JP5232068B2 - Stator manufacturing method - Google Patents

Description

  The present invention relates to a molded motor formed by molding a stator with a mold resin.

In order to dissipate the heat generated by the stator, it is necessary to mold with a molding material. When the stator is molded with a molding material, the molding material is injected at a high pressure, thereby preventing air from being mixed in and preventing air bubbles from being formed.
However, when the mold material is injected at a high pressure, the mold material pressure or the heat of the mold material is applied to the stator, which causes a problem that the molded stator is expanded and deformed. When the stator is enlarged and deformed, the roundness of the stator is deteriorated, which causes a problem in the hybrid motor because it causes cogging and operation accuracy is deteriorated.

Conventionally, as this type of technology, it does not prevent the stator from expanding and deforming, but the following patent is used to suppress the tilting and falling of the protective wall caused by the pressure of the molding material or the heat of the molding material. There is a molded motor 100 (stator) described in Document 1.
FIG. 17 shows a cross-sectional view of the molded motor 100.
The mold motor 100 is provided on the back yoke 111 of the stator 106 perpendicularly to the surface of the back yoke 111, and adjacent to the inner peripheral surface of the protective wall 112 formed in a ring shape. A seat 101 is provided. Further, it is fixed by a mold resin 114 from above.
When the stator 106 is fixed by the mold resin 114, the insert seat 101 is provided adjacent to the inner peripheral surface of the protective wall 112, so that it can withstand the pressure of the mold resin applied to the inner side of the stator 106. be able to.

  The insert seat 101 of the mold motor 100 prevents the protective wall 112 from inclining and falling down. The insert seat 101 attached to the inner side of the protective wall 112 is adjacent to the outer peripheral surface of the protective wall 112. It is also possible to install them. By providing the insert seat 101 on the outer side of the protective wall 112, it is considered that expansion deformation of the outer diameter of the mold motor 100 due to the pressure of the mold resin 114 or the heat of the mold resin 114 can be prevented.

JP 2001-258186 A JP 2003-079113 A JP 2008-160938 A

However, the following problems can be considered in the molded motor 100 in which the insert seat 101 is provided outside the protective wall 112.
That is, the mold motor 100 always requires the insert seat 101 in order to prevent the outer diameter of the mold motor 100 from being enlarged and deformed, leading to high costs.
Further, a molded motor used for a hybrid motor used in an automobile needs to be light in weight in order to improve fuel efficiency. For this reason, if the insert seat 101 that is not directly related to the operation of the motor has to be incorporated at all times, it is contrary to weight reduction.
Furthermore, in the hybrid motor, a filler is mixed in the mold material in order to improve heat conductivity. Filler has better heat transfer, but poor fluidity, so it needs to be high pressure. When the pressure is increased, the flowability of the molding material is poor, and therefore it is necessary to increase the pressure further than before. Therefore, the pressure of the molding material or the heat of the molding material is further applied, so that the stator is enlarged and deformed. Problems that tend to get worse.

  Accordingly, the present invention has been made to solve the above-described problems, and the object thereof is a stator capable of preventing the diameter of the stator from expanding due to the resin injection pressure at the time of molding. An object is to provide a manufacturing method.

In order to achieve the above object, a stator manufacturing method according to the present invention has the following configuration.
(1) In a stator manufacturing method for manufacturing a stator by molding a stator assembly having a plurality of divided stators in a cylindrical member, a thermally expanded fixing ring is inserted into the outer periphery of the stator assembly A first step of fitting the stator ring by cooling, a second step of molding the stator assembly to manufacture the stator, and a third step of thermally expanding the stator ring to remove it from the stator, It is characterized by including.
(2) In the stator manufacturing method described in (1), the thermal expansion coefficient of the fixing ring is larger than the thermal expansion coefficient of the cylindrical member.
(3) In the stator manufacturing method described in (1), the fixing ring presses the stator assembly with a predetermined force.
(4) The stator manufacturing method according to (2) is characterized in that the fixing ring is made of a super duralumin material.

The operation and effect of the stator manufacturing method will be described.
(1) A first step of inserting a thermally expanded fixing ring into the outer periphery of the stator assembly and fitting the stator ring by cooling, and a second step of manufacturing the stator by molding the stator assembly And a third step in which the fixing ring is thermally expanded and removed from the stator, thereby preventing a gap from being generated between the divided stators due to the resin injection pressure when molding, and the stator assembly It is possible to prevent the diameter of the solid from expanding and maintain high roundness.
Further, since the fixing ring can be removed from the stator after molding, the weight of the stator can be reduced.
(2) Since the thermal expansion coefficient of the fixing ring is larger than the thermal expansion coefficient of the cylindrical member, the fixing ring can be easily removed from the stator assembly by thermal expansion.
(3) Since the fixing ring presses the stator assembly with a predetermined force, it is possible to prevent a gap from being generated between the divided stators due to the resin injection pressure at the time of molding, and the stator assembly It is possible to prevent the diameter of the glass from expanding and maintain high roundness.
(4) Since the fixing ring is made of an ultra-duralumin material, the strength of the fixing ring can be increased, and the coefficient of thermal expansion is greater than the coefficient of thermal expansion of the cylindrical member. Can be removed.

It is a front view of the stator 1 in the 1st process (1) which concerns on the present Example 1 of this invention. It is an AA sectional view of stator 1 in the 1st process (1) concerning this example 1 of the present invention. It is a front view of the stator 1 etc. in the 1st process (2) which concerns on the present Example 1 of this invention. It is BB sectional drawing of the stator 1 grade | etc., In the 1st process (2) which concerns on the present Example 1 of this invention. It is a front view of the stator 1 etc. in the 1st process (3) which concerns on the present Example 1 of this invention. It is CC sectional drawing of the stator 1 grade | etc., In the 1st process (3) which concerns on the present Example 1 of this invention. It is sectional drawing of the mold stator 50 grade | etc., In the 2nd process (1) which concerns on the present Example 1 of this invention. It is a front view of mold stator 50 grade in the 2nd process (2) concerning this example 1 of the present invention. It is DD sectional drawing of mold stator 50 grade | etc., In the 2nd process (2) which concerns on the present Example 1 of this invention. It is a front view of mold stator 50 grade in the 3rd process (1) concerning this example 1 of the present invention. It is EE sectional drawing of mold stator 50 grade | etc., In the 3rd process (1) which concerns on the present Example 1 of this invention. It is a front view of the mold stator 50 in the 3rd process (2) which concerns on the present Example 1 of this invention. It is FF sectional drawing of the mold stator 50 in the 3rd process (2) which concerns on the present Example 1 of this invention. 1 is an external perspective view of a stator 1 according to Embodiment 1 of the present invention. It is an external appearance perspective view of the mold stator 50 which concerns on the present Example 1 of this invention. It is a flowchart figure of the manufacturing process of the mold stator 50 which concerns on the present Example 1 of this invention. A sectional view of mold motor 100 concerning patent documents 1 is shown.

Next, an embodiment of specific steps of the method for manufacturing a molded stator according to the present invention will be described in detail with reference to the drawings.
FIG. 16 is a flowchart showing all steps S1 to S14 for manufacturing a molded stator. In the present Example 1, it has a peculiar and remarkable effect in the manufacturing process of the process which concerns on S7-S13.
S7 to S13 can be decomposed in three steps. The process until the fixing ring is heated (S7) and the fixing ring is attached to the stator (S8) is the first step.
Heating before molding (S9) is performed, and mold molding (S10) is set as the second step.
Reheating (S11) and removal of the fixing ring (S12) are defined as the third step.
Specifically, it is a manufacturing method in which the stator 1 shown in FIG. 14 is molded with a mold resin to obtain a molded stator 50 shown in FIG.
1 to 13 sequentially show the first to third steps in the method of manufacturing a molded stator.
Hereinafter, the first to third steps (S7 to S13) and the preliminary steps (S1 to S6) will be described with reference to the drawings.

<Preliminary process>
In the preliminary process, the winding as the conducting wire is wound into a shape that can be engaged with the teeth (S2). An insulator, not shown, is attached to the teeth (S3). A winding is attached to the teeth to form a stator core. After forming the stator cores, 18 stator cores are arranged in a circular shape (S4). The cylindrical member 3 is rubbed against the circularly attached stator core, and the state of the stator 1 in FIG. 14 is obtained (S5). Next, U-phase, V-phase, and W-phase terminals (not shown) are connected (S6).
FIG. 14 shows an external perspective view of the stator 1. The stator 1 includes a cylindrical cylindrical member 3 and 18 stator cores 2 attached inside the cylindrical member 3.
Thus, the preliminary process is completed.

<First step>
The inner periphery and the outer periphery of the stator 1 have high roundness. The outer diameter of the stator 1 is indicated by the stator outer diameter Ds (at room temperature) shown in FIG. The stator outer diameter Ds in the state of FIG. 1 and FIG. 2 is shown as the stator outer diameter Ds (at room temperature) because it shows that at room temperature. In this embodiment, the stator outer diameter Ds (at room temperature) is, for example, 210 mm. The material used for the stator 1 is iron. The linear expansion coefficient of iron is 12.1 × 10 ⁻⁶ / ° C.
The fixing ring 10 shown in FIGS. 3 and 4 uses, for example, an ultra-super duralumin (A7075) material. The linear expansion coefficient of ultraduralumin (A7075) is 23.6 × 10 ⁻⁶ / ° C. Moreover, the yield point stress of ultra super duralumin (A7075) is 49 kg / mm ² .
The inner peripheral wall surface 10A of the fixing ring 10 has high roundness. The inner diameter of the fixing ring 10 is indicated by a ring inner diameter Dr shown in FIGS. The fixing ring 10 shown in FIG.3 and FIG.4 is a thing after a heating, and shows the state expanded thermally.

Although not shown in the drawing, the inner diameter Dr (at room temperature) of the fixing ring 10 before heating is, for example, 210 mm-α in this embodiment. The ring inner diameter Dr is indicated as a ring inner diameter Dr (at room temperature) to indicate that at room temperature. Before the fixing ring 10 is heated, the stator outer diameter Ds of 210 mm is larger, and the fixing ring 10 cannot be inserted into the stator 1.
Therefore, the stator outer diameter Ds (at room temperature)> the ring inner diameter Dr (at room temperature).
The force with which the stator 1 presses the stator 1 from the outer periphery is determined by the magnitude of α. That is, the size of α is a size capable of preventing the stator 1 from being expanded outward by the pressure when the molding resin 60 is pressed at a high pressure during the molding in the second step. The reason is that when the diameter of the stator 1 is increased, the diameter of the inner peripheral surface of the stator 1 is similarly increased, the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the stator 1 is changed, and the torque of the hybrid motor is reduced. Because there is.

The thickness of the fixing ring 10 is 2 mm to 20 mm.
Since the mold clamping force T applied from the top and bottom when the resin molding die 30 in the second step shown in FIG. 7 is molded is 40 tons, the thickness that can secure an area that does not buckle with the force of 40 tons is required to be 2 mm. This is because that.
Further, when the wall thickness is 2 mm, the safety factor is 10 and the wall thickness is 20 mm.
Further, by setting the wall thickness to 2 mm to 20 mm, the strength with which the fixing ring 10 presses the resin molding pressure at the time of resin molding in the second step so as to be less than the deformation amount that the stator 1 can tolerate. Because you can have. The reason why the thickness can be reduced to 2 mm to 20 mm is that the material is made of strong ultra-duralumin.

Next, the fixing ring 10 is heated to about 260 ° C., and the fixing ring 10 is expanded (S7). The fixing ring 10 is thermally expanded by being heated, and expands from the ring inner diameter Dr (at room temperature) to the ring inner diameter Dr (at about 260 ° C.) shown in FIG. The ring inner diameter Dr in the state of FIG. 3 and FIG. 4 is shown as the ring inner diameter Dr (at about 260 ° C.) to indicate that when heated to about 260 ° C.
The stator 1 remains at room temperature without any temperature change.
Therefore, stator outer diameter Ds (at room temperature) <ring inner diameter Dr (at about 260 ° C.).

Next, with the fixing ring 10 heated and thermally expanded, as shown in FIGS. 3 and 4, the fixing ring 10 is inserted and disposed so as to surround the outer periphery of the stator 1. Thereafter, the fixing ring 10 is cooled and brought to a room temperature, so that the fixing ring 10 contracts and is attached to the stator 1 as shown in FIGS. 5 and 6 (S8). Since the fixing ring 10 and the stator 1 have high roundness, the fixing ring 10 can be inserted into the stator 1 even with a slight gap of 1 mm or less.
When the fixing ring 10 is cooled and brought to a normal temperature, the fixing ring 10 contracts and returns to the state before thermal expansion. Therefore, the ring inner diameter Dr (at about 260 ° C.) returns to the same size as the ring inner diameter Dr (at room temperature) before thermal expansion by being cooled.
Therefore, the stator outer diameter Ds (at room temperature)> the ring inner diameter Dr (at room temperature).
By fixing the fixing ring 10 to the stator 1, the fixing ring 10 presses the stator 1 with a predetermined force since the diameter of the fixing ring 10 is smaller than that of the stator 1 at normal temperature. Therefore, the stator core 2 in the stator 1 is also pressed.

<Second step>
In the second step, in the state shown in FIG. 5 and FIG. 6 in which the stator 1 is attached to the fixing ring 10, as shown in FIG. The clamping force T from the top and bottom of the resin mold 30 is 40 ton. A mold resin 60 is poured into the resin mold 30 to form mold dies 31A and 31B for molding the mold resin.
In the state shown in FIG. 7, preheating before molding is performed (S9). This is because by heating the stator 1 before molding, the mold resin 60 is easy to flow and reaches every corner of the stator core 2. The molding temperature is overheated so that the whole is about 140 ° C.

When the pre-molding heating is performed and the stator 1 and the fixed ring 10 reach about 140 ° C., the stator outer diameter Ds (at about 140 ° C.) ≧ the ring inner diameter Dr (at about 140 ° C.).
That is, the stator outer diameter Ds (at room temperature) is expanded by heating, and becomes the stator outer diameter Ds (at about 140 ° C.). Further, the ring inner diameter Dr (at room temperature) also expands when heated to become the ring inner diameter Dr (at about 140 ° C.).
Since the thermal expansion coefficient of the iron having the stator outer diameter Ds is lower than that of the super duralumin of the fixed ring 10, the amount of expansion of the stator outer diameter Ds due to being about 140 ° C. is the diameter of the ring inner diameter Dr of the fixed ring 10. Less than the amount.
Therefore, the stator outer diameter Ds (at about 140 ° C.) ≧ ring inner diameter Dr (at about 140 ° C.).

Next, the stator 1 is molded with the mold resin 60 (S10). Specifically, the mold resin 60 that has been heated and turned into a liquid state is poured into the mold dies 31A and 31B. The mold resin 60 is a resin containing filler. Filler-containing resin enhances heat transfer, but on the other hand, it has poor fluidity and therefore needs to be at a high pressure.
The stator 1 is attached to the fixed ring 10, and the stator outer diameter Ds (at about 140 ° C.) ≧ the ring inner diameter Dr (at about 140 ° C.), and the diameter of the fixed ring 10 is smaller. Is pressed with a predetermined force. Therefore, even if the mold resin 60 flows into the mold dies 31A and 31B in a high pressure state, the outer diameter of the stator 1 is not expanded and deformed because the stator 1 is pressed at a predetermined pressure. The roundness of the inner circumference of the stator 1 can be kept high. Therefore, the expansion deformation of the stator 1 can be prevented.
Further, since the fixing ring 10 is attached to the stator 1, the stator 1 is pressed by the fixing ring 10 with a predetermined force, and the stator core 2 is fixed without a gap. Therefore, it is possible to prevent a gap from being generated between the stator cores 2 when molding.

After the mold resin 60 is poured and reaches every corner in the mold dies 31A and 31B, it is solidified. When the mold resin 60 is solidified on the stator 1, the mold stator 50 is obtained.
After the mold resin 60 is solidified, it is removed from the mold stator 50. 8 and 9 show a state where the resin mold 30 is removed and the mold resin 60 is solidified.
After the resin molding, the fixing ring 10 and the mold stator 50 return to the normal size because they return to room temperature.
Therefore, the stator outer diameter Ds (at room temperature)> the ring inner diameter Dr (at room temperature).

<Third step>
In the third step, the fixing ring 10 is reheated to about 260 ° C. or more again (S11). By reheating, as shown in FIGS. 10 and 11, the fixing ring 10 is thermally expanded. After the re-heating of the fixing ring 10, the stator outer diameter Ds (at about 260 ° C.) <The ring inner diameter Dr (at about 260 ° C.). This is because the thermal expansion coefficient of ultraduralumin of the fixing ring 10 is higher than the thermal expansion coefficient of iron of the mold stator 1.
Therefore, the stator outer diameter Ds (at about 260 ° C.) <The ring inner diameter Dr (at about 260 ° C.).
When reheated, the mold stator 50 is also heated with the fixing ring 10. However, since the mold stator 50 is molded and covered with the mold resin 60 in the second step, the diameter of the mold stator 50 is suppressed from being increased, and the diameter of the mold stator 50 is small. Furthermore, since an air layer exists between the fixing ring 10 and the molded stator 50, there is a thermal resistance, and the molded stator 50 is not heated as much as the fixing ring 10. Therefore, even when heated to about 260 ° C., the molded stator 50 is not heated to about 260 ° C. like the fixing ring 10, and therefore the diameter expansion width of the molded stator 50 is small. Therefore, since the expansion width of the mold stator 50 is small with respect to the fixing ring 10 having a large expansion width, the fixing ring 10 can be easily detached from the mold stator 50.
With the fixing ring 10 thermally expanded, the fixing ring 10 is removed from the stator 1 and removed (S12). By removing the fixing ring 10, the completed molded stator 50 remains as shown in FIGS. An external perspective view of the completed molded stator 50 is shown in FIG.

  By cooling the completed mold stator 50 (S13), all the steps are completed (S14).

As explained in detail above, according to the stator manufacturing method,
(1) A first step in which the thermally expanded fixing ring 10 is inserted into the outer periphery of the stator 1 and the fixing ring 10 is cooled and fitted, and a second step in which the stator 1 is molded and the molded stator 50 is manufactured. And a third step of thermally expanding the fixing ring 10 and removing it from the mold stator 50, thereby preventing a gap from being generated between the stator cores 2 due to resin injection pressure at the time of molding. It is possible to prevent the diameter of 1 from expanding and maintain high roundness.
Moreover, since the fixing ring 10 can be removed from the mold stator 50 after molding, the mold stator 50 can be reduced in weight.
(2) Since the thermal expansion coefficient of the fixing ring 10 is larger than the thermal expansion coefficient of the cylindrical member 3, the fixing ring 10 can be easily detached from the stator 1 by thermal expansion.
(3) Since the fixing ring 10 presses the stator 1 with a predetermined force, it is possible to prevent a gap from being generated between the stator cores 2 due to resin injection pressure at the time of molding. The diameter can be prevented from expanding, and high roundness can be maintained.
(4) Since the fixing ring 10 is made of an ultra-duralumin material, the strength of the fixing ring 10 can be increased, and it does not buckle even with a force of 40 tons. Furthermore, since the thermal expansion coefficient becomes larger than the thermal expansion coefficient of the cylindrical member 3, the fixing ring 10 can be easily detached from the stator 1.

Note that the present invention is not limited to the above-described embodiment, and various applications are possible without departing from the spirit of the invention.
For example, in the embodiment, ultra-duralumin is used for the fixing ring 10, but any material may be used for the fixing ring 10 as long as the thermal expansion coefficient of the fixing ring 10 is larger than the thermal expansion coefficient of the cylindrical member 3.
In the embodiment, the fixing ring 10 has a cylindrical shape, and no groove or the like is formed on the outer periphery thereof. However, the material can be reduced by providing the groove. Even if the groove is formed, the same effect can be obtained.

1 Stator ("stator assembly" in claims)
2 Stator core ("split stator" in claims)
3 Cylindrical member 10 Fixing ring 50 Molded stator ("stator" in claims)
60 Mold resin Ds Stator outer diameter Dr Ring inner diameter

Claims (4)

In a stator manufacturing method of manufacturing a stator by molding a stator assembly having a plurality of divided stators in a cylindrical member,
A first step of inserting a thermally expanded fixing ring on the outer periphery of the stator assembly, and fitting by cooling the fixing ring;
A second step of manufacturing the stator by molding the stator assembly;
A third step of thermally expanding the fixing ring and removing it from the stator;
A stator manufacturing method characterized by comprising: In the stator manufacturing method according to claim 1,
The thermal expansion coefficient of the fixing ring is larger than the thermal expansion coefficient of the cylindrical member;
The stator manufacturing method characterized by these. In the stator manufacturing method according to claim 1,
In the second step, the fixing ring presses the stator assembly with a predetermined force;
The stator manufacturing method characterized by these. In the stator manufacturing method according to claim 2,
The fixing ring is made of ultra-duralumin material;
The stator manufacturing method characterized by these.

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