JP5743744B2 - Diaphragm type fluid control valve - Google Patents

Description

  The present invention relates to a diaphragm type fluid control valve having a valve element driving diaphragm for adjusting the flow rate or pressure of a fluid, and more particularly, a diaphragm type suitable as an expansion valve used in a heat pump type air conditioning system such as a car air conditioner. The present invention relates to a fluid control valve.

  As an expansion valve used in a heat pump type air conditioning system, a valve body for adjusting the flow rate or pressure of a fluid (refrigerant), an inlet and an outlet are provided, as can be seen in Patent Document 1 below. There is known a diaphragm type fluid control valve comprising a valve body formed with a valve opening (orifice) that is opened and closed by the valve body and a diaphragm device that drives the valve body in the valve opening / closing direction. Yes.

  In this diaphragm type fluid control valve, the diaphragm device is usually sealed and fixed so as to sandwich the diaphragm and the outer peripheral portion of the diaphragm, and the upper surface side pressure chamber of the diaphragm which is a sealed space (the temperature sensitive chamber). A diaphragm holding member that defines a diaphragm chamber), and a lower surface of the diaphragm has an operating rod through a stopper to transmit displacement (deflection) of the diaphragm to the valve body. Are connected.

  A predetermined gas (for example, R134a) is usually sealed in the pressure chamber (sensing greenhouse) at a predetermined pressure.

  In addition, the diaphragm has an upward convex or downward convex peak when viewed in cross section between an outer peripheral portion sealed and fixed by the diaphragm holding member and an inner peripheral portion where the large-diameter disk-shaped portion abuts. A mountain-shaped portion having a concentric annular shape in plan view having N pieces [N is a positive integer (1, 2, 3,...)] Is formed.

  In the diaphragm type fluid control valve having such a configuration, the diaphragm (the inner peripheral portion of which is relative to the outer peripheral portion) usually has a pressure in the pressure chamber (sensitive room) (hereinafter referred to as a diaphragm upper surface side pressure) and a diaphragm. It is displaced up and down (deflection) according to the pressure difference with the pressure acting on the lower surface (hereinafter referred to as the diaphragm lower surface pressure), and this displacement is transmitted to the valve body via the stopper and the operating rod. The valve opening (= lift amount = effective opening area of the valve port) is adjusted by moving in the opening and closing direction (vertical direction), and this controls the pressure (flow rate) of the fluid (refrigerant) from the inlet to the outlet. It has come to be.

  The conventional diaphragm type fluid control valve as described above has the following problems to be solved.

  In other words, when the cross section is formed between the inner periphery and the outer periphery of the diaphragm, a convex peak is formed upward or downward, so that it is displaced in a vertical direction from a flat diaphragm without a peak. However, in the region where the differential pressure between the upper surface side pressure and the lower surface side pressure of the diaphragm is small (very low temperature region), the change in the lift amount is insufficient with respect to the change in the differential pressure. The flow rate did not change so much, and there was a problem that it was difficult to ensure the required flow rate and to perform stable flow rate control.

  Further, when the diaphragm diameter is reduced for the purpose of reducing the material cost of parts, the change in the lift amount is similarly reduced, and there is a problem that stable flow rate control becomes difficult.

  In order to change the lift amount greatly in response to changes in the differential pressure, measures such as reducing the diaphragm thickness and increasing the diaphragm diameter can be considered. However, if the diaphragm thickness is reduced, the strength is insufficient. In addition, there is a problem in that it is easily broken and the durability is lowered, and there is also a dislike that the diaphragm is easily bent and the stability of the flow rate control is lowered. In addition, when the diaphragm diameter is increased, the entire control valve is also increased, and it may be difficult to dispose it at a place where it should be disposed.

  Therefore, as described in Patent Document 2, the applicant of the present invention first protrudes upward or downward as viewed in cross section between the outer peripheral portion and the inner peripheral portion of the diaphragm that drives the valve body. A wave-like portion having a concentric ring shape in a plan view having convex peaks and [N + (0.25 to 0.75)], where N is a positive integer (1, 2, 3,...) Is formed. A diaphragm type fluid control valve is proposed.

  Hereinafter, an example of the proposed diaphragm type fluid control valve will be described with reference to FIG. FIG. 3 shows a diaphragm type fluid control valve 5 having a diaphragm having the above-described configuration. This diaphragm type fluid control valve 5 is omitted in FIG. 3 (see FIG. 6 of Patent Document 2). In addition to the valve body for adjusting the flow rate or pressure of the fluid, and the valve body provided with an inlet and an outlet and a valve opening opened and closed by the valve body between them, A diaphragm device 30G for driving the valve body in the valve opening / closing direction is provided.

  The diaphragm device 30G seals and fixes a diaphragm 35 (described in detail later) and an outer peripheral portion of the diaphragm 35, and defines an upper surface side pressure chamber 33 that is a sealed space on the upper surface side thereof. Holding member 32. FIG. 3 shows a neutral state (natural state) in which the diaphragm 35 is not displaced vertically.

  The upper surface side pressure chamber 33 is sealed with a plug 39 with a predetermined gas (for example, R134a) sealed therein with a predetermined pressure. A lower surface side pressure chamber 12 is formed on the lower surface side of the diaphragm 35.

  The diaphragm holding member 32 includes a central frustoconical portion 32c for defining the upper surface side pressure chamber 33, an annular flat plate portion 32d connected to the lower portion of the central frustoconical portion 32c and parallel to the neutral diaphragm 35, and A valve body for defining a substantially lid-like upper surface side pressure chamber defining portion 32A composed of an upper clamping portion 32e for sealing and fixing the outer peripheral portion of the diaphragm 35 and a part of the lower surface side pressure chamber 12 is provided. A cylindrical portion 32f in which a male screw portion 32i for attachment is formed, a bowl-shaped flat plate portion 32g connected to the cylindrical portion 32f and parallel to the neutral diaphragm 35, and a lower holding portion for holding the outer peripheral portion of the diaphragm 35 And a stepped cylindrical lower surface side pressure chamber defining part 32B comprising a part 32h.

  On the other hand, an operating rod 37 is connected to the lower surface side of the diaphragm 35 via a stopper 38 in order to transmit the displacement (deflection) of the diaphragm 35 to the valve body. The stopper 38 includes a short columnar portion 38a in which a fitting hole 38b in which the upper end portion of the operating rod 37 is fitted and fixed by press-fitting or the like is provided at the center thereof, and slightly below the upper end of the short columnar portion 38a. A large-diameter bowl-shaped disc portion 38c provided on the side, and an upper end surface 38d thereof is brought into contact with the inner peripheral portion (center portion) of the lower surface of the diaphragm 35.

  In addition, refrigerant (pressure) flowing through a flow passage (having a refrigerant inlet from the evaporator and a refrigerant outlet from the evaporator) formed in the valve body is introduced into the lower pressure chamber 12. The diaphragm 35 is displaced up and down (deflection) according to the pressure difference between the pressure in the upper surface side pressure chamber 33 and the pressure in the lower surface side pressure chamber 12, and this displacement is applied to the valve element via the operating rod 37. The valve body moves in the valve opening / closing direction (vertical direction) and the valve opening degree (= lift amount = effective opening area of the valve opening) is adjusted, whereby fluid (refrigerant) from the inlet to the outlet is adjusted. ) Pressure (flow rate) is controlled.

  In the illustrated example, the diaphragm 35 has a peak that is convex upward when viewed in cross section between the outer peripheral portion 35a sealed and fixed by the diaphragm holding member 32 and the inner peripheral portion 35c with which the upper end surface 38d of the stopper 38 abuts. Are formed in a mountain-shaped portion 35b having a concentric annular shape in a plan view having two halves (2.5).

  More specifically, the diaphragm 35 is made of a stainless steel plate (ASL350 or the like) having a thickness of about 0.10 mm, for example, and is formed into a disk shape. The second mountain M2 on the outer peripheral side is one mountain, but the third mountain M3 on the outermost outer periphery is 0.5 mountain, and in the natural state (neutral state) Using the upper surface of the peripheral portion 35c as a reference surface, the height difference (height of the mountain) from the reference surface to the peak is H (for example, 0.30 mm), and the height from the reference surface to the upper surface of the outer peripheral portion 35a. The difference is also the same H (for example, 0.30 mm).

  By the way, in general, in this type of diaphragm device, if the diaphragm is excessively displaced upward and downward, there is a possibility that the diaphragm may be deformed or damaged so as not to return to the original state. A stopper is provided for limiting the displacement. In the diaphragm device 30G of the illustrated example described above, the annular flat plate portion 32d is provided on the upper surface side pressure chamber defining portion 32A of the diaphragm holding member 32 so that the inner peripheral portion 35c of the diaphragm 35 is contacted and locked. The lower surface of the inner peripheral portion of the flat plate portion 32d serves as an upper stopper 51 for restricting excessive displacement of the diaphragm 35 upward, and as the lower stopper for restricting excessive displacement of the diaphragm 35 downward, The stopper 38 is provided with a large-diameter bowl-shaped disk part 38c, and the large-diameter bowl-shaped disk part 38c is contacted and locked to the lower surface side pressure chamber defining part 32B of the diaphragm holding member 32. A flat plate portion 32g is provided.

JP 2007-240041 A JP2011-007355A

  However, in the diaphragm 35 provided with the two and half mountain wave-shaped portions 35b formed of the first, second, and third peaks M1, M2, and M3, the following problem occurs.

  That is, as shown in FIG. 4A, when the diaphragm 35 is greatly displaced upward, the inner peripheral portion 35c of the diaphragm 35 contacts the lower surface on the inner peripheral side of the annular flat plate portion 32d which is the upper stopper 51. Before being stopped, the top of the first mountain M1 comes into contact with the lower surface of the annular flat plate portion 32d, and then the diaphragm 35 has an inner peripheral portion 35c as shown in FIG. It is displaced further upward by a distance corresponding to the height H of the first peak M1 until it is contacted and locked to the inner peripheral lower surface of the annular flat plate portion 32d. Therefore, after the top of the first peak M1 contacts the inner peripheral lower surface of the annular flat plate portion 32d, the inner peripheral portion 35c is contacted and locked to the inner peripheral lower surface of the annular flat plate portion 32d. Since the first peak M1 is greatly deformed so as to be flat, a large stress is generated in the first peak M1. Such an event occurs frequently during operation of a system in which the control valve is used as, for example, an expansion valve. Therefore, stress is repeatedly generated in the first peak M1, and the original part remains undesirably deformed. It becomes difficult to return or breakage due to metal fatigue, and the durability and reliability of the diaphragm device and consequently the fluid control valve are lowered.

  The present invention has been made in view of such a problem, and the object of the present invention is to reduce the pressure between the upper surface side pressure and the lower surface side pressure of the diaphragm without requiring a thin diaphragm or an increase in the diameter thereof. Diaphragm type fluid control that can greatly change the lift amount with respect to the change in differential pressure, and can hardly cause undesired deformation or breakage in the diaphragm, and can improve durability, reliability, etc. To provide a valve.

In order to achieve the above object, a diaphragm type fluid control valve according to the present invention is basically a diaphragm type fluid control valve provided with a diaphragm device for driving a valve body in a valve opening / closing direction. The diaphragm device includes a diaphragm, and a diaphragm holding member having a substantially lid-like upper surface side pressure chamber defining portion defining a pressure chamber on the upper surface side of the diaphragm, and the diaphragm includes an inner peripheral portion thereof, A crest-like portion having a concentric annular shape in plan view having at least one convex crest as viewed in cross section is formed between the outer peripheral portion, and the upper surface side pressure chamber defining portion includes a central truncated cone portion, A radius of the upper surface pressure chamber defining portion is formed into a substantially lid shape having an annular flat plate portion connected to the lower portion of the central truncated cone portion and an upper clamping portion for sealing and fixing the outer peripheral portion of the diaphragm. In the middle direction To limit the displacement of the upward of the diaphragm, together with a stopper on the inner peripheral portion of the diaphragm is locked abutment engagement is provided on the inner peripheral lower surface of the annular flat plate portion, on the in the annular flat plate portion on the outer peripheral side of the stopper, the mountain portion inner peripheral portion of the diaphragm is located on the most inner circumferential side of the mountainous-wave portion in the state of being locked abutment engaged on said stopper prevents upward displacement of the diaphragm It is characterized in that an annular groove or void is provided on the upper side for receiving without any problems.

In another preferred aspect, a lower protrusion as the upper stopper is provided at a radial intermediate portion in the upper surface side pressure chamber defining part, and an outer peripheral side of the lower protrusion is located on the innermost peripheral side. The peak portion is defined as the space for receiving the diaphragm without disturbing the upward displacement of the diaphragm .

  In a more preferred embodiment, the above-mentioned peak-like portion has a peak that is convex upward when viewed in cross section, where N is a positive integer (1, 2, 3,...), [N + (0.25 to 0). .75) pieces] are formed.

In the diaphragm type fluid control valve according to the present invention, the innermost part of the mountain wave-shaped part in the state where the inner peripheral part of the diaphragm is in contact with and locked to the upper stopper on the outer peripheral side from the upper stopper in the upper pressure chamber defining part. By providing an annular groove or space for receiving the crest portion located on the circumferential side without disturbing the upward displacement of the diaphragm, the diaphragm is greatly displaced upward, and the inner peripheral portion of the diaphragm Even when the upper stopper is in contact with and locked to the upper stopper, the peak portion located on the innermost circumferential side is received in the annular groove or void without disturbing the upward displacement of the diaphragm. No large stress is generated in the mountain portion located at the position of the ridge, so that it is reliably avoided that the mountain portion cannot be restored to its original state or damaged while being undesirably deformed. Result, the diaphragm device, the durability of the thus fluid control valve, the reliability is improved.

(A) is a longitudinal cross-sectional view which shows the diaphragm apparatus part of one Example of the diaphragm type fluid control valve based on this invention, (B) is an enlarged view of the B section of (A). The longitudinal cross-sectional view which shows the diaphragm apparatus part of the other Example of the diaphragm type fluid control valve based on this invention. The longitudinal cross-sectional view which shows the diaphragm apparatus part of an example of the conventional diaphragm type fluid control valve. FIG. 4 is a diagram used for explaining the problem of the conventional diaphragm device shown in FIG. 3.

  Hereinafter, embodiments of the diaphragm type fluid control valve of the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing a diaphragm device in an embodiment of a diaphragm type fluid control valve according to the present invention. In FIG. 1, portions corresponding to the respective portions of the diaphragm device 30G of the conventional example shown in FIGS. 3 and 4 are denoted by the same reference numerals, and redundant description will be omitted, and the differences will be mainly described below. .

The diaphragm device 30A of the present embodiment has basically the same configuration as the diaphragm device 30G of the conventional example shown in FIGS. 3 and 4 described above, but of the annular flat plate portion 32d of the upper surface side pressure chamber defining portion 32A. In the state where the lower surface of the inner peripheral portion is the upper stopper 51 and the inner peripheral portion 35c of the diaphragm 35 is abutted and locked to the upper stopper 51 on the outer peripheral side of the upper stopper 51 portion in the annular flat plate portion 32d. In order to receive the first peak M1 portion located on the innermost peripheral side of the wave-like portion 35b without obstructing the upward displacement of the diaphragm 35, the inner shape of the cross-section recessed upward is substantially similar to the first peak M1. An annular groove 52 is provided. The depth J of the annular groove 52 is set to be approximately the same as or slightly deeper than the height H of the first peak M1.

Thus, the annular flat plate portion 32d is provided with the annular groove 52 recessed upward, so that the diaphragm 35 is greatly displaced upward, and the inner peripheral portion 35c of the diaphragm 35 is the upper flat plate portion 32d. Even in the state of being contacted and locked to the lower surface of the inner peripheral portion of the first portion, the first peak M1 portion is received in the annular groove 52 without interfering with the upward displacement of the diaphragm 35 . No large stress is generated in the first mountain M1 portion, so that it is reliably avoided that the first mountain M1 portion is undesirably deformed and cannot be restored or damaged, and as a result, the diaphragm device 30A. As a result, the durability and reliability of the fluid control valve 1 are improved.

  In addition, since the effect by having 2.5 [N pieces + (0.25 to 0.75)] the convex peak is the same as the conventional example shown in FIG. 3 and FIG. Omitted.

  FIG. 2 is a longitudinal sectional view showing a diaphragm device 30B in another embodiment of the diaphragm type fluid control valve according to the present invention. In FIG. 2, portions corresponding to the respective portions of the conventional diaphragm device 30 </ b> G shown in FIGS. 3 and 4 are denoted by the same reference numerals and redundant description is omitted, and the differences will be mainly described below. .

In the diaphragm device 30B of this embodiment, the radial intermediate portion (the lower surface of the inner peripheral portion of the annular flat plate portion 32d) of the upper surface side pressure chamber defining portion 32A is positioned slightly above the embodiment shown in FIG. An annular lower protrusion 53 as an upper stopper is provided on the lower surface of the inner peripheral portion of the annular flat plate portion 32d, and the upper displacement limiting position of the diaphragm 35 is the same as that shown in FIG. the outer peripheral side of the downward projecting portion 53, the first mountain M1 portion located innermost in the mountainous-wave portion 35b in a state where the inner peripheral portion 35c of the diaphragm 35 are sealed abutment engagement with the upper stopper 53, the diaphragm It is a space 54 for receiving the upper 35 without being obstructed . The downward protrusion height K of the annular downward protrusion 53 from the lower surface of the annular flat plate portion 32d is set to be approximately the same as or slightly higher than the height H of the first peak M1.

  The diaphragm device 30 </ b> B having such a configuration and the fluid control valve 2 including the diaphragm device 30 </ b> B can provide substantially the same operational effects as the above-described embodiment.

1, 2 Diaphragm type fluid control valve (expansion valve)
12 Lower surface side pressure chambers 30A, 30B Diaphragm device 32 Diaphragm holding member 32A Upper surface side pressure chamber defining portion 32B Lower surface side pressure chamber defining portion 32d Annular flat plate portion 33 Upper surface side pressure chamber 35 Diaphragm 35a Outer peripheral portion 35b Mountain wave portion 35c Inside Peripheral part 37 Actuating rod 51 Upper stopper (Inner peripheral part lower surface of annular flat plate part)
52 annular groove 53 upper stopper (annular downward projection)
54 void M1 first mountain

Claims (3)

A diaphragm type fluid control valve provided with a diaphragm device for driving the valve body in the valve opening and closing direction,
The diaphragm device includes a diaphragm, and a diaphragm holding member having a substantially lid-shaped upper surface side pressure chamber defining portion that defines a pressure chamber on the upper surface side of the diaphragm,
The diaphragm is formed between the inner peripheral portion and the outer peripheral portion, a mountain wave-like portion having a concentric annular shape in a plan view having at least one convex peak when viewed in cross section,
The upper surface side pressure chamber defining part has a central frustoconical part, an annular flat plate part connected to the lower part of the central frustoconical part, and an upper lid part for sealing and fixing the outer peripheral part of the diaphragm It is said that
A radially intermediate portion of the upper surface side pressure chamber defining portion, to limit the displacement of the upward of the diaphragm, the stopper on the inner peripheral portion of the diaphragm is locked abutment engagement is of the annular flat portion Provided on the lower surface of the peripheral portion, and on the outer peripheral side of the upper stopper in the annular flat plate portion , the innermost peripheral side of the mountain wave-shaped portion in a state where the inner peripheral portion of the diaphragm is abutted and locked to the upper stopper the mountain portion, a diaphragm-actuated fluid control valve, characterized in that the annular groove or cavity recessed in an upper for receiving without interfering with the upper displacement of the diaphragm is provided located. A radially intermediate portion of the upper surface side pressure chamber defining section, together with the downward projecting portion as the upper stopper is provided, the outer peripheral side of said lower protrusions, the peak portions located at the innermost, the 2. A diaphragm type fluid control valve according to claim 1, wherein said diaphragm type fluid control valve is provided for receiving the diaphragm without disturbing the upward displacement of the diaphragm. In the above-mentioned peak-like portion, a peak that is convex upward when viewed in cross section is defined as [N + (0.25-0.75)] where N is a positive integer (1, 2, 3,...). 3. The diaphragm type fluid control valve according to claim 1, wherein the diaphragm type fluid control valve is formed.

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