Connector and rotating electric machine

Abstract

This linked body is provided with a first member consisting of a powder compression molded body of soft magnetic powder, a second member separate from the first member, and a tapping screw which penetrates through the second member to the first member to link the first member and the second member, wherein: at least the first member, among the first member and the second member, is provided with a pilot hole into which ridge portions of the tapping screw bite, the inner diameter of the pilot hole being at least equal to 83% and at most equal to 95% of the diameter of the ridges of the tapping screw and greater than the diameter of valleys of the tapping screw; and a helical gap surrounded by an outer circumferential surface of the tapping screw and an inner circumferential surface of the pilot hole is provided.

Description

[Technical field]

[0001] The present disclosure relates to a connector and a rotating electric machine. This application claims priority based on Japanese Patent Application No. 2019-089192 filed on May 9, 2019, and incorporates by reference all of the contents of said Japanese application. [Background technology]

[0002] As a rotating electric machine such as an electric motor or a generator, Patent Document 1 discloses an axial gap type rotating electric machine in which a rotor and a stator are arranged facing each other in a direction along the rotation axis of the rotor. The stator used in this rotating electric machine includes an armature core having a back yoke and multiple teeth, and a coil arranged on each tooth.

[0003] The core of Patent Document 1 is a connected body in which teeth and a yoke that are separately manufactured are connected. More specifically, the core is manufactured by fitting columnar convex portions of the teeth and concave portions of the yoke together. In Patent Document 1, the yoke is made of laminated steel plates, and the teeth are made of a powder core that is a powder compact. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2007 / 114079 Summary of the Invention

[0005] The conjugate of the present disclosure is A first member formed of a powder compact of soft magnetic powder; A second member separate from the first member; a tapping screw that penetrates the second member to reach the first member and connects the first member and the second member; Of the first member and the second member, at least the first member has a pilot hole into which a thread portion of the tapping screw bites, The inner diameter of the pilot hole is 83% or more and 95% or less of the diameter of the thread of the tapping screw and is larger than the diameter of the root of the tapping screw, A spiral gap is provided which is surrounded by the outer peripheral surface of the tapping screw and the inner peripheral surface of the pilot hole.

[0006] The rotating electric machine according to the present disclosure comprises: An axial gap type rotating electric machine in which a rotor and a stator are arranged in an axial direction of a rotation shaft of the rotor, Includes the conjugates of the present disclosure. Here, the linker of the present disclosure is any of the following: (1) A coupling body according to the present disclosure, wherein the first member is a tooth used in a core of a rotating electric machine, and the second member is a yoke used in the core. (2) A coupling body according to the present disclosure, wherein the first member is a tooth used in a core of a rotating electric machine, and the second member is a flange portion provided on an end of the tooth. (3) A connected body according to the present disclosure, wherein the first member is a core having teeth and a yoke and used in a rotating electric machine, and the second member is a housing that accommodates the core. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a partial vertical sectional view of an axial gap type rotating electric machine according to a first embodiment. [Diagram 2] FIG. 2 is a schematic perspective view of a stator core provided in the axial gap type rotating electric machine shown in the first embodiment. [Diagram 3] FIG. 3 is a schematic perspective view of a part of the core in FIG. 2, as viewed from the side opposite to the side on which the teeth are provided. [Figure 4] 4 is a partial cross-sectional view taken along the axial direction of the tapping screw in the core of FIG. 2. FIG. [Diagram 5] FIG. 5 is a partially enlarged view of a part of FIG. [Figure 6]FIG. 6 is a photograph showing a cross section of the core of the first embodiment taken along the axial direction of the tapping screw. [Figure 7] FIG. 7 is a partial vertical sectional view of an axial gap type rotating electric machine according to the second embodiment. [Figure 8] FIG. 8 is a partial vertical sectional view of an axial gap type rotating electric machine according to the third embodiment. [Figure 9] FIG. 9 is a partial vertical sectional view of an axial gap type rotating electric machine according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Problem that this disclosure aims to solve] In the configuration of Patent Document 1, the teeth are press-fitted into the recesses of the yoke, or the teeth are fixed to the recesses of the yoke with an adhesive. However, fixing the teeth by press-fitting or by adhesive is cumbersome. Therefore, a coupling body that can be connected with a simpler configuration is desired.

[0009] An object of the present disclosure is to provide a connected body that is connected with a simple configuration and has excellent productivity. Another object of the present disclosure is to provide a rotating electric machine that includes the connected body.

[0010] [Effects of this disclosure] The connected body according to the present disclosure has excellent productivity, and the rotating electric machine according to the present disclosure has excellent productivity.

[0011] [Description of the embodiments of the present disclosure] The present inventors have considered fixing the teeth and yoke of the powder compact with screws. Since the powder compact is fragile, screws are not usually used when fixing the powder compact to another member. This is because cracks and the like occur in the powder compact when a screw hole is machined in the powder compact and when a screw is attached to the screw hole. As a result of their consideration, the present inventors have found a configuration that can solve the above problem. Specifically, the above problem is solved by connecting the first member and the second member with a tapping screw and optimizing the dimensions of the pilot hole into which the tapping screw is attached with respect to the dimensions of the tapping screw.

[0012] The embodiments of the present disclosure are listed and described below.

[0013] <1> The connector according to the embodiment is A first member formed of a powder compact of soft magnetic powder; A second member separate from the first member; a tapping screw that penetrates the second member to reach the first member and connects the first member and the second member; Of the first member and the second member, at least the first member has a pilot hole into which a thread portion of the tapping screw bites, The inner diameter of the pilot hole is 83% or more and 95% or less of the diameter of the thread of the tapping screw and is larger than the diameter of the root of the tapping screw, A spiral gap is provided which is surrounded by the outer peripheral surface of the tapping screw and the inner peripheral surface of the pilot hole.

[0014] The above-mentioned connected body is produced by simply fixing the first member and the second member with a tapping screw. Fixing with a tapping screw is easier than fixing by press fitting or by adhesive. Therefore, the above-mentioned connected body has excellent productivity.

[0015] In the above-mentioned connecting body, the inner diameter of the pilot hole to which the tapping screw is attached is 83% or more of the diameter of the crest of the tapping screw and is larger than the diameter of the root of the tapping screw. If the inner diameter of the pilot hole is 83% or more of the diameter of the crest of the tapping screw, excessive stress is prevented from acting on the pilot hole by the crest of the tapping screw. Furthermore, if the inner diameter of the pilot hole is larger than the diameter of the root of the tapping screw, the pilot hole is not pushed outward in the radial direction by the shank of the tapping screw. Therefore, the connecting body according to the embodiment is less likely to have defects such as cracks. Furthermore, if the inner diameter of the pilot hole is 95% or less of the diameter of the crest of the tapping screw, the tapping screw is less likely to loosen, and the first member and the second member can be firmly fixed.

[0016] <2> As one embodiment of the connector according to the present invention, The second member is formed of a powder compact of soft magnetic powder, The pilot hole may be provided from the first member to the second member.

[0017] In the above configuration, both the first member and the second member are powder compacts of soft magnetic powder. Even in this configuration, the inner diameter of the pilot hole is optimally selected according to the dimensions of the tapping screw, so that cracks are unlikely to occur in the first member and the second member.

[0018] <3> As one embodiment of the connector according to the present invention, In a cross section cut by a plane including the axis of the tapping screw, the area of ​​the gap occupies 45% or more and 65% or less of a predetermined region, The predetermined area is a first straight line connecting an apex of one ridge portion and an apex of another ridge portion adjacent to each other in the direction of the axis; A second straight line including a root of the tapping screw and extending along the root; a third straight line extending from the apex of the one of the peaks in a direction perpendicular to the axis; and a fourth straight line extending from the apex of the other peak portion in a direction perpendicular to the axis.

[0019] If the area of ​​the gap in the specified region is 45% or more and 65% or less, it can be said that the amount of penetration of the tapping screw into the pilot hole is appropriate. Therefore, a connected body in which the area of ​​the gap in the specified region is 45% or more and 65% or less can be said to be a connected body in which the first member and the second member are firmly fixed by the tapping screw. It can also be said to be a connected body in which cracks are unlikely to occur in the powder compact.

[0020] <4> As one embodiment of the connector according to the present invention, The tapping screw may be of type B-0 or type B-1.

[0021] The B-0 type tapping screw is mainly used to fix resin materials. The B-1 type tapping screw is used to fix resin materials and has a groove formed at the tip that acts as a cutting blade. These tapping screws are suitable for fixing powder compacts.

[0022] <5> As one embodiment of the connector according to the present invention, An example of the embodiment is one in which the angle of the threads on the tip side of the tapping screw is smaller than the angle of the threads on the base side.

[0023] The angle of the thread, or the angle of the screw thread, is the angle between the two faces that sandwich the apex of the thread when the tapping screw is cut in the axial direction. In other words, a small angle of the thread means that the thickness of the thread is thin and the thread is sharp. Such a tapping screw is easy to screw into a pilot hole.

[0024] <6> As one embodiment of the connector according to the present invention, The tapping screw may be made of a non-magnetic material.

[0025] When the connecting body is used as a core of a rotating electrical machine, if the tapping screw is made of a non-magnetic material, core loss due to the tapping screw is reduced.

[0026] <7> As one embodiment of the connector according to the present invention, The non-magnetic body may be a resin, a titanium alloy, a brass, an aluminum alloy, a magnesium alloy, or a non-magnetic stainless steel.

[0027] The materials described above provide the strength required for a self-tapping screw.

[0028] <8> As one embodiment of the connector according to the present invention, The tapping screw may be made of a magnetic material.

[0029] When the connecting body is used in the core of a rotating electrical machine, if the tapping screw is made of a magnetic material, a decrease in the torque of the rotating electrical machine due to the tapping screw is suppressed.

[0030] <9> As one embodiment of the connector according to the present invention, The magnetic material may be steel or magnetic stainless steel.

[0031] The materials described above provide the strength required for a self-tapping screw.

[0032] <10> As one embodiment of the connector according to the present invention, An example embodiment is one in which five or more of the ridges are embedded in the pilot hole of the first member.

[0033] In this specification, one crest means a crest for one pitch. When five or more crests are inserted into the pilot hole, the first member and the second member are firmly fixed to each other.

[0034] <11> As one embodiment of the connector according to the present invention, The distance between the bottom of the pilot hole and the tip of the tapping screw may be 0.5 mm or more and 5 mm or less.

[0035] If the distance is 0.5 mm or more, the tip of the tapping screw does not press against the bottom of the pilot hole, thereby suppressing damage to the first member caused by the tip of the tapping screw. Also, if the distance is 5 mm or less, the solid portion of the first member is sufficiently secured, thereby suppressing deterioration of the magnetic properties of the first member.

[0036] <12> As one embodiment of the connector according to the present invention, The inner peripheral surface of the pilot hole may have a tapered shape with an inclination of 1° to 10° with respect to the axis of the pilot hole.

[0037] A pilot hole having a predetermined tapered shape can be provided by molding. For example, a powder compact can be produced using a die equipped with a core for providing the pilot hole. In this case, if the pilot hole has a tapered shape, the core can be easily removed from the powder compact. When a pilot hole is produced in the powder compact by molding, there is no need to machine the powder compact. Therefore, cracks and the like are less likely to occur in the powder compact.

[0038] <13> As one embodiment of the connector according to the present invention, In a cross section cut along a plane including the axis of the tapping screw, the thickness of the first member and the thickness of the second member from the inner surface of the pilot hole in a direction perpendicular to the axis are 2 mm or more.

[0039] In the above-described configuration, the thickness of the first and second members is sufficiently secured on the radially outer side of the pilot hole, so that cracks are unlikely to occur in the first and second members when the first and second members are fastened to each other by the tapping screw.

[0040] <14> As one embodiment of the connector according to the present invention, An example embodiment includes a form in which a filler is disposed in the spiral gap.

[0041] The filler is preferably filled in the pilot hole before fixing with the tapping screw. By disposing the filler in the pilot hole, cracks are less likely to occur in the powder compact when the tapping screw is attached to the pilot hole. This is because friction between the tapping screw and the pilot hole is reduced. In addition, the strength of the powder compact is improved by filling the gap between the inner peripheral surface of the pilot hole and the outer peripheral surface of the tapping screw with the filler.

[0042] <15> As one embodiment of the connector according to the present invention, The head of the tapping screw may be of a countersunk type, a truss type, or a bind type.

[0043] A tapping screw having a head of the above shape is suitable for connecting a first member and a second member.

[0044] <16> As one embodiment of the connector according to the present invention, The first member has a relative density of 90% or more, The second member may be a powder compact of soft magnetic powder, and the relative density of the second member may be 90% or more.

[0045] The relative densities of the first member and the second member are determined by image analysis or the like, as shown in an embodiment described later.

[0046] A powder compact having a relative density of 90% or more has excellent magnetic properties. In addition, a powder compact having a relative density of 90% or more has excellent strength. Therefore, when the first member and the second member are fixed together with a tapping screw, the powder compact is less likely to crack or chip.

[0047] <17> As one embodiment of the connector according to the present invention, the first member is a tooth used in a core of a rotating electric machine, The second member may be a yoke used in the core.

[0048] With the above configuration, the teeth can be easily fixed to the yoke.

[0049] <18> As one embodiment of the connector according to the present invention, the first member is a tooth used in a core of a rotating electric machine, The second member may be a flange portion provided on an end of the tooth.

[0050] In the above configuration, the flange portion can be easily fixed to the teeth.

[0051] <19> As one embodiment of the connector according to the present invention, The first member is a core including teeth and a yoke and used in a rotating electric machine, The second member may be a housing that houses the core.

[0052] In the above-described configuration, the core can be easily fixed to the housing.

[0053] <20> The rotating electric machine according to the embodiment includes: An axial gap type rotating electric machine in which a rotor and a stator are arranged in an axial direction of a rotation shaft of the rotor, the above <17> from <19> The present invention includes any one of the above linked structures.

[0054] The rotating electric machine has excellent productivity because some of the components constituting the rotating electric machine are the connected bodies of the present disclosure, which have excellent productivity.

[0055] [Details of the embodiment of the present disclosure] Specific examples of the connector according to the embodiment of the present disclosure and the rotating electric machine using the connector will be described with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts. Note that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0056] <Embodiment 1> In the first embodiment, a core 30 provided in a rotating electric machine 100 shown in FIG. 1 will be described as a connected body 1 of the present disclosure.

[0057] <Rotating Electric Machine> The rotating electric machine 100 may be a generator or an electric motor such as a motor. The rotating electric machine 100 includes a rotor 2 and a stator 3 disposed in a housing 9. The rotating electric machine 100 of this example is an axial gap type rotating electric machine 100 in which the rotor 2 and the stator 3 are aligned in the direction of the rotation axis of the rotor 2.

[0058] Rotor The rotor 2 includes a plurality of flat magnets 22 and a ring-shaped retaining plate 21 that supports the magnets 22. The retaining plate 21 is fixed to the shaft 20 and rotates together with the shaft 20. The magnets 22 are embedded in the retaining plate 21. The magnets 22 are arranged at intervals in the circumferential direction of the shaft 20. The magnets 22 are magnetized in the direction of the rotation axis of the rotor 2, i.e., in the axial direction of the shaft 20. The magnetization directions of adjacent magnets 22 in the circumferential direction of the shaft 20 are opposite to each other.

[0059] Stator The stator 3 includes a core 30 and a coil 31 arranged on the teeth 4 of the core 30. The rotating electric machine 100 of this example includes two stators 3. An end face of the teeth 4 of one stator 3 faces an end face of the teeth 4 of the other stator 3. Both stators 3, 3 are arranged facing the rotor 2 in the axial direction of the shaft 20 and fixed to the housing 9. Therefore, the rotor 2 is sandwiched between the two stators 3, 3. A bearing 33 is arranged between the stator 3 and the shaft 20, and the stator 3 does not rotate. The core 30 provided in the stator 3 of this example is the connected body 1 of the present disclosure.

[0060] <Core> As shown in Figs. 1 to 3, the core 30, which is the connected body 1 in this example, includes teeth 4 and a yoke 5. The core 30 in this example includes six teeth 4 (Fig. 2). The number of teeth 4 is not particularly limited. When the rotating electric machine 100 is used with three-phase AC, the number of teeth 4 is 3n, where n is a natural number. In this example, the teeth 4 are the first member 11 (Fig. 4), and the yoke 5 is the second member 12 (Fig. 4). The teeth 4 and the yoke 5 are manufactured separately.

[0061] Teeth The teeth 4 in this example are members having a roughly trapezoidal prism shape. The shape of the teeth 4 is not particularly limited. For example, the teeth 4 may be roughly triangular prism-shaped. Alternatively, the teeth 4 may be cylindrical or rectangular prism-shaped. A flange may be provided on the end of the teeth 4 opposite the yoke 5. The flange is a member that protrudes in a direction perpendicular to the protruding direction of the teeth 4, and is provided integrally with the teeth 4.

[0062] The teeth 4 are green compacts formed by compressing and molding soft magnetic powder. The soft magnetic powder is an aggregate of soft magnetic particles. Examples of the soft magnetic powder include at least one powder selected from pure iron having a purity of 99% by mass or more, and iron-based alloys such as Fe-Si-Al alloys, Fe-Si alloys, Fe-Al alloys, and Fe-Ni alloys. Fe is iron, Si is silicon, Al is aluminum, and Ni is nickel. Examples of Fe-Si-Al alloys include sendust, examples of Fe-Si alloys include silicon steel, and examples of Fe-Ni alloys include permalloy. The soft magnetic particles preferably have an insulating coating on their surfaces. By forming an insulating coating on the surfaces of the soft magnetic particles, electrical insulation between the soft magnetic particles can be ensured. Therefore, the iron loss of the teeth 4 caused by eddy current loss is reduced. Examples of the insulating coating include phosphate coating and silica coating.

[0063] The average particle size of the soft magnetic particles is preferably 10 μm or more and 300 μm or less. If the average particle size of the soft magnetic particles is 10 μm or more, the increase in the coercive force and hysteresis loss of the powder compact is suppressed. If the average particle size of the soft magnetic particles is 300 μm or less, the eddy current loss of the powder compact generated in the high frequency range is reduced. More preferably, the average particle size of the soft magnetic particles is 40 μm or more and 260 μm or less. Here, the average particle size refers to the particle size of the particle in which the sum of the masses of the particles with smaller particle sizes in the particle size histogram reaches 50% of the total mass, that is, the 50% particle size.

[0064] The relative density of the powder compact is preferably 90% or more. By increasing the density of the powder compact, the magnetic properties of the powder compact are improved. The relative density of the powder compact is preferably 93% or more, more preferably 94% or more, and even more preferably 95% or more. The above relative density is a value obtained by dividing the actual density of the powder compact by the true density. The actual density is obtained by measuring the volume of the powder compact by the Archimedes method and dividing the mass of the powder compact by the measured volume. The true density can be obtained by using a measuring device such as a pycnometer.

[0065] ·yoke The yoke 5 is an annular member. In this example, the yoke 5 is formed from a single member. The yoke 5 may be formed by combining a plurality of divided pieces. For example, the annular yoke 5 may be produced by joining together sector-shaped divided pieces.

[0066] The yoke 5 is formed of a powder molded body, similar to the teeth 4. The composition of the powder molded body forming the yoke 5 may be the same as or different from the composition of the powder molded body forming the teeth 4. The relative density of the yoke 5 may be the same as or different from the relative density of the teeth 4. However, the relative density of the yoke 5 is preferably 90% or higher.

[0067] Teeth and yoke connection structure The teeth 4 and yoke 5 constituting the core 30 are fixed by tapping screws 6. The tapping screws 6 are attached from the surface of the yoke 5 opposite to the teeth 4 toward the teeth 4. The core 30, the teeth 4, and the yoke 5 are the connecting body 1, the first member 11, and the second member 12, respectively.

[0068] As shown in Figs. 4 and 5, the connecting body 1 of this example is provided with a pilot hole 7 that penetrates the second member 12 and reaches the first member 11. In other words, the pilot hole 7 is provided from the first member 11 to the second member 12. The pilot hole 7 is composed of a through hole provided in the second member 12 and a blind hole provided in the first member 11. The through hole and the blind hole are coaxial. In addition, the inner diameter of the through hole is the same as or larger than the inner diameter of the blind hole. This pilot hole 7 is provided in the first member 11 and the second member 12 in advance. The thread portion 65 (Fig. 5) of the tapping screw 6 bites into the inner peripheral surface of this pilot hole 7.

[0069] It is preferable that five or more peaks 65 are embedded in the pilot hole 7. Specifically, it is preferable that five or more peaks 65 are embedded in a portion of the pilot hole 7 that corresponds to the first member 11. By having five or more peaks 65 embedded in the pilot hole 7, the first member 11 and the second member 12 are firmly fixed to each other.

[0070] As shown in FIG. 5, the inner diameter h of the pilot hole 7 is 83% to 95% of the diameter d of the thread of the tapping screw 6, and is larger than the diameter d1 of the root of the tapping screw 6. The diameter d of the thread is the diameter of a portion corresponding to the apex 65t of the thread 65 of the tapping screw 6. The diameter d1 of the root is the diameter of a portion corresponding to the bottom of the root 66. If the inner diameter h of the pilot hole 7 is 83% or more of the diameter d of the thread of the tapping screw 6, the thread 65 of the tapping screw 6 prevents excessive stress from acting on the pilot hole 7. If the inner diameter h of the pilot hole 7 is 95% or less of the diameter d of the thread of the tapping screw 6, the thread 65 will be sufficiently embedded in the pilot hole 7. If the inner diameter h of the pilot hole 7 is larger than the diameter d1 of the root of the tapping screw 6, the shaft 60 of the tapping screw 6 will not push the pilot hole 7 outward in the radial direction. Therefore, defects such as cracks are unlikely to occur in the first member 11 and the second member 12 formed from the powder compact.

[0071] A preferable value of the inner diameter h of the pilot hole 7 is 84% ​​to 94% of the thread diameter d of the tapping screw 6. A more preferable value of the inner diameter h of the pilot hole 7 is 85% to 93% of the thread diameter d of the tapping screw 6.

[0072] The valley portion 66 of the tapping screw 6 does not contact the pilot hole 7 (see also the photograph of the actual product in FIG. 6). Therefore, in the connecting body 1 of this example, a spiral gap 8 is formed that is surrounded by the outer circumferential surface of the tapping screw 6 and the inner circumferential surface of the pilot hole 7. The outer circumferential surface of the tapping screw 6 specifically refers to the outer circumferential surface of the crest portion 65 and the outer circumferential surface of the valley portion 66.

[0073] In a cross section cut by a plane including the axis of the tapping screw 6 shown in FIG. 5, the area of ​​the gap 8 in the predetermined region 80 is preferably 45% or more and 65% or less. The predetermined region 80 is a region surrounded by a first straight line L1, a second straight line L2, a third straight line L3, and a fourth straight line L4 in the cross section. The first straight line L1 is a straight line connecting the apex 65t of one crest 65 adjacent to the apex 65t of the other crest 65 in the axial direction. The second straight line L2 is a straight line including a valley bottom, which is the bottom of the valley portion 66 of the tapping screw 6, and extending along the valley bottom. The third straight line L3 is a straight line extending from the apex 65t of one crest 65 in a direction perpendicular to the axis. The fourth straight line L4 is a straight line extending from the apex 65t of the other crest 65 in a direction perpendicular to the axis.

[0074] If the area of ​​the gap 8 in the specified region 80 is 45% or more and 65% or less, it can be said that the amount of penetration of the tapping screw 6 into the pilot hole 7 is appropriate. Therefore, it can be said that a connected body 1 in which the area of ​​the gap 8 in the specified region 80 is 45% or more and 65% or less is a connected body 1 in which the first member 11 and the second member 12 are firmly fixed by the tapping screw 6. It can also be said that the connected body 1 is one in which cracks and the like are less likely to occur in the first member 11 and the second member 12, which are made of powder compacts. A more preferable area ratio is 47% or more and 63% or less. An even more preferable area ratio is 49% or more and 61% or less.

[0075] As shown in FIG. 4, it is preferable that a gap is formed between the bottom 7b of the pilot hole 7 and the tip 6p of the tapping screw 6. The distance between the bottom 7b of the pilot hole 7 and the tip 6p of the tapping screw 6 is preferably 0.5 mm or more and 5 mm or less. If the distance is 0.5 mm or more, the tip 6p of the tapping screw 6 does not press the bottom 7b of the pilot hole 7. Therefore, damage to the first member 11 by the tip of the tapping screw 6 is suppressed. Furthermore, if the distance is 5 mm or less, the substantial portion of the first member 11 is sufficiently secured. Therefore, deterioration of the magnetic properties of the first member 11 is suppressed. It is more preferable that the distance is 1 mm or more and 4 mm or less.

[0076] The tapping screw 6 in this example is a B-0 type tapping screw 6. The B-0 type tapping screw 6 is mainly used to fix a resin material. In order to make it easier to screw the tapping screw 6 into the pilot hole 7, the angle of the crest on the tip side of the tapping screw 6 may be made smaller than the angle of the crest on the base side.

[0077] The tapping screw 6 includes a shaft portion 60 having a thread portion 65, and a head portion 61 provided at one end of the shaft portion 60. The head portion 61 in this example is a pan head, but is not particularly limited thereto. For example, the head portion 61 may be a countersunk head, a truss head, or a binding head. The tapping screw 6 in this example further includes a washer portion 62 integrated with the head portion 61. The washer portion 62 may be omitted.

[0078] The pitch P of the tapping screw 6 is preferably 25% or more and 43% or less of the nominal diameter. The pitch P is the distance between two axially adjacent crests 65. If the pitch P is 25% or more of the nominal diameter, excessive stress is unlikely to act on the pilot hole 7. Furthermore, if the pitch P is 43% or less of the nominal diameter, the crests 65 of the tapping screw 6 will firmly bite into the pilot hole 7. Therefore, the first member 11 and the second member 12 are firmly fixed by the tapping screw 6. The pitch P is more preferably 28% or more and 40% or less of the nominal diameter.

[0079] The tapping screw 6 may be a non-magnetic material or a magnetic material. Examples of the non-magnetic material include resin, titanium alloy, brass, aluminum alloy, magnesium alloy, and non-magnetic stainless steel. Examples of the resin include nylon (registered trademark), polycarbonate, and PEEK (polyetheretherketone). These non-magnetic materials are suitable as materials for the tapping screw 6 because of their excellent strength. If the tapping screw 6 is a non-magnetic material, the generation of eddy current in the tapping screw 6 is suppressed. Therefore, the core loss, which is the energy loss in the core 30, is reduced. In particular, stainless steel has excellent corrosion resistance, and therefore loosening of the tapping screw 6 due to corrosion can be suppressed.

[0080] Examples of the magnetic material constituting the tapping screw 6 include steel and ferromagnetic stainless steel. These magnetic materials have excellent strength and are therefore suitable as materials for the tapping screw 6. If the tapping screw 6 is a magnetic material, the tapping screw 6 functions as a part of the core 30. This prevents a decrease in torque of the rotating electric machine 100 (FIG. 1) caused by the use of the tapping screw 6. In particular, stainless steel has excellent corrosion resistance and can prevent the tapping screw 6 from loosening due to corrosion.

[0081] The inner peripheral surface of the pilot hole 7 provided in the first member 11 and the second member 12 preferably has a tapered shape with an inclination of 1° to 10° with respect to the axis. When the pilot hole 7 has a tapered shape, the inner diameter h of the pilot hole 7 must satisfy the provisions of the present disclosure at the point where the inner diameter h of the pilot hole 7 is smallest among the points where the thread portion 65 of the tapping screw 6 contacts the pilot hole 7. The pilot hole 7 having a predetermined tapered shape can be provided by molding. For example, the first member 11 and the second member 12 can be made using a mold equipped with a core for providing the pilot hole 7. In this case, if the pilot hole 7 has a tapered shape, the core can be easily removed from the first member 11 and the second member 12. When the pilot hole 7 is made in the first member 11 and the second member 12 by molding, there is no need to perform machining on the first member 11 and the second member 12. Therefore, cracks and the like are less likely to occur in the first member 11 and the second member 12.

[0082] In a cross section cut along a plane including the axis of the tapping screw 6 shown in Fig. 4, the thickness of the first member 11 and the thickness of the second member 12 from the inner peripheral surface of the pilot hole 7 in a direction perpendicular to the axis are preferably 2 mm or more. The direction perpendicular to the axis is the left-right direction on the paper in Fig. 4. In this configuration, the thickness of the first member 11 and the second member 12 on the radially outer side of the pilot hole 7 is sufficiently ensured. Therefore, when the first member 11 and the second member 12 are fixed together by the tapping screw 6, cracks are unlikely to occur in the first member 11 and the second member 12.

[0083] As shown in Fig. 5, a filler 8r may be disposed in the gap 8. The filler 8r is preferably filled in the pilot hole 7 before fixing with the tapping screw 6. By disposing the filler 8r in the pilot hole 7, cracks and the like are less likely to occur in the first member 11 and the second member 12 when the tapping screw 6 is attached to the pilot hole 7. This is because friction between the tapping screw 6 and the pilot hole 7 is reduced. In addition, by filling the gap 8 with the filler 8r, the strength of the first member 11 and the second member 12 is improved. As the filler 8r, for example, an epoxy adhesive can be used.

[0084] Effect of this embodiment In the above embodiment, the core 30 is the connector 1, the teeth 4 are the first member 11, and the yoke 5 is the second member 12. The core 30 in the above embodiment is produced by simply fixing the teeth 4 and the yoke 5 with the tapping screws 6. Fixing with the tapping screws 6 is easier than fixing by press-fitting or by adhesive. Therefore, the core 30 in embodiment 1 is excellent in productivity.

[0085] The stator 3 (FIG. 1) including the core 30 of the above embodiment has excellent productivity. This is because the core 30 included in the stator 3 has high productivity.

[0086] The rotary electric machine 100 including the stator 3 of the above embodiment has excellent productivity. This is because the productivity of the stator 3 included in the rotary electric machine 100 is high.

[0087] <Embodiment 2> In the second embodiment, a rotating electrical machine 100 in which a core 30 is fixed to a housing 9 by a tapping screw 6 will be described with reference to FIG.

[0088] The core 30 of the second embodiment is a powder compact in which the teeth 4 and the yoke 5 are integrated together. That is, in this example, the core 30 is the first member 11. This core 30 is fixed to the housing 9 by a tapping screw 6. That is, in this example, the housing 9 is the second member 12. The material of the housing 9 can be a non-magnetic material such as an aluminum alloy.

[0089] If the inner diameter of the pilot hole 7 is the same as that of the first embodiment, the core 30 of the powder compact is fixed to the housing 9 without cracks or breaks occurring in the core 30. In the configuration of this embodiment, the rotating electric machine 100 can be easily manufactured because the core 30 can be fixed to the housing 9 simply by the worker screwing the core 30 into the housing 9.

[0090] <Embodiment 3> In the third embodiment, a rotating electric machine 100 in which flange portions 45 are provided at the ends of the teeth 4 will be described with reference to FIG.

[0091] In this embodiment, the teeth 4 are provided at their ends opposite the yoke 5 with flanges 45 that protrude in a direction perpendicular to the protruding direction of the teeth 4. The flanges 45 prevent the coils 31 arranged on the teeth 4 from coming off the teeth 4. The flanges 45 also improve the performance of the axial gap type rotating electric machine 100.

[0092] In this example, the teeth 4 and the yoke 5 are integrated into a first member 11 of the powder compact. On the other hand, the flange 45 is a second member 12 separate from the teeth 4. The flange 45 may be a powder compact or a laminated steel plate.

[0093] If the inner diameter of the pilot hole 7 is the same as that of the first embodiment, even if the flange portion 45 is a powder compact, no cracks or breaks will occur in the flange portion 45. The configuration of this example makes it easy to form the flange portion 45. This is because the flange portion 45 is fixed to the teeth 4 by an operator simply screwing the flange portion 45 to the end of the teeth 4. This improves the productivity of the rotating electric machine 100. Furthermore, according to the configuration of this example, the gap between the teeth 4 and the flange portion 45 can be made smaller than in the conventional configuration in which fixing is performed with an adhesive, and deterioration of motor performance can be suppressed.

[0094] <Modification 3-1> As a modified example of the third embodiment, the configuration of the first embodiment is applied to the configuration of the third embodiment. That is, the teeth 4, the yoke 5, and the flange 45 are separately manufactured, and the teeth 4 and the yoke 5 are screwed together, and the teeth 4 and the flange 45 are screwed together. In the connection between the teeth 4 and the yoke 5, the teeth 4 are the first member 11, and the yoke 5 is the second member 12. In the connection between the teeth 4 and the flange 45, the teeth 4 are the first member 11, and the flange 45 is the second member 12.

[0095] <Modification 3-2> As a modified example of the third embodiment, the configuration of the second embodiment is applied to the configuration of the third embodiment. That is, the teeth 4 of the core 30 are screwed to the flange portion 45, and the core 30 is screwed to the housing 9. In the connection between the teeth 4 and the flange portion 45, the core 30 is the first member 11, and the flange portion 45 is the second member 12. In the connection between the core 30 and the housing 9, the core 30 is the first member 11, and the housing 9 is the second member 12.

[0096] <Embodiment 4> The tapping screw 6 used in the first to third embodiments may be a B-1 type tapping screw 6 shown in Fig. 9. The B-1 type tapping screw 6 has a groove 69 at its tip. In the B-1 type tapping screw 6, the edge of the groove 69 functions as a cutting edge.

[0097] <Test Example> In the test examples, cores of Samples No. 1 to No. 5 shown below were fabricated. Then, the presence or absence of cracks during fabrication was checked for each core. In addition, the core loss in rotating electrical machines using the cores of Samples No. 1 to No. 5 was checked.

[0098] <Sample information> Sample No.1 The core of sample No. 1 was obtained by fixing separately manufactured teeth and a yoke with an adhesive. The relative density of both the teeth and the yoke was 95%.

[0099] Sample No. 2 The core of sample No. 2 was obtained by fixing the teeth and the yoke with a tapping screw. The tapping screw was Enplatite (product name) manufactured by Nitto Seiko Co., Ltd. The dimensions and relative density of the teeth and the yoke were the same as those of the first embodiment. The tapping screw was B-0 type, with a crest diameter of 3 mm and a root diameter of 2.3 mm. Meanwhile, the inner diameter of the pilot hole was 2.4 mm. The inner diameter of the pilot hole 7 was the diameter before the tapping screw was attached. The inner diameter of the pilot hole / the crest diameter of the tapping screw was 0.8. That is, the inner diameter of the pilot hole was 80% of the crest diameter of the tapping screw. The tapping screw was attached with an electric screwdriver. The rotation speed of the tapping screw was 300 rpm, and the force for turning the tapping screw was 49 N·m.

[0100] Sample No.3 The core of sample No. 3 was the same as the core of sample No. 2, except that the inner diameter of the pilot hole was 2.5 mm. The inner diameter of the pilot hole in sample No. 3 was 83% of the diameter of the thread of the tapping screw.

[0101] Sample No.4 The core of sample No. 4 is the same as the core of sample No. 2, except that the inner diameter of the pilot hole is 2.8 mm. The inner diameter of the pilot hole in sample No. 4 was 93% of the diameter of the thread of the tapping screw 6.

[0102] Sample No. 5 The core of sample No. 5 is the same as the core of sample No. 2, except that the inner diameter of the pilot hole is 2.9 mm. The inner diameter of the pilot hole in sample No. 5 was 97% of the diameter of the thread of the tapping screw 6.

[0103] Sample No.6 The core of sample No. 6 is the same as the core of sample No. 2, except that the tapping screw 6 had a crest diameter of 4 mm, a root diameter of 3.0 mm, and an inner diameter of the pilot hole of 3.6 mm. The inner diameter of the pilot hole in this sample No. 5 was 90% of the crest diameter of the tapping screw.

[0104] <Test Results> The presence or absence of cracks in each sample and the core loss (W / kg) were checked. The presence or absence of cracks was checked visually. The core loss was measured under the conditions of 1.0T / 1kHz. The results for each sample are shown in Table 1 below. In Table 1, "inner diameter of pilot hole / diameter of thread of tapping screw" is shown as "pilot hole diameter / diameter of thread". "Presence or absence of cracks" in Table 1 indicates whether or not hairline cracks had occurred in either the yoke or teeth.

[0105] For each sample, the starting torque (N·m), breaking torque (N·m), appropriate tightening torque range (N·m), loosening rate (%), and screw extraction force (kN) were measured. The starting torque is the torque at which a thread begins to form in the pilot hole. The breaking torque is the torque at which at least one of the male thread of the tapping screw or the female thread formed in the pilot hole breaks. The starting torque and breaking torque were measured using a commercially available torque measuring device. The larger the size of the tapping screw, the greater the starting torque and breaking torque.

[0106] The appropriate tightening torque range is from 1.5 x (starting torque) to 0.65 x (breaking torque). The wider this range is, the easier it is to tighten the tapping screw and fix it to the target.

[0107] The loosening rate is expressed as (T / 1) x 100, where T is the torque required to loosen the tapping screw by rotating it in the reverse direction after it has been tightened with a force of 1 N m. If the loosening rate is 50% or more, it can be determined that the tapping screw is biting into the pilot hole.

[0108] The screw extraction force was examined using a measurement sample prepared separately from the core. The measurement sample was a powder compact made of the same material as the core and having the same relative density. The measurement sample had a through hole formed as a pilot hole. After a tapping screw was fastened into the pilot hole of the measurement sample, the maximum load required to push the tip of the shank of the tapping screw, i.e., the end opposite the head, to push the tapping screw out of the pilot hole was the screw extraction force. The greater the screw extraction force, the more difficult it is for the tapping screw to come out of the pilot hole.

[0109] [Table 1]

[0110] As shown in Table 1, the core loss of sample No. 1 was 25 W / kg. Moreover, no cracks occurred in sample No. 1, in which the teeth and yoke were connected with an adhesive.

[0111] In the core of sample No. 2, where the inner diameter of the pilot hole was less than 83% of the diameter of the thread of the tapping screw, cracks occurred in the teeth and yoke. On the other hand, in the cores of sample No. 3 to No. 6, where the inner diameter of the pilot hole was 83% or more of the diameter of the thread of the tapping screw, no cracks occurred in the teeth and yoke. Therefore, it was found that in order to fix the teeth and yoke made of powder compacts with a tapping screw, the inner diameter of the pilot hole needs to be 83% or more of the diameter of the thread of the tapping screw.

[0112] The core loss of sample No. 2 was larger than those of samples No. 3 and No. 6. The larger core loss of sample No. 2 is presumably due to the occurrence of cracks in the core.

[0113] In the core of sample No. 5, in which the inner diameter of the pilot hole was more than 95% of the diameter of the thread of the tapping screw, the appropriate tightening torque range of the tapping screw was narrow, and the tapping screw was difficult to tighten. In addition, in the core of sample No. 5, the screw extraction force was small, and the tapping screw was easily removed from the pilot hole. On the other hand, in the cores of samples No. 3, 4, and 6, in which the inner diameter of the pilot hole was 95% or less of the diameter of the thread of the tapping screw, the appropriate tightening torque range of the tapping screw was wide, and the tapping screw was easily tightened. In addition, in the cores of samples No. 3, 4, and 6, the screw extraction force was large, and the tapping screw was difficult to remove from the pilot hole. [Explanation of symbols]

[0114] 100 Rotating Electric Machine 1 Concatenation 11 first member, 12 second member 2 Rotors 20 shaft, 21 retaining plate, 22 magnet 3 Stator 30 Core, 31 Coil, 33 Bearing 4 Teeth 5. York 6 Tapping screws 60 shaft portion, 61 head portion, 62 washer portion, 65 crest portion, 65t apex 66 valley, 69 groove 7 Pilot hole 8. Gap 8r filler 80 Predetermined area L1 first straight line, L2 second straight line, L3 third straight line, L4 fourth straight line 9. Housing

Claims

1. A first member constituting at least a part of a core of a rotating electric machine; A second member separate from the first member; a tapping screw that penetrates the second member to reach the first member and connects the first member and the second member; the first member is the core, the second member is a housing that accommodates the core, The first member is formed of a powder compact of soft magnetic powder, The first member has a relative density of 90% or more, The tapping screw is a magnetic material, Of the first member and the second member, at least the first member has a pilot hole into which a thread portion of the tapping screw bites, The inner diameter of the pilot hole is 83% or more and 95% or less of the diameter of the crest of the tapping screw and is larger than the diameter of the root of the tapping screw, a spiral gap surrounded by an outer circumferential surface of the tapping screw and an inner circumferential surface of the pilot hole; In a cross section cut by a plane including an axis of the tapping screw, the area of ​​the gap occupies 45% or more and 65% or less of a predetermined region, The predetermined area is a first straight line connecting an apex of one ridge portion and an apex of another ridge portion adjacent to each other in the direction of the axis; A second straight line including a root of the tapping screw and extending along the root; a third straight line extending from the apex of the one of the peaks in a direction perpendicular to the axis; a fourth straight line extending from the apex of the other peak portion in a direction perpendicular to the axis, The distance between the bottom of the pilot hole and the tip of the tapping screw is 0.5 mm or more and 5 mm or less. Connector.

2. A first member constituting at least a part of a core of a rotating electric machine; A second member separate from the first member; a tapping screw that penetrates the second member to reach the first member and connects the first member and the second member; The first member is a tooth used in the core, The second member is a yoke used in the core or a flange portion provided on an end of the tooth, The first member and the second member are both formed of a powder compact of soft magnetic powder, The first member and the second member each have a relative density of 90% or more; The tapping screw is a magnetic material, Of the first member and the second member, at least the first member has a pilot hole into which a thread portion of the tapping screw bites, The pilot hole is provided from the first member to the second member, The inner diameter of the pilot hole is 83% or more and 95% or less of the diameter of the crest of the tapping screw and is larger than the diameter of the root of the tapping screw, a spiral gap surrounded by an outer circumferential surface of the tapping screw and an inner circumferential surface of the pilot hole; In a cross section cut by a plane including an axis of the tapping screw, the area of ​​the gap occupies 45% or more and 65% or less of a predetermined region, The predetermined area is a first straight line connecting an apex of one ridge portion and an apex of another ridge portion adjacent to each other in the direction of the axis; A second straight line including a root of the tapping screw and extending along the root; a third straight line extending from the apex of the one of the peaks in a direction perpendicular to the axis; a fourth straight line extending from the apex of the other peak portion in a direction perpendicular to the axis, The distance between the bottom of the pilot hole and the tip of the tapping screw is 0.5 mm or more and 5 mm or less. Connector.

3. The soft magnetic powder is an aggregate of soft magnetic particles having an insulating coating on the surface, 3. The coupled body according to claim 1, wherein the soft magnetic particles are at least one selected from the group consisting of pure iron, Fe-Si-Al alloys, Fe-Si alloys, Fe-Al alloys, and Fe-Ni alloys.

4. The connector according to any one of claims 1 to 3, wherein the tapping screw is a B-0 type or a B-1 type.

5. 5. The connector according to claim 1, wherein an angle of a thread portion on a tip side of the tapping screw is smaller than an angle of a thread portion on a base side of the tapping screw.

6. The connector according to claim 1 , wherein the magnetic material is steel or magnetic stainless steel.

7. The connector according to claim 1 , wherein five or more of the ridges are inserted into the pilot hole of the first member.

8. 8. The connector according to claim 1, wherein an inner peripheral surface of the pilot hole has a tapered shape having an inclination of 1° to 10° with respect to an axis of the pilot hole.

9. 9. A connector as described in any one of claims 1 to 8, wherein in a cross section cut on a plane including the axis of the tapping screw, the thickness of the first member and the thickness of the second member from the inner surface of the pilot hole in a direction perpendicular to the axis of the pilot hole are 2 mm or more.

10. The connector of claim 1 , further comprising a filler material disposed in the helical gap.

11. The connector according to any one of claims 1 to 10, wherein the head of the tapping screw is a countersunk type, a truss type, or a bind type.

12. An axial gap type rotating electric machine in which a rotor and a stator are arranged in an axial direction of a rotation shaft of the rotor, The connector according to any one of claims 1 to 11, Rotating electric motor.

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