JPH05248214A - Valve driving device for engine - Google Patents

Abstract

PURPOSE:To obtain a lightweight valve driving device which can generate large driving force. CONSTITUTION:An oscillating body 4 which is prepared by laminating fine plate-like electric conducting wires 6 in a cylindrically formed ceramic is connected to a valve 1. A fixed magnetic pole 7' is further provided for generating a flux which crosses the electric conducting wires 6 in a chain form. Since a plurality of conductors are laminated in the ceramic, a large ampere-turn can be obtained. The oscillating body 4, being made of material other than iron, has a little weight. Thus, a large driving force is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve drive device for an engine, in which the followability of valve opening / closing is improved according to the load condition of the engine.

[0002]

2. Description of the Related Art An ordinary mechanical valve opening / closing apparatus for an engine is driven by an output shaft of the engine and rotates in synchronization with an engine rotation phase. The cam surface of the cam shaft is a shaft of the valve via a rocker arm or a push rod. By pushing the end face, the intake and exhaust valves that are always biased in the closing direction by the spring are opened.

In the above-mentioned valve opening / closing device, a mechanical structure such as a cam shaft and a rocker arm must be attached to the engine, so that the size of the engine becomes large. Further, a part of engine output is consumed due to frictional resistance when driving a mechanism such as a cam, and the effective output of the engine is reduced. Furthermore, in the valve opening / closing device using the cam mechanism described above, the opening / closing timing of the intake and exhaust valves cannot be easily changed during the operation of the engine.

In order to solve the above problem, therefore, the intake and exhaust valves are not opened and closed by a camshaft, but the movable magnetic poles connected to the intake and exhaust valves are attracted by the magnetic force of an electromagnet fixed to the engine side. A valve drive device has been developed which repulsively opens and closes the intake and exhaust valves so that the opening and closing timing can be changed. For example, it is described in Japanese Patent Application No. 63-334959 (Japanese Patent Application Laid-Open No. 2-181007). .

[0005]

In the conventional valve drive system as described above, particularly the valve drive system for driving the exhaust valve requires an extremely large actuating force at the initial stage of valve opening. To increase the driving force, the magnetic force of the permanent magnet must be increased or the ampere turn of the movable magnetic pole must be increased. However, since the location where the valve drive device is arranged is small, it is not possible to arrange a large magnet having a strong magnetic force, and it is also impossible to wind many conductive wires of the coil of the movable magnetic pole. Furthermore, in order to smoothly drive the valve with a small force, it is necessary to reduce the weight of the movable magnetic pole as much as possible, but it is very difficult to realize this.

Therefore, the present invention is intended to provide a valve drive device for an engine which is lightweight and capable of generating a large drive force.

[0007]

In order to solve the above problems, the present invention provides an oscillator for a valve drive device of an engine, which is formed by winding and firing a ceramic green sheet with electric conductor wires printed on its surface. And a fixed magnetic pole for generating a magnetic flux interlinking with an electric conductor wire of the oscillator, and a valve drive device for an engine.

[0008]

A plurality of laminated conductors are provided in a cylindrical ceramic to obtain a large ampere-turn, and the oscillator is light because it does not use an iron core. Therefore, a large driving force is generated.

[0009]

An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, a cylindrical rocking body 4 is attached to an upper end of a valve shaft 2 of a valve 1 via a cotter 3. A plurality of electric conductor wires 6 are laminated inside the oscillator 4, the structure and manufacturing method of which will be described later. On the outer periphery of the oscillator 4, a plurality of fixed magnetic poles 7'are provided in the longitudinal direction of the oscillator 4 across a narrow gap so as to face each other as shown in FIG. Independent fixed coils 8 are wound around these fixed magnetic poles 7 '. The roots of these fixed magnetic poles 7'are attached to the yoke 7 surrounding these outer peripheries. A relay magnetic path 9 made of a columnar soft magnetic material is provided in the cylinder of the rocking body 4 with a certain gap.
The top of the relay magnetic path 9 is attached to the yoke 7 via a supporter 9'made of a magnetic material. 10 is a valve seat. Reference numeral 11 denotes a bush for movably guiding the valve shaft 2 through the cylinder head 12. In addition,
Although not shown, the valve 1 is normally biased in the closing direction by a weak spring.

As shown in FIG. 3, the oscillating body 4 is formed in a cylindrical shape, and is made of, for example, a ceramic body and a magnetic body powder laminated and sintered, and is made of a magnetic conductor. Inside the oscillating body 4, a plurality of movable conductor wires 6 are provided along the circumferential direction.
Are stacked and embedded (exposed on a part of the surface). Two contacts 5 and 5 are provided on the lower portion of the oscillating body 4 over approximately half a circumference. A conducting wire 5 ′ extends laterally and upward from one of the contacts 5, and the movable conductor wire 6 is formed by winding and laminating the plurality of conductors 5 and arranged in the axial direction of the oscillator 4. Both ends of each are connected to the conducting wire 5 '. The conducting wire 5 ′ and the movable conductor wire 6 are embedded in the sintered magnetic conductor forming the oscillator 4. The conducting wire 5'and the movable conductor wire 6 are formed of a good conductor such as copper or silver having a low electric resistance.

FIG. 4 is a sectional view of the oscillator 4, FIG. 5 is a sectional view taken along the line AA of FIG. 4, and FIG. 6 is a block diagram showing electrical connection. As shown in FIGS. 4, 5 and 6,
A brush 14 held by a brush holder 13 slidably contacts the contacts 5 and 5 provided on the rocking body 4. The brush 14 is pressed in the brush holder 13 toward the contact 5 by a spring 15. Reference numeral 16 is a pigtail for reducing the resistance to the power supply to the brush 14. Reference numeral 17 denotes a controller, which controls electric power supplied to the movable conductor wire 6 and the fixed coil 8,
The valve 1 is driven at a predetermined timing. For this reason, signals from sensors provided in the engine are constantly input to the input terminal 17 ', and the optimum timing of valve drive is calculated from these signals. Reference numeral 18 is a battery for supplying electric power to the movable conductor line 6 and fixed coil 8, and 19 is a capacitor for supplying a large current to the movable conductor line 6 and fixed coil 8 within a short time. 9 is a top view showing the arrangement of the brush 14 and the fixed magnetic pole 7'arranged around the oscillator 4. As shown in FIG.

Next, the manufacture of the oscillator 4 will be described.
As shown in FIG. 7, aluminum oxide (Al2 O3) powder was mixed with about 15% of soft magnetic powder, and distilled water and polyvinyl alcohol (PVA) were added and kneaded. One contact portion 5 and the other contact portion 5 are provided by printing, for example, with silver paste, below the left end 21 on the green sheet 20 formed into a film by semi-drying, and the lower end of the one contact portion 5 is provided. Is provided with a tongue portion 22. A plurality of patterns of contact portions 5'and electric conductor wires 6 are printed from the other contact portion 5, and the contact portion 5'at the rightmost end 23 of the green sheet 20 is connected to the lower connecting conductor portion 24. The connecting conductor portion 24, as clearly shown in FIG.
It goes around the back side of the green sheet 20 and is connected to the terminal portion 25 formed there.

The green sheet 20 having the above structure
Is wound in a cylindrical shape from the rightmost end 23 so that the paper surface of FIG. During the winding operation, a paste such as a PVA solution is appropriately applied to fix the wound green sheet so that the green sheet 20 after winding does not become loose.
Then, from the tongue portion 22 of the contact portion 5 to the terminal portion 25 on the back side.
A through-hole is provided toward and a silver paste for electrically connecting the terminal portion 25 and the tongue portion 22 is applied to the inner surface of this through-hole.

An aluminum oxide (Al2 O3) disc having a cotter mounting hole in the center is adhered to the lower surface of the cylindrical intermediate product thus formed, and then known calcination and main calcination are performed. The oscillator 4 having an integral structure is created.

The operation of the embodiment according to the present invention thus constructed will be described. As shown in FIGS. 1 and 2,
When a current is supplied to the fixed coil 8 wound around the fixed magnetic pole 7 ', a magnetic flux is generated in the fixed magnetic pole 7', and this magnetic flux Φ is fixed magnetic pole 7 ', a yoke 7, a supporter 7', a relay magnetic path 9, a fixed magnetic flux. It flows along the route of the magnetic pole 7 '. The flow of this magnetic flux is shown by an arrow A in FIG. If a current is supplied between the brushes 14 in this state, and this current flows in the direction of arrow B in FIG. 9 (hereinafter, this current direction is referred to as the forward direction), the current also flows to the movable conductor line 6 arranged in the gap. Flows. Therefore, a force according to Fleming's left-hand rule is generated in the movable conductor wire 6, and this force acts to move the oscillating body 4 from the front side of the paper surface of FIG. And this force is valve 1
And press it down to open the exhaust port or intake port.
The strength of the force acting on the valve 1 is adjusted by adjusting the amounts of the current flowing through the movable conductor wire 6 provided on the oscillator 4 and the current flowing through the fixed coil 8 wound around the fixed magnetic pole 7 '. .. For example, when trying to open the exhaust valve, a large internal pressure in the combustion chamber is applied to this, and thus a large force against this force is required. In the present invention, at the initial stage of opening the exhaust valve, a large current is instantaneously supplied from the capacitor 19 to the movable conductor wire 6 and / or the fixed coil 8 to open the exhaust valve at once.

Further, after the valve is opened, the valve drive does not require a large driving force unlike when the valve is opened. In the present invention, the current flowing through the movable conductor line 6 is reduced and the driving force is adjusted. Although the valve stops for a predetermined time at the completely opened position, an electric current in the opposite direction is applied to the immediately preceding movable conductor wire 6 to apply a braking force to the movable conductor wire 6 to stop the valve smoothly.
After that, if a predetermined amount of forward current is applied to the movable conductor wire 6 to balance it with the force of the spring biasing in the closing direction, the valve stops at the fully open position.

At the stage of closing the valve 1, the direction of the current flowing through the movable conductor line 6 is reversed. Then, a short time before the valve is seated, a forward current is applied to the movable conductor wire 6 to exert a braking force on the valve, and the valve is softly seated on the valve seat 10.

The controller 17 controls the direction and amount of the current flowing through the movable conductor wire 6 and the direction and amount of the current flowing through the fixed coil 8. Explaining an example of the control, the controller 17 constantly detects the engine load and the rotation phase of the engine during engine operation.
Then, the valve opening / closing timing and the lift amount corresponding to the engine load are calculated. Then, when the valve opening timing comes during the rotation of the engine, the controller 17 outputs an initial signal to execute a valve driving program (not shown) to supply a large current to the movable conductor line 6 to start the operation. Open the valve. After the valve is opened at the initial stage, the amount of current flowing through the movable conductor wire 6 is reduced and the valve is opened with a predetermined lift amount. Next, when closing the valve, a braking force is applied to the fixed coil 8 before the valve is seated, and the valve is softly seated on the valve seat 10.

In the above embodiment, the exciting magnetic flux flows from the relay magnetic path 9 in the fixed magnetic pole 7'direction or in the opposite direction. In FIG. 9, one fixed magnetic pole 7'is used. When the magnetic flux is to flow through the relay magnetic path 9 in the direction of the other fixed magnetic pole 7 ', it is necessary to reverse the directions of the currents flowing through the one gap and the other gap. In such a case, as shown in FIG. 10, a green sheet on which a conductor pattern shown by a solid line is printed on the front side and a conductor pattern shown by a dotted line is printed on the back side is wound into a cylindrical shape and sintered. You can use one.

[0020]

As described in detail above, according to the present invention, since the oscillating body is formed by laminating the thin flat electric conductor wires in the cylindrical ceramics, the ampere turn of the oscillating body is formed. Can be secured large, and since the rocking body has no iron core, it is lightweight and can generate a large driving force.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of the present invention.

FIG. 3 is a perspective view in which a part of the oscillator is cut away.

FIG. 4 is a sectional view of an oscillating body.

5 is a sectional view taken along line AA in FIG.

FIG. 6 is a block diagram showing electrical connection of the present invention.

FIG. 7 is a front view showing a conductive pattern printed on a green sheet.

FIG. 8 is a partially enlarged view of an end portion of a green sheet.

FIG. 9 is a top view showing an arrangement of brushes and fixed magnetic poles arranged around the oscillator.

FIG. 10 is a front view showing a conductive pattern of another embodiment printed on a green sheet.

[Explanation of symbols] 1 …… Valve 2 …… Valve shaft 3 …… Cotter 4 …… Oscillator 5 …… Contactor 5 ′ …… Current line 6 …… Movable conductor line 7 …… Yoke 7 ′ …… Fixed magnetic pole 8 ... Fixed coil 9 ... Relay magnetic path 9 '... Supporter 10 ... Valve seat 11 ... Bushing 12 ... Cylinder head 13 ... Brush holder 14 ... Brush 15 ... Spring 16 ... Pigtail 17 ... Controller 18 ... Battery 19 ... Capacitor 20 ... Green sheet 21 ... Left end 22 ... Tongue 23 ... Rightmost end 24 ... Connecting conductor 25 ... Terminal

Claims (1)

[Claims] 1. A valve drive device for an engine, wherein an oscillator formed by winding and firing a ceramic green sheet on which electric conductor wires are printed is connected to a valve, and an electric conductor wire of the oscillator is used. A valve drive device for an engine, comprising a fixed magnetic pole for generating interlinking magnetic flux.