JPH07279807A - Ignition distributor for internal combustion engine - Google Patents

Abstract

PURPOSE:To protect a built-in rotation sensor from electromagnetic noise, facilitate the assembly, and simplify the structure. CONSTITUTION:A rotor body 12a mounted on a shaft 4 rotated interlockingly with the cam shaft of an internal combustion engine has an arm electrode 12b for successively distributing the high voltage current supplied from an ignition coil to a plurality of side electrodes 22b connected to the ignition plug of each cylinder according to the rotation of the shaft 4, and a shield cover 12c formed on the lower part of the rotor body 12a integrally with the rotor body 12a. Since the electromagnetic noise generated by the discharge between the arm electrode 12b and the side electrode 22b and directed to a rotation sensor 10 situated on the lower part of a distribution rotor is shielded by the shield cover 12c, the rotation sensor 10 can be operated without being influenced by the electromagnetic noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition distributor for an internal combustion engine having a built-in rotation sensor for detecting the rotation of the internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, an ignition distributor for an internal combustion engine, that is, a distributor 30, is mounted on a shaft 32 which rotates in conjunction with a camshaft of the internal combustion engine. The rotor main body 34 that rotates together with the rotor main body 34 includes an arm electrode 34a that sequentially distributes the high-voltage current supplied from the ignition coil to a plurality of side electrodes 36 that are connected to the spark plugs of each cylinder according to the rotation of the shaft 32. Then, each time the tip of the arm electrode 34 a that rotates around the axis of the shaft 32 approaches the side electrode 36, the arm electrode 3
4a and the side electrode 36 are discharged, a high-voltage current is transmitted to the side electrode 36, and this discharge causes electromagnetic noise.

Further, the distributor 30 detects the rotation of a signal rotor 37 attached to the shaft 32 to detect the rotation of the shaft 32, and outputs a signal for determining the engine speed and the cylinder. A sensor 38 is attached, and the rotation sensor 38 has
A signal processing circuit for outputting the detected signal as a predetermined pulse signal is incorporated. And the arm electrode 3
Electromagnetic noise generated by the discharge between the side electrode 4a and the side electrode 36 may cause the signal processing circuit to malfunction. Therefore, a shield cover made of a conductive material is provided between the rotor body 34 and the signal rotor 37. 40 is arranged, and the shield cover 40 is configured to protect the rotation sensor 38 from electromagnetic noise.

[0004]

However, in this device, the rotor body 34 is assembled so as to rotate together with the shaft 32 by being fixed to the signal rotor 37 fixed to the shaft 32 with the screw 42.
Further, since the shield cover 40 is also assembled between the rotor body 34 and the signal rotor 37 with the same screw 42, it is difficult to align the screw holes and the like, and there is a problem that the assembly takes time.

In order to solve the above problems, the present invention provides
An object of the present invention is to provide an ignition distributor for an internal combustion engine, which can protect the built-in rotation sensor from electromagnetic noise, is easy to assemble, and has a simple structure.

[0006]

An ignition distributor for an internal combustion engine according to claim 1, which is invented to achieve the above object, has a rotating shaft which rotates in conjunction with a camshaft of the internal combustion engine, and the rotating shaft. A plurality of fixed terminals arranged around the shaft and connected to the spark plugs of the respective cylinders, a distribution terminal for distributing the high voltage supplied from the ignition coil to the fixed terminals, and the distribution terminals fixed to the rotary shaft. A rotary unit having a built-in signal processing circuit that detects the rotation of the rotating shaft and generates a pulse signal; a rotor that is disposed between the distribution terminal and the rotation sensor; An ignition distributor for an internal combustion engine, comprising: an electromagnetic shielding plate that shields electromagnetic noise generated between the stationary terminal and the fixed terminal, wherein the electromagnetic shielding plate is formed integrally with the fixing portion. Features .

The ignition distributor for an internal combustion engine according to claim 2 is the ignition distributor for an internal combustion engine according to claim 1.
The electromagnetic shielding plate is insert-molded on the fixed portion of the distribution rotor. The ignition distributor for an internal combustion engine according to claim 3 is the ignition distributor for an internal combustion engine according to claim 1, wherein the electromagnetic shield plate is outsert-molded on a fixed portion of the distribution rotor. Is characterized by.

An ignition distributor for an internal combustion engine according to a fourth aspect is the ignition distributor for an internal combustion engine according to the first aspect,
The electromagnetic shielding plate is a conductive layer laminated on a surface of the distribution rotor.

[0009]

In the ignition distributor for the internal combustion engine according to claim 1 configured as described above, the rotor connected to the rotary shaft that rotates in conjunction with the camshaft of the internal combustion engine has the ignition. The high voltage supplied from the coil is sequentially distributed to the plurality of fixed terminals arranged by the number of cylinders around the rotary shaft through the distribution terminals fixed to the rotor according to the rotation of the rotary shaft.

The distribution terminal and the fixed terminal are not in contact with each other, and each time the distribution terminal, which is fixed to the rotor and rotates about the rotation axis, approaches the fixed terminal, discharge is performed between these terminals. Is distributed to the fixed terminal side. An electromagnetic shielding plate integrally formed with the fixed portion of the rotor so as to be located between the distribution terminal of the rotor and the rotation sensor is generated by the discharge between the distribution terminal and the fixed terminal, and the rotation sensor Shields the electromagnetic noise that goes toward, and protects the rotation sensor with a built-in signal processing circuit from the electromagnetic noise.

As described above, according to the ignition distributor for the internal combustion engine of the first aspect, since the electromagnetic shield plate is located between the rotation sensor and the distribution terminal and the fixed terminal for discharging, the rotation is prevented. The sensor can be protected from electromagnetic noise generated by the electric discharge generated between the power distribution terminal and the fixed terminal, and the rotation of the rotary shaft can be correctly detected.

Further, since the electromagnetic shield plate is formed integrally with the fixed portion of the rotor, the number of constituent parts at the time of assembly is small and the assembly is easy. In the ignition distributor for an internal combustion engine according to claim 2, the electromagnetic shield plate is fixed to the fixed portion by so-called insert molding in which the fixed portion of the rotor is cast while the electromagnetic shield plate is inserted in a predetermined position in advance. It is integrated.

As described above, since the electromagnetic shield plate is integrated at the same time when the fixed portion of the rotor is manufactured, the number of steps can be reduced and the manufacturing is easy. Further, the electromagnetic shielding plate insert-molded on the fixed portion of the rotor is firmly fixed and does not rattle or fall off.

In the ignition distributor for an internal combustion engine according to a third aspect of the present invention, the electromagnetic shield plate is later fitted and fixed to the fixed portion of the rotor which is manufactured in advance so that the electromagnetic shield plate can be fitted in the predetermined position. That is, the electromagnetic shielding plate is integrated with the fixed portion of the rotor by so-called outsert molding.

As a method of fixing the electromagnetic shield plate to the fixed portion of the rotor, for example, when the fixed portion of the rotor is made of thermoplastic resin, the fixed portion of the rotor in which the electromagnetic shield plate is fitted is used. You may heat and fuse, and when the fixed part of the rotor is formed of thermosetting resin etc.,
An adhesive or the like may be used.

Therefore, even in the conventional device, the present invention can be easily applied by forming the electromagnetic shield plate according to the shape of the fixed portion. In the ignition distributor for the internal combustion engine according to the fourth aspect, the electromagnetic shielding plate is formed by laminating the conductive layer on the surface of the distribution rotor.

The conductive layer is formed by vapor deposition of a conductive film,
Since it can be formed by plating, application of a conductive paint, etc., the electromagnetic shield plate can be formed regardless of the shape of the fixed portion of the rotor, and the production is easy. Therefore, it can be easily applied to the rotor of the conventional device.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a distributor to which the present invention is applied. As shown in FIG. 1, the distributor 2 of the present embodiment is for holding a shaft 4 that rotates in conjunction with a camshaft of an internal combustion engine and a shaft 4 so as to be rotatable and to fix the shaft 4 at a predetermined position of the internal combustion engine. Of the housing 6, the signal rotor 8 fixed to the shaft 4, and rotating with the shaft 4, and the hole 8a formed in the signal rotor 8 to detect a pulse signal according to the rotation of the shaft 4. 10 and 1 screw
A distribution rotor 12 fixed to the upper portion of the signal rotor 8 by 6 and rotating together with the shaft 4, and a cap 14 fixed to the housing 6 by a screw 18 and sealing the signal rotor 8, the rotation sensor 10, and the distribution rotor 12. ing.

The power distribution rotor 12 includes a rotor body 12a formed of a non-conductive resin, an arm electrode 12b extending from the center of the rotor body 12a to an edge of the rotor body 12a, and a rotor body 12a. The shield cover 12c is integrally formed on the lower part. The shield cover 12c is in contact with the shaft 4 and is grounded via the shaft 4.

The shield cover 12c is integrated with the rotor body 12a by outsert molding.
That is, the shield cover 12 formed separately from the rotor main body 12a is formed on the rotor main body 12a formed of thermoplastic resin in a shape in which the shield cover 12c can be fitted in advance.
c is fitted and the rotor body 12a is heated to an appropriate temperature so that the rotor body 12a is shielded by the shield cover 12c.
It is fused and integrated into one. The material of the shield cover 12c integrated with the power distribution rotor may be any material as long as it has excellent conductivity, and for example, copper, aluminum or the like can be used.

On the other hand, a center terminal 20 for taking in a high voltage current supplied from an ignition coil (not shown) is provided in the center of the upper portion of the cap 14, and the center terminal 20 is surrounded by the center terminal 20. The secondary line connecting terminals 22 are arranged by the number of cylinders of the internal combustion engine. A center carbon 24 is attached to a lower portion of the center terminal 20 so as to project into the cap 14. The center carbon 24 comes into contact with the rotation center of the arm electrode 12b, so that the center terminal 20 and the arm electrode 12b are separated from each other. Is always on.

The secondary wire connecting terminal 22 is provided with the cap 1
4 has a side electrode 22b protruding inside, and a predetermined gap is provided between the tip of the arm electrode 12b and the side electrode 22b. Next, the rotation sensor 10
Six holes 8 provided in the signal rotor 8 at predetermined intervals
A pulse signal which is composed of a well-known Hall sensor that detects a and a signal processing circuit that outputs the signal detected by the Hall sensor as a predetermined pulse signal, and that is used to represent the engine speed or to identify the cylinder. Is output. And
The pulse signal output from the rotation sensor 10 is taken out of the distributor 2 through the signal line 11 and used to control the operating state of the internal combustion engine.

In the distributor 2 configured as described above, the high voltage current supplied from the ignition coil to the center terminal 20 is supplied to the arm electrode 12b of the rotor via the center carbon 24. Rotor body 1
2a is rotating together with the shaft 4, and accordingly, the tip of the arm electrode 12b passes near the side electrode 22b provided around the power distribution rotor 12 in order. Then, the tip of the arm electrode 12b is the side electrode 22.
When approaching b, a discharge occurs between these electrodes,
A high voltage current is supplied from the arm electrode 12b to the side electrode 22b. This high-voltage current is guided to the spark plug (not shown) of each cylinder by the high withstand voltage cord connected to the secondary line connecting terminal 22.

The arm electrode 12b and the side electrode 22
Electromagnetic noise is generated when discharge is performed between b and
Shield cover 12c integrated with distribution rotor 12
However, it blocks electromagnetic noise directed downward in FIG. 1, that is, in the direction in which the rotation sensor 10 is arranged.

As described above, according to the distributor 2 of this embodiment, the shield cover 12c formed integrally with the rotor body 12a is generated between the arm electrode 12b of the power distribution rotor 12 and each side electrode 22b. do it,
Since the electromagnetic noise directed in the direction in which the rotation sensor 10 is arranged is blocked, the rotation sensor 10 can correctly output the pulse signal according to the rotation of the shaft 4 without being affected by the electromagnetic noise.

Since the shield cover 12c is formed integrally with the rotor body 12a in advance, when the distributor 2 is assembled, only the distribution rotor 12 is assembled, and the shield cover 12c is assembled at the same time. The shield cover 12c is formed separately from the rotor body 12a, and the number of assembling steps can be reduced and the assembling can be facilitated, as compared with the conventional device in which these must be assembled separately. Further, since the number of parts is reduced, it becomes easy to store and manage the parts.

Further, since the shield cover 12c is integrated with the rotor body 12a by outsert molding, it can be easily applied even to a conventional device. In the outsert molding in this embodiment, since the rotor body 12a is formed of a thermoplastic resin, a method of heating the rotor body 12a to fuse it to the shield cover 12c is used. When they are formed of a thermosetting resin, they may be integrated by using an adhesive or the like.

Further, in this embodiment, the shield cover 12
Although outsert molding is performed to integrate c with the rotor body 12a, they may be integrated by insert molding. That is, the rotor body 12
When casting a, the shield cover 12c is integrally molded with the rotor body 12a by pouring resin into the mold with the shield cover 12c inserted in advance at a predetermined position of the mold for producing the rotor body 12a. To do. In this case, a thermosetting resin such as epoxy or phenol can be used as the material of the rotor body 12a.

In the distribution rotor 12 in which the shield cover 12c is integrated by insert molding, the shield cover 12c does not fall off from the rotor body 12a unless the rotor body 12a is destroyed. Further, since the shield cover 12c and the rotor body 12a are integrated at the same time when the rotor body 12a is manufactured, the number of manufacturing steps can be reduced and the manufacturing is easy.

Instead of outsert molding or insert molding the shield cover 12c on the rotor body 12a, as shown in FIG. 2, the lower surface of the rotor body 12a (the surface facing the signal rotor 8 and the rotation sensor 10).
Alternatively, the conductive layer 12d may be formed. The conductive layer 12d
Can be formed by vapor deposition of a conductive film, plating, application of a conductive paint, or the like.

The distribution rotor 12 having the conductive layer 12d has a simple structure because it does not need to use a shield cover because the conductive layer 12d blocks electromagnetic noise similarly to the shield cover. Further, in order to form the conductive layer 12d of the rotor body 12a, it is sufficient to apply, for example, a conductive paint, so that the conventional device can be easily applied.

Further, the electromagnetic noise can be shielded only by forming a conductive layer on the rotor body of the conventional apparatus. Further, like the conventional apparatus, a shield cover provided separately from the rotor body is used. May be attached. In this case, a double electromagnetic shield layer is formed by the conductive layer and the shield cover, and electromagnetic noise can be shielded more effectively.

2B is a bottom view of the rotor main body 12a on which the conductive layer 12d is formed, and FIG.
It is a -Y sectional view. In addition, the cross-sectional views of FIG. 1 and FIG.
It is sectional drawing at the time of cutting the whole distributor along the XZ cross section in FIG.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be implemented in various modes without departing from the scope of the present invention. For example, although the rotation sensor 10 uses a Hall sensor in the present embodiment, it may be any one that includes a signal processing circuit inside, and may irradiate the signal rotor with light and detect its transmitted light or reflected light. By doing so, the rotation state of the signal rotor may be detected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a distributor of this embodiment.

FIG. 2 is an explanatory diagram showing a state of a conductive layer formed on a power distribution rotor 12.

FIG. 3 is a cross-sectional view showing a configuration of a conventional distributor.

[Explanation of symbols]

2 ... Distributor 4 ... Shaft 6
... Housing 8 ... Signal rotor 10 ... Rotation sensor 11
... signal line 12 ... power distribution rotor 12a ... rotor body 1
2b ... Arm electrode 12c ... Shield cover 12d ... Conductive layer 1
4 ... Cap 20 ... Center terminal 22 ... Secondary wire connection terminal 2
2b ... side electrode 24 ... center carbon

Claims (4)

[Claims] 1. A rotary shaft that rotates in conjunction with a camshaft of an internal combustion engine, a plurality of fixed terminals arranged around the rotary shaft and connected to a spark plug of each cylinder, and supplied from an ignition coil. A rotor comprising a distribution terminal for distributing a high voltage to the fixed terminal, a fixed portion for fixing the distribution terminal to the rotary shaft, and a signal processing circuit for detecting a rotation of the rotary shaft and generating a pulse signal are incorporated. An ignition distributor for an internal combustion engine, comprising: a rotation sensor; and an electromagnetic shield plate that is arranged between the distribution terminal and the rotation sensor and shields electromagnetic noise generated between the distribution terminal and the fixed terminal. The ignition shield for an internal combustion engine, wherein the electromagnetic shielding plate is formed integrally with the fixing portion. 2. The ignition distributor for an internal combustion engine according to claim 1, wherein the electromagnetic shield plate is insert-molded in a fixed portion of the distribution rotor. 3. The ignition distributor for an internal combustion engine according to claim 1, wherein the electromagnetic shield plate is outsert-molded on a fixed portion of the distribution rotor. 4. The electromagnetic shield plate is a conductive layer laminated on a surface of the power distribution rotor.
An ignition distributor for an internal combustion engine according to item 1.