JP5892009B2 - Coil device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a coil device and a manufacturing method thereof.

The coil device that constitutes a part of the solenoid has a structure in which a coil formed by winding a bobbin with a winding is fitted in a yoke (fixed iron core). Here, in the oil-immersed solenoid, a molded coil obtained by molding a synthetic resin exterior body around the coil is applied.
Conventionally, as an example of this mold coil, as shown in Patent Document 1 below, a structure in which an exterior body seamlessly covers the entire surface around a coil (bobbin) by float forming is known as having excellent sealing properties. There is a track record.

JP 2002-28950 A

By the way, in the above-described floating molding, the bobbin is held in the cavity with a pin until the final stage of molding, and when the final stage is reached, the pin is retracted and held in a state of floating in the resin. The bobbin may tilt. Therefore, it is necessary to set the molded body to be thick so that the bobbin is not exposed even if it is tilted to some extent, but if so, the mold coil becomes larger and the entire coil device including the yoke becomes larger, and the mounting space There is a problem that it leads to an increase in weight and an increase in weight.
The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a coil device that achieves miniaturization while ensuring sealing performance.

Coil device of the present invention, a molded coil around the entire synthetic resin sheathing body coil is made form obtained by winding a winding on a bobbin, the molded coil is fitted from one side A coil device including a yoke having an annular groove shape, wherein the inner peripheral surface of the bobbin has a thickness greater than the thickness of the inner peripheral portion of the exterior body formed to cover the inner peripheral surface of the bobbin. An axial direction sandwiching the sandwiched portion in the inner peripheral portion of the exterior body, with a sandwiched portion having a large height dimension and projecting from the projecting portion from the inner peripheral portion. It is characterized in that seal rings that are elastically compressed between the opposing inner peripheral walls of the yoke are mounted at two front and rear positions.

  The coil device manufacturing method of the present invention is a yoke in which a molded coil in which a synthetic resin outer body is formed by molding around a coil in which a wire is wound around a bobbin has an annular groove shape opened on one side surface. A method of manufacturing a coil device that is fitted into a cavity, wherein the coil is held in a cavity while sandwiching a sandwiched portion that is projected in advance on the inner peripheral surface of the bobbin when the pair of molds is closed. A step of holding, a step of injecting a synthetic resin into the cavity to form an exterior body, a step of taking out a molded product out of the mold as the mold opens, and a portion of the molded product protruding from the exterior body of the sandwiched portion Cutting the portion to form the mold coil, and fitting the mold coil to the yoke while sealing the seal coil with a seal ring at two positions in the axial direction of the remaining sandwiched portion. Characterized in where it was Bei.

  According to the present invention, the coil is supported in a substantially floating state in the cavity of the mold while being sandwiched by the sandwiched portion that is formed in advance on the inner peripheral surface of the bobbin, and is melted into the cavity from this state. When the resin is injected and the mold is opened when the resin is cured, the outer package is formed over the entire surface around the coil, and the molded product with the tip of the sandwiched portion protruding from the inner periphery of the outer package is taken out. Then, a molded coil is obtained by cutting out the part which protruded from the inner peripheral part of the exterior body in a clamped part among molded articles. The coil device is assembled by fitting the molded coil to the yoke while sealing the entire periphery of the sandwiched portion in the inner circumferential portion of the exterior body in the axial direction with the seal ring over the entire circumference. .

When forming the exterior body on the entire surface around the coil, the clamped part protruding from the inner peripheral surface of the bobbin is sandwiched between the two molds, so that the coil is supported firmly in a floating state in the cavity. Can be held in position. Therefore, it is not necessary to increase the volume of the cavity, that is, to increase the thickness of the exterior body. A mold coil can be obtained by cutting out the protruding portion of the sandwiched portion. However, the outer casing can be made thin as described above, so that the size can be reduced.
The mold coil is fitted to the yoke, and at this time, there is a risk of flooding from the interface with the sandwiched portion remaining on the inner periphery of the exterior body, but the two axially front and rear positions where the interface exists are sealed. Since the entire circumference is sealed by the ring, it is possible to prevent water from entering the coil side from the interface.
That is, it is possible to reduce the size of the molded coil while ensuring sealing performance, and to reduce the size of the entire coil device including the yoke, thereby reducing the mounting space and weight.

The following configuration may also be used.
(1) The sandwiched portion is configured by a plurality of protrusions directed to the center of the bobbin being scattered along the circumferential direction. The cutting process of the protruding portion of the sandwiched portion can be easily performed.
(2) The sandwiched portion is formed in the form of a ridge extending over the entire circumference. The coil can be held more firmly in the mold.

  ADVANTAGE OF THE INVENTION According to this invention, the coil apparatus which implement | achieved size reduction while ensuring sealing performance can be obtained.

Sectional drawing of the state which set the coil which concerns on one Embodiment of this invention in the shaping | molding die Plan view of movable mold side Cross section during molding Front view of molded product by molding Sectional view Front view of mold coil Sectional view showing the operation of assembling the mold coil to the yoke Cross section when assembly is complete Partial enlarged view of FIG.

<Embodiment>
An embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 7, the coil device of this embodiment includes a molded coil 10 and a yoke 40 (fixed iron core). In addition, two seal rings 50 and a C ring 52 are provided.

  In the molded coil 10, a coil 13 is formed by winding a copper wire 13 around a synthetic resin bobbin 12, and a synthetic resin outer body 20 is formed around the coil 11 by molding. As shown in FIG. 6, it is formed in a ring shape as a whole. In addition, a connection portion 23 in which a pair of connection terminals 15 connected to the winding 13 are arranged and embedded is projected from a part of the outer periphery on one side surface of the exterior body 20.

  The molding of the exterior body 20 will be described. As shown in FIGS. 1 and 2, on the inner peripheral surface of the bobbin 12 constituting the coil 11, four protrusions 16 constituting the sandwiched portion are circumferentially spaced by 90 degrees at the center width position. It is formed along. Specifically, as shown in FIG. 3, the protrusion 16 has a prismatic shape having a height slightly more than twice the thickness of the inner peripheral portion 21 of the exterior body 20 and is directed to the center of the bobbin 12. Is formed.

On the other hand, as the mold K, as shown in FIG. 1, a pair of a fixed mold 60A and a movable mold 60B are provided. The fixed mold 60A is provided with a split mold for molding the connecting portion 23 of the exterior body 20, but this is not shown in the figure.
As shown in FIG. 2, an annular groove 61 that is slightly larger than the coil 11 is formed on the joint surface of the movable mold 60 </ b> B, and the cavity 62 is configured to form the outer package 20 when the mold is closed. It has come to be. On the inner peripheral side of the annular groove 61, four insertion grooves 63 into which the protrusions 16 protruding from the inner peripheral surface of the bobbin 12 can be tightly inserted are substantially half of the annular groove 61 from the joint surface. A cut is formed to the depth position.
On the other hand, when the mold is closed, the fixed mold 60A closely enters the insertion groove 63 at each position opposed to the insertion groove 63 formed in the joint surface of the movable mold 60B. Thus, a pin 64 that can hold the protrusion 16 is provided.

  A cross-shaped runner 65 is formed on the joint surface of the movable die 60B, and the gate 66 at each end faces the annular groove 61 at a position that is 45 degrees out of phase with the formation position of the insertion groove 63. A sprue 68 communicating with the center of the runner 65 is formed in the fixed mold 60A.

  A procedure for forming the outer package 20 will be described. In the state where the mold is opened, the coil 11 is set with respect to the movable mold 60B. Specifically, as shown in FIG. 2, the four protrusions 16 are inserted into the insertion groove 63 and the coil 11 is inserted into the annular groove 61. Mated with clearance. Subsequently, when the mold is closed as shown in FIG. 1, the clamping pin 64 of the fixed mold 60A enters the insertion groove 63, the protrusion 16 is clamped between the groove bottom of the insertion groove 63, and the coil 11 is It is supported in a substantially floating state in 62.

  From this state, molten resin is injected into the cavity 62 through the sprue 68, the runner 65, and the gates 66. When the resin is cured after a predetermined time, the mold is opened and the molded product 10X is taken out of the mold. As shown in FIGS. 4 and 5, the molded product 10 </ b> X has a structure in which an exterior body 20 is formed over the entire surface around the coil 11, and the tip of the protrusion 16 (clamped) from the inner peripheral portion 21 of the exterior body 20. This is a structure with a protruding portion).

  After the molded product 10X is taken out from the mold K, the tip of each projection 16 protruding from the inner peripheral portion 21 of the exterior body 20 is cut off so as to be flush with the inner surface of the inner peripheral portion 21. Thereby, as shown in FIG.6 and FIG.7, the mold coil 11 is completed. In other words, in this molded coil 11, the cut ends of the protrusions 16 </ b> C after cutting are the same inner surface at four positions spaced at equal angles (90 degrees) at the substantially central width position of the inner surface of the inner peripheral portion 21 of the outer package 20. Exposed in a flush state.

  As shown in FIG. 7, the yoke 40 is formed in an annular groove shape that allows the molded coil 10 as a finished product to be tightly fitted from one side. As shown in FIG. 8, the depth of the fitting groove 41 of the yoke 40 is set to be larger than the width of the molded coil 11 by a predetermined dimension.

  On the other hand, the molded coil 10 is properly fitted to the groove surface 44 of the inner peripheral wall 43 of the yoke 40 (the peripheral surface facing the inner peripheral portion 21 of the exterior body 20) to the back of the fitting groove 41 of the yoke 40. In the case, the mounting grooves 45 to which the seal rings 50 are fitted are provided on the entire circumference on both the front and rear sides in the axial direction across the position corresponding to the cut end face of the protrusion 16C exposed on the inner surface of the inner peripheral portion 21 of the exterior body 20. It is formed over.

  Further, the fitting of the exterior body 20 when the molded coil 10 is properly fitted to the inner end of the groove surface 44 of the inner peripheral wall 43 of the yoke 40, specifically, the mold coil 10 is properly fitted to the back of the fitting groove 41 of the yoke 40. A mounting groove 47 for fitting the C-ring 52 to prevent the molded coil 11 from coming off is formed at a position corresponding to the position immediately after the side surface in the rearward direction.

An example of the procedure for assembling the coil device according to this embodiment will be described again.
As described in detail above, the protrusion 16 is formed in advance on the inner peripheral surface of the bobbin 12 constituting the coil 11. In order to form the mold coil 11, the coil 11 is supported in a substantially floating state in the cavity 62 of the mold K while sandwiching the protrusion 16, and a molten resin is injected into the cavity 62 to mold. Thereafter, when the mold is opened, the outer package 20 is formed over the entire surface around the coil 11, and the molded product 10 </ b> X in which the tip of the protrusion 16 protrudes from the inner peripheral portion 21 of the outer package 20 is taken out. The molded coil 11 is obtained by cutting out a portion of the molded product 10X that protrudes from the inner peripheral portion 21 of the exterior body 20 in the protrusion 16.

  On the other hand, as shown in FIG. 7, the seal rings 50 are fitted into the two mounting grooves 45 formed in the groove surface 44 of the inner peripheral wall 43 of the yoke 40. Then, the molded coil 11 formed as described above is fitted into the fitting groove 41 of the yoke 40 as shown by the arrow in FIG. By fitting the C ring 52 into the mounting groove 47, the mold coil 11 is prevented from coming off, and the assembly of the coil device is completed. At this time, as shown in detail in FIG. 9, the seal ring 50 is disposed at the inner periphery of the exterior body 20 at two positions in the front and rear in the axial direction across the embedded position of the protrusion 16 </ b> C remaining in the inner periphery 21 of the exterior body 20. Between the inner surface of the portion 21 and the groove bottom of the mounting groove 45, the whole surface is elastically compressed to be in a sealed state.

  According to the coil device of this embodiment, when forming the molded coil 11 whose entire surface around the coil 11 is covered with the exterior body 20, the protrusions 16 protruding from the inner peripheral surface of the bobbin 12 are formed on both molds 60 </ b> A and 60 </ b> B. Since the coil 11 is supported in a floating state in the cavity 62, the coil 11 can be firmly held in place. Therefore, it is not necessary to increase the volume of the cavity 62, that is, to make the exterior body 20 thicker. Although the mold coil 11 is obtained by cutting off the protruding portion of the protrusion 16, the exterior body 20 can be made thin as described above, so that the size can be reduced.

The mold coil 11 is fitted to the yoke 40, and at this time, there is a possibility that the mold coil 11 may be submerged from the interface 17 with the protrusion 16C remaining on the inner peripheral portion 21 of the exterior body 20. Since the two places are sealed over the entire circumference by the seal ring 50, it is possible to prevent water from entering the coil 11 side from the interface 17.
That is, it is possible to reduce the size of the molded coil 11 while ensuring the sealing property, and to reduce the size of the entire coil device including the yoke 40, thereby reducing the mounting space and the weight.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the case where the sandwiched portion provided on the inner periphery of the bobbin is configured by arranging four protrusions at equiangular intervals, but the number of the protrusions is arbitrarily three or more. It is.
(2) Further, the sandwiched portion may be formed in the form of a ridge extending over the entire circumference. In this case, the coil can be held in the mold by widening the area sandwiched by the mold. It can be performed more firmly.
(3) In the above embodiment, the C-ring is exemplified as a stopper for preventing the molded coil from coming off. However, the present invention is not limited to this, and other stoppers such as a retaining ring attached in a bayonet form may be used. Other types of retaining means may be applied.

DESCRIPTION OF SYMBOLS 10 ... Mold coil 11 ... Coil 12 ... Bobbin 13 ... Winding 16 ... Protrusion (clamped part)
16C ... Projection (after excision) 17 ... Interface 20 ... Exterior body 21 ... Inner circumference 40 ... Yoke 43 ... Inner circumference wall 44 ... Groove surface 45 ... Mounting groove 50 ... Seal ring 60A ... Fixed type 60B ... Movable type 62 ... Cavity 63 ... Insertion groove 64 ... Holding pin K ... Mold

Claims (4)

A mold coil around the entire synthetic resin sheathing body coil is made form obtained by winding a winding on a bobbin, a yoke forming the annular groove of the molded coil is fitted from one side A coil device comprising:
The inner peripheral surface of the bobbin has a height dimension larger than the thickness of the inner peripheral portion of the exterior body formed so as to cover the inner peripheral surface of the bobbin, and a protruding portion from the inner peripheral portion The nipped part that can be cut out is formed protruding,
A seal ring that is elastically compressed between the opposing inner peripheral walls of the yoke is attached to two axially front and rear positions sandwiching the sandwiched portion in the inner peripheral portion of the exterior body. Coil device.   The coil device according to claim 1, wherein the sandwiched portion is formed by a plurality of protrusions directed to the center of the bobbin being scattered along the circumferential direction.   The coil device according to claim 1, wherein the sandwiched portion is formed in the form of a ridge extending over the entire circumference. Manufacture of a coil device in which a molded coil, in which a synthetic resin exterior body is formed by molding around a coil in which a wire is wound around a bobbin, is fitted into a yoke having an annular groove shape opened on one side surface A method,
Holding the coil in the cavity while sandwiching a sandwiched portion formed in advance on the inner peripheral surface of the bobbin when the pair of molds is closed;
A step of injecting a synthetic resin into the cavity to form an exterior body and then taking the molded product out of the mold with mold opening;
Cutting the portion of the molded part protruding from the exterior body of the sandwiched part to form the mold coil; and
Fitting the mold coil to the yoke while being sealed with a seal ring at two positions in the axial direction of the remaining sandwiched portion;
The manufacturing method of the coil apparatus characterized by the above-mentioned.

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