JPS5815664B2 - Solenoid proportional valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an oscillating type electromagnetic proportional valve that can proportionally control a flow rate by changing the current of an excitation coil.

Conventional configuration and its problems Conventional electromagnetic proportional valves include a plunger type in which the plunger is held non-slidingly against a fixed member by a plate spring, but there are two parts in the magnetic path. Because of the air gaps, the magnetic efficiency was not necessarily good, and there was a limit to the miniaturization of electromagnetic coils.

Therefore, as a solenoid valve that has only one gap in the magnetic path and has good magnetic efficiency, there is a fulcrum-supported swing type solenoid valve, but it is not a proportional valve.

That is, an example of the basic configuration of this swing type solenoid valve is shown in FIG.

Figure 1 shows an example of a conventional solenoid valve, where a is an exciting coil b
The iron core C inserted through the center is an armature that attracts and separates from the iron core a under the action of a return spring d, and a valve f for opening and closing the valve seat e is attached to one end of this armature.

In the one shown in Fig. 1 above, the valve f simply opens and closes the valve seat e by excitation and demagnetization of the excitation coil b, and the flow rate is 0N-OF.
Only F control was possible.

Moreover, in this structure, since the armature 114 and the arm 115, which are movable members, are provided so as to face the inside of the fluid passage,
The fluid passage is not isolated from live parts such as the excitation coil 112 and iron core 101, and the fluid comes into contact with the live parts, so in the event of an abnormality such as an electric spark occurring in the live part, an explosion could occur if the fluid is a flammable gas. It's scary and unsafe.

As a countermeasure against this, in the plunger-type solenoid valves mentioned above, a sealing membrane such as a flexible diaphragm is used to isolate the live parts on the fluid passage. Since the arm 115 moves in the lateral direction, it is difficult to use a diaphragm or the like as in a plunger type.

Although it is possible to mold the live part, the sealing reliability of the mold is not sufficient.

Furthermore, the use of the flexible sealing film has a risk of breakage, and there are also problems in terms of reliability for long-term use.

Although it is not publicly known, there is a swing type electromagnetic proportional valve that solves these problems, but there is a patent application No. 51-148236 (prior application). The electromagnetic coil portion is provided outside of the fluid passage by fixing the yoke and having the tip of the yoke pass through the mounting plate and facing into the fluid passage.

However, it is not easy to create a completely airtight structure in the part where the plate-shaped yoke passes through the mounting plate because the plate-shaped yoke does not allow the use of sealing means such as an O-ring.

Technical Problems of the Invention The present invention provides a swing-type solenoid valve that can be miniaturized, which enables proportional control and improves safety and reliability by locating a charging part such as a solenoid coil outside the fluid passage. In addition, the magnetic path forming member has a circular cross section so that the portion penetrating the base forming the fluid passage can be easily sealed.

Technical Means of the Invention The present invention provides an excitation coil with an iron core having a circular cross section, penetrates the notched magnetic pole end of the iron core as a base, seals this penetration with an O-ring, and fixes the other end to a yoke plate. A yoke frame with a circular cross section is fixedly connected to the yoke plate, and the other end of the yoke frame passes through the base, and this penetrating part is sealed with an O-ring.A yoke piece is fixed to the tip of the yoke frame, and the end of the yoke piece is approximately The armature is made into a rectangular shape and meshes with the approximately V-shaped groove of the armature to form a fulcrum support part.A valve is provided at one end of the armature, and a return spring is latched at the other end, so that the end of the armature on the iron core side is approximately The notched magnetic pole part is configured to swing within the notched magnetic pole part of the iron core, and the notched magnetic pole part has an inclined surface so that the gap between the two is narrowed when the armature is attracted and rotated. .

By energizing the working excitation coil of the invention, the armature rotates in a state where the forces of the core, the magnetic attraction force, and the return spring are balanced.

As the armature rotates, the air gap with the iron core narrows and the magnetic flux increases, but the ratio of the magnetic flux component that contributes to rotation to the magnetic flux component that does not contribute to rotation (pulls each other), or the former becomes larger than the latter. On the other hand, since it gradually decreases, the magnetic flux of the component contributing to rotation can be kept almost constant.

That is, the attraction force can be made even with respect to the rotational stroke of the armature.

Since the force of the spring is proportional to the stroke, the armature rotates to a stroke position determined by the intersection of the attractive force characteristic curve and the spring force characteristic curve depending on the amount of current applied to the excitation coil.

Therefore, the operation of the armature, that is, the opening degree of the valve, can be obtained in proportion to the amount of energization.

Further, the electromagnetic coil portion and the fluid passage are isolated, and the core and the base penetrating portion of the yoke frame are easily and reliably sealed.

Structure of the Embodiment In FIG. 2, reference numeral 1 denotes an iron core having a circular cross section and having a notch A at one end, which passes through a base 2 made of aluminum die-casting.

3 is an excitation coil; 4 is a yoke frame having a circular cross section; like the iron core 1, a yoke piece 5 that passes through the base 2 and has a square portion at one end is fixed with screws 6;

7 is a yoke plate that connects the iron core 1 and the yoke frame 4, and screws 8 and 9
They are each fixed in place.

10 is a screw for fixing the iron core 1 and the yoke frame 4 to the base 2 via the yoke plate 7.

Reference numeral 11 denotes a contact terminal, which has a substantially ■-shaped groove in a part thereof and meshes with the square part of the yoke piece 5 to form a fulcrum, and furthermore, a suction piece 12 is connected to a valve fitting 13 in a part near the iron core 1. It is clamped and fixed with a stopper 14, a return spring 15 is hooked to the other end, and a spring force adjustment screw 16, an adjustment screw guide plate 17, and a nut 18 are provided, so that the spring force acting on the armature 11 can be adjusted. After adjustment, the blank lid 19 is adhesively press-fitted and sealed.

Reference numerals 20 and 21 are O-rings, and 22 is a metal fitting that also serves as an O-ring presser stopper, and is fixed with screws 23.

24 is a metal fitting that prevents the groove of the armature 11 and the square portion of the yoke piece 5 from coming out of engagement.

The valve 25 is swingably attached to the valve fitting 13 so as to face the valve seat 26 .

Effects of Examples Next, the operation will be explained.

In the state shown in FIG. 2, when the excitation coil 3 is not energized, the valve 25 is pressed against the valve seat 26 shown by the phantom line due to the initial load of the return spring 15.

As the current of the excitation coil 3 is gradually increased, the magnetic attraction force is also gradually increased, and the valve 25 eventually floats above the valve seat 26.

Then, until the stopper 14 fixed to the armature 11 comes into contact with the iron core 1, the magnetic attraction force due to the current of the excitation coil 3 and the force of the return spring 15 are balanced, and the valve 25 operates proportionally and continuously. Change the opening proportionally and continuously.

The same applies to the case of reducing the current, and of course the opening degree of the valve can also be maintained at an arbitrary position.

Next, the reason why the present invention enables proportional operation while the conventional example is ON-OFF operation will be explained.

The first is to create a notch A in the magnetic pole part of the iron core 1 that is slightly inclined with respect to the armature 11, and the suction piece 12 fixed to the tip of the armature 11 generally operates inside the notch A. By doing this, it was possible to obtain flat static suction force characteristics with respect to the stroke as shown in FIG.

This point will be explained in more detail.

Figure 3 is a characteristic diagram of the conventional example, with solid line ■2. ■2゜■3 shows the static attraction force characteristics at each current (11<■2<13), and the broken line shows the relationship between the stroke of the return spring d and the force.

Point Sc on the horizontal axis is the valve closed position, point So is the valve fully open position, and point Pc on the vertical axis is the spring force, ie, the valve closing force, at point Sc on the horizontal axis.

In conventional open/close solenoid valves, the current 3 which always provides a larger magnetic attraction force than the force of the return spring 15 is turned on and off. Considering the operation when the current increases to 1, the valve remains stationary at a current of less than 11, at which an attractive force equal to the valve closing force Pc of the return spring d is obtained, but the valve starts floating from 1.

However, when the current is increased a little further and reaches ■2, the return spring d
The equilibrium point is lost, and the valve instantly moves to the fully open position So at a current that is greater than (2).

FIG. 4 is a characteristic diagram of one embodiment of the present invention, and the symbols in the diagram are the same as in FIG. 3.

As is clear from the figure, the attraction force characteristics in Figure 4 are extremely flat compared to Figure 3, and the current flows over the entire stroke from current 11, which produces the same attraction force as the valve closing force Pc, to current ■2, which fully opens the valve. It can be seen that ■1 (■1≦■1≦I2) equals the force of the spring.

The second point is that the fulcrum structure of the present invention is approximately a knife structure.

In the conventional example, since the operation is based on opening and closing magnetic attraction, press punching was sufficient for the fulcrum part, but since this configuration has sliding parts, if the current is gradually increased, it will be difficult to respond to minute changes in the current. do not follow.

In the present invention, a fulcrum structure that moves extremely smoothly in combination with the magnetic pole structure enables proportional operation.

An enlarged fulcrum sectional view of an embodiment of the present invention is shown in FIGS. 5 and 6.

In the case of a sharp knife structure as shown in Fig. 5, the armature 11 operates very smoothly at the beginning of operation, but when durability is important, the edge has a small pressure receiving area and the fulcrum, which is prone to wear, wears out. Then, the set pressure of the return spring 15 changes, and the characteristics change accordingly.

Therefore, as shown in Figure 6, by providing a minute R with a radius of about 0.1 mm to 0.6 mm at the tip of the edge, we can create an electromagnetic proportional valve with excellent durability without impairing the smoothness of proportional operation. made possible.

If this R is too large, frictional resistance will increase and smooth proportional operation will be impaired.

In addition, the penetrating portion of the base 2 between the iron core 1, which has a circular cross section, and the yoke rod 4 can be easily sealed with an O-ring.

In this embodiment, since the return spring 15 can be adjusted from the outside, this part is sealed using a blind lid 19, but in a device that does not have this adjustment function, such a seal is not required. No configuration required.

Effects of the Invention (1) While maintaining the advantage of miniaturization of the swing type solenoid valve, the flow rate can be controlled continuously and proportionally by controlling the energization of the excitation coil.

(2) Since the excitation coil is installed outside the fluid passage,
It is highly safe against flammable fluids, and since it does not use a flexible seal membrane, it is highly reliable for long-term use.

(3) Since both the iron core and the magnetic pole part have a circular cross section and pass through the base, this part can be sealed using an O-ring, making the sealing easy and reliable.

(4) Since the fulcrum support part of the armature has a moon shape and a V-shaped groove, it is effective in smooth proportional control without causing sliding.

(5) Since the iron core itself is provided through the base, the magnetic efficiency is improved compared to the case where yoke plates are provided at both ends of the iron core.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional 0N-OFF type solenoid valve, Figure 2
The figure is a sectional view of a valve device showing an embodiment of the present invention, Figure 3 is a characteristic diagram of a conventional example, Figure 4 is a characteristic diagram of the present invention, and Figures 5 and 6 are an embodiment of the present invention. It is a partial sectional view of the fulcrum part showing. 1... Iron core, 2... Base, 3... Excitation coil, 4...
Yoke rod, 5... Yoke piece, 7... Yoke plate, 11... Armature, 12... Suction piece, 15... Return spring, 25... Valve, A
...notch part.

Claims (1)

[Claims] 1. An iron core with a circular cross section is provided at the center of the excitation coil, and the cut-out magnetic pole end of the iron core is passed through the base, and this penetrating portion is sealed with an O-ring, the other end is fixed to a yoke plate, and the other end is fixed to the yoke plate. A yoke frame with a circular cross section is fixedly connected, the other end of the yoke frame passes through the base, this penetrating part is sealed with an O-ring, a yoke piece is fixed to the tip, and the end of the yoke piece is made into a substantially rectangular shape. A valve is provided at one end of the armature, a return spring is hooked at the other end, and the end of the armature on the iron core side is engaged with a substantially V-shaped groove of the armature to form a fulcrum support part. The notched magnetic pole portion is configured to swing approximately within the notched magnetic pole portion of the iron core, and the notched magnetic pole portion has an inclined surface such that a gap between the two is narrowed when the armature is attracted and rotated. Electromagnetic proportional valve.