JP5179949B2 - Manufacturing method and apparatus for cage rotor - Google Patents

Description

  The present invention relates to a method and apparatus for manufacturing a squirrel-cage rotor die-cast with molten metal.

A squirrel-cage rotor of an induction motor is usually manufactured by die casting using a molten metal such as molten aluminum. This manufacturing apparatus is provided with a mold for housing a rotor core having a plurality of slots on the outer periphery, and the molten aluminum is supplied into the mold from its gate to accommodate in each slot of the stator core. A short-circuit ring that short-circuits both ends of the plurality of conductors is integrally formed on both end surfaces in the axial direction of the plurality of conductors and the rotor core (see, for example, Patent Document 1).
JP-A-6-133506

  In the cage rotor, since the cross-sectional area of the short-circuited ring portion is larger than the cross-sectional area of the slot portion, the molten aluminum in the slot portion solidifies first, and then the molten aluminum in the short-circuited ring portion solidifies. Thus, a sinkhole is likely to occur in the short-circuit ring. In order to prevent the occurrence of such a shrinkage nest, it is conceivable to employ a local pressure die casting method in which the shorted ring portion is directly pressurized before the molten aluminum filled in the shorted ring portion is solidified. However, although it is easy to provide a pressurizing device that pressurizes the short-circuited ring portion on the side of the mold that does not have a sprue, it is difficult to provide a pressurizing device on the side that has a spout to which molten aluminum is supplied.

  The present invention has been made in view of the above circumstances, and an object thereof is a cage shape that can easily pressurize a short-circuited ring portion formed on both end surfaces in the axial direction of a rotor core during die casting with a molten metal. It is providing the manufacturing method and apparatus of a rotor.

  The method for manufacturing a cage rotor of the present invention accommodates a rotor core having a plurality of slots on the outer peripheral portion, and a cavity for forming a short-circuit ring that communicates with the slots on both axial end surfaces of the rotor core. And a mold having a gate plate having a gate communicating with one of the two cavities in opposition to each other, and an injection plunger for extruding the molten metal. A supply device that supplies the one cavity of the mold through the gate of the mold, and the molten metal filled in the other of the two cavities is solidified by the pressurizing means before solidifying. The gate is applied by applying a pressing force to the injection plunger of the supply device before the molten metal filled in the one cavity is solidified. Plate is moved from the normal position, characterized in that pressurizing the molten metal filled in the one cavity.

  A squirrel-cage rotor manufacturing apparatus according to the present invention accommodates a rotor core having a plurality of slots on its outer peripheral portion, and a cavity for forming a short-circuit ring that communicates with the slots on both axial end surfaces of the rotor core. And a mold having a gate plate having a gate communicating with one of the two cavities in opposition to each other, and an injection plunger for extruding the molten metal. A supply device that supplies the one cavity of the mold through the gate of the mold and the other of the two cavities, and is provided before the molten metal filled in the cavity is solidified. A pressurizing means for pressurizing the molten metal and the gate plate are held in a normal position when the molten metal is supplied, and one of the two cavities is keyed. Holding means for releasing the holding of the gate plate before the molten metal filled in the bite solidifies, and when the holding of the gate plate by the holding means is released, the injection plunger of the supply device The gate metal is moved by applying a pressing force to pressurize the molten metal filled in the one cavity.

  According to the present invention, in the cavity for forming the short-circuit ring on both end faces of the rotor core, the molten metal filled in one cavity is pressurized using the gate plate and filled in the other cavity. Since the molten metal is pressurized by a normal pressurizing means, it is possible to easily pressurize the short-circuited ring portion before solidification and reliably prevent the occurrence of a sinkhole in the short-circuited ring.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 3 shows a cage rotor 1 of an induction machine, for example, an induction motor. The squirrel-cage rotor 1 includes a rotor core 2 formed by laminating a large number of annular cores made of silicon steel plates. A plurality of slots 2a extending in the axial direction are formed on the outer peripheral portion of the rotor core 2 at a predetermined interval, for example, a constant interval in the circumferential direction, and each slot 2a has an aluminum column shape. An eggplant conductor 3 is inserted.

  The both ends of the rotor core 2 in the axial direction are provided with aluminum short-circuit rings 4 and 5, and both ends of the plurality of conductors 3 in the axial direction are short-circuited. . A shaft hole 6 is formed at the center of the rotor core 2, and a rotating shaft 7 is inserted and fixed in the shaft hole 6.

  In the cage rotor 1 having such a configuration, the aluminum conductor 3 and the short-circuit rings 4 and 5 are integrally formed by aluminum die casting. Hereinafter, the manufacturing apparatus 8 for performing the aluminum die casting will be described. This will be described with reference to FIGS.

  The mold 9 includes a fixed mold 10 and a movable mold 11 that can be attached to and detached from the fixed mold 10. The movable mold 11 includes an intermediate mold 12 having a cavity 12a for housing the rotor core 2 of the cage rotor 1, a right mold 13 having a cavity 13a for molding the short-circuit ring 4 on one side, and a mold on the other side. It consists of a left mold 14 having a cavity 14a for molding the short ring 5. The right mold 13 and the left mold 14 are detachably attached to the right end and the left end of the intermediate mold 12 in a state where the rotor core 2 is housed in the cavity 12a. In this case, the cavity 13 a of the right mold 13 and the cavity 14 a of the left mold 14 communicate with the slot 2 a of the rotor core 2. Further, a shaft-like fitting member 15 is inserted into the shaft hole portion 6 of the rotor core 2, and the right mold 13 is formed with a recess 13 b that fits with the head portion 15 a of the fitting member 15. In the left mold 14, a recess 14 b that fits with the left end of the fitting member 15 is formed.

  The gate plate 16 is detachably mounted in the right mold 13 so as to be movable in the left-right direction, and a runner 17 is formed between the gate plate 16 and the fixed mold 10. As will be described later, the gate plate 16 integrally has a gate portion 16a facing the cavity 13a of the right mold 13 at a normal position, and a plurality of gates 16b communicating with the cavity 13a are formed in the gate portion 16a. Has been.

  A plurality of holding pins 18 are inserted into the movable die 11 so as to be movable in the left-right direction, and a large-diameter portion 18a at the base end portion is fitted into the concave portion 14c of the left die 14. The holding pin 18 is restricted from moving in the right direction by the right end surface of the large-diameter portion 18a coming into contact with the stepped portion 14d of the recess 14c. At this time, the front end surface contacts the left end surface of the gate plate 16. The gate plate 16 is held in contact with the normal position. When the gate plate 16 is held at the normal position, there is a predetermined interval between the gate plate 16 and the wall portion 13c of the right mold 13. In this case, the large-diameter portion 18a of the holding pin 18 is given a driving force in the right direction by a hydraulic cylinder (not shown). When the driving force is released, the holding pin 18 can move in the left direction. Become. Here, the holding pin 18 and the hydraulic cylinder constitute a hydraulic mechanism as holding means.

  A fitting hole 14e communicating with the cavity 14a is formed at the center of the left mold 14. The fitting hole 14e has a discontinuous substantially annular shape in which the annular hole is divided into a plurality of, for example, two. In this fitting hole 14e, a pressurizing body 19 as pressurizing means having a shape obtained by dividing the short cylindrical body into two is fitted so as to be movable in the left-right direction. The left half of the pressurizing body 19 is formed in the small diameter portion 19a. The pressurizing body 19 is moved in the right direction when the right end surface of the small diameter portion 19a abuts the step portion 14f of the fitting hole 14e. Movement is regulated. The pressurizing body 19 is connected to a piston lot 20 of a hydraulic cylinder, and the right end surface of the small diameter portion 19a is always held at a normal position with a predetermined distance from the step portion 14f. When pressed by the rod 20, it is moved to the right.

  The supply device 21 includes an injection sleeve 22 attached to the fixed mold 10 of the mold 9, and a tip end portion of the injection sleeve 22 communicates with the runner 17 of the mold 9. An injection plunger 23 is mounted in the base end portion of the injection sleeve 22. The injection plunger 23 is moved in the left-right direction by a hydraulic cylinder (not shown) as will be described later.

Next, the operation of this embodiment will be described.
The rotor core 2 is formed by laminating a large number of iron core materials, and the iron core material is formed by punching a band-shaped silicon steel plate with a press. In order to improve the punchability at the time of press punching, it is usual that punching oil is applied to the band-shaped silicon steel plate, but this punching oil adheres to the punched iron core material. Therefore, in this embodiment, the rotor core 2 is heated at a predetermined temperature, for example, 300 to 400 ° C., and punching oil is burned (iron core oil firing).

  Next, as shown in FIG. 1, the mold 9 is assembled in a state where the rotor core 2 is housed in the cavity 12 a of the intermediate mold 12, and molten aluminum 24 that is a molten metal is placed in the injection sleeve 22 of the supply device 21. Is supplied and stored. Thereafter, the injection plunger 23 is driven to move leftward by the hydraulic cylinder of the supply device 21, and the molten aluminum 24 is pushed out of the injection sleeve 22 by the injection plunger 23, and the cavity 13a, via the runner 17 and the gate 16b, The slot 2a and the cavity 14a are sequentially supplied and filled. In this case, when the molten aluminum 24 is pushed out by the injection plunger 23, a leftward pressing force is applied to the gate plate 16. At this time, the gate is held by the holding pin 18 receiving the rightward pressing force by the hydraulic cylinder. The plate 16 is held in the normal position. Further, the pressure body 19 is also subjected to a leftward pressing force by the molten aluminum 24 supplied to the cavity 14a of the left mold 14. At this time, the pressure body 19 is actuated by the hydraulic cylinder to the right end of the small diameter portion 19a. The surface is held at a normal position having a predetermined distance from the step portion 14f.

In this way, after the molten aluminum 24 is filled into the mold 9, the mold 9 is cooled (natural cooling or forced cooling), and solidification of the molten aluminum 24 filled in the mold 9 is started. The
In this case, in the cage rotor 1, since the cross-sectional area of the short-circuit rings 4 and 5 is larger than the cross-sectional area of the slot 2a portion, the molten aluminum 24 in the slot 2a portion solidifies first, and then the short-circuit ring. Since the molten aluminum 24 in the 4th and 5th parts is solidified, a sinkhole is easily generated in the short-circuited rings 4 and 5.

  Therefore, in this embodiment, the molten aluminum 24 in the slot 2a portion solidifies first, and then the holding pin by the hydraulic cylinder is in a semi-solid state, for example, before the molten aluminum 24 in the short-circuit rings 4 and 5 portion solidifies. 18 is released, and the pressing force by the injection plunger 23 of the supply device 21 is applied. At this time, since the molten aluminum 24 in the runner 17 and the injection sleeve 22 is also in a semi-solid state, the pressing force by the injection plunger 23 acts on the gate plate 16 via the semi-solid state molten aluminum 24. The plate 16 moves leftward from the normal position, and the gate portion 16a presses the molten aluminum 24 in the cavity 13a of the right mold 13. At this time, the holding pin 18 is also pressed by the gate plate 16 and moves leftward. As shown in FIG. 2, the left end surface of the gate plate 16 comes into contact with the wall 13c of the right mold 13 and stops moving in the left direction.

  At the same time, the repressing cylinder applies a pressing force in the right direction to the pressurizing body 19 via the piston rod 20, and the pressurizing body 19 is driven in the right direction to melt in the cavity 14a of the left mold 14. The aluminum 24 is pressurized. As shown in FIG. 2, the right end surface of the small diameter portion 19 a comes into contact with the step portion 14 f of the left mold 14, and the pressure body 19 stops moving in the right direction.

  If the molten aluminum 24 in the mold 9 is completely solidified, the movable mold 11 is removed from the fixed mold 10, and then the movable mold 11 is disassembled, and the semi-finished product of the cage rotor 1 is taken out. Here, the semi-finished product of the squirrel-cage rotor 1 means a state in which the rotary shaft 7 is not provided in the squirrel-cage rotor 1 shown in FIG. Is formed. Then, the rotary shaft 7 is inserted and fixed in the shaft hole portion 6 of the rotor core 2, whereby the cage rotor 1 is completed (completed product).

  As described above, according to the present embodiment, in the mold 9, the molten aluminum 24 in the cavity 13 a of the right mold 13 located on the runner 17 side that is the pouring gate side is pressurized by the gate portion 16 a of the gate plate 16. Since the molten aluminum 24 in the cavity 14a of the left mold 14 located at the position is pressed by the pressurizing body 19 which is a normal pressurizing device, both the short-circuited rings 4 and 5 in the semi-solidified state before solidification are melted. 24 can be pressurized, and it is possible to reliably prevent the occurrence of a sinkhole in the short-circuit rings 4 and 5.

  According to the present embodiment, as described above, the semi-solid molten aluminum 24 in the cavity 13a of the right mold 13 which is the gate side is pressurized by the gate plate 16, so There is no need to provide a special pressure device, and the molten aluminum 24 in the cavity 13a of the right mold 13 on the side of the gate can be easily pressurized.

  In the above embodiment, when the holding pin 18 and the gate plate 16 are connected and the gate plate 16 is moved to the left by the pressing force of the injection plunger 23 of the supply device 21, the holding pin 18 is driven by the hydraulic cylinder. A driving force in the left direction may be applied to the gate plate 16 via

(Second embodiment)
4 and 5 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.
In the second embodiment, a movable plate 25 is disposed between the wall portion 13c, which is a stationary part of the right mold 13, and the gate plate 16 instead of the holding pin 18. It is provided so as to be able to advance and retreat in the radial direction with respect to the peripheral wall. The movable plate 25 is driven by a hydraulic cylinder (not shown). The movable plate 25 always moves forward and is positioned between the wall 13c of the right mold 13 and the gate plate 16 so that the gate plate 16 is moved. The normal position is maintained, and when it is driven radially outward by the hydraulic cylinder, it moves backward and separates from between the wall 13c of the right mold 13 and the gate plate 16. Here, the movable plate 25 and the hydraulic cylinder constitute holding means.

Thus, as shown in FIG. 4, in the state where the movable plate 25 is in the forward movement position, the injection plunger 23 of the supply device 21 pushes out the molten aluminum 24 to supply and fill the mold 9 as described above. This is the same as the example, and thereafter, the movable plate 25 is controlled to move backward to be in the state shown in FIG.
Therefore, the second embodiment can provide the same effects as those of the previous embodiment, and in particular, the structure of the movable plate 25 as the holding means is simple.

(Third embodiment)
6 and 7 show a third embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be described below.
In the third embodiment, a laminated thickness correcting mechanism 26 for correcting the laminated thickness of the rotor core 2 is provided. The stacking thickness correcting mechanism 26 is movable in the left-right direction with respect to the pressing body 27 that presses the left end surface in the axial direction of the rotor core 2, the pressing body 19 attached to the pressing body 27, and the left mold 14. And a compression spring 29 interposed between the driving body 28 and the pressing body 27. A piston rod 30 of a hydraulic cylinder is connected to the drive body 28, and the drive body 28 always holds the pressure body 19 in a normal position with the right end surface in contact with the left end surface of the pressure body 19. It is supposed to be. In this state, a predetermined interval exists between the right end surface of the driving body 28 and the left end surface of the pressing body 27.

  When the driving body 28 receives a pressing force in the right direction by the hydraulic cylinder, the driving body 28 moves the pressure body 19 in the right direction so that the right end surface thereof comes into contact with the left end surface of the pressing body 27. The axial right end surface of the rotor core 2 is in contact with the step portion 13d of the wall portion 13c of the right mold 13. As is clear from this, the pressurizing body 19 serving as the pressurizing means is incorporated in the laminated thickness correcting mechanism 26.

  Thus, as shown in FIG. 6, when the molten aluminum 24 is supplied and filled into the mold 9, the pressing body 27 receives the urging force of the compression spring 29 and presses the left end surface of the rotor core 2. The laminated thickness dimension of the rotor core 2 is corrected to a predetermined dimension L. In such a state, molten aluminum 24 is supplied and filled into the mold 9 by the injection plunger 23 of the supply device 21.

  Thereafter, as shown in FIG. 7, in the mold 9, the molten aluminum 24 in the slot 2a portion is completely solidified, and the molten aluminum 24 in the short ring 4 and 5 portions (cavities 13a, 14a) is in a semi-solid state. Sometimes, as in the first embodiment, the gate plate 16 is moved leftward from the normal position, and at the same time, the driving body 28 is driven rightward by the hydraulic cylinder, and the pressurizing body 19 is the cavity 14a of the left mold 14. The molten aluminum 24 inside is pressurized. In this case, since the molten aluminum 24 filled in the slot 2a of the rotor core 2 is completely solidified and fixed, the rotor core 2 is further moved by the driver 28 via the pressing body 27 as described above. Even if pressed, the lamination thickness dimension L of the rotor core 2 does not change.

  Therefore, the same effect as that of the first embodiment can be obtained by this third embodiment. In particular, in this third embodiment, the pressurizing body 19 is incorporated in the lamination thickness correcting mechanism 26, so The hydraulic cylinder of the thickness correction mechanism 26 can also be used as a drive source for the pressurizing body 19, and there is no need to provide a dedicated drive source for the pressurizing body 19.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following changes and modifications can be made without departing from the scope of the invention.
As the molten metal, molten copper may be used in addition to molten aluminum.
What is necessary is just to perform the oil baking of the iron core before die-casting as needed.
The present invention can be applied not only to induction motors but also to induction machines in general.

The longitudinal cross-sectional view of the manufacturing apparatus which shows 1st Example of this invention FIG. 1 equivalent diagram for explaining the operation Perspective view of cage rotor FIG. 1 equivalent view showing a second embodiment of the present invention. 2 equivalent diagram FIG. 1 equivalent view showing a third embodiment of the present invention. 2 equivalent diagram

Explanation of symbols

In the drawings, 1 is a squirrel-cage rotor, 2 is a rotor core, 2a is a slot, 3 is a conductor, 4 and 5 are short-circuited rings, 6 is a shaft hole, 7 is a rotating shaft, 8 is a manufacturing device, and 9 is gold. Mold, 10 is a fixed mold, 11 is a movable mold, 12 is an intermediate mold, 12a is a cavity, 13 is a right mold, 13a is a cavity, 13c is a wall (stationary part), 14 is a left mold, 14a is a cavity, 16 is Gate plate, 16a is a gate portion, 16b is a gate, 18 is a holding pin (holding means), 19 is a pressurizing body (pressurizing means), 21 is a supply device, 22 is an injection sleeve, 23 is an injection plunger, and 24 is molten. Aluminum (molten metal), 25 is a movable plate (holding means), 26 is a lamination thickness correcting mechanism, 27 is a pressing body, 28 is a driving body, and 29 is a compression spring.

Claims (6)

A rotor core having a plurality of slots on the outer peripheral portion is housed, and a cavity for forming a short-circuited ring that communicates with the slot is provided on both end surfaces in the axial direction of the rotor core. A mold with a gate plate having a gate communicating opposite the cavity;
An injection plunger for extruding the molten metal, and a supply device for supplying the molten metal to the one cavity of the mold through the gate of the gate plate by the extrusion,
Before the molten metal filled in the other of the two cavities solidifies, the molten metal is pressurized by a pressurizing means, and before the molten metal filled in the one cavity solidifies, A method of manufacturing a squirrel-cage rotor, wherein the gate plate is moved from a normal position by applying a pressing force to an injection plunger to pressurize molten metal filled in the one cavity. A rotor core having a plurality of slots on the outer peripheral portion is housed, and a cavity for forming a short-circuited ring that communicates with the slot is provided on both end surfaces in the axial direction of the rotor core. A mold with a gate plate having a gate communicating opposite the cavity;
A supply device comprising an injection plunger for extruding molten metal, and supplying the molten metal to the one cavity of the mold through the gate of the gate plate by the extrusion;
A pressurizing means provided to face the other of the cavities and pressurizing the molten metal before the molten metal filled in the cavity is solidified;
Holding means for holding the gate plate in a normal position when supplying the molten metal, and releasing the holding of the gate plate before the molten metal filled in one of the cavities solidifies. ,
When the holding of the gate plate by the holding means is released, the molten metal filled in the one cavity by moving the gate plate from the normal position by applying a pressing force to the injection plunger of the supply device An apparatus for manufacturing a squirrel-cage rotor that pressurizes the rotor.   3. The cage rotor manufacturing apparatus according to claim 2, wherein the holding means is constituted by a hydraulic mechanism.   4. The squirrel-cage rotor manufacturing apparatus according to claim 3, wherein the hydraulic mechanism drives the gate plate in the cavity direction simultaneously with the release of the holding of the gate plate.   3. A squirrel-cage rotor manufacturing apparatus according to claim 2, wherein the holding means comprises a movable plate which is movable between a gate plate and a stationary part and which is movable back and forth.   3. A squirrel-cage rotor manufacturing apparatus according to claim 2, wherein the pressurizing means is incorporated in a lamination thickness correcting mechanism for correcting the lamination thickness by pressing the rotor core.

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