JP2022091885A - Electronic expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic expansion valve capable of releasing a pressure in a communication hole in controlling a large flow volume in a first valve port on a valve body, so that a pressure difference of a chamber in the valve body can be balanced, drive torque of the electronic expansion valve can be secured, and miniaturization of a valve body structure can be realized.

SOLUTION: An electronic expansion valve includes a valve body (10) and a valve head (20) provided in the valve body. The valve body has a valve chamber (100) and a first valve port (11) communicating with the valve chamber. The valve head is provided in the valve chamber, and is used to control the first valve port on the valve body to open or close. The valve head has a second valve port communicated with the first valve port. A spindle (30) is provided in the second valve port of the valve head to control the second valve port on the valve head to open or close. The spindle is provided with a communication hole communicated upward from a bottom portion of the spindle to a valve chamber part positioned above the valve head.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

[001] This application is filed on February 11, 2018 with application number 201820124945.1, named "two-stage electronic expansion valve", and filed on December 7, 2018 with application number 201822057842. Claims the priority of the Chinese patent application, which is 0.7 and is named "Electronic Expansion Valve", the full text of which is incorporated herein by reference.

[002] The present application relates to the technical field relating to solenoid valves, and particularly to solenoid expansion valves.

[003] The electronic expansion valve is a promising automatic adjustment component that meets the demands of the development of freezing and electrical integration as a component that regulates the flow rate and provides conditions for the intelligent refrigeration system. The electronic expansion valve uses the principle of the stepping motor to drive the magnetic rotor member by a coil and rotate it in the forward and reverse directions, and convert the rotational operation of the magnetic rotor member into the vertical movement of the push rod. , The spindle connected to it is moved to move up or down to control the flow rate of the refrigerant.

[004] Here, the generally used electronic expansion valve usually has two valve openings for liquid flow, each of which is controlled by a valve head, and is a first type installed in a valve body. It is a second valve port installed in the valve head that controls opening and closing having a valve port and a spindle provided in the valve head, and realizes two-step flow rate adjustment. The spindle realizes precise control of the flow rate of the electronic expansion valve by controlling the opening and closing of the second valve port, and the valve head controls the opening and closing of the second valve port to control the large flow rate of the electronic expansion valve in the fully open state. It can be understood that a large opening is secured.

[005] In the conventional electronic expansion valve, when the first valve port on the valve body is opened to realize a large flow rate communication at the time of operation, a differential pressure is formed on the inlet / outlet side on the valve body. Since the diameter of the second valve opening on the valve head is generally 2.0 mm or less, and the diameter of the first valve port on the valve body is generally 8.0 mm or more, the electronic expansion valve of this electronic expansion valve. It is difficult to secure the requirement for the CV value at full throttle.

[006] In view of this, it is necessary to provide an electronic expansion valve.

[007] The electronic expansion valve of the present application includes a valve body and a valve head provided in the valve body, and the valve body has a valve chamber and a first valve opening communicated with the valve chamber. , The valve head is installed in the valve chamber and is used to control the opening and closing of the first valve opening on the valve body, and the valve head has a second valve opening communicated with the first valve opening. An electronic expansion valve in which a spindle for controlling the opening and closing of the second valve opening on the valve head is installed in the second valve opening of the valve head, and the spindle is connected to the spindle from the bottom of the spindle from the valve head. A passage hole is installed that communicates upward to the valve chamber portion located above.

[008] Further, the valve head is provided with a valve hole in the axial direction, the valve hole penetrates the valve head and communicates with the second valve port, and the valve head is radially above the second valve port. A flow path hole is opened in the valve hole, and the flow path hole communicates with the valve hole and the valve chamber, respectively.

[009] Further, in the valve head, a step is installed on the hole wall of the valve hole, a flange is installed on the spindle, and the flange is installed facing the step.

[010] Further, the flow path hole includes an axial hole provided below the flange and a radial hole provided above the flange, and the axial hole communicates with the radial hole.

[011] Further, the spindle is fitted with a second seal ring for seal engagement with the inner wall of the valve hole of the valve head in the lower portion of the flange.

[012] Further, a seal portion is installed on the valve head, a seal engagement portion is installed on the valve body at the position of the first valve port, and the spindle seals the first valve port on the valve body. In addition, the seal portion on the valve head can be moved so as to abut on the seal engagement portion on the valve body.

[013] Further, the seal portion is a gasket fixed to the end surface of the valve head on the valve body on the side facing the first valve opening, and the seal engagement portion is installed so as to surround the first valve opening. It is a convex column, and the gasket can be sealed and engaged with the convex column.

[014] Further, the gasket is a polytetrafluoroethylene gasket.

[015] Further, the gasket is engaged with the end surface of the valve head on the valve body on the side facing the first valve port, and the position is limited and fixed by the stopper.

[016] Further, the electronic expansion valve further includes a core shaft screw that partially extends into the valve head, the core shaft screw pushing the spindle downward so as to move downward along the axial direction of the valve head. The valve head can be moved upward so as to move away from the first valve opening.

[017] Further, the core shaft screw has a contact portion fixed to the end surface on the side facing the spindle, and a contact engagement portion is provided on the spindle to contact the contact portion when the core shaft screw moves downward. It can be moved to contact engage and the spindle screw can be pushed out at the contact so as to move the spindle towards the second valve opening on the valve head.

[018] Further, the contact portion is a steel ball fixed to the core shaft screw, and the contact engagement portion is an arc-shaped groove that engages with the steel ball.

Further, the valve head is provided with a pressing sleeve having a through hole, and the core shaft screw penetrates the through hole on the pressing sleeve and extends into the valve head, where the core shaft screw is used. The outer diameter of the end of the valve head extending into the valve head is larger than the diameter of the through hole on the pressing sleeve.

[020] Further, a guide sleeve is installed on the valve body, and a part of the valve head extends upward into the guide sleeve and is slidably connected to the guide sleeve.

[021] Further, a first seal ring for seal engagement with the guide sleeve is adjusted to a portion of the valve head extending into the guide sleeve.

Further, a muffling block is installed in the valve head, and the muffling block is installed in the passage where the second valve port and the first valve port are communicated with each other.

[023] Further, the diameter of the first valve opening on the valve body is 10 mm or more.

[024] The electronic expansion valve provided in the present application is a flow hole when the electronic expansion valve controls a large flow rate at the first valve port on the valve body through the structural design of the flow hole on the spindle. This makes it possible to balance the differential pressure of the chamber inside the valve, secure the drive torque of this electronic expansion valve, and realize the miniaturization of the valve body structure.

[025] FIG. 6 is a structural conceptual diagram of an electronic expansion valve provided in the first embodiment of the present application. [026] FIG. 1 is an assembly conceptual diagram of a valve head, a spindle, and a core shaft screw of the electronic expansion valve in FIG. 1. [027] Another angle view of the valve head of the electronic expansion valve in FIG. 1. [028] Another angle view of the spindle of the electronic expansion valve in FIG. 1. [029] It is a structural conceptual diagram of the core shaft screw of the electronic expansion valve in FIG. 1. [030] FIG. 3 is a structural conceptual diagram of an electronic expansion valve provided in a second embodiment of the present application.

[033] Hereinafter, the technical aspects of the embodiments of the present application will be clearly and completely described, but it is clear that the described embodiments are merely partial embodiments of the present application and not all embodiments. Is. All other embodiments acquired by those skilled in the art on the premise that they do not engage in creative labor, based on the embodiments in this application, all fall within the scope of protection of this application.

[034] Referring to FIGS. 1 and 2, the electronic expansion valve provided in the first embodiment of the present application includes a valve body 10, a valve head 20, a spindle 30, a core shaft screw 40, and a guide sleeve 50. A first valve port 11 is installed in the valve body 10, a second valve port 21 communicated with the first valve port 11 is installed in the valve head 20, and the valve head 20 is a valve. It can engage with the body 10 to realize opening / closing control for the first valve opening 11 on the valve body 10, and the spindle 30 can perform opening / closing control for the second valve opening 21 on the valve head 20. can.

[035] The valve chamber 100 is formed inward in the valve body 10, a connection port 12 is further installed in the valve body 10, and the first valve port 11 and the connection port 12 communicate with the valve chamber 100, respectively. Will be done.

[036] In the present embodiment, the first valve port 11 is installed on the bottom wall 16 of the valve body 10, the first connection pipe 13 is connected to the position of the first valve port 11, and the connection port 12 is connected. , The second connection pipe 14 is connected to the position of the connection port 12 installed on the side wall of the valve body 10, and the first connection pipe 13 and the second connection pipe 14 are used for connection with the external pipeline. As a result, communication between this electronic expansion valve and the external pipeline is realized.

[037] The valve head 20 is installed in the valve chamber 100 of the valve body 10 and can move with respect to the valve body 10 along the axial direction of the valve body 10, whereby the valve head 20 and the valve body 10 can be moved. Engagement with the first valve port 11 on the valve body 10 is controlled to open and close.

[038] Further referring to FIG. 3, the valve head 20 is provided with a valve hole 200 penetrating the valve head 20 in the axial direction, and the second valve port 21 is communicated with the valve hole 200 so that the valve head 20 is communicated with the valve head 20. A flow path hole 22 is opened above the second valve port 21 along the radial direction of the valve head 20, and the flow path hole 22 communicates with the valve hole 200 and the valve chamber 100.

[039] In the present embodiment, the valve head 20 is provided with the seal portion 23, the valve body 10 is provided with the seal engaging portion 15, and the seal engaging portion 15 is the first on the valve body 10. The seal portion 23 on the valve head 20 abuts on the seal engaging portion 15 on the valve body 10 in order to seal the first valve port 11 on the valve body 10. It can be engaged, which ensures the stability of the seal to the first valve opening on the valve body when the valve head and valve body engage with each other. That is, the opening and closing of the first valve opening 11 of the valve body 10 in the electronic expansion valve of the present embodiment is controlled by the seal portion 23 on the valve head 20 and the seal engaging portion 15 on the valve body 10.

[040] Specifically, the seal portion 23 is a gasket fixed to the end surface of the valve head 20 on the valve body 10 on the side facing the first valve port 11, and the seal engaging portion 15 is a first. It is a convex column installed surrounding the valve port 11 of 1, and the valve head 20 can move the gasket downward to move the gasket downward so as to be seal-engaged with the convex column, whereby on the valve body 10. A seal of the first valve port 11 is realized. Here, the gasket is engaged to the end surface of the valve head 20 on the valve body 10 on the side facing the first valve port 11, and is fixed as a stopper by the stopper 24. In the present embodiment, the stopper 24 and the valve head 20 are fixed. Specifically, the stopper 24 can be fixed by welding, and the stopper 24 is installed flush with the end surface of the valve head 20 on the valve body 10 on the side facing the first valve port 11.

[041] Here, the convex column is installed on the bottom wall 16 of the valve body 10 to facilitate the realization of a seal to the first valve port 11 by engaging with the gasket on the valve head 20 and the bottom. A part of the wall 16 is raised upward. In the present embodiment, the bottom wall and the valve body 10 have a separate structure, and it is preferable to fix the valve body 10 by press fitting and welding in order to facilitate production control of the entire valve body 10. The seal portion 23 and the seal engaging portion 15 are not limited to the gasket and the convex column shown in the drawing, and those skilled in the art install the seal portion 23 as a gasket as needed, and the gasket is a valve body on the valve head 20. A gasket can be installed so as to surround the first valve opening 11 on the valve body 10 so as to project outward with respect to the end face portion on the side facing the first valve opening 11 on the valve body 10. Therefore, it can be understood that the seal engaging portion 15 is the bottom wall 16 on the valve body 10. Alternatively, the seal portion 23 is a convex pillar, and the seal engaging portion 15 is a gasket that engages with the convex pillar.

[042] Further, the material of the gasket has a certain degree of flexibility and elasticity, and when the gasket and the convex column interact with each other, the gasket undergoes some deformation due to the extrusion of the convex column, which causes the convex column. When the gasket and the gasket are engaged with each other, the sealing property between the intersecting surfaces of the two is improved, and the sealing with respect to the first valve port 11 is further secured. In the present embodiment, the gasket is a polytetrafluoroethylene seal, that is, the material of the gasket of the present embodiment is polytetrafluoroethylene, but of course, the material of the gasket for which the protection of the present application is sought is polytetrafluoroethylene. Other materials having flexibility and elasticity may be selected and used without limitation.

[043] The spindle 30 is installed in the valve head 20 and can move along the axial direction of the valve head 20 in order to control the opening and closing of the valve head 20 with respect to the second valve port 21.

[044] The spindle 30 is provided with a flow hole 300 that is vertically communicated from the bottom of the spindle 30 to the valve chamber 100 portion located above the valve head 20, so that the valve body 10 on the electronic expansion valve 10 is provided. When the first valve port 11 of the above is opened to realize a large flow rate communication, the electronic expansion valve in the present implementation state can be depressurized at the flow hole 300 on the spindle 30, whereby the valve body 10 can be depressurized. The differential pressure of the chamber 100 inside is balanced, and the differential pressure between the first valve port 11 and the connection port 12 of the valve body 10 is balanced, and the differential pressure balance on the inlet / outlet side on the valve body is realized. It is possible to secure the drive torque of this electronic expansion valve and to reduce the size of the valve body structure.

[045] Specifically, the flow hole 300 on the spindle 30 includes an axial hole 301 provided below the flange 31 and a radial hole 302 provided above the flange 31, and the axial hole 301. And the radial hole 302 communicate with each other.

[046] Further referring to FIG. 4, one step 25 installed above the flow hole 22 is installed on the hole wall of the valve hole 200 on the valve head 20, and a flange 31 is installed on the spindle 30. The step 25 on the valve head 20 and the flange 31 on the spindle 30 are installed facing each other, and the spindle 30 is moved between the step 25 and the flange 31 in a direction away from the second valve opening 21. The preload spring 101 provided in the above is installed.

[047] The core shaft screw 40 is partially extended into the valve head, and the core shaft screw 40 can push the spindle 30 downward so as to move downward along the axial direction of the valve head 20. The valve head 20 can be moved upward so as to move away from the first valve opening 11.

[048] In the present embodiment, the core shaft screw 40 and the spindle 30 are installed separately, and with reference to FIG. 5, the contact portion 41 is fixed to the end surface of the core shaft screw 40 on the side facing the spindle. A contact engaging portion 32 for abutting against the contact portion 41 is provided on the end surface of the spindle 30, and the core shaft screw 40 moves downward to move the contact portion 41 into the contact engaging portion 32 of the spindle 30. It can be moved to insert and the contact portion 41 can push the spindle 30 out so as to move in the direction of the second valve opening 21 on the valve head 20. That is, when the core shaft screw 40 pushes the spindle 30 downward, the contact portion 41 fixed to the core shaft screw 40 first engages with the contact engagement portion 32 provided on the spindle 30, and then the contact portion 41 The contact engaging portion 32 is pushed up, thereby realizing a downward drive of the core shaft screw 40 with respect to the spindle 30.

[049] In the electronic expansion valve of the present embodiment, the spindle 30 is driven downward by the core shaft screw 40 so as to move, and the contact engagement portion on the spindle 30 is first passed through the contact portion 41 fixed to the core shaft screw 40. After contact-engaging with 32, the contact portion 41 drives the spindle 30 downward through the contact engagement portion 32, whereby the coaxiality between the core shaft screw 40 and the spindle 30 is ensured, and the spindle 30 is further driven. It can be understood that when moving in the valve head 20, it plays a role in lowering the probability of locking. This is because, in the prior art, the core shaft screw and the spindle are specifically integrally connected by crimping and welding, the temperature during welding is high, the core shaft screw is easily deformed, and the core shaft screw 40 and the spindle 30 are connected. This is because the coaxiality between and is deteriorated.

[050] Specifically, the contact portion 41 is installed as a steel ball, and accordingly, the contact engaging portion 32 on the spindle 30 is installed as an arc groove, and the steel ball engages with the arc groove. It can be understood that when the steel ball is contact-engaged with the arcuate groove, the connection area between the two is large, and the stability when the two interact with each other after contact is enhanced. Of course, the contact portion 41 and the contact engagement portion 32 are not limited to the steel ball and the arcuate groove shown in the drawing, and those skilled in the art contact the contact portion 41 with the contact engagement portion 32 as necessary. The end face to be engaged may have an arc-shaped structure, or the contact portion 41 may have a structure of another shape, and the steel ball and the arc-shaped groove may be switched, that is, the core shaft screw 40 may be attached to the spindle 30. An arcuate groove is installed on the end face on the facing side, and a steel ball is correspondingly installed on the spindle 30.

[051] Here, the steel ball is fixed to the central axis of the core shaft screw 40 by welding, and it is preferable to use a spot welding method, and the arc groove is opened in the central axis of the spindle 30.

[052] In the present embodiment, the valve head 20 is provided with a pressing sleeve 26 having a through hole 261, and the core shaft screw 40 penetrates the through hole 261 on the pressing sleeve 26 and is inside the valve head 20. Here, the outer diameter of the end portion of the core shaft screw 40 extending into the valve head 20 is larger than the hole diameter of the through hole 261 on the pressing sleeve 26. When the core shaft screw 40 moves upward, the end portion having a large outer diameter on the core shaft screw 40 can be locked to the pressing sleeve 26 on the valve head 20, and the core shaft screw 40 moves further upward. If so, the valve head 20 can be moved so as to move away from the first valve opening 11.

[053] It is understood from the above that the core shaft screw 40 moves downward and pushes out the spindle 30 through the steel ball 41 fixed to the core shaft screw 40 along the axial direction of the valve head 20. When moving in the direction of the second valve opening 21 on the valve head 20, the flange 31 on the spindle 30 compresses the preload spring 101, and in this process, the step 25 on the valve head 20 points downward on the preload spring 101. The first valve opening 11 on the valve body 10 until the seal portion 23 on the valve head 20 abuts and engages with the seal engaging portion 15 on the valve body 10 by pushing up the valve head 20. Moved in the direction, thereby achieving closure of the first valve port 11 on the valve body 10 on the valve head 20, after which the spindle 30 has the spindle 30 on the valve head 20 and the second valve port. The preload spring 101 is continuously compressed until it is inserted into 21, and the second valve opening 21 on the valve head 20 is closed. That is, the electronic expansion valve of the present embodiment first seals the first valve opening 11 on the valve body 10 and then seals the second valve opening 21 on the valve head 20 at the time of operation. When the core shaft screw 40 moves upward, after the core shaft screw 40 is separated from the spindle 30, the spindle 30 is driven by the elastic return of the preload spring 101, and the spindle 30 is first driven by the second valve on the valve head 20. The core shaft screw 40 continuously moves upward to realize the opening of the second valve port 21 by pushing it upward so as to be separated from the mouth 21, and the core shaft screw 40 pushes the valve head 20 through the pressing sleeve 26. It can be moved upward so as to move away from the first valve opening 11 on the valve body 10, and the opening of the first valve opening 11 on the valve body 10 is realized.

[054] The guide sleeve 50 is installed above the valve chamber of the valve body 10 and is fixedly connected to the valve body 10. Here, a part of the valve head 20 for guiding the movement of the valve head 20 in the valve chamber of the valve body 10 extends upward into the guide sleeve 50 and is slidably connected to the guide sleeve 50. The coaxiality between the valve head 20, the core shaft screw 40, and the spindle 30 was secured.

[055] In the present embodiment, a first seal ring 102 for sealing engagement with the guide sleeve 50 is fitted to a portion of the valve head 20 extending into the guide sleeve 50, whereby the valve body 10 is fitted with a first seal ring 102. A second seal ring 102 for seal engagement with the inner wall of the valve hole 200 of the valve head 20 is fitted to the lower portion of the flange 31 of the spindle 30 to ensure the sealing property of the valve chamber 100. This ensures the sealing performance of the spindle 30 with respect to the second valve opening 21 on the valve head 20.

[056] A person skilled in the art will specifically design the valve head 20, the size of the spindle 30, and the diameters of the first valve port 11 and the second valve port 21 according to the flow rate needs of this electronic expansion valve. Can be understood. In the present embodiment, the diameter of the first valve port 11 is 10 mm or more. When the diameter of the first valve port 11 is less than 10 mm, and thus even smaller, the vertical differential pressure of the spindle 30 is not sufficiently remarkable, and from the viewpoint of simplifying the structure, the first valve port 300 is not installed. The diameter of the valve port 11 can be 10 mm or more, and the performance of the electronic expansion valve can be ensured in order to secure the requirement for the CV value of the valve head 20 after the first valve port 11 on the valve body 10 is opened. The merit of this embodiment of eliminating the influence of the differential pressure can be exhibited.

[057] Referring to FIG. 6, the electronic expansion valve provided in the second embodiment of the present application includes a valve body 1, a valve head 2, a spindle 3, a core shaft screw 4, and a guide sleeve 5. A first valve port 6 is installed in the body 1, a second valve port 7 communicated with the first valve port 6 is installed in the valve head 2, and the valve head 2 is engaged with the valve body 1. In combination, the opening / closing control of the first valve opening 6 on the valve body 1 can be realized, and the spindle 3 can perform the opening / closing control of the second valve opening 7 on the valve head 2.

[058] Compared to the electronic expansion valve provided in the first embodiment of the present application, the electronic expansion valve provided in the second embodiment of the present application has almost the same configuration and operating principle. The valve head 2 and the spindle 3 on the electronic expansion valve are mainly different in that a part thereof extends into the guide sleeve 5 and is slidably connected to the guide sleeve 5. The drive member 8 for driving the spindle 3 on the electronic expansion valve includes a coil portion, a sleeve, a rotor, a guide plate, a nut, a stopper spring, and the like, and the specific configuration and principle are the electronic expansion valve in the prior art. The configuration and principle of the drive member are the same, that is, the spindle 3 in the present embodiment is fixedly connected to the core shaft screw 4 that moves and moves the spindle 3, and the valve head 2 and the valve body on the electronic expansion valve are fixedly connected. The seal with 1 is a hard fit, and the valve head 2 engages with the first valve opening 6 of the valve body 1 to realize a seal with respect to the first valve opening 6 on the valve body 1.

[059] Those skilled in the art can easily understand that each of the above preferred embodiments can be freely combined and added on a consistent premise.

[060] The embodiments described above are merely exemplary and not limiting, and various obvious or equivalents made by one of ordinary skill in the art for the above details, as long as they do not deviate from the basic principles of the present application. It should be understood that any modification or replacement of is included in the claims of this application.

[031] In the first embodiment, 10, valve body, 11, first valve port, 12, connection port, 13, first connection pipe, 14, second connection pipe, 15, seal engaging portion. , 16, bottom wall, 20, valve head, 21, second valve port, 22, flow path hole, 23, seal part, 24, stopper, 25, step, 26, pressing sleeve, 30, spindle, 31, flange. , 32, contact engagement part, 40, core shaft screw, 41, contact part, 50, guide sleeve, 100, valve chamber, 101, preload spring, 102, first seal ring, 103, second seal ring, 200, valve hole, 261, through hole, 300, flow hole, 301, axial hole, 302, radial hole.

[032] In the second embodiment, 1, valve body 2, valve head 3, spindle 4, core shaft screw 5, guide sleeve, 6, first valve port, 7, second valve port. , 8, drive member.

[044] The valve body 10 on the electronic expansion valve is provided with a flow hole 300 that is vertically communicated from the bottom of the spindle 30 to the valve chamber 100 portion located above the valve head 20 in the spindle 30. When the first valve port 11 of the above is opened to realize a large flow rate communication, the electronic expansion valve in the present implementation state can be depressurized at the flow hole 300 on the spindle 30, whereby the valve body 10 can be depressurized. The differential pressure of the valve chamber 100 inside is balanced, and the differential pressure between the first valve port 11 and the connection port 12 of the valve body 10 is balanced to realize the differential pressure balance on the inlet / outlet side on the valve body. However, it is possible to secure the drive torque of the electronic expansion valve and to reduce the size of the valve body structure.

[046] Further referring to FIG. 4, one step 25 installed above the flow path hole 22 is installed in the hole wall of the valve hole 200 on the valve head 20, and the spindle 30 has a flange 31. The step 25 on the valve head 20 and the flange 31 on the spindle 30 are installed so as to face each other, and the spindle 30 is moved between the step 25 and the flange 31 in a direction away from the second valve opening 21. The preload spring 101 is installed.

Claims (17)

The valve body includes a valve body and a valve head provided in the valve body, the valve body has a valve chamber and a first valve opening communicating with the valve chamber, and the valve head is the valve. It is installed indoors and used to control the opening and closing of the first valve port on the valve body, and the valve head has a second valve port communicated with the first valve port, and the valve head has the same. An electronic expansion valve in which a spindle for controlling the opening and closing of the second valve opening on the valve head is installed in the second valve opening of the valve head, and the spindle is connected to the spindle from the bottom of the spindle. An electronic expansion valve provided with a passage hole that communicates upward to the valve chamber portion located above the valve head. The valve head has a valve hole formed in the axial direction, the valve hole penetrates the valve head and communicates with the second valve port, and the valve head has a diameter above the second valve port. The electronic expansion valve according to claim 1, wherein a flow path hole is opened in the direction, and the flow path hole communicates with the valve hole and the valve chamber, respectively. The electronic expansion valve according to claim 2, wherein the valve head is provided with a step on the hole wall of the valve hole, a flange is installed on the spindle, and the flange is installed facing the step. .. 3. The flow path hole includes an axial hole provided below the flange and a radial hole provided above the flange, and the axial hole communicates with the radial hole. The electronic expansion valve described in. The electronic expansion valve according to claim 3, wherein the spindle is fitted with a second seal ring for seal engagement with the valve hole inner wall of the valve head in a lower portion of the flange. A seal portion is installed on the valve head, a seal engaging portion is installed on the valve body at the position of the first valve port, and the spindle seals the first valve port on the valve body. The electronic expansion valve according to claim 1, wherein the seal portion on the valve head can be moved so as to abut on the seal engaging portion on the valve body. The seal portion is a gasket fixed to the end surface of the valve head on the valve body on the side facing the first valve opening, and the seal engaging portion is installed so as to surround the first valve opening. The electronic expansion valve according to claim 6, wherein the gasket is a convex column, and the gasket can be hermetically engaged with the convex column. The electronic expansion valve according to claim 7, wherein the gasket is a polytetrafluoroethylene gasket. The electronic expansion valve according to claim 7, wherein the gasket is engaged with an end surface of the valve head on the valve body on the side facing the first valve port, and is position-controlled and fixed by a stopper. The core shaft screw further includes a core shaft screw that partially extends into the valve head, and the core shaft screw can push the spindle downward so as to move downward along the axial direction of the valve head. The electronic expansion valve according to claim 1, wherein the head can be moved upward so as to move away from the first valve opening. The core shaft screw has a contact portion fixed to the end surface on the side facing the spindle, a contact engagement portion is installed on the spindle, and when the core shaft screw moves downward, the contact portion is moved to the contact portion. The core shaft screw can be moved so as to be in contact engagement with the contact engagement portion, and the spindle can be pushed out at the contact portion so as to move the spindle toward the second valve opening on the valve head. The electronic expansion valve according to claim 10. The electronic expansion valve according to claim 11, wherein the contact portion is a steel ball fixed to the core shaft screw, and the contact engagement portion is an arc-shaped groove that engages with the steel ball. A pressing sleeve having a through hole is installed in the valve head, and the core shaft screw penetrates the through hole on the pressing sleeve and extends into the valve head, where the core shaft screw is used. The electronic expansion valve according to claim 10, wherein the outer diameter of the end portion of the valve head extending into the valve head is larger than the diameter of the through hole on the pressing sleeve. The electronic expansion valve according to claim 1, wherein a guide sleeve is installed in the valve body, and a part of the valve head extends upward into the guide sleeve and is slidably connected to the guide sleeve. The electronic expansion valve according to claim 14, wherein a first seal ring for sealing engagement with the guide sleeve is adjusted to a portion of the valve head extending into the guide sleeve. The electronic expansion according to claim 1, wherein a muffling block is installed in the valve head, and the muffling block is installed in a passage in which the second valve port and the first valve port are communicated with each other. valve. The electronic expansion valve according to claim 1, wherein the diameter of the first valve port on the valve body is 10 mm or more.

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