JP2802540B2 - Electromagnetic valve drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic valve driving device that drives an intake and exhaust valve of an engine to open and close by an electromagnetic force.

(Prior art) A conventional intake / exhaust valve opening / closing drive device is driven by an output shaft of an engine and rotates from a cam surface of a camshaft that is synchronized with an engine rotation phase through a link mechanism such as a rocker arm or a pushing rod. By pressing the shaft end face of the valve, the intake and exhaust valves constantly biased in the closing direction by a spring are driven to open and close.

Since the camshaft and the link mechanism must be attached to the engine as described above, the opening / closing drive device has a large engine shape. Further, a part of the engine output is consumed due to frictional resistance when the camshaft and the link mechanism are driven, and the effective output of the engine is reduced.

Further, since the opening / closing timing of the intake / exhaust valve cannot be easily changed during the operation of the engine, the valve opening / closing timing must be adjusted so as to be in an optimal operating state at the time of operation at a predetermined engine rotation speed. Therefore, when the engine is operated at a rotation speed different from the predetermined rotation speed, there is a problem that the output and efficiency that the engine can originally exhibit cannot be obtained.

Therefore, in order to solve the above problem, an alternating magnetic field is applied to a secondary coil connected to the intake / exhaust valve, instead of opening / closing the intake / exhaust valve using a camshaft. There have been proposed many valve driving devices for opening and closing an intake / exhaust valve by an electromagnetic force received from the alternating magnetic field, and have already been filed by the present applicant as Japanese Patent Application No. 1-226719.

(Problems to be Solved by the Invention) In the valve drive device for opening and closing the intake and exhaust valves by the conventional electromagnetic force as described above, a member that holds the secondary coil and connects the secondary coil to the intake and exhaust valve. Is formed of a magnetic material in order to increase the density of the magnetic flux linked with the secondary coil.

However, since the magnetic material has a large specific weight,
The weight of the member connecting the secondary coil and the intake / exhaust valve increases. Therefore, since the inertial mass of the reciprocating drive system of the intake and exhaust valves increases, the acceleration at the time of reciprocal drive of the intake and exhaust valves is suppressed, and there is a problem that the engine cannot be operated at high speed.

The present invention has been made in view of the above points, and an object of the present invention is to provide an electromagnetic valve drive device that reduces the inertial mass of a reciprocating drive system of intake and exhaust valves and enables operation in a high-speed rotation region of an engine. Is what you do.

(Means for Solving the Problems) According to the present invention, the action between the magnetic flux from the primary coil fixed to the engine and the current induced in the reciprocable secondary coil connected to the intake and exhaust valves. An electromagnetic force driving device that drives the intake / exhaust valve by an electromagnetic force generated by the magnetic head, wherein a gap provided in the middle of a magnetic flux path from the primary coil and a composite material of powdered magnetic material and plastic are provided. And a movable element that forms a part of the magnetic flux path and includes the secondary coil.

(Operation) In the electromagnetic valve drive device of the present invention, the member connecting the secondary coil and the intake / exhaust valve is formed by a composite member of powder of a magnetic material and plastic.

For example, when a powder made of short fibers or fine particles of silicon steel is used as the magnetic substance powder, the specific weight of the silicon steel is about
7.8 g / cm ² and the specific weight of plastic is about 1.2 g / c
m ² , the specific weight of the composite material obtained by mixing the two at a volume ratio of 1: 1 is about 4.5 g / cm ² .

Therefore, the inertial mass of the reciprocating drive system of the intake and exhaust valves is reduced.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a driving device according to the present invention, and FIG. 2 is a view taken along the line II-II. By the way, the engine is provided with the intake valve and the exhaust valve as described above. However, since the drive device according to the present invention can be applied to both the intake and exhaust valves, a device mainly for opening and closing the intake valve will be described below.

Reference numeral 1 denotes an intake valve made of a ceramic material such as silicon nitride which is lightweight and has excellent high-temperature strength. The intake valve 1
A disk-shaped movable magnetic pole 11 is in contact with an end of the shaft.
The thickness of the movable magnetic pole 11 is formed so as to decrease from the center toward the periphery. The intake valve 1 is reciprocally supported by a valve guide 12. When the intake valve 1 is closed, an umbrella portion of the intake valve 1 is seated on a valve seat 14 to close an intake port.

A mover 2 to be described later is connected to a portion near the center of the shaft of the intake valve 1. In order to prevent the intake valve 1 from lowering when the engine is stopped, the mover 2
Is biased in the closing direction by a spring 13.

Reference numeral 3 denotes a driving unit. An annular fixed magnetic pole 31 facing the center of the lower surface of the movable magnetic pole 11 and an annular fixed magnetic pole 32 facing the outer peripheral part of the movable magnetic pole 11 are provided at the upper end of the driving unit 3 in the drawing. . The fixed magnetic pole 31 and the fixed magnetic pole 32 are arranged concentrically, and an excitation coil 33 for exciting the fixed magnetic pole 31 and the fixed magnetic pole 32 is provided between the fixed magnetic pole 31 and the fixed magnetic pole 32. ing.

The fixed magnetic pole 31 is provided around the shaft outer peripheral surface of the intake valve 1 with a small space therebetween, and a central magnetic pole 34 is provided to extend below the fixed magnetic pole 31.

The center magnetic pole 34 is formed in a cylindrical shape, and is provided at a position surrounding the shaft of the intake valve 1. The outer peripheral surface of the central magnetic pole 34 faces the inner peripheral surface of the mover 2.

The drive section 3 is further provided with a plurality of stator magnetic poles 35 facing the outer peripheral surface of the central magnetic pole 34 via the mover 2, that is, facing the outer peripheral surface of the mover 2. The stator magnetic poles 35 face the entire outer peripheral surface of the mover 2 and are provided in a plurality of stages in the reciprocating direction of the mover 2. A primary coil 36 is wound around the stator magnetic pole 35, and the magnetic flux density and the direction of the magnetic flux passing through the stator magnetic pole 35 can be controlled for each stage.

Reference numeral 4 denotes a controller, which is an input / output interface that controls input and output of signals, a ROM that stores programs and various relationship maps in advance, a CPU that performs calculations in accordance with programs stored in the ROM, and temporarily stores calculation results and data. RA
M, a control memory for controlling the flow of signals inside the controller 5, and the like.

The controller 4 includes an initial driving device 41 and a speed adjusting device.
42 is connected. The initial drive device 41 is connected to the excitation coil 33, and when the control signal is input from the controller 4, supplies power to the excitation coil 33 to excite the fixed magnetic pole 31 and the fixed magnetic pole 32. .

Further, the speed adjusting device 42 is connected to each stage of the primary coil 36, and when a speed control signal is input from the controller 4, an alternating current having a different phase for each stage of the primary coil 36 is provided. Power is supplied, a traveling magnetic field is formed by the magnetic flux passing through the stator magnetic pole 35, and the traveling speed and traveling direction of the traveling magnetic field are controlled.

 Next, the mover 2 will be described.

 FIG. 3 is a sectional perspective view of the mover.

The mover 2 is formed in a cup shape, that is, a cylindrical shape with a bottom, and has a core 21 made of a composite material of magnetic powder and plastic, held by the core 21 and connected to the intake valve 22. And a plurality of closed annular secondary coils 22.

The magnetic material powder contained in the core 21 is, for example, short fibers of silicon steel or fine particles of silicon steel, and is obtained by mixing a plastic powder with a silicon steel powder or a soft iron powder. And the plastic are completely and uniformly kneaded, and the movable member 2 is formed by filling the kneaded material in a mold in which the secondary coil 22 is arranged at a predetermined position by the support member 23.

After mixing the thermoplastic powder and the magnetic powder and filling the mold, heating is the most suitable method for uniform mixing. Lightweight mixtures can be formed.

Since the secondary coil 22 is required to be lightweight, the secondary coil 22 is made of, for example, a metal material or conductive ceramic having conductivity and small specific weight such as aluminum.

The secondary coil 22 may be connected between the coils by a thin support member 23 and filled with a plastic mixture therebetween.

Therefore, the mover 2 thus manufactured is lightweight and excellent in magnetic permeability, and can significantly reduce the inertial mass of the reciprocating drive system of the intake valve 1.

Next, the operation of the device of the present invention having the above-described configuration will be described.

During the operation of the engine, the controller 4 constantly detects the engine load and the rotational phase of the engine. Then, the opening / closing timing and lift amount of the intake valve corresponding to the engine load are calculated.

Then, when the actual rotation phase of the engine reaches the calculated intake valve opening timing, the controller 4 outputs a control signal to the initial drive device 41. Then, power is supplied to the exciting coil 33 as described above, and the fixed magnetic pole 31 and the fixed magnetic pole 32 are excited. FIG. 4 shows a state where the fixed magnetic pole 31 is excited to the S pole and the fixed magnetic pole 32 is excited to the N pole.

FIG. 4 is a diagram showing a state of magnetic flux acting on the movable magnetic pole.

In the figure, the arrow indicated by B indicates the flow of the magnetic flux.
As shown in the figure, the magnetic flux emitted from the fixed magnetic pole 32 is a movable magnetic pole.
A magnetic path is formed that passes through the inside of 11 and flows to the fixed magnetic pole 31.
Therefore, the movable magnetic pole 11 is attracted by the fixed magnetic pole 31 and the fixed magnetic pole 32, and drives the intake valve 1 in the opening direction.

If the thickness of the movable magnetic pole 11 is constant,
Since the internal magnetic flux density is less at the outer periphery than at the center,
As shown in this figure, even if the plate pressure at the outer peripheral portion is reduced and the magnetic flux density at the central portion and the outer peripheral portion is made constant, the attraction force does not decrease at all.

Since the inertial mass of the reciprocating drive system of the intake valve 1 is reduced by reducing the plate pressure in this manner, a larger acceleration can be realized.

As described above, when the power is supplied to the excitation coil 33 and the intake valve 1 is initially driven, the intake valve 1 is driven up to the calculated lift amount, and the intake valve 1 is further closed at the calculated closing timing. Adjust the moving speed of the intake valve 1 so that it sits at 14. The adjustment of the moving speed is performed by the controller 4 through the speed adjusting device 42 as described above.
This is done by outputting a speed control signal.

The bias force of the spring 14 for holding the intake valve 1 in the closed state is set sufficiently small with respect to the electromagnetic force.

Although the embodiments have been described in detail, various different embodiments can be easily configured without departing from the spirit of the invention, and therefore, the present invention is not limited to the specific embodiments described in the claims. You are not restricted to the examples.

(Effects of the Invention) As described above, according to the present invention, the member connecting the secondary coil and the intake / exhaust valve is formed of a composite member of magnetic powder and plastic, and the reciprocating drive of the intake / exhaust valve is performed. Since the inertial mass of the system is reduced, the intake / exhaust valve can be driven at a large acceleration by the electromagnetic force. Therefore, it is possible to provide an electromagnetic force valve drive device that enables high-efficiency operation in a high-speed rotation region of the engine. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a driving device according to the present invention;
2 is a cross-sectional perspective view of the mover, and FIG. 4 is a view showing a state of magnetic flux acting on the movable magnetic pole. 1 ... intake valve, 2 ... mover, 3 ... drive unit, 4 ...
… Controller, 11… Movable magnetic pole, 21 …… Core, 22 ……
Secondary coil, 36 ... Primary coil.

Claims (4)

(57) [Claims] An intake / exhaust valve is driven by an electromagnetic force acting between a magnetic flux from a primary coil fixed to an engine and a current induced in a reciprocable secondary coil connected to the intake / exhaust valve. An electromagnetic force valve driving device, wherein a gap provided in the middle of a magnetic flux path from the primary coil;
An electromagnetic force, comprising a mover that is made of a composite material of a powder of a magnetic substance and plastic and reciprocates in the gap to form a part of the magnetic flux path and encloses the secondary coil. Valve drive. 2. The electromagnetic valve driving device according to claim 1, wherein said intake / exhaust valve is formed of ceramic which is a lightweight and high-strength material. 3. The electromagnetic valve driving device according to claim 1, wherein the powder of the magnetic material is at least one of short fibers or fine particles of silicon steel. 4. The electromagnetic valve driving device according to claim 1, wherein the gap is provided in a cylindrical shape, and the mover is formed in a cup shape.