JP2006266634A - Solenoid expansion valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid expansion valve capable of controlling a refrigerant for use in an air-conditioning and heating cycle with high accuracy and high responsiveness. <P>SOLUTION: The solenoid expansion valve 1 comprises a valve body 10 having a first passage 11 and a second passage 12, and a sub-body 20 inserted in the valve body 10. The sub-body 20 has a valve seat part 23 having a valve opening 22, and a valve stem 50 is inserted in a guide member 40. A refrigerant in the second passage 12 acts upon both ends of the valve stem 50 having a valve part 52, through by-pass passages 18, 25. A housing 100 fitted to the valve body 10 has a can 110 to which a suction element 120 is fitted. A plunger 150 operates the valve stem 50 integrally with a push rod 130. Valve opening is controlled by changing a current applied to an electromagnetic coil 200. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an expansion valve that is incorporated in a refrigeration cycle and controls the flow rate of a refrigerant, and relates to an electromagnetic expansion valve of a type in which a valve opening / closing operation is performed by an electromagnetic solenoid device.

The electromagnetic expansion valve controls the valve opening degree by operating the valve according to the magnitude of the current applied to the electromagnetic coil.
This type of electromagnetic expansion valve is disclosed in, for example, the following patent document.
JP 2003-4341 A

In this type of electromagnetic expansion valve, when controlling a high-pressure refrigerant, there is a problem that it is difficult to control the flow rate finely and accurately, or that the response is insufficient.
An object of the present invention is to provide an electromagnetic expansion valve that solves the above-described problems.

In order to achieve the above object, in the electromagnetic expansion valve of the present invention, the valve body is provided with a first passage and a second passage through which a refrigerant passes, and the valve body includes the first passage and the first passage. An electromagnetic solenoid device comprising a sub-body having a valve seat having a valve opening communicating with the second passage, and opening and closing a valve rod having a valve portion for opening and closing the valve opening with respect to the valve opening. The valve body is equipped with a two-stage characteristic in which a valve opening characteristic of the valve portion with respect to the valve opening is small in a low opening region and large in a high opening region exceeding the low opening region. To do.
In order to have the two-stage valve opening characteristic, the valve portion specifically includes a first taper portion and a flat portion from the narrowest end portion of the first taper portion toward the center of the valve stem or the first portion. A second taper portion having a second taper angle larger than the first taper angle of the taper portion is provided.
More preferably, the valve main body or the sub-main body is provided with a bypass passage that causes the refrigerant pressure of the second passage to act on both ends of the valve stem so as to cancel the force due to the refrigerant pressure acting on the valve stem. .
More preferably, the diameter of the valve stem has the same diameter as the valve opening.
By adopting such a configuration, the flow direction of the refrigerant can be applied in either the forward or reverse direction.
At this time, it is preferable that the second passage includes an orifice member having an opening area which is equal to or slightly smaller than the maximum opening area of the valve seat.

  The electromagnetic expansion valve of the present invention having the above-described configuration can finely and accurately control the flow rate of the high-pressure refrigerant with good responsiveness. Moreover, the flow of the refrigerant is reversible and can be used for both cooling and heating.

As shown in FIGS. 1 and 2, the electromagnetic expansion valve generally indicated by reference numeral 1 includes a valve body 10 having a first passage 11, a second passage 12, and a bypass passage 18. Bypass passage 18 leads to the refrigerant pressure in the second passage to the chamber H ₁ exposing the valve stem 50 will be described later.
A central part 20 of this valve body 10 is further provided with a sub-main body 20 having a valve chamber 21.
The sub-main body 20 has a valve seat portion 23 having a valve opening 22, and the valve chamber 21 above the valve seat portion 23 communicates with the first passage 11 of the valve main body 10, and below the valve seat portion 23. The chamber 24 communicates with the second passage 12 of the valve body 10.
When the refrigerant flows from the first passage 11 through the valve opening 22 of the valve seat portion 23 to the second passage 12 side, the orifice member 30 further reduces the refrigerant flow rate immediately after throttling by the valve seat portion, The pressure balance is maintained and a stable control is obtained.

The sub-main body 20 has a bypass passage 25 that opens to the second passage 12 side, and sends the refrigerant to the chamber H ₂ side formed between the valve main body 10 and the lid member 90.
A guide member 40 is disposed on the upper portion of the sub-main body 20 to guide the valve stem 50 in a slidable manner.

The valve stem 50 has a valve portion 52 and is connected to a tip guide portion 54 of the valve stem through a small diameter portion 56 that passes through the valve opening 22. The tip guide 54 of the valve stem is supported by a sleeve 60 that is press-fitted and fixed to the sub-main body 10. The tip guide portion 54 of the valve stem 50 is supported by a spring receiving member 70. The spring receiving member 70 is supported by a screw member 80 for adjustment via a coil spring 72. Screw member 80 is screwed through the threaded portion N ₂ to an internal thread of the sub-main body 20. By adjusting the screwing amount of the screw member 80, the spring force of the coil spring 72 can be adjusted. The screw member 80 is formed with a lateral groove 82 for receiving a tool and a through hole 84, and the refrigerant on the chamber H ₂ side is passed through the through hole 84 into the chamber H ₃ facing the tip guide portion 54 of the valve rod. Introduce.

The lid member 90 is screwed into the screw portion N _1, seals the opening of the valve body 10. An O-ring 92 is interposed to complete the seal.
The top of the valve body 10 has a threaded portion N _3, the housing 100 of the electromagnetic solenoid device is screwed. A can 110 made of a nonmagnetic material is press-fitted into the housing 100, and the attractor 120 is fixed inside the can 110.

In the can 110, the plunger 150 is slidably inserted on the upper part of the suction element 120. A push rod 130 penetrating through the center hole of the suction element 120 is press-fitted into the plunger 150, and the push rod 130 and the plunger 150 are integrated.
A coil spring 152 is mounted on the top of the plunger 150. The coil spring 152 has a weaker spring force than the coil spring 72 and has a function of bringing the push rod 130 into contact with the valve rod 50.

  The push rod 130 is slidably guided by sleeves 140 and 142 that are press-fitted into the suction element 120. The sleeves 140 and 142 are plated to reduce sliding resistance.

An electromagnetic coil 200 wound around a bobbin 210 is provided on the outer periphery of the can 110. The electromagnetic coil 200 draws the plunger 150 toward the attractor 120 side (downward) by being fed from a lead wire (not shown).
The upper part of the electromagnetic coil 200 is sealed with a plate 160.

Here, the specific shape of the valve portion 52 in the electromagnetic expansion valve of the present invention will be described in comparison with a conventional configuration.
In the conventional valve shown in FIG. 7, it has a tapered portion 52 'of the first stage facing the valve seat (valve aperture), the valve opening characteristics, as shown in the curve C ₃ in FIG. 5, the valve stem The opening area of the valve changes substantially linearly with the amount of movement. However, in the electromagnetic expansion valve of the present invention exhibits a valve opening characteristic of the two-stage characteristics shown in curve C ₂ in FIG. That is, a small opening characteristic (gradual gradient) is exhibited in the low opening region, and a larger opening characteristic (steep gradient) is exhibited in the high opening region.

An example of the specific shape of the valve portion 52 for exhibiting such an opening characteristic of a two-stage characteristic will be described with reference to FIG.
The valve portion 52 provided in the valve stem 50 of the present invention has a first tapered portion 52 a that can enter the valve opening 22 of the valve seat portion 23. The first tapered portion 52a has a small inclination angle with respect to the inner peripheral surface of the valve opening 22, and fully closes the edge of the valve opening 22 when the first taper portion 52a enters the deepest. In this embodiment, a flat portion 52b is formed from the most detailed portion of the tapered portion 52a toward the center line of the valve stem. The flat portion 52b may be a second tapered portion having a large inclination angle in a range that exhibits the two-stage opening characteristics of FIG.
A flange portion 52c is formed to bulge at the upper portion of the first taper portion 52a, and the deepest penetration depth of the first taper portion 52a with respect to the valve opening 22 is regulated.

4A to 4E show the change characteristics of the valve opening area F ₁ corresponding to the change of the lift L ₁ of the valve stem 50 in FIG.
FIG. 3 and FIG. 4 (a) show the closed state, and the opening area is zero. In the regions (b) to (c), the first tapered portion 52a of the two-stage valve slightly changes the opening area with respect to the valve opening 22. In the this area (small opening area), as shown in FIG. 4, the opening area to the valve lift L ₁ is gradually increased in the small rate of change.
The boundary between the tapered portion 52a and the flat portion 52b of the two-stage valve shown in (c) of the figure is shown in (d) of the figure from the position (c) aligned with the horizontal position of the valve opening 22 (the upper surface of the valve seat 23). When the valve stem 50 is further lifted toward the position, the opening area of the valve increases with a large rate of change. (E) of a figure shows the valve fully open state. Even if the valve rod 50 is lifted more than the state (e), the valve opening degree is maintained at the maximum value.

In the electromagnetic expansion valve comprising a two-stage opening characteristic which is a feature of the present invention, as shown in FIG. 5, the control current E, varying the opening area of the valve as indicated by the curve C ₂ Can do.
That is, the control when the conventional curve C ₃ the width of the control current E ₂ in the stationary control zone K ₂ for controlling the valve opening area between the valve opening 22 of the tapered portion 52a and the valve seat portion 23 of the valve portion 52 it can be increased as compared with the current E _3. Therefore, control with higher resolution can be achieved.
In the cool-down region K ₁ (rapid cooling) in which the valve opening area rapidly increases and a large amount of refrigerant flows, high-speed response control can be performed with a smaller control current width.

In order to perform the valve opening control as described above accurately and with good responsiveness, the present invention is devised to eliminate or reduce the influence of the refrigerant pressure difference acting on the valve stem 50.
That is, as shown in FIG. 2, the valve diameter D ₁ , the outer diameter D _{2 of the} valve stem 50 guided by the guide member 60, and the outer diameter D ₃ of the valve stem tip guide portion 54 are:
D ₁ = D ₂ = D ₃
It is set to the relationship.
The high-pressure refrigerant (PH) supplied to the first passage 11 side is throttled and depressurized (PL) by the valve opening 52 of the valve portion 52 and the valve seat portion 23, and then the small-diameter portion 56 of the valve stem 50 and the valve opening 22. sent to the top of the chamber H ₁ of the valve stem 50 through the bypass passage 18 with acting between and chamber bypass passage 25 of the sub-main body 20, the tip guide portion 54 of the valve stem through the chamber H ₂ is located also sent to H _3.

The effect | action with respect to each part of the valve stem 50 of these refrigerant | coolant pressures is demonstrated referring FIG. 6 which shows typically. FIG. 6A shows a normal flow (cooling operation) state, and FIG. 6B shows a reverse flow (heating operation) state.
In the positive flow of FIG. 6A, the valve rod 50 is formed with a flange portion 52c on which the high-pressure refrigerant PH in the first passage 11 acts, so that when the refrigerant having the pressure PH is introduced into the passage 14, the valve Pressure PH acts on the upper and lower portions of the flange portion 52c of the rod 50, which is indicated by 1 and surrounded by a circle, and the force acting on the valve rod 50 is canceled out.
^{_{(ΠD 4 2/4-πD}} 1 2/4) × PH = (πD 4 2/4-πD 1 2/4) × PH
Here, _{D 4} is the outer diameter of the flange portion 52c.
Further, the pressure PL that has been reduced in pressure after passing through the throttle portion by the valve portion 52 and the valve opening 22 acts on a portion indicated by 2 surrounded by a circle. In the portion indicated by circled 2, the force acting in the upward direction ^{_{(πD 1 2/4-πD}} 5 2/4) × PL
It is.
Force acting downwards ^{_{(πD 3 2/4-πD}} 5 2/4) × PL
It is. Here, since D ₁ = D ₃ , the force acting on the portion indicated by 2 surrounded by a circle is also canceled out.
Further, on the second passage 12 side, it communicates with the chamber H ₁ above the valve stem 50 and the chamber H ₃ of the valve stem guide 54 via the bypass passage 18 and the bypass passage 25 (see FIG. 1). Therefore, even the chamber _{H 1} and the chamber _{H 3} refrigerant of the low pressure PL of the second passage 12 side acts. Therefore, in the portion indicated by 3 at the upper and lower ends of the valve stem 50, the upper part of the valve is directed downward.
^{_{(ΠD 2 2/4) ×}} PH
The force of
On the bottom of the valve,
^{_{(ΠD 3 2/4) ×}} PH
The force of acts. Since D ₂ = D ₃ here, the force acting on the circled portion 3 is also canceled out.
That is, all the loads due to the refrigerant pressure acting around the valve stem 50 are offset. Therefore, since the valve stem 50 is controlled by the balance between the attractive force generated by the electromagnetic coil 200 and the spring 72 without being affected by the refrigerant pressure, an accurate flow rate can be obtained by varying the applied current to the electromagnetic coil 200. Control can be performed.

  In this positive flow refrigeration cycle, as described above, since the load due to the refrigerant pressure acting on the valve stem 50 is canceled, the valve opening is controlled by appropriately controlling the current value applied to the electromagnetic coil 200. It can be controlled accurately.

FIG. 6B shows a so-called reverse flow cycle in which the high-pressure refrigerant PH that has passed through the evaporator flows into the passage 12 side. In this cycle, a heating operation is performed in which high-temperature and high-pressure refrigerant passes through an evaporator (heat exchanger).
Upward in the portion indicated by circled ^{_{2 (πD 1 2/4-}} πD 5 2/4) × PH
The force of
The downward ^{_{(πD 3 2/4-πD}} 5 2/4) × PH
The force of acts.
Since D ₁ = D ₃ here, the force acting on the portion indicated by 2 surrounded by a circle is canceled out.
Furthermore, communicates with the lower portion of the chamber of H ₂ the upper part of the chamber H ₁ and the valve rod guide portion 54 of the valve stem 50 through the bypass passage in the passage 12 side. Therefore, the high-pressure PH refrigerant on the passage 12 side acts on the chambers H1 and H2.
In the part indicated by circles 3 that are the upper and lower ends of the valve stem 50, the valve upper part is directed downward,
^{_{(ΠD 2 2/4) ×}} PH
The force of
On the bottom of the valve,
^{_{(ΠD 3 2/4) ×}} PH
The force of acts. Since D ₂ = D ₃ here, the force acting on the portion indicated by 3 surrounded by a circle is also canceled out.
The pressure PL that has passed through the throttle portion formed by the valve portion 52 and the valve seat 42 and reduced in pressure acts above and below the circled portion 1 of the flange portion 52c of the valve stem 50, and this force is canceled out. .
^{_{(ΠD 4 2/4-πD}} 1 2/4) × PL = (πD 4 2/4-πD 1 2/4) × PL
Even in this reverse flow, all the loads due to the pressure acting on the valve stem 50 are balanced, so that the flow rate can be accurately controlled without being influenced by the pressure by controlling the current value flowing through the electromagnetic coil 200.
Thus, the electromagnetic expansion valve of the present invention can provide a heat pump type air conditioning system capable of accurate control in either forward or reverse flow.

In the above-described embodiment, the example in which the load due to the fluid pressure acting on the valve stem 50 is almost completely canceled has been described. However, the dimensions D ₁ , D ₂ , and D ₃ should be appropriately selected. Therefore, it is possible to intentionally apply a force in the opening direction or the closing direction to the valve stem 50, and it is possible to appropriately tune the operation of the valve according to the purpose of use or the purpose of control.

The center longitudinal cross-sectional view of the electromagnetic expansion valve of this invention. The principal part enlarged view of the electromagnetic expansion valve of this invention. Explanatory drawing which shows the structure and effect | action of a valve part in the electromagnetic expansion valve of this invention. Explanatory drawing which shows the relationship between the valve lift and opening area of the electromagnetic expansion valve of this invention. Explanatory drawing which shows the relationship between the control current and opening area of the electromagnetic expansion valve of this invention. Explanatory drawing which shows typically the effect | action of the pressure balance in the electromagnetic expansion valve of this invention. Explanatory drawing of the conventional valve part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electromagnetic expansion valve 10 Valve main body 11 1st channel | path 12 2nd channel | path 18 Bypass channel | path 20 Sub-main body 21 Valve chamber 22 Valve opening 23 Valve seat part 24 Chamber 25 Bypass channel | path 30 Orifice member 40 Guide member 50 Valve rod 52 Valve part 52a First taper portion 52b Flat portion 52c Flange portion 60 Sleeve 70 Spring receiving member 80 Screw member 90 Lid member 100 Housing 110 Can 120 Aspirator 130 Push rod 140, 142 Sleeve 150 Plunger 200 Electromagnetic coil

Claims (8)

The valve body is provided with a first passage and a second passage through which the refrigerant passes,
The valve main body includes a sub main body including a valve seat having a valve opening communicating between the first passage and the second passage;
An electromagnetic solenoid device that opens and closes a valve stem having a valve portion for opening and closing the valve opening with respect to the valve opening is equipped in the valve body,
The electromagnetic expansion valve according to claim 1, wherein the valve opening characteristic of the valve portion with respect to the valve opening has a two-stage characteristic that is small in a low opening region and large in a high opening region that exceeds the low opening region.   2. The valve portion according to claim 1, wherein the valve portion has a first taper portion and a flat portion from the thinnest end portion of the first taper portion toward the center of the valve stem, or the first portion so as to have the two-stage valve opening characteristic. An electromagnetic expansion valve comprising a second taper portion having a second taper angle larger than the first taper angle of the taper portion.   3. The bypass according to claim 1, wherein the valve body or the sub-body has a refrigerant pressure in the second passage acting on both ends of the valve rod so as to cancel a force caused by a refrigerant pressure acting on the valve rod. An electromagnetic expansion valve comprising a passage.   4. The electromagnetic expansion valve according to claim 3, wherein the diameter of the valve stem has the same diameter as the valve opening.   The electromagnetic expansion valve according to any one of claims 1 to 4, wherein the flow direction of the refrigerant can be applied in both forward and reverse directions.   6. The electromagnetic expansion valve according to claim 5, wherein the second passage includes an orifice member having an opening area that is equal to or slightly smaller than a maximum opening area of the valve seat.   2. The electromagnetic solenoid device according to claim 1, wherein the electromagnetic solenoid device includes a movable plunger to which a push rod for operating the valve rod is fixed, a fixed suction element facing the plunger, and the plunger and the suction element. And an electromagnetic coil disposed on the outer periphery of the can.   8. The electromagnetic wave according to claim 7, wherein the suction element is positioned on the valve body side, the plunger is positioned outward of the suction element, and the push rod penetrates the suction element slidably. Expansion valve.

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