JP4124602B2 - Internal combustion engine head cover assembly - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a head cover assembly having a power distribution plate unit that is mounted on a head cover of an internal combustion engine and in which an electrical component such as an ignition coil and a wiring circuit thereof are mounted in advance.
[0002]
[Prior art]
In an internal combustion engine for automobiles, a large number of electric parts are conventionally provided. For example, in a spark ignition internal combustion engine, an ignition coil for supplying a high voltage to the spark plug is provided for each cylinder. If these plurality of electrical components are electrically connected to the engine control unit by wire harnesses, respectively, the wiring work becomes very complicated and the connection state tends to be incomplete.
[0003]
Thus, various proposals have been made in the past for simplifying the wiring work of electrical components. For example, in Japanese Patent Laid-Open No. 9-317556, an electrical component is assembled in advance to a head cover mounted on a cylinder head, and a wiring circuit for the electrical component is integrally extended on a wall portion of the head cover. In Japanese Patent Laid-Open No. 10-325335, a wire harness connected to a plurality of electric components is built in a unit in the head cover. In Japanese Patent Laid-Open No. 2001-73829, an electrical component and its circuit board are attached on the lower cover body of the head cover, and the upper cover body is attached to the lower cover body so as to cover these electrical components and circuit board.
[0004]
[Problems to be solved by the invention]
Since the inside of the head cover is in an atmosphere of lubricating oil and the outside of the head cover is exposed to water, dust, and the like, a wiring circuit (wire harness) is used as described in JP-A-9-317556 and JP-A-10-325335. In the structure in which the electrical parts are assembled to the head cover with a built-in), it is difficult to ensure the sealing performance of the connection terminals of these electrical parts. If the connection terminal of the electrical component is waterproof, the component unit price is expensive, which increases the cost.
[0005]
The present invention mounts an electrical component and its wiring circuit on a power distribution board unit to form a module, thereby simplifying wiring work and assembly work of the electrical component and ensuring sealing performance around the electrical component without increasing the cost. And it aims at improving the assembly workability | operativity and wiring workability | operativity to the power distribution board unit of an electrical component.
[0006]
[Means for Solving the Problems]
The head cover assembly for an internal combustion engine according to the present invention includes a head cover attached on the cylinder head of the internal combustion engine, and a power distribution plate unit including a unit cover attached in a sealed state on the head cover. On the lower surface side of the unit cover that is opposed to the upper wall of the head cover with a predetermined interval, there are provided a mounting portion to which electrical components are attached in advance and a power distribution board including a wiring circuit for the electrical components. That is, the power distribution board unit is a module in which various electrical components and wiring circuits thereof are mounted on the unit cover and are modularized as one component. The mounting part has a snap-fit fixing structure that can fix the electrical component by inserting the electrical component along the lower surface of the unit cover, and the electrical component is connected to the wiring circuit simultaneously with the fixing. It has come to be. Furthermore, the mounting portion electrically connects the front surface of the electrical component in the insertion direction, a guide means for supporting the electrical component movably along the insertion direction, and the electrical component. And a stopper held at the insertion direction position connected to the connection terminal.
[0007]
Electrical components that are pre-mounted on the power distribution board unit include ignition coils that supply high voltage to the spark plugs, various solenoid valves such as EGR valves for EGR and purge control valves for evaporators, and various sensors such as air-fuel ratio sensors. In addition, a relay, a capacitor, etc. which comprise a wiring circuit are mentioned. Also, functional parts such as a vacuum tank and an oil mist separator may be mounted on the power distribution plate unit by utilizing the gap between these electric parts.
[0008]
【The invention's effect】
According to the present invention, by mounting electrical components and their wiring circuits on the power distribution board unit in advance, the assembly work and wiring work of the individual electrical components are not required during vehicle assembly, and the work efficiency is greatly improved. can do. In addition, since the unit cover of the power distribution board unit is attached to the head cover in a sealed state, it is not necessary to dare to make each connection terminal of the electrical components mounted on the lower surface side of the unit cover waterproof, so the sealing performance is greatly improved. In addition, the cost can be significantly reduced. Furthermore, by inserting the electrical component into the mounting portion, the electrical component can be fixed to the mounting portion, and the electrical component can be connected to the wiring circuit at the same time. Speeded up.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The head cover assembly includes a head cover 10 that is mounted on a cylinder head of an internal combustion engine, and a power distribution plate unit 11 that includes a unit cover 20 that is mounted on the head cover 10 in a sealed state. 1 is a perspective view of the power distribution plate unit 11 as viewed from the lower surface side, FIG. 2 is a perspective view of the head cover 10 alone, and FIG. 3 is a perspective view showing a state in which the power distribution plate unit 11 is assembled to the head cover 10. is there.
[0010]
As shown in FIG. 2, a total of four plug insertion holes 13 are formed in the upper wall 12 of the head cover 10, and rises above the upper wall 12 so as to surround the four sides of the power distribution plate unit 11. A standing wall 14 is formed.
[0011]
As shown in FIG. 1, the unit cover 20 has a flat plate shape whose peripheral edge is attached to the upper edge of the standing wall 14 so as to cover the upper wall 12 of the head cover 10. The power distribution board unit 11 includes a total of four ignition coils 21, two solenoid valves 22, a capacitor 23, as electrical components, on the lower surface 20 a side of the unit cover 20 facing the upper wall 12 of the head cover 10 with a predetermined gap. In addition to the power distribution board 24 on which the wiring circuits of the electrical parts 21, 22, and 23 are printed and wired, functional parts such as a vacuum tank 25 and an oil mist separator 26 to which the solenoid valve 22 is connected are fixed or integrally formed in advance. It is modularized as one part. Such modularization simplifies wiring work and assembling work at the time of vehicle assembly, and can significantly improve work efficiency.
[0012]
The ignition coil 21 supplies a high voltage to the ignition plugs of the corresponding cylinders via the cylinder portions 21a that pass through the plug insertion holes 13 (FIG. 2) of the head cover 10. The solenoid valve 22 controls the negative pressure taken out from the vacuum tank 25. In this embodiment, one of the solenoid valves 22a is an EGR valve and the other 22b is a purge control valve for controlling the evaporator.
[0013]
The power distribution plate 24 is fixed to or integrally formed with the unit cover 20 and is electrically connected to an external engine control unit or the like via a bundle of harnesses 27. This distribution board 24 incorporates a branch circuit contact that can be taken in, and simplifies wiring and lowers costs compared to, for example, a branch circuit contact provided by external wiring.
[0014]
The oil mist separator 26 includes a PCV side chamber 26a connected to a PCV valve of the blow-by gas reduction device and a fresh air side chamber 26b into which fresh air is introduced, and separates the oil mist introduced into each chamber.
[0015]
The vacuum tank 25 and the oil mist separator 26 are formed integrally with the unit cover 20 made of synthetic resin, and are set at substantially the same height so as to fill the gap with the upper wall 12 of the head cover 10. In particular, the vacuum tank 25 is provided at a total of three locations so as to fill the dead space between the adjacent ignition coils 21. Although not shown, a vacuum pipe connected to the vacuum tank 25 is routed inside the unit cover 20, and an inlet / outlet portion 28 of the vacuum pipe protrudes from one side of the unit cover 20.
[0016]
A side wall 29 of the vacuum tank 25 and the oil mist separator 26 stands substantially perpendicularly from the lower surface 20a of the unit cover 20, and a part of the side wall 29 is used to attach a coil mounting portion 30 to which the ignition coil 21 is mounted. And a capacitor mounting portion 31 to which the capacitor 23 is mounted. In other words, the coil mounting portion 30 and the capacitor mounting portion 31 are formed by recessing a part of the functional component structure such as the vacuum tank 25 and the oil mist separator 26 having a high degree of freedom in shape, It increases the degree of aggregation and improves space efficiency.
[0017]
The coil mounting portion 30 has a snap-fit type fixing structure that can be fixed by inserting the ignition coil 21 along the lower surface 20a of the unit cover 20, and electrically connects the ignition coil 21 and the power distribution board 24 simultaneously with the fixing. Thus, the fixing work and the wiring work of the ignition coil 21 are greatly simplified.
[0018]
4 and 5, the coil mounting portion 30 is a pair of guide means that guide and support the ignition coil 21 so as to be movable along the insertion direction along the lower surface 20 a of the unit cover 20. The guide wall 32, the plug portion 33a of the connect terminal 33 that is electrically connected to the front surface 21b in the insertion direction of the ignition coil 21, and the ignition coil 21 are held at the insertion direction position where the ignition coil 21 is connected to the jack portion 33b of the connect terminal 33. And a stopper 34.
[0019]
The guide wall 32 is erected from the lower surface 20 a of the unit cover 20, and the ignition coil 21 is interposed between the first wall portion 32 a facing each other so as to sandwich the ignition coil 21 from both left and right sides, and the lower surface 20 a of the unit cover 20. It has the 2nd wall part 32b bent from the 1st wall part 32a so that it may pinch | interpose up and down. Most of the first wall portion 32 a is formed by the side wall 29 described above. The jack portion 33 b of the connect terminal 33 constitutes a part of the power distribution plate 24 and is disposed on the side wall 29. Note that the plug portion 33 a and the jack portion 33 b of the connect terminal 33 may be provided on either the insertion direction front surface 21 b or the side wall 29 of the ignition coil 21. In this way, a part of the side wall 29 also serves as the guide wall 32, and the jack part 33b (or the plug part 33a) of the connect terminal 33 is provided on a part of the side wall 29. The degree of consolidation is increased and the space efficiency is improved. The stopper 34 is formed so as to protrude from the lower surface 20a of the unit cover 20. The tapered surface 34a gradually increases in the insertion direction, and the stopper surface 34b abutted against the rear surface 21c in the insertion direction of the ignition coil 21. have.
[0020]
As shown in FIG. 5A, when the ignition coil 21 is slid along the guide wall 32, the bottom surface of the ignition coil 21 slides on the tapered surface 34a of the stopper 34, as shown in FIG. As shown, when the ignition coil 21 completely gets over the stopper 34 and the rear surface 21c is abutted against the stopper surface 34b, the plug portion 33a of the connect terminal 33 on the front surface 21b of the ignition coil 21 is inserted into the jack portion 33b. Thus, the connection of the connection terminal 33 is completed, and the stopper 34 prevents the ignition coil 21 from moving in the reverse insertion direction (left direction in FIG. 5), and the ignition coil 21 is fixed.
[0021]
Although not described in detail here, the capacitor mounting portion 31 also has a snap-fit fixing structure that is substantially the same as the coil mounting portion 30. Further, the solenoid valve 22 may have a similar fixing structure.
[0022]
Next, the seal structure and cooling structure of the head cover assembly will be described with reference to FIGS. 6 and 7 are a sectional view and a perspective view corresponding to the head cover, and FIGS. 8 and 9 are a sectional perspective view and a sectional view of the head cover assembly. 6 to 9, the same reference numerals are assigned to substantially the same components as those in FIGS. 1 to 7.
[0023]
As shown in FIGS. 8 and 9, when the power distribution plate unit 11 is assembled to the head cover 10, the gap between the power distribution plate unit 11 and the head cover 10 is sealed by a plurality of gaskets 35, 36, and 37 as seal members. . Specifically, a cover gasket 35 is interposed between the unit cover 20 and the head cover 10, and a coil gasket 36 is provided between the cylinder portion 21 a of the ignition coil 21 and the plug insertion hole 13 of the head cover 10. Intervened. A pipe through hole 39 through which an inlet / outlet pipe 38 integrally formed with the oil mist separator 26 passes is formed in the upper wall 12 of the head cover 10, and a pipe gasket is provided between the inlet / outlet pipe 38 and the pipe through hole 39. 37 is interposed. These gaskets 35 to 37 form a sealed space in which the internal space of the power distribution plate unit 11 is completely sealed. In this sealed space, electrical components such as an ignition coil 21, a solenoid valve 22, and a capacitor 23 are electrical components. And its power distribution board 24 is arrange | positioned. Therefore, it is not necessary to make the connection terminals of these electrical components waterproof, and the component cost can be greatly reduced.
[0024]
The gaskets 35 to 37 can be molded simultaneously with the head cover 10 or the unit cover 20 by, for example, a well-known two-color molding.
[0025]
As shown in FIGS. 6, 7 and 9, a total of three air passages 40 are formed in the head cover 10 below the upper wall 12. As shown in FIGS. 6 and 7, each air passage 40 is opened at both ends of the side wall of the head cover 10 through between the adjacent plug insertion holes 13 (in the structure of FIG. 9, the cylindrical portion 21 a of the ignition coil 21). The head cover 10 is traversed in the width direction toward one side of the opening 41. Further, as shown in FIG. 9, the air passage 40 is formed between the upper wall 12 of the head cover 10 and the sub-upper wall 12a extending below the upper wall. In addition to being able to effectively cool the periphery of the spark plug by flowing the vehicle traveling wind through these air passages 40, the heat trapped in the head cover 10 is radiated from the sub-upper wall 12a, and the head cover 10 is moved from the upper side. While being able to cool effectively, the heat confined in the power distribution board unit 11 is radiated from the upper wall 12, the power distribution board unit 11 can be effectively cooled from the lower side, and the power distribution board unit 11 Heat transfer between the head cover 10 and the head cover 10 can be effectively blocked, and the cooling performance is significantly improved. Such an air passage 40 is not necessarily provided, and is appropriately provided as necessary depending on the output of the internal combustion engine.
[0026]
As described above, the present invention has been described based on specific embodiments. However, the present invention includes various modifications and changes without departing from the scope of the present invention. For example, various sensors as electrical components may be mounted in the distribution board unit.
[Brief description of the drawings]
FIG. 1 is a bottom perspective view showing a power distribution board unit according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a head cover according to an embodiment of the present invention.
FIG. 3 is a perspective view showing an aspect in which the power distribution plate unit is assembled to a head cover.
4 is an enlarged view of a main part of FIG.
FIG. 5 is an explanatory diagram showing a procedure for fixing an ignition coil, where (a) is being inserted, and (b) is a state where insertion has been completed (fixed).
FIG. 6 is a cross-sectional view of the head cover schematically showing a cooling structure of the head cover assembly.
FIG. 7 is a perspective view of a head cover schematically showing a cooling structure of the head cover assembly.
FIG. 8 is a perspective view schematically showing a seal structure of the head cover assembly.
FIG. 9 is a cross-sectional view schematically showing a seal structure and a cooling structure of the head cover assembly.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Head cover 11 ... Power distribution board unit 20 ... Unit cover 21 ... Ignition coil (electric part)
22 ... Solenoid valve 23 ... Capacitor 24 ... Power distribution board 25 ... Vacuum tank 26 ... Oil mist separator 30 ... Coil mounting part 32 ... Guide wall (guide means)
33 ... Connect terminal 34 ... Stopper

Claims (3)

A head cover attached on the cylinder head of the internal combustion engine, and a power distribution plate unit including a unit cover attached in a sealed state on the head cover,
On the lower surface side of the unit cover facing the upper wall of the head cover with a predetermined interval, an attachment part to which electrical components are attached in advance and a power distribution board including a wiring circuit of the electrical components are provided,
By inserting the electrical component into the mounting portion along the lower surface of the unit cover, the electrical component is fixed to the mounting portion, and the electrical component is connected to the wiring circuit .
The mounting part is
A connect terminal that is electrically connected to the front of the electrical component in the insertion direction;
Guide means for supporting the electrical component movably along the insertion direction;
A head cover assembly for an internal combustion engine , comprising: a stopper that holds the electrical component at a position in the insertion direction connected to the connection terminal . 2. The head cover for an internal combustion engine according to claim 1 , further comprising a functional part structure projecting from the lower surface side of the unit cover to the head cover side, wherein the attachment portion is formed by utilizing a side wall of the functional part structure. Assembly. The head cover assembly of the internal combustion engine according to claim 1 or 2 , wherein the electrical component includes a plurality of ignition coils provided for each cylinder of the internal combustion engine.

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