JP5862156B2 - Field pole magnet body manufacturing apparatus and method - Google Patents

Description

  The present invention relates to an apparatus for manufacturing a field pole magnet body disposed on a rotor core of a permanent magnet embedded rotary electric machine and a method for manufacturing the same.

  Conventionally, as a field pole magnet body disposed in a rotor core of a permanent magnet embedded rotary electric machine, a rectangular magnet body (hereinafter simply referred to as a magnet body) in plan view is divided into a plurality of magnet pieces. A field pole magnet body formed by adhering magnet pieces together is known. In this way, the field pole magnet body is formed of a plurality of magnet pieces, and the volume of each magnet piece is reduced to reduce eddy currents generated by fluctuations in the acting magnetic field. Thereby, the heat generation of the field pole magnet body due to the eddy current is suppressed, and irreversible thermal demagnetization is prevented (see Patent Document 1).

  In Patent Literature 1, an upper die and a lower die each having a notch extending in the magnet width direction, which is a guide for cleaving, are provided in advance in a magnet body having substantially the same size and shape as the rotor slot, and having contact portions that contact the magnet body. The magnet body is cleaved and divided by sandwiching the magnet body.

JP 2009-148201 A

  By the way, when the magnet body is cleaved into magnet pieces, the accuracy of the cleaved surface may deteriorate due to abnormal cracks in which the cleaved surface of the magnet piece deviates from the planned cutting surface or becomes bifurcated. It is presumed that this occurs when the upper mold contact part (the part contacting the magnet body) hits the magnet body at the time of cleaving. As described above, as a factor that the upper mold contact portion comes into contact with the magnet body, foreign matter such as fine powder generated at the time of cleaving is caught between the lower mold contact section and the magnet body. When the body is cleaved, the magnet body is supported in a floating state by contacting the lower mold contact portion with a foreign object at one point away from the center in the width direction of the magnet body.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a field pole magnet body manufacturing apparatus and a manufacturing method thereof suitable for improving the accuracy of the fractured section.

The present invention relates to an apparatus for manufacturing a magnetic body for field poles that cleaves a magnet body by bringing the abutment portion of the upper mold into contact with and pressing the magnet body placed in contact with the abutment portion of the lower mold. Is targeted. And in the present invention, the magnet body is made of a material having a higher Young's modulus, and both sides of the magnet body are compressed from the upper and lower surfaces of the magnet body across the planned cutting surface of the magnet body, and compressive force is applied to the both side areas. A compressive force applying means for applying is provided, and the magnet body is cleaved in a state in which the compressive force is applied to both side regions of the planned cutting surface of the magnet body by the compressive force applying means.

Therefore, in the present invention, by providing a compressive force application region to which a compressive force is applied from the upper and lower surfaces of the magnet body on both sides of the planned splitting surface, the compressive force applied region of the crack generated by the cleaving operation is provided. Intrusion can be suppressed. For this reason, the shift | offset | difference from the fracture | rupture plan surface of a crack can be prevented, and a crack cross-section precision can be improved.

The schematic block diagram which shows the structure of the principal part of the permanent magnet type electric motor to which the magnet body manufactured with the manufacturing apparatus of the magnetic body for field poles in this embodiment is applied. The block diagram which shows the structure of a magnet body. The schematic block diagram of the manufacturing apparatus of the magnetic body for field poles in 1st Example of this embodiment. The principal part enlarged view of the manufacturing apparatus of the magnetic body for field poles shown in FIG. Sectional drawing of the principal part of the magnet cleaving apparatus by the AA line of FIG. The top view and side view (B) explaining the acting force which acts on a magnet body at the time of cleaving. The schematic block diagram which shows the other example of the manufacturing apparatus of the magnetic body for field poles. Explanatory drawing explaining the abnormal cracking state at the time of the cleaving of a magnet body.

  First, the field pole magnet body disposed in the rotor core of the rotating electrical machine of the present invention will be described.

  In FIG. 1, a permanent magnet embedded type rotary electric machine A (hereinafter, simply referred to as “rotary electric machine”) is arranged in a ring-shaped stator 10 that constitutes a part of a casing (not shown), and coaxially arranged with the stator 10. And a cylindrical rotor 20.

  The stator 10 includes a stator core 11 and a plurality of coils 12. The plurality of coils 12 are accommodated in slots 13 formed at equal angular intervals on the same circumference around the axis O in the stator core 11. The

  The rotor 20 includes a rotor core 21, a rotating shaft 23 that rotates integrally with the rotor core 21, and a plurality of field pole magnet bodies 80. The plurality of field pole magnet bodies 80 are centered on the axis O. The slots 22 are formed at equal angular intervals on the same circumference.

  As shown in FIG. 2, the field pole magnet body 80 accommodated in the slot 22 of the rotor 20 has a plurality of magnet pieces 31 obtained by cleaving and dividing the magnet body 30, and the divided sections are bonded to each other with a resin 32. It is configured as an aggregate of magnet pieces 31 aligned in a row. As the resin 32 used, for example, a resin having a heat resistance of about 200 ° C. is used, and the adjacent magnet pieces 31 are electrically insulated from each other. For this reason, the eddy current generated by the fluctuation of the acting magnetic field is reduced by staying in the individual magnet pieces 31, the heat generation of the field pole magnet body 80 due to the eddy current is suppressed, and irreversible thermal demagnetization is prevented. To do.

  In order to cleave the magnet body 30 into the plurality of magnet pieces 31, it is effective to form a notch groove 33 in advance in a portion (scheduled to be cleaved surface) of the magnet body 30. Below, although the magnet body 30 in which the notch groove 33 is formed will be described, the notch groove 33 is not indispensable. If the notch groove 33 is not provided, the magnet body 30 can be cleaved. The notch groove 33 may not be provided. As the notch groove 33 to be provided is deeper from the surface and the sharpness of the tip of the notch groove 33 is sharper, the flatness of the cut section when cleaved as the magnet piece 31 is improved. In the following, it is assumed that the notch grooves 33 are provided at predetermined intervals in the longitudinal direction of the magnet body 30.

  As the method of forming the notch groove 33, a method of forming the magnet body 30 by a groove forming protrusion provided on the mold of the magnet body 30, a method of machining by a dicer or the like, a method of laser beam irradiation Etc.

  Hereinafter, the manufacturing apparatus and the manufacturing method of the field pole magnet body 80 used in the permanent magnet embedded type rotary electric machine A of the present invention will be described based on one embodiment.

  FIG. 3 is a schematic configuration diagram illustrating a magnet body cleaving apparatus that is a field pole magnet body manufacturing apparatus disposed in a rotor core of a rotating electrical machine according to an embodiment to which the present invention is applied. 4 is an enlarged view of the main part of the magnet cleaving apparatus, and FIG. 5 is a cross-sectional view of the main part of the magnet cleaving apparatus taken along line AA in FIG.

  The magnet cleaving device 40 for the magnet body 30 cleaves the magnet body 30 into a plurality of magnet pieces 31. The magnet cleaving device 40 is a mold including a lower mold 41 that supports and guides the magnet body 30 and an upper mold 45 that cleaves the blade body 46 by pressing the blade 46 against the positioned magnet body 30. Further, the magnet cleaving device 40 is arranged on both sides of the planned cleaving surface of the magnet body 30 and the positioning device 44 for sequentially moving the magnet body 30 supported by the lower mold 41 and sequentially positioning the planned cleaving surface at the cleaving position. And a pair of clamps 50 that apply compressive stress to the magnet body 30.

  The lower mold 41 that supports and guides the magnet body 30 includes a plurality of protrusion portions 42 (contact portions) extending on the upper surface corresponding to the extending direction of the cutout grooves 33 of the magnet body 30. On the upper surface of 42, the magnet body 30 is abutted and supported from below. The lower die 41 includes a through hole 43 that opens downward at a position corresponding to the blade 46 of the upper die 45, and a pair of protrusions 42 serving as contact portions with the magnet body 30 before and after the through hole 43. Is arranged.

  The upper die 45 includes a blade 46 extending corresponding to the extending direction of the cutout groove 33 of the magnet body 30 as a contact portion to the magnet body 30 for cleaving the positioned magnet body 30, and And a magnet jump prevention clamp 47 that suppresses the magnet body 30 from jumping up. The blade 46 is lowered by the upper die 45 to be pushed down while bringing the cutting edge into contact with the cutting position of the magnet body 30, and between the pair of protrusions 42 before and after the through hole 43 of the lower die 41. The magnet body 30 is cleaved by bending by three-point bending. The blade 46 is provided with a sharp cutting edge toward the magnet body 30 arranged in the width direction of the magnet body 30.

  The magnet jump-up prevention clamp 47 is formed by a leaf spring whose base is fixed to the upper die 45, and the magnet body 30 is pressed against the lower die 41 by its spring action to break the magnet body 30 (particularly the magnet on the tip side). It suppresses that the piece 31) jumps up.

  The positioning device 44 includes a pusher 44A that contacts the rear end of the magnet body 30 in the feeding direction and presses the magnet body 30, a holder 44B that contacts the front end of the magnet body 30 in the feeding direction and holds the magnet body 30; Consists of. The pusher 44 </ b> A includes a servo motor that pushes out the magnet body 30, and every time the cleaving operation is performed, the pusher 44 </ b> A is one pitch (adjacent notch grooves 33) of a predetermined length set by the notch groove 33. By repeating the pushing operation by the distance of (3), the planned cutting surface of the magnet body 30 is sequentially positioned at the cutting position.

  Each time the holder 44B is pushed out by one pitch by the pusher 44A, the holder 44B comes into contact with the front end of the magnet body 30 and applies a braking force to the magnet body 30, so that the moving amount of the magnet body 30 pushed out by the pusher 44A is exceeded. And the positioning accuracy of the magnet body 30 is improved. For this reason, when the magnet body 30 is cleaved, the holder 44B releases the contact with the front end of the magnet body 30 and allows the movement of the front end side magnet piece 31 cleaved from the magnet body 30.

  4 and 5, the pair of clamps 50 includes a lower clamp piece 51 that contacts the lower surface of the magnet body 30, an upper clamp piece 52 that contacts the upper surface of the magnet body 30, and upper and lower clamp pieces 51 and 52. And an actuator 53 that urges the magnet body 30 in the contact direction / removal direction. The upper and lower clamp pieces 51 and 52 are formed of cast iron or steel material having a higher Young's modulus than the magnet body 30. The Young's modulus of the magnet body 30 is, for example, about 160 to 170 GPa, and the Young's modulus of the upper and lower clamp pieces 51 and 52 formed of cast iron or steel is, for example, about 190 to 210 GPa.

  The lower clamp piece 51 is formed of a rod-like member extending in the lateral direction (width direction of the magnet 30), and is attached to the lower mold 41 via a pair of elastic bodies 54, for example, springs or rubber, disposed below both ends thereof. At the initial position where the external force is not supported, the upper surface is brought into contact with the lower surface of the magnet body 30. The lower clamp piece 51 is supported by the elastic body 54 and can move downward from the initial position in accordance with the pressing force from above. When the pressing force is released, the lower clamp piece 51 returns to the initial position. Further, the lower clamp piece 51 is supported by a pair of elastic bodies 54 at the lower ends of both ends thereof, and can swing in the longitudinal direction of the magnet body 30 (in the direction of arrow B in FIG. 4) with the both support portions as the center. is there.

  The upper clamp piece 52 is connected to both ends of the upper horizontal member 52A formed of a bar-shaped member extending in the horizontal direction (the width direction of the magnet 30) that can come into contact with the upper surface of the magnet body 30 and the magnet body 30. The vertical member 52B extends along the side surface and extends downward across the lower clamp piece 51, and the lower horizontal member 52C connecting the lower ends of the vertical member 52B. Since the elastic body 55 is disposed at the portion where the vertical member 52B straddles the lower clamp piece 51, the entire upper clamp piece 52 is elastically supported by the lower clamp piece 51, and the lower surface of the upper horizontal member 52A is a magnet. It is positioned at an initial position away from the upper surface of the body 30.

  The actuator 53 includes a plurality of cylinders fixed to the lower clamp piece 51, and a rod that expands and contracts from the cylinder is configured to press the lower lateral member 52C of the upper clamp piece 52 downward when extended. The actuator 53 is configured by a hydraulic cylinder or a pneumatic cylinder. When the actuator 53 is not operated, the upper clamp piece 52 is lifted by the elastic body 55, and the upper lateral member 52 </ b> A is in an initial position separated from the upper surface of the magnet body 30. Further, when the actuator 53 is operated, the upper clamp piece 52 is pressed downward against the elastic body 55 to be lowered, and the upper lateral member 52A is lowered from the initial position to contact the upper surface of the magnet body 30. Press down. As a result, the magnet body 30 is sandwiched and clamped between the upper lateral member 52A and the upper surface of the lower clamp piece 51.

  In the magnet body cleaving device 40 having the above configuration, the magnet body 30 is placed on the protrusion 42 of the lower mold 41, and the first cleaving schedule of the magnet body 30 is scheduled by the pusher 44A and the holder 44B of the positioning device 44. The surface is positioned between the pair of protrusions 42 of the lower mold 41 and the blade 46 of the upper mold 45. Next, the contact of the holder 44B with the magnet body 30 is released.

  The positioned magnet body 30 is disposed so as to penetrate between the upper surface of the lower clamp piece 51 and the lower surface of the upper lateral member 52 </ b> A of the upper clamp piece 52 in the pair of clamps 50. That is, it arrange | positions so that a pair of clamp 50 may exist in the both sides on both sides of the planned cutting surface formed with the notch groove 33. FIG. The upper surface of the lower clamp piece 51 is in contact with the lower surface of the magnet body 30, and the lower surface of the upper horizontal member 52 </ b> A in the upper clamp piece 52 faces the upper surface of the magnet body 30 with a gap.

  Next, the actuator 53 of the pair of clamps 50 is actuated, and the upper clamp piece 52 is pushed downward against the elastic body 55 to be lowered, and the upper horizontal member 52A is lowered from the initial position to cause the upper surface of the magnet body 30 to move upward. And press down. By pressing the upper horizontal member 52A against the magnet body 30, the upper surface of the lower clamp piece 51 and the upper horizontal member 52A of the upper clamp piece 52 are clamped by clamping the magnet body 30 from the upper and lower surfaces, thereby applying compressive stress.

  The magnet body 30 is compressed from the upper and lower surfaces by the clamp 50, and as shown in FIG. 6, in the region (hatched region in the drawing) in contact with the clamp 50, the thickness direction (Z direction) is generated by the compressive stress generated. And expands in the surface direction (X, Y direction). However, the Young's modulus E2 of the magnet body 30 is about 160 to 170 GPa, and the Young's modulus E1 of the clamp 50 formed of cast iron or steel is about 190 to 210 GPa. That is, Young's modulus E1 of the clamp 50> Young's modulus E2 of the magnet body 30. Due to the difference in Young's modulus between the materials constituting the magnet body 30 and the clamp 50, the clamp 50 is less likely to expand in the plane direction than the magnet body 30. For this reason, frictional force is generated on the contact surfaces of both due to the difference between the amount of expansion in the surface direction of the magnet body 30 and the amount of expansion in the surface direction of the clamp 50, and in the hatched region of the magnet body 30, the surface direction (X, The compression stress is applied in the (Y direction).

  Next, the upper die 45 is lowered, and the magnet jumping prevention clamp 47 provided on the upper die 45 comes into contact with the upper surface of the magnet body 30 to elastically press the magnet body 30 against the protrusion 42 of the lower die 41. Then, the magnet body 30 is held so as not to move.

  With further lowering of the upper die 45, the tip (lower end) of the blade 46 comes into contact with the cleaving position of the magnet body 30, and three points are formed between the pair of protrusions 42 before and after the through hole 43 of the lower die 41. The magnet body 30 is cut by being pushed down by bending. At the same time, the magnet body 30 is prevented from jumping up by the magnet jump-up prevention clamp 47. When the magnet body 30 is cleaved into the magnet body 30 and the magnet piece 31 by the blade 46 along the planned cutting surface, the magnet body 30 is temporarily inclined in a V shape in the lower mold 41. The left and right clamps 50 are integrally rotated with the magnet body 30 and the magnet piece 31 in a “C” shape, and this rotation is allowed by bending the elastic body 54 with respect to the lower mold 41.

  The inclined state of the magnet body 30 and the magnet piece 31 in the V shape is caused by the pressing force by the magnet jump-up prevention clamp 47 when the pressing force disappears when the blade 46 rises upon completion of cleaving. Return to the horizontal state. When the elastic body 54 supporting the clamp 50 with respect to the lower mold 41 returns to the bending state, the clamps 50 are rotated back to the parallel state from the “C” shape, and the magnet body 30 and the magnet piece 31 are rotated. Helps return to level.

  By the way, the crushed powder generated when the magnet body 30 is cleaved adheres to and accumulates on the upper surface of the protrusion 42 of the lower mold 41, so that it is caught between the magnet body 30 and the protrusion of the lower mold 41. The magnet body 30 may be supported in a state where it floats from the strip 42. In this way, the crushed powder is caught between the protrusion 42 of the lower mold 41 and the magnet body 30, and the magnet body is lifted from the protrusion 42 of the lower mold 41 as shown in FIG. When 30 is supported, an abnormal crack occurs when the magnet body 30 is cleaved due to foreign matter as crushed powder. In other words, in addition to the tension 1 in the longitudinal direction of the magnet body 30 that is legitimately generated at the time of cleaving, an abnormal tension 2 is also generated in the width direction of the magnet body 30 by the foreign object. This abnormal tension 2 causes the action of bending the magnet body 30 in the width direction, and as shown by the broken line in the figure, the magnet body 30 is also cleaved in the longitudinal direction, causing abnormal cracks in the magnet body 30. As a result, the surface accuracy of the split section is reduced.

  However, in the magnet body cleaving apparatus 40 of this embodiment, compressive stress is applied to the surface direction of the magnet body 30 by the pair of clamps 50 on both sides of the planned cutting surface of the magnet body 30. For this reason, even if the magnet body 30 is lifted and supported by the crushed powder from the protrusion 42 of the lower mold 41 and the abnormal tension 2 acts on the magnet body 30, it acts in the surface direction of the magnet body 30. The tension in the surface direction generated in the magnet body 30 at the time of cleaving can be canceled by the compressive stress. For this reason, it is possible to suppress the split cross section generated in the magnet body 30 at the time of cleaving from entering the region where the compressive stress is applied by the clamp 50, and the split cross section generated in the magnet body 30 is a range between the pair of clamps 50. Can be restricted within.

FIG. 6 is an explanatory diagram for explaining conditions for making the compressive stress in the surface direction generated by the clamping force by the clamp 50 larger than the maximum tensile stress generated when the magnet body 30 is cleaved. In FIG. 6, L: distance between fulcrums by the protrusion 42 of the lower die 41, Fa: cleaving load applied by the blade 46, W: width of the magnet body 30, h: thickness of the magnet body 30, Fb: by the clamp 50 Applied pressure, S: Pressurizing part length by the clamp 50. The bending moment M generated in the magnet body 30 at the time of cleaving, the sectional secondary moment Z of the magnet body 30, and the maximum tensile stress σa in the surface direction of the magnet body 30 are as follows:
M = Fa × L / 4
Z = W × ^h 2/6
σa = M / Z = (3 × Fa × L) / (2 × W × h ² )
It can be asked. Further, μ: When the friction coefficient between the clamp 50 and the magnet body 30 is used, the compressive stress σb in the surface direction generated in the magnet body 30 by the clamping force is
σb = (μ × Fb) / (W × S)
It can be asked. And the maximum tensile stress σa in the surface direction generated in the magnet body 30 and the compressive stress σb in the surface direction generated in the magnet body 30 by the clamping force are as follows:
σb> σa
In such a case, the tensile stress in the surface direction generated in the magnet body 30 at the time of cleaving can be canceled by the compressive stress in the surface direction of the magnet body 30. And it suppresses that the crack surface which generate | occur | produces in the magnet body 30 at the time of cleaving penetrate | invades in the area | region which has applied the compressive stress by the clamp 50, and the crack surface which generate | occur | produces in the magnet body 30 is in the range between a pair of clamps 50. Can be limited to. The compression force σb in the surface direction generated in the magnet body 30 by the clamping force> the pressing force (compression force) Fb by the clamp 50 that satisfies the maximum tensile stress σa in the surface direction generated in the magnet body 30 is as follows:
Fb> [(3 × S × L) / (2 × μ × h ² ))] × Fa
It can be asked.

here,
Pressure part length S by clamp 50: 1mm,
The distance L between the fulcrums by the protrusion 42 of the lower mold 41: 8 mm,
Friction coefficient μ between the clamp 50 and the magnet body 30: 0.1,
Thickness h of magnet body 30: 4 mm,
Cleaving load Fa applied by the blade 46: 1000N
Assuming that, the pressing force Fb by the clamp 50 is as follows:
Fb> {3 × S (0.001) × L (0.008)} × {Fa (1000)} / {2 × μ (0.1) × h (0.004) ² )} = 7500N
It can be asked.

  After cutting, the blade 46 is raised together with the upper mold 45. Since the magnet body 30 is pressed by the magnet jump prevention clamp 47 provided in the upper mold 45, the cleaved portion of the magnet body 30 also rises and returns. At the same time, the operation of the actuator 53 of the pair of clamps 50 is released, the upper clamp piece 52 is raised by the restoring force of the elastic body 55, and the upper lateral member 52A is raised to the initial position to contact the upper surface of the magnet body 30. Is released. When the upper horizontal member 52A is detached from the magnet body 30, the clamp 50 to the magnet body 30 is released. When the upper die 45 returns to the initial position, the magnet jumping prevention clamp 47 provided on the upper die 45 also releases the contact with the upper surface of the magnet body 30 and releases the holding of the magnet body 30. The magnet piece 31 at the tip that is cleaved from the magnet body 30 is conveyed by a conveying means (not shown) in the next process, is aligned in the cleaving order in the next process, and is bonded and integrated through an adhesive.

  Next, the magnet body 30 is pushed out by one pitch by the pusher 44A of the positioning device 44 and the front end of the magnet body 30 is contacted by the holder 44B to apply a braking force to the magnet body 30 to be next cleaved. The surface is positioned so as to face the blade 46 between the pair of protrusions 42.

  In the same manner as described above, the magnet body 30 is clamped by the pair of clamps 50, the magnet body 30 is cleaved by the lowering of the upper mold 45, and the operation of moving the magnet body 30 by one pitch by the positioning device 44 is repeated. It is.

  In addition, in the said embodiment, although what provided the pair of protrusion part 42 arranged in parallel which mounts the magnet body 30 in the lower mold | type 41 was demonstrated, it replaced with a pair of protrusion part 42, and between a pair of die | dyes. The magnet body 30 may be bridged and placed.

  Further, as the magnet body breaking device 40, the blade 46 of the upper mold 45 is lowered on the magnet body 30 placed on the lower mold 41 and brought into contact with the upper part of the section over which the magnet body 30 is bridged. The thing which cleaves the magnet body 30 by pressing is demonstrated. However, the magnet body cleaving device is not limited to this. For example, as shown in FIG. 7, a magnet that fixes the magnet body 30 in a protruding state from the lower mold 41 and projects the blade 46 of the upper mold 45. The magnet body 30 may be cleaved by contacting and pressing the tip of the body 30. In this case, as means for applying a compressive force to the magnet body 30, a fixing jig 47 for fixing the magnet body 30 portion mounted on the lower mold 41 to the lower mold 41, and a portion protruding from the lower mold 41 are provided. The clamp jig 50A clamps the side close to the base of the protruding piece. The clamp jig 50A on the side close to the base of the protruding piece is supported so as to be swingable together with the broken magnet piece 31 when the magnet body 30 is cleaved, and the cleaved magnet piece 31 is released by releasing the clamp. Therefore, it can be transported by a transport device or the like.

  In addition, the clamp 50 elastically supported by the lower mold 41 and operated by the actuator 53 has been described as means for applying a compressive force. However, although not illustrated, the clamp 50 is attached to the front and rear of each planned cutting surface of the magnet body 30 to be inserted. A plurality of clamping jigs each applying a compressive force to the magnet body 30 may be used.

  In the present embodiment, the following effects can be achieved.

  (A) The blade 46 of the upper mold 45 is pressed against the magnet body 30 that is provided on the lower mold 41 and is held by the abutting portion that holds the magnet body 30 in contact with the lower side of the magnet body 30. This is a manufacturing apparatus for the field pole magnet body 30 that cleaves the magnet body 30. As a compressive force applying means that is formed of a material having a higher Young's modulus than the magnet body 30 and applies a compressive force (pressing force) from the upper and lower surfaces of the magnet body 30 to both sides of the planned cutting surface of the magnet body 30. The magnet body 30 is cleaved in a state in which the compressive force is applied to both sides of the planned cutting surface of the magnet body 30 by the compression force applying means. In other words, by providing a region to which compressive force is applied on both sides of the planned cutting surface, the cracks generated by the cleaving operation are prevented from entering the compressive force applying region, and the deviation of the crack from the planned cutting surface is prevented. Can be prevented, and the accuracy of the fractured section can be improved.

  (A) By providing a notch groove 33 that is a starting point of the fracture crack in any part of the surface of the magnet body 30 to be cleaved, the notch groove 33 can easily generate a crack on the plane to be cleaved. Moreover, the cleaving load required at the time of cleaving can be kept low.

(C) a pair of abutting portions in the lower mold 41, by the pair of abutting portions are arranged on both sides respectively across the expected splitting surface of the magnet body 30, bridging floated its expected splitting surface The magnet body 30 is held in the state, and the blade 46 of the upper mold 45 is lowered toward the planned cutting surface of the held magnet body 30, and is brought into contact with the upper portion of the magnet body 30 and pressed to thereby press the magnet body 30. The upper and lower molds 41 and 45 are configured so as to cleave. And the clamp 50 as a compression force provision means is arrange | positioned on both sides across the planned cutting surface of the bridged magnet body 30 and applies a compression force from the upper and lower surfaces of the magnet body 30. That is, by cleaving the magnet body 30 with the lower die 41 and the upper die 45 by three-point bending, the compressive force applying means can be arranged symmetrically about the planned breaking surface of the magnet body 30 to be cleaved. The accuracy of the fractured section can be improved.

(D) The compression force Fb applied to the magnet body 30 by the clamp 50 which is the compression force applying means is S for the length of the pressurizing portion by the compression force applying means, and L is the distance between the fulcrums that are held in a state of being bridged to the lower die 41. When the thickness of the magnet body 30 is h, the friction coefficient between the compression force applying means and the magnet body 30 is μ, and the breaking load applied by the blade 46 is Fa,
Fb> [(3 × S × L) / (2 × μ × h ² )] × Fa
It was. As a result, the magnet body 30 is compressed on both sides of the planned cutting surface of the magnet body 30, and the spread in the surface direction of the magnet body 30 is limited by the frictional force of the contact surface with the compressive force applying means. Then, compressive stress is generated in the surface direction of the magnet body 30. This compressive stress in the plane direction cancels the tensile stress acting in the plane direction at the time of cleaving, suppresses the penetration of the cleaving crack generated in the magnet body into the compressive stress acting region, and improves the accuracy of the fractured surface.

A Permanent magnet type electric motor 10 Stator 20 Rotor 30 Magnet body 31 Magnet piece 33 Notch groove 41 Lower mold 42 Projection section 43 Through hole 44 Positioning device 44A Pusher 44B Holder 45 Upper mold 46 Blade 47 Bounce prevention clamp 50 Applying compression force Clamp as means 51 Lower clamp piece 52 Upper clamp piece 53 Actuator 54, 55 Elastic body 80 Field pole magnet body

Claims (6)

In the field pole magnet body manufacturing apparatus for cleaving the magnet body by pressing the upper body blade against the magnet body placed and held on the abutting portion provided in the lower mold,
Compression force applying means that is formed of a material having a higher Young's modulus than the magnet body , compresses both side regions from the upper and lower surfaces of the magnet body across the planned cutting surface of the magnet body, and applies compressive force to the both side regions. Provided,
An apparatus for manufacturing a magnetic body for field poles, wherein the magnet body is cleaved in a state where a compressive force is applied to both regions of the planned cutting surface of the magnet body by the compression force applying means.   2. The field pole magnet body manufacturing apparatus according to claim 1, wherein the magnet body is provided with a notch groove serving as a starting point of occurrence of a split crack in any part of a plane to be cut. The lower mold is provided with a pair of abutting portions spaced apart from each other , and the pair of abutting portions are arranged on both sides of the planned cutting surface of the magnet body so that the planned cutting surface is suspended. Hold the magnet body in the state, lower the upper mold blade toward the planned cutting surface of the held magnet body, and bring it into contact with the upper part of the magnet body so as to crush the magnet body so as to cleave the magnet body Make up mold,
The compressive force applying means compresses both side regions of the magnet body to be cleaved between the pair of contact portions from the upper and lower surfaces of the magnet body, and applies the compressive force to the both side regions. The field pole magnet body manufacturing apparatus according to claim 1 or 2. The compressive force Fb applied to the magnet body by the compressive force applying means is S for the length of the pressurizing portion by the compressive force applying means, L for the distance between fulcrums held in a state of being bridged to the lower mold, h for the thickness of the magnet body, When the friction coefficient between the compression force applying means and the magnet body is μ, and the breaking load applied by the blade is Fa,
Fb> [(3 × S × L) / (2 × μ × h2)] × Fa
The field pole magnet body manufacturing apparatus according to claim 3, wherein In the manufacturing method of the magnetic body for field poles, which breaks the magnet body by contacting and pressing the blade of the upper mold to the magnet body placed and held on the abutting portion provided in the lower mold,
By compressing force applying means formed of a material having a higher Young's modulus than the magnet body, both sides of the magnet body are compressed from the upper and lower surfaces of the magnet body across the planned cutting surface, and compressive force is applied to the both side areas. And
A method of manufacturing a field pole magnet body, wherein the magnet body is cleaved in a state where the compressive force is applied. A magnet body is placed on a pair of abutting portions provided on the lower mold so as to be spaced apart from each other so that the planned fracture surface is positioned between the pair of abutting portions and the planned fracture surface is floated. Manufacture of a magnetic body for field poles that is held in a handed state and cleaves the magnet body by lowering the upper die blade toward the cleaved surface of the magnet body and abutting against and pressing the upper part of the magnet body In the method
The compressive force applying means formed with a high Young's modulus than the magnet material, the both side area of the planned cutting surface of the magnet body between the pair of abutting portions is compressed from upper and lower surfaces of the magnet body Apply compressive force to both side areas ,
A method of manufacturing a field pole magnet body, wherein the magnet body is cleaved in a state where the compressive force is applied.

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