Electromagnetically Driven Valve

Abstract

An electromagnetically driven valve includes a driven valve having a stem and carrying out reciprocating motion along a direction in which the stem extends, a disc support base, a lower disc having one end coupled to the stem and the other end supported by the disc support base so as to allow free oscillation of the lower disc and oscillating around a central axis extending at the other end, and a lower torsion bar provided so as to extend along the central axis and fixed to the other end. The lower torsion bar has a fix portion fixed to the disc support base, and a phase angle thereof around the central axis with respect to the disc support base can be adjusted. With such a structure, the driven valve can carry out reciprocating motion in a stable manner, and energy loss can be reduced.

Description

TECHNICAL FIELD [0001] The present invention generally relates to an electromagnetically driven valve, and more particularly to an electromagnetically driven valve of a rotary drive type used in an internal combustion engine and driven by electromagnetic force and elastic force. BACKGROUND ART [0002] Japanese Utility Model Laying-Open No. 61-200919 discloses a knock pin having serration formed on an outer circumferential surface of a pin body along an axial direction thereof In addition, Japanese Utility Model Laying-Open No. 61-200920 discloses a knock pin having an elastic body provided on an outer circumferential surface of a pin body, the elastic body being pressed against and brought in contact with a wall surface of an insertion hole. [0003] Japanese Utility Model Publication No. 14-20004 discloses an apparatus for preventing loosening of a male screw, which includes a male screw threaded on an outer circumference and having a notch in a part of the outer circumference, and a ...

AI Technical Summary

Benefits of technology

[0007] In order to solve the above-described problems, an object of the present invention is to provide an electromagnetically driven valve attaining stable reciprocating motion of the driven valve and reduction in energy loss.

[0009] According to the electromagnetically driven valve structured as above, the fix portion is provided, so that the torsion spring is attached to the supporting member with a phase angle around the axis extending at the other end being adjusted, and fixed to that position. Accordingly, the spring load imposed by the torsion spring onto the oscillating member can accurately be set to a value determined in design. Here, when the oscillating member actually oscillates, no error is produced between the spring load imposed by the torsion spring onto the oscillating member and the spring load calculated in design. Therefore, electromagnetic force based on the spring load in design is applied to the oscillating member, whereby stable reciprocating motion of the driven valve is achieved. As it is not necessary to apply the electromagnetic force for eliminating the error in the spring load, waste of electric power in the electromagnetically driven valve can be prevented.

[0011] Preferably, the fix portion includes an outer circumferential surface of the torsion spring, having serration formed. The supporting member has an opening for receiving the fix portion. An inner wall of the opening has serration formed, which is engaged with the serration formed on the fix portion. According to the electromagnetically driven valve structured as above, engagement between the serration formed on the outer circumferential surface of the torsion spring and the serration formed on the inner wall of the opening is shifted, so that a phase angle of the torsion spring around the axis with respect to the supporting member can be adjusted. In addition, as engagement between the serrations is strong, the torsion spring can further reliably be fixed in the adjusted position.

[0012] Preferably, the fix portion includes an outer circumferential surface of the torsion spring, implemented as a tapered surface. The supporting member has an opening for receiving the fix portion. An inner wall of the opening has a tapered surface formed, which is pressed against and brought in contact with the tapered surface formed on the fix portion. According to the electromagnetically driven valve structured as above, the torsion spring is pressed into the opening with the tapered surfaces being slid, so that a phase angle of the torsion spring around the axis with respect to the supporting member can arbitrarily be adjusted. In addition, as wedge force is produced between the outer circumferential surface of the torsion spring and the inner wall of the opening, the torsion spring can reliably be fixed in the adjusted position. Moreover, the outer circumferential surface of the torsion spring should only be tapered. Therefore, even if workability of the torsion spring is poor, such a shape can readily be obtained.

[0013] Preferably, the fix portion includes an outer circumferential surface of the torsion spring, having a male screw formed. The supporting member has an opening for receiving the fix portion. An inner wall of the opening has a female screw formed such that the male screw formed on the fix portion is screwed in. A locknut is fastened to the opening from a side opposite to a direction in which the fix portion is inserted. According to the electromagnetically driven valve structured as above, an angle for the torsion spring to be screwed into the opening is modified, so that a phase angle of the torsion spring around the axis with respect to the supporting member can arbitrarily be adjusted. In addition, loosening of the torsion spring can be prevented by repulsive force produced between the locknut and the torsion spring. Accordingly, the torsion spring can reliably be fixed in the adjusted position.

[0014] As described above, according to the present invention, an electromagnetically driven valve attaining stable reciprocating motion of the driven valve and reduction in energy loss can be provided.

Problems solved by technology

On the other hand, in the torsion bar and the helical spring, error in shape inevitable in the manufacturing step or assembly error with respect to the disc support base or the stem is produced, which results in failure in accurate setting of the disc to the intermediate position.

In such a case, error in spring load imposed on the driven valve at each lift position is produced, and accurate electromagnetic force for overcoming the spring load cannot be calculated.

Then, movement of the driven valve becomes unstable, a speed of the valve when seated (sound produced from operation) is high, or electric power for correcting such error is wasted in the electromagnet.

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