JPH08135417A - Electromagnetic driving type valve device of internal combustion engine - Google Patents

Abstract

PURPOSE: To give proper rotation to a valve element without providing a special mechanism on an electromagnetic driving type valve of an internal combustion engine to drive an intake valve or an exhaust valve of the internal combustion engine. CONSTITUTION: A plunger holder 18 fixed on a valve element 12 of an internal combustion engine is supported by first and second coil springs 32, 34 arranged above and below it. First and second electromagnetic coils 22, 26 to generate electromagnetic force to attract the plunger 20 are provided. Winding directions of the first and second coil springs 32, 34 are made opposite to each other. A high friction coefficient is secured between the first coil spring 32 and a spring guide 36, and a low friction coefficient is secured between the second coil spring 34 and a spring guide 37.

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 device for an internal combustion engine, and more particularly to an electromagnetically driven valve device for an internal combustion engine that drives an intake valve or an exhaust valve of the internal combustion engine by electromagnetic force.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-3-44010.
As disclosed in the publication, there is known an electromagnetically driven valve device for an internal combustion engine, which drives an intake valve or an exhaust valve of the internal combustion engine by an electromagnetic force generated by an electromagnetic coil. According to such an electromagnetically driven valve device, a cam mechanism or the like for valve driving, which is generally required in an internal combustion engine, is not required, and the valve opening / closing timing can be arbitrarily changed, so that the operating state of the internal combustion engine can be changed. It is possible to realize an ideal opening / closing valve timing according to

By the way, in a mechanism for driving an intake valve or an exhaust valve using a cam mechanism, from the viewpoint of suppressing uneven wear of the valve body, an eccentric position on the valve lifter is used as a contact portion with the cam. Are known. According to such a configuration, the rotational torque around the shaft is applied to the valve lifter as the cam rotates, and as a result, the valve body appropriately rotates and uneven wear is prevented.

[0004]

On the other hand, in the above-mentioned conventional electromagnetically driven valve device, the components corresponding to the cam and the valve lifter in the device using the cam mechanism, that is, the valves slide with each other when the valve is driven. This is a configuration having no components. Therefore, in the above-mentioned conventional device, in order to prevent uneven wear of the valve body, it is necessary to separately provide a mechanism for applying an appropriate rotational torque to the valve body.

On the other hand, if such a mechanism is provided separately, there are disadvantages such as an increase in weight of the device, an increase in size of the body, and an increase in cost. In this sense, the conventional electromagnetically driven valve device has a problem that it is not always easy to add a function of preventing uneven wear of the valve body. The present invention has been made in view of the above points,
An object of the present invention is to provide an electromagnetically driven valve device for an internal combustion engine, which can solve the above problems by imparting appropriate rotation to the valve body without providing a special rotating mechanism for the valve body.

[0006]

The above object is to support a plunger fixed to a valve body of an internal combustion engine by means of first and second coil springs arranged on both sides of the plunger, respectively. In an electromagnetically driven valve device for an internal combustion engine that drives the valve body by applying an electromagnetic force to the first coil spring, the winding directions of the first and second coil springs are opposite to each other, and the first coil spring is Coefficient at the contact portion between one end of the second coil spring and the plunger, friction coefficient at the contact portion between one end of the second coil spring and the plunger, and friction coefficient at the other end of the first coil spring and the second Achieved by an electromagnetically actuated valve device of an internal combustion engine having a difference in at least one of friction coefficients at the other end of the coil spring That.

[0007]

In the present invention, the plunger is fixed to the valve body and is supported by the first and second coil springs. Therefore, when an electromagnetic force is applied to the plunger, the first and second coil springs expand and contract, and the valve body opens and closes.

At this time, both ends of the first and second coil springs that support the plunger are relatively rotated in a direction corresponding to the winding direction of the coil spring when the first and second coil springs expand and contract. To do. And the first
Since the winding directions of the first and second coil springs are opposite to each other, when the first and second coil springs expand and contract due to the displacement of the plunger, the first and second coil springs are attached to the plunger. Rotational torques in mutually opposite directions are transmitted from the plungers.

On the other hand, the friction coefficient at both ends of the first coil spring and the friction coefficient at both ends of the second coil spring have a difference in at least one place. Therefore, the rotational torque that acts on the contact portion between the first coil spring and the plunger,
An imbalance occurs between the rotational torque acting on the contact portion between the second coil spring and the plunger.

Therefore, a large rotation torque is applied to the plunger in a biased manner only in one direction, and as a result, appropriate rotation is applied to the valve body as the plunger reciprocates. It will be.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall structure of an electromagnetically driven valve device 10 for an internal combustion engine which is an embodiment of the present invention. In the figure, the valve body 12 is a member that is disposed in the cylinder head with its lower end exposed in the combustion chamber of the internal combustion engine and constitutes an intake valve or an exhaust valve of the internal combustion engine.

That is, the cylinder head of the internal combustion engine is provided with a port having a valve seat for the valve body 12, and the opening / closing of the port is controlled by separating or seating the valve body 12 from the valve seat. An operating shaft 14 is fixed to the valve body 12. Working axis 1
The valve guide 16 and the oil seal 17 are held slidably in the axial direction while ensuring proper sealing performance.

That is, in the electromagnetically driven valve device 10 of this embodiment, in order to ensure the lubricity of each sliding portion,
Lubricating oil is supplied to the inside of the device. The oil seal 17 is provided so that an appropriate amount of lubricating oil flows through the operating shaft 14 into the valve guide 16. Therefore, in the electromagnetically driven valve device 10, an appropriate oil film is formed on the inner circumference of the valve guide 16 to ensure smooth slidability of the operating shaft 14.

A plunger holder 18 is fixed to the upper end of the operating shaft 14. This plunger holder 18
It is a member made of a non-magnetic lightweight alloy such as Ti, Ti-Al, Al, etc., and both surfaces thereof are subjected to treatments such as chrome plating, electroless Ni plating (Kanigen plating), and ceramic Kanigen plating. Plunger holder 18
A plunger 20 is joined to the outer periphery of the. The plunger 20 is a doughnut-shaped member made of a soft magnetic material having Fe, Ni, Co or the like as a base material, and is joined to the plunger holder 18 by a method such as electron beam welding, laser welding, brazing, caulking, or bonding. The same plating treatment as described above is also applied to the surface thereof.

A first electromagnetic coil 22 and a first core 24 are arranged above the plunger 20 with a predetermined distance therebetween. Below the plunger 20, the second electromagnetic coil 26 and the second core 2 are similarly spaced apart by a predetermined distance.
8 are provided. First and second cores 24, 28
Are members made of a magnetic material, and each has a first
Alternatively, it holds the second electromagnetic coils 22 and 26 and is held in a predetermined positional relationship by the outer cylinder 30.

Further, the first and second cores 24, 28 are
A first coil spring 32 and a second coil spring 34, which have a hollow portion near the center thereof and elastically support the plunger holder 18 in the vertical direction, are housed therein. Here, the electromagnetically driven valve device 10 according to the present embodiment.
In consideration of the reason described later, the first coil spring 32
And the second coil spring 34 are arranged so that their winding directions are opposite to each other. The operation and effect of adopting such a configuration will be described in detail later.

By the way, the plunger holder 18 is plated with chrome as described above. Therefore, in the electromagnetically driven valve device 10, the friction coefficient at the contact portion between the first coil spring 32 and the plunger holder 18 and the friction coefficient at the contact portion between the second coil spring 34 and the plunger holder 18 are Both are balanced at relatively low values.

A coil spring for holding the upper end of the first coil spring 32 or the lower end of the second coil spring 34 is provided at the upper end of the first core 24 and the lower end of the second core 28, respectively. Guides 36 and 37 are provided. These coil spring guides 36, 3
7 are processed to have the same surface roughness, and are in contact with the first coil spring 32 or the second coil spring 34 under the same conditions.

By the way, the lubricating oil is supplied to the inside of the electromagnetically driven valve device 10 as described above. This lubricating oil flows from a high place to a low place inside the electromagnetically driven valve device 10, and does not reach between the first coil spring 32 and the coil spring guide 36.
An oil film is formed between the second coil spring 34 and the coil spring guide 37.

Therefore, in this embodiment, a high friction coefficient is secured at the contact portion between the first coil spring 32 and the coil spring guide 36, while the second coil spring 34 and the coil spring are secured. A relatively small coefficient of friction is given to the guide 37. Above the coil spring guide 36, an adjuster 38 for adjusting the amount of deformation of the first and second coil springs 32, 34 is provided. Here, in the present embodiment, the adjuster 38 is adjusted so that the plunger 20 is positioned at the center of the first and second cores 24, 28 in the neutral state in which no electromagnetic force acts. The second coil springs 32 and 34 are balanced.

In the valve drive device 10 having the above structure,
When a current is passed through the first electromagnetic coil 22 to generate a magnetic field that circulates on the inner peripheral side and the outer peripheral side thereof, the first core 2
4, the magnetic flux is circulated in the magnetic circuit composed of the plunger 20 and the air gap therebetween, and the electromagnetic attraction force acting upward in FIG. 1 acts on the plunger 20 in order to realize a more stable state.

On the other hand, when a current is passed through the second electromagnetic coil 26 to generate a magnetic field that circulates on the inner peripheral side and the outer peripheral side thereof, the second core 28, the plunger 20, and the air gap therebetween are formed. A magnetic flux flows through the magnetic circuit, and an electromagnetic attraction force acting downward in FIG. 1 acts on the plunger 20 in order to realize a more stable state. Therefore, the electromagnetic coil 2
If an appropriate electric current is passed through 2 and 26 alternately, it is possible to reciprocate the plunger 20 in the vertical direction, whereby the open / close state of the valve body 12 can be switched.

When the plunger 20 is displaced, the coil springs 32 and 34 are expanded and contracted due to elastic deformation. On the other hand, when the coil spring expands and contracts, it is known that relative rotation occurs at both ends of the coil spring depending on the winding direction of the coil. Therefore, in the configuration in which the first and second coil springs 32 and 34 are arranged above and below the plunger holder 18 as in this embodiment, both ends of the first coil spring 32 are accompanied by the reciprocating motion of the plunger 20. Relative rotation of
The rotational torque caused by the relative rotation of both ends of the second coil spring 34 is applied to the plunger holder 18 and the spring guides 36 and 37.

In this case, as will be described below with reference to FIGS. 2 to 4, according to the configuration of this embodiment, the first and second
The rotational torque generated by the coil springs 32, 34 of
It acts to rotate the plunger holder 18 in only one direction, so that the valve body 12 can be rotated in only one direction. That is, FIG. 2 shows a structure in which the first coil spring 32 and the second coil spring 32 having different winding directions are arranged above and below the plunger holder 18.
And the second coil spring 40 having the same winding direction as the first coil spring 32 is arranged below the plunger holder 18 in FIG. Each is a schematic representation.

The contact portion between the first coil spring 32 and the spring guide 36 can be regarded as substantially fixed because the frictional force acting between them is large. On the other hand, the contact portion between the first coil spring 32 and the plunger holder 18 and the contact portions formed at both ends of the second coil springs 34, 40 are substantially fixed because the friction coefficient of the contact portions is small. It cannot be considered that there is.

Therefore, in FIG. 2 and FIG. 3, an end portion that can be regarded as being substantially fixed is indicated by a "●".
In addition, the situation is displayed by indicating the end portion, which cannot be regarded as being substantially fixed, with “◯”. Further, FIG. 4 is a perspective view of the first coil spring 32, which is shown as a representative example, in order to explain the directions of relative rotation occurring at both ends when the coil spring expands and contracts.

That is, when the coil spring expands and contracts, relative expansion occurs at both ends of the coil spring as described above. More specifically, as shown in FIG. At both ends of the coil spring, the spiral curvature becomes tight when the coil is extended, and the spiral curvature becomes loose when the coil is shortened.
Each rotates relatively.

Therefore, when the first and second coil springs 32 and 40 having the same winding direction are arranged with the plunger holder 18 interposed therebetween as shown in FIG. 3, regardless of the displacement direction of the plunger holder 18, FIG. 3 (A),
(B)), The rotation torque applied to the plunger holder 18 from the first coil spring 32 and the rotation torque applied to the plunger holder 18 from the second coil spring 40 always act as torque in the same direction. .

For this reason, in such a structure, as the first and second coil springs 32, 40 expand and contract, the contact portion between the first coil spring 32 and the spring guide 36, and the second coil spring 34. No rotation torque is applied to the contact portion with the spring guide 37, and the plunger holder 18 only oscillates within the range of a predetermined rotation angle.

On the other hand, as shown in FIG. 2, when the winding directions of the first coil spring 32 and the second coil spring 34 are opposite to each other, the plunger holder 18 moves downward as shown in FIG. 2 (A). When displacing, the first coil spring 32 imparts a clockwise rotation torque in plan view to the plunger holder 18, and the second coil spring 34 imparts a counterclockwise rotation torque in plan view, respectively. It

When the plunger holder 18 is displaced upward as shown in FIG. 2B, a counterclockwise rotation torque from the first coil spring 32 in plan view is generated.
From the second coil spring 34, the clockwise rotation torque in plan view is applied to the plunger holder 18, respectively. By the way, when the rotational torques in different directions are applied to the plunger holder 18 as described above, as a result, the first and second coil springs 32 and 34 and the plunger holder 18 or the spring guides 36 and 37 are separated. Misalignment occurs at the contact area.

Here, as described above, the contact portion between the first coil spring 32 and the spring guide 36 can be regarded as being substantially fixed, so that the expansion and contraction of the first coil spring 32 can be prevented. All of the rotation angles caused by the first coil spring 32 and the plunger holder 18 are caused.
It will be absorbed at the contact part with. Meanwhile, the second
The contact portion between the coil spring 34 and the spring guide 37 can move relatively with a low friction coefficient. Therefore, the rotation angle due to the expansion and contraction of the second coil spring 34 is absorbed by the contact portion between the second coil spring 34 and the plunger holder 18 and the contact portion between the second coil spring 34 and the spring guide 37. It will be enough.

Therefore, when the rotation angle generated in the first coil spring 32 and the rotation angle generated in the second coil spring 34 at the contact portion with the plunger holder 18 are compared, the rotation angles shown in FIGS. ), A large rotation angle is generated in the first coil spring 32. Therefore, the first coil spring 32 and the plunger holder 1
8, the friction force F generated at the contact portion with the first coil 8 and the friction force F generated at the contact portion between the second coil spring 34 and the plunger holder 18 are always equal to each other. According to the torque obtained by subtracting the rotation torque generated by the second coil spring 32 from the rotation torque generated by the spring 32, the second coil spring 32 swings within a predetermined rotation angle range.

On the other hand, the frictional force F acting between the first and second coil springs 32 and 34 and the plunger holder 18 is the first coil spring 32, respectively.
Is a function of the load acting between the plunger holder 18 and the second coil spring 34, or the load acting between the second coil spring 34 and the plunger holder 18. Therefore, the frictional force F thereof fluctuates according to the expansion / contraction state of the first and second coil springs 32 and 34. For example, in the state shown in FIG. 2A, the first coil spring 32 and the plunger holder are The frictional force F generated between the second coil spring 32 and the plunger holder 1 is relatively small.
The frictional force F generated between 8 and 8 becomes relatively large.

Therefore, in the situation shown in FIG. 2A, the first coil spring 32 is superior to the second coil spring 34 in comparison of the rotation angles, but the first and second coil springs 34 are superior to each other.
In comparing the magnitudes of the rotational torques applied to the plunger holder 18 by the coil springs 32 and 34, no significant difference is generated between the two. As a result,
As shown in (A), in the process in which the plunger holder 18 is displaced downward, regardless of the difference in the rotation angle between the first coil spring 32 and the second coil spring 34,
Almost no rotation angle is generated in the plunger holder 18, and the valve body 12 is opened without a large rotational movement.

On the other hand, as shown in FIG. 2B, a relatively large frictional force F is generated between the first coil spring 32 and the plunger holder 18 during the process in which the plunger holder 18 is displaced upward. On the other hand, a relatively small frictional force F is generated between the second coil spring 34 and the plunger holder 18. In this case, FIG.
Contrary to the situation shown in (A), from the viewpoint of not only the rotation angle but also the frictional force, the plunger holder 18 is
2, the plunger holder 18 rotates counterclockwise in the front view in FIG. 2 due to the influence of the first coil spring 32 more strongly than the coil spring 34 of FIG.

As a result, when the vertical displacement of the plunger holder 18 is repeatedly performed, the plunger holder 18,
Also, the valve body 12 is continuously rotated in a single direction, and the function of rotating the valve body 12 is realized without providing any special mechanism. As described above, according to the electromagnetically actuated valve device 10 according to the present embodiment, the valve body 12 can be rotated in a certain direction without being accompanied by disadvantages such as size increase, weight increase, and cost increase of the device. it can.

If the valve body 12 can be rotated in a certain direction in this manner, uneven wear of the valve body 12 can be appropriately prevented, and the lubricating oil or the like flowing out from the valve guide 16 can be removed from the valve. It is also possible to effectively prevent a phenomenon in which a localized deposit is formed by concentrating on a part of the body 12. In this sense, the electromagnetically actuated valve device 10 of the present embodiment does not have any disadvantages,
This has the effect of dramatically improving the durability of the valve body 12 of the internal combustion engine.

By the way, in the above embodiment, there is a difference between the friction coefficient at the contact portion between the first coil spring 32 and the spring guide 36 and the friction coefficient at the contact portion between the second coil spring 34 and the spring guide 37. However, the combination for providing the difference in friction coefficient is not limited to this. For example, the contact portion between the first coil spring 32 and the plunger holder 18, and the second
The friction coefficient of the contact portion between the coil spring 34 and the plunger holder 18 may be different.

[0040]

As described above, according to the present invention, the winding directions of the first and second coil springs arranged on both sides of the plunger are reversed, and both ends of the first and second coil springs are arranged. By making the friction coefficients different, as the first and second coil springs expand and contract,
Rotational torque can be generated that rotates the plunger in only one direction.

Therefore, according to the electromagnetically driven valve device for an internal combustion engine according to the present invention, appropriate rotation can be imparted to the valve body of the internal combustion engine without providing any special rotation mechanism, and It is possible to appropriately prevent uneven wear of the valve while satisfying requirements such as size reduction, cost reduction, and weight reduction.

[Brief description of drawings]

FIG. 1 is a front sectional view of an electromagnetically driven valve device for an internal combustion engine that is an embodiment of the present invention.

FIG. 2 is a diagram (No. 1) for explaining the operation of the electromagnetically driven valve device according to the present embodiment.

FIG. 3 is a diagram (No. 2) for explaining the operation of the electromagnetically driven valve device according to the present embodiment.

FIG. 4 is a perspective view showing a state of relative rotation that occurs when the first coil spring expands and contracts.

[Explanation of symbols]

 10 Electromagnetic Drive Type Valve Device 12 Valve Body 18 Plunger Holder 20 Plunger 32 First Coil Spring 34, 40 Second Coil Spring 36, 37 Spring Guide

Claims (1)

[Claims] 1. A plunger fixed to a valve body of an internal combustion engine, wherein first and second plungers are respectively arranged on both sides of the plunger.
And an electromagnetically driven valve device for an internal combustion engine, which is supported by a second coil spring, and drives the valve body by appropriately applying an electromagnetic force to the plunger, wherein the winding directions of the first and second coil springs are In the opposite direction, the friction coefficient at the contact portion between the one end of the first coil spring and the plunger, the friction coefficient at the contact portion between the one end of the second coil spring and the plunger, and the first coil An electromagnetically driven valve device for an internal combustion engine, wherein at least one of a friction coefficient at the other end of the spring and a friction coefficient at the other end of the second coil spring is different.