JP5245939B2 - Reactor - Google Patents

Description

  The present invention relates to a reactor having excellent heat dissipation and low noise.

Conventionally, a reactor used for an inverter for a vehicle or the like is known (see Patent Document 1 below). In FIG. 16, sectional drawing of the conventional reactor 90 is shown. As shown in the figure, the reactor 90 includes a core 91 made of a magnetic powder mixed resin in which a magnetic powder is dispersed in an insulating resin, a coil 92, and a columnar member 95 for heat dissipation.
As shown in the figure, both end portions of the columnar member 95 have a skirt shape with a larger diameter as the distance from the center increases. The reason for this shape is to increase the contact area with the case 94 and efficiently transfer the heat generated by the coil 92 to the case 94.

  As shown in FIG. 17, a gap 96 is formed between the bottom portion 95 a of the columnar member 95 and the core 91. The gap 96 is formed in this way for the following reason. That is, when the reactor 90 is manufactured, first, a mold (not shown) for molding is separately prepared, the columnar member 95 and the coil 92 are arranged in this mold, a liquid core material is poured, solidified, and cooled. Thus, a member in which the columnar member 95, the coil 92, and the core 91 are integrated is formed. In this way, the volume of the core 91 contracts during cooling, and a gap 96 is formed between the skirt 95a and the core 91.

JP 2008-198981 A

  However, since an alternating current flows through the coil 92, there is a problem that the coil 92 vibrates due to a force (ampere force) acting between the currents. Since the conventional reactor 90 has the gap 96, the surface 91a of the core 91 comes into contact with the skirt 95a due to the vibration of the coil 92, and noise is likely to occur.

  On the other hand, since the reactor 90 is used for the inverter for vehicles, a large current flows. Therefore, the vibration amplitude of the coil 92 becomes particularly large, and noise tends to increase. Moreover, since it is for vehicles, it is desired to reduce noise as much as possible so as not to give a passenger discomfort.

  In addition, the temperature of the reactor rises due to current while the vehicle is running, and cools when not in use, so the temperature difference is large. As shown in FIG. 18, since the thermal expansion coefficients of the core 91, the columnar member 95, and the adhesive layer 93 are different from each other, when heating and cooling are repeated, a force is applied in the direction of the arrow in the figure, and the gap 96 gradually expands. There is a problem of going.

  In order to reduce noise, the columnar member 95 may be removed, but if this is eliminated, the cooling efficiency of the coil 92 and the core 91 will not increase. Therefore, a reactor 90 that can efficiently cool the coil 92 and the core 91 and reduce noise is desired.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a reactor capable of efficiently cooling a coil and a core and reducing noise.

The present invention includes a core made of a magnetic powder mixed resin in which a magnetic powder is dispersed in an insulating resin,
A coil embedded in the core and generating magnetic flux when energized;
A columnar member located inside the coil and formed in a columnar shape facing the axial direction of the coil, and embedded in the core in a state where both axial end surfaces are exposed from the outer surface of the core,
The columnar member is formed with an enlarged diameter portion having an outer diameter larger than that of the central portion in the axial direction at at least one end portion of the both end portions, and the outer diameter of the enlarged diameter portion increases toward the outer side in the axial direction. A taper portion that gradually increases, and a chamfered portion whose outer peripheral surface is chamfered so as to be closer to the axial direction than the extending direction of the surface of the taper portion located outside the taper portion in the axial direction;
The contact position between the outer surface of the core and the columnar member is located on the chamfered portion ,
The outer surface of the core in the peripheral region of the chamfered portion has a shape that is curved toward the outer side in the axial direction as it approaches the chamfered portion,
The core is formed by curing the liquid magnetic powder mixed resin,
The length of the chamfered portion in the axial direction is in a reactor characterized by being longer than the contraction length of the core in the axial direction when the magnetic powder mixed resin is cured .

According to the said invention, the enlarged diameter part is formed in the columnar member. The enlarged diameter portion is composed of the tapered portion and the chamfered portion, and the contact position between the outer surface of the core and the columnar member is located on the chamfered portion.
If it does in this way, the outer surface of a core will not be applied to the surface of a taper part, but will be applied to the outer peripheral surface of a chamfering part. The outer peripheral surface of the chamfered portion has a shape close to a cylinder with the axis as the central axis, as compared with the outer peripheral surface of the tapered portion.
As described above, when a core is manufactured by pouring a liquid core material into a molding die and cooling and solidifying, the volume of the core is reduced during cooling. However, with the above configuration, even when such a manufacturing method is used, the outer peripheral surface of the chamfered portion has a shape similar to a cylinder, so even if the core contracts in the axial direction, it is between the core and the columnar member. It becomes difficult to create a gap.
Therefore, even when the core vibrates due to the vibration of the coil, the surface 91a of the core 91 does not hit the columnar member 95 in the gap 96 (see FIG. 17) as in the prior art, and noise is less likely to occur.

  On the other hand, in the present invention, heat generated from the core or coil is transmitted to the outside through the columnar member, so that the core or the like can be efficiently cooled.

  As described above, according to the present invention, it is possible to provide a reactor capable of efficiently cooling a coil and a core and reducing noise.

FIG. 3 is an exploded perspective view of the reactor in the first embodiment. Sectional drawing of the reactor in Example 1. FIG. 2 is an enlarged view of the main part of FIG. The manufacturing process explanatory drawing of the reactor in Example 1. FIG. The figure following FIG. The figure following FIG. The figure following FIG. The figure following FIG. The figure following FIG. The circuit diagram using the reactor in Example 1. FIG. Explanatory drawing of the electric current which flows into a reactor in Example 1. FIG. The figure for demonstrating the temperature change of the reactor in Example 1. FIG. Sectional drawing of the reactor in Example 2. FIG. The principal part expanded sectional view of the reactor in Example 3. FIG. The principal part expanded sectional view of the reactor in a comparative example. Sectional drawing of the reactor in a prior art example. The principal part enlarged view of the reactor in a prior art example. The principal part enlarged view of the reactor in a prior art example.

A preferred embodiment of the present invention described above will be described.
In the present invention, in the peripheral region of the chamfered portion, the outer surface of the core, the system is in the curved shape toward the axially outward closer to the chamfer.
Therefore , it becomes more difficult to create a gap between the core and the columnar member. For this reason, noise due to the vibration of the coil is unlikely to occur.
In addition, when using the said manufacturing method (a core material is poured into a type | mold, it solidifies, and it cools), it can be made into the said shape naturally with the surface tension which acts on a core material, even if it does not perform a process in particular.

In addition, a storage case for storing the core, the columnar member, and the coil is provided, and an adhesive layer for bonding the core is interposed between an outer surface of the core and an inner surface of the storage case. (Claim 2 ).
In the conventional reactor, as shown in FIG. 18, the coefficient of thermal expansion of the core 91, the columnar member 95, and the adhesive layer 93 is different, so that the gap 96 gradually expands while heating and cooling are repeated. was there. That is, when an adhesive layer is present, noise tends to increase gradually.
However, if the present invention is used, there is no gap between the core and the columnar member, so that the above-described problem hardly occurs. Therefore, when the present invention is applied in a state where the adhesive layer exists, the effect is particularly great.

Moreover, it is preferable that the end surface of the said columnar member is contacting the bottom face of the said storage case (Claim 3 ).
In this way, the heat generated from the coil and the core passes through the columnar member and is further transmitted to the storage case, so that the cooling efficiency can be particularly increased.

Moreover, it is preferable that the said enlarged diameter part is formed in the both ends of the said columnar member (Claim 4 ).
If it does in this way, since two diameter expansion parts are formed in the columnar member, heat dissipation efficiency can be made especially high. For example, the storage case is covered with a metal plate. Then, if one enlarged portion of the columnar member is in contact with the bottom surface of the storage case and the other enlarged portion is in contact with the lid, the heat generated from the coil or the like is applied to both the storage case and the lid. Since it is transmitted, the heat dissipation efficiency is particularly high.

Example 1
A reactor according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an exploded perspective view of the reactor 1 of this example, and FIG. 2 is a sectional view thereof. As shown in FIGS. 1 and 2, the reactor 1 of this example includes a core 4 made of a magnetic powder mixed resin in which a magnetic powder is dispersed in an insulating resin. A coil 2 that generates magnetic flux when energized is embedded in the core 4. And it is located in the inside of the coil 2 and is formed in a columnar shape facing the axial direction of the coil 2, and is a columnar shape embedded in the core 4 with both axial end surfaces 51 and 52 exposed from the core outer surface 40. A member 3 is provided.
The columnar member 3 is formed with an enlarged diameter portion 5 having an outer diameter larger than that of the axial central portion 30 at at least one end portion of the both end portions, and the enlarged diameter portion 5 has an outer diameter toward the outer side in the axial direction. And a chamfered portion 5b in which the outer peripheral surface 50 is chamfered so as to be closer to the axial direction than the extending direction of the tapered surface 500 and located outside the tapered portion 5a in the axial direction. ing.
As shown in FIG. 3, the contact position 41 between the outer surface 40 of the core 4 and the columnar member 3 is located on the chamfered portion 5b.
Details will be described below.

  The core 4 of this example uses iron powder as the magnetic powder, and uses a thermosetting resin such as an epoxy resin as the insulating resin. The coil is formed by winding a copper wire. The columnar member 3 and the storage case 7 are made of aluminum. The storage case 7 has a convex portion 13 on the bottom surface, and the columnar member 3 and the storage case 7 are integrated by screwing a bolt 10 to the convex portion 13 and a female screw portion formed on the columnar member 3. ing.

Further, as shown in FIG. 3, the outer surface 40 of the core 4 has a curved shape such that the peripheral area of the chamfered portion 5b is directed outward in the axial direction as the chamfered portion 5b is approached.
By using the manufacturing method described later, such a shape can be naturally formed without any particular processing.

Moreover, the reactor 1 of this example is provided with the storage case 7 which accommodates the core 4, the columnar member 3, and the coil 2, as shown in FIG. 2, the outer surface 40 of the core 4, the inner surface 70 of the storage case 7, An adhesive layer 6 for adhering the core 4 is interposed therebetween.
As the adhesive layer 6, for example, a urethane resin can be suitably used. Since the urethane resin is soft, it also has an effect of absorbing the vibration of the coil 2.

In this example, as shown in FIG. 2, the end surface 51 of the columnar member 3 is in contact with the bottom surface of the storage case 7.
Furthermore, in this example, as shown in FIG. 2, the enlarged diameter portions 5 are formed at both ends of the columnar member 3.

Next, the manufacturing method of the reactor 1 of this example is demonstrated using FIGS.
First, as shown in FIG. 4, a molding die 8 (different from the storage case 7) is prepared, and the columnar member 3 and the coil 2 are put therein.
Thereafter, as shown in FIG. 5, the liquid core material 4 ′ is poured into the mold 8. The core material 4 ′ is obtained by dispersing iron powder in a thermosetting resin such as an epoxy resin, and the thermosetting resin is not cured at the stage of FIG.

As shown in FIG. 6, when a predetermined amount of the core material 4 ′ is added and then heat treatment is performed, the thermosetting resin is cured. Thereby, the core 4, the columnar member 3, and the coil 2 are united.
Thereafter, when the core 4 is cooled, the volume of the core 4 is reduced as shown in FIG. 7, and a gap 400 is formed between the mold 8 and the core 4.
As a result, as shown in FIG. 8, the member 14 in which the columnar member 3, the coil 2, and the core 4 are integrated can be easily removed from the mold 8.

  The axial direction length of the chamfered portion 5 b is set to be longer than the contraction amount of the core 4. Therefore, after the volume of the core 4 contracts, the outer surface 40 (see FIG. 3) of the core 4 is applied to the outer peripheral surface 50 of the chamfered portion 5b and does not cover the surface 500 of the tapered portion 5a. Further, due to the surface tension of the core 4, the surface 40 of the core 4 has a curved shape as shown in FIG. 3. Therefore, unlike the conventional reactor (see FIG. 17), the problem that a gap 96 is formed between the core 91 and the columnar member 95a is unlikely to occur.

Thereafter, as shown in FIG. 9, a small amount of the liquid adhesive 6 is put in the storage case 7, and the member 14 is stored therein. Thus, the adhesive 6 enters the gap between the member 14 and the storage case 7 (see FIG. 2), and the member 14 and the storage case 7 can be bonded.
Further, after the member 14 is stored, the member 14 is fixed to the storage case 7 using the bolt 10.

Next, a circuit in which the reactor 1 is used will be described. FIG. 10 is an example of a power conversion device 800 mounted on a vehicle. As illustrated, the power conversion device 800 includes an inverter 80, a converter 81, and a DC power source 84. As shown in the figure, the inverter 80 includes a plurality of semiconductor modules 85. Each semiconductor module 85 includes an IGBT element 85a and a flywheel diode 85b.
The voltage of DC power supply 84 is boosted by converter 81 and the boosted voltage is input to inverter 80. And it converts into alternating current power in the inverter 80, drives the three-phase alternating current motor 82 using the alternating current power, and makes a vehicle drive | work.
On the other hand, the converter 81 includes the reactor 1 and the semiconductor module 86 of this example. By switching the IGBT element 86a of the semiconductor module 86, an alternating current shown in FIG. As a result, the voltage of the DC power supply 84 is boosted.

Next, the function and effect of this example will be described.
As shown in FIGS. 2 and 3, in the reactor 1 of this example, the diameter-enlarged portion 5 is formed in the columnar member 3. The enlarged diameter portion 5 includes a tapered portion 5a and a chamfered portion 5b, and the contact position between the outer surface of the core 4 and the columnar member 3 is located on the chamfered portion 5b.
If it does in this way, the outer surface 40 of the core 4 will not cover the surface 500 of the taper part 5a but the outer peripheral surface 50 of the chamfered part 5b. The outer peripheral surface 50 of the chamfered portion 5b has a shape close to a cylinder centering on the axis, as compared with the outer peripheral surface of the tapered portion 5a.
As described above, when the core is manufactured by pouring the liquid core material 4 ′ into the mold 8 and cooling and solidifying, the volume of the core 4 is reduced during cooling. However, with the above configuration, even when such a manufacturing method is used, the outer peripheral surface 50 of the chamfered portion 5b has a shape close to a cylinder. Therefore, even if the core 4 contracts in the axial direction, the core 4 and the columnar member 3 is difficult to create a gap.
Therefore, even when the core vibrates due to the vibration of the coil, the surface 91a of the core 91 does not hit the columnar member 95 in the gap 96 (see FIG. 17) as in the prior art, and noise is less likely to occur.

Further, as shown in FIG. 3, the outer surface 40 of the core 4 in the peripheral region of the chamfered portion 5b has a shape curved toward the outer side in the axial direction as it approaches the chamfered portion 5b.
If it does in this way, it will become difficult to make a clearance gap between the core 4 and the columnar member 3 further. Therefore, noise due to vibration of the coil 2 is unlikely to occur.
In addition, when using the said manufacturing method (pour core material 4 'into the type | mold 8 and solidify and cool), if the viscosity of core material 4' and the angle of the chamfering part 5b are adjusted, it will not need to process especially. The above shape can be naturally achieved by the surface tension acting on the core material.

Further, as shown in FIG. 2, in this example, a storage case 7 that stores the core 4, the columnar member 3, and the coil 2 is provided, and between the outer surface 40 of the core 4 and the inner surface 70 of the storage case 7. In addition, an adhesive layer 6 for adhering the core 4 is interposed.
In the conventional reactor 1, as shown in FIG. 18, since the thermal expansion coefficients of the core 91, the columnar member 95, and the adhesive layer 93 are different, the gap 96 gradually expands while heating and cooling are repeated. There was a problem. That is, when an adhesive layer is present, noise tends to increase gradually.
However, if the present invention is used, there is no gap between the core 4 and the columnar member 3, so that the above-described problem is hardly caused. Therefore, when the present invention is applied in the state where the adhesive layer 6 exists, the effect is particularly great.

As shown in FIG. 2, in this example, the end surface of the columnar member 3 is in contact with the bottom surface of the storage case 7.
In this way, the heat generated from the coil 2 and the core 4 passes through the columnar member 3 and is further transmitted to the storage case 7, so that the cooling efficiency can be particularly increased.

Moreover, the reactor 1 of this example is used for the power converter device 800 of a vehicle as shown in FIG. Since a large current flows through the power conversion device 800 of the vehicle, the amplitude of vibration of the coil 2 is large and noise tends to increase. In addition, there is a particularly great demand for reducing noise in order not to be heard by passengers.
Furthermore, as shown in FIG. 13, when the vehicle is driven, the temperature of the reactor increases, and when the vehicle is not driven, the temperature decreases. As described above, since the temperature difference is large, the conventional reactor is likely to have a problem that the gap gradually expands and noise increases as described above, but in the case of the present invention, the gap does not occur. Problems are less likely to occur.
Thus, the reactor of this example is particularly effective when used in a vehicle power converter.

  As described above, according to this example, it is possible to provide the reactor 1 that can efficiently cool the coil 2 and the core 4 and can reduce noise.

(Example 2)
In this example, as shown in FIG. 13, the reactor 1 is provided with a lid 71. The lid 71 is made of a metal plate and is fixed to the storage case 7 by screws 15. Further, the columnar member 3 has an enlarged diameter portion 5 formed at both ends. One enlarged diameter portion 5 x is in contact with the bottom surface of the storage case 7, and the other enlarged diameter portion 5 y is in contact with the lid 71.
In addition, the configuration is the same as that of the first embodiment.

  The effect of this example will be described. In this example, one enlarged diameter portion 5 x of the columnar member 3 contacts the bottom surface of the storage case 7, and the other enlarged diameter portion 5 y contacts the lid 71. Therefore, heat generated from the coil 2 and the core 4 is transmitted to both the storage case 7 and the lid 71. Thereby, heat dissipation efficiency can be improved.

(Example 3)
In this example, the shape of the chamfered portion 5b is changed. As shown in FIG. 14, the chamfered portion 5b of this example is slightly tapered. In this way, the contact area between the chamfered portion 5b and the storage case 7 can be slightly increased as compared with the first embodiment. Therefore, the heat dissipation efficiency increases.
On the other hand, when the chamfered portion 5b is at an angle close to the tapered portion 5a, a gap 96 is formed as shown in the comparative example of FIG. For this reason, it is preferable that the chamfered portion 5b does not have an angle.
The angle θ formed between the outer peripheral surface 50 of the chamfered portion 5b and the end surface 51 is preferably 60 ° to 90 °. If θ is within this range, it is difficult to form a gap between the core 4 and the chamfered portion 5b. The angle θ is more preferably 75 ° to 90 °, and most preferably 90 ° as in the first embodiment.

DESCRIPTION OF SYMBOLS 1 Reactor 2 Coil 3 Columnar member 30 Axis direction center part 4 Core 5 Expanded part 5a Taper part 5b Chamfering part 50 (Chamfering part) Outer peripheral surface 51, 52 (Chamfering part) End face 6 Adhesive layer 7 Storage case 70 (Storage) Inner surface of the case

Claims (4)

A core made of a magnetic powder mixed resin in which magnetic powder is dispersed in an insulating resin;
A coil embedded in the core and generating magnetic flux when energized;
A columnar member located inside the coil and formed in a columnar shape facing the axial direction of the coil, and embedded in the core in a state where both axial end surfaces are exposed from the outer surface of the core,
The columnar member is formed with an enlarged diameter portion having an outer diameter larger than that of the central portion in the axial direction at at least one end portion of the both end portions, and the outer diameter of the enlarged diameter portion increases toward the outer side in the axial direction. A taper portion that gradually increases, and a chamfered portion whose outer peripheral surface is chamfered so as to be closer to the axial direction than the extending direction of the surface of the taper portion located outside the taper portion in the axial direction;
The contact position between the outer surface of the core and the columnar member is located on the chamfered portion ,
The outer surface of the core in the peripheral region of the chamfered portion has a shape that is curved toward the outer side in the axial direction as it approaches the chamfered portion,
The core is formed by curing the liquid magnetic powder mixed resin,
The length of the chamfered portion in the axial direction is longer than the contraction length of the core in the axial direction when the magnetic powder mixed resin is cured . Oite to claim 1, and the core, and the columnar member, comprising a housing case for housing and the coil, and the outer surface of the core, between the inner surface of the housing case, the adhesive for bonding the core Reactor characterized by intervening layers. The reactor according to claim 2, wherein an end surface of the columnar member is in contact with a bottom surface of the storage case. The reactor according to any one of claims 1 to 3 , wherein the enlarged-diameter portion is formed at both ends of the columnar member.

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