EP4067777A1

EP4067777A1 - Power element and expansion valve used therein

Info

Publication number: EP4067777A1
Application number: EP22163460.3A
Authority: EP
Inventors: Junya Hayakawa; Kinya Okutsu; Kouhei Kubota
Original assignee: Fujikoki Corp
Current assignee: Fujikoki Corp
Priority date: 2021-03-29
Filing date: 2022-03-22
Publication date: 2022-10-05
Also published as: JP2022152982A; JP7373857B2; CN115127260A

Abstract

Provided are an expansion valve and power element used therein that are capable of maintaining sealability while reducing the size of the expansion valve and suppressing deterioration of controllability. The expansion valve comprises a valve main body; a power element mounted on the valve main body; and a seal provided between the valve main body and the power element, wherein: the power element includes: an upper lid member; a receiving member; and a diaphragm interposed between the upper lid member and the receiving member, the receiving member is formed by press working, and includes a cylindrical portion and an annular flange portion that is adjacent to the cylindrical portion and extends in an outer circumferential direction of the cylindrical portion, the cylindrical portion of the receiving member is fixed to the valve main body, and the seal is provided in a seal space formed between the cylindrical portion, the annular flange portion, and the valve main body, and a cutting process is performed on a region of the cylindrical portion adjacent to the annular flange portion, and the region forms a part of the seal space.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2021-055966, filed March 29, 2021 . The contents of this application are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to a power element and an expansion valve used therein.

SUMMARY OF THE INVENTION

Conventionally, in the refrigeration cycles used in air conditioners or the like mounted in automobiles, temperature-sensitive expansion valves are used that adjust the amount of refrigerant passing through according to the temperature.
For example, the expansion valve illustrated in Japanese Unexamined Patent Application Publication No. 2017-198373 (Patent Document 1) has an inlet port into which a high-pressure refrigerant is introduced and a valve chamber communicating with the inlet port, and the top of a valve main body is equipped with a drive mechanism for a valve member, referred to as a power element. A spherical valve element arranged in the valve chamber faces a valve seat that opens in the valve chamber, and is operated by an operation rod driven by the power element to control the opening of the throttle passage with the valve seat.
The power element is composed of an upper lid member that forms a pressure working chamber, a thin plate diaphragm that elastically deforms under pressure, and a receiving member that is fixed to the valve main body. In addition, a working gas is enclosed in the pressure working chamber formed by the upper lid member and the diaphragm. Further, a stopper member is arranged in the lower space between the diaphragm and the receiving member.
In such a power element, heat is transferred between the refrigerant flowing from the valve main body into the lower space and the working gas of the pressure working chamber, and as a result, when the internal pressure of the pressure working chamber is relatively increased, the diaphragm deforms so as to expand the pressure working chamber, thereby pressing the stopper member to press the operation rod and separate the valve element from the valve seat. On the other hand, when the internal pressure of the pressure working chamber relatively decreases, the deformation of the diaphragm reverses, and the pressing force of the operation rod disappears, so that the valve element sits on the valve seat.
Incidentally, it is desirable to reduce the weight of vehicle bodies for the purpose of suppressing the fuel consumption of automobiles, and accordingly, there is a demand for miniaturization and weight reduction with respect to in-vehicle components like expansion valves. However, if the power element is miniaturized in accordance with the miniaturization of the valve main body, the flow of the refrigerant flowing from the valve main body into the lower space of the power element may change, resulting in deterioration of controllability.
Accordingly, it has been proposed to miniaturize the valve main body without miniaturizing the power element in order to miniaturize the expansion valve while suppressing the deterioration of controllability. However, according to the results of consideration by the present inventors, in the case that the valve main body is miniaturized without miniaturizing the power element, it has been found that the sealing properties between the power element and the valve main body deteriorate.
Accordingly, an object of the present invention is to provide a power element and an expansion valve used therein that are capable of maintaining sealability while reducing the size of the expansion valve and suppressing deterioration of controllability.
In order to achieve the above object, the expansion valve according to the present invention includes a valve main body; a power element mounted on the valve main body; and a seal provided between the valve main body and the power element. The power element includes: an upper lid member; a receiving member; and a diaphragm interposed between the upper lid member and the receiving member, the receiving member is formed by press working, and includes a cylindrical portion and an annular flange portion that is adjacent to the cylindrical portion and extends in an outer circumferential direction of the cylindrical portion, the cylindrical portion of the receiving member is fixed to the valve main body, and the seal is provided in a seal space formed between the cylindrical portion, the annular flange portion, and the valve main body, and a cutting process is performed on a region of the cylindrical portion adjacent to the annular flange portion, and the region forms a part of the seal space.
According to the present invention, it is possible to provide a power element and an expansion valve used therein that are capable of maintaining sealability while reducing the size of the expansion valve and suppressing deterioration of controllability.

BRIEF DESCRIPTION OF THE DRAWINGS

[Figure 1] FIG. 1 is a schematic cross-sectional view schematically illustrating an example in which the expansion valve according to the present embodiments is applied to a refrigerant circulation system.
[Figure 2] FIG. 2 is an enlarged cross-sectional view illustrating the vicinity of the power element in the expansion valve of FIG 1.
[Figure 3] FIG. 3 is a cross-sectional view illustrating the power element of the present embodiment alone.
[Figure 4] FIG. 4 is an enlarged cross-sectional view illustrating the vicinity of the power element of the expansion valve according to the second embodiment.
[Figure 5] FIG. 5 is a cross-sectional view illustrating the power element of the present embodiment alone.

DETAILED DESCRIPTION

Hereinafter, the embodiments according to the present invention will be described with reference to the figures.

(Definition of Directions)

In the present specification, the direction extending from the valve element 3 toward the operation rod 5 is defined as the "upward direction," and the direction extending from the operation rod 5 toward the valve element 3 is defined as the "downward direction." Accordingly, in the present specification, the direction extending from the valve element 3 toward the operation rod 5 is referred to as the "upward direction" regardless of the orientation of the expansion valve 1.

(First Embodiment)

An overview of the expansion valve 1 according to the present embodiments will be described with reference to FIG. 1 and FIG. 2. FIG. 1 is a schematic cross-sectional view schematically illustrating an example in which the expansion valve 1 according to the present embodiments is applied to a refrigerant circulation system 100. FIG. 2 is an enlarged cross-sectional view illustrating the vicinity of the power element in the expansion valve of FIG 1. FIG. 3 is a cross-sectional view illustrating the power element of the present embodiment alone.
In the present embodiment, the expansion valve 1 is fluidly connected to a compressor 101, a condenser 102, and an evaporator 104. L is set as the axis of the expansion valve 1.
In FIG. 1, the expansion valve 1 includes a valve main body 2 having a valve chamber VS, a valve element 3, a biasing device 4, an operation rod 5, and a power element 8.
The valve main body 2 includes a first flow path 21, a second flow path 22, an intermediate chamber 221, and a return flow path 23 in addition to the valve chamber VS. The first flow path 21 is a supply-side flow path, and a refrigerant (also referred to as a fluid) is supplied to the valve chamber VS via the supply-side flow path. The second flow path 22 is a discharge-side flow path (also referred to as an outlet-side flow path), and the fluid in the valve chamber VS is discharged to the outside of the expansion valve through a valve through-hole 27, the intermediate chamber 221 and the discharge-side flow path.
The first flow path 21 and the valve chamber VS communicate with each other by a connection path 21a having a smaller diameter than the first flow path 21. The valve chamber VS and the intermediate chamber 221 communicate with each other via the valve seat 20 and the valve through-hole 27.
The operation rod insertion hole 28 formed above the intermediate chamber 221 has a function for guiding the operation rod 5, and the annular recess 29 formed above the operation rod insertion hole 28 has a function of accommodating a ring spring 6. The ring spring 6 applies a predetermined biasing force by coming into contact with a plurality of springs on the outer circumference of the operation rod 5.
The valve element 3 is arranged in the valve chamber VS. When the valve element 3 is seated on the valve seat 20 of the valve main body 2, the flow of the refrigerant through the valve through-hole 27 is restricted. This state is referred to as a non-communicating state. However, even in the case that the valve element 3 is seated on the valve seat 20, a limited amount of refrigerant may flow. On the other hand, when the valve element 3 is separated from the valve seat 20, the flow of the refrigerant passing through the valve through-hole 27 increases. This state is referred to as a communication state.
The operation rod 5 is inserted into the valve through-hole 27 with a predetermined gap. The lower end of the operation rod 5 is in contact with the upper surface of the valve element 3. The upper end of the operation rod 5 is fitted into a fitting hole 84c of the stopper member 84, which will be described later.
The operation rod 5 can press the valve element 3 in a valve opening direction against the biasing force of the biasing device 4. When the operation rod 5 moves downward, the valve element 3 is separated from the valve seat 20 and the expansion valve 1 is opened.
The biasing device 4 includes a coil spring 41 in which a wire member having a circular cross section is spirally wound, a valve element support 42, and a spring receiving member 43.
The valve element support 42 is attached to the upper end of the coil spring 41, a spherical valve element 3 is welded to the upper surface thereof, and both are integrated together.
The spring receiving member 43 that supports the lower end of the coil spring 41 can be screwed against the valve main body 2, and has a function of sealing the valve chamber VS and a function of adjusting the biasing force of the coil spring 41.
Next, the power element 8 will be described. As illustrated in FIG. 2, the power element 8 includes a plug 81, an upper lid member 82, a diaphragm 83, a receiving member 86, and a stopper member 84.
An opening 82a is formed at the top of the substantially conical upper lid member 82, and can be sealed by the plug 81.
The diaphragm 83 is made of a thin metal (SUS, for example) plate material in which a plurality of concentric, uneven shapes are formed, and has an outer diameter substantially the same as the outer diameter of the upper lid member 82 and the receiving member 86.
The receiving member 86 includes a first annular flange portion 86a having an outer diameter substantially the same as the outer diameter of the upper lid member 82, a first cylindrical portion 86b which is connected to the inner circumference of the first annular flange portion 86a, a second annular flange portion 86c which is connected to the lower end of the first cylindrical portion 86b and extends inward in the radial direction, and a second cylindrical portion 86d which is connected to the inner circumference of the second annular flange portion 86c. A male screw portion 86e is formed on the outer circumference of the second cylindrical portion 86d on the lower end side.
Here, a method of manufacturing the receiving member 86 will be described. First a metal plate material is press-molded to form the first annular flange portion 86a, the first cylindrical portion 86b, the second annular flange portion 86c and the second cylindrical portion 86d. After the press-molding, as illustrated by the dotted line in FIG. 3, a transition portion TF having an arcuate cross section (a taper shape that increases in diameter toward the top) that may reduce the sealing properties of the seal is generated at a boundary portion between the second annular flange portion 86c and the second cylindrical portion 86d that extend in directions orthogonal to each other.
More specifically, first, in order to suppress the deterioration of controllability of the valve element 3, it is necessary to secure a large inner diameter of the second cylindrical portion 86d, and so a method that does not miniaturize the power element 8 is used. In such a case, if the valve main body 2 is miniaturized in order to miniaturize the entire expansion valve 1, the area of the upper end surface of the valve main body 2 is reduced. When the power element 8 in which the transition portion TF is generated is attached to the valve main body 2, the volume of the seal space SP (FIG. 2) formed between the receiving member 86 and the seal recess 2c of the valve main body 2 (between the second cylindrical portion 86d, the second annular flange portion 86c, and the valve main body 2) is limited by the transition portion TF. Accordingly, the filling rate of the ring-shaped seal (also referred to as packing) SL housed in the seal space SP may exceed 100%, and there is a risk that the seal SL may protrude. If a seal SL having a small cross section is adopted to prevent this, the sealing properties of the seal SL may be lowered, and the durability of the seal SL may also be lowered.
Accordingly, in the present embodiment, after press molding, a cutting process is performed on the second cylindrical portion 86d adjacent to the second annular flange portion 86c to remove the transition portion TF. More specifically, the receiving member 86 is gripped by the chuck, and the cutting tool is brought closer along the second annular flange portion 86c from the radial direction while rotating around the axis L. In the seal recess 2c in the radial direction, a cutting process is performed on the transition portion TF to form a cylindrical surface parallel to the axis L, and the flat lower surface of the second annular flange portion 86c is expanded. In addition, the male screw portion 86e is formed on the outer circumference of the second cylindrical portion 86d by a cutting process or the like without separating from the chuck. It should be noted that, even after cut processing, the fine R-shape of the rake face of the cutting tool is transferred to the boundary portion between the second annular flange portion 86c and the second cylindrical portion 86d, but since the R-shape is much smaller than the transition portion TF formed by press working, the volume of the seal space SP is hardly limited.
According to the present embodiment, in the second cylindrical portion 86d, the space between the second annular flange portion 86c and the male screw portion 86e (the region adjacent to the second annular flange portion 86c) is a cut-processed cylindrical surface and forms a part of the seal space SP, such that a large seal space SP formed between the receiving member 86 and the seal recess 2c of the valve main body 2 can be secured. Accordingly, a seal SL having a relatively large cross section (here, a rectangular cross section) can be adopted, and the sealing performance and durability of the seal can be improved.
The stopper member 84 includes a disc portion 84a facing the diaphragm 83, a cylindrical main body 84b connected below the disc portion 84a, and a bag hole-shaped fitting hole 84c formed in the center of the lower surface of the main body 84b. The outer circumference of the lower surface of the disc portion 84a is supported by the upper surface of the second annular flange portion 86c.
The procedure for assembling the power element 8 will be described. While placing the stopper member 84 between the diaphragm 83 and the receiving member 86, the outer circumferential portions of the upper lid member 82, the diaphragm 83, and the receiving member 86 are overlapped with each other, and the outer circumferential portions are circumferentially welded by, for example, TIG welding, laser welding, plasma welding, or the like to integrate them.
Subsequently, the working gas is sealed in the space (referred to as the pressure working chamber PO) surrounded by the upper lid member 82 and the diaphragm 83 from the opening 82a formed in the upper lid member 82, and then the opening 82a is sealed with the plug 81. Further, the plug 81 is fixed to the upper lid member 82 by projection welding or the like.
At this time, since the diaphragm 83 receives pressure in a form of projecting toward the receiving member 86 due to the working gas sealed in the pressure working chamber PO, it is supported in contact with the upper surface of the stopper member 84 arranged in the lower space LS surrounded by the diaphragm 83 and the receiving member 86.
When the power element 8 assembled as described above is assembled to the valve main body 2, the male screw portion 86e provided on the outer circumference of the lower end of the second cylindrical portion 86d of the receiving member 86 is screwed into the female screw portion 2b formed on the inner circumference of the recess 2a communicating with the return flow path 23 of the valve main body 2. When the male screw portion 86e is screwed with respect to the female screw portion 2b, the lower end of the receiving member 86 comes into contact with the upper end surface of the valve main body 2. As a result, the power element 8 can be fixed to the valve main body 2.
At this time, the seal SL interposed in the seal space SP between the power element 8 and the valve main body 2 prevents the refrigerant from leaking from the recess 2a when the power element 8 is attached to the valve main body 2. In such a state, the lower space LS of the power element 8 communicates with the return flow path 23; that is, the same internal pressure is obtained.

(Operation of the Expansion Valve)

An example of the operation of the expansion valve 1 will be described with reference to FIG. 1. The refrigerant pressurized by the compressor 101 is liquefied by the condenser 102 and sent to the expansion valve 1. Further, the refrigerant adiabatically expanded by the expansion valve 1 is sent to the evaporator 104, and the evaporator 104 exchanges heat with the air flowing around the evaporator. The refrigerant returning from the evaporator 104 is returned to the compressor 101 side through the expansion valve 1 (more specifically, the return flow path 23). At this time, by passing through the evaporator 104, the fluid pressure in the second flow path 22 becomes larger than the fluid pressure in the return flow path 23.
A high-pressure refrigerant is supplied to the expansion valve 1 from the condenser 102. More specifically, the high-pressure refrigerant from the condenser 102 is supplied to the valve chamber VS via the first flow path 21.
When the valve element 3 is seated on the valve seat 20 (when in the non-communicating state), the flow rate of the refrigerant sent from the valve chamber VS to the evaporator 104 through the valve through-hole 27, the intermediate chamber 221 and the second flow path 22 is limited. On the other hand, when the valve element 3 is separated from the valve seat 20 (when in the communicating state), the flow rate of the refrigerant sent from the valve chamber VS to the evaporator 104 through the valve through-hole 27, the intermediate chamber 221 and the second flow path 22 increases. Switching between the closed state and the open state of the expansion valve 1 is performed by the operation rod 5 connected to the power element 8 via the stopper member 84.
In FIG. 1, a pressure working chamber PO and a lower space LS partitioned by a diaphragm 83 are provided inside the power element 8. Accordingly, when the working gas in the pressure working chamber PO is liquefied, the diaphragm 83 and the stopper member 84 rise, such that the operation rod 5 moves upward according to the biasing force of the coil spring 41. On the other hand, when the liquefied working gas is vaporized, the diaphragm 83 and the stopper member 84 are pressed downward, such that the operation rod 5 moves downward. In this way, the expansion valve 1 is switched between an open state and a closed state.
Further, the lower space LS of the power element 8 communicates with the return flow path 23. Accordingly, the volume of the working gas in the pressure working chamber PO changes according to the temperature and pressure of the refrigerant flowing through the return flow path 23, and the operation rod 5 is driven. In other words, in the expansion valve 1 illustrated in FIG. 1, the amount of the refrigerant supplied from the expansion valve 1 toward the evaporator 104 is automatically adjusted according to the temperature and pressure of the refrigerant returning from the evaporator 104 to the expansion valve 1.
According to this embodiment, since the power element 8 is not miniaturized, it is not necessary to change the inner diameter of the receiving member 86, and since the flow of the refrigerant flowing from the return flow path 23 into the lower space LS does not change, deterioration of the controllability of the valve element 3 can be suppressed. It should be noted that the deterioration of the controllability means that an actual value greatly exceeds a target value or that an actual value fluctuates up or down with respect to a target value.

(Second Embodiment)

FIG. 4 is an enlarged cross-sectional view illustrating the vicinity of the power element of the expansion valve according to the second embodiment. FIG. 5 is a cross-sectional view illustrating the power element 8A of the present embodiment alone. The present embodiment differs from the above-described embodiment only in the shape of the receiving member 86A of the power element 8A. Since the other configurations are the same as those in the above-described embodiment, the same reference numerals are given and redundant description will be omitted.
A method of manufacturing the receiving member 86A will be described. Similar to the embodiment described above, a metal plate material is press-molded to form a first annular flange portion 86Aa, a first cylindrical portion 86Ab, a second annular flange portion 86Ac, and a second cylindrical portion 86Ad.
Further, after the press-molding, a reduced diameter portion 86Af is formed by performing a cutting process on the boundary portion between the second annular flange portion 86Ac and the second cylindrical portion 86Ad that extend in directions orthogonal to each other. The outer diameter of the reduced diameter portion 86Af is smaller than the thread outer diameter of the male screw portion 86Ae.
According to the present embodiment, by forming the reduced diameter portion 86Af between the second annular flange portion 86Ac and the male screw portion 86Ae, a larger seal space SP formed between the receiving member 86A and the seal recess 2c of the valve main body 2 can be secured. Accordingly, a seal SL having a larger cross section can be adopted, and the sealability and durability of the seal can be improved.
It should be noted that the present invention is not limited to the above-described embodiments. Within the scope of the present invention, any component of the above-described embodiments can be modified. In addition, any component can be added or omitted in the above-described embodiments.

[Reference Signs List]

1...: Expansion valve
2...: Valve main body
3...: Valve element
4...: Biasing device
5...: Operation rod
6...: Ring spring
8, 8A...: Power element
20...: Valve seat
21...: First flow path
22...: Second flow path
23...: Return flow path
27...: Valve through-hole
41...: Coil spring
42...: Valve element support
43...: Spring receiving member
100...: Refrigerant circulation system
101...: Compressor
102...: Condenser
104...: Evaporator
VS...: Valve chamber

Claims

An expansion valve comprising:
a valve main body;

a power element mounted on the valve main body; and

a seal provided between the valve main body and the power element,
wherein:
the power element includes:
an upper lid member;

a receiving member; and

a diaphragm interposed between the upper lid member and the receiving member,

the receiving member is formed by press working, and includes a cylindrical portion and an annular flange portion that is adjacent to the cylindrical portion and extends in an outer circumferential direction of the cylindrical portion,

the cylindrical portion of the receiving member is fixed to the valve main body, and the seal is provided in a seal space formed between the cylindrical portion, the annular flange portion, and the valve main body, and

a cutting process is performed on a region of the cylindrical portion adjacent to the annular flange portion, and the region forms a part of the seal space.
The expansion valve according to claim 1, wherein:
a cutting process is performed on the cylindrical portion in parallel with an axis of the power element.
The expansion valve according to claim 1 or 2, wherein:
the cylindrical portion includes a male screw portion; and

a cutting process is performed on the cylindrical portion so as to form a reduced diameter portion having an outer diameter smaller than that of the male screw portion.
The expansion valve according to any one of claim 1 to 3, wherein:
a seal recess is formed in the valve main body so as to oppose the annular flange portion; and

a cutting process is performed on the cylindrical portion on a radial inner side of the seal recess.
The expansion valve according to any one of claim 1 to 4, wherein:
the cylindrical portion and the annular flange portion are bent by press molding.
A power element used in an expansion valve including:
a valve main body;

a power element mounted on the valve main body; and

a seal provided between the valve main body and the power element,

the power element comprising:
an upper lid member;

a receiving member; and

a diaphragm interposed between the upper lid member and the receiving member, wherein:
the receiving member is formed by press working, and includes a cylindrical portion and an annular flange portion that is adjacent to the cylindrical portion and extends in an outer circumferential direction of the cylindrical portion,

the cylindrical portion of the receiving member is fixed to the valve main body, and the seal is provided in a seal space formed between the cylindrical portion, the annular flange portion, and the valve main body, and

a cutting process is performed on a region of the cylindrical portion adjacent to the annular flange portion, and the region forms a part of the seal space.