JP4915098B2 - Manufacturing method of mold motor - Google Patents

Description

  The present invention relates to a method for manufacturing a stator of a molded motor, which is a brushless motor used as a blower fan drive device such as a room air conditioner or a water heater, and forms a motor outer shell by resin integral molding.

  In recent years, increasing the efficiency of electric motors for energy saving is an essential issue as part of environmental measures, and the demand for brushless motors is greatly expanding. Further, reduction of iron loss and copper loss has been pursued as a regular issue for brushless motors to improve efficiency.

  Among them, the approach to high-density winding by dividing the stator core has been widely used as the main method for reducing the copper loss of motors, and the downsizing of motors has also made great progress as a derivative effect. . However, when the core is divided, it is naturally necessary to reassemble the ring again. Since the accuracy of the finished stator product after the annular assembly greatly affects the characteristics of the motor, various approaches for ensuring accuracy have been developed. In particular, the state appears remarkably in the inner diameter accuracy of the annular stator core, and when the inner diameter accuracy deteriorates, torque pulsation such as cogging torque is increased and becomes an important factor for motor noise.

  FIG. 15 shows a pre-molding process of resin integral molding of a conventional mold motor in which the stator winding finished product 30 is mounted in the mold 10. The stator winding finished product 30 is obtained by winding a coil around the developed core 31 shown in FIG. 7 and assembling it annularly as shown in FIG. 8 and temporarily fixing the core by welding or the like. Usually, after an operator or the like inserts a stator winding finished product into a mold die core to a fixed position, the mold is clamped and molded.

  As an approach for improving accuracy, a method is disclosed in which an external pressure is applied from the outer diameter of the stator in the resin integral molding step so that the core inner diameter is adjusted along the center core (for example, refer to Patent Document 1). . On the other hand, there is also disclosed a method of increasing accuracy by stretching an annular stator inner diameter with an expandable inner diameter guide having a slit in a mold (see, for example, Patent Document 3).

In addition, an approach to firmly obtain the rigidity and accuracy of stator annularization before the resin integral molding is disclosed (for example, see Patent Documents 2 and 4). This is because the insulating structure and the shape of the united portion of the core are used to structurally reinforce each other at the stage of stator annularization, thereby producing rigidity and accuracy.
JP 2001-218429 A JP 2002-84698 A Japanese Patent Laid-Open No. 2002-199666 JP 2003-324870 A

However, despite the efforts to improve, the roundness of the finished inner diameter of the resin-integrated stator is actually poor, preventing the occurrence of thin resin burrs on the inner diameter of the finished stator-molded product. In many cases, it is necessary to remove the resin burr by additional processing such as wire buffing or inner diameter cutting in the subsequent process. If this resin burr is not removed, it will drop off during motor operation and cause a motor sound failure. In addition, the presence of the resin burr itself represents a poor roundness of the inner diameter of the core, which leads to torque pulsation of the cogging torque and the like, and even if it is removed, it becomes a hotbed with poor sound.

  Since the mold does not directly pressurize the core with a mold because the mold forms the outer shell of the mold motor, for example, the method of applying external pressure from the outer diameter side toward the inner diameter as in Patent Document 1 may not be adopted. Many. Further, if an expandable inner diameter guide having a slit in the inner diameter of the inner diameter as in Patent Document 3 is adopted, the resin material penetrates into the slit so that the resin material can be penetrated even in a minute gap. It becomes impossible.

  As the original approach, as described in Patent Documents 2 and 4, the roundness of the stator core inner diameter is obtained at the stage of annularization in the finished stator winding product before resin integral molding. Will be the first. However, in recent years, the core yoke width has been limited to the minimum necessary size in order to seek miniaturization and high efficiency. Yes. For this reason, the rigidity after the annularization has been greatly reduced, and it has become impossible to ensure the core inner diameter accuracy of the annular stator winding finished product before the resin integral molding. As a result, it has become inevitable to ensure the core inner diameter accuracy in the final stator finished product process by resin integral molding.

  The present invention is intended to produce a core inner diameter accuracy required by a resin integral molding process in a molded motor that forms a stator finished product by resin integral molding with a miniaturized and highly efficient motor.

In order to solve the above-described conventional problems, the present invention provides a stator core having a ring-shaped yoke and a plurality of teeth disposed on the inner peripheral portion of the yoke. In the method for manufacturing a molded motor, a plurality of protrusions having a leading angle are arranged on the lower mold core of the mold mold, and the stator winding finished product is mounted on the lower mold core of the mold mold. The method of manufacturing a molded motor in accordance with the present invention, and by ensuring that the stator winding finished product is held in the mold, it is possible to establish a method of mounting the stator winding finished product by mold clamping. .

Further, the present invention provides a clearance between the inner diameter of the stator core and the lower mold core of the mold die of 0.02 to 0.06 mm, and improves the roundness of the stator core inner diameter and resin. Can be prevented.

The present invention also provides a method in which a stator winding finished product is temporarily placed on a lower mold center of a mold die, and then the stator winding finished product is moved by a mold clamping operation of the mold die. Attached to the core, the roundness of the inner diameter of the stator core can be improved and the wraparound of the resin can be prevented.

  By improving the roundness of the stator core inner diameter of the molded motor integrally molded with resin and preventing the resin from wrapping around, poor sound due to pulsation of cogging torque, dropping of resin burrs and the like can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1, 2 and 3 are diagrams sequentially showing the resin integrated molding process examples of the present invention. FIG. 1 shows a process of temporarily placing the stator winding finished product 30 on the lower mold core 21. FIG. 2 shows the temporarily placed stator winding finished product 30 by the mold clamping operation of the lower mold. The state where the center core 21 is being pushed in and attached is shown, and the mold stator finished product 40 can be obtained by filling the mold with resin after the upper and lower molds are clamped. The process shown in FIG. 3 is the final process of taking out the molded stator finished product 40 integrally molded with resin.

  In FIG. 1, the stator winding finished product 30 is temporarily placed on the upper part of the lower mold core 21 rather than being attached to a fixed position of the lower mold core 21 by an operator or the like.

  As described above in the background art, conventionally, an operator or the like has mounted the stator winding finished product 30 to the fixed position of the lower mold core 21. This is because in consideration of workability and process stability, the outer diameter of the lower mold core 21 can be easily mounted according to the core inner diameter of the finished stator winding 30.

  In the present invention, since the gap between the lower mold core 21 of the mold 10 and the core inner diameter of the stator winding finished product 30 is minimized, it is not easy to mount the mold mold 10 on the lower mold core 21 easily. It becomes possible. Therefore, it is temporarily placed on the lower mold core 21. Since the stability of the temporarily placed state is an indispensable condition for stabilizing the resin integral molding process, various devices are required.

  FIG. 4 shows a cross-sectional view of the finished mold stator 40. FIG. 5 shows the appearance of the upper part of the lower mold core 21 having the guiding protrusion 211 of the present invention. A major feature of the mold motor is that it can be miniaturized by integrating the outer shell of the motor with a mold. Therefore, the overall length of the motor has been shortened to the minimum necessary. If an introduction guide portion on the cylinder for temporarily supporting the stator winding finished product is provided at the upper part of the lower mold core 21, it will bite into the motor skeleton. The rigidity of the main body of the stator final product 40 is lost. Therefore, by making the guiding protrusion 211 of the limited portion as shown in FIG. 5, it becomes possible to hold the stator winding finished product by the guiding portion, and at the same time as the guiding recess 41 shown in FIG. 4. As a recess, the rigidity of the finished mold stator 40 is not lost.

Regarding the shape of the guiding protrusion 211, the function of the guiding protrusion 211 needs to be able to insert and hold the stator winding finished product 30 with good workability. Therefore, as shown in FIG. 5, the guide protrusion 211 has a guide angle α, and α is set to 1 to 3 degrees, so that both the workability and the holding function can be achieved.

  FIG. 2 shows a specific example of the next process. The temporarily placed stator winding finished product 30 is forcibly mounted to a fixed position of the lower mold core 21 using a mold clamping operation. By pressing the inner mold side resin wall 331 and the outer diameter side resin wall 332 of the stator winding finished product 30 with the upper mold fixing pins 12 arranged at a plurality of locations in the mold clamping operation, the lower mold The center core 21 is pushed into the fixed position.

  In order to locally press the resin wall forming the insulating structure of the stator winding finished product 30 with the upper die fixing pin 12, as shown in FIG. 6, the inner diameter side resin wall 331 of the stator wire finished product 30, Increasing the local thickness of the outer diameter side resin wall 332 and reinforcing it is also an important point to stabilize the process and quality.

  Further, instead of using the upper mold fixing pin 12 as shown in FIG. 2, for example, it is installed on the upper part of the stator winding finished product 30 using a pressing jig or the like, and the pressing jig is fixed by a mold clamping operation. It is also possible to remove the holding jig from the mold and clamp it again to mold the resin integrally after mounting to a fixed position.

  After the mold clamping is completed, a thermosetting unsaturated polyester resin which is a resin material of the mold stator finished product 40 is poured, and after filling, the mold stator finished product 40 which is cooled and cured and integrally molded with the resin is completed. Thereafter, as shown in FIG. 3, it is separated from the lower mold core 21 by being ejected by an ejector pin 22 and taken out from the mold 10.

  9, FIG. 10 and FIG. 11 are diagrams sequentially showing an example of resin integral molding by outer setup mounting of the finished stator winding 30 of the present invention.

  FIG. 9 shows a process in which the finished stator winding 30 is temporarily placed on the lower mold core 21 of the removed mold, and is pushed into the fixed position of the lower mold core 21 via the holding jig 50 and attached. FIG. 10 shows a state in which the preheated stator winding finished product 30 and the lower mold core 21 are assembled in the mold. FIG. 11 shows the final process of separating the lower mold core 21 from the finished mold stator 40 taken out of the mold.

  In FIG. 9, the stator winding finished product 30 taken out of the mold 10 is not mounted to a fixed position of the lower mold core 21 by an operator or the like, but temporarily attached to the upper part of the lower mold core 21. Place it. As described above in the first embodiment, in the present invention, since the gap between the lower mold core 21 of the mold 10 and the core inner diameter of the stator winding finished product 30 is minimized, It becomes impossible to attach to the core 21. Therefore, it is temporarily placed on the lower mold core 21 and is mounted to a fixed position through the holding jig 50 installed on the upper part of the stator winding finished product 30 that has been temporarily placed in the next step.

  In FIG. 10, the lower mold core 21 having the stator winding finished product 30 mounted to a fixed position is incorporated into a mold.

  After the mold clamping is completed in the next step, a thermosetting unsaturated polyester resin that is a resin material of the finished mold stator product 40 is poured, and after filling, cooling, and curing, a stator mold that is integrally molded with resin is completed. The product 40 is taken out from the mold 10 while being attached to the lower mold core 21.

  As shown in FIG. 11, the finished mold stator 40 is extruded and separated from the lower mold core 21.

  Separating the lower mold core and assembling the process requires a technique to fasten the lower mold core to the mold, but by allocating the work that requires a lot of man-hours in the molding process to the external setup, There is an advantage that the mounting to the mold can be easily processed, and it becomes easy to consider and cope with the quality of the workpiece at the mounting / demounting stage.

  FIG. 12 is a graph showing the relationship between the clearance between the lower mold core outer diameter and the stator core inner diameter and motor noise. FIG. 13 is a graph showing the relationship between the gap between the outer diameter of the lower mold core and the stator core inner diameter, and the roundness of the inner diameter of the finished mold stator core.

  As can be seen from FIG. 12, the motor noise has clearly increased since the gap between the lower mold core of the mold and the core inner diameter of the finished stator winding is around 0.06 mm. Further, as can be seen from FIG. 13, if the gap between the outer diameter of the lower mold core and the inner diameter of the stator core is reduced, the effect of correcting the inner diameter of the stator core is brought about. Will improve the roundness. The relationship between roundness and motor noise has been pointed out in the past, and from this result, the inner diameter dimension of the finished annular stator winding after resin molding and the accuracy of roundness Increasing the noise leads to a reduction in noise.

  FIG. 14 is a graph showing the relationship between the gap between the outer diameter of the lower mold core and the inner diameter of the finished stator winding and the occurrence of resin burrs at the inner diameter of the finished mold stator core. Regarding the numerical value as an index, since the stator core having 12 teeth is used this time, the number of teeth in which resin burrs are generated on the inner diameter surface of the teeth in 12 teeth is expressed as a ratio. The resin material used is a thermosetting unsaturated polyester resin. The clearance between the outer diameter of the lower mold core and the inner diameter of the finished stator winding will allow the resin to enter if it exceeds a certain dimension, and will appear as the occurrence of an inner diameter burr in the finished stator winding. The inner diameter burr has a possibility of dropping every time, and causes motor noise due to contact with the rotor during motor rotation.

  From FIG. 14, it can be seen that a gap between the outer diameter of the lower mold core and the inner diameter of the finished stator winding is around 0.07 mm, and the inner diameter resin burr of the finished mold stator is noticeably generated. . It is necessary to operate gaps in a range where resin penetration is suppressed.

  As shown in FIGS. 7 and 8, the stator winding finished product 30 is in a temporarily fixed state for integration by annularizing the developed core, and the lower core is unnecessarily attached to the lower core. If the clearance between the outer diameter of the stator and the inner diameter of the finished stator winding is reduced, the temporarily fixed state may be disassembled. Moreover, the excessive strong fitting will make it difficult to separate from the lower core mold as a finished mold stator. A certain gap between the outer diameter of the lower mold core and the inner diameter of the finished stator winding is an indispensable element for establishing resin integral molding as a mass production process.

  Positioning the gap as an indispensable element to be established as a mass production process, and inserting the gap between the inner diameter of the finished stator winding product and the lower mold core of the mold, considering the results of FIGS. The gap was set to 0.02 to 0.06 mm. As a result, in the resin integral molding process, the mold that suppresses the occurrence of stator core roundness and inner diameter burrs that affect the mold motor noise without causing problems such as disassembly of the finished stator winding and inability to attach and detach. A finished stator can be obtained.

The method for manufacturing a molded motor according to the present invention has a great effect particularly on a motor that is difficult to obtain a stator assembly accuracy such as a split core. In the meantime, the same effect is exhibited in a situation where the rigidity of the core is narrowing. Applications of mold motors, such as pump motors that require confidentiality, are becoming widespread, and can be widely used as manufacturing methods that can easily obtain the stator core inner diameter roundness.

The figure which shows the process which temporarily set | placed the stator winding completion product in Example 1 of this invention on the lower mold | type core. The figure which shows the process of mounting | wearing a stator winding finished product to a lower mold | type core with the mold clamping in Example 1 of this invention. The figure which shows the process of taking out the mold stator completed product integrally molded in Example 1 of this invention Cross section of the finished mold stator External view of lower mold core having the guiding protrusion of the present invention Diagram showing local reinforcement of resin wall of finished stator winding The figure which shows the deployment core which coil winding is done Diagram showing the finished stator winding The figure which shows the process of mounting | wearing the lower mold | type core with the stator winding finished product in Example 2 of this invention. The figure which shows the process of mounting | wearing a metal mold | die with the lower mold | type core which mounted | wore with the stator winding finished product in Example 2 of this invention. The figure which shows the process of taking out the mold stator finished product by which resin integral molding in Example 2 of this invention was carried out A graph showing the relationship between the motor noise and the clearance between the lower mold core outer diameter and stator core inner diameter Graph showing the relationship between the gap between the outer diameter of the core of the lower mold and the inner diameter of the stator core and the presence or absence of the inner diameter resin burr A graph showing the relationship between the gap between the outer diameter of the core of the lower mold and the inner diameter of the stator core and the roundness of the inner diameter of the finished mold stator core The figure which shows before the mold of the stator winding finished product installed in the conventional mold

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold metal mold | die 12 Upper mold fixing pin 21 Lower mold center core 211 Guide projection part 22 Ejector pin 30 Stator winding completed product 31 Expanded core 331 Inner diameter side resin wall 332 Outer diameter side resin wall 40 Mold stator final product 41 Invitation Recess 50 Holding jig

Claims (3)

In a manufacturing method of a molded motor, a winding is applied to an annular yoke and a stator core having a plurality of teeth arranged on the inner peripheral portion of the yoke, and an outer portion of the motor is formed by resin integral molding.
A method for manufacturing a molded motor, wherein a plurality of protrusions having a leading angle are arranged on a lower mold core of a mold , and a finished stator winding is mounted on the lower mold core of the mold. 2. The method for manufacturing a molded motor according to claim 1, wherein a gap between an inner diameter of the stator core and a lower mold core of the mold is 0.02 to 0.06 mm. After temporarily placing the stator winding finished product on the lower mold center of the mold, the stator winding finished product is placed on the lower mold core of the mold by a mold clamping operation of the mold. method for producing a molded motor according to claim 1 or 2, characterized in that mounting.

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