JPH07101026B2 - Governor advance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a governor advance device, and more particularly, to a structure of a governor advance device incorporated in a vehicle power distributor to adjust the ignition timing of an engine. In particular, the present invention relates to a governor advance angle device suitable for a large engine angular acceleration.

<Prior Art> In an engine power distributor, as the engine speed increases, the rotation angle of the crankshaft that rotates within a certain combustion time also increases, so it is necessary to advance the engine ignition timing accordingly. The governor advance device is used for that purpose.

FIG. 11 is a diagram showing the structure of a governor advancement device that has been conventionally used in a distributor of an automobile engine. In FIG. 11, 1 is a drive shaft, 2 is a base plate fixed to the drive shaft 1, and a weight support shaft 3 and a spring rod 4 are fixed to the base plate 2, respectively. 5 is a weight,
A drive pin 6 and a spring hooking pin 7 are planted at one end of the weight 5, respectively. A timing lever 8 is integral with the rotor shaft 9, and the timing lever 8 is provided with a cam groove 10 at a symmetrical position with respect to the rotor shaft 9. The rotor shaft 9 is
It is rotatably attached to the drive shaft 1. In the figure,
Reference numeral 11 denotes a tension spring which is an example of an elastic member.

The conventional governor advance device is configured as described above,
When the drive shaft 1 rotates and the entire device rotates, the weight 5 receives a moment due to a centrifugal force that attempts to cause the weight 5 to fly outward with the weight support shaft 3 as the center, and elastic force of the tension spring 11 causes the weight 5 to rotate. Fly to a position that balances the moment. During the process in which the weight 5 is opened, the drive pin 6 planted in the weight 5 is
Through the contact point between the drive pin 6 and the cam groove 10, the timing lever 8 and the rotor shaft 9 formed integrally with the timing lever 8 are advanced relative to the drive shaft 1. As described above, the governor advancement device determines the relative relationship between the drive shaft 1 and the rotor shaft 9 based on the balance between the centrifugal force determined by the rotational speed (angular velocity) of the drive shaft 1 and the elastic force characteristic of the tension spring 11. It creates a lead angle. Thirteenth
The curve indicated by a in the figure represents an example of the advance angle characteristic determined as described above.

However, the advance characteristic of the conventional governor advance device is the magnitude of the centrifugal force generated in the weight 5 as described above, in other words,
The design is such that it is determined only by the magnitude of the rotational speed of the drive shaft 1, and the influence of the angular acceleration of the drive shaft 1 has not been considered so much. For this reason, in an engine or the like in which the change in the angular acceleration that occurs in synchronization with combustion is large, a very unstable advance characteristic appears due to the inertial force generated in the weight 5 and the timing lever 8 due to the angular acceleration. was there. That is, the inertial force Fw generated on the weight 5 acts on the center of gravity 12 of the weight 5,
As shown in FIG. 12, when the angular acceleration of the drive shaft 1 is negative, that is, when decelerating, a moment Fw · e that causes the weight 5 to fly further outward from the balance position is generated, and conversely, the angular acceleration of the drive shaft 1 is increased. Is positive, that is, at the time of acceleration, a moment −Fw · e is generated to return the weight 5 from the balanced position to the inside. Also, as shown in FIG. 12, the timing lever 8 (the moment of inertia about the drive shaft 1 is It) has a negative angular acceleration of the drive shaft 1 (negative α), that is, It. A moment α is generated, and this moment tries to cause the weight 5 to fly further outward from the balanced position through the contact point between the cam groove 10 and the drive pin 6, and conversely, the angular acceleration of the drive shaft 1 is positive (α That is, a moment of −It · α is generated during acceleration, and this moment tries to return the weight 5 from the balanced position to the inside.

Generally, the engine is ignited during its compression stroke, that is, when the angular acceleration of the drive shaft 1 is negative, and as described above, the weight 5 flies further outward from the original balance position, and the 13th A phenomenon such as the advance of the advance angle shown by the curve of b in the figure occurred, which brought about a bad symptom such as knocking in the engine. Further, such an advance jump phenomenon has a bad influence particularly when the rotation speed (angular speed) of the drive shaft 1 is small, that is, when the advance angle is small, as can be seen from FIG.

As a measure for preventing the advance jump of the conventional governor advance device, for example, there is a device described in Japanese Utility Model Laid-Open No. 61-41865.

<Problems to be Solved by the Invention> However, in the above-described conventional technique, it is necessary to newly provide a member called a stabilizing wheel in the configuration of the governor advancement device, and the inertia force that attempts to open the weight. Since the moment is generated as before, it is intended to cancel this moment by the opposite moment generated by the stabilizing wheel, so that the drive pins implanted in the weight are subjected to large opposite forces. It cannot be said that sufficient consideration has been given to problems such as promoting wear and deformation of the drive pin or the cam groove of the timing lever that comes into contact with the drive pin and the elongated hole provided in the stabilizer wheel.

An object of the present invention is to solve such a problem and to provide a governor advance device that can obtain stable advance characteristics regardless of changes in the angular acceleration of the drive shaft.

<Means for Solving the Problems> In order to achieve such an object, the present invention provides a weight that flies outward by a centrifugal force generated by the rotation of a drive shaft, and an elastic member that applies an elastic force that returns the weight to the inside. A governor provided with a drive pin for advancing provided on the weight, a timing lever engaged with the drive pin, and a rotor shaft advanced relative to the drive shaft via the timing lever. In the advance device, the position of the center of gravity of the weight is set so that the inertial force generated in the weight due to the negative angular acceleration of the drive shaft becomes a moment for returning the weight inward, and the weight lever is provided in the timing lever. The cam groove is shaped so that the fly position of the weight does not change due to the inertial force generated in the timing lever due to the angular acceleration of the drive shaft. A stable advance angle characteristic is obtained regardless of the change in the angular acceleration of the shaft.

<Action> Since the inertial force that causes the weight due to the negative angular acceleration of the drive shaft becomes a moment in the direction of returning the weight to the inside, it is possible to prevent the weight from further popping out from the balanced position. Since the fly position of the weight does not change depending on the inertial force generated in the timing lever due to the angular acceleration of the drive shaft, there is no harmful phenomenon such as jumping of the advance angle due to the change in the angular acceleration of the drive shaft. Stable advance angle characteristics can be obtained.

<Example> Hereinafter, an example of the present invention is described based on a drawing.

FIG. 1 is a plan view showing an entire groove of a governor advancement device according to the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. In the figure, the names of the members indicated by the reference numerals 1 to 12 are exactly the same as those of the conventional governor advance device shown in FIG.

However, in the governor advancement apparatus of this embodiment, the position of the center of gravity 12 of the weight 5 is determined as described below. That is, in FIG. 3, a tangent line extending from the center of gravity 12 on an arc passing through the center of gravity 12 centered on the drive shaft 1 toward the weight support shaft 3 and the line segment connecting the center of gravity 12 and the weight support shaft 3 are driven. Position of the center of gravity 12 so as to be located between the rotation centers of the shaft 1,
In other words, a tangent line extending from the center of gravity 12 on an arc passing through the center of gravity 12 around the drive shaft 1 toward the weight support shaft 3 connects the weight support shaft 3 and the rotation center of the drive shaft 1 to each other. The shape of the weight 5 and the position of the weight support shaft 3 are determined so as to intersect the position. When the position of the center of gravity 12 is determined in this way, the moment Fw · e generated about the weight support shaft 3 by the inertial force Fw generated on the weight 5 by the negative angular acceleration of the drive shaft 1 causes the weight 5 to move inward. I try to get it back.

On the other hand, the shape of the cam groove 10 provided in the timing lever 8 is determined as described below. That is, the fourth
In FIGS. 5, 5, 6 and 7, the angle θw formed by the common normal line at the contact point between the drive pin 6 and the cam groove 10 and the moving direction of the weight 5 is large, and conversely, the drive pin 6 and Cam groove
The angle θt formed by the common normal line at the 10 contact points and the movement direction of the timing lever 8 is determined to be small.

When the frictional force between the drive pin 6 and the cam groove 10 does not act, that is, when the friction coefficient μ between the drive pin 6 and the cam groove 10 is 0 (in the case of driving the weight, FIG. 4, timing lever). 5) in the case of driving the gear, the force F exchanged between the weight 5 and the timing lever 8 is the drive pin 6
Is equal to the normal force N acting in the direction of the common normal at the contact point between the cam groove 10 and the cam groove 10. At this time, of the normal force N, the magnitude of the force effectively used by the timing lever 8 to move the weight 5 is N · cos θw. Similarly, of the normal force N, the magnitude of the force effectively used by the weight 5 to move the timing lever 8 is N · cos θt.

Next, a case where a frictional force acts between the drive pin 6 and the cam groove 10 will be described (the case where the weight is driven is the sixth case).
(Fig. 7, the case of driving the timing lever). The force F exchanged between the weight 5 and the timing lever 8 is the normal force N acting in the direction of the common normal at the contact point between the drive pin 6 and the cam groove 10 and the force between the drive pin 6 and the cam groove 10. Is the resultant force of frictional force μN, and its magnitude is F = N (1+
is a μ ^{2) 1/2.}

Now, the angle formed by the resultant force F and the movement direction of the weight 5 is φ
w, and an angle formed by the resultant force F and the movement direction of the timing lever 8 is φt, then φw = θw + tan ⁻¹ μ, θt = θt
+ Tan ⁻¹ μ, and there are relationships of φw> θw and φt> θt. Therefore, of the resultant force F, the magnitude F of the force effectively used by the timing lever 8 to move the weight 5
cosφw is F · cosφw <N · cosθw. Similarly, of the resultant force F, the magnitude of the force F · cosφ effectively used by the weight 5 to move the timing lever 8.
t is F · cosφt <N · cosθt. In other words, F
The magnitude of cosφw, F · cosφt becomes smaller as the friction coefficient μ increases, and finally, when φw, φt reaches 90 °, the value becomes zero.

The above considerations regarding the shape of the cam groove 10 will be summarized. The function that the governor advance device should originally have, that is, the advance characteristic of the governor advance device is determined only by the magnitude of the centrifugal force generated in the weight 5, in other words, the magnitude of the rotational speed of the drive shaft 1. Considering that it should be, the drive pin 6 must be able to easily drive the timing lever 8 by the centrifugal force generated in the weight 5, and the drive pin 6 or the weight 5 can be driven by the inertial force generated in the timing lever 8. It should not be easily driven.
The shape of the cam groove 10 that satisfies these conditions means that the force F and the movement direction of the timing lever 8 are set so that the driving pin 6 keeps a large force F · cosφt effective for driving the timing lever 8. The angle φt = θt + tan ^-1 μ
Is as small as possible, that is, θt is as small as possible, and conversely, in order to keep the force F · cosφw effective for driving the drive pin 6 by the timing lever 8, the angle φw formed by the resultant force F and the movement direction of the weight 5 is kept. = Θw + tan ⁻¹ μ is as large as possible, that is, θw is as large as possible. Further, as can be seen from FIG. 13, the phenomenon in which the advance angle jumps up is particularly remarkable when the rotational speed (angular speed) of the drive shaft 1 is small, that is, when the advance angle is small, so that the cam groove in the small advance angle portion is large. In the shape of 10, the angle θw formed by the common normal line at the contact point between the drive pin 6 and the cam groove 10 and the movement direction of the weight 5 is particularly large.

All of the above considerations regarding the shape of the cam groove 10 were qualitative. Here, it is desired to more quantitatively grasp the shape of the cam groove 10.

As described above, the shape of the cam groove 10 is such that the driving pin 6 keeps a large force F · cosφt effective for driving the timing lever 8 so that the resultant force F and the movement direction of the timing lever 8 form an angle φt = θt + tan ⁻¹ μ is as small as possible, that is, θt is as small as possible, and conversely, the effective force F · cos for the timing lever 8 to drive the drive pin 6 is
In order to keep φw small, the angle φw = θw + tan ⁻¹ μ formed by the resultant force F and the movement direction of the weight 5 is determined to be as large as possible, that is, θw is determined to be as large as possible. Reconsider this condition more severely, and check the cam groove 10 and drive pin 6
When μmax is the maximum friction coefficient between the two, which is considered in design, the necessary condition for the drive pin 6 to drive the timing lever 8 is cosφt> 0, that is, φt <90 °. From this relationship, when the range of the angle θt formed by the common normal line at the contact point between the drive pin 6 and the cam groove 10 and the movement direction of the timing lever 8 when the maximum friction coefficient is μmax is calculated, φt = θt + tan ^{− 1}
μmax <90 °, that is, θt <90 ° −tan ⁻¹ μmax.
On the other hand, depending on the timing lever 8, the drive pin 6 or the weight 5 is absolutely required to be moved by cos.
φw <0, that is, φt> 90 °. From this relationship,
When the range of the angle θw formed by the common normal line at the contact point between the drive pin 6 and the cam groove 10 and the moving direction of the weight 5 when the maximum friction coefficient is μmax is calculated, φw = θw +
tan ⁻¹ μax> 90 °, that is, θw> 90 ° −tan ⁻¹ μmax. The maximum friction coefficient μmax and θt and θ described above
The range that w can take is summarized in a graph and shown in FIG.

9 and 10 are views showing θt and θw, respectively, when the cam groove 10 of the present embodiment is advanced. In FIG. 9, the magnitude of θt is approximately −30 ° <θ
It is extremely small at t <30 °, and the magnitude of θw is large at 30 ° <θw <90 ° in FIG. Further, in FIG. 10, θw has a particularly large value near 90 ° in the range of the small advance angle where the jump of the advance angle easily occurs.

The shapes of the cam grooves shown in FIGS. 1, 9 and 10 are merely examples of the present invention, and various advance characteristics can be obtained by using the concept disclosed in the present invention. With the governor lead angle device that it has, safe lead angle characteristics can be obtained regardless of changes in the angular acceleration of the drive shaft.

FIG. 14 is an overall configuration diagram of an automatic engine power distributor including the governor advancement device of the present invention. In FIG. 14, a joint 14 of a negative pressure responding device (not shown) attached to the distributor housing 13 is a fixed base fixed to the housing 13.
It is connected to a movable base 16 that is rotatably loosely fitted to 15. A magnet 17 and a stator core 18 are mounted on the movable base 16, and an ignition timing control device 20 having a detection coil 19 is mounted on the fixed base 15.
On the other hand, the reluctor 21 is integrated with the rotor shaft 9 loosely fitted to the drive shaft 1 driven by the engine. Therefore, the rotation causes the stator core 18 and the reluctor 21 to rotate.
When the space between and changes, magnet 17 and stator core 1
8, the amount of magnetic flux having the reluctor 21, rotor shaft 9, and movable base 16 as magnetic paths changes, and a voltage is generated in the detection coil 19, and the ignition timing device 20 operates with this signal voltage to determine the ignition timing. .

This signal voltage is the negative pressure responsive device (not shown) described above,
The generation timing is changed by the governor advancement device of the present invention, which is composed of the weight 5 attached to the base plate 2 integrated with the drive shaft 1, the tension spring 11, the rotor shaft 9 and the body timing lever 8. It is well known that the ignition timing is determined.

In the distributor having such a configuration, the governor advancement device of the present invention can obtain stable advancement characteristics regardless of changes in the rotational acceleration of the engine, that is, changes in the angular acceleration of the drive shaft 1. Thus, the ignition timing is stably determined, and good ignition can be realized for combustion of the air-fuel mixture in the engine.

<Effects of the Invention> As described above, according to the present invention, the inertial force generated in the weight due to the negative angular acceleration of the drive shaft becomes a moment for returning the weight to the inner side, and the angular acceleration of the drive shaft is reduced. Therefore, the fly position of the weight does not change depending on the inertial force generated in the timing lever.Therefore, stable advance characteristics can be obtained without causing harmful phenomena such as jumping of the advance angle due to changes in the angular acceleration of the drive shaft. To be

[Brief description of drawings]

FIG. 1 is a plan view showing the overall configuration of a governor advancement apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, FIG. 3, FIG. 4, and FIG. FIG. 6, FIG. 7 and FIG. 7 are diagrams for explaining the force acting on the governor advance device, and FIG. 8 is a diagram showing the relationship between the maximum friction coefficient μmax and the possible range of θt and θw. 9 and 10 are views showing θt and θw at each advancing angle of the cam groove of this embodiment, and FIG. 11 is a view showing the structure of a conventional governor advancing device. FIG. 13 is a diagram for explaining a force acting on a conventional governor advance angle device, FIG. 13 is a diagram showing an example of an advance angle characteristic, and FIG. 14 is an automobile equipped with the governor advance angle device of the present invention. It is a whole block diagram of the engine distributor. Explanation of symbols 1 ... Drive shaft, 3 ... Weight support shaft, 5 ... Weight,
6 ... drive pin, 8 ... timing lever, 9 ... rotor shaft, 10 ... cam groove, 11 ... tension spring

Claims (5)

[Claims] 1. A weight that opens outward by a centrifugal force generated by the rotation of a drive shaft, an elastic member that gives an elastic force that returns the weight to the inside, a drive pin for advancing the angle provided on the weight, and the drive. In a governor advance device including a timing lever engaged with a pin and a rotor shaft advanced relative to the drive shaft via the timing lever, a cam groove provided in the timing lever Is a governor advance device having a shape in which the weight flying position is unlikely to change due to the inertial force generated in the timing lever due to the angular acceleration of the drive shaft. 2. The position of the center of gravity of the weight is such that the tangent line extending from the center of gravity on an arc passing through the center of gravity about the drive shaft toward the spindle of the weight is the spindle of the weight and the center of rotation of the drive shaft. The governor advancement device according to claim 1, wherein the position is such that it intersects with a line segment that connects 3. A cam groove provided on the timing lever,
The angle between the common normal line at the contact point with the drive pin and the movement direction of the weight is large, and the angle between the common normal line at the contact point with the drive pin and the movement direction of the timing lever is small. The governor advancement device according to claim 1. 4. A cam groove provided on the timing lever,
The largest friction coefficient between the drive pin and
When it is set to max, the range of magnitude of the angle θt formed by the common normal line at the contact point between the drive pin and the cam groove and the moving direction of the timing lever is θt <90 ° -tan ^−1.
A range of magnitude of an angle θw formed by a common normal line at a contact point between the drive pin and the cam groove and a moving direction of the weight is θw> 90 ° -tan ^-1 μmax. The governor advancement device according to item 3. 5. A cam groove provided on the timing lever,
5. The shape according to claim 3, wherein the angle formed by the common normal line at the contact point between the drive pin and the cam groove and the movement direction of the weight increases at a small advance angle of the rotor shaft. Governor advance device.