JPH1037726A - Valve system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate manufacture of an inner yoke and an outer yoke by relatively sliding the inner and outer yokes of a pair of electromagnets along the axial direction of the stem of an engine valve, and fitting them to mutually, in a device provided with a pair of electromagnets on an armature. SOLUTION: A device is provided with a valve opening side electromagnet 13 for opening an engine valve V by sucking an armature, and a valve closing side electromagnet 14 for closing the engine valve V. The valve opening side electromagnet 13 is formed in such a constitution that a coil assembly 35 is arranged between an inner yoke 31 formed in a cylindrical shape and an outer yoke 32 formed in a cylindrical shape for enclosing the inner yoke 31, and the engaging part 31a of the lower end of the inner yoke 31 is fixed by engaging with the lower surface of the inward flange part 32a of the outer yoke 32. The valve closing side electromagnet 14 is also constituted in the same way. It is thus possible to facilitate manufacture of the inner yokes 31, 41 and the outer yokes 32, 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve train for an internal combustion engine, and more particularly to an armature that is linked to and connected to a stem of an engine valve, and an electromagnetic force for opening and closing the engine valve. The valve-opening and valve-closing side electromagnets exerting on the armature and the resilient force for urging the engine valve in the valve-opening and valve-closing directions, respectively, and the armature is held at a predetermined neutral position when the two electromagnets are deenergized. The present invention relates to a valve train for an internal combustion engine including a pair of resilient means.

[0002]

2. Description of the Related Art Conventionally, such a valve operating device is, for example, a PC.
It is already known from T International Publication WO95 / 00959 and the like.

[0003]

In the above publication, the inner and outer yokes of the valve-opening and valve-closing electromagnets are integrally formed in a double cylindrical shape with one end closed. Therefore, it is relatively difficult to manufacture the inner yoke and the outer yoke.

The present invention has been made in view of such circumstances, and has as its object to provide a valve train for an internal combustion engine in which an inner yoke and an outer yoke can be manufactured relatively easily.

[0005]

According to the first aspect of the present invention, the inner yoke and the outer yoke of the two electromagnets perform relative sliding along the axial direction of the stem of the engine valve. As possible, the inner yoke and the outer yoke can be easily manufactured as compared with the case where the inner yoke and the outer yoke are integrally formed.

According to the second aspect of the present invention, in the valve-closing electromagnet disposed opposite to the upper surface of the armature, one of the inner yoke and the outer yoke is fixed to the fixed support means as a fixed side, and The other of the yoke and the outer yoke is supported by the fixed-side yoke as a movable side that can be pushed up by contacting the armature before the engine valve is seated when the engine valve is closed. Prior to seating, the movable part of the inner yoke and the outer yoke and the armature are integrally moved to increase the inertial weight of the moving part that moves to the engine valve closing side by the electromagnetic force of the valve closing electromagnet, As a result, the valve closing operation speed before the engine valve is seated can be reduced to reduce the seating impact.

According to the third aspect of the present invention, the inner yoke and the outer yoke of the valve-closing electromagnet are brought into contact with each other after the armature comes into contact with the movable side of the two yokes during the closing operation of the engine valve. It is configured to increase the area. As a result, the magnetic flux generated between the two yokes after the armature comes into contact with the movable yoke is increased to increase the electromagnetic force of the valve-closing electromagnet. Can be reduced and the holding current can be reduced in the seated state of the engine valve.

According to the fourth aspect of the present invention, the inner yoke and the outer yoke of the valve-closing electromagnet are always in contact with the fixed side, and are in contact with the movable side of both yokes in accordance with the valve-closing seat of the engine valve. By providing the auxiliary magnetic circuit member, the magnetic flux between the inner yoke and the outer yoke is increased when the engine valve is seated, and the holding current in the seated state can be reduced.

According to the fifth aspect of the present invention, the power supply to the valve-closing electromagnet is reduced after a predetermined time has elapsed after the engine valve has been seated, so that the stable state after the engine valve is securely seated. Thus, the holding current can be reduced and the power consumption can be reduced.

Further, according to the invention, the upper end on the movable side of the inner yoke and the outer yoke of the valve-closing electromagnet is disposed facing the fluid chamber filled with fluid, and the fluid chamber is constricted. By being opened through
By giving the damper function to the valve train, it is possible to obtain a more excellent buffering effect when the engine valve is closed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a valve operating device in a neutral state of an engine valve. FIG. FIG. 3 is a diagram showing an attraction force characteristic according to an air gap between an electromagnet and an armature, FIG. 4 is a diagram showing an attraction force characteristic according to a valve lift of an engine valve, and FIG. FIG. 6 is a diagram showing a change in the moving part mass according to the valve lift of the engine valve, and FIG. 6 is a diagram showing a valve speed change according to the valve lift of the engine valve.

First, in FIG. 1, an engine valve V, which is an intake valve or an exhaust valve, is seated on a valve seat member 6 provided on a cylinder head 5 to close a valve port 6a. A stem 8 integrally connected to the body 7, and the stem 8 is slidably fitted in the guide cylinder 9. The guide cylinder 9 is provided with a flange portion 9 a at the upper end extending outward in a radial direction. The guide cylinder 9 is pressed into the cylinder head 5 until the flange portion 9 a is engaged with the upper surface of the cylinder head 5. Fixed.

The cylinder head 5 is provided with a valve train 10 according to the present invention. The valve train 10 is connected to the upper end of the stem 8 of the engine valve V.

The valve gear 10 includes a casing 11 connected to the cylinder head 5, an armature 12 movably housed in the casing 11 and linked to and connected to the stem 8 of the engine valve V. The casing 11 is positioned at a position facing the lower surface of the armature 12 so as to exert an electromagnetic force for attracting the armature 12 and opening the engine valve V.
A valve-opening electromagnet 13 is disposed in the casing 11 at a position facing the upper surface of the armature 12 so as to exert an electromagnetic force for attracting the armature 12 and closing the engine valve V. The valve-side electromagnet 14, the valve-opening-side coil spring 15 as a valve-opening-side resilient means for exerting a resilient force for biasing the engine valve V in the valve-opening direction, and biasing the engine valve V in the valve-closing direction. When the electromagnets 13, 14 on the valve-opening and valve-closing sides are deenergized, the valve-opening-side coil spring 1
And a valve-closing coil spring 16 as valve-closing spring means for holding the armature 12 at a predetermined neutral position in cooperation with the coil spring 5.

The casing 11 has a bottomed cylindrical upper case half 17 having a closed end at the upper end and a bottomed cylindrical lower case half 18 having a closed end at the lower end. The lower part of the casing 11, that is, the lower case half 18 is fastened to the upper surface of the cylinder head 5 by connecting means (not shown).

At the lower closed end of the lower case half 18, a recess 19 having a circular cross section facing the inner surface thereof and a through hole 20 opening at the center of the recess 19 are provided coaxially. The flange portion 9 a at the upper end of the guide cylinder 9 is inserted into the hole 20.
Are fitted. The upper portion of the stem 8 of the engine valve V penetrates through the guide cylinder 9 and protrudes into the casing 11. A retainer 22 is fixed to the upper end of the stem 8 by a split cotter 21. A cap-shaped receiving member 23 is fitted in the concave portion 19 so as to cover the flange portion 9a at the upper end of the guide cylinder 9, and surrounds the stem 8 that has penetrated the receiving member 23 movably in the axial direction. The valve-closing coil spring 16 is provided between the retainer 22 and the receiving member 23.
By the spring force of 6, the stem 8, ie, the engine valve V is elastically urged in the valve closing direction.

The armature 12 is formed in a disk shape. The upper end of the stem 8 is screwed into a bottomed cylindrical cap 24 that penetrates the center of the armature 12 and engages with the lower surface of the armature 12. Alternatively, a ring 25 slidably fitted and engaged with the upper surface side of the armature 12 is fitted and fixed to the cap 24 by press fitting or the like. As a result, the center of the armature 12 is screwed or slidably fitted to the upper end of the stem 8, and the ring 25 fixed to the cap 24.
It is pinched by.

At the upper closed end of the upper case half 17, a circular recess 26 having a circular cross section facing the inner surface thereof and a screw hole 27 opening at the center of the concave 26 are provided coaxially. A cylindrical adjusting member 28 whose end protrudes into the casing 11 is screwed into the screw hole 27, and the upper case half 17
A lock nut 29 that engages with the upper end of the upper case half 17 is screwed into the protrusion of the adjustment member 28 from the upper end of the upper case.
Therefore, by adjusting the advance / retreat position of the stopper 29, the adjustment member 28 can be firmly fixed to the casing 11 so that the advance / retreat position can be adjusted.

The valve-opening coil spring 15 is provided between the adjusting member 28 and the ring 25.
Due to the spring force of 5, the armature 12 is elastically urged downward, that is, in the direction in which the engine valve V opens. In addition, the spring force of the valve-opening-side coil spring 15 can be adjusted by adjusting the advance / retreat position of the adjusting member 28.
5, the spring force of the valve-closing coil spring 16 can be adjusted.

The valve-opening electromagnet 13 is fixedly disposed at a lower portion in the casing 11 so as to face the lower surface of the armature 12, and a coil 34 is wound around a bobbin 33 made of synthetic resin. The ring-shaped coil assembly 35 is disposed between the inner yoke 31 and the outer yoke 32.

The inner yoke 31 is formed in a cylindrical shape coaxially surrounding the stem 8 and the valve-closing-side coil spring 16. Further, the outer yoke 32 is formed in a cylindrical shape coaxially surrounding the inner yoke 31, and an inward flange 32 a protruding radially inward is integrally provided at a lower end portion of the outer yoke 32. The inner yoke 31 is slidably fitted to the inner periphery of the inward flange 32a. Moreover, at the lower end of the inner yoke 31, there is provided an engaging portion 31 a that protrudes outward in the radial direction, and the engaging portion 31 a is connected to the inward flange portion 3 of the outer yoke 32.
2a.

The coil assembly 35 includes the inner yoke 31
And inserted between the outer yoke 32 and
A pair of terminals (not shown) connected to the coil 34 is connected to a lead wire (not shown) on the inward flange 32 a side of the outer yoke 32. Therefore, the coil assembly 35 is substantially fixed to the outer yoke 32 side.

A recess 19 provided at the lower closed end of the lower case half 18 has a receiving member 2 fitted into the recess 19.
The holding cylinder 36 is fitted so that the holding cylinder 3 is sandwiched between the holding case 3 and the lower case half 18, and the upper end of the holding cylinder 36 is engaged with the lower closed end of the lower case half 18 around the recess 19. A mating flange portion 36a is provided integrally. Thus, the lower end of the inner yoke 31 of the valve-opening electromagnet 13 is in contact with and supported by the flange portion 36 a of the holding cylinder 36.

The valve-closing electromagnet 14 is disposed in the upper portion of the casing 11 so as to face the upper surface of the armature 12, and is formed by winding a coil 39 around a bobbin 38 made of synthetic resin. Coil assembly 40
Are arranged between the inner yoke 41 and the outer yoke 42.

The inner yoke 41 is formed in a cylindrical shape surrounding the valve-opening-side coil spring 15 coaxially. Further, the outer yoke 42 is formed in a cylindrical shape coaxially surrounding the inner yoke 41, and has an inward flange portion 42a protruding radially inward at an upper end portion of the outer yoke 42.
Are provided integrally, and the inner yoke 41 is slidably fitted to the inner periphery of the inward flange portion 42a. In addition, an engaging portion 41a that protrudes radially outward is provided at the upper end of the inner yoke 31, and the engaging portion 41a can be engaged with the upper surface of the inward flange portion 42a of the outer yoke 42.

The coil assembly 40 includes an inner yoke 41
And inserted between the outer yoke 42 and
A pair of terminals (not shown) connected to the coil 39 is connected to a lead wire (not shown) on the inward flange portion 42 a side of the outer yoke 42. Therefore, the coil assembly 39 is substantially fixed to the outer yoke 42 side.

The upper end of the outer yoke 42 is in contact with and supported by the upper closed end of the upper case half 17, and the lower end of the outer yoke 42 and the upper end of the outer yoke 32 of the valve-opening electromagnet 13 Between them, a sleeve 43 coaxially surrounding the armature 12 is interposed. Therefore, the valve-opening electromagnet 13 and the valve-closing electromagnet 14
Is the outer yoke 4 of the valve-closing electromagnet 14 when the casing 11 is formed by connecting the upper and lower case halves 17 and 18 to each other.
2. The sleeve 43, the outer yoke 32 of the valve-opening electromagnet 13, the engaging portion 31a of the inner yoke 31, and the holding cylinder 36 are fixed between the upper and lower case halves 17 and 18 so as to be fixedly supported. It will be in the state fixed in the casing 11 as a means.

Further, the engaging portion 41a at the upper end of the inner yoke 41 is housed in the concave portion 26 at the upper closed end of the upper case half 17, and is separated from the inward flange portion 42a at the upper end of the outer yoke 42 to be upward. It is possible to move to.

In such a valve-closing electromagnet 14, the length of the inner yoke 41 is, as shown in FIG.
It is set to be in a position where the lower end of the inner yoke 41 is projected downward by a distance L ₁ from the lower end of the outer yoke 42 in a state 1a and the engaged inward flange portion 42a of the outer yoke 42 The lower end of the inner yoke 41 at this time is set such that the armature 12 contacts the lower end of the inner yoke 12 before the engine valve V is seated on the valve seat member 6 when the engine valve V is closed. .

Next, the operation of the first embodiment will be described. In the valve-opening-side and valve-closing-side electromagnets 13 and 14 of the valve train 10, the inner yokes 31, 41 and the outer yokes 32, 42 have the engine valve V The stems 8 are fitted with each other so as to enable relative sliding along the axial direction. For this reason, the inner yokes 31 and 41 and the outer yokes 32 have relatively simple shapes as compared with a conventional one in which the inner yoke and the outer yoke are integrally formed in a double cylindrical shape with one end closed. , 4
2 can be formed individually and fitted to each other, so that the manufacture of the inner yokes 31, 41 and the outer yokes 32, 42 becomes relatively easy.

In the valve-closing electromagnet 14, the inner yoke 41 is supported by an outer yoke 42 fixed to the casing 11, which is a fixed supporting means, so as to be capable of vertical sliding relative to each other. Before the engine valve V is seated on the valve seat member 6 during the valve closing operation of the
The length of the inner yoke 41 is set so that the armature 12 contacts the lower end of the inner yoke 41. Therefore, when the engine valve V is closed as shown in FIG. 2, the inner yoke 41 is pushed up by the armature 12, and
Be slid so as to be positioned above the inward flange portion 42a of the distance L ₁ or less is the distance _{L 2 (L 2 ≦ L 1} ) by the engaging portion 41a is the outer yoke 42 at the upper end of the inner yoke 41 become.

As described above, when the engine valve V is closed, the inner yoke 41 is pushed up by contacting the armature 12 before the engine valve V is seated, thereby closing the engine valve V immediately before the valve seats. The speed can be reduced, and the impact at the time of sitting can be reduced. That is, when the air gap between the armature 12 and the valve-closing electromagnet 14 becomes small during the closing operation of the engine valve V, as shown in FIG.
As the engine valve V approaches the fully closed position, as shown in FIG.
4, the armature 12 contacts the inner yoke 41 at the crank angle θ ₀ at which the engine valve V approaches the fully closed position, as shown in FIG. As a result, the mass of the moving part increases dramatically. Therefore, the valve closing operation speed of the engine valve V after the crank angle θ ₀ is reduced as shown by the solid line in FIG. 6, and the valve body 7 of the engine valve V is gradually moved to the valve seat member 6. It becomes possible to reduce the impact at the time of sitting and sitting.

On the other hand, in the conventional motor in which the inner yoke and the outer yoke are both fixed, as shown by the broken line in FIG. As a result, impact noise and starting were unavoidable, leading to a decrease in durability.

By the way, in order to reduce the impact when the engine valve V is closed and seated, it is proposed to use a damper using hydraulic pressure or pneumatic pressure or to control the timing of energizing the valve-closing electromagnet 14. However, in the case of using the damper, it is necessary to set the electromagnetic force to be exerted by the valve-closing electromagnet 14 by the amount corresponding to the reaction force of the damper, which leads to an increase in power consumption. Further, the hydraulic pressure and the air pressure are easily influenced by the ambient temperature and the use environment temperature, and it is difficult to perform a stable shock relaxation control. In addition, the control of the energization timing is stable because the attraction force changes according to the air gap between the valve closing electromagnet and the armature, but only the energization timing is controlled irrespective of the armature, that is, the position of the engine valve. Valve behavior cannot be obtained.

In contrast to those using such a damper or controlling the energization timing, the present invention provides a method for closing the engine valve V even when the energization current to the valve-closing electromagnet 14 is controlled to be constant. The valve closing operation speed can be reduced by moving the armature 12 and the inner yoke 41 integrally before seating, so that power consumption can be reduced and a stable valve closing behavior can be obtained.

FIGS. 7 and 8 show a second embodiment of the present invention. FIG. 7 shows a partial configuration of the valve-closing-side electromagnet. FIG. 7A shows a longitudinal section before the inner yoke is pushed up. FIG. 8B is a longitudinal sectional view after the inner yoke is pushed up, and FIG. 8 is a simplified block diagram showing the configuration of the control device.

In the valve-closing electromagnet, the inner yoke 4
An annular concave portion 44 is provided on the outer periphery of the upper end of the inner yoke 41 adjacent to the engaging portion 41a at the upper end of the inner yoke 41.
The width W of the annular concave portion 44 along the axial direction of the inner yoke 41
₁ is an inward flange 4 at the upper end of the outer yoke 42.
It is set smaller than 2a of thickness W _2.

The contact width W ₃ between the inner yoke 41 and the outer yoke 42 is shown in FIG. 7A before the inner yoke 41 is pushed up by the armature 12 (see FIGS. 1 and 2). When the inner yoke 41 is pushed up while being (W ₂ −W ₁ ) as described above, the facing contact width W ₃ increases as shown in FIG. It becomes gradually bigger according to. That is, when the inner yoke 41 starts being pushed up during the valve closing operation, the contact area between the inner yoke 41 and the outer yoke 42, that is, the magnetic flux increases.

In FIG. 8, the energization of the valve-opening electromagnet 13 and the valve-closing electromagnet 14 is controlled by crank angle detecting means 45.
Is controlled by the control means 46 in response to a signal from the crank angle detecting means 45.
After a predetermined time has passed since the signal from the engine has become the crank angle corresponding to the time when the engine valve is seated, the amount of electricity to the valve-closing electromagnet is reduced.

According to the second embodiment, when the inner yoke 41 starts to be pushed up by the armature 12 when the valve is closed, the magnetic flux between the inner yoke 41 and the outer yoke 42 increases, and the electromagnetic force of the valve-closing electromagnet increases. Will do. However, the armature 1 of the inner yoke 41
(2) The inertia weight is increased by the integral operation of the engine valve (2), and the suction force is increased by increasing the magnetic flux in the seated state of the engine valve while suppressing the valve closing operation speed increase before seating due to the increase in the electromagnetic force. Thus, the valve-closing holding current of the valve-closing electromagnet can be reduced.

Furthermore, the control means 46 reduces the amount of electricity supplied to the valve-closing electromagnet after a predetermined time has passed after the valve-closure seating, so that the holding current can be reduced in a stable state after the seat is securely seated, thereby reducing power consumption. The amount can be reduced.

FIGS. 9 to 11 show the first embodiment of the second embodiment.
9 shows a third modification example. In the first modification example shown in FIG. 9, the outer periphery of the upper end of the inner yoke 41 may be opposed to the inner periphery of the inward flange 42 a at the upper end of the outer yoke 42 with a space therebetween. A small diameter portion 47 is provided adjacent to the engaging portion 41a, and a tapered portion 48 connected to the small diameter portion 41a is provided so as to have a larger diameter as it goes downward.

In the second modification shown in FIG. 10, an annular concave portion 44 adjacent to the engaging portion 41a at the upper end of the inner yoke 41 is provided on the outer periphery of the upper end of the inner yoke 41.
A large-diameter portion 49 is provided above the inward flange portion 42a at the upper end of the outer yoke 42 so as to face the outer surface of the inner yoke 41 at intervals.

In the third modification shown in FIG. 11, a small-diameter portion 47 and a tapered portion 48 are provided on the outer periphery of the upper end of the inner yoke 41, and the upper end of the outer yoke 42 is located above the inward flange 42a. A tapered portion 50 having a large diameter is provided.

Also in each of the modifications shown in FIGS. 9 to 11, when the inner yoke 41 starts to be pushed up by the armature 12 at the time of closing the valve, the magnetic flux between the inner yoke 41 and the outer yoke 42 is increased to close the valve. By increasing the electromagnetic force of the valve-side electromagnet, the same effect as in the second embodiment can be obtained.

FIGS. 12 to 14 show a third embodiment of the present invention. FIG. 12 is a longitudinal sectional view showing the vicinity of the valve-closing side electromagnet before the inner yoke is pushed up, and FIG. Vertical sectional view of the vicinity of the valve-closing electromagnet after lifting, FIG.
FIG. 4 is a diagram showing a suction force characteristic according to a valve lift of the engine valve.

An upper closed end of the upper case half 17 is provided with a concave portion 26 'having a circular cross section facing the inner surface thereof, and a dish-shaped auxiliary magnetic circuit having a hole 51 through which the adjusting member 28 penetrates in the center. The member 52 is fitted in the recess 26 '.
The auxiliary magnetic circuit member 52 is formed so as to always contact the outer yoke 42 and to contact the upper end of the inner yoke 41 moved upward as shown in FIG. . The inner yoke 41 is pushed up on the outer periphery of the upper end of the inner yoke 41 when the valve is closed.
In order to increase the contact area between the first and outer yokes 42, a tapered portion 53 having a larger diameter as it goes upward is provided adjacent to the engaging portion 41a.

According to the third embodiment, the magnetic flux between the inner yoke 41 and the outer yoke 42 is further increased by the auxiliary magnetic circuit member 52 after the valve is closed and seated, and the attraction force of the valve-closing electromagnet is represented by the solid line in FIG. As shown, it can increase dramatically. Therefore, it is possible to further reduce the valve closing holding current as compared with the conventional one shown by the broken line in FIG.

FIG. 15 shows a fourth embodiment of the present invention, in which parts corresponding to the above embodiments are given the same reference numerals.

A cylindrical body 54 coaxially surrounding the adjusting member 28 is press-fitted into the upper closed end of the upper case half 17 so as to define the inner peripheral surface of the concave portion 26 facing the inner surface. The upper end of the inner yoke 41 of the side electromagnet 14, that is, the engaging portion 41a, is slidably fitted in the concave portion 26 such that the inner periphery thereof is in sliding contact with the outer surface of the cylindrical body 54. Thereby, the upper case half 17 and the cylindrical body 5
An annular fluid chamber 55 is formed by 4 and the engaging portion 41a. The upper case half 17 is connected to a connection joint 56 having a built-in check valve for connecting a hydraulic pressure source or an air pressure source to the fluid chamber 55.
Is filled with a fluid such as oil or air. Moreover, the engaging portion 4
1a and between the outer surface of the cylindrical body 54 and the recess 2
The fluid chamber 5 is provided between the inner surface of
There is formed a minute gap that functions as apertures 57 and 58 for opening the casing 5 into the casing 11.

According to the fourth embodiment, the upper end of the inner yoke 41 can be made to face the fluid chamber 55 with a simple structure in which the cylindrical body 54 is simply pressed into the upper case half 17, and the inner yoke 41 The fluid in the fluid chamber 55 is throttled by the throttles 57 and 58 and released to the outside in accordance with the rise of the pressure, so that a damper function can be exhibited, and a more excellent buffering effect can be obtained when the valve is closed.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, in the valve-closing electromagnet, the inner yoke may be fixed and the outer yoke may be movable.

[0055]

As described above, according to the first aspect of the invention, the inner yokes and the outer yokes of the valve-opening and valve-closing-side electromagnets are slidably fitted to each other, whereby both yokes are engaged. The inner yoke and the outer yoke can be manufactured more easily as compared with the case where is integrally formed.

According to the second aspect of the present invention, one of the inner yoke and the outer yoke of the valve-closing electromagnet is set to the fixed side, and the other is set to the position before the engine valve is seated when the engine valve is closed. By making the movable side that can be pushed up by contacting the armature, the movable side yoke and armature are moved together before the engine valve is seated, so that the electromagnetic valve of the valve-closing electromagnet moves The inertia weight of the moving part that moves to the valve closing side is increased, and the valve closing operation speed before the engine valve is seated is moderated to reduce the seating impact.

According to the third aspect of the present invention, the two yokes of the valve-closing electromagnet are configured to increase the contact area of the yokes after the armature comes into contact with the movable yoke during the valve closing operation. Therefore, the magnetic flux generated between the two yokes after the armature contacts the movable yoke is increased to increase the electromagnetic force of the valve-closing electromagnet, and the inertia weight of the moving part increases the valve closing operation speed before seating. It is possible to reduce the holding current in the seated state of the engine valve while avoiding the increase.

According to the fourth aspect of the present invention, the movable yoke is brought into contact with the auxiliary magnetic circuit member which is always in contact with the fixed yoke of the valve closing electromagnet in accordance with the valve closing seat of the engine valve. As a result, the magnetic flux between the two yokes in the seated state of the engine valve can be increased, and the holding current in the seated state can be reduced.

According to the fifth aspect of the present invention, the power supply to the valve-closing electromagnet is reduced after a lapse of a predetermined time after the engine valve is seated, so that the stable state after the engine valve is securely seated. Thus, the holding current can be reduced and the power consumption can be reduced.

According to the sixth aspect of the present invention, the fluid chamber facing the upper end of the movable side yoke of the valve-closing electromagnet is opened through a throttle, so that the valve operating device has a damper function. An excellent buffering effect can be obtained when the engine valve is closed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a valve operating device in a neutral state of an engine valve according to a first embodiment.

FIG. 2 is a vertical cross-sectional view of the valve operating device in a state in which the engine valve is closed and seated.

FIG. 3 is a diagram illustrating an attractive force characteristic according to an air gap between an electromagnet and an armature.

FIG. 4 is a diagram showing a suction force characteristic according to a valve lift of an engine valve.

FIG. 5 is a diagram showing a change in mass of a moving part according to a valve lift of an engine valve.

FIG. 6 is a diagram showing a valve speed change according to a valve lift of an engine valve.

7A and 7B show a partial configuration of a valve-closing-side electromagnet according to a second embodiment, in which FIG. 7A is a longitudinal sectional view before pushing up an inner yoke, and FIG. 7B is a longitudinal sectional view after pushing up an inner yoke. is there.

FIG. 8 is a simplified block diagram showing a configuration of a control device.

FIG. 9 is a cross-sectional view corresponding to FIG. 7, showing a first modification of the second embodiment.

FIG. 10 is a sectional view corresponding to FIG. 7, showing a second modification of the second embodiment.

FIG. 11 is a sectional view corresponding to FIG. 7, showing a third modification of the second embodiment;

FIG. 12 is a longitudinal sectional view of the vicinity of a valve-closing-side electromagnet in a state before pushing up an inner yoke according to a third embodiment.

FIG. 13 is a longitudinal sectional view showing the vicinity of the valve-closing-side electromagnet after pushing up the inner yoke.

FIG. 14 is a diagram showing a suction force characteristic according to a valve lift of an engine valve.

FIG. 15 is a sectional view corresponding to FIG. 12 of the fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 8 ... Stem 11 ... Casing as support means 12 ... Armature 13 ... Electromagnet on valve-opening side 14 ... Electromagnet on valve-closing side 15 ... Valve-opening side as valve-opening resilient means Coil spring 16: Valve-closing-side coil spring as valve-closing-side resilient means 31, 41: Inner yokes 32, 42: Outer yokes 34, 49: Coil 46: Control main end 52 ... Auxiliary magnetic circuit member 55 ... Fluid chamber 57,58 ... Throttle V ... Engine valve

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshio Yokoyama 1-4-1, Chuo, Wako-shi, Saitama

Claims (6)

[Claims] An armature (12) interlocked with and connected to a stem (8) of an engine valve (V), and coils (34, 3).
9) is arranged and disposed between the inner yoke (31, 41) and the outer yoke (32, 42), and applies the electromagnetic force toward the opening and closing directions of the engine valve (V) to the armature (12). ) And the electromagnets (13, 14) acting on the valve-opening side and the valve-closing side, respectively, and the resilient force for urging the engine valve (V) in the valve-opening and valve-closing directions, respectively. In the valve train for an internal combustion engine, comprising a pair of resilient means (15, 16) for holding the armature (12) at a predetermined neutral position when the power is deenergized in (14), the inner yoke of both electromagnets (13, 14) is provided. (31, 41) and outer yoke (32, 42)
Are fitted to each other to enable relative sliding along the axial direction of the stem (8) of the engine valve (V). 2. An electromagnet (14) disposed on a valve-closing side facing the upper surface of an armature (12), wherein one of an inner yoke (41) and an outer yoke (42) is fixed to a fixed support means (11). ), And the other of the inner yoke (41) and the outer yoke (42) comes into contact with the armature (12) before the engine valve (V) is seated when the engine valve (V) is closed, and is pushed up. 2. The valve train for an internal combustion engine according to claim 1, wherein the movable side is supported by the fixed side yoke. 3. The inner yoke (41) and the outer yoke (42) of the valve-closing electromagnet (14), and the armature (12) is connected to the two yokes (41, 42) when the engine valve (V) is closed. 3. The valve train for an internal combustion engine according to claim 2, wherein the contact area of the yokes is increased after the contact with the movable side. 4. A fixed side of the inner yoke (41) and the outer yoke (42) of the valve closing electromagnet (14) is always in contact with the fixed side, and both yokes ( 4. The valve train for an internal combustion engine according to claim 2, further comprising an auxiliary magnetic circuit member (52) that comes into contact with a movable side of the movable side (41, 42). 5. A control means for controlling the energization of both electromagnets (13, 14) so as to reduce the amount of energization to the valve-closing electromagnet (14) after a predetermined time has elapsed after the engine valve (V) is seated. The valve train for an internal combustion engine according to claim 3 or 4, further comprising (46). 6. The movable yoke upper end of the inner yoke (41) and the outer yoke (42) of the valve-closing electromagnet (14) is disposed facing a fluid chamber (55) filled with fluid. 6. The valve train for an internal combustion engine according to claim 2, wherein the fluid chamber (55) is opened via a throttle (57, 58).