JPH0141870B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a pressure proportional control valve that can arbitrarily control the pressure on the fluid outlet side using electromagnetic force generated in response to an electric signal. Structure of a conventional example and its problems FIG. 1 shows the structure of a conventional pressure proportional control valve of this type. In FIG. 1, reference numeral 1 indicates a governor section for controlling pressure, and reference numeral 2 indicates a drive section for generating electromagnetic force for controlling pressure. The governor section 1 includes a fluid inlet 3 and a fluid outlet 4, a valve seat 5 provided between the fluid inlet 3 and the fluid outlet 4, and a valve seat 5.
A diaphragm 7 supported by the valve body 6 and operated in response to the pressure (hereinafter referred to as primary pressure) P ₁ on the fluid inlet 3 side urges the valve body 6 in the valve closing direction. It is comprised of an elastic body 8 and a stopper 9 that restricts the amount of displacement of the valve body 6. The drive unit 2 includes a coil 1 wound around a bobbin 10.
1. Yoke 1 provided to surround coil 11
2. A sliding tube 13 provided through the center of the coil 11, and a plunger 1 provided inside the sliding tube 13.
4. Mounting base 1 forming a back pressure chamber for the diaphragm 7
It consists of 5. When the coil 11 is energized, an electromagnetic force Fm corresponding to the amount of energization acts on the valve body 6, the valve body 6 is displaced downward, and the fluid flows out to the fluid outlet 4 side, creating a secondary pressure of _P2 . arise. In such a power relationship,
If the pressure-receiving areas of the valve body 6 and the diaphragm ₇ are set equal, changes in the primary pressure P1 will be canceled, and the balance between the force that lifts the valve body 6 upward by the secondary pressure _P2 and the electromagnetic force Fm will cause the valve to change. The opening degree is determined. In other words, a secondary pressure _P2 corresponding to the electromagnetic force Fm can be obtained, and it also has a well-known governor function. Therefore, by controlling the amount of current applied to the coil 11, the secondary pressure _P2 can be arbitrarily controlled. However, in the conventional example, the electromagnetic force Fm changes with the displacement of the valve body 6, that is, the displacement of the plunger 14, even though the same magnetomotive force is applied, so an overshoot phenomenon occurs in the governor characteristics. This point will be explained in detail based on FIGS. 2 and 3. FIG. 2 is a characteristic diagram showing the relationship between the displacement amount X of the valve body 6 (the displacement amount of the plunger 10) and the electromagnetic force Fm when a predetermined magnetomotive force, that is, the amount of current applied to the coil 11 is applied, and FIG. indicates the governor characteristics. Here, when trying to obtain the desired secondary pressure P ₂ m by energizing the coil 11, the valve body 6 with the characteristics shown in FIG.
The amount of displacement is from the closing point Xo to Xa and is balanced with the electromagnetic force Fa. However, the primary pressure P ₁ at this time is the standard pressure P ₁ a. When designing the governor section 1, the distance at which the valve body ₆ contacts the stopper ₉ , that is, the maximum displacement, is determined so that the desired secondary pressure _P2m can be obtained even when the primary pressure P1 reaches the minimum pressure P1 min. The amount Xmax is designed to be an optimal value so as to have a margin and take ozone deterioration of the diaphragm 7 into consideration so that large stress is not applied. In this state, when the primary pressure P ₁ changes to the maximum pressure P ₁ max, the valve body 6 moves in the valve closing direction.
The displacement reaches Xb, and the secondary pressure P ₂ m is maintained. Next, when the primary pressure P ₁ reaches the minimum pressure P ₁ min, the secondary pressure P ₂ m decreases, so the valve body 6 is displaced downward and the valve opening increases, maintaining the secondary pressure P ₂ m. It works like that. At this time, the valve body 6 comes into contact with the stopper 9, and the amount of displacement of the valve body is
Xmax, and the electromagnetic force becomes Fmax. Therefore, when the primary pressure P ₁ further increases from the lowest pressure P ₁ min, it is larger by ΔFm ₁ than the set electromagnetic force Fa.
The valve body 6 is displaced upward only when the secondary pressure P ₂ m' balances with Fmax. Therefore, an overshoot of ΔP ₂ m occurs, and the desired secondary pressure P ₂ m cannot be obtained. In particular, when controlling the pressure (flow rate) of the fuel gas, the amount of combustion increases and there is a risk of damaging a heat exchanger or the like (not shown). For this reason, in the conventional example, the shape of the plunger 14 is made complicated, the magnetic gap is made large, the magnetic efficiency is reduced, and the electromagnetic force change ΔFm ₂ is reduced as shown in FIG. As a result, it was inevitable that the coil 11 would become larger and its power consumption would increase. Purpose of the Invention In view of the above-mentioned conventional problems, the present invention solves the overshoot of the governor characteristics by selecting the mutual positional relationship between the operating range of the plunger and the amount of displacement of the valve body, and also reduces the size of the drive unit. The purpose is to make it more compact. Structure of the Invention In order to achieve this object, the pressure proportional control valve according to the present invention includes: a valve seat provided in a fluid passage; a governor portion having a valve body provided opposite to the valve seat and supported by a diaphragm; Consisting of a coil, a yoke, and a drive unit having a plunger that moves on the central axis of the coil and applies electromagnetic force to the valve body,
The maximum displacement of the valve body is Xmax, and the axial gap between the upper end surface of the yoke and the upper end surface of the plunger is gPu.
The axial gap between the lower end surface of the yoke and the lower end surface of the plunger is gPd, and when the valve is closed, Xmax≧
gPd＞(Xmax−1), gPu＞(Xmax−1)(mm)
It is designed to satisfy the following conditions. With this configuration, changes in electromagnetic force due to displacement of the plunger can be reduced without reducing magnetic efficiency, thereby eliminating overshoot in governor characteristics and making it possible to downsize the drive unit. DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings. FIG. 4 shows a structural diagram of the pressure proportional control valve according to the present invention.
Xmax, the gap in the axial direction between the upper end surface 12u of the yoke 12 and the upper end surface 14u of the plunger 14 is gPu, the lower end surface 12d of the yoke 12 and the lower end surface 1 of the plunger 14;
When the gap in the axial direction of 4d is gPd, the relative positions thereof at the valve closing point, that is, the state in which the valve body 6 is in contact with the valve seat 5, are configured so as to satisfy the following condition. (1) Xmax≧gPd>(Xmax-1)(mm) (2) gPu>(Xmax-1)(mm) The rest is the same as the conventional example shown in FIG. 1, so the same symbols are given and the explanation is omitted. FIG. 5 is a cross-sectional view of the main part of FIG. 4, showing the amount of displacement of the plunger 14 (the amount of displacement of the valve body 6) and
It shows the change in electromagnetic force Fm when the amount of current applied to is constant. When the plunger 14 descends from the valve closing point Xo, the gap gPd formed between the lower end surface 12d of the yoke 12 and the lower end surface 14d of the plunger 14, that is, the magnetic gap, becomes smaller and the plunger 14
The power to attract increases. However, the lower end surface 12d of the yoke 12 and the lower end surface 14d of the plunger 14
A component that lifts the plunger 14 upwards acts with a peak point near the point where the gap gPd becomes 0, and the electromagnetic force Fm starts to decrease and the plunger 14 reaches its peak at the point Xmax where the valve body 6 comes into contact with the stopper 9. 14 stops. Figure 6c is a characteristic diagram showing the relationship between the displacement position X of the valve body 6 and the electromagnetic force Fm _.
It is made to be approximately equal to the electromagnetic force Fa at the valve opening Xa at P ₁ a. FIG. 7E shows the governor characteristics according to this example,
As shown in Fig. 6c, the valve body 6 is at the maximum displacement position Xmax.
Since the _difference in electromagnetic force is ΔFm when the displacement _is up _to
When the secondary pressure becomes approximately equal to , the valve body 6 is displaced upward and approaches the valve opening Xa at the standard pressure P ₁ a. Therefore, no overshoot phenomenon occurs. Note that if gPd>(Xmax−1) does not hold,
In other words, when the valve body 6 reaches the maximum displacement Xmax, the plunger lower end surface 14d changes to the yoke lower end surface 12d.
If it is located 1mm or more below, and gPu>
If (Xmax−1) does not hold, that is, when the maximum displacement amount Xmax is reached, the plunger upper end surface 14u
In any case where the plunger 14 is located 1 mm or more below the yoke upper end surface 12u, a force that lifts the plunger 14 upward acts, and the electromagnetic force Fm suddenly decreases as shown in FIG. 6D. Therefore, as shown in FIG. 7F, the valve body 6 is displaced upward before the secondary pressure P ₂ m is reached, and a difference in ΔP ₂ occurs, resulting in a reduction in performance. As described above, according to this embodiment, the displacement amount Xmax of the valve body 6 and the mutual positional relationship between the plunger 14 and the yoke 12 are optimized, so that it is possible to eliminate the occurrence of overshoot in the governor characteristics.
Further, since it can be configured under conditions where the change constant of the electromagnetic force Fm with respect to the displacement of the plunger 14 is large, that is, under conditions where magnetic efficiency is high, it is possible to drive with a small magnetomotive force, and the drive unit 2 can be made smaller and more compact. Table 1 shows the valve seat diameter = 36 and the same secondary pressure P ₂
(240mmH ₂ O) Comparing the conventional pressure proportional control valve and the one of the present invention, the magnetomotive force is reduced by approximately 20%, and the coil weight is approximately halved, resulting in smaller size and lower cost. We were able to realize this.

[Table] Effects of the Invention As described in detail above, the pressure proportional control according to the present invention establishes the mutual positional relationship between the operating range of the plunger with respect to the yoke and the displacement amount of the valve body such that in the valve closed state, Xmax≧gPd> (Xmax−1),
It is configured to satisfy the condition gPu > (Xmax-1) (mm), and the change in electromagnetic force with respect to the displacement of the valve body is parabolic, so that the electromagnetic force and valve body in steady state reach the maximum displacement. Since the electromagnetic forces can be made approximately equal when reaching the position, overshoot of the governor characteristics does not occur. Furthermore, since the drive section can be configured under conditions with high magnetic efficiency, it can be driven with less magnetomotive force, resulting in smaller coils and lower costs. Furthermore, since there is no need to reduce the change constant of the electromagnetic force with respect to the displacement of the valve body, there is no need for special considerations such as the shape of the plunger and the shape and size variations of the part that becomes the magnetic gap in the magnetic circuit, resulting in a simple structure. Processing and assembling properties are also improved.

[Brief explanation of drawings]

Figure 1 is a cross-sectional structural diagram of a conventional pressure proportional control valve.
FIG. 2 is an electromagnetic force characteristic diagram, FIG. 3 is a governor characteristic diagram, FIG. 4 is a sectional structural diagram of a pressure proportional control valve showing an embodiment of the present invention, and FIG. 5 is a sectional diagram of the same essential parts. 6th
The figure shows the electromagnetic force characteristic diagram, and FIG. 7 shows the same governor characteristic diagram. 1... Governor part, 2... Drive part, 5... Valve seat,
6...Valve body, 7...Diaphragm, 11...Coil, 12...Yoke, 12u...Yoke upper end surface, 12d...Yoke lower end surface, 14...Plunger, 14u...Plunger upper end surface, 14d...
Lower end of plunger.

Claims (1)

[Claims] 1. A valve seat provided in a fluid passage, a valve body provided opposite to the valve seat, a governor portion having a diaphragm provided integrally with the valve body, a coil, and a governor portion provided so as to surround the coil. a yoke provided so as to surround the coil, and a drive section composed of a plunger that moves on the central axis of the coil and applies an electromagnetic force to the valve body. The maximum displacement is X _nax , and the axial gap between the upper end surface of the yoke and the upper end surface of the plunger is
gpu, the axial gap between the lower end surface of the yoke and the lower end surface of the plunger is gpd, and when the valve body is in contact with the valve seat, X _nax ≧gpd> (X _nax −1),
A pressure proportional control valve configured to satisfy the condition: gpu > (X _nax -1) (mm).