JPH09151716A - Valve of magnetic system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain both sure valve closing action and minimization of a clearance between a plunger and a magnetic field producing member, even by generating a little change of shape due to thermal expansion, wearing, etc. SOLUTION: Assuming contact of a plunger 6 with an upper side magnetic field producing member 7 without seating a valve element 1 in a valve seat 3 by thermal expansion or the like of a valve shaft 4, by a slope direction component of magnetic force attracting the plunger 6, it is rotated in the direction of arrow mark, seating of the valve element 1 is attained. On the other hand, regardless of seating of the valve element 1 in the valve seat 3, in the case of providing a clearance between the plunger 6 and the upper side magnetic field producing member 7, by force attracting together by the fellow slopes of the plunger 6 and the upper side magnetic field producing member 7, the plunger 6 is rotated in the reverse direction, so as to make the clearance zero.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake / exhaust valve for an internal combustion engine, and more particularly to a magnetic valve for controlling its drive by using magnetic force.

[0002]

2. Description of the Related Art Conventionally, as an intake / exhaust valve of an internal combustion engine, a valve which is opened / closed by a camshaft driven based on rotation of a crankshaft is generally used. And
From the viewpoint of improving the performance of an internal combustion engine, various variable mechanisms of a valve operating system are being put into practical use in order to achieve an optimal valve opening / closing timing according to an operating state.
/ OFF control type) and continuously variable types have also been developed. These variable mechanisms include those that shift the rotation phase of the camshaft and those that have a plurality of cam profiles on the camshaft.

However, in the intake / exhaust valve driven by the camshaft as described above, it is impossible to independently and arbitrarily set the valve lift amount, the valve opening time, and the opening / closing timing. Therefore, in recent years, in order to meet the demand for higher performance of the internal combustion engine, research on an electromagnetically driven valve train that can set those parameters to ideal values according to the operation state has been activated. I have.
For example, JP-A-61-248402 discloses an example of such an electromagnetically driven intake / exhaust valve. In the solenoid valve, the valve closing operation is performed by attracting the plunger connected to the valve body to the core by the electromagnetic force.

[0004]

By the way, in the above publication, there is a description that a magnetoresistive layer is formed on the surface of the plunger. In this prior art, a valve body and a valve seat (valve seat) are provided. It is considered that the contact with the core and the contact between the plunger and the core are made at the same time. However, when the internal combustion engine is operating, due to thermal expansion of the valve shaft and wear between the valve body and valve seat, the plunger and core come into contact with each other before the time when the valve body and valve seat come into contact, and the valve closes. The valve may be blocked. On the other hand, if the clearance between the plunger and the core is increased to prevent such an inconvenience, there arises a problem that the electric power required to maintain the valve closed state increases.

In view of such circumstances, an object of the present invention is to achieve both a reliable valve closing operation and a minimum clearance between the plunger and the magnetic field generating member even if there is a slight change in shape due to thermal expansion, wear or the like. (EN) Provided is a magnetic valve for an internal combustion engine.

[0006]

A magnetic valve for an internal combustion engine according to the present invention devised to achieve the above object holds a valve in a closed position by magnetically attracting a plunger. In the magnetic valve of the engine, the plunger on the suction side has a plurality of slopes inclined in the circumferential direction,
A magnetic field generating member having a plunger receiving surface corresponding to the plurality of slopes.

In the magnetic valve of the internal combustion engine constructed as described above, the valve shape changes due to thermal expansion, wear, etc.
Whichever comes first, the contact time between the valve body and the valve seat and the contact time between the plunger and the magnetic field generation member, the plunger and the plunger receiving surface of the magnetic field generation member form an inclined surface in the circumferential direction. The magnetic attraction and rotation in the direction of the magnetic field generating member achieves a reliable valve closing operation and a minimum clearance between the plunger and the core.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a magnetic valve of an internal combustion engine according to an embodiment of the present invention. Valve element 1 shown in FIG.
The seat opens or closes the intake / exhaust port 2 by sitting on or separated from the valve seat 3 provided in the intake / exhaust port 2 of the internal combustion engine. A valve shaft 4 is fixed to the valve body 1. The valve shaft 4 is held by a valve guide 5 so as to be slidable in the axial direction. A plunger 6 is fixed to the valve shaft 4. The plunger 6 is a disk-shaped member made of a soft magnetic material. Above the plunger 6, an upper side magnetic field generating member 7 is separated by a predetermined distance, and below the plunger 6, a lower side magnetic field generating member 8 is similarly separated by a predetermined distance. It is arranged.

The upper magnetic field generating member 7 is composed of an upper core (u
The lower side magnetic field generating member 8 is composed of a lower core and a lower coil.
It is composed of a (lower core) 81 and a lower coil 82. The upper core 71 and the lower core 81 are made of a soft magnetic material, and are held in a predetermined positional relationship by the case 9 made of a non-magnetic material. The upper core 71 holds the upper coil 72, and the lower core 81 holds the lower coil 82.

The valve shaft 4 has an upper spring 10
The lower spring 11 elastically supports the lower spring 11 in the axial direction. Then, the upper side spring 10 is adjusted so that the position (neutral position) of the plunger 6 when the upper coil 72 and the lower coil 82 are not energized is an intermediate position between the upper side magnetic field generating member 7 and the lower side magnetic field generating member 8. And the lower side spring 11 are balanced. When the plunger 6 is in the neutral position, the valve body 1 is located at an intermediate position between the fully open side displacement end and the fully closed side displacement end.

According to this structure, a magnetic circuit including the upper core 71, the plunger 6, and the air gap formed between the upper core 71 and the plunger 6 is formed around the upper coil 72. Therefore, when an electric current is passed through the upper coil 72, the magnetic flux is circulated in the magnetic circuit, and a magnetic force is generated in the direction of reducing the air gap, that is, in the direction of displacing the plunger 6 upward.

On the other hand, a magnetic circuit including a lower core 81, a plunger 6, and an air gap formed between the lower core 81 and the plunger 6 is formed around the lower coil 82. Therefore, when a current is applied to the lower coil 82, a magnetic force is generated in the direction of displacing the plunger 6 downward based on the same principle.

Thus, by alternately passing a current through the upper coil 72 and the lower coil 82, it becomes possible to reciprocate the plunger 6 up and down, that is, to drive the valve body 1 alternately in the opening and closing directions.

When the valve is held in the closed state, the upper coil 72 is energized to generate a magnetic force and the plunger 6 is attracted to the upper magnetic field generating member 7 side.
The smaller the clearance between the upper magnetic field generation member 7 and the plunger 6, the more the power consumption can be reduced. However, if you set this clearance to zero,
Due to thermal expansion of the valve and the like, the plunger 6 and the upper magnetic field generating member 7 come into contact with each other before the valve body 1 and the valve seat 3 come into contact with each other, so that the valve body 1 cannot be seated on the valve seat 3. As a result, the airtightness of the internal combustion engine may not be maintained. Therefore, it is necessary to set the clearance between the plunger 6 and the upper magnetic field generation member 7 to a certain value or more, resulting in an increase in power consumption.

Therefore, in the present invention, the upper surface of the plunger 6 is provided with a plurality of slopes, that is, N slopes as shown in FIG.
The upper surface side magnetic field generating member 7 has the same shape as the lower surface. Note that FIG. 2 shows a case where N = 6.

R coordinate axis in the radial direction of the valve shaft and θ in the circumferential direction of the valve shaft.
If the z coordinate axis is taken in the coordinate axis and the valve axis direction, that is, the cylindrical coordinate (r, θ, z) as shown in FIG. 3 is adopted, and the number of slopes is N and the height of the slope is H, then the slope described above. Is expressed in detail as follows. However, the z coordinate of the bottom end of the slope is set to 0, and the θ coordinate of the bottom end of a certain slope is set to 0.

When 0 <θ ≦ T z = H × (θ / T) T <θ ≦ 2T z = H × [(θ−T) / T] 2T <θ ≦ 3T z = H × [(Θ-2T) / T] :: :: (N−1) T <θ ≦ NT z = H × [{θ− (N−1) T} / T] where T = 360 / N

As described above, z (0.ltoreq.z.ltoreq.H) is a function that does not depend on r but only on .theta., And the relationship between .theta. And z is as shown in FIG. .

Further, in this embodiment, when the length from the plunger 6 to the valve body 1 is the shortest during cold and shipping, as shown in FIG. The uppermost end of the inclined surface of the plunger 6 is set so as to come into contact with the vicinity of the center of the inclined surface of the upper magnetic field generation member 7 when seated on the.

It is assumed that the valve shaft 4 is thermally expanded after the initial state is set. In this case, if the plunger 6 and the upper magnetic field generating member 7 contact each other without the valve body 1 being seated, the slope direction component of the magnetic force that attracts the plunger 6 causes the plunger 6 to move in the direction of the arrow shown in FIG. Will rotate, and as a result, the valve body 1
Is seated on the valve seat 3. In that case, the force in the rotation direction can be increased by decreasing the friction coefficient between the plunger 6 and the upper magnetic field generating member 7, increasing the slope height H, and increasing the slope number N. Is.

On the other hand, in the case where the valve body 1 is seated on the valve seat 3 due to recovery from thermal expansion of the valve shaft 4 or the like, there is a clearance between the plunger 6 and the upper magnetic field generating member 7. Think In this case, the force of attraction between the slopes of the plunger 6 and the upper magnetic field generation member 7 causes the plunger 6 to rotate in the direction of the arrow shown in FIG. 7, resulting in zero clearance. .
At this time, the force in the rotation direction can be increased by applying or plating a substance having a low magnetic permeability on the vertical surface of the plunger 6 and the vertical surface of the upper magnetic field generation member 7.

As described above, the structure of this embodiment always realizes both reliable seating of the valve element and minimization of the clearance between the plunger and the upper magnetic field generating member.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, of course.
It will be easy for those skilled in the art to devise various embodiments. For example, the upper magnetic field generating member of this embodiment may be a permanent magnet. Further, the lower magnetic field generating member and the lower spring of this embodiment may be omitted. If the height H of the slope is set to a large value, changes over time due to wear of the valve seat and the like can be absorbed, so that the performance at the time of shipment and power consumption can be maintained for a long period of time.

[0025]

As described above, according to the present invention,
Provided is a magnetic valve for an internal combustion engine capable of achieving both a reliable valve closing operation and a minimum clearance between a plunger and a magnetic field generating member even if there is a slight change in shape due to thermal expansion, wear, or the like. .

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a magnetic valve of an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a structure of a plunger.

FIG. 3 is a diagram for explaining cylindrical coordinates.

FIG. 4 is a diagram for explaining the shape of the slope of the plunger using cylindrical coordinates.

FIG. 5 is a diagram for explaining an initial setting state of a plunger and an upper magnetic field generation member.

FIG. 6 is a diagram for explaining the rotation of the plunger 6 when the plunger 6 and the upper magnetic field generation member 7 contact each other before the valve body 1 is seated.

FIG. 7 is a diagram for explaining the rotation of the plunger 6 when the valve body 1 is seated before the contact between the plunger 6 and the upper magnetic field generation member 7.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Valve body 2 ... Intake / exhaust port of internal combustion engine 3 ... Valve seat 4 ... Valve shaft 5 ... Valve guide 6 ... Plunger 7 ... Upper side magnetic field generation member 71 ... Upper core 72 ... Upper coil 8 ... Lower side magnetic field generation member 81 ... Lower core 82 ... Lower coil 9 ... Case 10 ... Upper side spring 11 ... Lower side spring

Claims (1)

[Claims] 1. A magnetic valve for an internal combustion engine, wherein a valve is held in a closed position by attracting the plunger with a magnetic force, the plunger having a plurality of slopes on the suction direction side, the plurality of slopes being inclined in the circumferential direction, And a magnetic field generating member having a plunger receiving surface corresponding to the slope of the magnetic valve of the internal combustion engine.