JP6491887B2 - Ignition coil for internal combustion engine - Google Patents

Description

  The present invention relates to an ignition coil for an internal combustion engine, and is particularly suitable when a structure surface is formed by two types of resin structures.

  In recent years, for internal combustion engines used in automobiles and the like, a method for producing a caseless outer surface structure of an ignition coil has been studied (Japanese Patent Laid-Open No. 2009-182137). In such a manufacturing method, parts such as a coil assembly are arranged in a cavity in a mold, and an outer surface structure is formed by an overmolding method. For this reason, the resin structure formed around the coil assembly and the resin structure formed around the high-voltage terminal have their surfaces formed as one structure.

JP 2009-182137 A

  However, according to the technique of Patent Document 1, there is a problem that parts must be mounted inside the mold cavity, and the work at the time of mounting the parts becomes complicated. If attention is paid to the work at the time of conventional mounting, the work of providing a coil case as an outer surface structure and mounting a coil assembly or the like on this is made easier.

  Under such circumstances, it is also conceivable to mount a coil assembly or the like on a predetermined resin structure, and then attach the entire assembly to a mold cavity and overmold it. However, in this case, separation occurs between the resin structure in which the coil assembly is mounted in advance and the resin structure formed by overmolding as a boundary, resulting in a structural or circuit malfunction.

  In view of the above problems, an object of the present invention is to provide an ignition coil for an internal combustion engine that can suppress relative movement of these resin structures even when boundaries between different resin structures are formed.

In order to solve the above problems, the present invention has the following configuration of an ignition coil for an internal combustion engine. That is, a coil assembly, a structure made of a first resin material, a high-pressure side structure on which a coil mounting portion for mounting the coil assembly is formed, and a second resin different from the first resin material a structure made of a material and a coil side structure formed by covering the surrounding at least a portion of the coil assembly, both sides of the outer plate portion of the coil mounting portion is covered by said coil side structure The surface of the outer edge plate portion of the coil mounting portion has a substantially circular main portion and a shape that protrudes in the radial direction from the main portion .

  Preferably, the high voltage side structure is covered with the coil side structure from the cylindrical body storing the high voltage terminal to the outer edge plate.

  Preferably, the outer edge plate part is formed with a relative movement prevention element formed of any one of a hole part, a concave part, a convex part, or a notch part. More preferably, the outer edge plate part is formed with an array along the contour of the outer edge plate part, wherein the relative movement blocking elements formed by any of the hole part, the concave part, the convex part, or the notch part are formed. To do.

Preferably, the relative movement preventing element includes a first element that forms a resin filling path in a direction substantially parallel to a main surface of the outer edge plate portion, and a resin filling path in a direction substantially perpendicular to the main surface of the outer edge plate portion. A second element to be formed,
The first element is arranged in a region where the second element is interrupted in an array in which a plurality of the second elements are arranged.

  Preferably, the second resin material is made of a polyamide resin.

  According to the ignition coil for an internal combustion engine according to the present invention, since an element for preventing relative movement between adjacent resin structures is provided, protection on the resin structure and the circuit function is achieved.

The figure which shows the internal structure of the ignition coil for internal combustion engines which concerns on embodiment. The figure which shows the external appearance of the ignition coil for internal combustion engines which concerns on embodiment. The figure explaining in detail the outer edge board part of the ignition coil for internal combustion engines which concerns on embodiment. The ignition coil for internal combustion engines which concerns on embodiment (other examples).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an internal configuration of an ignition coil for an internal combustion engine according to the present embodiment. In this figure, a perspective view of an ignition coil for an internal combustion engine (hereinafter referred to as an ignition coil) is shown in (a), a front view of the ignition coil is shown in (b), and a side view of the ignition coil ( c). Please refer to these appropriately in accordance with the following description.

  As shown in the figure, the internal structure of the ignition coil includes a coil assembly and a high-pressure side structure 130. Among these, the high pressure side structure 130 is made of a first resin material such as PBT (Polybutylene Terephthalate) or PPS (Poly Phenylene Sulfide), thereby forming a structure. However, the resins listed here are merely representative examples and are not limited thereto.

  In the high voltage side structure 131, a coil mounting portion and a high voltage terminal accommodating portion are integrally formed. Among these, the coil mounting portion mainly includes a dish-like body 132 that is recessed in the plug direction and an outer edge plate portion 133 that is provided so as to circulate its outer edge with a predetermined plate width. Among these, the coil assembly is mounted on the surface of the recess of the dish-like body 132. The inside of the high voltage terminal accommodating portion is a cylindrical body, and a high voltage terminal (not shown) is provided at the inner end of the cylindrical body. The high-voltage terminal is electrically connected to the ignition plug of the internal combustion engine via a conductor (such as a spring) inserted into the cylindrical body.

  In the coil assembly, a secondary coil 120 and a primary coil (not shown) are combined, and these coils are arranged coaxially with respect to an internal I-shaped iron core (not shown). And the outer periphery iron cores 102 and 103 are arrange | positioned on the outer periphery of these components groups so that this may be enclosed. Thus, a closed path is formed around both the coils so as to surround the inside and outside of the coil assembly itself.

  In the present embodiment, an igniter 150 is provided in the coil assembly, and a plurality of terminals are arranged on a holder that holds the igniter 150. One of these terminals is connected to a battery power supply, the other is input with a drive signal, and the other is wired so as to match the GND potential. Further, these terminals are appropriately connected to the terminal of the igniter 150, the energization terminal of the primary coil, and the like. On the other hand, the secondary coil has one end electrically connected to the high voltage terminal and the other end electrically connected to the GND side.

  When the coil assembly configured as described above receives the ignition signal, the primary current starts to rise, and generates a negative high voltage in response to the interruption of the ignition signal. Therefore, the negative high voltage is applied to the high voltage terminal and discharges the plug gap of the spark plug.

  The assembly of the coil assembly and the high-pressure side structure 130 described with reference to FIG. 1 is called an intermediate assembly assembled in the previous stage of mounting in the mold cavity. After the intermediate assembly is set in the cavity of the mold, the second resin material is overmolded to form the coil side structure 140 of the ignition coil. As described above, in this embodiment, in order to avoid the trouble of directly attaching the coil assembly component to the mold cavity, the intermediate assembly is manufactured in advance and the procedure for mounting it to the mold cavity is taken. .

  As shown in FIG. 2, the coil-side structure 140 includes a covering portion 141 that directly covers a part of the coil assembly, and an outer layer portion 142 that covers a part of the high-pressure side structure (specifically, the high-pressure structure A part covering the body dish-like body from the outside), a shell-like part 143 in which the holder terminal is accommodated, and a flange part 144 in which a metal bush is embedded are integrally formed. Further, the structure (coil side structure) made of the second resin material surrounds a part of the high-pressure side structure, and a part of the high-pressure structure is exposed.

  As shown in FIG. 3A, in the region where the high-voltage side structure 130 and the coil-side structure 140 are adjacent to each other, a boundary that causes the relative movement of both is formed. In particular, in the ignition coil 100 according to the present embodiment, the first resin material and the second resin material are different materials. “Different” here includes physical and chemical differences such as differences in physical properties of the two or differences in composition of both, and is included if any cause that may cause separation between the resins at the boundary is recognized. . For example, when the two resins are compared, if the thermal expansion coefficient is different, this is the cause of peeling at the boundary (difference in physical properties), and if a decrease in the binding strength of both is recognized due to the difference in composition, this is the boundary. This is a cause of peeling (composition difference).

  Specifically, it is conceivable to employ a polyamide resin (such as PA6) as the second resin material used for the coil-side structure 140. Such a polyamide resin (Polyamide resin) is advantageous in that it generates less cracks around the iron core than PBT, PPS, and the like, and the buffer material around the iron core can be omitted. On the other hand, in the present embodiment, the high-pressure side structure 130 is composed of PBT or the like, and this difference in composition increases the risk of peeling at the resin boundary.

  Therefore, in the ignition coil according to the present embodiment, as shown in FIG. 3A, the coil-side structure is formed on both surfaces of the coil mounting portion from the cylindrical body 131 to the outer edge plate portion 133 via the dish-like body 132. By covering and contacting 140 resin structures, defects related to peeling are effectively prevented. In particular, the outer edge plate portion 133 of the coil mounting portion has a sufficiently large surface area when it is configured to surround the outside of the outer shape of the dish-like body 132. For this reason, the outer edge plate portion 133 has a sufficient surface adhesion force (one of the elements for preventing relative movement) derived from the shape thereof, and peeling and relative movement between the resin structures are suppressed.

  Further, as described above, in the present embodiment, the outer edge plate portion 133 is disposed substantially perpendicular to the axial direction of the cylindrical body 131. For this reason, in this ignition coil 100, it is set as the structure where peeling with the vibration to an axial direction does not arise easily.

  Moreover, as shown in FIG.3 (b), the outer edge board part 133 is provided with the recessed part 136 (136a, 136b, 136c). Each of the recesses 136 is filled with the second resin structure in its interior, thereby achieving a pawl function of relative movement around the axial direction (one of the elements that prevents relative movement). The accompanying peeling between the resin structures is prevented. In particular, such a concave portion is formed in an array along the outline of the outer edge plate portion 133, so that its function is exhibited to the maximum.

  In the present embodiment, as one of the elements that prevent relative movement (hereinafter referred to as “relative movement blocking element”), the formation of the recess 136 in the outer edge plate portion 133 has been introduced. However, this is only one embodiment, and the concave portion may be replaced with a convex portion. Moreover, what is made into the recessed part also includes the form which is not penetrated as a matter of course including a through hole.

  FIG. 3B shows a view in which a part of the outer edge plate portion 133 is observed from the coil mounting side toward the ignition plug. The surface of the outer edge plate portion 133 according to the present embodiment has a shape formed by a combination of a substantially circular main body portion 134 and a rectangular portion 135 protruding radially from the circular shape. As described above, in the present embodiment, the main body portion 134 has a circular shape, and there is a concern about relative movement around the central axis of the shape. Therefore, a portion protruding from the edge of the circular shape is used as an element to prevent this. Is made into an integral shape. In particular, in the present embodiment, an igniter 150 is mounted at that location (rectangular portion 135), and effective use of the mounting space is also achieved. In addition, about the main-body part 134, you may give the device which acquires the further relative movement prevention effect by processing a circular-shaped outline part into a tooth shape (notch processing).

  FIG. 4 shows a modification of the above-described embodiment. FIG. 4A shows an intermediate assembly, and FIG. 4B shows a high-pressure side structure. In the description of the figure, the same reference numerals are given to those already described, and the description thereof is omitted. Hereinafter, the embodiment relating to FIG. 4 will be referred to as “another embodiment” and will be described.

  As shown in FIG. 4A, in the intermediate assembly according to another embodiment, a notched portion is provided on the outer peripheral surface of the outer edge plate portion 133, and the overmolded resin is solidified in the space of the notched portion. Therefore, this lacking part functions as a relative movement prevention element, and this will be referred to as a first element 136p. The first element 136q guides the resin filling path Rt1 in a direction substantially parallel to the main surface of the outer edge plate portion 133 (a plate surface perpendicular to the axial direction of the cylindrical body), and overmolds the mold cavity. When filling of the molten resin is started, the molten resin flows from the outside to the inside of the intermediate assembly through the first element 136q.

  FIG. 4B shows a state in which the mounted parts are removed in order to explain the structure of the outer edge plate portion 133. As shown in the figure, the outer edge plate portion 133 is substantially perpendicular to the axial center of the cylindrical body in which the high-voltage terminal is accommodated, and further, a protruding frame is formed so as to surround the peripheral surface. The projecting frame has a circumferential shape along the outer peripheral surface, and the first elements 136q are also formed and arranged in a circumferential shape accordingly.

  Further, the outer edge plate portion 133 is formed with a hole 136p on the inner diameter side of the protruding frame, and a substantially vertical communication path is formed on the main surface of the outer edge plate portion 133. A plurality of the holes 136p are arranged along the inner side of the previous frame-like body, which are also used as a route for the molten resin and are finally filled with the solidified resin. Accordingly, even in the hole 136p, it is assumed that the function as a relative movement preventing function is exhibited, and this is hereinafter referred to as a second element 136p. As shown in the figure, the second elements 136p are arranged intermittently, so that an area for interrupting the second elements 136p is provided. In such a region, the structure of the outer edge plate portion 133 is left as a bottom surface inside and outside the outer edge plate portion 133.

  As described above, in the embodiment shown in the figure, two types of relative movement preventing elements are provided, and the first element 136q is arranged in a region where the second elements 136p are disconnected. As described above, at the portion where the resin filling path Rt1 forms a flow in the horizontal direction, the bottom surface structure of the outer edge plate portion 133 in which the second element 136p is excluded from the region is secured. Thereby, the bottom structure in the vicinity of the resin filling path of the outer edge plate portion 133 is secured with sufficient strength to withstand the boundary friction of the molten resin, and is free from deformation caused by the flow of the molten resin.

DESCRIPTION OF SYMBOLS 100 ignition coil for internal combustion engines, 102 1st outer periphery iron core, 103 2nd outer periphery iron core, 120 secondary coil, 131 high voltage | pressure side structure, 132 mounting part, 133 outer edge board part, 136 recessed part, 140 coil side Structure, 141 covering, 142 outer layer, 143 shell, 144 flange.

Claims (6)

A coil assembly;
A high pressure side structure having a coil mounting portion on which the coil assembly is mounted, the structure being made of a first resin material;
A structure made of a second resin material different from the first resin material, the coil side structure covering at least a part of the periphery of the coil assembly,
Both surfaces of the outer edge plate portion of the coil mounting portion are covered with the coil side structure ,
An ignition coil for an internal combustion engine, characterized in that a surface of an outer edge plate portion of the coil mounting portion is formed of a substantially circular main portion and a rectangular portion protruding radially from the main portion .   2. The ignition coil for an internal combustion engine according to claim 1, wherein the high-pressure side structure is covered with the coil-side structure from a cylindrical body storing a high-voltage terminal to the outer edge plate portion.   3. The internal combustion engine according to claim 1, wherein the outer edge plate portion is formed with a relative movement prevention element formed of any one of a hole portion, a concave portion, a convex portion, or a notch portion. Ignition coil.   The outer edge plate portion is formed with an array of relative movement prevention elements formed of any one of a hole, a concave portion, a convex portion, or a notch portion along an outline of the outer edge plate portion. The ignition coil for an internal combustion engine according to claim 1 or 2. The relative movement blocking element includes a first element that forms a resin filling path in a direction substantially parallel to the main surface of the outer edge plate portion, and a first element that forms a resin filling route in a direction substantially perpendicular to the main surface of the outer edge plate portion. It consists of two elements,
The said 1st element is arrange | positioned in the area | region where the said 2nd element has interrupted among the arrangement | sequences in which the said 2nd element is arranged in multiple numbers, The Claim 3 or Claim 4 characterized by the above-mentioned. 2. An ignition coil for an internal combustion engine according to 1.   The ignition coil for an internal combustion engine according to any one of claims 1 to 5, wherein the second resin material is made of a polyamide resin.

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