JP2003065456A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an effect of lubricant adhered to a surface of an armature on an accuracy of opening and closing valve timings of a valve element in regard to a solenoid valve suitable as a mechanism driving an intake valve or an exhaust valve of an internal combustion engine by electromagnetic force. SOLUTION: The armature 3 transmitting electromagnetic force to the valve body 12 is provided. An upper side electromagnet 48 and a lower side electromagnet 42 are arranged above and below the armature 30. Wet type bushes 50 and 52 are provided slidably holding an armature shaft 28 fixed to the armature 30. A surface of the armature 30 is covered by an oil repellent coat.

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, and more particularly to an electromagnetically driven valve suitable as a mechanism for driving an intake valve or an exhaust valve of an internal combustion engine with an electromagnetic force.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 11-36829 discloses an electromagnetically driven valve that drives an intake valve or an exhaust valve of an internal combustion engine with an electromagnetic force. The electromagnetically driven valve includes an armature made of a magnetic material and two electromagnets arranged above and below the armature. An armature shaft that penetrates the center of the electromagnet is fixed to the center of the armature.

The armature shaft is axially slidably held by a bush provided in an electromagnet.
Further, a valve shaft communicating with the valve body is connected to the lower end of the armature shaft. Lubricating oil is externally supplied to the bush in order to reduce the sliding resistance of the armature shaft.

According to the electromagnetically driven valve having the above structure, by supplying the exciting current to the upper electromagnet, the armature can be drawn toward the electromagnet and the valve body can be fully closed. Further, when the exciting current to the upper electromagnet is stopped and the exciting current is supplied to the lower electromagnet, the armature can be drawn to the lower electromagnet and the valve body can be fully opened. Therefore, according to the conventional electromagnetically driven valve, the valve body can be arbitrarily opened and closed by appropriately supplying the exciting current to the two electromagnets.

[0005]

In the conventional electromagnetically driven valve described above, the lubricating oil supplied to the bush reaches the surface of the armature along the armature shaft. When the armature is attracted to the electromagnet, the lubricating oil that has reached the surface of the armature serves as an oil film interposed between the two and enhances their adhesion. As a result, if the above oil film is present,
As compared with the case where the oil film does not exist, the armature becomes difficult to separate from the electromagnet after the excitation current is stopped.

In the electromagnetically driven valve, in order to open and close the valve body with desired timing with high accuracy, it is desirable that the delay until the armature separates from the electromagnet after the supply of the exciting current to the electromagnet is stopped. In this respect, in the conventional electromagnetically driven valve described above, the lubricating oil that has reached the surface of the armature has been one of the factors that deteriorate the opening / closing timing accuracy of the valve element.

The present invention has been made in order to solve the above problems, and it is possible to sufficiently suppress the influence of the lubricating oil reaching the surface of the armature on the accuracy of the opening / closing timing of the valve body. The purpose is to provide a drive valve.

[0008]

The invention according to claim 1 is
An electromagnetically driven valve that opens and closes a valve body by an electromagnetic force, wherein an electromagnet that generates the electromagnetic force, an armature that is arranged to face the electromagnet, an armature shaft fixed to the armature, the armature, and the armature. A wet holding part that slidably holds the armature shaft by using lubricating oil and a contact surface between the armature and the electromagnet so that a state where the electromagnets are in contact with each other and a state where they are separated from each other can be realized. And an oil-repellent coating formed on.

A second aspect of the present invention is the electromagnetically driven valve according to the first aspect, wherein the armature includes a magnetic portion made of a magnetic material containing silicon, and the oil-repellent coating is a fluorocarbon layer. And a silane coupling layer for coupling the fluorocarbon layer and the magnetic part.

According to a third aspect of the present invention, in the electromagnetically driven valve according to the first aspect, the armature includes a magnetic portion made of a magnetic material containing silicon, and the oil-repellent coating is methylhydrogen. A siloxane layer is included.

A fourth aspect of the present invention is the electromagnetically driven valve according to any one of the first to third aspects, wherein a holding block that holds the electromagnet is interposed between the electromagnet and the holding block. And a cushioning material to be used.

The invention according to claim 5 is the electromagnetically driven valve according to any one of claims 1 to 4, wherein the valve shaft fixed to the valve body and the valve shaft are slidably held. And a valve guide, wherein the valve shaft has a carbon relief between the sliding portion that slides on the inner wall of the valve guide and the valve body, the carbon relief making the valve shaft thinner than the sliding portion. The carbon relief is formed so as to be located outside the valve guide when the electromagnetically driven valve is stopped.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that elements common to each drawing are denoted by the same reference numerals, and redundant description will be omitted.

Embodiment 1. FIG. 1 is a cross-sectional view for explaining the configuration of an electromagnetically driven valve 10 that is Embodiment 1 of the present invention. The electromagnetically driven valve 10 shown in FIG. 1 includes a valve body 12 that functions as an exhaust valve of an internal combustion engine. Disc 12
Is arranged in the exhaust port 14 of the internal combustion engine. The exhaust port 14 is provided with a valve seat 16, and the exhaust port 14 is opened and closed by seating the valve body 12 on the valve seat 16 or separating from the valve seat 16.

The valve body 12 is fixed to the tip of the valve shaft 18. The valve shaft 18 is slidably held by a valve guide 20. Above the valve guide 20,
A lower retainer 22 is fixed to the valve shaft 18. Below the lower retainer 22, a lower spring 24 that generates an elastic force that urges the valve shaft 18 upward is disposed.

The upper end of the valve shaft 18 is also connected to an armature shaft 28 via a lash adjuster 26.
The lash adjuster 26 includes the valve shaft 18 and the armature shaft 2.
It is a functional component having a function of appropriately expanding and contracting as necessary to appropriately change the relative position of 8. According to the lash adjuster 26, regardless of the thermal expansion of the valve shaft 18, the play between the armature shaft 28 and the valve shaft 18 can be made zero, and the valve body 12 can always be kept in a state in which it can be displaced to the fully closed position. it can.

The armature shaft 28 is provided so as to extend along the central axis of the armature 30. The armature 30 is a disk-shaped member made of a magnetic material.
The armature 30 is required to have a characteristic of generating a high magnetic flux density in a low magnetic field region of a static magnetic field and suppressing iron loss (eddy current loss) in an alternating magnetic field to be sufficiently small. In order to meet this requirement, in the present embodiment, the armature 30 is made of a Fe—Si magnetic material.

An upper retainer 32 is fixed to the upper end of the armature shaft 28. An upper spring 34 that generates an elastic force that urges the armature shaft 28 downward is disposed above the upper retainer 32. The upper end position of the upper spring 34 is regulated by the adjuster 36. In the electromagnetically driven valve 10, the armature shaft 2
The neutral position of 8 is adjusted by the adjuster 36.

Below the armature 30, there is a lower core 38.
And a lower electromagnet 42 including a lower coil 40 is arranged. In addition, the upper core 4 is provided above the armature 30.
An upper electromagnet 48 including the upper coil 4 and the upper coil 46 is arranged. The central portion of the lower core 38 and the upper core 4
Wet type bushes 50 and 52 for slidably holding the armature shaft 28 are arranged in the central portion of FIG. Lubricating oil is supplied to each of the bushes 50 and 52 through an oil passage (not shown).

Above the upper core 44, a cap member 54 for holding the adjuster 36 is arranged. The lower core 38, the upper core 44, and the cap member 54 are fixed to the holding block 56, respectively.
A cushioning material 58 is sandwiched between the holding block 56 and the lower core 38 and between the holding block 56 and the upper core 44. According to the cushioning material 58, the armature 3
Vibrations associated with zero motion can be damped sufficiently small before being transmitted to the holding block 52.

The position of the armature shaft 28 is determined by the electromagnetically driven valve 1
When 0 is stopped, that is, when the exciting current is not supplied to any of the lower coil 40 and the upper coil 46, the armature 30 is substantially in the lower core 38 and the upper core 4.
It is adjusted to be located at the center of 4. In addition, each part of the electromagnetically driven valve 10 is adjusted so that the valve body 12 is located at approximately the center between the fully open position and the fully closed position at that time.
Hereinafter, those positions will be referred to as the armature 30 or the valve body 12
"Neutral position".

In FIG. 1, the armature 30 is moved to the upper electromagnet 48 by supplying an exciting current to the upper coil 46.
And the valve body 12 is in a fully closed state. At this time, the valve body 12 is seated on the valve seat 16, that is, in a fully closed state.

When the energization of the upper coil 46 is stopped from the state shown in FIG. 1, the armature 30 is urged by the lower spring 24 and the upper spring 34,
It moves beyond the neutral position to the vicinity of the lower electromagnet 42. When the exciting current is supplied to the lower coil 40 at the timing when the armature 30 approaches the lower electromagnet 42, the armature 30 can be attracted to the lower electromagnet 42 and the valve body 12 can be displaced to the fully open position. After that, the opening / closing operation of the valve body 12 can be continued by alternately interrupting and supplying the exciting current on the lower coil 40 side and the upper coil 46 side.

The electromagnetically driven valve 10 is provided with the lower spring 24 and the upper spring 34 as described above. These springs 24 and 34 expand and contract with the opening / closing operation of the valve body 12, and along with the expansion and contraction, transmit a rotational force in a fixed direction to the armature shaft 28. As a result, armature axis 2
8 and the armature 30 continue to rotate in a fixed direction while the opening / closing operation of the valve body 12 is repeated.

During operation of the electromagnetically driven valve 10, the collision of the armature 30 with the lower core 38 or the upper core 44 is repeated with the opening / closing operation of the valve body 12. At this time, the vibration caused by the collision of the armature 30 is transmitted to the lower core 38 or the upper core 44. When this vibration is transmitted from the lower core 38 and the upper core 44 to the holding block 56, the vibration spreads throughout the internal combustion engine and causes large noise. In the present embodiment, the vibration transmitted to the lower core 38 and the upper core 44 is sufficiently damped by the cushioning material 58. Therefore, a large vibration is not transmitted to the holding block 56, and excellent quietness is realized in the internal combustion engine.

Next, the second feature of the electromagnetically driven valve 10 of this embodiment will be described with reference to FIG. FIG. 2 is an enlarged view showing the periphery of the valve shaft 18 included in the electromagnetically driven valve 10. More specifically, FIG. 2 shows a state where the electromagnetically driven valve 10 is stopped, that is, the armature 30 and the valve body 1.
2 shows the state existing in the neutral position.

As shown in FIG. 2, on the valve shaft 18, a portion slidably held by a valve guide 20 and a valve body 12 are provided.
A carbon relief 60 is provided between the two. The valve shaft 18 has a diameter D substantially equal to the inner diameter of the valve guide 20 in the portion held by the valve guide 20. In the portion of the carbon relief 60, the diameter of the valve shaft 18 is smaller than the above diameter D by a predetermined amount ΔD.
-It is supposed to be ΔD. In the present embodiment, the carbon relief 60 is formed such that its upper end position is located below the lower end position of the valve guide 20 while the electromagnetically driven valve 10 is stopped. Fig. 2 shows carbon relief 6
A state where a distance of a predetermined length h is ensured between the upper end of 0 and the lower end of the valve guide 20 is shown.

Immediately after the internal combustion engine is stopped (immediately after the electromagnetically driven valve 10 is stopped), the oil adhering to the inside of the exhaust port 14 and the like flows downward from above. Further, at that time, the inside of the exhaust port 14 is at a high temperature to the extent that the oil that has flowed down in this way is air-baked. Therefore, carbon is likely to adhere to the portion of the valve shaft 18 below the valve guide 20 while the internal combustion engine is stopped.

When the upper end position of the carbon relief 60 when the electromagnetically driven valve 10 is stopped is higher than the lower end position of the valve guide 20, that is, the carbon relief 6
The upper end of 0 is the valve guide 2 when the electromagnetically driven valve 10 is stopped.
In the case where it enters into 0 and becomes crowded, the inner diameter D of the valve guide 20 and the inner diameter D- of the valve shaft 18 are provided at the lower end of the valve guide 20.
A gap corresponding to the difference “ΔD” from ΔD is generated.

With such a gap formed, the valve shaft 18
As carbon adheres to the
A state of entering the valve guide 20 through the gap is formed. After such a state is formed, when the electromagnetically driven valve 10 is activated, carbon is not caught between the valve guide 20 and the valve shaft 18 when the valve body 12 moves toward the fully closed direction. Occurs, and the sliding resistance increases remarkably temporarily.

In the electromagnetically driven valve 10, when the sliding resistance of the valve shaft 18 increases, the operation of the valve body 12 is stopped or the operation is delayed. For this reason, in order to operate the electromagnetically driven valve 10 smoothly, it is important to reliably prevent carbon from becoming trapped that would increase the sliding resistance of the valve shaft 18.

In the present embodiment, the valve shaft 18 is constructed so that the upper end of the carbon relief 60 is located below the lower end of the valve guide 20 by a predetermined length h when the electromagnetically driven valve 10 where the carbon sludge deposition is stopped. ing. With this configuration, it is possible to reliably prevent the carbon attached to the valve shaft 18 from entering the inside of the valve guide 20. The carbon formed without entering the inside of the valve guide 20 is scraped off by the valve guide 20 as the valve shaft 18 slides. At this time, the valve shaft 18
No large sliding resistance occurs. Therefore, according to the electromagnetically driven valve 10 of the present embodiment, it is possible to always realize good starting characteristics without being affected by the adhesion of carbon to the valve shaft 18.

Next, referring to FIGS. 3 and 4 together with FIG. 1, the third characteristic of the electromagnetically driven valve 10 will be described.
As shown in FIG. 1, the electromagnetically driven valve 10 of the present embodiment includes wet type bushes 50 and 52 that hold the armature shaft 28. The lubricating oil supplied to the bushes 50, 52 reaches the surface of the armature 30 along the armature shaft 28. This lubricating oil is the armature 3 as it is.
When it remains on the surface of 0, the armature 30 moves to the lower electromagnet 4
An oil film is generated between the two or the upper electromagnets 48 when they come into close contact with each other.

Such an oil film, when the armature 30 that is in close contact with the lower electromagnet 42 or the upper electromagnet 48 tries to separate from them, generates a force in a direction that prevents the separation. It is desirable that such a force does not occur in order to smoothly operate the electromagnetically driven valve 10. Therefore, in the present embodiment, in order to avoid the formation of the above oil film as much as possible, the armature 30 is configured as described below.

FIG. 3A is a perspective view of the armature 30 and the armature shaft 28. 3B is a cross-sectional view obtained by cutting the armature 30 along the line BB shown in FIG.

As shown in FIG. 3A, the armature 30
Has a plurality of oil drain grooves 62 formed radially. In the present embodiment, the oil drain groove 62 is provided on the upper surface side of the armature 30 where the lubricating oil easily collects. According to the oil drain groove 62, it is possible to capture the lubricating oil that has reached the surface of the armature 30 and reduce the amount of the lubricating oil that forms the base of the oil film.

As shown in FIG. 3B, the armature 30
Includes a magnetic portion 64 made of a Fe—Si magnetic material, and an oil-repellent coating 66 that covers the surface of the magnetic portion 64. The oil-repellent coating 66, together with the surface of the armature 30,
It is formed so as to also cover the inside of the oil drain groove 62.

FIG. 4 is a diagram showing the structure of the armature 30 at the molecular structure level. Silicon oxide generated by natural oxidation is present on the surface of the magnetic portion 64. The oil-repellent coating 66 includes a silane coupling layer 68 that binds to the silicon oxide, and a fluorocarbon layer 70 formed on the silane coupling layer 68.

The silane coupling layer 68 and the fluorocarbon layer 70 are each formed by a known method and
It can be formed at a film forming temperature of 200 ° C. or less. The silane coupling layer 68 has a property of firmly bonding the inorganic material containing silicon (the magnetic portion 64) and the organic layer such as the fluorocarbon layer 70. Moreover, the fluorocarbon layer 70 has excellent oil repellency. Therefore,
According to the structure shown in FIG. 4, the oil-repellent coating 66 that covers the surface of the magnetic portion 64 with a strong bonding force and that exhibits excellent oil repellency.
Can be realized.

The surface of the armature 30 has an oil-repellent film 66.
When covered with, the lubricating oil that has flowed down onto the armature 30 becomes spherical and moves on its surface. As a result, the lubricating oil is easily captured by the oil drain groove 62 or falls off from the surface of the armature 30. In particular, in the electromagnetically driven valve 10 of the present embodiment, as described above, the armature 30 rotates with the opening / closing operation of the valve body 12. Therefore, the lubricating oil that has flowed down onto the surface of the armature 30 is promptly removed from the surface by the centrifugal force.

When the lubricating oil reaching the surface of the armature 30 is promptly removed from the surface as described above,
Even when the armature 30 is in contact with the upper electromagnet 48, an oil film that prevents the two from separating from each other is not formed between them. Therefore, according to the electromagnetically driven valve 10 of the present embodiment, it is possible to achieve excellent control accuracy regarding the opening / closing timing of the valve body 12 while using the wet type bushes 50, 52.

The silane coupling layer 68 and the fluorocarbon layer 70 used as constituent elements of the oil-repellent coating 66 in this embodiment show good wettability with respect to the material used as the base in this embodiment. It has a characteristic that it can sufficiently coat the base with an extremely thin film thickness. Therefore, according to the structure of the present embodiment,
Oil-repellent film 66 showing stable and high oil repellency over the entire surface
Can be formed with an extremely thin film thickness of about 20 to 50 angstroms.

The oil-repellent film 66 repeatedly collides with the upper electromagnet 48 as the armature 30 moves. Therefore,
The oil-repellent film 66 is required to have high durability. The thicker the oil-repellent film 66, the more easily cracks are generated due to the effect of bending due to the collision with the upper electromagnet 48. In order to prevent the occurrence of cracks, the oil-repellent coating 66 has a thickness of 50.
It is preferably 00 angstroms or less. In this embodiment, the film thickness of the oil-repellent film 66 can be set to 20 to 50 angstroms, which is sufficiently smaller than the desired film thickness. Therefore, according to the structure of the present embodiment,
High durability can be imparted to the oil-repellent coating 66.

In the electromagnetically driven valve 10, the armature 30
The electromagnetic force acting between the upper electromagnet 48 and the upper electromagnet 48 becomes larger as the air gap between them becomes smaller. More precisely,
The electromagnetic force becomes larger as the distance between the magnetic portion 64 of the armature 30 and the upper core 44 becomes shorter. That is, in the configuration of the present embodiment, the oil-repellent coating 66 is an air gap as a constituent element of the magnetic circuit, and the thinner the film thickness, the better in order to efficiently generate a large electromagnetic force.

As described above, in this embodiment, the oil-repellent coating 66 has a sufficiently thin thickness of 20 to 50 angstroms. Therefore, according to the structure of the present embodiment,
Even though the magnetic portion 64 of the armature 30 is covered with the oil-repellent coating 66, the armature 30 is not covered by the upper electromagnet 48.
A large magnetic flux density can be efficiently generated when in contact with.

The magnetic characteristics of the magnetic portion 64 of the armature 30 may be deteriorated by the influence of thermal strain when the armature 30 is heat-treated at a high temperature. In the present embodiment, the temperature of the heat treatment for forming the oil repellent film 66 is 2 as described above.
The temperature is set to 00 ° C. or less, that is, the temperature that does not deteriorate the magnetic characteristics of the magnetic portion 64. Therefore, the structure of the armature 30 shown in FIG. 4 can be realized without deteriorating the magnetic characteristics of the magnetic portion 64.

By the way, in the above-described first embodiment, the oil drain groove 62 and the oil-repellent coating 66 are provided in the armature 3.
However, the present invention is not limited to this. That is, the oil drain groove 62 and the oil repellent film 66 may be formed on both the upper surface and the lower surface of the armature 30.

Further, in the above described first embodiment,
Although the oil drain groove 62 and the oil repellent film 66 are provided on the surface of the armature 30, the present invention is not limited to this. That is, the oil drain groove 62 and the oil repellent film 6
6 may be provided on the electromagnets 42, 48 side instead of the surface of the armature 30 or together with the surface of the armature 30.

Embodiment 2. Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. The electromagnetically driven valve of the present embodiment has the same configuration as the electromagnetically driven valve 10 of the first embodiment, except for the structure of the oil repellent film that covers the surface of the armature. Hereinafter, for convenience, the same reference numerals as those in the first embodiment will be used to describe the configuration of the electromagnetically driven valve of the present embodiment.

FIG. 5 is a diagram showing the structure of the armature 30 used in the electromagnetically driven valve of this embodiment at the molecular structure level. As shown in FIG. 5, in the present embodiment, the oil-repellent coating 66 that covers the magnetic portion 64 of the armature 30 is composed of a layer of methylhydrogensiloxane.

Methyl hydrogen siloxane is strongly bonded to silicon oxide existing on the surface of the magnetic portion 64 by a siloxane bond, and exhibits excellent oil repellency like fluorocarbon. Further, the oil-repellent coating 66 in the present embodiment is similar to that in the first embodiment,
It is possible to form a film at a temperature of 200 ° C. or less, and 50
Sufficiently stable oil repellency can be realized with a film thickness sufficiently thinner than 00 angstrom. Therefore, according to the electromagnetically driven valve of the present embodiment, the same effect as that of the electromagnetically driven valve 10 of the first embodiment can be obtained.

Embodiment 3. Next, a third embodiment of the present invention will be described with reference to FIG. In the first or second embodiment described above, the object to which the present invention is applied is a core having a cylindrical bulk structure (lower core 38 and upper core 44).
It is limited to the electromagnetically driven valve 10 having. However, the electromagnetically driven valve to which the present invention can be applied is not limited to this type. That is, the present invention can be applied to an electromagnetically driven valve having a rectangular laminated structure core.

FIG. 6A is a diagram for explaining the structure of the electromagnetically driven valve 80 according to the third embodiment of the present invention. Further, FIG. 6B shows a cross section of the main part of the electromagnetically driven valve 80.
It is the figure represented by the arrow B shown in FIG. 6 (A).

The electromagnetically driven valve 80 shown in FIGS. 6A and 6B is provided with a lower core 82 and an upper core 84 having a rectangular laminated structure. Each of the lower core 82 and the upper core 84 is formed by laminating a plurality of magnetic plates such as silicon steel plates in a mutually insulated state. The above magnetic plates are laminated in a state in which they are in close contact with each other in the direction perpendicular to the paper surface of FIG. 6A, that is, in the left-right direction of FIG. 6B.

Inside the lower core 82 and the upper core 84, respectively, as in the case of the lower core 38 and the upper core 44 in the first embodiment, respectively,
An unillustrated lower coil or upper coil is built in. According to the core having the rectangular laminated structure, when the magnetic flux density generated by these coils changes, the eddy current loss caused by the change can be suppressed to be small. Therefore, according to the electromagnetically driven valve 80 of the present embodiment, higher energy efficiency can be realized as compared with the electromagnetically driven valve 10 of the first embodiment.

The electromagnetically driven valve 80 of this embodiment has a bottom plate 86 below the lower core 82, and also has a lower core 8
2 is provided with a lower side wall 88. Further, a cap member 90 is provided above the upper core 84, and an upper side wall 92 is provided around the upper core 84. Then, under the bottom plate 86, between the bottom plate 86 and the lower core 82, between the lower side wall 88 and the upper side wall 92, or the upper core 8.
A cushioning member 94 is provided between the cap 4 and the cap member 90.

According to the cushioning material 94, similarly to the cushioning material 58 in the first embodiment, the vibration transmitted to the lower core 82 or the upper core 84 along with the operation of the armature 30 can be sufficiently damped. Therefore, the electromagnetically driven valve 80 of the present embodiment can also achieve the same quietness as the electromagnetically driven valve 10 of the first embodiment.

Further, the electromagnetically driven valve 80 of the present embodiment has the carbon relief 60 which satisfies the same conditions as those of the first embodiment. Therefore, according to the electromagnetically driven valve 80 of the present embodiment, as in the case of the first embodiment, it is possible to prevent carbon from being caught in the valve guide 20 and realize excellent startability.

Further, the electromagnetically driven valve 80 of the present embodiment is provided with the armature 30 having the oil drain groove 62 and the oil repellent coating 66, as in the case of the first or second embodiment. Unlike the case of the first or second embodiment, this armature 30 has the sides shown in FIG. 6 (A) as long sides, and FIG.
Is a rectangle with the short side shown in, and
It is configured to not rotate.

Therefore, in this embodiment, the armature 3
The centrifugal force does not act on the lubricating oil reaching the surface of 0. However, the lubricating oil becomes spherical on the oil-repellent coating 66,
As the armature 30 moves up and down, most of it drops off from the surface of the armature 30. Therefore, also with the electromagnetically driven valve 80 of the present embodiment, it is possible to achieve excellent accuracy in the opening / closing timing of the valve body 12 as in the case of the first or second embodiment.

By the way, the first to third embodiments described above
Is limited to the case where the valve body 12 of the electromagnetically driven valves 10 and 80 is an exhaust valve, but the present invention is not limited to this. That is, the electromagnetically driven valves 10 and 80 may be used as an intake valve and a drive mechanism thereof.

[0062]

Since the present invention is constructed as described above, it has the following effects. Claim 1
According to the invention described above, since the contact surface between the armature and the electromagnet is covered with the oil-repellent film, most of the lubricating oil that has reached the contact surface from the wet holding unit flows down as oil droplets. Therefore, according to the present invention, it is possible to effectively prevent formation of an oil film on the contact surface between the armature and the electromagnet, which hinders the separation between the armature and the electromagnet, and to realize excellent control accuracy regarding the opening / closing timing of the valve element. it can.

According to the second aspect of the invention, the surface of the armature can be covered with the fluorocarbon layer having excellent oil repellency. Further, in the present invention, the strength and adhesion of the fluorocarbon layer can be enhanced by interposing the silane coupling layer. Therefore, according to the present invention,
The surface of the armature can be covered with an oil-repellent film that has excellent oil repellency and is highly reliable and durable.

According to the third aspect of the invention, the surface of the armature can be covered with the methylhydrogensiloxane layer. The methylhydrogensiloxane layer is a layer having excellent oil repellency and exhibiting high strength on an inorganic material containing silicon. Therefore, according to the present invention, the surface of the armature can be covered with an oil-repellent film which is excellent in oil repellency and also excellent in reliability and durability.

According to the fourth aspect of the invention, since the cushioning material is arranged between the electromagnet and the holding block, it is possible to realize an electromagnetically driven valve excellent in quietness.

According to the fifth aspect of the invention, the carbon relief is positioned outside the valve guide when the electromagnetically driven valve is stopped. Therefore, according to the present invention, it is possible to realize an electromagnetically driven valve having good startability by avoiding carbon deposition and adhesion in the valve guide while the electromagnetically driven valve is stopped.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a configuration of an electromagnetically driven valve according to a first or second embodiment of the present invention.

FIG. 2 is an enlarged view showing the periphery of a valve shaft included in the electromagnetically driven valve shown in FIG.

FIG. 3 is a diagram for explaining a structure of an armature included in the electromagnetically driven valve shown in FIG.

FIG. 4 is a diagram showing a structure of an armature included in the electromagnetically driven valve according to the first embodiment of the present invention at a molecular level.

FIG. 5 is a diagram showing a structure of an armature included in the electromagnetically driven valve according to the second embodiment of the present invention at a molecular level.

FIG. 6 is a diagram for explaining a structure of an electromagnetically driven valve according to a third embodiment of the present invention.

[Explanation of symbols]

10; 80 Electromagnetically driven valve 12 valve bodies 18 valve shaft 20 Valve guide 28 Armature axis 30 Armature 38 Lower Core 40 lower coil 42 Lower electromagnet 44 Upper core 46 Upper coil 48 upper electromagnet 50,52 Wet bush 58; 94 cushioning material 60 carbon relief 62 Oil drain groove 64 Magnetic part 66 Oil repellent coating 68 Silane coupling layer 70 Fluorocarbon layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02K 33/12 H02K 33/12 (72) Inventor Hideyuki Nishida 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Corporation Company (72) Inventor Isao Matsumoto 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Tashun Mizuta 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Keiji Sieda 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. (72) Inventor Masato Ogiso 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. F Term (reference) 3G018 AB08 AB09 BA38 CA12 DA00 DA41 DA70 DA81 FA01 FA07 GA02 GA04 GA11 GA23 GA32 3H106 DA07 DA25 DB02 DB12 DB26 DB32 DC02 EE24 EE48 GA15 GA22 KK17 5H633 BB07 BB10 GG02 GG 05 GG06 GG09 GG13 HH17 HH20 HH24 JA02 JA05 JB05

Claims (5)

[Claims] 1. An electromagnetically driven valve that opens and closes a valve body by electromagnetic force, comprising: an electromagnet that generates the electromagnetic force; an armature that faces the electromagnet; and an armature shaft that is fixed to the armature. , Using a lubricating oil so that the state where the armature and the electromagnet are in contact with each other and the state where they are separated can be realized,
An electromagnetically driven valve, comprising: a wet holding part that slidably holds the armature shaft; and an oil-repellent coating formed on a contact surface between the armature and the electromagnet. 2. The armature includes a magnetic portion formed of a magnetic material containing silicon, and the oil repellent coating includes a fluorocarbon layer and a silane coupling layer for coupling the fluorocarbon layer and the magnetic portion. The electromagnetically driven valve according to claim 1, comprising: 3. The electromagnetically driven valve according to claim 1, wherein the armature includes a magnetic portion formed of a magnetic material containing silicon, and the oil-repellent coating includes a methylhydrogensiloxane layer. 4. The holding block for holding the electromagnet, and a cushioning material interposed between the electromagnet and the holding block, according to any one of claims 1 to 3. Electromagnetically driven valve. 5. A valve shaft fixed to the valve body, and a valve guide that slidably holds the valve shaft, wherein the valve shaft slides on an inner wall of the valve guide. Between the valve body, a carbon relief that makes the valve shaft thinner than the sliding portion, the carbon relief, when the electromagnetically driven valve is stopped,
The electromagnetically driven valve according to any one of claims 1 to 4, wherein the electromagnetically driven valve is formed so as to be located outside the valve guide.