JP2005294803A - Ignition coil for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition for an internal combustion engine which is capable of being easily mounted without increasing an axial dimension and includes a loose-prevention part of high stiffness. <P>SOLUTION: An ignition coil 15 for the internal combustion engine comprises: a cylindrical coil portion 20 including a primary coil 23 and a secondary coil 22, a ring-like energizing member 40 having elasticity in the radius direction which is fitted over the outer circumferential surface situated nearer the other end of a plug, and a ring-like pressure member 35 which is energized radially-outwardly by the energizing member and pressed to the inner circumference surface of the inlet port 12 of a plug hole 10 in a cylinder head. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ignition coil for an internal combustion engine, and particularly to one that is prevented from being pulled out from a plug hole due to vibration or the like.

  An internal combustion engine ignition coil (hereinafter abbreviated as “ignition coil”) includes a coil section, a control section at the upper end thereof, and a high-pressure tower section at the lower end of the coil section. The coil portion includes a primary coil and a secondary coil and has a cylindrical shape. The control unit controls the operation of the coil unit. The high-pressure tower part and the coil part are inserted into the insertion hole of the plug hole of the cylinder head, and the control part is accommodated in the inlet hole part. When the engine is operating, a small vibration is applied to the cylinder head, and this vibration is also transmitted to the ignition coil inserted into the plug hole. While the vibration is repeated, there is a concern that the fixing of the ignition coil to the plug hole will loosen and come out of the plug hole.

  In order to prevent extraction, various extraction preventing means are disposed between the control unit and the cylinder head. For example, a flange portion extending radially outward from the control unit is fixed to the upper surface of the cylinder head. In some cases, a locking piece extending downward from the control unit is locked to the cylinder head. The ignition coil 150 shown in FIGS. 7 and 8 includes a coil body 151 that houses a high voltage generator, and a connection leg 154 that houses a connection part that hangs downward and is electrically connected to the spark plug 160. It consists of and.

  On the lower surface of the coil main body 151, a pair of locking pieces 152 projecting downward with the connection leg 154 interposed therebetween is provided, and an outward hook-shaped locking portion 153 is formed at the lower end thereof. On the other hand, the rocker cover 155 is provided with a raised annular coil mounting portion 157 including mounting holes 156 having an inner diameter corresponding to the interval between the locking pieces 152. A locking release portion 159 that allows passage of the locking piece 153 is provided on the inner peripheral edge 158 of the coil mounting portion 157.

When attaching the ignition coil 150 to the rocker cover 155, the phases of the locking piece 153 and the locking release portion 159 are matched in the circumferential direction, and the connecting leg portion 154 is inserted into the coil mounting portion 157. Thereafter, when the ignition coil 150 is rotated to the left or right, the locking piece 153 is locked to the inner peripheral edge 158, and the ignition coil 150 is fixed so as not to come out.
JP-A-9-126112

  In the conventional example, the radial dimension of the coil main body 151 is small because the flange is not formed. However, the coil mounting portion 157 is raised and the axial dimension increases. Moreover, the phase alignment of the locking piece 153 and the locking release portion 159 is necessary at the time of insertion, which is troublesome. Furthermore, since the pair of locking pieces 153 extending from the coil main body 150 are elongated, the rigidity is weak, and they are easily bent or bent.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an ignition coil for an internal combustion engine that does not increase the axial dimension, is easy to mount, and has an extraction prevention portion with high rigidity. .

The inventor of the present application uses an urging means arranged on the inner peripheral side of an annular pressing member fitted near the end of the coil portion of the ignition coil on the side opposite to the plug side (usually the upper end portion). The present invention has been completed with the idea of urging outwardly in the radial direction toward the inner circumferential surface.
(1) An ignition coil for an internal combustion engine according to a first invention of the present application, as described in claim 1, is a columnar coil portion including a primary coil and a secondary coil, and a portion closer to an end opposite to the plug side of the coil portion. And an annular biasing member that is elastic in the radial direction and is fitted to the outer peripheral surface of the biasing member and biased radially outward by the biasing member, And an annular pressing member pressed against the inner peripheral surface of the inlet hole.

In this ignition coil, a pressing member interposed between an end portion of the coil portion opposite to the plug and the inlet hole portion of the plug hole and a biasing member that biases the pressing member radially outwardly are ignited from the plug hole. An extraction preventing portion for preventing the coil from being extracted is formed.
(2) An ignition coil for an internal combustion engine according to a second aspect of the present invention, as described in claim 5, is a cylindrical coil portion including a primary coil, a secondary coil and an outer peripheral core, and an anti-plug of a main body portion of the outer peripheral core. A biasing portion formed integrally with the main body portion at the side end and elastically deformable in the radial direction, and a plug hole of the cylinder head that is fitted to the outer peripheral side of the biasing portion and biased radially outward by the biasing portion. And an annular pressing member pressed against the inlet hole.

In this ignition coil, a pressing member that is interposed between an end portion of the coil portion opposite to the plug and the inlet hole portion of the plug hole, and a biasing portion that is a part of the outer peripheral core that biases the pressing member radially outward However, an extraction preventing portion for preventing the ignition coil from being extracted from the plug hole is formed.
(3) The ignition coil for an internal combustion engine according to the third invention is fitted to the coil portion including the primary coil and the secondary coil and the outer peripheral surface of the coil portion near the end opposite to the plug, and can be elastically deformed in the radial direction. And an annular pressing member that is urged radially outward by the urging member and pressed against the inlet hole of the plug hole of the shilling head.

  In this ignition coil, a pressing member interposed between the non-plug side end portion of the coil portion and the inlet hole portion of the plug hole, and a biasing member built in the pressing member and biasing the pressing member radially outward However, an extraction preventing portion for preventing the ignition coil from being extracted from the plug hole is formed.

(1) According to the ignition coil for an internal combustion engine according to the first invention of the present application, from the pressing member and the urging member disposed between the non-plug side end portion of the coil portion and the inlet hole portion of the plug hole. The extraction preventing portion configured as described above can prevent the ignition coil from being extracted from the plug hole without increasing the height. Further, the pressing member and the urging member can be easily mounted simply by fitting to the upper end portion of the coil portion, and since it has a cylindrical shape as a whole, the rigidity is high.

According to the ignition coil of the second aspect, thanks to the annular rib formed on the outer peripheral surface thereof, the close contact with the inner peripheral surface of the inlet hole portion of the pressing member is strengthened. According to the ignition coil of the third and fourth aspects, the biasing member can exert a large biasing force thanks to the deformed portion formed on the biasing member.
(2) According to the ignition coil for an internal combustion engine according to the second aspect of the present invention, the pressing member and the urging portion of the outer peripheral core disposed between the end portion on the side opposite to the plug of the coil portion and the inlet hole portion of the plug hole The extraction preventing portion made of can prevent the ignition coil from being extracted from the plug hole without increasing the height. Further, the pressing member and the outer peripheral core can be easily mounted simply by fitting to the upper end portion of the coil portion, and furthermore, since it has a cylindrical shape as a whole, the rigidity is high.

According to the ignition coil of the sixth aspect, the elastic deformability of the urging portion is improved by the circumferential slit formed between the urging portion of the outer peripheral core and the main body portion. According to the ignition coil of the seventh aspect, the urging portion of the outer peripheral core that is elastically deformed radially inwardly presses the pressing member against the inlet hole.
(3) According to the ignition coil according to the third aspect of the present invention, the pressing member and the urging member built in the pressing member are disposed between the opposite end portion of the coil portion and the inlet hole portion of the plug hole. The extraction preventing portion configured as described above can prevent the ignition coil from being extracted from the plug hole without increasing the height. Further, the pressing member and the urging member can be easily mounted simply by fitting to the upper end portion of the coil portion, and since it has a cylindrical shape as a whole, the rigidity is high. According to the ignition coil of the ninth and tenth aspects, since the urging member is integrated with the pressing member, the urging member is also mounted at the same time by fitting the pressing member to the outer peripheral side spool. Easy to install.

A. Engine Block, Plug Hole In an internal combustion engine such as an automobile engine, a plug hole is formed in the thickness direction of a cylinder head that constitutes a lid (head) of the cylinder block. The plug hole includes a thin and long insertion hole into which the coil part is inserted and a large and short inlet hole part in which the extraction preventing part is accommodated.
B. Ignition Coil The stick-type ignition coil of the present invention (hereinafter abbreviated as “ignition coil” if necessary) has a coil portion in the middle in the axial direction, a control portion at the upper end thereof, and a pull-out prevention between the coil portion and the plug hole. Part (pressing member and urging means).

<Coil unit, control unit>
The coil portion includes at least a central core, a secondary coil and a primary coil on the outer peripheral side, an outer peripheral core on the outer peripheral side, and the like. In the radial direction, the primary coil may be on the outer peripheral side, and the secondary coil may be on the outer peripheral side. The control unit is a portion that switches the primary current, and includes an insulating upper (circuit) case, and an igniter and a terminal housed therein. The upper case and the spool located on the outer peripheral side of the coil portion are coupled.
<Pressing member>
The pressing member is made of a stretchable material (for example, rubber) or the like, has an annular shape or a cylindrical shape as a whole, has at least a cylindrical portion, and can further have a flange portion at one end (for example, an upper end) of the cylindrical portion. The inner diameter is substantially equal to or slightly larger than the outer diameter of the upper end portion of the coil portion. A biasing member mounting recess may be provided on the inner peripheral surface. The outer diameter is substantially equal to the inner diameter of the inlet hole of the plug hole, and the outer peripheral surface can be provided with a plurality of annular ribs formed at a predetermined pitch in the axial direction. Furthermore, an insertion hole for inserting the biasing member can be provided in the middle portion in the thickness direction.

<Energizing means>
The function of the urging means is to press the outer peripheral surface of the pressing member toward the inner peripheral surface of the inlet hole portion of the plug hole so that the pressing member comes into close contact. Therefore, it is interposed between the outer peripheral surface near the upper end of the coil portion and the inner peripheral surface of the pressing member, is formed by a part of the outer peripheral core, or is inserted into the pressing member. Here, the upper end portion of the coil portion is the upper end portion of the spool located on the outer peripheral side. Specifically, it can be classified into the following three types.
(A) The first type urging means comprises an annular or cylindrical spring-like urging member fitted to the outer peripheral surface of the outer peripheral side spool. The axially intermediate portion has a deformable portion (biasing portion) that can be elastically deformed in the radial direction, bulges outward in the radial direction in a natural state, and elastically deforms radially inward when mounted. That is, the urging member is fitted to the outer peripheral surface of the outer peripheral side spool, the pressing member is fitted to the outer peripheral side of the urging member, and the urging member urges the pressing member outward in the radial direction. Note that a plurality of axial slots can be provided in the circumferential direction in the deformable portion.
(B) The second type urging means comprises a part of the outer peripheral core of the outermost layer of the coil portion. A thin cylindrical outer core may be mounted on the outer peripheral side of the spool and the winding located on the outer peripheral side. By forming an inverted T-shaped or cross-shaped slit at the upper end portion of the outer peripheral core, an integral main body portion and an urging portion are formed. The cross-sectional shape of the main body may be circular or C-shaped. The urging portion has a C-shaped cross section, and its outer diameter is larger than that of the main body portion of the outer core in the natural state. At the time of mounting, the urging portion is elastically deformed inward in the radial direction. That is, the pressing member is fitted to the outer peripheral side of the urging portion of the outer peripheral core fitted to the outer peripheral surface of the outer peripheral spool. As a result, the urging portion urges the pressing member outward in the radial direction.
(C) The third type urging means is built in the pressing member. Specifically, an insertion hole is formed in the intermediate portion in the thickness direction of the pressing member, and a coil spring that is elastically deformed in the radial direction is inserted into the insertion hole in a state of being contracted in the radial direction. The biasing member is not in contact with the outer peripheral surface of the outer peripheral side spool. The urging member urges the pressing member radially outward with a restoring force to the natural state. A C-shaped member that can be elastically deformed in the radial direction may be employed instead of the coil spring.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<First embodiment>
a. Configuration FIG. 1 shows a stick ignition coil 15 and a plug hole 10 of a cylinder head 13 into which the stick ignition coil 15 is inserted. The plug hole 10 includes a small-diameter insertion hole 11 having a circular cross section and a substantially uniform diameter, and a large-diameter inlet hole 12 formed in the opening. A spark plug (not shown) is fixed to the bottom of the insertion hole 11. The ignition coil 15 inserted into the plug hole 10 includes an axially middle coil portion 20, an upper end control portion 30, and a lower end high voltage tower portion (not shown).

  The central core 21 made of a magnetic material has a cylindrical shape and is arranged at the center of the coil portion 20. The secondary coil 22 is formed by winding a secondary winding 22b around an insulating, cylindrical secondary spool 22a. The primary coil 23 on the outer peripheral side is formed by winding a primary winding 23b on an insulating, cylindrical primary spool 23a. In the control unit 30, an igniter 32 is disposed in the circuit case 31, and an insulating resin (not shown) is filled therearound.

  As shown in FIGS. 1 and 2, the pressing member 35 is made of a rubber material and has a cylindrical shape as a whole. A large-diameter portion (flange portion) 37 having a short upper end and a small-diameter portion (cylindrical portion) 36 having a long middle to lower end are formed, and an annular step portion is formed therebetween. On the outer peripheral surface of the cylindrical portion 36, a plurality of annular ribs 39 are spaced apart at a predetermined pitch in the axial direction. A shallow annular recess 38 is formed on the inner peripheral surface of the cylindrical portion 36. The pressing member 35 is mounted on the outer peripheral surface of the upper portion of the primary coil 23 located on the outer peripheral side in the cylindrical portion 36 via a biasing member 40 described below, and the flange portion 37 is in close contact with the outer peripheral surface of the outer peripheral core. Yes. The flange portion 37 is not indispensable, and a pressing member having no flange portion can be employed.

  As shown in FIGS. 1 and 3, the urging member 40 is made of a spring material and has a thin cylindrical shape as a whole. It includes a long deformed portion 41 in the middle in the axial direction, a short upper end 45, and a short lower end 47. The upper half and the lower half are symmetrical with respect to the intermediate portion, and are accommodated in the depression 38 of the pressing member. Has been. The deformed portion 41 is composed of a bulging portion 42 bulging in an arc shape outward in the radial direction in a natural state, and a plurality of slits 43 extending in the axial direction are spaced between adjacent bulging portions 42 in the circumferential direction. Yes.

  At the time of assembly, first, the urging member 40 is inserted from the lower end side of the coil portion 20 and fitted to the outer peripheral surface of the upper portion of the primary coil 23. Thereafter, the pressing member 35 is similarly inserted from the lower end side of the coil portion 20 and fitted to the outer peripheral surface of the urging member 40. In addition, you may fit the press member 35 by which the urging | biasing member 40 was previously mounted | worn in the hollow 38 to the outer peripheral surface of the upper end part of the primary spool 23a. By fitting the pressing member 35 to the outer peripheral side of the urging member 40, the bulging portion 42 of the urging member 40 is elastically deformed inward in the radial direction by the small diameter portion 36, and the small diameter portion 36 is radially deformed by the reaction thereof. It is biased outward.

Thus, the spark plugs attached to the urging member 35 and the pressing member 40 are inserted into the plug hole 10. Then, when the coil portion 20 is inserted into the insertion hole 11 of the plug hole 10 and the pressing member 35 and the urging member 40 are accommodated in the inlet hole portion 12, the annular rib 39 on the outer peripheral surface of the pressing member 35 is urged. The deformed portion 41 of the member 40 is urged outward in the radial direction, and is strongly pressed against the inner peripheral surface of the inlet hole portion 11.
b. Effect According to the ignition coil of the first embodiment, it is possible to reliably prevent the ignition coil 15 from being pulled out from the plug hole 10 due to vibration or the like. This is because the elastic pressing member 35 is first urged radially outward by the spring-like urging member 40. Further, since the annular rib 39 is formed on the outer peripheral surface of the pressing member 35, it is easy to adhere to the inner peripheral surface of the insertion hole portion 12. Furthermore, since the bulging part 42 and the slit 43 are formed in the deformation part 41 of the urging member 40, the deformability is increased and a large urging force is obtained.

Moreover, since it is only necessary to fit the pressing member 35 and the biasing member 40 to the upper end of the coil portion, not only the mounting is easy, but the height (length) of the coil portion 20 and the control portion 30 does not increase. . Further, since the urging member 40 is made of a thin cylindrical member, the urging member 40 has a high rigidity and is free from damage. In addition, the flange portion 37 of the pressing member 35 is in close contact with the outer peripheral surface of the outer core 24 and seals between the outer core 24 and the primary spool 23a.
<Second embodiment>
In the second embodiment shown in FIG. 4, the urging means is formed on a part of the outer peripheral core 50 (see the outer peripheral core 24 in FIG. 1) fitted to the outer peripheral surface of the primary spool 23 a of the primary coil 23. It comprises a C-shaped biasing portion 53. More specifically, an axial slit 51 extending in the entire axial direction is formed in a thin cylindrical outer peripheral core 50 made of a spring material, and has a C-shaped cross section. A circumferential slit 52 that intersects the axial slit 51 and extends in the circumferential direction is formed at the boundary between the upper end portion and the intermediate portion. As a result, a main body portion 53 that is long in the axial direction and a short biasing portion 54 at its upper end are formed. In the natural state, the outer diameter of the urging portion 54 is larger than the outer diameter of the main body portion 53.

  When the assembly of the ignition coil 15 is completed, the outer peripheral core 50 forms the outermost layer in the coil portion 20, and the pressing member 35 is fitted to the outer peripheral side of the biasing portion 54. Therefore, when the coil part 20 is inserted into the insertion hole 11 and the pressing member 35 is accommodated in the inlet hole part 12, the urging part 54 is elastically deformed inward in the radial direction as it is inserted. In the insertion-completed state, the urging portion 54 urges the pressing member 35 outward in the radial direction to bring it into close contact with the inner peripheral surface of the inlet hole portion 12.

According to the second embodiment, the same effect as in the first embodiment can be obtained. In addition, as a unique effect, the urging portion 54 is formed of a part of the outer core 50, so that it is not necessary to prepare a separate and independent urging member and insert it on the inner peripheral side of the pressing member 35. As a result, the number of parts is reduced, and the labor for mounting the urging means is reduced.
<Third embodiment>
In the third embodiment shown in FIGS. 5 and 6, the urging member 80 is inserted into the circumferential portion 72 of the pressing member 70. That is, as shown in FIGS. 5 and 6A, the pressing member 70 includes a cylindrical portion 72 and a flange portion 75 at the upper end thereof. A plurality of annular ribs 73 are provided at a predetermined pitch in the axial direction over the entire outer peripheral surface of the cylindrical portion 72, and a circular dead hole 76 is formed in the middle portion in the thickness direction and opens at the lower end surface.

  The biasing member 80 comprises two identically shaped C-shaped rings 82 and 85. Each of the C-shaped rings 82 and 85 has slits 83 and 86 formed at one place in the circumferential direction, and the pair of opposed portions 84 and 87 can be elastically deformed in the radial direction. The C-shaped rings 82 and 85 are elastically deformed inward in the radial direction, and are stacked in the axial direction with the phases of the slits 83 and 86 being shifted in the circumferential direction. Yes.

  When assembled to the coil portion 20, the C-shaped rings 82 and 85 are previously inserted into the dead holes 76 of the pressing member 70, and the cylindrical portion 72 of the pressing member 70 into which the C-shaped rings 82 and 85 are inserted. May be fitted to the outer peripheral surface of the primary spool 23a. Then, the cylindrical portion 72 of the pressing member 70 is urged radially outward by the two rings 82 and 85. According to the third embodiment, the same effect as the first embodiment can be obtained. In addition, as a unique effect, since the pressing member 70 and the C-shaped rings 82 and 85 are integrated in advance, the pressing member 70 and the urging member 80 can be easily mounted on the primary spool 23a.

  A modification of the third embodiment is shown in FIG. Instead of the rings 82 and 85, the coil spring 100 of FIG. 6B may be inserted into the dead hole 76. The coil spring 100 is composed of a plurality of spirals 102 and is inserted into the dead hole 76 in a state of being elastically deformed so as to have a small radius, and urges the cylindrical portion outward in the radial direction. According to the coil spring 100, the same effects as those of the rings 82 and 85 can be obtained.

It is a principal part longitudinal cross-sectional view which shows 1st Example of this invention. It is a front view which shows the biasing member and press member which are a part of the said Example. It is a perspective view of the said urging member. (A) is a perspective view of the outer periphery core provided with the urging | biasing part used for 2nd Example of this invention, (b) is a top view similarly. It is principal part front sectional drawing which shows 3rd Example of this invention. (A) is a perspective view which shows the biasing member of 3rd Example, (b) is a perspective view which shows the modification of (a). It is a general view of a prior art example. It is a perspective view of the one part member of FIG.

Explanation of symbols

10: Plug hole 12: Entrance hole 15: Ignition coil 20: Coil part 22: Secondary coil 23: Primary coil 23a: Primary spool 35, 70: Pressing member 40, 80: Energizing member 42: Swelling part 50: Outer core 53: Body part 54: Biasing part 82, 85: C-shaped ring

Claims (10)

A cylindrical coil portion (20) including a primary coil (23) and a secondary coil (22);
An annular urging member (40) that is fitted to the outer peripheral surface of the coil portion near the end on the side opposite to the plug and is elastic in the radial direction;
An annular member that is fitted to the outer peripheral surface of the urging member, is urged radially outward by the urging member, and is pressed against the inner peripheral surface of the inlet hole (12) of the plug hole (10) of the cylinder head. A pressing member (35);
An ignition coil for an internal combustion engine comprising:   2. The ignition coil according to claim 1, wherein the pressing member is extendable and contractable in a radial direction, and a plurality of annular ribs are provided in an axial direction on an outer peripheral surface.   2. The ignition coil according to claim 1, wherein the urging member has a spring property, and has a deformed portion that is mounted in a state of bulging outward in the radial direction in a natural state and elastically deforming inward in the radial direction.   The ignition coil according to claim 3, wherein the deforming portion includes a plurality of slits extending in the axial direction and spaced apart in the circumferential direction. A cylindrical coil portion (15) including a primary coil (23), a secondary coil (22) and an outer peripheral core (50);
An urging portion (54) formed integrally with the main body portion at an end opposite to the plug side of the main body portion (53) of the outer peripheral core and elastically deformable in a radial direction;
An annular pressing member (fitted to the outer peripheral side of the biasing portion, biased radially outward by the biasing portion, and pressed against the inlet hole (11) of the plug hole (10) of the cylinder head ( 35)
An internal combustion engine ignition coil comprising:   6. The ignition coil according to claim 5, wherein the urging portion has a C-shaped cross section, and a circumferential slit is formed between the urging portion and the main body portion.   The ignition coil according to claim 6, wherein an outer diameter of the urging portion is larger than an outer diameter of the main body portion in a natural state, and is mounted in a state of being elastically deformed radially inward. A coil portion (15) including a primary coil (23) and a secondary coil (21);
A biasing member (82, 85) that is fitted to the outer peripheral surface of the coil portion near the end on the side opposite to the plug and is elastically deformable in the radial direction is built in and biased outward in the radial direction by the biasing member. An annular pressing member (70) pressed against the inlet hole (11) of the plug hole (10) of the shilling head;
An ignition coil comprising:   The ignition coil according to claim 8, wherein the urging member is a coil spring inserted into the pressing member.   The ignition coil according to claim 8, wherein the biasing member is a C-shaped member inserted into the pressing member.

Images