JP2673370B2 - Valve drive - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve drive device that drives a valve for controlling engine supply / exhaust with a linear pulse motor.

(Prior Art) A normal engine intake / exhaust valve opening / closing drive device has a camshaft and a link mechanism attached to the engine, and as a result, the size of the engine increases. Further, since the camshaft is driven by the output shaft of the engine, a part of the engine output is consumed due to frictional resistance when driving the camshaft and the link mechanism, and the effective output of the engine is reduced. Further, it is difficult to change the opening / closing timing of the intake / exhaust valves according to the engine speed. Since the valve opening / closing timing is adjusted in advance according to the specific engine speed, the engine operates at high speed or low speed. When this happens, a reduction in engine power and efficiency is unavoidable.

The above problem can be solved by opening and closing the intake and exhaust valves by an electromagnet without using a camshaft. Such a valve driving device is disclosed in Japanese Patent Application Laid-Open No. 58-183805,
Alternatively, it is described in JP-A-61-76713.

(Problems to be Solved by the Invention) A movable magnetic pole is formed on a shaft of a valve that controls the supply and exhaust of the engine, and the shaft is reciprocated by a magnetic force acting between the magnetic pole fixed to the engine to open and close the valve. The valve drive device that controls the intake and exhaust valves can be controlled with a small driving force during the opening and closing operations, but must be driven against the internal pressure of the cylinder at the start of the opening operation,
Generally, a large driving force in the opening direction is required.

However, in the configuration of the electromagnet disclosed in the device described in the above-mentioned 2 gazette, the distance between the electromagnet and the magnetic body changes as the intake / exhaust valve is driven, and the electromagnetic force abruptly changes so that the intake / exhaust valve operates. It has the drawback of being extremely unstable.

The present invention has been made to solve the above-described problems, and the intake / exhaust valve of an engine is opened / closed by a linear pulse motor arranged at the shaft end of the intake / exhaust valve, not by a camshaft. Open and close the valve,
In particular, it is an object of the present invention to provide a valve driving device that is small in size and can control opening and closing with a large driving force.

(Means for Solving the Problems) According to the present invention, a movable magnetic pole is formed on a shaft of a valve that controls intake and exhaust of an engine, and a magnetic force acting between the fixed magnetic pole fixed to the engine and the movable magnetic pole. In a valve driving device for controlling opening and closing of a valve by reciprocating the shaft by means of a valve, the valve is attached to a movable shaft of the valve, and an N pole and an S pole are provided at intervals in the longitudinal direction of the shaft.
A movable magnetic pole composed of permanent magnets in which poles are arranged, an annular fixed magnetic pole that surrounds the movable magnetic pole in an annular shape and faces the movable magnetic pole with a gap, a pole extending outward from the fixed magnetic pole, and a plurality of poles formed between the poles. A ring magnetic body having a slot is laminated in the longitudinal direction of the shaft with a space provided, and a core for magnetically connecting the tips of the poles and an excitation winding wound around the poles are provided. And a fixed magnetic pole composed of an electromagnet fixed to the movable magnetic pole, and a driving force is applied to the movable magnetic pole by exciting the exciting winding.

(Operation) In the valve drive device of the present invention, the driving force for the intake / exhaust valve does not change due to the opening / closing movement, stable opening / closing operation can be performed, and the annular magnetic body arranged on the outer periphery of the shaft has the excitation winding. The magnetic force acting on the shaft from the fixed magnetic pole can be set sufficiently large because it is wound around the outer slot and the polarity of the inner peripheral surface is changed.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

 FIG. 1 is a block diagram showing one embodiment of the present invention.

Reference numeral 1 denotes an exhaust valve formed of a high-strength lightweight material such as ceramics. A circular permanent magnet 2 forming a movable magnetic pole is fitted to the upper end of a shaft for controlling engine exhaust. ing. The shaft end of the exhaust valve 1 is covered with a magnetic passage 21 made of a cylindrical magnetic body, and a fixed magnetic pole formed by an electromagnet 3 fixed to the engine is formed on the outer periphery of the magnetic passage 21. Has been done. This electromagnet 3 has a plurality of annular magnetic bodies 31, 32, 33, 3 having inner walls that form fixed magnetic poles and outer slots.
4 are laminated and arranged on the outer peripheral surface of the shaft at a predetermined interval. The magnetism of the electromagnet 3 is controlled to be changed by a constant pitch according to the excitation condition set in the excitation winding wound in the slot of the annular magnetic body 31 and the like, and acts as a slider driving portion of the linear pulse motor. Is. A position sensor 4 that detects the moving position of the exhaust valve 1 and outputs a position signal is installed in the electromagnet 3. The position sensor 4 includes an engine 6
Is connected to a control unit 5 for electronically controlling the.

Reference numeral 10 is an upper electromagnet that constitutes an accelerating means for accelerating the opening operation of the exhaust valve 1. The coil of the upper electromagnet 10 is a rotating arm that strikes the upper end surface of the exhaust valve 1 to accelerate it. It is configured to suck 101 and give a large acceleration required for the opening operation of the exhaust valve 1 in accordance with the engine speed. That is, in the exhaust valve 1, the shaft portion is supported by the valve guide 8 with respect to the engine 6 so as to be capable of reciprocating in the axial direction, and the valve seat 81 is disposed at the exhaust port which is the starting point of the exhaust pipe line of the engine 6. The umbrella portion of the exhaust valve 1 and the valve seat 81 are in close contact with each other to close the exhaust port. Then, in the vicinity of the output shaft of the engine 6, a rotation sensor 9 for detecting the rotation speed and the rotation phase of the output shaft and converting them into a signal.
Are arranged. The rotation sensor 9 detects the crank angle of the engine 6, and the control unit 5 determines the opening timing of the exhaust valve 1. The control unit 5 controls the upper electromagnet 10 according to the rotation speed of the engine 6 to control the acceleration of the exhaust valve 1. The striking surface of the rotating arm 101 is covered with high-toughness ceramics such as zirconia, and the striking seat 12 made of the same kind of ceramics is also arranged on the upper end surface of the exhaust valve 1. Further, since the rotating arm 101 is in constant contact with the striking seat 12 by the spring 102, the impact at the time of striking is mitigated, the striking sound is reduced, and the destruction of the ceramic part can be prevented.

An intake / exhaust valve for controlling the opening / closing of a plurality of intake / exhaust ports having the same configuration as the exhaust valve 1 is provided in the engine 6, and the shaft is formed by a magnetic force acting between an electromagnet fixed to the engine. To reciprocate to control the opening and closing of the valve. That is, in the permanent magnet 2, magnets 22 and 23 are juxtaposed at a predetermined interval P in the axial direction of the exhaust valve 1, the shaft end side is an N pole 22 and the other is an S pole 23. The electromagnets 3 facing the magnetic poles 22 and 23 of the permanent magnet 2 are four annular magnetic bodies 31, 32, 33 and 34 arranged in parallel in the moving direction of the permanent magnet 2 with an interval of (4/3) P. It is composed of a fixed magnetic pole 35 facing the outer peripheral surface of the magnetic path 21, and coils 36, 37, 38, 39 in the excitation windings wound in the respective slots of the annular magnetic bodies 31, 32, 33, 34. Coil 36, coil 38 and coil 37 of the excitation winding
The winding directions of the coil 39 and the coil 39 are opposite to each other.

A spring 11 is provided between the magnetic passage 21 and the valve guide 8 to prevent the exhaust valve 1 from lowering when the electromagnet 3 is not operated. In addition to the input / output interface 54, the control unit 5 has a RAM 53 for temporarily storing data and calculation results, a ROM 52 for storing programs and various relationship maps, a CPU 51 for performing calculations under programs stored in the ROM 52, The control unit 5 includes a control memory 55 for controlling a signal flow inside the control unit 5 and the like. The control unit 5 outputs a drive signal for the exhaust valve 1 as a coil.
The signal S1 is output to the coil 36 and the coil 38, and the coil 37 and the coil
The signal S2 is output to 39, and the signal S3 is output to the upper electromagnet 10.

FIG. 2 is a diagram showing an example of the structure of the electromagnet 3.

FIG. 3A is a front view showing the shape of one annular magnetic body 31. The inner peripheral surface of the annular magnetic body 31 has a facing area of the shaft of the valve 1 facing the movable magnetic pole as large as possible to allow the magnetic flux to act efficiently. Therefore, it does not have a wasteful part such as a slot. That is, on the outer peripheral side of the annular magnetic body 31, a plurality of poles 31b for winding a coil serving as an excitation winding and slots 31a for accommodating the excitation coil are formed at equal intervals. A coil 36, which is an exciting winding, is wound around the pole 31b in a predetermined direction so that the inside of the annular magnetic body 31 becomes an S pole or an N pole when energized in these slots 31a to form the annular magnetic body 31. (Fig. 3). Hereinafter, the annular magnetic bodies 32, 33, 34 are similarly constructed. Then, as shown in FIG. 2B, these annular magnetic bodies are press-fitted into the cylindrical outer peripheral core 42 through a spacer 41 made of, for example, a synthetic resin to form the electromagnet 3 serving as a fixed magnetic pole. , Fix this to the engine.

Next, the operation of the present invention will be described with reference to FIG.

When no current is flowing through the coils 36, 37, 38, 39, the exhaust valve 1 is moved up to the position shown in FIG. 1 by the force of the spring 11 and the exhaust port 50 is closed. When the exhaust port 50 is released, the signal S1 in the positive direction is transmitted to the coils 36, 38 of the annular magnetic bodies 31, 33.
In addition, the signal S2 in the positive direction is transmitted to the coils 37, 39 of the annular magnetic bodies 32, 34.
It is assumed that magnetic poles are generated in the poles of each of the four annular magnetic bodies as shown in (a) and (b) of FIG. 4 (note that in order to avoid complication in FIG. The code is omitted.). By applying these signals, the magnetic poles 22,2
3 is driven downward. When the magnetic poles 22 and 23 are lowered to the position (c) in FIG. 4, the signal S1 is cut off and the signal S2 in the negative direction is applied to the coils 37 and 39 of the annular magnetic bodies 32 and 34 at the same time. The magnetic poles 22 and 23 continue to descend due to the excitation of the annular magnetic bodies 32 and 34, and when they descend to the position of FIG. 4 (d), the excitation of the annular magnetic bodies 32 and 34 remains the same and A negative direction signal S1 is applied to the coils 36 and 38. By applying these signals, the magnetic poles 22 and 23 pass through the position shown in FIG.
It descends to the position shown in Figure (f). At this time, the signal S2 is cut off, and at the same time, the signal S1 in the positive direction is applied to the coils of the annular magnetic bodies 31, 33.
Apply to 36 and 38. The magnetic poles 22, 2 are excited by the excitation of the annular magnetic body 33.
3 continues to descend, passes through the position of FIG. 4 (g), descends to the position of FIG. 4 (h), and the operation of the magnetic poles 22 and 23 is stopped.
When moving the exhaust valve 1 upward, power supply to all the coils of the annular magnetic body is stopped. Then, the exhaust valve 1 returns to the state shown in FIG. 1 by the force of the spring 11.

In this way, the annular magnetic body 31 arranged on the outer periphery of the valve 1
Since a sufficiently large magnetic flux passage area is secured inside, the magnetic force acting on the movable magnetic pole on the valve 1 side can be set sufficiently large, and even when the intake / exhaust valve is configured to be small,
The valve can be opened and closed with a large driving force.

Here, the exhaust valve has been described, but the drive device according to the present invention can be similarly applied to the intake valve.

Although the present invention has been described above in some detail with reference to its most preferred embodiments, the description of the preferred embodiments does not contradict the spirit of the present invention described in the modifications of the detailed configuration and the claims. Obviously, various modifications and combinations thereof can be applied.

(Effects of the Invention) As described above, according to the present invention, the opening / closing drive of the intake / exhaust valve of the engine is performed by the linear pulse motor arranged at the shaft end portion of the intake / exhaust valve, not by the camshaft. It is possible to provide a valve drive device that can perform opening / closing driving of an exhaust valve, and in particular, can control opening / closing of an intake / exhaust valve with a small size and a large driving force.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of fixed magnetic poles fixed to an engine, and FIG. 3 is a winding state of a coil around an annular magnetic body. Plan view,
FIGS. 4A to 4H are operation explanatory views for explaining the operation of the fixed magnetic pole. 1 ... Exhaust valve, 2 ... Permanent magnet, 3 ... Electromagnet, 3
1,32,33,34 …… annular magnetic material, 36,37,38,39 …… excitation winding, 31a …… slot.

Claims (1)

(57) [Claims] 1. A movable magnetic pole is formed on a shaft of a valve for controlling intake and exhaust of an engine, and the magnetic force acting between the fixed magnetic pole fixed to the engine and the movable magnetic pole reciprocates the shaft to open and close the valve. In a valve drive device to be controlled, a movable magnetic pole, which is attached to a movable shaft of the valve and is composed of a permanent magnet having an N pole and an S pole arranged at intervals in the longitudinal direction of the shaft, and the movable magnetic pole is formed in an annular shape. An annular magnetic body having an annular fixed magnetic pole that surrounds the magnetic pole and faces with a gap therebetween, a pole that extends outward from the magnetic pole, and a plurality of slots formed between the poles are provided at intervals to provide a longitudinal direction of the shaft. Fixed magnetic pole composed of an electromagnet fixed to the engine, which is composed of a core that is magnetically connected between the tips of the poles and an excitation winding that is wound around the poles. If, consists, drive the valve, characterized in that allowed to impart driving force to the movable magnetic pole by the excitation of the excitation winding.