JP3565039B2 - Electromagnetic drive device and electromagnetically driven valve train in internal combustion engine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electromagnetic drive device and an electromagnetic drive valve device in an internal combustion engine, and more particularly to a technique for stabilizing operation.
[0002]
[Prior art]
As an electromagnetic drive device, an electromagnetic drive valve device that drives a valve such as an intake / exhaust valve of an internal combustion engine is conventionally provided with an armature provided on a valve stem and opposed to both side surfaces of the armature, A pair of electromagnets for applying electromagnetic attraction to the armature, that is, a valve-opening electromagnet and a valve-closing electromagnet, and a pair of return springs for urging the armature toward both electromagnets, that is, a valve-opening side return spring and And a valve-closing-side return spring (see Japanese Patent Application Laid-Open No. 7-335437).
[0003]
In such an electromagnetically driven valve train, the valve-opening return spring and the valve-closing side return spring are the same in order to uniformly apply the electromagnetic attraction force of the conventional valve-opening electromagnet and valve-closing electromagnet to the armature. Set to specifications.
[0004]
[Problems to be solved by the invention]
As described above, in the conventional electromagnetic drive device in which the valve-opening-side return spring and the valve-closing-side return spring are set to the same specification, at the time of initial setting, the vibration center (neutral point) of the armature spring vibration is: It is located at a central position between the electromagnets that are substantially opposed to each other, and the electromagnetic attraction force of both electromagnets acts evenly on the armature without any problem.
[0005]
However, the neutral point shifts as the deterioration with time of the spring (set of the spring load) progresses.
In an electromagnetically driven valve train that drives intake and exhaust valves of a normal internal combustion engine, the ratio between the valve closing time and the valve opening time is approximately 2: 1. Since the compression time is longer than the compression time of the valve-closing-side return spring when the valve is opened, the aging of the valve-opening-side return spring is greater than the aging of the valve-closing-side return spring. The neutral point shifts to the valve-closing electromagnet side, and as a result, the electromagnetic attraction force of the valve-opening electromagnet acting on the armature is weakened, and the armature may not be able to be stably attracted and held, and the armature may be closed when the valve is closed. There is a problem that the opening / closing action is not performed stably, for example, the seating speed for the working electromagnet increases.
[0006]
Accordingly, the present invention has been made in view of the above-described conventional problems, and has been provided with an electromagnetic drive device and an electromagnetically driven dynamic motor in an internal combustion engine capable of continuing stable operation by employing a configuration that addresses the progress of aging of the return spring of an armature. It is an object to provide a valve device.
[0007]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 is
An armature, a pair of electromagnets respectively arranged on both side surfaces of the armature to apply electromagnetic attraction to the armature, and a pair of return springs for urging the armature toward both electromagnets. In the electromagnetic drive device
The present invention is characterized in that the set resistance of the other return spring is improved with respect to the one return spring.
[0008]
The invention according to claim 2 is
An armature provided on a valve body, a valve-opening electromagnet and a valve-closing electromagnet which are respectively arranged on both side surfaces of the armature to apply electromagnetic attraction to the armature, and bias the armature toward both electromagnets. And a valve-opening-side return spring and a valve-closing-side return spring.
The maximum stress applied to the valve-opening-side return spring when the valve-opening-side return spring is compressed is set to be smaller than the maximum stress applied to the valve-opening-side return spring when the valve-closing-side return spring is compressed. It is characterized by having done.
[0009]
The invention according to claim 3 is:
The ratio of the maximum stress applied to the valve-closing-side return spring to the maximum stress applied to the valve-opening-side return spring is set to be substantially the ratio between the valve closing time and the valve opening time.
The invention according to claim 4 is
The ratio between the maximum stress applied to the valve-closing-side return spring and the maximum stress applied to the valve-opening-side return spring is set to a ratio of approximately 2 to 1, which is a ratio between the valve closing time and the valve opening time. Features.
[0010]
The invention according to claim 5 is
Instead of setting the maximum stress, the number of open-side return springs is set to be greater than the number of valve-close-side return springs.
The invention according to claim 6 is
Instead of setting the maximum stress, a setting is made such that the setting strength of the open-side return spring is larger than the setting strength of the valve-closing-side return spring.
[0011]
The invention according to claim 7 is
In place of the setting of the maximum stress, the setting rate of the set-side return spring after the valve closing time elapses and the setting rate of the open-side return spring after the valve opening time elapses are set to be substantially the same. Features.
The invention according to claim 8 is
The ratio between the valve closing time and the valve opening time is approximately 2: 1.
[0012]
The operation of the present invention will be described.
In the invention according to the first aspect, in the conventional electromagnetic drive device in which the pair of return springs are set to the same specification, the neutral point increases as the deterioration with time of the spring (set of the spring load) progresses. Shift.
According to the first aspect of the present invention, the set resistance of the other return spring is increased with respect to the one return spring, so that the return spring having the improved set resistance is prevented from deteriorating with time, and the neutral state is improved. It is possible to suppress the point from shifting.
[0013]
In a conventional electromagnetically driven valve train in an internal combustion engine in which the valve-opening-side return spring and the valve-closing-side return spring are set to the same specifications, the deterioration of the spring with time (set of the spring load) proceeds. Accordingly, the neutral point is shifted to the valve closing electromagnet side.
This is because, in the case of an electromagnetically driven valve train that drives the intake and exhaust valves of a normal internal combustion engine, the ratio between the valve closing time and the valve opening time is, for example, approximately 2: 1. This is because the time during which the valve-side return spring is compressed is longer than the time during which the valve-side return spring is compressed when the valve is opened.
[0014]
According to the second aspect of the present invention, the maximum stress applied to the valve-opening-side return spring is set to be smaller than the maximum stress applied to the valve-closing-side return spring. Deterioration is suppressed, and the neutral point can be suppressed from shifting to the valve closing electromagnet side. In particular, as in the inventions according to claims 3 and 4, the ratio between the maximum stress applied to the valve-closing-side return spring and the maximum stress applied to the valve-opening-side return spring is set to be substantially equal to the valve closing time and the valve opening time. By setting the ratio, for example, a ratio of approximately 2: 1 (2: 1), the time during which the valve-opening-side return spring is compressed when the valve is closed is reduced when the valve-opening-side return spring is compressed when the valve is opened. The setting can be made to take into account that the time is longer than it is, which is more effective.
[0015]
According to the fifth and sixth aspects of the present invention, the number of the open-side return springs is set to be larger than the number of the valve-closed return springs. As a result of setting the set strength to a large value, deterioration over time of the valve-opening-side return spring is suppressed, and it is possible to prevent the neutral point from shifting to the valve-closing electromagnet side.
Furthermore, according to the seventh and eighth aspects of the present invention, the setting rate of the set-back return spring after the valve-closing time elapses and the setting rate of the open-side return spring after the valve-opening time elapse are set to be substantially the same. As a result, regardless of the difference between the valve closing time and the valve opening time, the set rates of both return springs are substantially the same. It is possible to prevent the return spring from deteriorating over time and to prevent the neutral point from being shifted to the valve closing electromagnet side.
[0016]
【The invention's effect】
According to the first aspect of the present invention, it is possible to suppress a change in the neutral point of the armature with respect to a change with time of the return spring load, and to obtain a stable operation of the electromagnetic driving device.
According to the second to eighth aspects of the present invention, in the electromagnetically driven valve train that drives the intake and exhaust valves of a normal internal combustion engine, deterioration over time (set of spring load) of the valve-opening-side return spring is suppressed. As a result, the neutral point can be suppressed from shifting to the valve closing electromagnet side.As a result, the electromagnetic attraction force by the valve opening electromagnet acting on the armature can be secured in the same manner as at the time of initial setting, and the armature can be stably held by suction, When the valve is closed, the seating speed of the armature with respect to the valve-closing electromagnet can be prevented from increasing, and the opening and closing operations can be stably performed.
[0017]
In particular, according to the second aspect of the present invention, the above effect can be more effectively achieved by setting the magnitude of the maximum stress applied to the return spring when the return spring is compressed.
Further, according to the third and fourth aspects of the present invention, the setting can be made in consideration of the fact that the time when the valve-closing-side return spring is compressed is longer when the valve is opened, which is more effective.
[0018]
According to the invention according to claim 5, the above operation can be more effectively achieved by setting the number of return springs.
According to the sixth aspect of the present invention, the above-described operation can be more effectively achieved by setting the set strength of the return spring by selecting the spring material of the return spring.
According to the seventh and eighth aspects of the present invention, by selecting the spring material of the return spring, the set ratio of the valve-side return spring after the valve closing time has elapsed and the set of the open-side return spring after the valve open time has elapsed. By setting the ratio to be substantially the same, the above-described operation can be more effectively achieved.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of an electromagnetic drive device and an electromagnetic drive valve device in an internal combustion engine according to the present invention.
That is, in this figure, a cylinder head 1 is provided with an intake port (exhaust port) that opens to a combustion chamber (not shown), and an electromagnetically driven valve train 2 that opens and closes the intake port (exhaust port). ing.
[0020]
Such an electromagnetically driven valve gear 2 includes a housing 3 made of a non-magnetic material provided on the cylinder head 1 and a rectangle which is provided integrally with, for example, the stem 5 of the valve body 4 and is movably housed in the housing 3. Armature 6, a valve-closing electromagnet 7 that generates an electromagnetic force for attracting the armature 6 and closing the valve body 4, and an electromagnetic force for attracting the armature 6 and opening the valve body 4. The generated valve-opening electromagnet 8, a valve-closing-side return spring 9 for urging the armature 6 in the valve closing direction of the valve body 4, and an opening for biasing the armature 6 in the valve opening direction of the valve body 4. And a valve-side return spring 10.
[0021]
The valve-closing electromagnet 7 is fixedly arranged in the housing 3 at a position facing the upper surface of the armature 6 in the housing 3 and has a substantially U-shaped cross-sectional shape opened to the armature 6 side. The coil 12 is housed in a fixed core 11 coaxially surrounding the stem 5.
The valve-opening electromagnet 8 is fixedly arranged in the housing 3 at a position facing the lower surface of the armature 6 in the housing 3 and has a substantially U-shaped cross-sectional shape opened to the armature 6 side. In addition, a coil 14 is housed in a fixed core 13 coaxially surrounding the stem 5.
[0022]
In addition, the fixed cores 11 and 13 are configured so as to correspond to the rectangular armature 6 and have a substantially rectangular cross-sectional shape having rounded corners at four corners.
On the other hand, the valve-closing-side return spring 9 is fixed to the bottom surface of the storage groove 15 and the outer periphery of the lower portion of the stem 5 in the storage groove 15 on the upper surface of the cylinder head 1 so as to apply an upward spring force to the armature 6. And the spring seat 16 provided.
[0023]
The valve-opening-side return spring 10 is provided in the housing 17 attached to the upper surface of the housing 3 so as to apply a downward spring force to the armature 6. It is interposed between a spring seat 19 fixed to the upper end of the stem 5.
Therefore, the return springs 9 and 10 hold the armature 6 at an equilibrium neutral position at the center between the electromagnets 7 and 8 when the electromagnets 7 and 8 are in the demagnetized state. Is located at an intermediate position between the valve closing position and the valve opening position.
[0024]
The operation of the electromagnetically driven valve gear 2 will be described with reference to the conceptual diagram of the device in FIG. 2 and the valve lift state diagram in FIG. 3. The armature 6 is generated by an electromagnetic attraction force generated by energizing the valve closing electromagnet 7. Is sucked, and the valve body 4 is operated to close the valve (a fully closed state in FIG. 2A, see FIG. 3A). At this time, the valve-closing-side return spring 9 is applying a spring force upward to the armature 6, while the valve-opening-side return spring 10 is in a compressed state.
[0025]
Next, the armature 6 is attracted by the electromagnetic attraction generated by energizing the valve-opening electromagnet 8, and the valve element 4 is opened (FIG. 2C, fully open state, FIG. 3B). See ▼). At this time, the valve-opening-side return spring 10 applies a downward spring force to the armature 6, while the valve-closing-side return spring 9 is in a compressed state.
[0026]
When shifting from the fully-closed state to the fully-opened state, the intermediate lift state shown in FIG. 2B, that is, as described above, the valve body 4 is located at the intermediate position between the valve-closed position and the valve-opened position. (See FIG. 3 (3)).
FIG. 4 is a longitudinal sectional view of an electromagnetically driven valve train of another embodiment.
That is, the valve gear 2 of this embodiment is provided with two valve-opening-side return springs, and the other valve-opening-side return spring 10B is arranged inside one valve-opening-side return spring 10A. The two return-opening springs 10B and 10A are arranged in a double inner and outer state, and the inner-outer and double-open return springs 10B and 10A act on the armature 6 with a downward spring force. To accommodate this, in the storage part 17 attached to the upper surface of the housing 3, it is interposed between the spring seat 20 on the upper surface of the storage part 17 and the spring seat 21 fixed to the upper end of the stem 5.
[0027]
Here, in the present invention, in the above-described electromagnetically driven valve train 2, the following settings (1) to (7) are set, and the valve-opening-side return spring 10 is set with respect to the valve-closing-side return spring 9. Improve the sag resistance.
(1) The maximum stress applied to the valve-opening return spring 10 when the valve-opening-side return spring 10 is compressed, compared to the maximum stress σ _A applied to the valve-closing-side return spring 9 when the valve-closing-side return spring 9 is compressed. The stress σ _B is set to be small (σ _A > σ _B ).
(2) In (1), the ratio (σ _A : σ _B ) between the maximum stress σ _A applied to the valve-closing side return spring 9 and the maximum stress σ _B applied to the valve-opening side return spring 10 is substantially closed. Set the ratio between the valve time and the valve open time.
(3) In (2), σ _A : σ _{B is set} to, for example, a ratio (2: 1) of approximately 2 to 1, which is a ratio between the valve closing time and the valve opening time.
(4) The number (for example, two) of the open-side return springs 10A and 10B is set to be larger than the number (for example, one) of the valve-closing-side return spring 9 (see the embodiment of FIG. 4).
(5) By setting the spring materials of the two return springs 9, 10, the setting of the setting strength of the open-side return spring 10 to be larger than the setting strength of the valve-closing-side return spring 9 is set.
(6) by the choice of spring material both return springs 9 and 10, the return opening side of the sag rate and opening time of the spring 9 returns the valve closing side during closing time t ₂ elapsed t ₁ after the elapse spring 10 to the The setting was made to be substantially the same as the set rate (see FIG. 5).
(7) In (6), sets the ratio of closing time _{t 2} and the valve opening time _{t 1} to a ratio of approximately 2: 1.
[0028]
According to such a configuration, the following operation and effect can be obtained.
That is, in a conventional electromagnetically driven valve device in which the valve-opening-side return spring and the valve-closing-side return spring are set to the same specifications, as the spring deteriorates with time (spring load sag), , The neutral point is shifted to the valve closing electromagnet side.
This is because, in an electromagnetically driven valve train that drives intake and exhaust valves of a normal internal combustion engine, the ratio between the valve closing time and the valve opening time is approximately 2: 1. This is because the time during which the return spring is compressed is longer than the time during which the valve-closing-side return spring is compressed when the valve is opened.
[0029]
According to the above setting (1), the maximum stress σ _B applied to the valve-opening-side return spring 10 is smaller than the maximum stress σ _A applied to the valve-closing-side return spring 9 (σ _A > σ _B). As a result, the deterioration with time of the valve-opening-side return spring 10 (set of the spring load) is suppressed, and the neutral point can be prevented from shifting to the valve-closing electromagnet 7 side.
In particular, as in the settings of (2) and (3), by setting σ _A : σ _B to a ratio between the substantially valve closing time and the valve opening time, for example, a ratio of approximately 2: 1 (2: 1). The setting can be made in consideration of that the time during which the valve-opening-side return spring 10 is compressed when the valve is closed is longer than the time during which the valve-closing-side return spring 9 is compressed when the valve is opened. It is valid.
[0030]
Further, according to the above settings (4) and (5), the number (for example, two) of the open-side return springs 10A and 10B is set to be larger than the number (for example, one) of the valve-closing-side return spring 9. As a result, the strength of the opening-side return spring 10 is set to be larger than the strength of the valve-closing-side return spring 9, so that the valve-opening-side return springs 10, 10A, and 10B deteriorate with time (spring load reduction). And the neutral point can be prevented from shifting to the valve-closing electromagnet 7 side.
[0031]
Further, according to the settings of (6) and (7), the set rate of the valve-side return spring 9 when the valve closing time has elapsed and the set rate of the open-side return spring 10 when the valve open time has elapsed are determined. As a result of setting to be substantially the same, the set rates of the two return springs 9 and 10 become substantially the same regardless of the difference between the valve closing time and the valve opening time. (Set of load) is suppressed from progressing over time with respect to the valve-closing-side return spring 9, and the neutral point can be suppressed from shifting to the valve-closing electromagnet 7 side.
[0032]
Accordingly, as described above, deterioration with time (set of spring load) of the valve-opening side return spring 10 can be suppressed, and the neutral point can be prevented from shifting to the valve-closing electromagnet 7 side. The electromagnetic attraction force to the armature 6 can be secured in the same manner as at the time of the initial setting, the armature 6 can be stably attracted and held, and the seating speed of the armature 6 with respect to the valve-closing electromagnet 7 when the valve is closed can be suppressed from increasing. The valve opening / closing action can be performed stably.
[0033]
In the above embodiment, the invention has been described in which the set resistance of the valve-opening-side return spring is improved with respect to the valve-closing-side return spring of the electromagnetically driven valve train. The invention according to the present invention is not limited to an electromagnetic drive device for driving a valve, i.e., an armature, a pair of electromagnets disposed opposite to each other on both side surfaces of the armature to apply an electromagnetic attraction to the armature, and the armature. And a pair of return springs biasing both electromagnets, respectively, wherein the set resistance of the other return spring is improved with respect to the one return spring. Therefore, it is possible to suppress a change in the neutral point of the armature with respect to a change in the return spring load with time, and to obtain a stable operation of the electromagnetic drive device.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of an electromagnetic drive device and an electromagnetic drive valve device in an internal combustion engine according to the present invention. FIG. Valve state, (B) fully open state, (C) intermediate lift state [Fig. 3] Valve lift state diagram [Fig. 4] Longitudinal sectional view of another embodiment [Fig. 5] Valve open side return spring and valve closing Characteristic diagram showing set rate with time of side return spring [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Electromagnetic drive type valve train 3 Housing 4 Valve body 5 Stem 6 Armature 7 Valve closing electromagnet 8 Valve opening electromagnet 9 Valve closing side return spring 10 Valve opening side return spring 10B, 10A Valve opening side return spring

Claims (8)

An armature, a pair of electromagnets respectively arranged on both side surfaces of the armature to apply electromagnetic attraction to the armature, and a pair of return springs for urging the armature toward both electromagnets. In the electromagnetic drive device
An electromagnetic drive device wherein the set resistance of one return spring is improved with respect to the other return spring. An armature provided on a valve body, a valve-opening electromagnet and a valve-closing electromagnet which are respectively arranged on both side surfaces of the armature to apply electromagnetic attraction to the armature, and bias the armature toward both electromagnets. And a valve-opening-side return spring and a valve-closing-side return spring.
The maximum stress applied to the valve-opening-side return spring when the valve-opening-side return spring is compressed is set to be smaller than the maximum stress applied to the valve-opening-side return spring when the valve-closing-side return spring is compressed. An electromagnetically driven valve train in an internal combustion engine. The ratio of the maximum stress applied to the valve-closing-side return spring to the maximum stress applied to the valve-opening-side return spring is set to a substantially ratio between the valve closing time and the valve opening time. An electromagnetically driven valve train in an internal combustion engine. The ratio of the maximum stress applied to the valve-closing-side return spring to the maximum stress applied to the valve-opening-side return spring is set to a ratio of approximately 2 to 1, which is a ratio between the valve closing time and the valve opening time. An electromagnetically driven valve train in an internal combustion engine according to claim 3. 3. An electromagnetically driven valve train in an internal combustion engine according to claim 2, wherein, instead of setting the maximum stress, the number of open side return springs is set to be larger than the number of valve close side return springs. . 3. The electromagnetic drive in an internal combustion engine according to claim 2, wherein, instead of setting the maximum stress, the set strength of the open-side return spring is set to be larger than the set strength of the valve-closed return spring. Type valve train. Instead of the setting of the maximum stress, the setting rate of the set-side return spring after the valve closing time elapses and the setting rate of the open-side return spring after the valve opening time elapses are set to be substantially the same. An electromagnetically driven valve train in an internal combustion engine according to claim 2, wherein 8. An electromagnetically driven valve train in an internal combustion engine according to claim 7, wherein the ratio between the valve closing time and the valve opening time is approximately 2: 1.

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