.

[0057] Furthermore, according to the first embodiment, the magnet body 10 is formed to include magnet pieces 11 and 13 oriented along the radial direction D1 of the rotor 1, and magnet piece 12 oriented along the circumferential direction D2 of the rotor 1. In addition, the plurality of magnet pieces 12 form a Halbach arrangement. With this configuration, it is possible to appropriately perform orientation calculations for the magnet body 10, where the orientation differs for each of the magnet pieces 11 to 13.

[0058] Furthermore, according to the first embodiment, the surface magnetic flux of the magnet body 10 is measured before the magnet body 10 is assembled to the rotor 1. Since the material of the rotor 1 and the orientation measurement do not affect each other, the accuracy of the calculated orientation is increased, and the restriction on the design freedom of the rotor 1 material can be suppressed.

[0059] Furthermore, in the measuring device 20 of the first embodiment, signals indicating the surface magnetic flux measured at a number of measurement positions equal to the total number of magnet pieces 11 to 13 integrally provided on the magnet body 10 are output to the computer 40. That is, when the computer 40 calculates the orientation of each magnet piece 11 to 13 for orientation inspection, the total number of variables indicating orientation can be matched with the total number of equations obtained for each measurement position, so that the solution for orientation can be uniquely determined. In addition, the amount of data and time required for processing the orientation calculation can be reduced. Therefore, the orientation of the magnet body 10 can be inspected more appropriately.

[0060] Furthermore, according to the first embodiment, the computer 40 has a memory 42 that stores dimensional data relating to the dimensions of each magnet piece 11 to 13. The computer 40 then calculates the orientation of each magnet piece based on the stored dimensional data and measurement data obtained from the signals. By storing the data in the memory 42, it becomes possible to input the dimensional data into the computer 40 in advance before measurement.

[0061] (Other Embodiments) Although one embodiment has been described above, this disclosure is not limited to that embodiment and can be applied to various embodiments without departing from the gist of this disclosure.

[0062] In another embodiment, the magnetic body may be formed by integrally connecting four or more magnetic pieces. The magnetic pieces do not have to be arranged in a single row, may be arranged in multiple rows, or may be arranged in two dimensions.

[0063] In another embodiment, the magnetic pieces may be the same shape as each other.

[0064] In other embodiments, at least part of the formation of the magnet pieces, the formation of the magnet body, the inspection of the magnet body, and the assembly of the magnet body to the rotor (manufacturing of the rotor) may be carried out by another entity.

[0065] In another embodiment, if the surface magnetic flux is measured at multiple measurement positions on the magnet body, the surface magnetic flux may be measured at more measurement positions than the total number of magnet pieces. In this case as well, the orientation calculation may be performed using data from a number of measurement positions equal to the total number of magnet pieces from among the data from many measurement positions.

[0066] In another embodiment, the measuring device 20 may be configured in a way that does not allow for control of the position of the magnetic flux probe 36. For example, the movement of the magnetic flux probe 36 to the measurement position does not have to be performed by automatic control, but may be performed manually by an inspector.

[0067] In another embodiment, the measuring device 20 may include a measuring unit 30 but not a computer 40. The computer 40 may be located in a remote location relative to the measuring device 20. The computer 40 may be a portable terminal such as a tablet or smartphone. In this case, the measuring device 20 may be connected to the internet using Wi-Fi® or the like, or it may output and transmit a probe signal or a signal of measurement data indicating the measurement result of magnetic flux processed therefrom to the computer 40 using short-range wireless communication such as Bluetooth®.

[0068] In another embodiment, the computer 40 may include another type of processor (e.g., a GPU) in place of or together with the CPU 41. The computer 40 may also have circuits such as an FPGA, and may use such circuits for at least part of the orientation calculation.

[0069] (Disclosure of Technical Ideas) This specification discloses several technical ideas as described in the following paragraphs. Some paragraphs are written in a multiple dependent form, where subsequent paragraphs alternately refer to preceding paragraphs. These paragraphs written in a multiple dependent form define several technical ideas.

[0070] <Technical Concept 1> An inspection method for inspecting the orientation of a permanent magnet body (10) integrally having a plurality of magnet pieces (11 to 13) having different orientations from each other, the inspection method comprising: measuring the surface magnetic flux at a plurality of measurement positions of the permanent magnet body; and calculating the orientation of each magnet piece based on measurement data from a number of measurement positions equal to the total number of magnet pieces contained in the permanent magnet body.

[0071] <Technical Concept 2> The inspection method according to Technical Concept 1, wherein the surface magnetic flux is measured while the permanent magnet body is fixedly held by a jig (31) made of a non-magnetic material.

[0072] <Technical Idea 3> The inspection method according to technical idea 1 or 2, wherein a plurality of the magnet pieces are connected via adhesive layers (14, 15), and further includes obtaining measured data of the dimensions of the magnet pieces including the adhesive layers, and using the measured data in calculating the orientation.

[0073] <Technical Idea 4> A manufacturing method for a permanent magnet body (10), comprising: connecting a plurality of magnet pieces (11 to 13) having different orientations to form a permanent magnet body having a plurality of the magnet pieces integrally; and calculating the orientation of each of the magnet pieces based on measurement data of a number of measurement positions equal to the total number of magnet pieces included in the permanent magnet body, and inspecting the orientation of the permanent magnet body.

[0074] <Technical Idea 5> The manufacturing method according to Technical Idea 4, wherein at least some of the multiple magnet pieces (11, 13) are formed in a more complex shape than some of the other magnet pieces (12).

[0075] <Technical Idea 6> The manufacturing method described in Technical Idea 4 or 5, wherein the permanent magnet body is used in the rotor (1) of a propulsion motor for a mobile body.

[0076] <Technical Idea 7> The manufacturing method according to Technical Idea 6, wherein the permanent magnet body is formed such that the permanent magnet body includes the magnet pieces (11, 13) having an orientation along the radial direction (D1) of the rotor and the magnet piece (12) having an orientation along the circumferential direction (D2) of the rotor.

[0077] <Technical Idea 8> The manufacturing method according to technical idea 6 or 7, wherein the permanent magnet body is formed such that a plurality of the magnet pieces form a Halbach arrangement.

[0078] <Technical Idea 9> The manufacturing method according to any one of technical ideas 6 to 8, wherein the inspection includes measuring the surface magnetic flux of the permanent magnet body before it is assembled to the rotor.

[0079] <Technical Concept 10> A measuring device for performing measurements, comprising: a measuring unit (30) configured to measure surface magnetic flux, wherein the measuring unit is configured to output signals indicating surface magnetic flux measured at a number of measurement positions equal to the total number of magnet pieces (11 to 13) to a computer (40) in order to inspect the orientation of a permanent magnet body (10) integrally having a plurality of magnet pieces (11 to 13) having different orientation states to a computer (40).

[0080] <Technical Concept 11> The measuring device according to technical concept 10, wherein the measuring unit is made of a non-magnetic material and has a jig (31) for fixedly holding the permanent magnet body.

[0081] <Technical Concept 12> The measuring device according to technical concept 10 or 11, further comprising the computer, wherein the computer has a memory (42) for storing dimensional data relating to the dimensions of each of the magnet pieces, and calculates the orientation of each of the magnet pieces based on the stored dimensional data and measurement data obtained from the signals.

Claims

1. An inspection method for inspecting the orientation of a permanent magnet body (10) integrally having a plurality of magnet pieces (11 to 13) having different orientations from each other, the inspection method comprising: measuring the surface magnetic flux at a plurality of measurement positions of the permanent magnet body; and calculating the orientation of each magnet piece based on measurement data from a number of measurement positions equal to the total number of magnet pieces contained in the permanent magnet body.

2. The inspection method according to claim 1, wherein the surface magnetic flux is measured while the permanent magnet body is fixedly held by a jig (31) made of a non-magnetic material.

3. The inspection method according to claim 1, wherein the plurality of magnet pieces are connected via adhesive layers (14, 15), and further comprises obtaining measured data of the dimensions of the magnet pieces including the adhesive layers, and using the measured data in calculating the orientation.

4. A manufacturing method for a permanent magnet body (10), comprising: connecting a plurality of magnet pieces (11 to 13) having different orientations from each other to form a permanent magnet body having a plurality of the magnet pieces integrally; and calculating the orientation of each magnet piece based on measurement data of a number of measurement positions equal to the total number of magnet pieces contained in the permanent magnet body, and inspecting the orientation of the permanent magnet body.

5. The manufacturing method according to claim 4, wherein at least some of the plurality of magnet pieces (11, 13) are formed in a more complex shape than some of the other magnet pieces (12).

6. The manufacturing method according to claim 4, wherein the permanent magnet body is used in the rotor (1) of a propulsion motor for a mobile body.

7. The manufacturing method according to claim 6, wherein the permanent magnet body is formed such that it includes the magnet pieces (11, 13) having an orientation along the radial direction (D1) of the rotor and the magnet piece (12) having an orientation along the circumferential direction (D2) of the rotor.

8. The manufacturing method according to claim 7, wherein the permanent magnet body is formed such that the plurality of magnet pieces form a Halbach arrangement.

9. The manufacturing method according to claim 6, wherein the inspection includes measuring the surface magnetic flux of the permanent magnet body before the permanent magnet body is assembled to the rotor.

10. A measuring device for performing measurements, comprising a measuring unit (30) configured to measure surface magnetic flux, wherein the measuring unit is configured to output signals indicating surface magnetic flux measured at a number of measurement positions equal to the total number of magnet pieces (11 to 13) to a computer (40) in order to inspect the orientation of a permanent magnet body (10) integrally having a plurality of magnet pieces (11 to 13) having different orientation states from each other.

11. The measuring device according to claim 10, wherein the measuring unit is made of a non-magnetic material and includes a jig (31) for fixedly holding the permanent magnet body.

12. The measuring device according to claim 10, further comprising the computer, wherein the computer has a memory (42) for storing dimensional data relating to the dimensions of each of the magnet pieces, and calculates the orientation of each of the magnet pieces based on the stored dimensional data and measurement data obtained from the signals.

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