JP5811350B2 - Rotor manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a rotor of an electric motor that generates a rotational force on a rotating shaft, and a rotor.

  FIG. 11 shows the rotating shaft 103, the rotor 105, the stator 107, and the housing 109 of the electric motor 101. The rotor 105 includes a rotor core 113 in which a plurality of slits 111 are formed, and a magnet 115 that is injection-molded in the plurality of slits 111. FIG. 12A shows a process in which the material of the magnet 115 supplied from the injection molding machine using a plastic resin as a binder is filled into the plurality of slits 111 via the spool 117, the runner 119, and the gate 121. Illustration of an insert molding die into which the rotor core 113 is inserted is omitted. Reference numeral 104 denotes a shaft hole through which the rotating shaft 103 is inserted.

  The material of the magnet 115 hardens inside the slit 111 and becomes a permanent magnet by being magnetized. The magnet 115 immediately after the injection molding is in close contact with the rotor core 113. However, since the rotor core 113 and the magnet 115 have different thermal expansion coefficients, the close contact between the two becomes weaker as the cooling of the rotor 105 proceeds. Therefore, in order to restrict the magnet 115 from separating from the inside of the slit 111 in the axial direction indicated by the arrow S, a plate-like holding member 125 is provided on the end surface 123 of the rotor core 113 as shown in FIG. Is attached.

  However, it is troublesome to fix the holding member 125 to the rotor core 113 using screws or rivets. Further, the cost of machining a pilot hole such as a screw or a rivet in the rotor core 113 becomes excessive, and the pilot hole also causes a disturbance of the magnetic field generated by the magnet 115.

JP 2004-336831 A JP 2006-180677 A

  An object of the present invention is to provide a rotor manufacturing method and a rotor that can generate a magnetic field well and can simplify the manufacturing process.

The present invention provides a rotor core having a plurality of slits penetrating in the axial direction of the rotating shaft of the electric motor and having end surfaces in the axial direction, and magnets are injection-molded into the plurality of slits. A rotor manufacturing method for injection-molding a holding member that connects a plurality of injection-molded magnets to a plurality of slits, and an insert molding die is prepared in which a magnet using a plastic resin binder is supplied from an injection molding machine to a cavity A step of inserting the rotor core into the cavity, and a magnet supplied from the injection molding machine passes through a region of the cavity adjacent to the end surface of the rotor core, and a plurality of slits of the rotor core And a magnet supplied from the injection molding machine fills the region of the cavity as a material for molding the holding member. Ri Do and a step, wherein the plurality of slits are spaced in a radial direction of the rotary shaft to each other, the region of the cavities, leads to a magnet supplied from the injection molding machine in the radial direction It is characterized by that .

Further, the present invention provides a rotor core having a plurality of slits penetrating in the axial direction of the rotating shaft of the electric motor and having end surfaces in the axial direction, and magnets are injection-molded into the plurality of slits, and the end surfaces of the rotor core are formed. A method of manufacturing a rotor for injection molding a holding member that couples injection molded magnets to the plurality of slits, wherein an insert molding die in which a magnet using a plastic resin as a binder is supplied from an injection molding machine to a cavity A step of inserting the rotor core into the cavity, and a magnet supplied from the injection molding machine passes through a region of the cavity adjacent to the end face of the rotor core, and a plurality of the rotor cores are provided. The step of filling the slit of the magnet and the magnet supplied from the injection molding machine as the material for molding the holding member in the region of the cavity The plurality of slits are spaced apart from each other in the rotation direction of the rotary shaft, and the region of the cavity has a magnet supplied from the injection molding machine in the rotation direction. It is characterized by guiding .

Further, the present invention provides a rotor core having a plurality of slits penetrating in the axial direction of the rotating shaft of the electric motor and having end surfaces in the axial direction, and magnets are injection-molded into the plurality of slits, and the end surfaces of the rotor core are formed. A method of manufacturing a rotor for injection molding a holding member that couples injection molded magnets to the plurality of slits, wherein an insert molding die is supplied to a cavity with a plastic resin binder from an injection molding machine A step of inserting the rotor core into the cavity, and a magnet supplied from the injection molding machine passes through a region of the cavity adjacent to the end face of the rotor core, and a plurality of the rotor cores are provided. The step of filling the slit of the magnet and the magnet supplied from the injection molding machine as the material for molding the holding member in the region of the cavity The plurality of slits are spaced apart from each other in the rotational direction of the rotary shaft, and the region of the cavity has a magnet supplied from the injection molding machine as a rotation of the electric motor. It is characterized by being guided to flow in an annular shape around an axis.

Further, the present invention is the above-mentioned invention, wherein the insert molding die is formed with a gate in the cavity region, and the gate is formed of a plurality of slits arranged at intervals in the radial direction. Among them, a magnet supplied from the injection molding machine is introduced into the cavity toward the outermost slit in the radial direction.

  Further, according to the present invention, the insert molding die is formed with a gate in a region of the cavity, and the gate is the radial direction among a plurality of slits spaced from each other in the radial direction. A magnet supplied from the injection molding machine is introduced into the cavity toward the outer slit.

  The present invention also provides a rotor core having a plurality of slits extending in the axial direction of the rotating shaft of the electric motor and having end faces in the axial direction, a plurality of magnets respectively filled in the plurality of slits, and an end face of the rotor core And a holding member for connecting the plurality of magnets, wherein the plurality of slits are arranged at intervals in the radial direction of the rotating shaft, and the holding member holds the plurality of magnets. It extends in a transverse direction.

  Moreover, the present invention is characterized in that the holding member extends radially in the radial direction of the rotating shaft around the rotating shaft. Moreover, the present invention is characterized in that the holding member extends in a rotation direction of the rotation shaft. Further, the present invention is characterized in that the holding member extends in a ring shape around a rotation shaft of the electric motor.

  According to the method for manufacturing a rotor of the present invention, a plurality of slits of a rotor core are filled with a magnet material (hereinafter simply referred to as “magnet”) supplied from an injection molding machine as a plastic resin as a binder. The holding member can be formed by a magnet that fills a region adjacent to the end face of the rotor core. For this reason, since the magnet filled with the plurality of slits and the holding member can be integrally formed in the cavity of the insert molding die, it is possible to save the trouble of fixing the holding member to the rotor core. In addition, the rotor manufacturing method of the present invention and the rotor manufactured thereby do not require screws or rivets for attaching the holding member to the rotor core, and these pilot holes need not be processed into the rotor core. Therefore, the magnetic field generated by the rotor magnet can be kept good.

  Furthermore, according to the method for manufacturing a rotor of the present invention, the region adjacent to the end face of the rotor core of the cavity guides the magnet supplied from the injection molding machine in the radial direction of the rotary shaft, so that the radial distance from each other. A plurality of slits arranged with a gap between them can be filled uniformly with a magnet. The rotor of the present invention thus manufactured includes a holding member that extends radially in the radial direction around the rotation axis, and a magnet injection-molded in a plurality of slits can generate a desired magnetic field.

  Alternatively, the region adjacent to the end face of the rotor core of the cavity guides the magnet supplied from the injection molding machine in the axial direction of the rotating shaft, so that the magnets are arranged in a plurality of slits arranged at intervals in the rotating direction. Can be filled uniformly. The rotor of the present invention thus manufactured includes a holding member extending in the rotation direction of the rotating shaft or a holding member extending in an annular shape, and a magnet injection-molded into a plurality of slits can generate a desired magnetic field.

  Further, the air that contacts the end face of the rotor core flows along the holding member extending in the direction of rotation of the rotating shaft or in an annular shape when the rotor rotates. For this reason, according to the rotor of this invention, the efficiency of an electric motor can be improved by the part which can reduce the air resistance which a holding member receives.

  Further, according to the method for manufacturing a rotor of the present invention, the magnet is guided from the gate to the cavity toward the outermost slit in the radial direction among the plurality of slits arranged at radial intervals. Can do. Thereby, a plurality of slits having different sizes can be uniformly filled with magnets, and the above-described effect can be achieved.

Sectional drawing which shows the manufacturing process of the rotor which concerns on embodiment of this invention. Sectional drawing of the rotor which concerns on embodiment of this invention. (A) is a front view of the fixed mold of the insert mold used for manufacture of the rotor which concerns on Example 1 of this invention, (b) is a front view of the modification. Sectional drawing which shows the stationary metal mold | die of the insert molding metal mold | die used for manufacture of the rotor which concerns on embodiment of this invention. The perspective view which shows the principal part of the rotor which concerns on Example 1 of this invention. (A) is a front view of the fixed mold of the insert mold used for manufacture of the rotor which concerns on Example 2 of this invention, (b) is a front view of the modification. The perspective view which shows the principal part of the rotor which concerns on Example 2 of this invention. (A) is a front view of the fixed mold of the insert mold used for manufacture of the rotor which concerns on Example 3 of this invention, (b) is a front view of the modification. The front view of the further modification of the fixed metal mold | die of the insert mold used for manufacture of the rotor which concerns on Example 3 of this invention. The perspective view which shows the principal part of the rotor which concerns on Example 3 of this invention. Sectional drawing of an electric motor provided with the rotor of a prior art example. (A) is sectional drawing which shows one process of manufacturing the rotor of a prior art example, (b) is sectional drawing which shows another process.

  A method for manufacturing a rotor according to an embodiment of the present invention will be described. It is assumed that the same designations are used for the elements already described as conventional techniques regardless of whether or not they are illustrated. Further, the axial direction, radial direction, and rotational direction described below are based on the rotational axis of the electric motor.

  FIG. 1 shows a rotor core 7 having a plurality of slits 1 extending in the axial direction and having both end faces 3 and 5 in the axial direction, and an insert mold 11 in which the rotor core 7 is inserted into a cavity 9. ing. The rotor core 7 is obtained by laminating a plurality of core sheets made of a ferromagnetic material in the axial direction. The insert molding die 11 includes a fixed die 13 that is fixed to the injection molding machine, and a movable die 15 that is advanced and retracted in the axial direction with respect to the fixed die 13.

  The fixed mold 13 is formed in a shape in which the inner end of the cavity 9 is adjacent to one end face 3 of the rotor core 7 and is recessed with respect to the end face 3 of the rotor core 7. The movable mold 15 has a shape in which the inner end of the cavity 9 is adjacent to the other end surface 5 of the rotor core 7 and is recessed with respect to the end surface 5 of the rotor core 7.

  Hereinafter, unless otherwise specified, the drawings refer to FIGS. 1 and 2, and the insert molding die 11 with the rotor core 7 inserted into the cavity 9 will be described. Moreover, since the form of the cavity 9 of the movable mold 15 is the same as that of the fixed mold 13 except that the spool 19, the runner 21 and the gate 23 are formed in the fixed mold 13, the movable mold 15 Note that the cavity 9 of the fixed mold 13 is not shown.

  An injector of an injection molding machine is brought into contact with the spool 19 of the insert molding die 11. A magnet material (hereinafter, simply referred to as “magnet”) using a plastic resin supplied from the injector as a binder passes through the runner 21, the gate 23, and the region 17 of the fixed mold 13, and the rotor core 7. Each of the slits 1 is filled. In this process, the area 17 of the fixed mold 13 is filled with the magnet. Further, the magnet filled in the slit 1 reaches the other end face 5 of the rotor core 7, and the region 25 of the movable mold 15 is filled with this magnet.

  After the magnet is cured, the insert molding die 11 is opened, and the rotor 27 shown in FIG. The magnet that fills the regions 17 and 25 becomes the holding member 29. Subsequently, by magnetizing the magnet 31 of the rotor 27, a desired magnetic field can be generated around the rotor 27. In addition, the holding member 29 has a shape extending so as to intersect with the plurality of slits 1 and connects the magnets 31 filled in the plurality of slits 1 to each other, so that the magnets 31 are detached from the rotor core 7 in the axial direction. Can be restricted.

  Further, according to the rotor manufacturing method described above, the magnet 31 and the holding member 29 filled in all the slits 1 of the rotor core 7 can be integrally formed inside the cavity 9. The trouble of fixing 29 to the rotor core 7 can be saved. Moreover, the rotor manufacturing method of the present embodiment and the rotor 27 manufactured thereby do not require screws or rivets for attaching the holding member 29 to the rotor core 7. Therefore, the magnetic field generated by the magnet 31 of the rotor 27 can be kept good.

  FIG. 3A is a front view of the fixed mold 13 of the insert molding mold 11 shown in FIG. 4 as viewed in the direction of the arrow AA, and FIG. 3B shows a modification thereof. Yes. A plurality of slits 1 of the rotor core 7 and imaginary lines representing the shaft holes 104 are overlapped in the same figure.

  The slit 1 is an arc-shaped opening whose both ends 35 are directed outward in the radial direction, and penetrates the rotor core 7 in the axial direction. Four ranges 37 are assigned to the end faces 3 and 5 of the rotor core 7 at an equal angle of 90 ° around the rotation axis, and a plurality of slits 1 are opened in each range 37. These slits 1 are spaced from each other in the radial direction and spaced from each other in the rotational direction. The slits 1 have different overall lengths so that the volumes of the slits 1 disposed relatively radially inward among the plurality of slits 1 opened to the individual ranges 37 increase in order. The number of slits 1 opened to the individual ranges 37 is not limited to three.

  In this embodiment, the magnets supplied from the injection molding machine to the gate 23 shown in FIG. 4 are guided by the regions 17 and 25 in the radial direction. FIG. 3A shows four regions 17 arranged at an equal pitch of 90 ° in the rotation direction. The four regions 17 extend radially in the radial direction, and each region 17 may be a single groove or a groove branched into three as shown in FIG. Gates 23 are opened in the individual regions 17, and the individual gates 23 are arranged in the vicinity of the outermost slit 1 in the radial direction among the plurality of slits 1. This is because when the magnet supplied from the injection molding machine reaches the cavity 9, a plurality of slits 1 having different sizes are provided by first guiding the magnet toward the outermost slit 1 in the radial direction. This is because the magnet is uniformly filled.

  FIG. 5 shows a rotor 27 in which a holding member 29 is formed by the region 17 shown in FIG. 3A and a plurality of slits 1 are filled with magnets 31. The dimensions of each part of the rotor 27 and the ratio thereof are design items that are arbitrarily set, and the height of the holding member 29 protruding from the end face 3 of the rotor core 7 is exaggerated in the drawing. Reference numeral 39 indicates the core sheet.

  Since the term “range” described below is defined in the first embodiment, the illustration is omitted. In the present embodiment, the regions 17 and 25 guide the magnet in the rotation direction. FIG. 6A shows four regions 17 arranged at an equal pitch of 90 ° in the rotation direction. The region 17 is an arc-shaped groove extending in the rotation direction, and one end 41 of each of the ends of all the slits 1 formed in each range and all the ranges formed in the range adjacent thereto. It intersects with one end 43 of both ends of the slit 1. Gates 23 are opened in the individual regions 17, and the individual gates 23 are arranged between a plurality of slits formed in ranges adjacent to each other.

  The magnet supplied to the gate 23 from the injection molding machine further flows into the slit 1 from the region 17 of the cavity 9. In this process, the magnets go inward of the slits 1 from both ends 41 and 43 of the individual slits 1, thereby forming two flows in the directions of the arrows f and f ′. Since the flow of these magnets does not contact each other in the vicinity of both ends 41 and 43 of the slit 1, the generation of welds in the vicinity of both ends 41 and 43 of the slit 1 is suppressed, and the strength of the magnetic field is reduced by the welds. Can be prevented.

  As shown in FIG. 6B, the region 17 is formed in a range adjacent to the one end 41 of the innermost slit 1 in the radial direction among the plurality of slits 1 formed in each region 17. Further, it may extend to one end 43 of the innermost slit 1 in the radial direction among the plurality of slits 1. In this case, four auxiliary regions 45 that intersect all the slits 1 formed in the individual regions 17 and extend radially in the radial direction are formed in the cavity 9, and the individual regions 17 and the individual auxiliary regions 45 are formed. Each gate 23 is opened.

  FIG. 7 shows the rotor 27 in which the holding member 29 is formed by the region 17 shown in FIG. The air in contact with the end faces 3 and 5 of the rotor core 7 flows along the holding member 29 extending in the rotation direction when the rotor 27 rotates. For this reason, according to the rotor 27 of this invention, the efficiency of an electric motor can be improved by the part which can reduce the air resistance which the holding member 29 receives.

  In this embodiment, the regions 17 and 25 guide the magnet to flow in an annular shape. FIG. 8A shows a circular region 17 formed along the inner peripheral surface of the cavity 9. The region 17 intersects both ends 35 of all the slits 1, and the gate 23 is disposed between both ends 35 of each slit 1. This is because the magnet supplied to the gate 23 from the injection molding machine flows into the slit 1 from the region 17 to form two flows respectively directed from the both ends 35 of the individual slits 1 to the inside of the slit 1. This is because the above-mentioned effect is achieved.

  As shown in FIG. 8B, the radius of the region 17 may be large enough to intersect the innermost slit 1 in the radial direction among the plurality of slits 1 formed in each range. . Alternatively, as shown in FIG. 9, the region 17 may be a groove extending in a square shape. In this case, four auxiliary regions 45 extending in the radial direction so as to intersect all the slits 1 formed in the individual regions 17 are formed in the cavity 9. Each of the auxiliary regions 45 preferably extends so as to intersect a position that bisects the both ends 35 of the slit 1. The individual gates 23 are preferably opened in the vicinity of the auxiliary region 45 in the region 17.

  FIG. 10 shows the rotor 27 in which the holding member 29 is formed by the region 17 shown in FIG. The air in contact with the end faces 3 and 5 of the rotor core 7 flows along the circular holding member 29 when the rotor 27 rotates. For this reason, according to the rotor 27 of the present invention, the air resistance received by the holding member 29 can be further reduced, so that the above-described effect becomes remarkable.

  It should be noted that the present invention can be carried out in a mode in which various improvements, modifications, or variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. The shape of the core slit is not limited to a circular arc shape, and may extend linearly. The material of the magnet, the material of the rotor core 7, and the use of the electric motor including the rotor 27 do not characterize the present invention.

  Further, the holding member 29 is not necessarily formed on both end faces 3 and 5 of the rotor core 7. The shape of the holding member 29 formed on the end surface 3 is not necessarily the same as the holding member 29 formed on the end surface 5. Two types of holding members selected from a plurality of types of holding members formed by the regions 17 and 25 described in the first to third embodiments are formed on the end surfaces 3 and 5 of one rotor core 7, respectively. May be.

  The present invention may be applicable to an electric motor that drives a compressor or the like of an air conditioner.

  1, 111 ... slit, 3, 5, 123 ... end face, 7, 113 ... rotor core, 9 ... cavity, 11 ... insert mold, 13 ... fixed mold , 15 ... movable mold, 17, 25 ... area, 19, 117 ... spool, 21, 119 ... runner, 23, 121 ... gate, 27 ... rotor, 29, 125 ... holding member, 31, 115 ... magnet, 35 ... both ends, 37 ... range, 39 ... core sheet, 41, 43 ... one end, 45 ... auxiliary region, 101. .. Electric motor, 103 ... rotating shaft, 104 ... shaft hole, 105 ... rotor, 107 ... stator, 109 ... housing.

Claims (4)

A rotor core having a plurality of slits penetrated in an axial direction of a rotating shaft of an electric motor and having an end face in the axial direction is prepared, a magnet is injection-molded into the plurality of slits, and an end face of the rotor core is cut into the plurality of slits. A method for manufacturing a rotor for injection molding a holding member for connecting an injection molded magnet,
Preparing an insert mold in which a magnet having a plastic resin binder from an injection molding machine is supplied to the cavity, and inserting the rotor core into the cavity;
A step in which a magnet supplied from the injection molding machine passes through a region adjacent to an end face of the rotor core of the cavity and is filled into a plurality of slits of the rotor core;
Magnets supplied from the injection molding machine, Ri Do and a step of filling the area of the cavity as the material for forming the holding member,
The rotor, wherein the plurality of slits are spaced apart from each other in the radial direction of the rotating shaft, and the region of the cavity guides a magnet supplied from the injection molding machine in the radial direction. Manufacturing method. A rotor core having a plurality of slits penetrated in an axial direction of a rotating shaft of an electric motor and having an end face in the axial direction is prepared, a magnet is injection-molded into the plurality of slits, and an end face of the rotor core is cut into the plurality of slits. A method for manufacturing a rotor for injection molding a holding member for connecting an injection molded magnet,
Preparing an insert mold in which a magnet having a plastic resin binder from an injection molding machine is supplied to the cavity, and inserting the rotor core into the cavity;
A step in which a magnet supplied from the injection molding machine passes through a region adjacent to an end face of the rotor core of the cavity and is filled into a plurality of slits of the rotor core;
The magnet supplied from the injection molding machine comprises the step of filling the region of the cavity as a material for molding the holding member,
The plurality of slits are spaced apart from each other in the rotation direction of the rotation shaft, and the region of the cavity guides a magnet supplied from the injection molding machine in the rotation direction. Manufacturing method. A rotor core having a plurality of slits penetrated in an axial direction of a rotating shaft of an electric motor and having an end face in the axial direction is prepared, a magnet is injection-molded into the plurality of slits, and an end face of the rotor core is cut into the plurality of slits. A method for manufacturing a rotor for injection molding a holding member for connecting an injection molded magnet,
Preparing an insert mold in which a magnet having a plastic resin binder from an injection molding machine is supplied to the cavity, and inserting the rotor core into the cavity;
A step in which a magnet supplied from the injection molding machine passes through a region adjacent to an end face of the rotor core of the cavity and is filled into a plurality of slits of the rotor core;
The magnet supplied from the injection molding machine comprises the step of filling the region of the cavity as a material for molding the holding member,
The plurality of slits are spaced apart from each other in the rotational direction of the rotary shaft, and the region of the cavity has a ring shape around the rotary shaft of the electric motor. A method of manufacturing a rotor, wherein the method is characterized in that the rotor is guided to flow . The insert molding die is formed with a gate in the cavity region, and the gate is directed to the outermost slit in the radial direction among a plurality of slits spaced from each other in the radial direction. The method for manufacturing a rotor according to claim 1 , wherein a magnet supplied from the injection molding machine is introduced into the cavity.

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