Reactor and method for manufacturing the same

Abstract

The present disclosure relates to a reactor and a manufacturing method thereof. The reactor is provided with a coil, a gap being ensured between adjacent windings; a core, inserted through the coil; and a heat sink, in contact with a side surface of the coil. The heat sink is inserted between the adjacent windings of the coil. Further, the thickness of the heat sink on the outer side of the coil in the axial direction of the coil is thinner than the thickness of the heat sink between the windings. By thinning the heat sink on the outer side of the coil, which contributes little to cooling of the coil, it is possible to suppress the amount of the heat sink without reducing the cooling performance for the coil.

Description

Technical Field

[0001] The technology disclosed in this specification relates to reactors with cores inserted through coils and methods for manufacturing them. Background Technology

[0002] Japanese Patent Application Publication Nos. 2019-050286 and 2016-092313 disclose reactors that include heat sinks (heat dissipation fins) connected to the side of the coil. The heat sink absorbs heat from the coil. In other words, the heat sink cools the coil. To effectively cool the coil, the heat sink is inserted between adjacent windings of the coil. Summary of the Invention

[0003] This manual provides information on reactors and their manufacturing methods.

[0004] The reactor according to the first aspect of this disclosure includes: a coil with a gap between adjacent windings; a core inserted through the coil; and a heat sink connected to the side of the coil. The heat sink is inserted between adjacent windings of the coil. Furthermore, the thickness of the heat sink on the outer side of the coil in the axial direction of the coil is thinner than the thickness of the heat sink between adjacent windings. By making the heat sink thinner on the outer side of the coil, which contributes little to the cooling of the coil, the amount of heat sink can be suppressed without reducing the cooling performance for the coil.

[0005] In the reactor of the first embodiment described above, the heat sink can be wrapped around the winding in a cross-section cut by the plane passing through the axis of the coil and the heat sink. Because the heat sink is wrapped around the winding, it is difficult to peel off from the winding. Alternatively, the heat sink can be connected to the core. The heat sink can also contribute to the cooling of the core.

[0006] In the reactor of the first embodiment described above, the spacing between adjacent windings widens as they move away from the core on the side where the heat sink of the coil is connected. According to the above embodiment, when the spacing between the windings widens as they move away from the core, the heat sink filling the space between the windings is difficult to peel off.

[0007] The reactor described above may also include a resin cover that covers the coil and the core in a manner that exposes the coil on one side.

[0008] The manufacturing method of the second aspect of this disclosure also provides a method for manufacturing a reactor suitable for which the spacing between adjacent windings widens as it moves away from the core. This manufacturing method includes three steps. In the first step, a coil having a gap between adjacent windings and a core through which the coil is inserted are placed into a mold. In the second step, a force parallel to the axis of the coil is applied to one side of the coil's axis such that one end of the gap is wider than the other end when viewed from the side, and a resin cover is formed to cover the coil and the core so that the coil is exposed on one side. In the third step, a heat sink is formed at the portion of the coil exposed from the resin cover, which contacts the side of the coil and is inserted into the gap.

[0009] In the second method described above, the coil can also be clamped by a pressure pin and a bearing pin, and a force parallel to the axis can be applied by the pressure pin.

[0010] In the second method described above, the resin cover can also be formed by injecting molten resin into the mold cavity and then removing it from the mold.

[0011] In the method of the second embodiment described above, the heat sink can also be formed such that the thickness of the heat sink outside the coil in the direction of the axis is thinner than the thickness of the heat sink in the gap.

[0012] The following "Detailed Description" describes the technology disclosed in this specification and further improvements. Attached Figure Description

[0013] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and wherein:

[0014] Figure 1 This is a top view of the reactor in the first embodiment.

[0015] Figure 2 This is a front view of the reactor in the first embodiment.

[0016] Figure 3 This is a side view of the reactor in the first embodiment.

[0017] Figure 4 It is along Figure 1 A cross-sectional view of line IV-IV.

[0018] Figure 5 This is a cross-sectional view of the reactor in the second embodiment.

[0019] Figure 6 This is a cross-sectional view of the reactor in the third embodiment.

[0020] Figure 7 This is a diagram illustrating the first step in the manufacturing process of a reactor.

[0021] Figure 8 This is a diagram illustrating the second step in the manufacturing process of a reactor.

[0022] Figure 9 This is a diagram illustrating the second step in the manufacturing process of a reactor.

[0023] Figure 10 This diagram illustrates the third step in the manufacturing process of a reactor. Detailed Implementation

[0024] Example 1

[0025] Referring to the accompanying drawings, the reactor 2 of the first embodiment will be described. Figures 1-3 These are top, front, and side views of reactor 2. Core 3 and part of coils 4 and 5 are covered by resin cover 6, but for ease of understanding, resin cover 6 is depicted with virtual lines.

[0026] The reactor 2 comprises a ring-shaped core 3, two coils 4 and 5, a base 7, a resin cover 6, and a heat sink 9. The heat sink 9 is located in... Figures 1-3 It cannot be seen in the sectional view. Figure 4 The diagram shows that core 3 is inserted through two coils 4 and 5. Core 3 extends further outward than coil 4 (coil 5) along the axial direction of coil 4 (coil 5). The two coils 4 and 5 are formed by a single winding 8, electrically forming one coil. The leads of coils 4 and 5 are omitted from the diagram.

[0027] Coils 4 and 5 have a gap between adjacent windings 8. The assembly of core 3 and coils 4 and 5 is fixed to base 7. Spacer 11 is fixed to base 7, and core 3 is fixed to the upper surface of spacer 11. Although not shown in the figure, tabs may also be provided on resin cover 6 to fix the tabs to base 7.

[0028] The resin cover 6, represented by a virtual line, exposes the lower parts of coils 4 and 5 and the lower surface of core 3 while covering the remaining parts of coils 4 and 5 and core 3.

[0029] Figure 4 Show along Figure 1 The cross-section along line IV-IV. Figure 4 In the image, a portion of the cross-section of reactor 2 is omitted. Figure 4 The single-dotted line AL represents the axis of coil 4 (axis AL). Figure 4 In this text, the symbol 8 is omitted for several windings. Additionally, when each winding 8 is shown individually, the symbols 8a and 8b are used. For example... Figure 4As shown, winding 8 is a flat-angled wire with a flat cross-section. In coil 4 (coil 5), the flat-angled winding 8 is wound along the edge. Edge winding means winding in a manner that the width of the flat-angled wire faces the axis AL.

[0030] The heat sink 9 is in contact with the lower surface of the coil 4. Figure 4 This is a cross-section of the reactor 2, cut through the plane passing through the axis AL of coil 4 and the heat sink 9. Although not shown in the figure, the heat sink 9 is also in contact with the lower surface of coil 5. The structural relationship between the heat sink 9 and coil 5 is the same as that between the heat sink 9 and coil 4. Therefore, the following will only describe the relationship between the heat sink 9 and coil 4.

[0031] The heat sink 9 is formed from a soft raw material with high heat resistance and high thermal conductivity. For example, it is formed from silicone rubber. A recess 7a is provided on the base 7, and the heat sink 9 is disposed in the recess 7a. The heat sink 9 is in contact with the side (lower surface) of the coil 4 and is also inserted between adjacent windings 8 (e.g., windings 8a, 8b). The heat sink 9 is in contact with both the coil 4 and the base 7. The base 7 is formed from aluminum, which has high thermal conductivity. When current flows through the coil 4, the coil 4 heats up. The heat from the coil 4 is transferred to the base 7 via the heat sink 9. The heat from the coil 4 is released via the heat sink 9 and the base 7. A water-cooled cooler can also be installed under the base 7.

[0032] The heat sink 9 extends to the outside of the coil in the direction of axis AL. For example... Figure 4 As shown, the thickness T1 of the heat sink 9 on the outer side of the coil in the direction of axis AL is thinner than the thickness T2 of the heat sink 9 between adjacent windings (e.g., windings 8a, 8b). In other words, the surface S1 of the heat sink 9 on the outer side of the coil in the direction of axis AL is farther away from the core 3 than the surface S2 of the heat sink 9 between windings (e.g., windings 8a, 8b).

[0033] The heat sink 9, which fills the space between the windings 8, absorbs heat from the windings on both sides (e.g., windings 8a and 8b). On the other hand, the heat sink 9 on the outer side of the coil in the AL direction is only on one side, and is only connected to the winding 8 (the outermost winding in the AL direction). The heat sink 9 on the outer side of the coil 4 in the AL direction contributes less to coil cooling than the heat sink 9 between adjacent windings 8. By thinning the heat sink 9 in areas where its contribution to coil cooling is small, the amount of heat sink 9 can be suppressed without reducing the cooling performance for the coil 4.

[0034] Example 2

[0035] Figure 5 A cross-section of the reactor 2a of the second embodiment is shown. Figure 5 cross section and Figure 4Corresponding to the cross-section. In reactor 2a, in a cross-section cut by a plane passing through the axis AL of coil 4 and the heat sink 9a, the heat sink 9a surrounds the windings of coil 4 (e.g., windings 8a, 8b). In other words, the heat sinks 9a, located on both sides of the windings in the direction of the axis AL, connect the windings to the core 3. Further, in... Figure 5 In the cross-section, except for the winding 8c located at the end in the direction of axis AL, the heat sink 9a fills the area around the other windings 8. Because the heat sink 9a surrounds the windings 8 (except for the winding 8c at the end), it is difficult to peel off from the windings 8.

[0036] Furthermore, the heat sink 9a is connected to the core 3. Through this connection, the heat sink 9a can also absorb heat from the core 3. Additionally, in the reactor 2a of the second embodiment, the thickness T1 of the heat sink 9a on the outer side of the coil along the axial direction AL is thinner than the thickness T2 of the heat sink 9a between the windings 8.

[0037] 3rd Embodiment

[0038] Figure 6 A cross-section of reactor 2b of the third embodiment is shown. Figure 6 cross section and Figure 4 Corresponding to the cross-section. In reactor 2b, on the side where the heat sink 9 is connected, the spacing between adjacent windings 8 widens as they move away from the core 3. For example, in windings 8a and 8c, the spacing G2 on the side away from the core 3 is wider than the spacing G1 on the side closer to the core 3. The gap between windings 8a and 8b also widens as they move away from the core 3. The same applies to other windings. When the spacing between windings 8 widens as they move away from the core 3, it is difficult to peel off the heat sink 9 filling the space between windings 8. Furthermore, in the gap between at least one pair of windings, it is sufficient for the gap to widen as it moves away from the core 3. In several gaps, the spacing can also be constant. Furthermore, in reactor 2b of the third embodiment, the thickness T1 of the heat sink 9 on the outer side of the coil in the direction of axis AL is also thinner than the thickness T2 of the heat sink 9 between windings 8.

[0039] Next, refer to Figures 7 to 10 This describes the manufacturing method of reactor 12. Reactor 12 includes a linear core 13, a coil 14, a resin cover 16, and a heat sink 19 (see reference). Figure 10 ).

[0040] Process 1

[0041] First, coils 14 with gaps between adjacent windings and cores 13 inserted through coils 14 are placed into mold 20. Figure 7 Mold 20 consists of mold 1 21 and mold 22. Figure 7The diagram shows the assembly of coil 14 and core 13 positioned in the first mold 21. The lower end of coil 14 is covered by the first mold 21. The first mold 21 includes a pressure pin 23 for subsequently pressing coil 14 towards the axis AL (the axis of coil 14). The second mold 22 includes a receiving pin 24 that clamps coil 14 together with the pressure pin 23. Additionally, the second mold 22 includes a piston 25 for accumulating molten resin. The gate 26 of the piston 25 closes before the mold 20 closes.

[0042] Process 2

[0043] While applying a force parallel to the axis AL on one side of the coil 14 such that one end (lower end in the figure) of the gap between the windings when viewed from the side is wider than the other end (upper end in the figure), molten resin is injected into the mold cavity 29 of the mold 20 to form a resin cover 16 covering the coil 14 and the core 13 such that the coil 14 is exposed on one side (lower end in the figure). Figure 8 As shown, a force parallel to the axis AL is applied on the side above the axis AL of the coil 14 using a pressure pin 23 and a bearing pin 24. Figure 8 The white arrow indicates the force applied to coil 14. In other words, coil 14 is clamped in place by pressure pin 23 and bearing pin 24 on the upper side of axis AL. As a result, the winding spacing of coil 14 becomes narrower on the upper side of axis AL. That is, the winding spacing in the lower end of coil 14 is wider than the winding spacing in the upper end of coil 14. In this state, gate 26 is opened, and molten resin is injected from piston 25 into mold cavity 29. The lower end of coil 14 is covered by first mold 21, so it is isolated from the molten resin. As the resin solidifies, the lower side of coil 14 is exposed, forming a resin cover 16 covering the remaining part of coil 14 and core 13. Mold 20 is opened, and subassembly 12a (refer to) with resin cover 16 formed is removed. Figure 9 ).

[0044] Process 3

[0045] Heat sink 19 is installed on the exposed portion of coil 14. Figure 10 Heat sink 19 is inserted between adjacent windings of coil 14, such that the thickness T1 of heat sink 19 on the outer side of the coil in the direction of axis AL is thinner than the thickness T2 of heat sink 19 between windings. Although not shown in the figure, finally, reactor 12 is mounted to the base. Thus, reactor 12 is completed.

[0046] In the reactor 12 manufactured by the above-described method, in the portion exposed from the resin cover 16, the gap between adjacent windings of the coil 14 increases as it moves away from the core 13. A heat sink 19 fills the gradually widening gap. The heat sink 19 is difficult to peel off from the windings.

[0047] A heat sink 19 is installed on the exposed portion of the coil 14. Regarding the heat sink 19, the thickness T1 of the outer side of the coil along the axial direction AL is thinner than the thickness T2 between the windings. Therefore, the cooling performance of the coil 14 is not affected, and the amount of heat sink 19 used is reduced.

[0048] exist Figures 7-9 In this design, only one pressure pin 23 is depicted on one side of the axis AL of the coil 14. Alternatively, multiple pins may be used on one side of the axis AL to press the coil 14 in the axial direction. Or, a single, wide pin may be used on one side of the axis AL to press the coil 14 in the axial direction.

[0049] The outermost winding along axis AL is preferably tilted at more than 1 degree relative to the central winding.

[0050] The mold 20 used in the manufacturing method of the embodiment can be achieved simply by adding a pressure pin 23 and a bearing pin 24 to a conventional mold. The apparatus used in the manufacturing method of the embodiment can be implemented at low cost.

[0051] Notes relating to the techniques described in the embodiments are provided below. The reactor of the embodiments has a ring-shaped core and two coils. The techniques disclosed in this specification can also be applied to reactors having a straight core and one coil.

[0052] Heat sinks can also be sheet-like. They can also be potting materials that are initially gel-like and cure upon contact with air (or heating).

[0053] The specific examples of the present invention have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples described above. The technical elements described in this specification or drawings are technically useful individually or in various combinations, and are not limited to the combinations described in the claims at the time of application. Furthermore, the technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically practical.

Claims

1. A reactor, characterized in that, include: A coil has gaps between adjacent windings; Core, inserted through the coil; as well as A heat sink is connected to the side of the coil. The heat sink is inserted into the gap between adjacent windings of the coil, and the thickness of the heat sink on the outer side of the coil in the axial direction is thinner than the thickness of the heat sink between adjacent windings. On the side of the coil where the heat sink is connected, the spacing between adjacent windings widens as they move away from the core.

2. The reactor according to claim 1, characterized in that, In a cross-section cut by the axis of the coil and the plane of the heat sink, the heat sink surrounds the winding.

3. The reactor according to claim 2, characterized in that, The heat sink is connected to the core.

4. The reactor according to any one of claims 1 to 3, characterized in that, It also includes a resin cover that covers the coil and the core in a manner that exposes the coil on one side.

5. A method for manufacturing a reactor, characterized in that, include: A coil with a gap between adjacent windings and a core inserted through the coil are set into a mold; While applying a force in a direction parallel to the axis of the coil on one side of the coil axis such that one end of the gap is wider than the other end when the coil is viewed from the side, a resin cover is formed to cover the coil and the core in such a way that the coil is exposed on one side, so that in the part where the coil is exposed from the resin cover, the gap between adjacent windings of the coil increases as it moves away from the core; as well as A heat dissipation element is formed at the portion of the coil that protrudes from the resin cover, and is connected to the side of the coil and inserted into the gap.

6. The method according to claim 5, characterized in that, The coil is clamped by a pressure pin and a bearing pin, and a force parallel to the axis is applied through the pressure pin.

7. The method according to claim 5 or 6, characterized in that, The resin cover is formed by injecting molten resin into the mold cavity, and then the resin cover is removed from the mold.

8. The method according to claim 5 or 6, characterized in that, In the formation of the heat sink, the heat sink is formed such that the thickness of the heat sink outside the coil in the direction of the axis is thinner than the thickness of the heat sink in the gap.

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