JP6152065B2 - Rotor manufacturing method - Google Patents

Description

  The present invention relates to a rotor manufacturing method.

  In recent years, vehicles equipped with electric motors (motors) for driving vehicles such as fuel cell vehicles, hybrid vehicles, and electric vehicles have been developed one after another. An electric motor generally includes a stator in which a coil is disposed, and a rotor that is rotatably supported around an axis on the inner peripheral side of the stator and in which a magnet is disposed. As the rotor, a so-called IPM (Interior Permanent Magnet) rotor is widely known in which a slot is formed in a rotor core, a magnet is inserted into the slot, and the magnet is embedded in the rotor.

Usually, the magnet inserted into the slot of the rotor core is fixed by solidifying after filling a resin material between the inner wall of the slot and the outer surface of the magnet.
Here, the resin material is roughly classified into a thermosetting resin material and a thermoplastic resin material. Generally, the thermosetting resin material has a lower viscosity than the thermoplastic resin material. Therefore, a thermosetting resin material having a low viscosity and easily penetrating between the inner wall of the slot and the outer surface of the magnet is widely used for fixing the magnet of the IPM rotor.
However, in order to solidify the thermosetting resin material, after filling the slot with the resin material, it is necessary to put the rotor into a heater such as a thermostatic bath and to heat it for a predetermined time until it reaches a predetermined temperature. Therefore, there is room for improvement in terms of shortening the manufacturing process time.

  On the other hand, the thermoplastic resin material can be solidified by natural cooling. Therefore, when a thermoplastic resin material is used for fixing the magnet of the IPM rotor, it is not necessary to heat the slot after filling the resin material in the slot, which is advantageous in terms of shortening the manufacturing process time. However, since the thermoplastic resin material has high viscosity and is easily solidified, it needs to be filled at a high injection speed and high injection pressure. Therefore, the rotor core may be deformed by the pressure of the resin material filled in the slot, which may cause manufacturing defects.

  In order to solve such a problem, for example, Patent Document 1 includes a contact member that contacts part or all of the outer periphery of a laminated iron core (rotor core), and the contact member is sandwiched and fixed by an upper mold and a lower mold. In this state, an injection mold apparatus for filling a resin member (thermoplastic resin material) between a hole (slot) and a magnet is described. According to the technique described in Patent Document 1, the magnet is fixed in a well-balanced manner, and even when resin molding pressure is applied to the laminated iron core during filling of the resin member, the laminated iron core is prevented from being damaged and reliable. It can be improved.

JP 2007-318942 A

  However, in the prior art, since a mold is required to surround the rotor core, there is room for improvement in terms of increasing the size of the manufacturing apparatus and increasing the cost of the manufacturing apparatus.

  Accordingly, the present invention has been made in view of the above circumstances, and can shorten the manufacturing time and prevent the rotor core from being deformed without increasing the size and cost of the manufacturing apparatus and quickly filling the thermoplastic resin material. It is an object of the present invention to provide a rotor manufacturing method that can be used.

In order to solve the above-described problem, a rotor manufacturing method according to the first aspect of the present invention provides a slot for inserting a magnet (for example, a first slot 31, a second slot 32, and a third slot 33 in an embodiment described later). A rotor manufacturing method for manufacturing a rotor (for example, a rotor 3 in a later-described embodiment) having a rotor core (for example, a rotor core 30 in a later-described embodiment), wherein a magnet (for example, The magnet is inserted only from the axial direction of the rotor core without clamping the mold from the radial direction of the rotor core and the magnet insertion step (for example, magnet insertion step S11 in the embodiment described later). perform tightening, filled by injecting a thermoplastic resin material between the inner wall and the outer surface of the magnet of the slot filling step For example, comprise a filling step S13) will be described in the exemplary embodiment, the filling step, the filling the thermoplastic resin material injection speed of the thermoplastic resin material being controlled to be a predetermined constant value After the first filling step (for example, the first filling step S13A in the embodiment described later) and the first filling step, the second filling is performed by filling the thermoplastic resin material while controlling the internal pressure of the thermoplastic resin material. A step (for example, a second filling step S13B in an embodiment described later), and in the filling step, switching between the first filling step and the second filling step is performed by changing the internal pressure and deforming the rotor core. This is performed when a predetermined value set lower than a predetermined upper limit pressure (for example, a predetermined value P in an embodiment described later) is reached .

According to the present invention, in the filling step, since the thermoplastic resin material is filled between the inner wall of the slot and the outer surface of the magnet, it can be solidified without being heated. Therefore, the rotor manufacturing time can be greatly shortened as compared with the case where the thermosetting resin material is filled in the slot and then heated and solidified.
The filling process includes a first filling process for filling the thermoplastic resin material while controlling the injection speed of the thermoplastic resin material, and a thermoplastic resin while controlling the internal pressure of the thermoplastic resin material after the first filling process. A second filling step of filling the resin material, so that the thermoplastic resin material can be quickly filled up to a predetermined filling amount by the first filling step, and a predetermined internal pressure can be obtained by the second filling step. It is possible to prevent deformation of the rotor core by filling the thermoplastic resin material while being controlled. Therefore, the deformation of the rotor core can be prevented and the thermoplastic resin material can be quickly filled without increasing the size and cost of the manufacturing apparatus.

  According to the present invention, since the switching between the first filling step and the second filling step is performed when the internal pressure of the thermoplastic resin material reaches a predetermined value, the time of the first filling step is ensured as long as possible. The slot can be filled with the thermoplastic resin material quickly and the rotor core can be reliably prevented from being deformed.

In the rotor manufacturing method according to the second aspect of the present invention, the thermoplastic resin material filled in the filling step is a liquid crystal polymer.

  According to the present invention, a liquid crystal polymer can be suitably used as the thermoplastic resin material filled in the slot in the filling step.

According to the present invention, in the filling step, since the thermoplastic resin material is filled between the inner wall of the slot and the outer surface of the magnet, it can be solidified without being heated. Therefore, the rotor manufacturing time can be greatly shortened as compared with the case where the thermosetting resin material is filled in the slot and then heated and solidified.
The filling process includes a first filling process for filling the thermoplastic resin material while controlling the injection speed of the thermoplastic resin material, and a thermoplastic resin while controlling the internal pressure of the thermoplastic resin material after the first filling process. A second filling step of filling the resin material, so that the thermoplastic resin material can be quickly filled up to a predetermined filling amount by the first filling step, and a predetermined internal pressure can be obtained by the second filling step. It is possible to prevent deformation of the rotor core by filling the thermoplastic resin material while being controlled. Therefore, the deformation of the rotor core can be prevented and the thermoplastic resin material can be quickly filled without increasing the size and cost of the manufacturing apparatus.

It is a schematic sectional drawing of a motor unit. It is a perspective view of a rotor. It is a top view of a rotor, Comprising: It is an enlarged view of a magnetic pole part. It is a flowchart of the manufacturing process of a rotor. It is explanatory drawing of a magnet insertion process. It is explanatory drawing of a filling process. It is explanatory drawing for demonstrating a 1st filling process and a 2nd filling process. It is a graph showing transition of the injection speed and internal pressure of the thermoplastic resin material in a 1st filling process and a 2nd filling process. It is explanatory drawing of the metal mold | die for filling which concerns on other embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of the motor unit 1.
As shown in FIG. 1, the motor unit 1 includes a motor 4 and a housing 5 that houses the motor 4. In the following description, a direction along the central axis O of the motor 4 is referred to as an axial direction, a direction orthogonal to the central axis O is referred to as a radial direction, and a direction around the central axis O is referred to as a circumferential direction.

The motor 4 is a so-called inner rotor type motor, and includes a cylindrical stator 2, a rotor 3 disposed inside the stator 2, and a shaft 6 that is press-fitted and fixed coaxially with the rotor 3 and rotatably supported. It is equipped with.
The stator 2 has a stator core 20 formed by laminating a plurality of electromagnetic steel plates along the axial direction. The stator core 20 is provided with teeth 21 that extend inward in the radial direction. A coil 23 is wound around the tooth 21 via an insulator 22.

FIG. 2 is a perspective view of the rotor 3.
As shown in FIG. 2, the rotor 3 has a rotor core 30 formed by laminating a plurality of electromagnetic steel plates along the axial direction.
A through hole 30 a is formed at the center of the rotor core 30. In the central portion of the rotor core 30, the shaft 6 (see FIG. 1) is inserted into the through hole 30a and press-fitted and fixed. Moreover, the rotor core 30 has a plurality of lightening portions 30b around the through hole 30a.

The rotor core 30 has a plurality of slot groups 35 arranged at equal intervals over the circumferential direction. The slot groups 35 are provided at eight locations so as to have a pitch of about 45 ° in the circumferential direction on the outer side in the radial direction from the thinned portion 30b.
The slot group 35 includes a first slot 31, a second slot 32, and a third slot 33 (all corresponding to “slots” in the claims). In the first slot 31, the second slot 32, and the third slot 33, magnets 36 described later are respectively inserted.

  In the rotor core 30, a magnetic pole portion 37 is formed by magnetizing the peripheral portion of the slot group 35 by the magnet 36. The rotor 3 of this embodiment is provided with eight slot groups 35 and has eight magnetic pole portions 37 (four pole pairs). The magnetic pole portions 37 adjacent in the circumferential direction are magnetized to different poles by the magnet 36. That is, the magnetic pole portion 37 of the rotor 3 is formed such that the N poles 37A and the S poles 37B are alternately arranged in the circumferential direction.

FIG. 3 is a plan view of the rotor 3, and is an enlarged view of the magnetic pole portion 37.
As shown in FIG. 3, the slot group 35 is formed by a first slot 31 and a second slot 32 and a third slot 33 formed on both sides in the circumferential direction with the first slot 31 interposed therebetween.
The first slot 31 has an isosceles trapezoidal shape in plan view, and is provided so that the longitudinal direction is orthogonal to the radial direction.
An inner wall (hereinafter, referred to as “outer wall 31a”) on the radially outer side of the first slot 31 is recessed in the radially outer side in the middle portion in the longitudinal direction, and a filling groove 31A is formed along the axial direction. Has been. A filling hole 53a (see FIG. 6) of the filling mold 53 is disposed at a position corresponding to the filling groove 31A when the first slot 31 is filled with the thermoplastic resin material in the manufacturing process of the rotor 3 described later. The

A magnet 36 is inserted and arranged in the first slot 31. The magnet 36 is a permanent magnet such as a neodymium magnet, and is formed in a rectangular plate shape. The magnet 36 is also inserted into a second slot 32 and a third slot 33 which will be described later.
The thickness of the magnet 36 along the radial direction is thinner than the width of the first slot 31 along the radial direction. The magnet 36 is disposed in contact with the inner wall (hereinafter referred to as “inner wall 31 b”) in the radial direction of the first slot 31. As a result, a gap 31 c is formed between the radially outer surface of the magnet 36 and the outer wall 31 a of the first slot 31.

  In addition, symmetrical cavities 31d and 31e are formed on both sides of the magnet 36 in the circumferential direction. The volumes of the hollow portions 31d and 31e are substantially the same. The hollow portions 31d and 31e function as a so-called flux barrier that prevents the magnetic flux of the magnet 36 inserted into the first slot 31 from leaking.

  Between the inner wall of the first slot 31 including the gap 31c and the cavities 31d and 31e and the outer surface of the magnet 36, a thermoplastic resin material is filled to form a first mold portion 38A. The first mold portion 38A is formed by filling and solidifying with a thermoplastic resin material in the manufacturing process of the rotor 3 described later. The first mold part 38 </ b> A holds the magnet 36 with respect to the first slot 31. In addition, as a thermoplastic resin which forms 38 A of 1st mold parts, a liquid crystal polymer (Liquid Crystal Polymer: LCP) is suitable.

  The second slot 32 and the third slot 33 each have a trapezoidal shape in a plan view, and are arranged so as to gradually spread from the inner side to the outer side in the radial direction. The second slot 32 and the third slot 33 are formed symmetrically with respect to the first slot 31.

  The outer wall 32a of the second slot 32 is recessed on the outer side in the radial direction on the first slot 31 side with respect to the intermediate portion in the longitudinal direction, and a filling groove 32A is formed along the axial direction. A filling hole 53a (see FIG. 6) of the filling mold 53 is disposed at a position corresponding to the filling groove 32A when the second slot 32 is filled with a thermoplastic resin material in the manufacturing process of the rotor 3 described later. The

  A magnet 36 is inserted into the second slot 32. The magnet 36 is disposed in contact with the inner wall 32 b of the second slot 32. As a result, a gap 32 c is formed between the radially outer surface of the magnet 36 and the outer wall 32 a of the second slot 32.

  In addition, asymmetrical cavities 32d and 32e are formed on both sides of the magnet 36 in the circumferential direction. In the present embodiment, the volume of the cavity 32d on the first slot 31 side (right side in FIG. 3) across the magnet 36 is the cavity on the side opposite to the first slot 31 (left side in FIG. 3) across the magnet 36. It is smaller than the volume of the part 32e. The hollow portions 32d and 32e function as a so-called flux barrier that prevents the magnetic flux of the magnet 36 inserted into the second slot 32 from leaking.

  A space between the inner wall of the second slot 32 including the gap 32c and the cavities 32d and 32e and the outer surface of the magnet 36 is filled with a thermoplastic resin material to form a second mold portion 38B. The second mold portion 38B is formed by filling and solidifying a thermoplastic resin material in the rotor 3 manufacturing process described later. The second mold part 38 </ b> B holds the magnet 36 with respect to the second slot 32. As the thermoplastic resin forming the second mold portion 38B, a liquid crystal polymer (LCP) is suitable as in the first mold portion 38A.

  The third slot 33 is formed symmetrically with the second slot 32. Therefore, the configuration of the filling groove 33A of the third slot 33, the outer wall 33a, the inner wall 33b, the gap 33c, the cavity portions 33d and 33e, and the third mold portion 38C is the same as the filling groove 32A of the second slot 32 described above, Since it is the same as the outer side wall 32a, the inner side wall 32b, the gap 32c, the cavities 32d and 32e, and the second mold part 38B, detailed description is omitted.

As shown in FIG. 1, the housing 5 includes a motor housing 5A that is formed in a substantially cylindrical shape and covers the motor 4, and a sensor housing (not shown) provided on one end side in the axial direction of the motor housing 5A. Yes.
A stator core 20 of the stator 2 is fixed to the motor housing 5A with, for example, a bolt (not shown).
A rotation sensor (not shown) such as a resolver capable of detecting the rotation angle of the rotor 3 is attached to the sensor housing so as to be coaxial with the rotor 3. The sensor housing is provided with a bearing (not shown) that rotatably supports one end of the shaft 6 of the rotor 3. Note that the other end of the shaft 6 of the rotor 3 is rotatably supported by a bearing provided in a transmission housing (not shown) or the like. Thereby, the rotor 3 can be rotated inside the stator 2.

(Rotor manufacturing process)
Next, the manufacturing process of the rotor 3 described above (corresponding to “rotor manufacturing method” in the claims) will be described. In the following description, refer to FIGS. 1 to 3 as necessary for the reference numerals of the respective components.
FIG. 4 is a flowchart of the manufacturing process S10 of the rotor 3.
As shown in FIG. 4, the manufacturing process S10 of the rotor 3 of the present embodiment mainly includes a magnet insertion process S11, a filling process S13, and a solidifying process S15. Below, the detail of each process is demonstrated using drawing. The steps described below are similarly performed at the same timing for each of the first slot 31 to the third slot 33 of the rotor core 30. Therefore, in the following, a process until the magnet 36 is inserted and fixed in the first slot 31 of the rotor core 30 will be described, and the magnet 36 is inserted and fixed in the second slot 32 and the third slot 33. Description of the steps up to this is omitted.

(Magnet insertion step S11)
FIG. 5 is an explanatory diagram of the magnet insertion step S <b> 11 and is a schematic side sectional view including the first slot 31 of the rotor core 30.
As shown in FIG. 5, in the manufacturing process of the rotor 3 of the present embodiment, first, a magnet insertion process S11 is performed.
In the magnet insertion step S11, the positioning part 51a of the pedestal jig 51 is inserted into the through hole 30a of the rotor core 30, and the axial end surface of the rotor core 30 is brought into contact with the pedestal part 51b of the pedestal jig 51. Set with positioning in the axial and radial directions. Subsequently, the magnet 36 is inserted and arranged along the axial direction with respect to the first slot 31 of the rotor core 30. Above, magnet insertion process S11 is complete | finished.

(Filling step S13)
FIG. 6 is an explanatory diagram of the filling step S <b> 13 and is a schematic side sectional view including the first slot 31 of the rotor core 30.
Subsequently, as shown in FIG. 6, a filling step S13 is performed. Below, after explaining the outline | summary of the injection apparatus 50 used by filling process S13, filling process S13 is demonstrated.
The filling step S13 mainly includes the aforementioned base jig 51, a filling mold 53 in which a filling hole 53a is formed, an injection nozzle 60 having a cylinder 61 and a piston 62, an internal pressure measuring pressure sensor 65, It is performed using the injection apparatus 50 provided with.

The filling mold 53 is movable along the axial direction of the rotor core 30 on the side opposite to the pedestal 51b of the pedestal jig 51, for example, by a hydraulic actuator (not shown). The filling mold 53 is pressed by a predetermined pressing force toward the axial end surface of the rotor core 30 so as to be in contact with the axial end surface of the rotor core 30 and not to be separated from the rotor core 30 during filling of the thermoplastic resin material. (So-called mold clamping)
The filling hole 53 a of the filling mold 53 is formed at a position corresponding to the filling groove 31 </ b> A formed in the first slot 31 of the rotor core 30.
Further, a connection hole 53 b to which the injection nozzle 60 is connected is provided at the center of the outer surface of the filling mold 53. The connection hole 53b and the filling hole 53a communicate with each other through a flow path 53c through which the thermoplastic resin material flows.

The injection nozzle 60 is for injecting a thermoplastic resin material into the first slot 31 of the rotor core 30. The injection nozzle 60 is movable along the axial direction of the rotor core 30, and the injection port 60 a at the tip is inserted into the connection hole 53 b of the filling mold 53 when the thermoplastic resin material is filled.
The cylinder 61 has a cylindrical shape and a predetermined volume, and a thermoplastic resin material is supplied to the inside through a supply path (not shown).
The piston 62 can be slid along the axial direction of the cylinder 61 by a hydraulic actuator (not shown), for example.
The injection nozzle 60 is configured so that the injection speed of the thermoplastic resin material becomes a predetermined speed by the piston 62 slidingly moving in the cylinder 61 toward the rotor core 30 side, or from the first slot 31 to the third slot 33. The thermoplastic resin material is injected so that the pressure of the thermoplastic resin material in each slot (hereinafter referred to as “internal pressure”) becomes a predetermined pressure.
The piston 62 is provided with a cylinder pressure sensor 63 capable of detecting the pressure in the cylinder 61 of the thermoplastic resin material at the time of injection.

  On the pedestal 51 b of the pedestal jig 51, an internal pressure measuring pressure sensor 65 is provided at a position corresponding to the first slot 31. The internal pressure measuring pressure sensor 65 measures the internal pressure of the thermoplastic resin material filled in the first slot 31 in the filling step S13. The mounting position of the internal pressure measuring pressure sensor 65 in this embodiment is an example, and if the internal pressure of the thermoplastic resin material filled in the first slot 31 can be measured, the mounting of the internal pressure measuring pressure sensor 65 is performed. The position is not particularly limited.

  The filling step S13 of the present embodiment is a step performed by the injection device 50 configured as described above. The filling step S13 is a step of injecting and filling a liquid crystal polymer, which is a thermoplastic resin material, between the inner wall of the first slot 31 and the outer surface of the magnet 36. The first filling step S13A and the second filling step S13B.

FIG. 7 is an explanatory diagram for explaining the first filling step S13A and the second filling step S13B, and is a schematic side sectional view including the first slot 31 of the rotor core 30. FIG.
FIG. 8 shows the thermoplastic resin material in the first filling step S13A and the second filling step S13B, where the vertical axis is the injection speed or internal pressure of the thermoplastic resin material and the horizontal axis is the injection amount of the thermoplastic resin material. It is a graph showing transition of the injection speed of and internal pressure. 8 is a graph showing the injection speed of the thermoplastic resin material, and the alternate long and short dash line is a graph showing the internal pressure of the thermoplastic resin material measured by the pressure sensor 65 for internal pressure measurement. Further, the pressure of the thermoplastic resin material in the cylinder 61 after the switching point D described later (hereinafter referred to as “in-cylinder pressure Ps”) is indicated by a two-dot chain line.

As shown in FIG. 7, in the filling step S <b> 13, first, the filling mold 53 is moved and pressed (clamped) with a predetermined pressing force toward the axial end surface of the rotor core 30. Subsequently, the injection port 60 a at the tip of the injection nozzle 60 is inserted into the connection hole 53 b of the filling mold 53.
Subsequently, as shown in FIG. 7 and FIG. 8, the first filling step S13A controls the injection speed of the thermoplastic resin material so that the injection speed of the thermoplastic resin material becomes a predetermined constant value. The slot 31 is filled with a thermoplastic resin material. Here, a filling hole 53 a of the filling mold 53 is disposed at a position corresponding to the filling groove 31 </ b> A formed in the first slot 31 of the rotor core 30. Therefore, the magnet 36 disposed in the first slot 31 is pressed radially inward by the internal pressure of the thermoplastic resin material filled in the filling groove 31 </ b> A of the first slot 31, and the inner side of the first slot 31. It contacts the wall 31b.

At this time, the thermoplastic resin material is filled in the first slot 31 while the internal pressure gradually increases as the piston 62 slides toward the rotor core 30 inside the cylinder 61 (see FIG. 8). .
Further, when the first slot 31 is filled with the thermoplastic resin material in the first filling step S13A, the internal pressure of the thermoplastic resin material in the first slot 31 starts to rapidly increase (see FIG. 8). When the internal pressure of the thermoplastic resin material detected by the internal pressure measuring pressure sensor 65 reaches a predetermined value P, the process is switched from the first filling process S13A to the second filling process S13B. Here, the predetermined value P is set to be sufficiently lower than, for example, a predetermined upper limit pressure (the predetermined upper limit pressure P1 in FIG. 8, illustrated by a broken line) at which the rotor core 30 is deformed. The predetermined value P and the predetermined upper limit pressure P1 are set according to the size of the rotor core 30, the strength of the electromagnetic steel sheet forming the rotor core 30, and the like. Hereinafter, a point at which the process is switched from the first filling process S13A to the second filling process S13B is referred to as a switching point D (see FIG. 7).

Subsequently, in the second filling step S13B, the first slot 31 is filled with the thermoplastic resin material while controlling the internal pressure of the thermoplastic resin material in the first slot 31 to maintain the predetermined value P. . At this time, for example, the internal pressure of the thermoplastic resin material is controlled to maintain the predetermined value P by controlling the stroke of the piston 62 so that the cylinder pressure Ps measured by the cylinder pressure sensor 63 is constant. can do.
When the thermoplastic resin material is filled in the first slot 31 by the second filling step S13B, the filling step S13 ends.

Then, solidification process S15 is performed. In the solidification step S15, the thermoplastic resin material filled in the first slot 31 is solidified by natural cooling. Here, when the thermosetting resin material is filled in the first slot 31 in the prior art, for example, the rotor 3 is put into a heater such as a thermostatic bath and heated for a predetermined time until reaching a predetermined temperature. was there. On the other hand, in the present embodiment, since the thermoplastic resin material is filled in the first slot 31, it can be quickly solidified by natural cooling without heating for a predetermined time. Therefore, the manufacturing process for manufacturing the rotor 3 can be simplified and the manufacturing time can be shortened.
When the thermoplastic resin material filled in each slot from the first slot 31 to the third slot 33 is solidified, the solidification step S15 is completed, and the rotor 3 manufacturing step S10 is completed.

According to the present embodiment, in the filling step S13, since the thermoplastic resin material is filled between the inner wall of each slot from the first slot 31 to the third slot 33 and the outer surface of the magnet 36, it is solidified without heating. be able to. Therefore, the manufacturing time of the rotor 3 can be greatly shortened as compared with the case where the thermosetting resin material is filled in each of the first slot 31 to the third slot 33 and then heated and solidified.
In addition, the filling step S13 controls the internal pressure of the thermoplastic resin material after the first filling step S13A for filling the thermoplastic resin material while controlling the injection speed of the thermoplastic resin material, and after the first filling step S13A. And the second filling step S13B for filling the thermoplastic resin material, the first filling step S13A can quickly fill the thermoplastic resin material until a predetermined filling amount is obtained, and the second filling step S13B. Thus, it is possible to prevent deformation of the rotor core 30 by filling the thermoplastic resin material while controlling the pressure to be a predetermined internal pressure. Therefore, the deformation of the rotor core 30 can be prevented and the thermoplastic resin material can be quickly filled without increasing the size and cost of the injection device 50.

  The switching between the first filling step S13A and the second filling step S13B is performed when the internal pressure detected by the internal pressure measuring pressure sensor 65 reaches a predetermined value P. The thermoplastic resin material can be quickly filled into the slots from the first slot 31 to the third slot 33 while ensuring the longest possible time, and the deformation of the rotor core 30 can be reliably prevented.

  In addition, a liquid crystal polymer can be suitably used as the thermoplastic resin material filled in each slot from the first slot 31 to the third slot 33 in the filling step S13.

  The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.

  For example, in the embodiment, the rotor manufacturing method for manufacturing the rotor 3 having the slot group 35 including the first slot 31, the second slot 32, and the third slot 33 has been described. Etc. are not limited to the embodiments.

  For example, in the embodiment, a so-called neodymium magnet mainly composed of neodymium is used as the magnet 36 inserted into each of the first slot 31, the second slot 32, and the third slot 33. The type is not limited to the embodiment. Accordingly, the magnet 36 is, for example, a so-called samarium cobalt magnet whose main material is samarium (Sm), cobalt (Co), or the like, or a so-called material whose main material is aluminum (Al), nickel (Ni), cobalt (Co), or the like. Alnico magnets may be used.

  In the embodiment, the case where the liquid crystal polymer is used as the thermoplastic resin material filled in each slot from the first slot 31 to the third slot 33 has been described. However, each slot is filled. The thermoplastic resin material is not limited to a liquid crystal polymer. Therefore, for example, a thermoplastic resin material other than a liquid crystal polymer such as polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or the like.

  In the embodiment, the injection device 50 includes an internal pressure measurement pressure sensor 65, and when the internal pressure of the thermoplastic resin material detected by the internal pressure measurement pressure sensor 65 reaches a predetermined value P, the first filling is performed. Although the process is switched from the process S13A to the second filling process S13B, the injection device 50 may not include the pressure sensor 65 for measuring internal pressure. For example, the correlation between the filling amount of the thermoplastic resin material into the first slot 31 (that is, the stroke amount of the piston 62) and the internal pressure of the thermoplastic resin material in the first slot 31 is acquired in advance and mapped, and the piston When the stroke amount of 62 reaches a predetermined amount, it may be determined that the internal pressure of the thermoplastic resin material has reached a predetermined value P, and the process may be switched from the first filling process S13A to the second filling process S13B.

(Other embodiments)
In the manufacturing step S10 of the rotor 3 in the above-described embodiment, the case where the first slot 31 is filled with the thermoplastic resin material has been described, but the second slot 32 and the third slot 33 are filled with the thermoplastic resin material. The same can be done for the case. Here, the shapes of the injection nozzle 60, the filling mold 53, and the like constituting the injection apparatus 50 are not limited to the above-described embodiment.

  For example, when the hollow portions 32d and 32e are formed in an asymmetric shape as in the second slot 32 shown in FIG. 3, the following problems remain. That is, when the thermoplastic resin material is filled from the injection nozzle 60 (see FIG. 7) at a position corresponding to the filling groove 32A, the second slot 32 has an asymmetric shape, and therefore, for example, the cavity portion 32d and the cavity portion 32e. Therefore, the flow amount of the thermoplastic resin material is different. Therefore, there is room for improvement in the asymmetrically shaped second slot 32 in that the thermoplastic resin material is surely filled between the inner wall of the second slot 32 and the outer surface of the magnet 36.

FIG. 9 is an explanatory view of a filling mold 53 according to another embodiment, and is a schematic side sectional view including the second slot 32 of the rotor core 30.
Therefore, as shown in FIG. 9, the communication path for easily introducing the thermoplastic resin material into the portion that is difficult to fill with the thermoplastic resin material between the inner wall of the second slot 32 and the outer surface of the magnet 36. (Hereinafter referred to as “flow reader 55”) may be provided.

For example, in this embodiment, when the cavity 32d and the cavity 32e are compared, the cavity 32e is separated from the filling groove 32A rather than the cavity 32d.
In the thermoplastic resin material injected from the injection nozzle 60 toward the filling groove 32A, the gap 32c between the outer surface in the radial direction of the magnet 36 and the outer wall 32a of the second slot 32 serves as a flow path, and the cavity 32d and the cavity The portion 32e is filled. Here, in the gap 32c, the region between the filling groove 32A and the cavity portion 32e has a longer separation distance than the region between the filling groove 32A and the cavity portion 32d, and thus the flow resistance of the thermoplastic resin material. Is high. That is, in this embodiment, the cavity 32e is a portion that is difficult to fill with the thermoplastic resin material.

  The flow leader 55 is formed in a groove shape so as to connect the filling groove 32A and the cavity 32e on the contact surface 53d of the filling mold 53 with the rotor core 30. A part of the thermoplastic resin material injected from the injection nozzle 60 is introduced into the cavity 32 e of the second slot 32 through the flow leader 55. Therefore, according to the filling mold 53 provided with the flow leader 55, it is possible to reliably fill the cavity 32e with the thermoplastic resin material.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

3 Rotor 30 Rotor core 31 First slot (slot)
32 Second slot (slot)
33 Third slot (slot)
36 Magnet S11 Magnet insertion step S13 Filling step S13A First filling step S13B Second filling step

Claims (2)

A rotor manufacturing method for manufacturing a rotor having a rotor core with slots for inserting magnets,
A magnet insertion step of inserting a magnet into the slot of the rotor core;
A filling step of performing mold clamping only from the axial direction of the rotor core without clamping from the radial direction of the rotor core, and injecting and filling a thermoplastic resin material between the inner wall of the slot and the outer surface of the magnet; ,
Including
The filling step includes
A first filling step of filling the thermoplastic resin material while controlling the injection speed of the thermoplastic resin material to be a predetermined constant value;
After the first filling step, a second filling step of filling the thermoplastic resin material while controlling the internal pressure of the thermoplastic resin material;
It includes,
In the filling step, switching between the first filling step and the second filling step is performed when the internal pressure becomes a predetermined value set lower than a predetermined upper limit pressure at which the rotor core is deformed. The rotor manufacturing method characterized by these. The rotor manufacturing method according to claim 1 ,
The rotor manufacturing method, wherein the thermoplastic resin material filled in the filling step is a liquid crystal polymer.

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