JPS636742B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an engine ignition timing control device that controls the ignition timing of an engine in accordance with the rotational speed of the engine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS This type of engine ignition timing control device, which has been generally known in the past, will be explained with reference to FIGS. 1 to 3. In the figure, 1 is a housing fixed to an engine (not shown, the same applies hereinafter), 2 is a bearing metal press-fitted into this housing 1, and 3 is rotatably supported by this bearing metal 2 and driven by the engine. Axis of rotation,
4 is a governor plate fixed to the rotating shaft; 5
is a pair of pins erected on this governor plate 4, 6 is a pair of governor weights loosely fitted to this pin 5, 7 is a spring hook fixed to the governor plate 4, and 8 is the governor weight 6 and the above spring. A spring is stretched between the hanger 7, a pin 9 is protruded from the side of the governor weight 6 opposite to the governor plate 4, and 10 has an elongated hole 10a into which the pin 9 is loosely fitted. The cam base 11 is fixed to the lower end of the cam 11 in FIG.
A cylindrical cam 12 is rotatably fitted loosely into the rotary shaft 3, and a washer 14 is fixed to the upper end of the rotating shaft 3 in FIG. 1 is a fixed plate formed into a substantially disk shape surrounding the cam 11 and fixed to the housing 1; 15 is a movable plate rotatably supported by the fixed plate 14; and 16 is attached to the movable plate 15. , is a conventionally well-known interrupter that constitutes an ignition timing determining member, and contacts 16a are opened and closed by the rotation of the cam 11, and an ignition coil (not shown) is connected.
The primary current is intermittent. Reference numeral 17 denotes a power distribution cap that closes an opening at one end of the housing 1.

In the configuration as described above, when the rotating shaft 3 is rotated by the engine, the cam 11 is rotated via the governor plate 4, pin 5, governor weight 6, spring 8, pin 9, and cam base 10. Therefore, the contact 16a of the interrupter 16 opens and closes, and the primary current of the ignition coil (not shown) is interrupted. Here, to explain the control operation of the ignition timing according to the engine speed, when the engine speed is below a predetermined value, the governor weight 6 is biased by the spring 8, so the cam base 10 is That is, the position of the cam 11 is at the position shown in FIG. 3A. Next, when the rotational speed of the engine increases, the centrifugal force of the governor weight 6 increases in accordance with the rotational speed. It flies to the position where the tension is balanced. Therefore, as shown in FIG. 3B, the cam 11 rotates relative to the rotating shaft 3. For example, if the rotating direction of the rotating shaft 3 is in the direction of arrow A,
The opening/closing operation of the interrupter 16 will be more advanced than when it is positioned as shown in FIG. 3A.

Incidentally, an engine operates continuously by repeating the four strokes of explosion, exhaust, intake, and compression.In the three strokes of exhaust, intake, and compression, the engine receives a large amount of energy from the explosion and due to its inertia. For example, the angular acceleration differs significantly between the compression stroke and the explosion stroke. As a result, the angular acceleration of the rotating shaft 3 connected to the engine fluctuates rapidly in the same way as the engine, and furthermore, the advance angle characteristics become extremely unstable due to the inertia of the advance mechanism such as the governor weight 8 and cam 11. On the other hand, since the advance mechanism is constituted by a rotating body, there is a drawback that the bearing portion, sliding portion, etc. are easily worn out due to rotational vibration, resulting in a lack of durability.

This invention was made to eliminate the drawbacks of conventional devices as described above, and the purpose is to provide an engine ignition timing control device that provides stable advance angle characteristics and is highly durable. .

An embodiment of this invention will be described below with reference to FIGS. 4 to 8. In the figure, 11 is a cam fixed to the rotating shaft 3, 14 is a fixed plate formed in the shape of a disk as in the conventional case, and a bearing 1 is attached to the inner periphery.
4a. 15a is an arcuate long hole provided in the movable plate 15, 18 is a cylindrical drive member fixed to the rotating shaft 3, and 18a is a permanent magnet installed near the outer periphery of the drive member 18. A plurality of N poles and S poles are arranged alternately, and generate a magnetic flux that interlinks with a conductor 19a, which will be described later. Reference numeral 19 denotes a driven member made of a two-stage cylindrical magnetic material with one end having a larger diameter than the other end. It is rotatably supported on the rotating shaft 1 via a bearing 20 fitted to the inner periphery of the cylindrical portion. Reference numeral 19a denotes a conductor provided inside the inner periphery of the cylindrical portion at one end of the driven member 19, and the drive member 18 and the driven member 19 constitute a sliding connection means. 21 is an external gear fixed to the other end of the driven member 19, 22 is a gear shaft fixed to the fixed plate 14, and 23 is a gear loosely fitted to the gear shaft 22 and meshed with the external gear 21. There is. Reference numeral 24 denotes an inner gear having the movable plate 15 fixed to its outer periphery at one end, and is fitted into the bearing 14a and rotatably supported, and meshes with the gear 23. Note that the outer gear 21, gear 23, and inner gear 24 constitute a rotating means. Reference numeral 25 denotes a spindle erected on the fixing plate 14, and the long hole 1
5a. Reference numeral 26 denotes a spring hook erected on the movable plate 15, and 27 a spring stretched between the spindle 25 and the spring hook 26. Descriptions of other symbols are omitted as they are the same as those of the conventional device.

In the apparatus configured as described above, the ignition timing control operation according to the engine speed will be explained. When the rotary shaft 3 is rotated by the engine and the drive member 18 and the driven member 19 rotate relative to each other, the interlinkage magnetic flux of the conductor 19 changes, and a secondary current I is generated in the conductor 19a due to electromagnetic induction.
Torque is transmitted to the driven member 19 by the electromagnetic action of the magnetic field caused by this secondary current I and the magnetic field caused by the permanent magnet 18a, and this torque is transmitted to the outer gear 2.
1, the gear 23, and the inner gear 24 in the direction of the arrow in FIG. Here, movable plate 1
The torque transmitted to the drive member 5 increases depending on the relative rotation speed between the drive member 18 and the driven member 19, that is, the rotation speed of the rotation shaft 3. First, when the rotation speed of the rotation shaft 3 is below a predetermined value, The position of the movable plate 15, that is, the position of the interrupter 16 is at the position shown in FIG. 5 due to the tension of the spring 27.
Next, when the rotational speed of the engine increases, the torque transmitted to the movable plate 15 also increases as described above, and the movable plate 15, that is, the interrupter 16 resists the tension of the spring 27 to rotate the cam 11. It is rotated in the opposite direction to advance the ignition timing. Note that the maximum advance angle amount in this case is determined by the spindle 25 coming into contact with the elongated hole portion 15a. Further, as described above, the torque transmitted to the movable plate 15 is determined by the rotational speed of the rotating shaft 3, but the angular acceleration of the rotating shaft 3 fluctuates rapidly as in the conventional device. However, the angular acceleration of the drive member 18 fixed to the rotating shaft 3
Even if there is a sudden change in the same way, the driven member 19
Due to its inertia, it does not follow sudden fluctuations in angular acceleration of the drive member 18 and generates stable torque.

9 and 10 show another embodiment of this invention, in which 28 is a drive member fixed to the rotating shaft 3 and has a fan 28a on the outer periphery, and 29 is a drive member that connects the drive member 28 with a gap. The driven member is disposed so as to surround the drive member, and is rotatably supported on the rotating shaft 3 by a bearing 29a provided on the inner periphery. 29a is a fan provided on the inner periphery of the driven member 29 so as to face the fan 28a of the drive member 28; 30 is a seal ring 31 provided in the gap between the drive member 28 and the driven member 29;
A viscous fluid, such as oil, sealed by Note that the drive member 28, the driven member 29, the oil 30, and the seal ring 31 constitute a sliding connection means. In this configuration, the rotation of the rotating shaft 3, that is, the rotation of the drive member 28, causes
The oil 30 rotates and causes the driven member 29 to generate torque.

Further, in the above description, the cam 11 is attached to the rotating shaft 3, but the cam 11 may be formed integrally with the rotating shaft 3, and this configuration has the effect of reducing the number of parts. .

As described above, the present invention connects the rotating shaft and the ignition timing determining member via the sliding connecting means, and the ignition timing determining member is connected by the torque generated in the sliding connecting means according to the rotational speed of the rotating shaft. Since the ignition timing is controlled by rotating the ignition timing, the effects of sudden changes in the angular acceleration of the rotating shaft and the effects of the inertia of the advance mechanism can be minimized, and stable advance angle characteristics can be obtained. The corner mechanism is less susceptible to rotational vibration, which has the effect of improving durability.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional front view showing a conventional device, Fig. 2 is a plan view showing the ignition timing determining mechanism of the conventional device, and Fig. 3 is a plan view showing the ignition timing determining mechanism of the conventional device.
The figures show a centrifugal advance mechanism of a conventional device, with FIG. 3A being a plan view showing before advance, and FIG. 3B being a plan view showing full advance. Fig. 4 is a cross-sectional front view showing an embodiment of this invention, Fig. 5 is a plan view showing an ignition timing determining mechanism of an embodiment of this invention, and Fig. 6 is a sectional plane showing an embodiment of this invention. 7 is a developed view of the outer periphery of a drive member showing an embodiment of this invention, FIG. 8 is a developed view of the side inner periphery of a driven member showing an embodiment of this invention, and FIG. FIG. 10 is a partially sectional front view showing this embodiment, and FIG. 10 is a sectional plan view showing another embodiment of this invention. In the figure, 3 is a rotating shaft, 11 is a cam, 15 is a movable plate, 16 is an interrupter, 18 is a drive member, 19 is a driven member, 21 is an external gear, 2
3 is a gear, 24 is an inner gear, 25 is a spindle, 2
6 is a spring hook, and 27 is a spring. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A rotating shaft that rotates in synchronization with the rotation of the engine, an ignition timing determining member that determines the ignition timing according to the rotation of the rotating shaft, and this ignition timing determining member being installed,
A movable plate rotatably provided around the rotational shaft, a sliding connection means that is slidingly connected to the rotational shaft and generates a torque according to the rotational speed of the rotational shaft, and a torque of the sliding connection means. An engine ignition timing control device comprising a rotating means for rotating the movable plate in accordance with the engine ignition timing control device. 2. The sliding coupling means includes a drive member which is fixed to a rotating shaft and has a permanent magnet therein, and a drive which is rotatably supported on the rotating shaft so as to surround this drive member and is made of a magnetic material and has a conductor inside. An engine ignition timing control device according to claim 1, characterized in that the engine ignition timing control device is comprised of a member. 3. The sliding coupling means includes a drive member fixed to a rotating shaft and having a fan on its outer periphery, and a fan that is rotatably supported on the rotating shaft so as to surround the drive member with a gap therebetween and faces the fan. and a viscous fluid sealed in a gap between the drive member and the driven member. .