JPH09303599A - Valve system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distinguish eddy current generated around cores in the early stage in connection with the valve system which drives the intake valve or the exhaust valve of an internal combustion engine by electromagnetic force. SOLUTION: A first core 34 holding a first electromagnetic coil 32 and a second core 38 holding a second electromagnetic coil 36 are disposed while being parted by a specified distance. A magnetic plate 30 to be connected with a valve body 12, is interposed between the first core 34 and the second core 38. A first slit which is extended from one end face to the other end face, and a second slit which is extended from the other end face to one end face, are provided for the first core 34 and the second core 38 respectively. The first and second slits are so provided that they donot penetrate through the first and second cores 34 and 38 in the axial direction, and however they are overlapped with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating system for an internal combustion engine, and more particularly to a valve operating system for an internal combustion engine suitable for driving 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-2-17628
As disclosed in No. 8, there is known a device that drives a valve element included in an internal combustion engine by electromagnetic force. The conventional device described above includes a disc-shaped plunger fixed to the valve body. In the above-mentioned conventional device, a first electromagnetic coil and a first electromagnetic coil surrounding the first electromagnetic coil are provided on an upper portion of the plunger.
And a core. In addition, a second electromagnetic coil and a second electromagnetic coil surrounding the second electromagnetic coil are provided under the plunger.
And a core.

The first core, the plunger, and the air gap formed between the first core and the plunger form a magnetic circuit surrounding the inside and outside of the first electromagnetic coil. When an electric current is supplied to the first electromagnetic coil, the magnetic flux generated by the first electromagnetic coil passes through the magnetic circuit to generate the first magnetic flux.
Circulates inside and outside the electromagnetic coil. At this time, the electromagnetic attraction force that acts toward the first core acts on the plunger.

Also, the second core, the plunger, and the second
The air gap formed between the core and the plunger is
A magnetic circuit surrounding the inside and outside of the second electromagnetic coil is formed. When an electric current is supplied to the second electromagnetic coil, the magnetic flux generated by the second electromagnetic coil circulates inside and outside the second electromagnetic coil through the above magnetic circuit. At this time, the electromagnetic attraction force that acts toward the second core acts on the plunger.

According to the above construction, by supplying the current to the first electromagnetic coil, the plunger, that is, the valve body can be displaced to the first core side, and the current is supplied to the second electromagnetic coil. By supplying the plunger,
That is, the valve body can be displaced to the second core side. Therefore, according to the above-mentioned conventional device, the valve body can be opened and closed by alternately supplying currents to the first electromagnetic coil and the second electromagnetic coil at appropriate timings.

[0006]

By the way, in the above-mentioned conventional device, in order to attract and hold the plunger to the first core side, it is necessary to keep the current flowing through the first electromagnetic coil. At this time, the magnetic flux flowing through the first core converges to a predetermined value according to the value of the current I flowing through the first electromagnetic coil. In order to displace the plunger toward the second core from such a state, it is necessary to extinguish the magnetic flux flowing through the first core before starting to supply the second electromagnetic coil with current.

The magnetic flux flowing through the first core disappears after a predetermined delay time elapses after stopping the supply of the current to the first electromagnetic coil. That is, when the current supply to the first electromagnetic coil is stopped under the condition that the magnetic flux flowing through the first core is converged to a predetermined value, the first core is affected by the electromagnetic induction in the direction in which the magnetic flux is prevented from decreasing. Eddy current is generated. Therefore, the magnetic flux flowing through the first core disappears after the time required to eliminate the eddy current elapses after the supply of the current to the first electromagnetic coil is stopped.

Similarly, after the supply of the current to the second electromagnetic coil is started, the magnetic flux flowing through the second core converges to a predetermined value after a predetermined delay time has elapsed. That is, the second
When the supply of the current to the electromagnetic coil is started and the magnetic flux starts to flow through the second core, an eddy current due to electromagnetic induction is generated in the second core in a direction in which the increase of the magnetic flux is prevented. Therefore, the magnetic flux flowing through the second core converges to a predetermined value after the time required for extinction of the eddy current elapses after the supply of the current to the second electromagnetic coil is started.

In order to ensure excellent responsiveness in the valve train of the internal combustion engine, after the supply of the current to the first or second electromagnetic coil is stopped or after the supply of the current is started, It is necessary to quickly extinguish the eddy current generated in the first or second core. For the time until the eddy currents generated in the first and second cores disappear, for example, the first and second cores are provided with slits extending in their radial directions and penetrating them axially. It can be shortened. That is, when the slit is formed, the eddy current cannot flow back around the central axes of the first and second cores, and the flow path of the eddy current is substantially extended as compared with the case where the slit does not exist. . As a result, the first
When the slit is formed in the second core, the eddy current generated by the electromagnetic induction is likely to be consumed as resistance heat early. Therefore, by adding the above-mentioned slits to the first core and the second core included in the above-described conventional valve operating device, it is possible to realize a valve operating device with better responsiveness.

However, if the first core and the second core are provided with slits extending in the radial direction of the first core and penetrating them axially, the rigidity of the first core and the second core is ensured. Will be difficult to do. Therefore, simply adding the slit to the core cannot solve the problem caused by the eddy current while ensuring the rigidity required for the core.

The present invention has been made in view of the above points, and a valve operating device for an internal combustion engine that solves the above problems by providing slits in the core in an arrangement that can ensure its rigidity. The purpose is to provide.

[0012]

The object of the present invention is to provide an internal combustion engine including a core for holding an electromagnetic coil and a plunger attracted to the core side by supplying an exciting current to the electromagnetic coil. In the valve device, the core includes a first slit and a second slit extending from both axial end faces toward the other end face, and the first slit and the second slit form the core. This is achieved by a valve train of an internal combustion engine that is provided so as not to penetrate in the axial direction and to overlap each other.

In the present invention, when a current is supplied to the electromagnetic coil, a magnetic field that circulates inside and outside the electromagnetic coil is generated, and the magnetic flux flows through the core and the plunger. When the magnetic flux flowing through the core increases or decreases, an eddy current that flows back in a plane perpendicular to the axial direction is generated in the core by electromagnetic induction so that the change in the magnetic flux is suppressed. The plane in which the eddy current flows inside the core is divided into a plurality of regions by the first and second slits provided so as to overlap each other at any portion in the axial direction. Therefore, the eddy current cannot flow back around the central axis of the core in the shortest path. The longer the flow path of the eddy current, the easier it is to disappear as resistance heat. Therefore, according to the structure in which the eddy current cannot flow back in the shortest path, it is possible to form an advantageous situation for promptly extinguishing the eddy current. By the way, the first slit and the second slit are
Both are formed so as not to penetrate the core in the axial direction.
For this reason, the core has high rigidity even though the plane in which the eddy current flows is divided into a plurality of regions at any part of the core in the axial direction.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall configuration of a valve train 10 which is an embodiment of the present invention. The valve train 10 includes a valve body 12. The valve body 12 is a member 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. The cylinder head of the internal combustion engine is provided with a port having a valve seat for the valve body 12. Valve body 12
Is separated from or seated on the valve seat to control the conduction state of the port.

A valve shaft 14 is fixed to the valve body 12. The valve shaft 14 is held by a valve guide 16 so as to be slidable in the axial direction. The valve guide 16 is supported by the lower cap 17 of the valve gear 10. A plunger holder 18 is fixed to the upper portion of the valve shaft 14. The plunger holder 18 is made of a material having high hardness such as non-magnetic property or low magnetic property such as stainless steel or titanium alloy. The plunger holder 18 is the valve shaft 1
4 includes a cylindrical portion 18a extending in the axial direction and a ring portion 18b formed at a substantially central portion of the cylindrical portion 18a in the axial direction.

A lower retainer 20 is fixed to the lower end of the plunger holder 18. A lower spring 22 is disposed between the lower retainer 20 and the lower cap 17 to generate an urging force in a direction to separate the lower retainer 20 and the lower cap 17.
The lower spring 22 biases the lower retainer 20, that is, the plunger holder 18 upward in FIG. 1.

On the other hand, an upper retainer 24 is fixed to the upper end of the plunger holder 18. The lower end of the upper spring 26 is in contact with the upper part of the upper retainer 24. A cylindrical upper cap 27 is provided around the upper spring 26 so as to surround the outer periphery thereof. Furthermore, the upper spring 2
The upper end of 6 is in contact with an adjusting bolt 28 screwed to the upper cap 27. The upper spring 26 urges the upper retainer 24, that is, the plunger holder 18 downward in FIG. 1.

The ring portion 18b of the plunger holder 18
A plunger 30 is joined to the outer periphery of the. The plunger 30 is a doughnut-shaped member made of a soft magnetic material having Fe, Ni, Co or the like as a base material. The plunger 30 and the plunger holder 18 are joined by a method such as electron beam welding, laser welding, brazing, caulking, or bonding.

A first electromagnetic coil 32 and a first core 34 are arranged above the plunger 30. A second electromagnetic coil 36 and a second core 38 are arranged below the plunger 30. The first core 34 and the second core 38 are both members made of a magnetic material, and have annular grooves 34a and 38a for accommodating the first electromagnetic coil 32 or the second electromagnetic coil 36, respectively, and their central portions. Through holes 34b and 38b penetrating in the axial direction.

FIG. 2 shows a front view of the first core 34. 3 is a view showing the first core 34 in the direction of arrow III shown in FIG. 2, and FIG. 4 is obtained when the first core 34 is cut along the line IV-IV shown in FIG. A cross-sectional view is shown in FIG.
Shows a view of the first core 34 as seen from the direction of the arrow V shown in FIG.

As shown in FIG. 2, the first core 34 has a groove 34.
c, the first slit 34d, and the second slit 34e
It has. The groove 34c is provided so as to penetrate the first core 34 in the axial direction. The first slit 34d and the second slit 34e are provided so as to extend from the upper end surface or the lower end surface of the first core 34 toward the other end surface to a position where they overlap each other.

As shown in FIGS. 3 to 5, the groove 34c extends in the radial direction of the first core 34 and is provided so as to communicate with the through hole 34d. The groove 34c is formed by the first electromagnetic coil 3
It is used as a space to house the terminal connected to the two windings. That is, the first electromagnetic coil 32 has the first core 34 so that its terminal fits in the groove 34c.
It is housed in the annular groove 34a.

As shown in FIG. 3, the first core 34 has three first slits 34d. First slit 34d
Are provided so as to extend in the radial direction of the first core 34 similarly to the groove 34c. Also, the three first slits 34
d is 90 °, 180 °, 270 from the groove 34c, respectively.
The phase shifter is provided so as to communicate with the through hole 34d. The first core 34d is divided into four fan-shaped regions by the groove 34c and the first slit 34e.

As shown in FIG. 5, the first core 34 has four second slits 34e. Second slit 34e
Are provided so as to extend in the radial direction of the first core 34 similarly to the groove 34e. Also, the four first slits 34
d is 45 °, 135 °, 225 from the groove 34c, respectively.
It is provided so as to communicate with the through hole 34d at a position shifted in phase by 315 °. The first core 34 has a groove 34c.
And it is divided into five fan-shaped regions by the second slit 34e.

FIG. 4 shows the first slit 34d and the first slit 34e at the position where they overlap each other.
A sectional view of the core 34 is shown. As shown in FIG. 4, in the region where the first slit 34d and the second slit 34e overlap, the inner peripheral side and the outer peripheral side of the annular groove 34a of the first core 34 are the groove 34c, the first slit 34d, and the first slit 34d. Each of the two slits 34e divides it into eight fan-shaped regions.

As described above, the first core 34 included in the valve gear 10 is divided into a plurality of fan-shaped regions by the groove 34c, the first slit 34d, and the second slit 34e. The second core 38 included in the valve gear 10 includes a groove corresponding to the groove 34c, the first slit 34d, and the second slit 34e described above, a first slit, and a second slit. The second core 38, like the first core 34, is divided into a plurality of fan-shaped regions by the groove, the first slit, and the second slit. In the following description, the grooves, the first slits, and the second slits included in the second core 38 are denoted by reference numerals 38c, 38d, and 38e for convenience.

As shown in FIG. 1, the through hole 3 of the first core 34
The first bearing 4 is provided at one end (upper end in FIG. 1) of 4b.
0 is provided. In addition, the through hole 38 of the second core 38
The second bearing 42 is provided at one end (lower end in FIG. 1) of b.
Are arranged. Cylindrical portion 18 of plunger holder 18
a is slidably held by the first bearing 40 and the second bearing 42.

An outer cylinder 44 is arranged around the outer peripheries of the first core 34 and the second core 38. The first core 34 and the second core 38 are held by an outer cylinder 44 so that a predetermined space is secured between them. The upper cap 27 described above is fixed to the upper end surface of the first core 34. On the other hand, the lower cap 17 described above is fixed to the lower end surface of the second core 38. In the adjuster bolt 28 described above, the neutral position of the plunger 30 is
It is adjusted to be an intermediate point between the first core 34 and the second core 38.

The operation of the valve operating system 10 will be described below. A current is applied to the first electromagnetic coil 32 and the second electromagnetic coil 36 (hereinafter referred to as the first electromagnetic coil 32 or the second electromagnetic coil 3).
6 is not flowing, the plunger 30 is in its neutral position, that is, the first position.
It is maintained between the core 34 and the second core 38. When the supply of the exciting current to the first electromagnetic coil 32 is started in the state where the plunger 30 is maintained in the neutral position, a magnetic field that circulates in the inner and outer circumferences is generated around the first electromagnetic coil 32.

This magnetic field is generated by the inner circumference of the first core 34 → air gap → plunger 30 → air gap → first core 3
4, a magnetic flux that recirculates is generated by following the flow path represented by the outer peripheral side of 4 → the inner peripheral side of the first core 34, or the reverse flow path. Further, when the magnetic flux that recirculates along the above-described circulation path is generated, an electromagnetic force that attracts the plunger 30 to the first core 34 side is generated so that the air gap between the first core 34 and the plunger 30 becomes small. To do.

When the above-mentioned electromagnetic force acts on the plunger 30, the plunger 30, the plunger holder 18, the upper retainer 24, the lower retainer 20, the valve shaft 14 and the valve body 12 (hereinafter collectively referred to as the movable portion 50). )
Is displaced upward in FIG. 1 against the urging force of the upper spring 26. Then, the displacement is continued until the plunger 30 comes into contact with the first core 34. Hereinafter, the position where the plunger 30 contacts the first core 34
It is referred to as the plunger 30, the movable portion 50, or the valve closing side displacement end of the valve body 12.

When the supply of the exciting current to the first electromagnetic coil 32 is stopped while the plunger 30 is held at the valve closing side displacement end, the plunger 30 is then maintained at the valve closing side displacement end. The required electromagnetic force disappears. When the electromagnetic force disappears, the movable portion 50 starts to be displaced downward in FIG. 1 by being urged by the upper spring 26. When an appropriate exciting current is passed through the second electromagnetic coil 36 at the time when the displacement amount of the movable portion 50 reaches a predetermined value, the electromagnetic force for attracting the plunger 30 to the second core 38 side, that is, the valve body An electromagnetic force that displaces 12 downward in FIG. 1 is generated.

When the above electromagnetic force acts on the plunger 30, the movable portion 50 is displaced against the urging force of the lower spring 22 until the plunger 30 contacts the second core 38. Hereinafter, the position where the plunger 30 comes into contact with the second core 38 is referred to as the plunger 30, the movable portion 50, or the valve opening side displacement end of the valve body 12. Therefore, according to the valve operating system 10 of the present embodiment, the valve body is alternately supplied to the first electromagnetic coil 32 and the second electromagnetic coil 36 at an appropriate timing and with an appropriate magnitude. 12 can be repeatedly reciprocated between the valve-opening side displacement end and the valve-closing side displacement end.

By the way, in driving the valve operating device 10, when the supply of the exciting current to the first electromagnetic coil 32 or the second electromagnetic coil 36 is started, the magnetic field surrounding the first core 32 or the second core 38 is changed. The environment changes rapidly. When the plunger 30 is displaced due to a change in the magnetic field environment, the magnetic resistance of the magnetic circuit including the core decreases as the plunger 30 approaches the first core 32 or the second core 38. First core 32 or second core 3
The magnetic flux flowing through 8 increases as the magnetic resistance of the magnetic circuit decreases. Therefore, when the exciting current starts to be supplied to the first electromagnetic coil 32 or the second electromagnetic coil 36, the magnetic flux flowing through the first core 34 or the second core 38 thereafter changes the magnetic field environment and the magnetic field. Due to the change in resistance, it shows a change over time.

When the exciting current flowing through the first electromagnetic coil 32 or the second electromagnetic coil 36 is cut off, the environment of the magnetic field surrounding the first core 34 or the second core 38 suddenly changes before and after that. Therefore, when the exciting current supplied to the first electromagnetic coil 32 or the second electromagnetic coil is stopped, the magnetic flux flowing through the first core 34 or the second core 38 after that is caused by the change in the magnetic field environment. Shows the change over time.

As described above, the first core 34 and the second core 38 are supplied to the first electromagnetic coil 32 immediately after the supply of the exciting current to the first electromagnetic coil 32 is started or stopped, or the second electromagnetic coil 3 is supplied.
Immediately after the supply of the excitation current to 6 has been started or stopped,
A magnetic flux whose strength changes over time flows. First core 34
The second core 38 is made of a conductive material. Therefore, when the magnetic flux passing through them changes with time, an eddy current is generated in the first core 34 and the second core 38 to flow back in a direction in which the magnetic flux change is suppressed by electromagnetic induction. .

FIG. 6 shows the direction of the eddy current 54 generated in the ring-shaped conductor 52 by the back electromotive force when the magnetic flux Φ penetrating the ring-shaped conductor 52 from the front side to the back side of the paper decreases temporally. . When the magnetic flux Φ penetrating the annular conductor 52 from the front side to the back side of the drawing decreases, the annular conductor 52 has
An eddy current that advances in a direction that prevents the decrease, that is, a clockwise direction in FIG. 6, is generated. The annular conductor 52
When the above-mentioned magnetic flux Φ penetrating the arrow increases with time, an eddy current that advances in the counterclockwise direction in FIG. 6 is generated.

In this embodiment, the groove 3 is formed in the first core 34.
4c, the first slit 34d, and the second slit 34
If e is not formed, that is, the first core 3
If 4 has uniform magnetism over the entire circumference, immediately after the supply of the exciting current to the first electromagnetic coil 32 is started and immediately after the supply of the exciting current is stopped, As in the case of the annular conductor 52 shown in FIG.
An eddy current that flows back around the entire circumference of the core 34 is generated. Similarly,
If the groove 38c, the first slit 38d, and the second slit 38e are not formed in the second core 38,
Immediately after the supply of the exciting current to the second electromagnetic coil 36 is started, and immediately after the supply of the exciting current is stopped,
An eddy current that flows around the entire circumference of the second core 38 is generated.

As described above, the eddy current generated in the first core 34 or the second core 38 has an effect of preventing the change of the magnetic flux flowing inside the first core 34 or the second core 38. If the change of the magnetic flux flowing through the first core 34 and the second core 38 is hindered, the responsiveness of the valve gear 10 is deteriorated and the energy consumption characteristic of the valve gear 10 is deteriorated. For this reason, it is desirable that the first core 34 and the second core 38 have a characteristic capable of extinguishing the eddy current at an early stage.

FIG. 7 shows a magnetic flux Φ penetrating the annular conductor 56 having four slits 56a from the front side to the back side of the paper.
Indicates the direction of the eddy current 58 generated inside the annular conductor 56 by electromagnetic induction when the time decreases with time. Since the slit 56a is formed in the ring-shaped conductor 56, the eddy current generated in the ring-shaped conductor 56 cannot flow all around.

As a result, when the magnetic flux Φ decreases, the annular conductor 56 advances in the clockwise direction on the outer peripheral side of each of the regions separated by the slit 56a in FIG. 7, and An eddy current that advances in the counterclockwise direction in FIG. When the magnetic flux Φ increases, the outer peripheral side of each of the regions separated by the slit 56a travels counterclockwise in FIG. 7, and the inner peripheral side of FIG. An eddy current that advances in the clockwise direction is generated.

The total sum of the eddy current flow paths shown in FIG. 7 is a long distance compared to the total length of the eddy current flow paths shown in FIG. Eddy currents generated by electromagnetic induction are extinguished by being converted into resistive heat in the course of the flow. Therefore, the eddy current disappears earlier as the circulation path becomes longer. In this respect, the annular conductor 56 having the slit 56a
In terms of extinguishing the eddy current at an early stage, has excellent characteristics as compared with the annular conductor 52 having no slit.

As described above, in order to quickly eliminate the eddy current flowing back inside the ring-shaped conductor (the eddy current flowing back in the plane perpendicular to the axial direction of the conductor), the ring-shaped conductor is required. In addition, it is effective to provide a slit extending in the radial direction. Therefore, if the first core 34 and the second core 38, which are annular conductors included in the valve gear 10, are provided with slits extending in the radial direction thereof, the first core 34 and the second core 38, It is possible to impart excellent characteristics to the early elimination of the eddy current.

By the way, the first core 34 and the second core 3
Even if a slit extending in the radial direction with respect to 8 is provided, if an area where none of the slits extends remains for a long time, the eddy current generated in that area cannot be promptly extinguished. Therefore, when providing the slits for the first core 34 and the second core 38, it is desirable to make the region in which none of the slits extends as short as possible.

The above requirement can also be satisfied by providing the first core 34 and the second core 38 with slits having a length substantially equal to their axial lengths. However, when such a slit is provided, the rigidity of the first core 34 and the second core 38 is significantly reduced,
Various adverse effects occur on the workability of assembling, the durability of the valve train 10, and the like. Therefore, it is not always appropriate to increase the length of each slit to satisfy the above requirement in order to secure the overall performance of the valve train 10. Therefore, in the present embodiment, the first slits 34d and 38d and the second core 38 and the second core 38 are provided.
The above requirements are satisfied by providing the slits 34e and 38e.

That is, as described above, the first slit 34
The d and 38d and the second slits 34e and 38e are designed to have a distance sufficiently shorter than the axial length of the first core 34 or the second core 38 so as not to penetrate the first core 34 or the second core 38, respectively. Has been done. Therefore, the first core 3
Sufficient rigidity is imparted to the fourth and second cores 38. Further, as described above, the first slits 34d, 38d and the second slits 34e, 38e are designed so that they sufficiently overlap each other. For this reason, the cross sections of the first core 34 and the second core 38 are divided into at least four regions at any part in the axial direction.

As described above, according to the structure of the present embodiment, the early eddy current is generated in the first core 34 and the second core 38 without lowering the rigidity of the first core 34 and the second core 38. It is possible to provide advantageous characteristics for extinction. Therefore, according to the valve gear 10 of the present embodiment, excellent responsiveness and excellent energy characteristics are realized without a disadvantage in workability in assembling or a disadvantage in reliability. be able to.

By the way, the magnetic flux flowing through the inside of the first core 34 advances in the axial direction of the first core 34 on the inner peripheral side and the outer peripheral side thereof. Then, in the process of moving from the inner peripheral side to the outer peripheral side in the upper part of the annular groove 34a, or in the process of moving from the outer peripheral side to the inner peripheral side, the first core 34 advances in the radial direction. The traveling direction of the magnetic flux is substantially the same as that of the first core 34 for the magnetic flux flowing inside the second core 38.

The traveling direction of the magnetic flux described above coincides with the extending direction of the first slits 34d, 38d and the second slits 34e, 38e at any part. Therefore,
The magnetic flux flowing through the insides of the first core 34 and the second core 38 is generated by the first slits 34d and 38d and the second slit 3.
The desired distribution route can be proceeded without intersecting with 4e and 38e. Therefore, the first slits 34d, 3
By providing 8d and the second slits 34e and 38e, the magnetic resistance of the first core 34 and the second core 38 is not increased.

Further, in this embodiment, the first slit 3
The 4d, 38d and the second slits 34e, 38e are provided so that the individual slits (including the grooves 34c, 38c) are symmetrically arranged around the through holes 34b, 38b at every 45 °. When slits are provided for the first core 34 and the second core 38, there is a slight difference between the electromagnetic force generated near the portion where the slit is provided and the electromagnetic force generated near the portion where the slit is not provided. Occurs. Therefore, the plurality of slits are formed in the through holes 34b and 38b.
When provided in an asymmetrical arrangement around the first core 3,
4 and the plunger 30, and between the second core 38 and the plunger 30, electromagnetic forces having non-uniform strength act.

If an electromagnetic force of non-uniform strength acts on the plunger 30 and the plunger 30 is driven by the electromagnetic force, the force between the valve shaft 14 and the valve guide 16 will be reduced.
Also, the first bearing 40 and the second bearing 42
A sliding friction, which is not preferable for ensuring a smooth sliding state, occurs between and the plunger guide 18.

In this embodiment, the plurality of slits provided for the first core 34 and the second core 38 are symmetrically arranged around the through holes 34b, 38b as described above. When the plurality of slits are provided symmetrically with respect to the first core 34 and the second core 38, the electromagnetic force acting on the plunger 30 becomes uniform over the entire circumference. Therefore, according to the valve operating system 10 of the present embodiment, it is possible to obtain an effect that the sliding portion is not unduly subjected to sliding friction during the operation of the valve operating system 10.

In the above-described embodiment, the first electromagnetic coil 32 and the second electromagnetic coil 36 are in the above-mentioned "electromagnetic coil", and the first core 34 and the second core 38 are in the above-mentioned "core", respectively. It is equivalent.

[0054]

As described above, according to the present invention, while providing high rigidity to the core, a long flow path for the eddy current flowing back in the core is secured in all the axial portions of the core. be able to. Therefore, according to the valve operating system for the internal combustion engine of the present invention, while sufficiently ensuring the rigidity of the core,
It is possible to realize a characteristic that is advantageous for quickly eliminating the eddy current.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a valve train for an internal combustion engine that is an embodiment of the present invention.

FIG. 2 is a front view of a first core included in the valve gear according to the present embodiment.

FIG. 3 is a plan view showing a first core included in the valve gear according to the present embodiment, as viewed in the direction of arrow III in FIG.

FIG. 4 is a cross-sectional view obtained when the first core included in the valve gear according to the present embodiment is cut along the line IV-IV shown in FIG.

FIG. 5 is a bottom view of the first core included in the valve gear according to the present embodiment, which is shown in the direction of arrow V in FIG.

FIG. 6 is a diagram showing directions of eddy currents generated in a specific condition in an annular conductor having uniform magnetism over the entire circumference.

FIG. 7 is a diagram showing directions of eddy currents generated in a specific situation in an annular conductor having a plurality of slits extending in a radial direction.

[Explanation of symbols]

 10 valve operating device 12 valve body 30 plunger 32 first electromagnetic coil 34 first core 34c (38c) groove 34d (38d) first slit 34e (38e) second slit 36 second electromagnetic coil 38 second core

Claims (1)

[Claims] 1. A valve operating system for an internal combustion engine, comprising: a core that holds an electromagnetic coil; and a plunger that is attracted to the core side when an exciting current is supplied to the electromagnetic coil. While having a first slit and a second slit extending from both axial end faces toward the other end face, the first slit and the second slit, without penetrating the core in the axial direction, and A valve train for an internal combustion engine, wherein the valve trains are provided so as to overlap each other.