JPH10196327A - Electromagnetically-driven valve system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetically-driven valve system for an internal combustion engine to improve responsiveness during high speed operation and hardly cause the occurrence of surging. SOLUTION: A disc-form plunger 5 is fixed on the valve stem 2 of a valve element 1, and electromagnets 6 and 7 to attract the two surfaces of the plunger are arranged on the two surfaces of a plunger 5 in a state to be positioned facing each other. First and second springs 8 and 9 are brought into contact with the two surfaces of the plunger 5 and the plunger 5 is energized toward the intermediate position between two attraction positions. One first spring 8 is arranged on the inner peripheral side of the electromagnet 6 and the other second spring 9 is arranged on the outer peripheral side of the electromagnet 7. By bringing the central part and the outer peripheral part of the plunger 5 into contact with the springs 8 and 9, inclination is prevented from occurring and responsiveness during high speed operation is ensured. By differing the coil diameters of the springs 8 and 9 from each other, surging is prevented from occurring as a spring constant is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven valve train for an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional electromagnetically driven valve train for an internal combustion engine, for example, one having a configuration disclosed in Japanese Patent Application Laid-Open No. 7-324609 is known. In this type of electromagnetically driven valve gear, as shown in FIG. 3, an intake / exhaust valve 24 for opening / closing an opening 23 to a combustion chamber of an intake / exhaust port 22 is provided in a cylinder head 21 of an internal combustion engine. A disc-shaped plunger 26 is fixed to an upper end of a valve shaft 25 extending upward from the valve body, and a first spring 27 and a second spring 28 are respectively applied to both surfaces of a central portion of the plunger 26. The plunger 26 is configured to be elastically positioned at a predetermined position. And plunger 2
Electromagnets 29 and 30 for adsorbing the magnets 6 are arranged so as to face each other on both surfaces of the outer periphery of the magnet 6. In particular,
Springs 27 and 28 are arranged in bottomed holes 31 and 32 formed in the centers of the yokes 29a and 30a of the electromagnets 29 and 30, and an electromagnetic coil 29b is formed in an annular space formed in the outer periphery of the yokes 29a and 30a. , 30b are arranged.

[0003]

However, in the configuration shown in FIG. 3, the plunger 26 is provided only at the central portion thereof and the spring 2
Because of the support of the internal combustion engine 7 and 28, there is a problem that inclination is likely to occur, and the responsiveness during high-speed operation of the internal combustion engine may be deteriorated. The springs 27 and 28 are connected to the electromagnet 2
Since the spring constant is reduced in order to reduce the power consumption of 9 and 30, there is a problem that surging is likely to occur.
In addition, since the coil diameter D of the spring is small, the coil diameter is D, and the wire diameter is d, D / d is small, so that the stress generated at the time of operating the spring is high, and the durability is low.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide an electromagnetically driven valve train for an internal combustion engine which has good responsiveness during high-speed operation, does not easily generate surging, and has excellent durability. Aim.

[0005]

According to the present invention, a disk-shaped plunger is fixed to a valve shaft of a valve body constituting an intake / exhaust valve of an internal combustion engine, and the plunger is sucked so as to face both surfaces of the plunger. An electromagnet is arranged, and a first spring and a second spring are respectively brought into contact with both surfaces of the plunger to urge the plunger toward an intermediate position between the two attracting positions. One is located on the inner circumference of the electromagnet and the other is located on the outer circumference of the electromagnet, and its inclination is prevented by contacting one spring with the center of the disc-shaped plunger and the other with the outer circumference By changing the coil diameter of the spring to make the natural frequency different, the generation of surging is suppressed even if the spring constant is reduced, and the coil diameter is set to D and the wire diameter is changed. Is set to d and D / d is increased. It is obtained so as to improve the durability and reduce the stress generated during operation.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a valve body constituting an intake / exhaust valve of an internal combustion engine, and its valve shaft 2 is extended upward to drive and move the valve body 1 to a valve opening position or a valve closing position. Drive unit 3
Is inserted inside. The tip of the valve shaft 2 is located at a substantially central position in the axial direction of the cylindrical casing 4 of the electromagnetic drive unit 3,
A disc-shaped plunger 5 is fixed to the tip.

A first electromagnet 6 is disposed below the plunger 5 in the casing 4 so as to be fitted on the peripheral wall of the casing 4. A first spring 8 having a coil diameter of D1 and a wire diameter of d1 is disposed in a space between the inner periphery of the first electromagnet 6 and the valve shaft 2, and an upper end thereof is in contact with the plunger 5, The lower end is in contact with the lower end wall of the casing 4. A second electromagnet 7 is disposed above the plunger 5 in the casing 4 at a distance from the peripheral wall of the casing 4 while being fixed to the upper end wall of the casing 4. A second spring 9 having a coil diameter of D2 and a wire diameter of d2 is disposed in a space between the outer periphery of the second electromagnet 7 and the peripheral wall of the casing 4, the lower end of which is in contact with the plunger 5, The upper end is in contact with the upper end wall of the casing 4. The coil diameters D1 and D2 of the first spring 8 and the second spring 9 naturally satisfy D1 <D2.

At the lower part of the inner periphery of the first electromagnet 6, a helical spiral in the same direction as the winding direction of the spring is provided along substantially one third in the longitudinal direction of the first spring 8. An uneven portion 10 is formed, and an upper portion of the outer periphery of the second electromagnet 7 is formed in the same direction as the winding direction of the spring so as to extend along substantially one third of the length direction of the second spring 9. A helical uneven portion 11 is formed, and these uneven portions 10 and 11 are configured to have an auxiliary winding effect on the springs 8 and 9.

According to the above configuration, the plunger 5 is moved to the first position.
And the second springs 8 and 9 urge the valve body 1 toward an intermediate position between the two suction positions, causing a delay in following the valve body 1 during high-speed rotation, or causing the valve body 1 to rebound in the closed position and rebound. Can be prevented from restarting. In addition, the first spring 8 abuts on the central portion of the disc-shaped plunger 5 and the second spring 9 abuts on the outer peripheral portion of the plunger 5, whereby the inclination of the plunger 5 can be reliably prevented. This makes it possible to ensure responsiveness during high-speed operation.

Also, the coil diameter D1 of the first spring 8 and the second
Since the coil diameter D2 of the springs 9 is different, even if the spring constant is reduced in order to reduce the power consumption of the electromagnets 6, 7, the natural frequencies of the springs 8, 9 are different from each other, so that the damper effect increases. And the occurrence of surging can be suppressed. Further, the coil diameter of the second spring 9 is D
2. Since the wire diameter is d2 and D2 / d2 can be increased even with the same spring constant, the stress generated at the time of operating the spring is reduced and the durability is improved.

Further, the first and second springs 8 and 9 have an uneven portion 1
Since 0 and 11 exhibit the side-wound effect, the spring constant increases from the middle during the operation of the first and second springs 8 and 9. Therefore, it is easy to set at the time of assembling and the spring constant becomes large in a practical range, a damping effect is obtained against the waving of the first and second springs 8 and 9, and the surging generation range is shifted to a high frequency side. Can be prevented from occurring.

In the above embodiment, the coil diameter D1 of the first spring 8 at the lower part of the plunger 5 is small, and the coil diameter D2 of the second spring 9 at the upper part is large. Conversely, as shown in FIG. 2, the coil diameter D1 of the lower first spring 8 of the plunger 5 may be increased, and the coil diameter D2 of the upper second spring 9 may be reduced. It is needless to say that the same effect is exerted in the case.

[0014]

According to the electromagnetically driven valve train of an internal combustion engine of the present invention, a disk-shaped plunger is fixed to the valve shaft of the valve body constituting the intake / exhaust valve as described above, and the plunger is mounted on both sides of the plunger. Arrange electromagnets that attract each other so as to face each other,
A first spring and a second spring are respectively brought into contact with both surfaces of the plunger to urge the plunger toward an intermediate position between the attraction positions, and one of the first spring and the second spring is an electromagnet. The inner side of the plunger is located on the outer side of the electromagnet, and the spring is in contact with the central part and the outer part of the disc-shaped plunger from above and below to prevent the inclination of the plunger. And the natural frequencies of the upper and lower springs are different, so that the occurrence of surging can be suppressed even if the spring constant is reduced, and the coil diameter is D and the wire diameter is d.
Since d increases, the stress generated when the spring is actuated is reduced, and effects such as an improvement in durability can be exhibited.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of one embodiment of an electromagnetically driven valve train for an internal combustion engine of the present invention.

FIG. 2 is a longitudinal sectional view showing a schematic configuration of another embodiment of the electromagnetically driven valve train of the internal combustion engine of the present invention.

FIG. 3 is a longitudinal sectional view showing a schematic configuration of a conventional electromagnetically driven valve train for an internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve body 2 Valve shaft 5 Disc-shaped plunger 6 1st electromagnet 7 2nd electromagnet 8 1st spring 9 2nd spring

Claims (1)

[Claims] 1. A disk-shaped plunger is fixed to a valve shaft of a valve body constituting an intake / exhaust valve of an internal combustion engine, and electromagnets for adsorbing the plunger are arranged on both sides of the plunger so as to face each other. The first spring and the second spring are respectively brought into contact with each other to urge the plunger toward an intermediate position between the two attracting positions, and one of the first spring and the second spring is connected to the inner periphery of the electromagnet. An electromagnetically driven valve train for an internal combustion engine, wherein the electromagnetically driven valve train is disposed on the outer side of the electromagnet.