JPS6242152B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention relates to a centrifugal advance device for controlling ignition timing, which is used, for example, in an ignition power distribution device of an internal combustion engine, and in particular to a device capable of stabilizing the advance characteristics thereof. It is.

[Prior art]

FIGS. 1 and 2 show a conventional centrifugal advance device as an example of an ignition power distribution device for an internal combustion engine. In the figure, 1 is a drive shaft, 2 is a base plate fixed to this drive shaft 1, 3 is a pin planted on this base plate 2, 4 is a weight loosely fitted to this pin 3,
Reference numeral 5 denotes an advance angle pin mounted on this weight 4, and 6 an advance angle plate, which is provided with an elongated hole 6a, and this elongated hole 6a is engaged with the advance angle pin 5. An advance angle sleeve 7 is loosely fitted onto the drive shaft 1 and is integrally fixed to the advance angle plate 6. A spring 8 is stretched between spring hooks provided on each of the base plate 2 and the weight 4.

The conventional centrifugal advance device is constructed as described above, and when the entire device rotates with the rotation of the drive shaft 1, the weight 4 receives a flying moment about the pin 3 due to centrifugal force, and the spring 8 The advance angle pin 5, which moves integrally with the weight 4, drives the advance angle plate 6 and the advance angle sleeve 7 integral therewith through the engagement portion with the elongated hole 6a. Advance the angle relative to axis 1. In principle, a relative angular displacement is created from the balance between the centrifugal force generated as a function of the rotational speed and the tension characteristics of the spring, and the advance angle characteristic is shown by the symbol a in Figure 3. is obtained.

However, conventional centrifugal advance devices are mainly based on mechanical principles that respond to centrifugal force, in other words, to respond to the angular velocity of the drive shaft, and do not correspond to the angular acceleration of the drive shaft, and may vary depending on the application. showed very unstable lead angle characteristics. In other words, abnormal jumps in the advance angle as shown by the symbol b in Figure 3, or fluctuations in the advance angle as indicated by the symbol c in the same figure, occur, resulting in engine knocking, changes in exhaust gas concentration, etc. The basic drawback was that it caused problems.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it incorporates a mechanism principle that corresponds to the angular acceleration of the drive shaft, allows the weight support member to fit loosely on the drive shaft, and also allows the weight support member to fit loosely into the drive shaft. To obtain a centrifugal advance device which is easy to assemble and provides stable advance characteristics by constructing a weight and an elastic member that resists the centrifugal force of the weight as a subassembly unit.

[Embodiments of the invention]

FIGS. 4 and 5 show the centrifugal advance device of the present invention as an example of an ignition power distribution device for an internal combustion engine.
In the figure, reference numeral 9 denotes a drive plate fixed to the drive shaft 1 so as to form a plane perpendicular to the axial center of the drive shaft 1, and 9a denotes a drive long groove 10 provided in the drive plate 9 whose axis is centered on the advance sleeve 7. The advance angle plate 10a is fixed to form a plane perpendicular to the advance angle plate 10, and is determined based on the shape of the driving long groove 9a and in correlation with the advance angle characteristics of this device. This is a long groove for advance angle having the shape of . 11 is a weight support member, and a support pin 11
a, an elastic member engaging portion 11b, and a central hole 11c. The weight support member 11 is loosely fitted onto the drive shaft 1 at the center hole 11c. A weight 12 has a supported hole 12a and an elastic member engaging portion 12b. The weight 12 is loosely fitted to the support pin 11a at the supported hole 12a. 13 is the weight 1 above
This rod 13 passes through the weight 12 and has a driving columnar protrusion 13a on one side that is inserted into and engaged with the long driving groove 9a, and on the other side. The above long groove for advance angle 10
A columnar protrusion 13b for advancing angle is formed to be inserted into and engaged with a. Reference numeral 14 denotes an elastic member, which is a tension spring in this example, and is stretched between the elastic member engaging portion 11b and the elastic member engaging portion 12b.

Then, the weight support member 11 and the weight 12
and the elastic member 14 are formed into a subassembly to form a jump unit 15 as shown in FIG.
The drive shaft 1 and the drive side components of the drive plate 9 and the advance angle plate 10 and the advance sleeve side components of the advance angle sleeve 7 are independent.

In the embodiment of the present invention configured as described above,
A major feature is the mechanism for transmitting rotational force from the drive shaft 1 to the weight 12. In other words, in the conventional device, the first
As is clear from the explanation with the figures, the weight 4 receives the rotational force from the drive shaft 1 from the pin 3, and the pin 3 is also the shaft that is blown open by centrifugal force.
However, as can be understood from the explanation with reference to FIG. 4, in the embodiment of the present invention, the weight 2 receives the rotational force from the drive shaft 1 with the drive funnel 13a. Support pin 11a
It is. By the way, in the embodiment of the present invention, as in the conventional device described above, the mechanical principle corresponding to the angular velocity of the drive shaft 1, that is, when it acts only by the centrifugal force of the weight 12, is shown by the broken line a in FIG. It is possible to obtain advanced angle characteristics. This is because pin 3 and advance pin 5 in FIG. 1 correspond to support pin 11a and rod 13 in FIG. 4, respectively, and can be said to be mechanically the same.

Next, the mechanism principle regarding the action when the drive shaft 1 receives angular acceleration will be qualitatively explained. Generally, an abnormality in the advance angle due to angular acceleration in the ignition power distributor of an internal combustion engine is caused by elements connected to the drive transmission path from the drive shaft 1 after the weight 12, that is, the advance angle plate 10, the advance angle sleeve 7, and the elements (not shown). It can be seen that the main influence is the inertial torque generated according to the moment of inertia of the power distribution rotor, etc. 7th
8 and 8 both illustrate the relationship between the forces generated by inertia in the elements constituting the advance angle device when negative angular acceleration occurs on the drive shaft 1. In the conventional device shown in FIG. 7, a force F1 generated by the inertia of an element connected to a stage subsequent to the weight 4 acts on the advance pin 5, and a reaction force R1 from the drive shaft 1 side acts on the pin 3. are doing. For the weight 4, the above force F1 is the reaction force R of the pin 3, which is the jump axis.
The flying torque is applied in proportion to the multiplicative product of the perpendicular line from the point of action of F1 to the line of action of the force F1 with the leg d.
The reaction force R1 has almost no effect on the flying of the weight 4, and at least has no effect on suppressing the flying of the weight 4. In the embodiment according to the invention shown in FIG.
A force F2 generated by the inertia of an element connected to a stage subsequent to the weight 12 acts on the drive shaft 3b, and a reaction force R2 from the drive shaft 1 side acts on the drive columnar projection 13a. In other words, the advance angle long groove 10a and the drive long groove 9a form a wedge in the rod 13, and the jump torque caused by the force F2 on the weight 12 is caused by the point of action of the reaction force R2. This is much smaller than in the case of the conventional device mentioned above in relation to this. Furthermore, due to the frictional force generated between the driving long groove 9a and the driving columnar protrusion 13a due to the reaction force R2, a new fly-opening suppressing torque that is not provided in the above-mentioned conventional device is generated. One of the major features of this new jump suppression torque is that it is due to the friction force that occurs only when responding to angular acceleration, and therefore it prevents hysteresis that deteriorates the quality of the advance angle characteristic that is determined in response to angular velocity. No increase occurs. The reason why the device of the present invention can have the above-described new features is that the weight support member 1
1 is located where it is fitted into the drive shaft 1,
For this purpose, in any case the support pin 11
The point is that no acting force from the drive shaft 1 side can be generated at a. Note that the support pin 11 included in the weight support member 11 in the embodiment of the present invention described above
Even if the shaft and hole fitting relationship between a and the supported hole 12a of the weight 12 are interchanged,
The effects of the present invention are maintained.

Furthermore, considering the jump weight unit 15, although the explanation was limited to a specific direction in FIGS. 4, 5, and 8, if the drive columnar projection 13a and the advance angle columnar projection 13a 13b, the jump weight unit 15 should be completely turned over and the advance angle columnar protrusion 13
Even if the drive columnar protrusion 13a is engaged with the long drive groove 9a and the drive columnar projection 13a is engaged with the advance long groove 10a, the predetermined advance angle characteristics of this device can be achieved without any problem. That is, the jump weight unit 15 can function equally for both clockwise and counterclockwise rotation.

Furthermore, if the driving long groove 9a shown in FIGS. 4 and 8 is formed into a radial shape with respect to the rotating shaft, the driving shaft 1 and the driving plate 9 can be rotated without being limited to the rotating direction. It can be used commonly for both direction and counterclockwise rotation, and can function in exactly the same way.

〔Effect of the invention〕

As described above, according to this invention, by changing the point of application of force to the weight, which is an important element located in the middle of the drive transmission path, the friction force exhibits new and excellent features in terms of mechanical principle. Since it can be constructed so as to cause the angular acceleration of the drive shaft, an excellent centrifugal advance device can be obtained that eliminates the instability of the advance angle with respect to the angular acceleration of the drive shaft, and also allows for easier assembly and common parts during manufacturing. effective.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an outline of the conventional device, Fig. 2 is a side sectional view of the device shown in Fig. 1, Fig. 3 is a characteristic diagram showing advance angle characteristics, and Fig. 4 is an embodiment of the device of the present invention. 5 is a side sectional view of the device shown in FIG. 4, FIG. 6 is a plan view showing a jumping weight unit which is an embodiment of the present invention, and FIG. 7 is a side sectional view of the device shown in FIG.
FIG. 8 is a diagram for explaining the operation of the conventional apparatus shown in the figure, and FIG. 8 is a diagram for explaining the operation of the apparatus of the present invention shown in FIGS. 4 and 5. In the figure, 1 is a drive shaft, 7 is an advance angle sleeve, 9 is a drive plate, 9a is a long groove for driving, 10 is an advance angle plate, 10a is a long groove for advance angle, 11 is a weight support member, 11a, 11b, 11c are respectively a support pin, an elastic member engaging part, a center hole, 12 a weight,
12a and 12b are supported holes and elastic member engaging portions, 13 is a rod, 13a and 13b are a driving columnar projection and an advancing columnar projection, respectively, 14 is an elastic member, and 15 is a flying weight unit. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A centrifugal force is applied to the weight by the rotation of the drive shaft, the weight is made to fly against the elastic force of the elastic member, and the advance sleeve is advanced relative to the drive shaft. In the squaring device, a weight support member is provided that is loosely fitted to the drive shaft, and the weight support member has means for supporting the weight in a freely swingable manner and means for engaging the elastic member, A jumper for a centrifugal angle advance device, characterized in that the weight support member, the weight, and the elastic member are configured as a sub-assembled unit independent of the drive side component and the advance sleeve side component. weight unit. 2. A driving columnar projection that loosely fits onto the drive shaft and engages with a long driving groove of the drive plate, which is a component on the drive shaft side, and a long advance groove on the advance plate, which is a component on the advance sleeve side. 2. The fly-out weight unit for a centrifugal angle advance device according to claim 1, further comprising a columnar protrusion for advancing angle that engages with. 3. The drive columnar projection and the advance angle columnar projection are formed to have the same shape and dimensions, and even if the pairs of the drive long groove and the advance angle long groove that engage with each of these columnar projections are replaced, they will remain the same. The flying weight unit for a centrifugal advance device according to claim 2, wherein the flying weight unit is adapted to function.