Directional control valve and method for assembling the same

Abstract

A main valve (10), comprising a first valve body (11) and a connecting pipe (12), the first valve body (11) having a first valve chamber, one end of the connecting pipe (12) and the first valve chamber communicating with each other; a main valve (10), comprising a second valve body (21) and a capillary tube (22), the second valve body (21) having a second valve chamber, a first end of the capillary tube (22) and the connecting pipe (12) or the first valve chamber communicating with each other, and a second end of the capillary tube (22) and the second valve chamber communicating with each other; a guide A directional control valve and an assembly method thereof, comprising: a valve (20); and a sleeve (30), in which a side wall of a connecting pipe (12) is provided with a first mounting hole communicating with an inner hole of the connecting pipe (12), a first valve body (11) is provided with a second mounting hole communicating with a first valve chamber, the sleeve (30) is inserted into the first mounting hole or the second mounting hole, and a first end of a capillary tube (22) is inserted into the sleeve (30). The directional control valve and the assembly method thereof are used to solve the problem that it is inconvenient to assemble the capillary tube of the guide valve to the main valve.

Description

[Technical field]

[0001] This application claims priority to the following patent applications: 1. Priority of the patent application filed with the State Intellectual Property Office of the People's Republic of China on March 1, 2021, bearing application number 202110225462.3 and entitled "Directional valve and method for assembling directional valve". 2. Priority of the patent application filed with the State Intellectual Property Office of the People's Republic of China on March 1, 2021, bearing application number 202120441908.1 and entitled "Directional valve".

[0002] The present application relates to the technical field of directional control valves, and more particularly to directional control valves and methods of assembling directional control valves. [Background technology]

[0003] The four-way valve includes a main valve and a guide valve, the D capillary of the guide valve is connected to the D connecting pipe of the main valve, the S capillary of the guide valve is connected to the S connecting pipe of the main valve, and the E capillary and C capillary of the guide valve are respectively connected to the valve chamber of the main valve and each other, and the working state of the main valve can be switched by using the guide valve.

[0004] In the related art, the capillary tube of the guide valve is inserted into the main valve and then directly connected to the main valve, which causes inconvenience in assembly. Summary of the Invention

[0005] The present application provides a directional control valve and an assembling method thereof to solve the problem that the capillary tube of the guide valve is inconvenient to assemble to the main valve in the related art.

[0006] According to one aspect of the present application, there is provided a directional control valve including: a main valve including a first valve body and a connecting pipe, where the first valve body has a first valve chamber, and one end of the connecting pipe and the first valve chamber are in communication with each other; a guide valve including a second valve body and a capillary tube, where the second valve body has a second valve chamber, and a first end of the capillary tube and the connecting pipe or the first valve chamber are in communication with each other, and a sleeve, where a first mounting hole is provided in a side wall of the connecting pipe and in communication with an inner hole of the connecting pipe, and a second mounting hole is provided in the first valve body and in communication with the first valve chamber, the sleeve is inserted into the first mounting hole or the second mounting hole, and a first end of the capillary tube is inserted into the sleeve.

[0007] When the technical aspects of the present application are applied, the directional control valve includes a main valve, a guide valve, and a sleeve. When assembling the capillary of the guide valve to the main valve, first, insert the sleeve into the first mounting hole of the connecting pipe or the second mounting hole of the first valve body, and after completing the connection between the sleeve and the connecting pipe or the first valve body, insert the first end of the capillary into the sleeve, and finally connect the capillary to the sleeve, thereby completing the assembly of the capillary to the main valve. By using the sleeve for transition, it is easy to assemble the capillary, and the assembly efficiency can be improved.

[0008] Furthermore, the connecting pipe and the sleeve are made of different materials, but the sleeve and the capillary tube are made of the same material. By using the sleeve to transition, the operation is easier than directly connecting the capillary tube to the connecting pipe.

[0009] In addition, the sleeve and the connecting pipe are welded together using a tunnel kiln, and / or the sleeve is made of copper and the connecting pipe is made of steel. After the connection between the sleeve and the connecting pipe is completed, the capillary tube is inserted into the sleeve and the capillary tube and the sleeve are welded together to complete the connection between the capillary tube and the connecting pipe, which is easy to assemble.

[0010] Furthermore, the capillary includes a body segment and a reduced diameter segment, the reduced diameter segment is located at a first end of the capillary and inserted into the sleeve, and an outer diameter of the body segment is larger than an aperture diameter of the sleeve. After the reduced diameter segment is inserted into the sleeve, the body segment can restrict the capillary from continuing to be inserted into the sleeve because the outer diameter of the body segment is larger than an aperture diameter of the sleeve. By controlling the length dimension of the reduced diameter segment, the dimension of the insertion depth of the capillary into the sleeve can be controlled.

[0011] Further, the connecting pipe includes an inlet pipe, an outlet pipe and a low pressure pipe, the capillary includes a first capillary and a second capillary, both ends of the first capillary communicate with the first valve chamber and the second valve chamber respectively, a first end of the second capillary communicates with the inlet pipe or the low pressure pipe, and a second end of the second capillary communicates with the second valve chamber. A guide valve can be used to control the working state of the main valve.

[0012] Furthermore, the end of the reduced diameter segment of the second capillary tube protrudes from the inner wall surface of the connecting pipe, and the distance between the end of the reduced diameter segment and the inner wall surface of the connecting pipe is L, which is 1 mm≦L≦3.5 mm. By setting this distance L within the above-mentioned range, it is possible to ensure a robust connection of the second capillary tube while avoiding the occurrence of the throttling phenomenon of the refrigerant. If the distance L is smaller than 1 mm, it is not possible to ensure a robust connection of the second capillary tube, and the welding material is likely to get into the second capillary tube. If the distance L is larger than 3.5 mm, the second capillary tube is inserted too deeply into the connecting pipe, causing the throttling phenomenon of the refrigerant and even causing a knocking noise.

[0013] Furthermore, the end of the narrowed segment of the first capillary is located outside the inner wall surface of the first valve body, or the end of the narrowed segment of the first capillary is aligned with the inner wall surface of the first valve body. A movable member is provided in the first valve chamber of the first valve body, and the above-mentioned structure can be used to avoid the narrowed segment of the first capillary from interfering with the movement of the movable member, thereby ensuring the normal operation of the device.

[0014] Furthermore, when the sleeve is inserted into the second mounting hole, an annular flange is provided on the outer wall of the first valve body, the annular flange is provided surrounding the outer periphery of the second mounting hole, and the sleeve is inserted into the annular flange. By reinforcing the sleeve using the annular flange, it is possible to ensure a strong connection between the sleeve and the first valve body, and to ensure a strong connection between the first capillary tube and the sleeve.

[0015] Furthermore, the main body segment has a first through hole, the reduced diameter segment has a second through hole, the first through hole and the second through hole communicate with each other, and the hole diameter of the first through hole and the hole diameter of the second through hole are equivalent. Since the hole diameter of the reduced diameter segment and the hole diameter of the main body segment are equivalent and the hole diameter of the reduced diameter segment is not reduced, the fluid resistance does not increase and the reduced diameter segment does not throttle the refrigerant.

[0016] In addition, the capillary tube further includes a transition segment, one end of the transition segment is connected to the body segment, and the other end of the transition segment is connected to the reduced diameter segment, and an outer diameter of the transition segment gradually increases in a direction toward the body segment. By providing the transition segment, processing of the reduced diameter segment is facilitated.

[0017] Additionally, the outer wall of the transition segment may be angled or curved.

[0018] Furthermore, the transition segment is located outside the opening of the sleeve such that when the reduced diameter segment is inserted into place, the transition segment and the opening of the sleeve come into abutment, limiting further insertion of the capillary tube.

[0019] In addition, there is a weld gap between the outer wall of the reduced diameter segment and the hole wall of the sleeve. When the reduced diameter segment and the sleeve are welded together, the weld material can fill the weld gap to complete a fixed connection between the capillary tube and the sleeve.

[0020] Furthermore, the directional control valve includes a four-way valve.

[0021] According to another aspect of the present application, there is provided a method for assembling the above-mentioned directional control valve, the method including a first step of inserting a sleeve into a first mounting hole or a second mounting hole, a second step of using a jig to bring an outer wall of the sleeve into close contact with a hole wall of the first mounting hole or the second mounting hole, a third step of using a tunnel kiln to weld the sleeve to a connecting pipe or a first valve body, and a fourth step of inserting a capillary into the sleeve, and welding the capillary to the sleeve when the capillary is inserted to a preset position. By using the sleeve for transition, it is easy to assemble the capillary, and the assembly efficiency can be improved. [Brief description of the drawings]

[0022] The drawings in the specification that form a part of this application are intended to provide a further understanding of the application, and the schematic examples and their explanations are intended to interpret the application and are not intended to unduly limit the application.

[0023] [Figure 1] 1 shows a structural schematic diagram of a directional control valve provided in an embodiment of the present application. [Diagram 2] 2 is a partially enlarged view of a portion A in FIG. 1. [Diagram 3] 1 shows a structural schematic diagram of a directional control valve provided in an embodiment of the present application. [Figure 4] The structural schematic diagram of the main valve in FIG. 1 is shown.

[0024] Here, the above mentioned drawings include the following reference numbers: 10 main valve, 11 first valve body, 12 connecting pipe, 121 inlet pipe, 122 outlet pipe, 123 low pressure pipe, 20 guide valve, 21 second valve body, 22 capillary tube, 221 main body segment, 222 reduced diameter segment, 223 first capillary tube, 224 second capillary tube, 30 sleeve, L distance between the end of the reduced diameter segment and the inner wall surface of the connecting pipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, the technical aspects of the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, but it is clear that the described embodiments are merely some of the embodiments of the present application, and are not all of the embodiments. The following description of at least one exemplary embodiment is actually merely explanatory, and does not impose any restrictions on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present application.

[0026] As shown in Figures 1 to 4, an embodiment of the present application provides a directional control valve including a main valve 10, a guide valve 20, and a sleeve 30. The main valve 10 includes a first valve body 11 and a connecting pipe 12, the first valve body 11 has a first valve chamber, and one end of the connecting pipe 12 and the first valve chamber communicate with each other. The guide valve 20 includes a second valve body 21 and a capillary tube 22, the second valve body 21 has a second valve chamber, a first end of the capillary tube 22 and the connecting pipe 12 or the first valve chamber communicate with each other, and a second end of the capillary tube 22 and the second valve chamber communicate with each other. In this embodiment, a first mounting hole communicating with the inner hole of the connecting pipe 12 is provided on the side wall of the connecting pipe 12, and a second mounting hole communicating with the first valve chamber is provided on the first valve body 11. The sleeve 30 is inserted into the first mounting hole or the second mounting hole, and the first end of the capillary tube 22 is inserted into the sleeve 30, thereby realizing communication between the first end of the capillary tube 22 and the connecting pipe 12 or the first valve chamber.

[0027] When the directional control valve provided in this embodiment is applied, when assembling the capillary tube 22 of the guide valve 20 to the main valve 10, first, insert the sleeve 30 into the first mounting hole of the connecting pipe 12 or the second mounting hole of the first valve body 11, and after completing the connection between the sleeve 30 and the connecting pipe 12 or the first valve body 11, insert the first end of the capillary tube 22 into the sleeve 30, and finally connect the capillary tube 22 to the sleeve 30, thereby completing the assembly of the capillary tube 22 to the main valve 10. By using the sleeve 30 for transition, it is easy to assemble the capillary tube 22, and the assembly efficiency can be improved.

[0028] In addition, the fact that one end of the connecting pipe 12 and the first valve chamber are in communication with each other means that one end of the connecting pipe 12 is connected to the first valve body 11, and the end of the connecting pipe 12 passes through the side wall of the first valve body 11 to be in communication with the first valve chamber.

[0029] Here, the connecting pipe 12 and the sleeve 30 are made of different materials, but the sleeve 30 and the capillary tube 22 are made of the same material. By using the sleeve 30 for the transition, the operation is easier than if the capillary tube 22 were directly connected to the connecting pipe 12.

[0030] In this embodiment, the sleeve 30 is made of copper material, the connecting pipe 12 is made of steel material, and the sleeve 30 and the connecting pipe 12 are welded together using a tunnel kiln. After the connection between the sleeve 30 and the connecting pipe 12 is completed, the capillary tube 22 is inserted into the sleeve 30, and the capillary tube 22 and the sleeve 30 are welded together to complete the connection between the capillary tube 22 and the connecting pipe 12, which is easy to assemble.

[0031] Specifically, the connection pipe 12 is made of a stainless steel material, and the sleeve 30 is made of a red copper material.

[0032] 2, the capillary tube 22 includes a body segment 221 and a reduced diameter segment 222, the reduced diameter segment 222 is located at a first end of the capillary tube 22 and inserted into the sleeve 30, and the outer diameter of the body segment 221 is larger than the hole diameter of the sleeve 30. After the reduced diameter segment 222 is inserted into the sleeve 30, the body segment 221 can restrict the capillary tube 22 from continuing to be inserted into the sleeve 30 because the outer diameter of the body segment 221 is larger than the hole diameter of the sleeve 30. By controlling the length dimension of the reduced diameter segment 222, the dimension of the insertion depth of the capillary tube 22 into the sleeve 30 can be controlled.

[0033] When assembling the sleeve 30 to the connecting pipe 12 or the first valve body 11, a jig can be used to control the insertion depth into the sleeve 30, and by combining the structure of the reduced diameter segment 222, the insertion depth of the capillary tube 22 into the connecting pipe 12 or the first valve body 11 can be limited.

[0034] Furthermore, if the capillary of the guide valve is inserted too deeply into the connecting pipe, the refrigerant will be squeezed when it flows through the cross section of the connecting pipe during the use of the air conditioner, and even a knocking sound will occur, which will affect the user's experience. In this embodiment, the engagement between the sleeve 30 and the reduced diameter segment 222 is utilized to limit the insertion depth of the capillary 22 into the connecting pipe 12, so that the refrigerant can be prevented from being squeezed, and the knocking sound will not occur, improving the user's experience.

[0035] The method of providing the reduced diameter segment 222 at the first end of the capillary tube 22 has the advantages of being simple in structure and easy to process, and can reduce processing costs and assembly costs.

[0036] 3, in this embodiment, the connecting pipe 12 includes an inlet pipe 121, an outlet pipe 122 and a low pressure pipe 123, the capillary tube 22 includes a first capillary tube 223 and a second capillary tube 224, both ends of the first capillary tube 223 communicate with the first valve chamber and the second valve chamber, a first end of the second capillary tube 224 communicates with the inlet pipe 121 or the low pressure pipe 123, and a second end of the second capillary tube 224 communicates with the second valve chamber. The guide valve 20 can be used to control the working state of the main valve 10.

[0037] As shown in FIG. 2, the end of the reduced diameter segment 222 of the second capillary tube 224 protrudes from the inner wall surface of the connecting pipe 12, and the distance between the end of the reduced diameter segment 222 and the inner wall surface of the connecting pipe 12 is L, which is 1 mm≦L≦3.5 mm. By setting this distance L within the above-mentioned range, it is possible to ensure a robust connection of the second capillary tube 224 while avoiding the occurrence of the throttling phenomenon of the refrigerant. If the distance L is smaller than 1 mm, the robust connection of the second capillary tube 224 cannot be ensured, and the welding material is likely to get into the second capillary tube 224. If the distance L is larger than 3.5 mm, the second capillary tube 224 is inserted too deeply into the connecting pipe 12, causing the throttling phenomenon of the refrigerant and even causing a knocking noise.

[0038] In this embodiment, an end of the sleeve 30 protrudes from the inner wall surface of the connecting pipe 12 , and an end of the reduced diameter segment 222 of the second capillary tube 224 protrudes from the end of the sleeve 30 .

[0039] In addition, when the end of the reduced diameter segment 222 protrudes from the inner wall surface of the connecting pipe 12, it means that the distance between the end of the reduced diameter segment 222 and the axis of the connecting pipe 12 is smaller than the distance between the inner wall surface of the connecting pipe 12 and the axis of the connecting pipe 12.

[0040] In this embodiment, the end of the narrowed segment 222 of the first capillary tube 223 is located outside the inner wall surface of the first valve body 11, or the end of the narrowed segment 222 of the first capillary tube 223 is flush with the inner wall surface of the first valve body 11. A movable member is provided in the first valve chamber of the first valve body 11, and the above-mentioned structure can be used to prevent the narrowed segment 222 of the first capillary tube 223 from interfering with the movement of the movable member, thereby ensuring the normal operation of the device.

[0041] In order to ensure the connection strength between the sleeve 30 and the first valve body 11, when the sleeve 30 is inserted into the second mounting hole, an annular flange is provided on the outer wall of the first valve body 11, the annular flange is provided surrounding the outer periphery of the second mounting hole, and the sleeve 30 is inserted into the annular flange.

[0042] Since the end of the reduced diameter segment 222 of the first capillary tube 223 is located outside the inner wall surface of the first valve body 11, or the end of the reduced diameter segment 222 of the first capillary tube 223 is aligned with the inner wall surface of the first valve body 11, the sleeve 30 can be reinforced using an annular flange to ensure a strong connection between the sleeve 30 and the first valve body 11, and the first capillary tube 223 and the sleeve 30 can be secured.

[0043] Here, main body segment 221 has a first through hole, reduced diameter segment 222 has a second through hole, the first through hole and the second through hole communicate with each other, and the hole diameter of the first through hole and the hole diameter of the second through hole are equal. Since the hole diameter of reduced diameter segment 222 and the hole diameter of main body segment 221 are equal, and the hole diameter of reduced diameter segment 222 is not reduced, the fluid resistance does not increase, and reduced diameter segment 222 does not throttle the refrigerant.

[0044] Specifically, the outer diameter of body segment 221 is greater than the outer diameter of reduced diameter segment 222 , and the inner diameter of body segment 221 is equal to the inner diameter of reduced diameter segment 222 .

[0045] In this embodiment, there is a weld gap between the outer wall of the reduced diameter segment 222 and the hole wall of the sleeve 30. When the reduced diameter segment 222 and the sleeve 30 are welded together, the weld gap can be filled with welding material to complete the fixed connection between the capillary tube 22 and the sleeve 30.

[0046] Here, the capillary tube 22 further includes a transition segment, one end of which is connected to the main body segment 221 and the other end of which is connected to the reduced diameter segment 222, and the outer diameter of the transition segment gradually increases in the direction toward the main body segment 221. Providing the transition segment makes it easy to process the reduced diameter segment 222. Here, the outer wall of the transition segment may be an inclined surface, which simplifies the structure. Alternatively, the outer wall of the transition segment may be a curved surface.

[0047] Specifically, the transition segment is located outside the mouth of the sleeve 30. When the reduced diameter segment 222 is inserted into place, the transition segment and the mouth of the sleeve 30 come into abutment with each other, limiting further insertion of the capillary tube 22.

[0048] In this embodiment, the directional control valve includes a four-way valve.

[0049] In this embodiment, the connecting pipe 12 includes two outlet pipes 122 , and the low pressure pipe 123 is located between the two outlet pipes 122 .

[0050] Another embodiment of the present application is a method for assembling the directional control valve provided above, comprising the steps of: A first step of inserting the sleeve 30 into the first mounting hole or the second mounting hole; a second step of bringing the outer wall of the sleeve 30 into close contact with the wall of the first mounting hole or the second mounting hole using a jig; A third step of welding the sleeve 30 and the connecting pipe 12 or the first valve body 11 using a tunnel kiln; a fourth step of inserting the capillary tube 22 into the sleeve 30, and welding the capillary tube 22 to the sleeve 30 when the capillary tube 22 is inserted to a preset position; The present invention provides a method for assembling a directional control valve, comprising:

[0051] In the second step, using a jig to bring the outer wall of sleeve 30 into tight contact with the hole wall of the first mounting hole or the second mounting hole specifically includes, when sleeve 30 is inserted into the first mounting hole or the second mounting hole, inserting the jig into the inner hole of sleeve 30 and using the jig to expand the diameter of sleeve 30 so that the outer wall of sleeve 30 is supported in tight contact with the hole wall of the first mounting hole or the second mounting hole, thereby achieving pre-fixing to sleeve 30.

[0052] Here, the jig works from the inside to the outside of the connection pipe 12, and does not destroy the diameter of the insertion port of the capillary tube.

[0053] In the fourth step, when the capillary tube 22 is inserted to a predetermined position, the capillary tube 22 and the sleeve 30 are welded together, specifically, after the reduced diameter segment 222 of the capillary tube 22 is inserted into the sleeve 30, as the reduced diameter segment 222 penetrates deeper, when the main body segment 221 and the tube mouth of the sleeve 30 abut each other, the main body segment 221 can restrict the capillary tube 22 from continuing to be inserted into the sleeve 30, at this time, the capillary tube 22 is inserted to a predetermined position, and then the capillary tube 22 and the sleeve 30 are welded together to complete the assembly.

[0054] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Those skilled in the art can make various modifications and variations to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application should be embraced within the protection scope of the present application.

Claims

1. A main valve (10) including a first valve body (11) and a connecting pipe (12), the first valve body (11) having a first valve chamber, one end of the connecting pipe (12) and the first valve chamber communicating with each other; a guide valve (20) including a second valve body (21) and a capillary tube (22), the second valve body (21) having a second valve chamber, a first end of the capillary tube (22) communicating with the connecting pipe (12) or the first valve chamber, and a second end of the capillary tube (22) communicating with the second valve chamber; a sleeve (30), in which a side wall of the connecting pipe (12) is provided with a first mounting hole communicating with an inner hole of the connecting pipe (12), and the first valve body (11) is provided with a second mounting hole communicating with the first valve chamber, the sleeve (30) is inserted into the first mounting hole or the second mounting hole, and a first end of the capillary tube (22) is inserted into the sleeve (30); Including, the capillary tube (22) includes a body segment (221) and a reduced diameter segment (222), the reduced diameter segment (222) is located at a first end of the capillary tube (22) and is inserted into the sleeve (30), the outer diameter of the body segment (221) is larger than the bore diameter of the sleeve (30); the connecting pipe (12) includes an inlet pipe (121) and a low pressure pipe (123), the capillary tube (22) includes a second capillary tube (224), a first end of the second capillary tube (224) communicates with the inlet pipe (121) or the low pressure pipe (123), and a second end of the second capillary tube (224) communicates with the second valve chamber; an end of the reduced diameter segment (222) of the second capillary tube (224) protrudes from an inner wall surface of the connecting pipe (12), and a distance L between the end of the reduced diameter segment (222) and the inner wall surface of the connecting pipe (12) is 1 mm≦L≦3.5 mm; Directional valve.

2. 2. The directional control valve according to claim 1, wherein the connecting pipe (12) and the sleeve (30) are made of different materials, and the sleeve (30) and the capillary tube (22) are made of the same material.

3. The sleeve (30) and the connecting pipe (12) are welded together using a tunnel kiln; and / or 2. The directional control valve according to claim 1, wherein the sleeve (30) is made of a copper material and the connecting pipe (12) is made of a steel material.

4. 2. The directional control valve according to claim 1, wherein the connecting pipe (12) includes an outlet pipe (122), and the capillary tube (22) includes a first capillary tube (223), both ends of which are mutually connected to the first valve chamber and the second valve chamber, respectively.

5. 5. The directional control valve according to claim 4, wherein an end of the reduced diameter segment (222) of the first capillary tube (223) is located outside the inner wall surface of the first valve body (11), or an end of the reduced diameter segment (222) of the first capillary tube (223) is aligned with the inner wall surface of the first valve body (11).

6. 2. The directional control valve according to claim 1, wherein when the sleeve (30) is inserted into the second mounting hole, an outer wall of the first valve body (11) is provided with an annular flange, the annular flange is provided surrounding an outer periphery of the second mounting hole, and the sleeve (30) is inserted into the annular flange.

7. 2. The directional control valve according to claim 1, wherein the main body segment (221) has a first through hole, the reduced diameter segment (222) has a second through hole, the first through hole and the second through hole communicate with each other, and a diameter of the first through hole and a diameter of the second through hole are equal to each other.

8. 2. The directional control valve of claim 1, wherein the capillary tube (22) further comprises a transition segment, one end of the transition segment being connected to the body segment (221) and the other end of the transition segment being connected to the reduced diameter segment (222), and an outer diameter of the transition segment gradually increases in a direction toward the body segment (221).

9. The directional control valve according to claim 8 , wherein an outer wall of the transition segment is an inclined surface or a curved surface.

10. The directional control valve of claim 8, wherein the transition segment is located outside the orifice of the sleeve (30).

11. 2. The directional control valve according to claim 1, wherein a weld gap is provided between an outer wall of the reduced diameter segment (222) and a wall of the bore of the sleeve (30).

12. The directional control valve according to claim 1 , wherein the directional control valve comprises a four-way valve.

13. A method for assembling the directional control valve according to any one of claims 1 to 12, comprising the steps of: A first step of inserting a sleeve (30) into the first mounting hole or the second mounting hole; a second step of bringing an outer wall of the sleeve (30) into close contact with a wall of the first mounting hole or the second mounting hole using a jig; a third step of welding the sleeve (30) to the connecting pipe (12) or the first valve body (11) using a tunnel kiln; a fourth step of inserting a capillary tube (22) into the sleeve (30) and, when the capillary tube (22) is inserted to a preset position, welding the capillary tube (22) to the sleeve (30); A method for assembling a directional control valve comprising:

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