JPH10103032A - Solenoid valve system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid valve system which stably seals off a combustion chamber against gas for a longer period while its valve opens and simplifies the control for its electromagnetic force generator means. SOLUTION: A displacement-absorbing means for absorbing the displacement of a valve element 10 at the close contact with a valve seat is interposed between a movable body 6 adapted to be attracted to an electromagnetic force generator means 30 or 32 by a constant moving distance and the valve element 10 adapted to move according to the movement of the movable body 6 being attracted. That arrangement simplifies the control for the electromagnetic force generator means 30 and 32 as well as reliably brings the valve element 10 into close contact with the valve seat without being affected by the displacement of the valve element 10 being closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic valve train, and more particularly to an electromagnetic valve train used for controlling intake and exhaust of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an electromagnetic valve mechanism in which a drive system of an intake / exhaust valve of an internal combustion engine is changed from a system driven by a cam to a system driven electrically by a solenoid valve using electromagnetic force. ing. By using this electromagnetic valve mechanism, the opening and closing timing of the valve can be arbitrarily set according to the operating state of the internal combustion engine, and the engine output characteristics can be easily changed and the fuel efficiency can be easily improved.

FIG. 3 is a schematic explanatory view of a conventional electromagnetic valve mechanism. As shown in the figure, the valve train 102 includes a valve portion 102a and a valve stem portion 102b, and is provided on a cylinder head portion 104 via a stem guide 106 so as to be able to reciprocate.

The valve portion 102a is provided on a valve seat 1 provided at a periphery of an opening of the intake / exhaust port 108 to the combustion chamber 110.
12 is formed in a shape that can be in close contact with the same. An armature 114 made of a magnetic material is fixed to the distal end portion 102c of the valve stem portion 102b. When a predetermined current is supplied in the reciprocating direction, an electromagnetic force is generated to attract the armature 114. A valve opening electromagnetic coil 116 and a valve closing electromagnetic coil 118 are provided.

A valve-closing spring 1 that always urges the valve 102 in the valve-closing direction (upward in the figure) inside the valve-opening electromagnetic coil 116 and on the outer periphery of the valve stem 102b.
A valve-opening spring 12 for biasing the valve 102 in the valve-opening direction (downward in the figure) is provided inside the valve-closing coil 118 on the opposite side of the armature 114.
2 are provided.

The valve-closing spring 120 and the valve-opening spring 122 maintain the armature 114 at an intermediate position between the valve-opening electromagnetic coil 116 and the valve-closing electromagnetic coil 118 when no power is supplied, and have a small attractive force when power is supplied. A biasing force is set so that suction can be performed with. That is, when the valve closing electromagnetic coil 118 is energized, the armature 1
14 is attracted to the valve closing electromagnetic coil 118 side against the urging force of the valve opening spring 122 in the opening direction,
Moves in the valve closing direction (upward in the figure). When the valve portion 102a and the valve seat 112 come into close contact (hereinafter simply referred to as seating), the combustion chamber 110 and the intake / exhaust port 1
08, the gas is sealed and the valve is closed.

When the valve opening electromagnetic coil 116 is energized, the armature 114 is connected to the valve closing spring 12.
The valve valve 102 is attracted to the valve opening electromagnetic coil 116 against the urging force of 0, and the valve train 102 moves in the valve opening direction (downward in the figure).
The valve is opened.

[0008] As shown in the figure, the above-mentioned electromagnetic valve mechanism has an armature 1 when the valve 102 should be closed.
A gap L, which is a minute gap, is provided between the valve 14 and the valve closing coil 118. Due to the gap L, it is possible to ensure the close contact between the valve portion 102a and the valve seat 112 when the valve is closed, and the combustion chamber 110 and the intake / exhaust port 108
And a good gas sealing state can be formed.

That is, when the valve is closed, the armature 1
14 and the valve closing electromagnetic coil 118 and the valve section 102
a and the valve seat 112 both occur at the same time (hereinafter simply referred to as “double fit”), or the armature 114 and the valve closing coil 118 come into contact first, so that the valve portion 102 a and the valve Sheet 112
This prevents the occurrence of poor adhesion to the gas chamber, thereby preventing poor gas sealing in the combustion chamber.

FIG. 4 is a graph showing the relationship between the distance between the valve closing electromagnetic coil 118 and the armature 114 and the attraction force of the valve closing electromagnetic coil 118. As shown in the drawing, the attraction force for attracting the mover by the electromagnetic force of the electromagnetic coil shows a characteristic that it decreases rapidly as the distance between the electromagnetic coil and the armature increases (moves rightward in the figure). I have. Therefore, it is desirable that the gap L be smaller so that the suction force can be set large from the viewpoint of quick and reliable opening and closing operation of the valve.

[0011]

However, for example, thermal expansion due to a temperature change of the valve 102 or abrasion of the seating surfaces of the valve portion 102a and the valve seat 112 due to a change over time, or accumulation of carbon or the like due to the accumulation of carbon, etc.
Is changed, the gap L also increases / decreases.

If the gap L is set to a small value without considering such a change in the gap L, a gas seal failure due to double fitting or the like will occur, and a reduction in engine output due to compression failure in the compression stroke of the internal combustion engine will be caused. Becomes Therefore, conventionally, in order to prevent such a problem, the gap L is set to be large from the beginning to prevent double fitting and the like.

However, if the gap L is set to be large from the beginning, the attractive force of the coil is reduced by that amount, so that the coil must be changed to a large coil capable of generating a greater attractive force. Therefore, it is difficult to secure the mounting space due to the increase in the size of the device, and the cost is increased due to the increase in the current value of the valve driving device for driving the coil, the increase in the capacity, and the like.

Further, for example, an electromagnetic valve mechanism is disclosed in
No. 179806, that is, in the valve closing operation, the seating speed of the valve train is reduced by controlling the current value to the coil for valve closing just before the valve seat comes into close contact with the valve seat. Conventionally, seating speed control for reducing the impact when the valve train is seated on a valve seat is known.

However, since the attraction force of the electromagnetic coil changes due to the increase or decrease of the gap L, it is necessary to control the current value corresponding to the change of the gap L at the same amount of valve movement in the seating speed control. That is, as shown in FIG. 4 described above, when the gap L at the time of closing the valve is small, the attraction force is large, and when the gap L is large, the attraction force is small. , It is necessary to perform control for changing the current value to make the seating speed constant, which complicates the control algorithm.

The present invention has been made in view of the above-mentioned problems, and has as its object to stably perform gas sealing of a combustion chamber when a valve is closed for a long period of time and to simplify control of an electromagnetic force generating means. An object of the present invention is to provide an electromagnetic valve mechanism that can be realized.

[0017]

According to a first aspect of the present invention, there is provided an electromagnetic valve mechanism in which a moving distance of a mover is always kept constant, and a valve of the valve is interposed between the mover and the valve. Displacement absorbing means is provided for absorbing a change in position during close contact with the seat. Therefore, since the moving distance is always constant, the control of the electromagnetic force generating means can be simplified, and the close contact of the valve train with the valve seat by the suction movement of the mover can be reliably performed.

In the electromagnetic valve mechanism according to the second aspect, the mover comes into close contact with the electromagnetic force generating means when the valve is closed. Therefore,
Since the distance for sucking the mover can be shortened, the mover can be sucked with a small suction force. This makes it possible to further reduce the size of the electromagnetic force generating means.

In the electromagnetic valve mechanism according to the third or fourth aspect, the displacement absorbing means always applies a pressing force weaker than the urging force to the movable element to press the valve in the forward direction. And, when the close contact position of the valve and the valve seat at the time of valve closing is displaced in the forward direction, it is extended by the displacement, and when displaced in the reverse direction, it contracts by the displacement and always presses the valve. I do.

Therefore, similarly to the operation and effect of the first aspect, when the valve is closed, the valve can be securely brought into close contact with the valve seat.
Control of the electromagnetic force generating means can be simplified.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory sectional view of a main part of an electromagnetic valve mechanism according to the present invention.
As illustrated, in the present embodiment, the electromagnetic valve mechanism 1 generally includes an electromagnetic force generating unit 4, a movable element 6, a displacement absorbing unit 8,
And the valve element 10.

The valve body 10 has a valve portion 10a and a valve stem portion 10b, and is provided on the cylinder head portion 14 so as to be reciprocable via a stem guide 16. The valve portion 10a is provided in a combustion chamber 20 of an intake / exhaust port 18. It is formed in a shape that can be in close contact with the valve seat 22 provided on the periphery of the opening to the outside.

The top surface 10c of the valve stem 10b is
The cotter pin 24 is in surface contact with the distal end of the plunger 48 of the displacement absorbing section 8 described later, and the cotter pin 24 is inserted between the valve stem 10b and the spring receiver 26.
A valve closing spring 28 is provided between the spring receiver 26 and the cylinder head 14 as valve closing urging means for urging the valve body 10 in the valve closing direction (reverse direction).

The electromagnetic force generating section 4 includes a valve closing electromagnetic coil 30.
And a valve opening electromagnetic coil 32. The valve opening electromagnetic coil 32 is incorporated in a lower core 34 having a cylindrical shape and a U-shaped cross section, and is fixed to the cylinder head portion 14. The valve-closing electromagnetic coil 30 is incorporated in an upper core 38 having a substantially cylindrical shape having a lid on the upper surface and having a U-shaped cross section, and is fixed to the cylinder head 14 similarly to the lower core 34.

The mover 6 has a substantially disc-shaped suction section 4.
0 and a housing 42 for accommodating the substantially cylindrical displacement absorbing portion 8 having an upper portion closed at the center thereof and made of a magnetic material having a substantially convex cross-section. It is provided movably in the forward and reverse directions between the valve electromagnetic coil 30 and the valve opening electromagnetic coil 32. Accommodation section 42
An opening 38a formed in the lid of the upper core 38
It protrudes more upward and plays a role of a guide rod that maintains the posture of the mover 6 when the mover 6 moves.

A valve-opening spring 44 is provided between the accommodating portion 42 and the upper core 38 to constantly urge the mover 6 in the forward direction (downward in the figure) which is the valve-opening direction. The biasing force is set substantially the same as the valve closing spring. Therefore, at the time of non-energization, the movable element 6 is maintained at a substantially intermediate position between the two coils by the urging force of the valve closing spring 28 and the valve opening spring 44, and can be sucked with a small suction force at the time of energization. FIG. 1 shows a closed state in which a current is supplied to the valve closing electromagnetic coil 30 and the movable element 6 is attracted to the valve closing electromagnetic coil 30.

Next, the structure of the displacement absorbing section 8 as the displacement absorbing means will be described in detail below with reference to FIG.
In this embodiment, a hydraulic buffer mechanism is used as the displacement absorbing means. FIG. 2 is an enlarged explanatory view of a main part of a peripheral portion of the displacement absorbing section 8 in FIG. As shown in the drawing, the displacement absorbing section 8 is housed in the housing section 42 of the mover 6,
A plunger 48 is provided which comes into contact with and presses against the top surface 10c of the valve element 10.

The plunger 48 has a large-diameter portion 50 and a small-diameter portion 52 having a smaller diameter than the large-diameter portion 50 at an upper portion, and has a hollow interior. The small-diameter portion 52 has a small-diameter orifice 54 communicating the inside and the outside.
Is provided. Further, a tapered check ball housing surface 55 whose diameter gradually decreases downward is formed at an inner boundary between the large diameter portion 50 and the small diameter portion 52.

The large diameter portion 50 forms a high pressure chamber 56 with the accommodating portion 42. The high pressure chamber 56 is filled with oil, and further provided with a return spring 58 for urging the plunger 48 in the forward direction. I have. The urging force of the return spring 58 is set weaker than the urging force of the valve closing spring 28. A check ball retainer 60 is provided between the return spring 58 and the plunger 48, and the check ball 64 is received by the check ball spring 62 on the check ball receiving surface 54.

The small diameter portion 52 has a plunger 48 on its outer periphery.
Of the plunger 48 is guided by the guide member biasing spring 65 to guide the plunger 48 in the forward and reverse directions.
And a plunger guide member 68 that forms a hydraulic low-pressure chamber 66 therebetween.

The plunger guide member 68 has a substantially cylindrical shape, the inner diameter of which is slightly larger than the small diameter portion 52 of the plunger 48, and the outer diameter of which is slightly smaller than the inner diameter of the storage chamber 42. It is formed small. Two O 2 seals the oil filled in the low-pressure chamber 66 on the inner peripheral surface 70 and the outer peripheral surface 72 of the plunger guide member 68.
It has rings 74a and 74b.

The guide member biasing spring 65 is held at its lower end by a spring retainer 74, and the spring retainer 74 is fitted in a groove 76 provided near an opening on the inner peripheral surface of the housing 42. And is housed in the housing part 42.

Next, a description will be given of how the displacement absorbing portion 8 serving as the displacement absorbing means absorbs the displacement of the position change when the valve body 10 is in close contact with the valve seat 22. First, a valve drive unit (not shown) energizes the valve-closing electromagnetic coil 30 to generate a magnetic flux, and attracts and moves the mover 6 by an attractive force that is an electromagnetic force corresponding to the magnetic flux density.

Accordingly, the mover 6 is attracted and adhered to the valve closing electromagnetic coil 30 against the urging force of the valve opening spring 44, and the valve body 10 is turned in the opposite direction by the valve closing spring 28, that is, in the valve closing direction. , The movable member 6 moves in the opposite direction with the movement of the movable element 6, and the valve portion 1 of the valve body 10
0a is seated on the valve seat 22 and is in the valve closed state (the state of FIG. 1).

Here, for example, when the contact surface between the valve portion 10a and the valve seat 22 is worn, or when the engine shrinks when the engine is cold due to a temperature change of the valve body 10,
When the valve is closed, the top surface 10c is displaced toward the displacement absorbing portion 8 side.
Here, the top surface 10c pushes back the plunger 48 by the amount of displacement by the urging force of the valve closing spring 28, and the valve portion 10a is always in close contact with the valve seat 22 when the valve is closed.

That is, since the urging force of the return spring 58 in the forward direction is weaker than the urging force of the valve closing spring 28 in the reverse direction, the plunger 48 is pushed back in the reverse direction. Since the high-pressure chamber 56 is filled with oil, the oil is supplied to the outer periphery of the large-diameter portion 50 of the plunger 48 and the check ball 64 and the check ball housing surface 55.
, A small amount leaks to the low pressure chamber 66 side, and the plunger 48
Moves in the opposite direction by the amount of displacement, and when the valve is closed,
The displacement of the valve body 10 can be absorbed by pressing the c.

When the top surface 10c is displaced in a direction away from the displacement absorbing portion 8 when the valve is closed due to adhesion of deposits such as carbon on the seating surface and thermal expansion due to a temperature change of the valve body 10, the plunger 48 is displaced. Extends by the displacement. In other words, the force of pushing back the top surface 10c to the plunger 48 decreases due to this displacement, so that the plunger 48 moves in the forward direction by the urging force of the return spring 58. At this time, since the pressure in the high-pressure chamber 56 decreases, the oil in the low-pressure chamber 66 passes through the orifice 54 and passes through the check ball 64.
And flows into the high-pressure chamber 56.

Since the oil flows into the high-pressure chamber 56 at a speed determined by the relationship between the viscosity of the oil and the orifice 54, the plunger 48 moves at a speed at which the oil flows in the positive direction by the amount of the displacement, and always moves to the top when the valve is closed. The displacement of the valve body 10 with respect to the mover 6 can be absorbed by pressing the surface 10c.

Accordingly, the displacement absorbing portion 8 absorbs the change in position when the valve body 10 is seated, so that the valve-closing electromagnetic coil 36 attracts the movable element 6 and ensures the valve portion 10a.
Can be brought into close contact with the valve seat 22. Also,
The moving distance of the mover 6 due to a change over time or the like does not change and can always be kept constant. Therefore, the control algorithm of the valve closing electromagnetic coil 36 in the seating speed control of the valve body 10 is simplified without being complicated. can do.

[0040]

As described above, according to the electromagnetic valve mechanism of the present invention, it is possible to make the moving distance of the mover constant and absorb the position change when the valve is in close contact with the valve seat. Therefore, the control of the electromagnetic force generating means can be simplified, and the gas seal of the combustion chamber when the valve is closed can be stably performed over a long period of time.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a main part of an electromagnetic valve mechanism according to an embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a main part of FIG. 1;

FIG. 3 is a schematic explanatory view of a conventional electromagnetic valve mechanism.

FIG. 4 is a graph showing a relationship between a distance between an electromagnetic coil and a mover and an attractive force of the electromagnetic coil.

[Explanation of symbols]

 6 Mover 8 Displacement Absorber (Displacement Absorber) 10 Valve (Valve Actuator) 22 Valve Seat (Valve Seat) 28 Valve Closing Spring (Valve Closing Energizing Force) 30 Valve Closing Electromagnetic Coil (Electromagnetic Force Generating Means) 32 Valve opening electromagnetic coil (electromagnetic force generating means)

Claims (4)

[Claims] An electromagnetic force generating means for generating an electromagnetic force of a predetermined intensity by applying a predetermined current; a movable element attracted and moved in the forward and reverse directions by the electromagnetic force of the electromagnetic force generating means; A valve urged in a valve closing direction in close contact with the valve seat by the urging force, wherein the valve opens against the valve closing urging force by the movement of the mover in the forward direction. An electromagnetic valve mechanism that closes the valve by the valve closing urging force by the moving operation of the mover in the opposite direction, wherein the moving distance of the mover is fixed, and the movable element is moved between the mover and the valve. An electromagnetic valve mechanism, comprising a displacement absorbing means interposed to absorb a change in position when the valve valve is in close contact with a valve seat. 2. The electromagnetic valve mechanism according to claim 1, wherein the movable element is brought into close contact with the electromagnetic force generating means when the valve is closed. 3. The displacement absorbing means according to claim 1, wherein the displacement absorbing means always applies a pressing force weaker than the valve closing urging force to the movable element to press the valve in a forward direction. Electromagnetic valve train. 4. The displacement absorbing means is extended by the displacement when the valve is displaced in the forward direction in the position change, and is displaced when the valve is displaced in the reverse direction. 4. The electromagnetic valve mechanism according to claim 3, wherein the electromagnetic valve mechanism contracts by an amount corresponding to the contraction.