JP7373857B2 - Power element and expansion valve using it - Google Patents

Description

The present invention relates to a power element and an expansion valve using the power element.

2. Description of the Related Art Conventionally, in a refrigeration cycle used in an air conditioner installed in an automobile, a temperature-sensitive expansion valve is used to adjust the amount of refrigerant passing through depending on the temperature.

For example, the expansion valve shown in 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 a drive mechanism for a valve member called a power element is mounted on the top of the valve body. be equipped. A spherical valve body placed inside the valve chamber faces the valve seat that opens into the valve chamber, and is operated by an actuation rod driven by a power element to control the opening of the throttle passage between the valve seat and the valve seat. do.

The power element is composed of an upper lid member that forms a pressure operating chamber, a thin plate diaphragm that elastically deforms in response to pressure, and a receiving member that is fixed to the valve body. Further, a working gas is sealed in a pressure working chamber formed by the upper lid member and the diaphragm. Furthermore, a stopper member is disposed in the lower space between the diaphragm and the receiving member.

In such a power element, heat transfer occurs between the refrigerant flowing into the lower space from the valve body and the working gas in the pressure working chamber, and when the internal pressure of the pressure working chamber increases relatively, the pressure working chamber The diaphragm deforms so as to expand, thereby pushing the stopper member and pressing the actuating rod, thereby separating the valve body from the valve seat. On the other hand, when the internal pressure of the pressure working chamber decreases relatively, the diaphragm returns to its original deformation and the pressing force of the working rod disappears, so that the valve body seats on the valve seat.

Japanese Patent Application Publication No. 2017-198373

Incidentally, there is a desire to reduce the weight of automobile bodies for the purpose of reducing fuel consumption of automobiles, and there is also a demand for reductions in size and weight of expansion valves, which are in-vehicle components. However, if the power element is downsized to match the downsizing of the valve body, the flow of refrigerant flowing from the valve body into the lower space of the power element may change, resulting in poor controllability.

Therefore, it has been proposed to downsize the expansion valve while suppressing deterioration in controllability by downsizing the valve body without downsizing the power element. However, according to the study results of the present inventors, it has been found that when the valve body is downsized without downsizing the power element, the sealing performance between the power element and the valve body deteriorates.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a power element that can reduce the size of an expansion valve while suppressing deterioration in controllability and maintain sealing performance, and an expansion valve using the power element.

In order to achieve the above object, the power element according to the present invention includes:
A power element including an upper lid member, a receiving member, and a diaphragm sandwiched between the upper lid member and the receiving member,
The receiving member is formed by press working, and has a cylindrical part and an annular flange part adjacent to the cylindrical part and extending in an outer circumferential direction of the cylindrical part,
The cylindrical portion includes a male threaded portion, and a portion of the cylindrical portion adjacent to the annular flange portion is cut to form a reduced diameter portion having a smaller outer diameter than the male threaded portion. It is characterized by
The power element according to the invention comprises:
A power element including an upper lid member, a receiving member, and a diaphragm sandwiched between the upper lid member and the receiving member,
The receiving member is formed by press working, and has a cylindrical part and an annular flange part adjacent to the cylindrical part and extending in an outer circumferential direction of the cylindrical part,
The power element is attachable to the valve body,
A seal recess is formed in the valve body opposite to the annular flange,
A cutting process is performed on a portion of the cylindrical portion adjacent to the annular flange portion and radially aligned with the seal recess;
It is characterized by

According to the present invention, it is possible to provide a power element that can reduce the size of an expansion valve while suppressing deterioration in controllability and maintain sealing performance, and an expansion valve using the power element.

FIG. 1 is a schematic sectional view schematically showing an example in which the expansion valve according to the present embodiment is applied to a refrigerant circulation system. FIG. 2 is an enlarged sectional view showing the vicinity of the power element in the expansion valve of FIG. 1. FIG. FIG. 3 is a sectional view showing the power element of this embodiment alone. FIG. 4 is an enlarged sectional view showing the vicinity of the power element of the expansion valve according to the second embodiment. FIG. 5 is a sectional view showing the power element of this embodiment alone.

Embodiments according to the present invention will be described below with reference to the drawings.

(Definition of direction)
In this specification, the direction from the valve body 3 toward the actuation rod 5 is defined as an "upward direction," and the direction from the actuation rod 5 toward the valve body 3 is defined as a "downward direction." Therefore, in this specification, the direction from the valve body 3 toward the actuating rod 5 is referred to as the "upward direction" regardless of the attitude of the expansion valve 1.

(First embodiment)
An overview of the expansion valve 1 in this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic sectional view schematically showing an example in which the expansion valve 1 according to the present embodiment is applied to a refrigerant circulation system 100. FIG. 2 is an enlarged sectional view showing the vicinity of the power element in the expansion valve of FIG. 1. FIG. FIG. 3 is a sectional view showing the power element of this embodiment alone.

In this embodiment, the expansion valve 1 is fluidly connected to a compressor 101, a condenser 102, and an evaporator 104. Let L be the axis of the expansion valve 1.

In FIG. 1, an expansion valve 1 includes a valve body 2 including a valve chamber VS, a valve body 3, a biasing device 4, an actuation rod 5, and a power element 8.

The valve 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 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 via the valve passage hole 27, the intermediate chamber 221, and the discharge side flow path. be done.

The first flow path 21 and the valve chamber VS communicate with each other through a connecting 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 passage hole 27.

The actuating rod insertion hole 28 formed above the intermediate chamber 221 has the function of guiding the actuating rod 5, and the annular recess 29 formed above the actuating rod insertion hole 28 has the function of accommodating the ring spring 6. has. The ring spring 6 has a plurality of spring pieces brought into contact with the outer periphery of the actuating rod 5 to apply a predetermined biasing force.

The valve body 3 is arranged within the valve chamber VS. When the valve body 3 is seated on the valve seat 20 of the valve body 2, the flow of refrigerant through the valve passage hole 27 is restricted. This state is called a non-communication state. However, even when the valve body 3 is seated on the valve seat 20, a limited amount of refrigerant may flow. On the other hand, when the valve body 3 is spaced apart from the valve seat 20, the flow of refrigerant passing through the valve passage hole 27 increases. This state is called a communication state.

The actuating rod 5 is inserted into the valve passage hole 27 with a predetermined gap. The lower end of the actuating rod 5 is in contact with the upper surface of the valve body 3. The upper end of the actuating rod 5 is fitted into a fitting hole 84c of a stopper member 84, which will be described later.

The actuating rod 5 can press the valve body 3 in the valve opening direction against the urging force of the urging device 4. When the actuating rod 5 moves downward, the valve body 3 separates from the valve seat 20, and the expansion valve 1 becomes open.

The biasing device 4 includes a coil spring 41 made of a wire rod having a circular cross section wound helically, a valve body support 42, and a spring receiving member 43.

The valve body support 42 is attached to the upper end of the coil spring 41, and the spherical valve body 3 is welded to the upper surface of the valve body support 42, so that the two are integrated.

The spring receiving member 43 that supports the lower end of the coil spring 41 can be screwed onto the valve body 2, and has the function of sealing the valve chamber VS and the function of adjusting the biasing force of the coil spring 41. .

Next, the power element 8 will be explained. As shown 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 82 a is formed at the top of the substantially conical upper lid member 82 and can be sealed with a plug 81 .

The diaphragm 83 is made of a thin metal (for example, SUS) plate material with a plurality of concentric concave and convex shapes formed thereon, and has an outer diameter that is approximately the same as the outer diameter of the upper cover member 82 and the receiving member 86 .

The receiving member 86 includes a first annular flange portion 86a having an outer diameter approximately the same as the outer diameter of the upper lid member 82, a first cylindrical portion 86b continuous to the inner circumference of the first annular flange portion 86a, and a first cylindrical portion 86b. It has a second annular flange part 86c connected to the lower end of the part 86b and directed radially inward, and a second cylindrical part 86d connected to the inner periphery of the second annular flange part 86c. A male threaded portion 86e is formed on the outer periphery of the lower end of the second cylindrical portion 86d.

Here, a method of manufacturing the receiving member 86 will be explained. First, a first annular flange portion 86a, a first cylindrical portion 86b, a second annular flange portion 86c, and a second cylindrical portion 86d are formed by press-molding a metal plate material. After press forming, the boundary between the second annular flange part 86c and the second cylindrical part 86d, which extend in directions perpendicular to each other, has an arcuate cross section (with a diameter increasing upward) as shown by the dotted line in FIG. A transition portion TF (tapered shape) occurs, which may reduce the hermeticity of the seal.

To explain more specifically, first, in order to suppress deterioration of controllability of the valve body 3, it is necessary to ensure a large inner diameter of the second cylindrical portion 86d, so the policy is not to downsize the power element 8. In such a case, when the valve body 2 is downsized in order to downsize the entire expansion valve 1, the area of the upper end surface of the valve body 2 becomes smaller. When the power element 8 with the transition portion TF is attached to such a valve 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 body 2 increases. , and will be limited by the transition part TF. Therefore, the filling rate of the ring-shaped seal (also referred to as packing) SL accommodated in the seal space SP may exceed 100%, and the seal SL may protrude. If a seal SL with a small cross section is employed to prevent this, there is a risk that the sealing performance of the seal SL will decrease and the durability of the seal SL will also decrease.

Therefore, in this embodiment, after press molding, the second cylindrical portion 86d adjacent to the second annular flange portion 86c is machined to remove the transition portion TF. More specifically, while gripping the receiving member 86 with a chuck and rotating it around the axis L, a cutting tool is approached from the radial direction along the second annular flange portion 86c, and on the radially inner side of the seal recess 2c, The transition portion TF is cut to form a cylindrical surface parallel to the axis L, and the flat lower surface of the second annular flange portion 86c is expanded. Further, without separating from the chuck, a male threaded portion 86e is formed on the outer periphery of the second cylindrical portion 86d by cutting or the like. Note that even after the cutting process, the fine R shape of the rake face of the cutting tool is transferred to the boundary between the second annular flange part 86c and the second cylindrical part 86d. Since it is much smaller than the transition portion TF to be formed, it hardly limits the volume of the seal space SP.

According to this embodiment, in the second cylindrical portion 86d, there is a cut cylindrical surface between the second annular flange portion 86c and the male threaded portion 86e, so that the receiving member 86 and the valve body 2 are sealed. It is possible to secure a large seal space SP formed between the concave portion 2c and the concave portion 2c. Therefore, a seal SL having a relatively large cross section (here, a rectangular cross section) can be employed, and the sealing performance and durability of the seal can be improved.

The stopper member 84 includes a disk portion 84a facing the diaphragm 83, a cylindrical main body 84b connected below the disk portion 84a, and a blind hole-shaped fitting hole 84c formed at the center of the lower surface of the main body 84b. has. The outer periphery of the lower surface of the disk 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 explained. While disposing the stopper member 84 between the diaphragm 83 and the receiving member 86, the outer peripheral portions of the upper lid member 82, the diaphragm 83, and the receiving member 86 are overlapped, and the outer peripheral portions are welded by, for example, TIG welding, laser welding, or plasma welding. Integrate by welding the circumference by welding, etc.

Subsequently, a working gas is sealed into a space (referred to as a pressure operating chamber PO) surrounded by the upper lid member 82 and the diaphragm 83 through an opening 82a formed in the upper lid member 82, and then the opening 82a is sealed with the stopper 81. Furthermore, the stopper 81 is fixed to the upper lid member 82 using projection welding or the like.

At this time, the diaphragm 83 receives pressure from the working gas sealed in the pressure working chamber PO in a manner that it protrudes toward the receiving member 86. Therefore, a stopper disposed in the lower space LS surrounded by the diaphragm 83 and the receiving member 86 It is supported in contact with the upper surface of the member 84.

When assembling the power element 8 assembled as described above to the valve body 2, the male threaded portion 86e provided on the outer periphery of the lower end of the second cylindrical portion 86d of the receiving member 86 is connected to the return passage 23 of the valve body 2. It is screwed into a female thread 2b formed on the inner periphery of a recess 2a. When the male threaded portion 86e is screwed into the female thread 2b, the lower end of the receiving member 86 comes into contact with the upper end surface of the valve body 2. This allows the power element 8 to be fixed to the valve body 2.

At this time, the seal SL interposed in the seal space SP between the power element 8 and the valve body 2 prevents refrigerant from leaking from the recess 2a when the power element 8 is attached to the valve body 2. In this state, the lower space LS of the power element 8 communicates with the return flow path 23, that is, has the same internal pressure.

(Operation of expansion valve)
An example of the operation of the expansion valve 1 will be described with reference to FIG. The refrigerant pressurized by the compressor 101 is liquefied by the condenser 102 and sent to the expansion valve 1. Further, the refrigerant that has been adiabatically expanded by the expansion valve 1 is sent to the evaporator 104, where it exchanges heat with the air flowing around the evaporator. The refrigerant returning from the evaporator 104 passes through the expansion valve 1 (more specifically, the return passage 23) and is returned to the compressor 101 side. At this time, by passing through the evaporator 104, the fluid pressure in the second flow path 22 becomes greater than the fluid pressure in the return flow path 23.

High-pressure refrigerant is supplied to the expansion valve 1 from a 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 body 3 is seated on the valve seat 20 (in a non-communicating state), it is sent from the valve chamber VS to the evaporator 104 through the valve passage hole 27, the intermediate chamber 221, and the second flow path 22. Refrigerant flow is restricted. On the other hand, when the valve body 3 is separated from the valve seat 20 (in the communicating state), water flows from the valve chamber VS to the evaporator 104 through the valve passage hole 27, the intermediate chamber 221, and the second flow path 22. The flow rate of refrigerant delivered increases. Switching of the expansion valve 1 between the closed state and the open state is performed by the actuation rod 5 connected to the power element 8 via the stopper member 84.

In FIG. 1, the power element 8 is provided with a pressure operating chamber PO and a lower space LS partitioned by a diaphragm 83. Therefore, when the working gas in the pressure working chamber PO is liquefied, the diaphragm 83 and the stopper member 84 rise, and the working 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, so the operating rod 5 moves downward. In this way, the expansion valve 1 is switched between the open state and the closed state.

Furthermore, the lower space LS of the power element 8 communicates with the return flow path 23. Therefore, the volume of the working gas in the pressure working chamber PO changes depending on the temperature and pressure of the refrigerant flowing through the return passage 23, and the working rod 5 is driven. In other words, in the expansion valve 1 shown in FIG. be adjusted.

According to this embodiment, since the power element 8 is not downsized, there is no need to change the inner diameter of the receiving member 86, and the flow of the refrigerant flowing into the lower space LS from the return passage 23 does not change. It is possible to suppress the deterioration of the controllability of No. 3. Note that deterioration in controllability means that the actual value greatly exceeds the target value or that the actual value fluctuates upward or downward relative to the target value.

(Second embodiment)
FIG. 4 is an enlarged sectional view showing the vicinity of the power element of the expansion valve according to the second embodiment. FIG. 5 is a sectional view showing the power element 8A of this embodiment alone. This 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 of the embodiment described above, the same reference numerals are given and redundant explanation will be omitted.

A method of manufacturing the receiving member 86A will be explained. Similar to the embodiment described above, the first annular flange portion 86Aa, the first cylindrical portion 86Ab, the second annular flange portion 86Ac, and the second cylindrical portion 86Ad are formed by press-molding a metal plate material. do.

Further, after press forming, cutting is performed on the boundary between the second annular flange portion 86Ac and the second cylindrical portion 86Ad, which extend in directions orthogonal to each other, to form a reduced diameter portion 86Af. The outer diameter of the reduced diameter portion 86Af is smaller than the thread outer diameter of the male threaded portion 86Ae.

According to this embodiment, by forming the reduced diameter portion 86Af between the second annular flange portion 86Ac and the male threaded portion 86Ae, the reduced diameter portion 86Af is formed between the receiving member 86A and the seal recess 2c of the valve body 2. It is possible to secure an even larger seal space SP. Therefore, it is possible to employ a seal SL having a larger cross section, and the sealing performance and durability of the seal can be improved.

Note that the present invention is not limited to the above-described embodiments. Variations in any of the components of the embodiments described above are possible within the scope of the invention. Moreover, any component can be added or omitted in the embodiments described above.

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

Claims (7)

A power element including an upper lid member, a receiving member, and a diaphragm sandwiched between the upper lid member and the receiving member,
The receiving member is formed by press working, and has a cylindrical part and an annular flange part adjacent to the cylindrical part and extending in an outer circumferential direction of the cylindrical part,
The cylindrical portion includes a male threaded portion, and a portion of the cylindrical portion adjacent to the annular flange portion is cut to form a reduced diameter portion having an outer diameter smaller than the male threaded portion .
A power element characterized by: A power element including an upper lid member, a receiving member, and a diaphragm sandwiched between the upper lid member and the receiving member,
The receiving member is formed by press working, and has a cylindrical part and an annular flange part adjacent to the cylindrical part and extending in an outer circumferential direction of the cylindrical part,
The power element is attachable to the valve body,
A seal recess is formed in the valve body opposite to the annular flange,
A cutting process is performed on a portion of the cylindrical portion adjacent to the annular flange portion and radially aligned with the seal recess;
A power element characterized by: the cylindrical portion includes a male threaded portion;
The power element according to claim 2, characterized in that: The cutting process is performed in a range between the annular flange part and the male thread part,
The power element according to claim 1 or 3, characterized in that: The cylindrical portion is machined in parallel to the axis of the power element.
The power element according to any one of claims 1 to 4, characterized in that: The cylindrical portion and the annular flange portion are bent by press molding,
The power element according to any one of claims 1 to 5 , characterized in that: An expansion valve comprising the power element according to any one of claims 1 to 6 .

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