JP2014041941A - Mold type transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that while a mold case (case body) is formed by storing a primary coil and a secondary coil, and then fitting a first case and a second case, and the case body is turned upside down so as to be filled with insulating resin such as epoxy resin from an injection port as a leg part, a case fitting force in the neighborhood of the injection port tends to be weakened, and the case body is opened as a result possibly causing the insulating resin to leak from the opened portion.SOLUTION: The mold type transformer comprises: a case body formed by fitting a first case and a second case; a case body support leg part integrally formed with the first case and the second case of the case body, and formed with an injection port from which insulating resin to be filled in the case body is injected; and a cover body with which the injection port is closed. The cover body is formed with a cover body cylindrical insertion part to be inserted from the injection port into the case body support leg part.

Description

  The present invention relates to a molded transformer in which a primary coil and a secondary coil are housed in a mold case, filled with an insulating resin, and an iron core is combined.

  A conventional mold-type transformer includes a primary coil, a secondary coil, a mold case for storing these, an epoxy resin filled in the mold case, an iron core, and mounting legs. In the completed state, the epoxy resin is cured and the primary coil, the secondary coil, and the mold case are integrated. (For example, see Patent Document 1)

JP 2011-29547 A

The conventional mold type transformer is configured as described above, but the mold case (case body) is divided into a first case and a second case, and accommodates a primary coil and a secondary coil. Later, the first case and the second case are fitted together. After that, it is turned upside down and filled with insulating resin such as epoxy resin from the injection port which is also the leg, but the case fitting force near the injection port tends to be weak, so that the case body is released as a result There may be a problem that the insulating resin leaks from the opened portion due to the open state.
The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a mold type transformer in which insulating resin does not leak.

  A mold type transformer according to the present invention includes a case main body formed by fitting a first case and a second case, the first main body and the second case of the case main body, and the case main body. A case body support leg portion formed with an injection port for injecting an insulating resin filled therein, and a lid body for closing the injection port, and the lid body is fitted into the case body support leg portion from the injection port. A lid tubular insertion portion to be inserted is formed.

  According to the mold type transformer of the present invention, the insulating resin is added by adding a structure in which the insulating resin enters between the case main body and the lid body against the stress applied from the insulating resin in the dividing direction of the case main body after the insulating resin is injected. The resin plays the same role as the adhesive, and the two cases (the first case and the second case) are fixed to strengthen the fitting force. Thereby, the effect which suppresses that a case main body support leg part isolate | separates especially in the vicinity of the injection hole of insulating resin is acquired, and the leakage of insulating resin can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view which shows the mold type transformer in the actual form 1 of this invention, (a) is a front view, (b) is a side view. It is a side view which shows the state which divided | segmented the case main body of the mold type transformer in the form 1 of the actual condition of this invention. It is the cover body which plugs up the injection port of the mold type transformer in the actual form 1 of this invention, (a) is a plan view, (b) is a bottom view, and (c) is a side view. It is the perspective view of the mold type transformer in the form 1 of the actual condition of this invention, and is the figure which showed the process of plugging an injection port with the cover body of FIG. FIG. 5 is a perspective view showing the vicinity of an injection port in a state where a lid is incorporated in a case body support leg in the mold-type transformer according to the first embodiment of the present invention. It is the bottom view of the mold type transformer in the form 1 of the actual condition of this invention, and is the figure which removed and showed the iron core and the attachment board | substrate. FIG. 7 is a side cross-sectional view of the mold type transformer taken along the line AA in FIG. 6 in the direction of the arrow, and is a view before the lid is incorporated into the case body. It is a sectional side view of the mold type transformer which looked at the AA line of Drawing 6 in the direction of an arrow, and is a figure showing the state before hardening shrinkage of insulating resin. It is sectional drawing of the mold type transformer which looked at the BB line of FIG. 8 in the arrow direction. It is sectional drawing of the mold type transformer seen in the arrow direction of the AA line of FIG. 6, and is a figure which shows the state after hardening shrinkage | contraction of insulating resin. It is a bottom view of the mold type transformer in Embodiment 2 of this invention, and is a figure which removed an iron core, a mounting board, a primary coil, a secondary coil, a cover body, etc., and showed the internal structure of a case main body support leg especially. In the mold type | mold transformer in Embodiment 2 of this invention, it is explanatory drawing which shows a cover body and injection port vicinity, (a) is a cross-sectional view after cover body mounting | wearing, (b). The sectional view of the mold type transformer according to the third embodiment of the present invention is shown, and is a sectional view corresponding to the sectional view of the AA line in FIG. FIG. The sectional view of the mold type transformer in Embodiment 3 of this invention is shown, and it is sectional drawing equivalent to sectional drawing which looked at the AA line of FIG. 6 in the arrow direction, and description in the case where hardening shrinkage | contraction of insulation resin is large FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, the same code | symbol shows the same or an equivalent part between each figure.

Embodiment 1 FIG.
FIGS. 1-10 shows the mold type transformer in Embodiment 1, The mold type transformer 100 shown in these figures is comprised with the following member. That is, the mold transformer 100 is housed in the case body 30 formed by fitting the first case 30L and the second case 30R, which are thermoplastic resin molded products, for example, and is wound into a concentric cylindrical shape. The primary coil 1 that is turned and connected to the line to be measured, the secondary coil 2 that is also housed in the case body 30 and connected to the measuring instrument, and the first case 30L and the second case 30R are molded integrally. A case body support leg 31 (31L, 31R) in which an insulating resin injection port (hereinafter referred to as “injection port”) 32 for injecting a thermosetting insulating resin to be described later is formed, a lid 34 for closing the injection port 32, and an injection port 32, which is filled around the coils 1 and 2 and is cured at a high temperature, and is composed of, for example, a thermosetting insulating resin (hereinafter referred to as “insulating resin”) 4 such as epoxy.

  The insulating resin 4 is shown in FIG. 7 (process for injecting the insulating resin 4), FIG. 8 (process before the insulating resin 4 is cured by closing the injection port 32 with the lid 34), and FIG. 10 (after the insulating resin 4 is cured). As shown in FIG. 5), the primary coil 1, the primary terminal 1a, the secondary coil 2, and the secondary coil are filled by filling the periphery of the coils 1 and 2 from the injection port 32 and curing the insulating resin 4 at a high temperature. The terminal 2a and the case body 30 are integrally formed. The primary coil 1 is fixed to the primary terminal 1a by rivet caulking or welding.

The lid 34 that closes the inlet 32 has a lid cylindrical fitting insertion portion 34a that is fitted into the case main body support leg portion 31 (31L, 31R) from the injection port 32. As shown, the buried metal 35 is incorporated.
Further, as will be described later, vertical recesses 34b respectively facing the inner wall portions 31b of the case body support leg portions 31 are provided on the outer periphery of the lid cylindrical insertion portion 34a. Is filled with an insulating resin 4 as an adhesive (see FIG. 9).

  A through-hole 33 is disposed substantially at the center of the case body 30, and the iron core 5 is fitted into the through-hole 22 and is fixed to the case body 30 by a mounting bracket. Further, the mounting substrate 6 is fixed by screwing the mounting substrate mounting screw 36 into the screw hole 35 a provided in the buried metal 35, thereby completing the mold type transformer 100.

When the primary current is supplied to the primary coil 1 via the primary terminal 1a, the molded transformer 100 configured as described above generates a magnetic flux in the iron core 5, and based on this magnetic flux, the secondary coil 2 has a secondary current. A secondary current is generated at the secondary terminal 2a.
The molded transformer 100 is used with a connection conductor connected to the connection hole 1a3 of the primary terminal 1a.

Next, the lid 34 will be described in detail with reference to FIGS. 3, 4, 5, 8, and 9.
3 is an explanatory view showing the lid 34, FIG. 4 is a perspective view showing a process of closing the inlet 32 with the lid 34, and FIG. 5 is an inlet in a state where the lid 34 is incorporated in the case body support leg 31. FIG. 9 is a cross-sectional view taken along line B-B in FIG. 8 in the direction of the arrow.

  As shown in FIG. 8, the lid 34 is assembled so as to close the injection port 32 with the buried metal 35 embedded after the case body 30 is filled with the insulating resin 4. At this time, the insulating resin 4 enters between the inner wall of the case body support leg 31 and the outer periphery of the lid cylindrical fitting insertion portion 34a, and the insulating resin 4 is also lowered into the recess 34b (groove) as shown in FIG. It is filled from (arrow) and functions as an adhesive.

  The vicinity of the injection port 32 is a portion where the fitting force between the first case 30L and the second case 30R is likely to be weak. For example, when the fitting force becomes weak, a gap S may be generated between the cases as shown in FIG. 5, and the filled insulating resin 4 may leak to the outside.

  However, the lid 34 is configured as an integral part as described above, and the insulating resin 4 plays a role of an adhesive, so the lid 34 and the first case 30L, and the lid 34 and the second case 30R. Are fixedly held at positions before the opening between the cases (the first case 30L and the second case 30R), and the occurrence of the gap S between the cases is suppressed to prevent the insulating resin 4 from leaking.

  According to the first embodiment, the insulating resin 4 is allowed to enter between the first case 30L and the second case 30R and the lid 34 which is an integral part, and the insulating resin 4 serves as an adhesive. By fixing, the positions of the first case 30L and the second case 30R are fixed in a state before the case main body 30 is opened, and thereby, the fitting force between the cases is enhanced and the generation of the gap S is suppressed. The leakage of the resin 4 can be prevented.

Embodiment 2. FIG.
In Embodiment 1, it was set as the structure which increases the fitting force between cases by making the insulating resin 4 play the role of an adhesive agent, suppresses generation | occurrence | production of the clearance gap S, and prevents the leakage of the insulating resin 4. FIG.
In the second embodiment, a structure that can be expected to be effective in combination with the first embodiment is added to the case main body 30, that is, the case main body support legs 31, so that the generation of the gap S in the case main body 30 is suppressed, and the insulating resin 4 This is to prevent leakage.

Hereinafter, the mold type transformer according to the second embodiment will be described with reference to FIGS. 11 and 12. In addition, since the structure except having provided the convex part 31a in the inner wall surface of the case main body support leg part 31 is the same as Embodiment 1, description of the same part is abbreviate | omitted.

That is, in the second embodiment, the convex portion 31 a is added to the inner wall surface of the case body support leg portion 31. The positional relationship of the convex portion 31a is a relative position that fits into the concave portion 34b of the lid body 34 when the lid body 34 is attached to the inlet 32 of the case body support leg portion 31.
FIG. 12 shows this state, in which the case body 30 is fixed and held in a state immediately after the first case 30L and the second case 30R are fitted by fitting the convex portion 31a and the concave portion 34b. is there.
According to the second embodiment, the generation of the gap S in the case body 30 can be suppressed more than in the first embodiment, and as a result, the leakage of the insulating resin 4 can be prevented.

  Further, the cylindrical portion of the lid cylindrical fitting insertion portion 34a is designed to enhance the strength by increasing the thickness of the cylindrical portion including the bottom of the concave portion 34b. The stress applied to the case body 30 is relaxed by incorporating the gold 35.

Embodiment 3 FIG.
In the first embodiment, since a thermoplastic resin is used for the insulating resin 4 to be filled, a cavity 40 is generated inside the case main body 30 as shown in FIG. However, there is a problem that the case strength decreases.
In the second embodiment, the shape of the buried metal 35 and the lid 34 that join the case main body 30 and the mounting substrate 6 is reinforced to enhance the strength. However, in this third embodiment, the buried metal 35 is further added. By reinforcing, the strength is enhanced and leakage of the insulating resin 4 is prevented.

  FIG. 13 shows a mold-type transformer according to Embodiment 3 of the present invention, and is an explanatory view when the curing shrinkage of the insulating resin is small and the generation of the cavity 40 is small. FIG. 14 shows the generation of the cavity 40 with a large curing shrinkage of the insulating resin. It is explanatory drawing when is large. Since the configuration other than the buried metal 35 is the same as that of the first embodiment, the description of the same part is omitted.

The buried metal 35 of the third embodiment shown in FIG. 13 and FIG. 14 is extended in length compared to the buried metal 35 of the first embodiment, and is an extended portion that is buried in the insulating resin 4. A lid body retaining recess 35b is formed, and a buried head portion 35c is provided at the most distal end portion.
As described above, the cover 35 is provided with the recess 35b for preventing the cover body from being removed from the extended portion of the buried metal 35, thereby making it difficult for the buried metal 35 to come out of the insulating resin 4. Since the amount embedded in the resin 4 also increases, the embedded volume fraction and the interface of the insulating resin 4 rise, and this can be expected to suppress the increase in the cavity 40.

In the molded transformer of FIGS. 13 and 14, the phenomenon that the size of the cavity 40 is different is caused by the amount of the insulating resin 4 filled in the case body 30 depending on the sizes of the primary coil 1 and the secondary coil 2. The cavity 40 does not become a constant size even if the same amount of the insulating resin 4 is injected.
Hereinafter, the size of the cavity 40 is expressed as “small” when the interface of the insulating resin 4 is above the lid cylindrical insertion portion 34a, and the interface is the lower side of the lid cylindrical insertion portion 34a, that is, the lid. The case where the body cylindrical insertion part 34a is not buried in the insulating resin 4 is expressed as “large”.

  When the cavity 40 is small (FIG. 13), the insulating resin 4 reaches the lid cylindrical insertion portion 34a, but the thickness of the case near the injection port 32 is such that the case main body support leg 31 and the lid cylindrical insertion insertion. A double wall structure is formed by combining the portions 34a. Therefore, the strength of the case main body 30 increases due to the increase in the case thickness.

  Further, when the cavity 40 is large (FIG. 14), since the buried metal 35 is buried in the insulating resin 4, stress applied to the case main body 30 due to vibration or impact is concentrated on the buried metal 35, and the case main body 30 is concentrated. Such stress can be reduced. In addition, the same effect can be exhibited also in the case of FIG.

As described above, according to the third embodiment, when the cavity 40 is small, the thickness in the vicinity of the injection port 32 can be increased by the double wall structure of the case main body support leg portion 31 and the lid cylindrical fitting insertion portion 34a. The strength of the case itself can be increased. When the cavity 40 is large, the strength of the case itself is increased by concentrating stress generated by vibration or impact on the buried metal 35 embedded in the insulating resin 4.
Further, by providing the buried metal 35 with a lid body retaining recess 35b, it is possible to prevent the buried metal 35 from coming out of the insulating resin 4 and to suppress the increase of the cavity 40 by the amount buried in the insulating resin 4. .
As a result, in the third embodiment, even if the cavity 40 is generated, it can be permitted by increasing the case strength. Therefore, the step of adding the insulating resin 4 and eliminating the cavity 40 can be eliminated.

  In the present invention, each embodiment can be appropriately modified or omitted within the scope of the invention.

1 Primary coil 1a Primary terminal 1a3 Connection hole 2 Secondary coil 2a Secondary terminal 30 Case body (30L, 30R)
30L 1st case 30R 2nd case 31 Case body support leg,
31L First case side support leg 31R Second case side support leg 31a Convex portion of case main body support leg 31b Inner wall surface of case main body support leg 32 Inlet 33 Through hole 34 Lid 34a Lid tubular insertion Part 34b Recessed portion of the lid cylindrical fitting insertion part 35 Filling 35a Screw hole 35b Lid for retaining lid 35c Filling head 36 Mounting board mounting screw 4 Thermosetting insulating resin 5 Iron core 6 Mounting board 40 Cavity 100 Mold type Transformer.

Claims (7)

A case body formed by fitting the first case and the second case;
A case body support leg portion formed with an injection port for injecting an insulating resin filled in the case body and formed with the first case and the second case of the case body, and the injection port. With a lid to close,
A mold-type transformer characterized in that a lid-like cylindrical insertion portion that is inserted into the case body support leg portion from the inlet is formed in the lid body.   The plurality of recesses filled with the insulating resin as an adhesive are provided in the lid tubular insertion portion so as to face the inner wall surface of the case body support leg. The mold type transformer according to 1.   3. A convex portion is provided on an inner wall surface of the case main body support leg portion so as to be fitted into the concave portion and hold the fitting between the first case and the second case. Mold-type transformer as described.   4. The mold type transformer according to claim 3, wherein the lid has a screw hole for a case main body mounting screw, and embedded with a buried metal that relieves stress applied to the case main body.   5. The mold transformer according to claim 4, wherein the buried metal is extended to a length embedded in the insulating resin in the case body support leg.   6. The mold transformer according to claim 5, wherein the buried metal is provided with a recessed portion for preventing the lid from being removed at a buried portion in the insulating resin. The buried metal is embedded in the case main body when the insulating resin is contracted by the buried portion in the insulating resin and the double wall formed by the lid cylindrical fitting insertion portion and the case main body support leg. 6. The mold transformer according to claim 4, wherein the size of the generated cavity is suppressed and the size of the cavity is allowed.

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