Motorized valve

Abstract

The present application provides an electric valve, which improves the action when opening the valve. The electric valve (1) comprises: a valve shaft (10) provided with a valve core (14); a valve body (40) provided with a valve seat portion (46a) which is in contact with the valve core (14) or away from the valve core, a valve port hole (46) and a valve chamber (40a) for guiding fluid in and out; a lifting mechanism for lifting the valve shaft relative to the valve seat portion; a lower stop mechanism (29) for limiting the downward movement of the valve shaft (10), the valve core (14) is guided by the valve port hole (46) at least when closing the valve, during the valve opening action, the valve shaft (10) is not guided by the body guide portion (43) provided on the valve body (40), when the valve core (14) is guided by the valve port hole (46), the valve shaft is guided by the body guide portion (43).

Description

Technical Field

[0001] This invention relates to an electric valve used as a flow control valve in the refrigeration cycle of an air conditioner, refrigeration unit, etc. Background Technology

[0002] As such an electric valve, a known structure includes the following components: a valve shaft with a valve core; a valve body with a valve port and a valve chamber for fluid introduction and discharge, the valve port having a valve seat portion that contacts and separates from or approaches the valve core; a motor with a rotor connected to the valve shaft and a stator for rotating the rotor; a threaded feed mechanism consisting of a fixed thread portion on the valve body side and a movable thread portion on the valve shaft side, for driving the valve core of the valve shaft to rise and fall relative to the valve seat portion of the valve body according to the rotation of the rotor; and a lower stop mechanism for restricting the downward rotation of the valve shaft (see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-180525

[0006] The technical problem that the invention aims to solve

[0007] However, in the previous design, when the valve was closed, the valve port, the main guide component consisting of the through hole of the valve body, and the guide bushing fixed to the valve body with a fixed thread on the outer periphery interfered with the valve shaft. As a result, the sliding resistance increased when the valve was opened, which became the reason for the reduced operability. Summary of the Invention

[0008] The purpose of this invention is to provide an electric valve that improves the actuation of the valve during opening.

[0009] Technical means for solving technical problems

[0010] To address the aforementioned issues, the electric valve of the present invention comprises: a valve shaft having a valve core; a valve body having a valve port and forming a valve chamber for fluid introduction and discharge, the valve port having a valve seat portion that contacts or separates from the valve core; a motor having a rotor connected to the valve shaft and a stator for rotating the rotor; and a threaded feed mechanism having a fixed threaded portion for a guide bushing provided on the valve body side and a movable threaded portion provided on the valve shaft side, for adjusting the feed according to the valve core's position on the valve shaft. Driven by the rotation of the rotor, the valve core of the valve shaft is raised and lowered relative to the valve seat portion of the valve body; and a lower stop mechanism is provided to restrict the downward rotational movement of the valve shaft. The valve core is guided by the valve port orifice at least when the valve is closed. During the period when the valve core is guided by the valve port orifice during the valve closing and opening operations, the valve shaft is not guided by the main body guide portion of the valve body. When the valve port orifice releases the guidance of the valve core during the opening operation, the valve shaft is guided by the main body guide portion.

[0011] In this electric valve, during the period when the valve core is guided by the valve orifice during valve closure and valve opening, the valve shaft is not guided by the main body guide, thus suppressing interference between the valve shaft and the main body guide. Therefore, compared to the case where the valve shaft is always guided by the main body guide during valve closure and valve opening, the sliding resistance during valve opening is reduced, resulting in better operation.

[0012] Alternatively, the fixing threaded portion may be provided on the outer periphery of the guide bushing fixed to the valve body, and the valve shaft may have a large-diameter general portion that can be guided by the main body guide portion and the guide bushing when the valve is opened. When the valve is closed, a neck with a diameter smaller than the large-diameter general portion is formed at the part of the main body guide portion in the valve shaft to suppress interference between the main body guide portion and the valve shaft.

[0013] Furthermore, when the gap between the valve core and the valve port is set as a, the radius difference between the main guide portion at the position of the main guide portion and the valve shaft is set as b, and the radius difference between the guide bushing at the position of the guide bushing and the valve shaft is set as c, the relationship a < c < b is satisfied when the valve is closed, and the relationship b ≤ c < a is satisfied when the valve is fully open.

[0014] Alternatively, the valve shaft may have a small-diameter general portion that is not guided by the main body guide portion, and a large-diameter portion that is guided by the main body guide portion when the valve port orifice releases its guidance of the valve core during valve opening.

[0015] The effects of the invention

[0016] According to the present invention, an electric valve with improved actuation during valve opening can be provided. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view showing the overall structure of the electric valve in this embodiment.

[0018] Figure 2 This is an enlarged cross-sectional view showing the main part of the electric valve in this embodiment when it is closed.

[0019] Figure 3 (A) is an enlarged cross-sectional view showing the state of the electric valve of this embodiment when the valve core is inserted into the valve port orifice and the valve is closed. Figure 3 (B) is an enlarged cross-sectional view showing the state in which the neck of the electric valve in this embodiment is located in the main body guide when the valve is opened.

[0020] Figure 4 This is an enlarged cross-sectional view showing the main part of the electric valve in this embodiment when it is open.

[0021] Figure 5 (A) is an enlarged cross-sectional view showing the state of the electric valve in this embodiment when the valve core is disengaged from the valve port. Figure 5 (B) is an enlarged cross-sectional view showing the state in which the large-diameter general portion of the electric valve in this embodiment is guided by the main body guide portion when the valve is opened.

[0022] Figure 6 (A) is an enlarged cross-sectional view showing the state of the electric valve when it is closed in Modified Example 1. Figure 6 (B) is an enlarged sectional view showing the state of the electric valve when it is open in Modified Example 1.

[0023] Figure 7 (A) is an enlarged cross-sectional view showing the state of the electric valve when it is closed in Modified Example 2. Figure 7 (B) is an enlarged sectional view showing the state of the electric valve when it is open in Modified Example 2.

[0024] Figure 8 (A) is an enlarged cross-sectional view showing the state of the electric valve when it is closed in Modified Example 3. Figure 8 (B) is an enlarged sectional view showing the state of the electric valve when it is open in modified example 3.

[0025] Symbol Explanation

[0026] 1 Electric valve

[0027] 10 valve shaft

[0028] 14 valve core

[0029] 15 large diameter general part

[0030] 15a cone face

[0031] 15b cone face

[0032] 16. Neck retraction

[0033] 20 guide bushing

[0034] 23 Fixed threaded part

[0035] 28 Thread Feed Mechanism

[0036] 29 Lower stop mechanism

[0037] 33 Movable threaded part

[0038] 35 minor diameter general section

[0039] 40 valve body

[0040] 40a valve chamber

[0041] 43 Main Guide Section

[0042] 46 valve port

[0043] 46a Valve Seat Section

[0044] 50 motor

[0045] 51 rotor

[0046] 52 stator

[0047] 65 large diameter part

[0048] The gap between the valve core and the valve port

[0049] The radius difference between the constricted neck and the main guide section

[0050] The radius difference between the major diameter general part and the main body guide part Detailed Implementation

[0051] Hereinafter, the embodiments for carrying out the present invention will be described based on the accompanying drawings. Furthermore, in the figures, for ease of understanding of the invention and for ease of drawing, sometimes the gaps formed between components, the distances between components, etc., are exaggerated. Additionally, in this specification, descriptions of positions and directions such as up / down and left / right are based on… Figure 1 The directional arrows indicate a reference point and do not refer to the actual position or direction in use. Structural elements represented by the same symbol in the various figures refer to the same structural element. Furthermore, repeated descriptions and symbols in the embodiments described below are sometimes omitted.

[0052] exist Figure 1In this embodiment, the electric valve 1 mainly includes: valve shaft 10, guide bushing 20, valve shaft retainer 30, valve body 40, housing 55, stepper motor 50 composed of rotor 51 and stator 52, compression helical spring (force application component) 60, anti-disengagement and locking component 70, threaded feed mechanism 28, and lower stop mechanism 29.

[0053] The valve shaft 10 has an upper small diameter portion 11, a middle large diameter portion 12 and a lower small diameter portion 13 from the top side. A valve core 14 is integrally formed at the lower end of the lower small diameter portion 13. The valve core is used to control the flow rate of the fluid (refrigerant) flowing through the valve port 46.

[0054] like Figure 1 , Figure 2 , Figure 3 As shown in (A), the valve core 14, starting from the upper side (valve chamber 40a side), has: a cylindrical portion (valve core side cylindrical portion) 14s, an upper conical portion 14t formed by an inverted frustum conical surface, and a lower conical portion 14u formed by an inverted frustum conical surface with a control angle (the angle of intersection with a line parallel to the central axis O of the valve core 14) larger than that of the upper conical portion 14t. The cylindrical portion 14s is formed by a cylindrical surface with a diameter slightly smaller than that of the lower minor diameter portion 13 of the valve shaft 10. The outer diameter of this cylindrical surface is constant in the lifting direction.

[0055] Furthermore, an annular flat surface (horizontal surface) (valve core side abutment portion) 14f is provided on the upper side of the cylindrical portion 14s in the valve core 14, connected to the cylindrical portion 14s. This annular flat surface 14f is formed by a stepped surface formed between the lower small-diameter portion 13 of the valve shaft 10 and the valve core 14 (the cylindrical portion 14s). In addition, the annular flat surface 14f is a surface perpendicular to the lifting direction. At the origin position (lowest position) of the valve core 14 during the assembly of the electric valve 1, when the valve core 14 descends from the lowest position, the annular flat surface 14f becomes a reference surface abutting against the valve body 40. More specifically, the annular flat surface 14f becomes a reference surface abutting against the annular flat surface 45f formed on the upper surface of the bottom wall 45 of the valve body 40 as the valve body side abutment portion.

[0056] A guide bushing 20 is disposed on the valve body 40 side and has a cylindrical portion 21 and an extended configuration portion 22. The cylindrical portion 21 is inserted into the valve shaft 10 with the middle large-diameter portion 12 being able to move (slide) relative to each other along the axis O and to rotate relative to each other about the axis O. The extended configuration portion 22 extends upward from the upper end of the cylindrical portion 21 and has an inner diameter larger than the cylindrical portion 21, and is inserted into the upper end side of the middle large-diameter portion 12 and the lower end side of the upper small-diameter portion 11 of the valve shaft 10.

[0057] A fixed threaded portion (external threaded portion) 23 constituting one of the threaded feed mechanisms 28 is formed on the outer periphery of the cylindrical portion 21 of the guide bushing 20. The threaded feed mechanism 28 is a mechanism that drives the valve core 14 of the valve shaft 10 to rise and fall relative to the valve seat portion 46a of the valve body 40 based on the rotation of the rotor 51. In addition, the lower part of the cylindrical portion 21, specifically the part lower than the fixed threaded portion 23, has a larger diameter and becomes a fitting portion 27 that fits into the fitting hole 44 of the valve body 40. The lower stop 25 is threadedly fixed to the lower side of the valve shaft retainer 30 in the fixed threaded portion 23 with a predetermined gap h between it and the upper surface 27a of the fitting portion 27. The fixed stop 24 constituting one of the lower stop mechanisms 29 is integrally protruding from the outer periphery of the lower stop 25. The lower stop mechanism 29 restricts the downward rotation of the valve shaft retainer 30, that is, the valve shaft 10 connected to the valve shaft retainer 30. Furthermore, as detailed later, in this embodiment, the upper surface 27a of the fitting portion 27 serves as a stop portion that restricts the downward movement of the lower stop member 25 (in other words, defines the lower stop member 25's downward movement limit position or the lowest downward movement position).

[0058] The valve shaft retainer 30 has a cylindrical portion 31 for inserting the guide bushing 20 and a top portion 32. The top portion 32 has a through hole 32a for inserting the upper end of the upper small-diameter portion 11 of the valve shaft 10. A movable threaded portion (internal threaded portion) 33 is formed on the inner circumference of the cylindrical portion 31 of the valve shaft retainer 30. This movable threaded portion 33 engages with the fixed threaded portion 23 of the guide bushing 20 to form a threaded feed mechanism 28. A movable stop body 34, which constitutes the other part of the lower stop mechanism 29, is integrally protruding from the lower end of the outer circumference of the cylindrical portion 31 of the valve shaft retainer 30.

[0059] Furthermore, a compression coil spring (force-applying component) 60 is compressed and installed between the stepped surface formed between the upper small-diameter portion 11 and the middle large-diameter portion 12 of the valve shaft 10 and the lower surface of the top 32 of the valve shaft holder 30. The compression coil spring 60 applies force to the valve shaft 10 and the valve shaft holder 30 in the direction of separation in the lifting direction (axis O direction) by being inserted into the upper small-diameter portion 11 of the valve shaft 10; in other words, it always applies force to the valve shaft 10 (valve core 14) downward (valve closing direction).

[0060] The valve body 40 is constructed from a cylindrical body of metal such as brass or SUS. The valve body 40 has a valve chamber 40a, which is used for fluid introduction and discharge. A first conduit 41a is connected and fixed to a first, laterally oriented opening 41 located on the side of the valve chamber 40a by brazing or the like. A main guide portion 43 and a fitting hole 44 are formed at the top of the valve chamber 40a. The main guide portion allows the valve shaft 10 (its central large-diameter portion 12) to be inserted in a state where it can move (slide) relative to the axis O and rotate relative to the axis O. The lower part (fitting portion 27) of the guide bushing 20 is fitted (pressed into) into the fitting hole 44 and thus fixed in place. The main guide portion 43 is, for example, a through hole. A second conduit 42a is connected and fixed to a second, longitudinally oriented opening 42 located at the lower part of the valve chamber 40a by brazing or the like. Additionally, a generally frustoconical valve port 46 is formed, for example, in the bottom wall 45 located between the valve chamber 40a and the second opening 42. This valve port 46 has a valve seat portion 46a that is either in contact with or close to the valve core 14. A cylindrical portion (valve seat side cylindrical portion) 46s (see reference) is provided in the valve seat portion 46a. Figure 2 The inner diameter of the cylindrical section 46s remains constant in the lifting direction.

[0061] The inner diameter of the cylindrical part 46s is designed to be slightly larger than that of the cylindrical part 14s of the valve core 14, and smaller than that of the lower small diameter part 13 of the valve shaft 10.

[0062] In addition, around the valve port hole 46 (valve seat portion 46a) on the upper surface of the bottom wall 45 of the valve body 40 is an annular flat surface (horizontal surface) (valve body side abutment portion) 45f. This annular flat surface 45f becomes the abutment surface (reference surface) at the origin position (lowest position) of the valve core 14 during the assembly of the electric valve 1, which abuts against the annular flat surface 14f on the valve core 14 side with a plane (details will be described later).

[0063] On the other hand, the flange plate 47 is fixed to the upper end of the valve body 40 by brazing or the like. The lower end of the topped cylindrical housing 55 is sealed to the stepped portion provided on the outer periphery of the flange plate 47 by butt welding.

[0064] A rotor 51 is rotatably disposed inside the housing 55 and outside the guide bushing 20 and valve shaft retainer 30. A stator 52, consisting of a magnetic yoke 52a, a winding frame 52b, a stator coil 52c, and a resin molding cover 52d, is disposed outside the housing 55 to drive the rotor 51 to rotate. The stator coil 52c is connected to a plurality of lead terminals 52e, and a plurality of lead wires 52g are connected to these lead terminals 52e via a substrate 52f. By energizing the stator coil 52c, the rotor 51 disposed inside the housing 55 rotates about axis O.

[0065] The rotor 51, which is disposed in the housing 55, is engaged and supported on the valve shaft retainer 30, which rotates integrally with the rotor 51.

[0066] In detail, the rotor 51 adopts a double tube structure consisting of an inner cylinder 51a, an outer cylinder 51b and a connecting part 51c. The connecting part 51c connects the inner cylinder 51a and the outer cylinder 51b at a predetermined angular position around the axis O. For example, a longitudinal groove 51d is formed on the inner circumference of the inner cylinder 51a, extending along the axis O in the direction of the axis O (vertical direction) at 120-degree angular intervals.

[0067] On the other hand, for example, a protruding rib 30a extending vertically at 120-degree angular intervals around axis O is provided on the upper half of the outer periphery of the valve shaft retainer 30. An upward-facing locking surface (not shown) supporting the rotor 51 is formed on both sides of the lower part of the protruding rib 30a.

[0068] The longitudinal groove 51d of the inner cylinder 51a of the rotor 51 engages with the protrusion 30a of the valve shaft retainer 30, and the lower surface of the inner cylinder 51a of the rotor 51 abuts against the locking surface of the valve shaft retainer 30, thereby supporting and fixing the rotor 51 in a position aligned with the valve shaft retainer 30. Thus, the valve shaft retainer 30 supports the rotor 51 within the housing 55 while rotating together with the rotor 51.

[0069] In order to prevent relative movement between the valve shaft retainer 30 and the rotor 51 in the lifting direction, in other words, in order to press the rotor 51 downward relative to the valve shaft retainer 30 and connect the valve shaft 10 and the valve shaft retainer 30, an anti-disengagement locking component 70 is provided on the upper side of the rotor 51 and the valve shaft retainer 30.

[0070] The upper part of the anti-disengagement locking component 70 is externally fixed to the upper end of the upper small-diameter portion 11 of the valve shaft 10 by pressing, welding, etc. A flange-shaped rotor pressing member 72 is provided at the lower part of the anti-disengagement locking component 70. That is, the rotor 51 is clamped between the valve shaft retainer 30, which is subjected to upward force by the compression coil spring 60, and the rotor pressing member 72. In addition, the vertical height from the upper end of the valve shaft retainer 30 to the locking surface is the same as the vertical height of the inner cylinder 51a of the rotor 51, and the upper surface of the top 32 of the valve shaft retainer 30 abuts against the lower surface (flat surface) of the rotor pressing member 72.

[0071] In addition, a return spring 75, which is made of a coil spring, is installed on the anti-disengagement locking component 70 fixed to the upper end of the valve shaft 10. This spring applies force to the valve shaft retainer 30 toward the guide bushing 20 so that even if the valve shaft retainer 30 moves excessively upward relative to the guide bushing 20 during operation, causing the engagement between the fixed thread portion 23 of the guide bushing 20 and the movable thread portion 33 of the valve shaft retainer 30 to be released, the engagement is restored.

[0072] Furthermore, in this electric valve 1, for example, to prevent the valve core 14 from biting into the valve seat portion 46a and to ensure controllability in the low flow range, a predetermined gap is formed between the valve core 14 and the valve seat portion 46a when the valve core 14 is in its lowest position (origin position) when the valve is closed. In this example, a predetermined gap is formed between the cylindrical portion 14s of the valve core 14 and the cylindrical portion 46s of the bottom wall 45 of the valve body 40, and between the annular flat surface 14f connected to the cylindrical portion 14s and the annular flat surface 45f connected to the cylindrical portion 46s.

[0073] (Details of the valve shaft)

[0074] exist Figure 3 In (A) and (B), the valve core 14 is guided by the valve port 46 at least during valve closure. During the valve closure operation, while the valve core 14 is guided by the valve port 46, the valve shaft 10 is not guided by the main body guide portion 43 provided in the valve body 40. When the valve port 46 releases its guidance of the valve core 14 during valve opening, the valve shaft 10 is guided by the main body guide portion 43. Specifically, the valve shaft 10 is provided with a large-diameter general portion 15 that can be guided by the main body guide portion 43 during valve opening. A neck 16 is formed in the valve shaft 10 at the location of the main body guide portion 43 during valve closure. To suppress interference between the main body guide portion 43 and the valve shaft 10, the diameter of the neck 16 is set to be smaller than the large-diameter general portion 15.

[0075] In the valve shaft 10, a large-diameter general portion 15 is disposed between the neck 16 and the lower small-diameter portion 13. Tapered portions 15a and 15b are provided at both ends of the large-diameter general portion 15 along the axial direction of the valve shaft 10. Tapered portion 15a is disposed on the neck 16 side, and tapered portion 15b is disposed on the lower small-diameter portion 13 side. As an example, the intermediate large-diameter portion 12 ( Figure 2 The outer diameter of the neck 16 is equal to the outer diameter of the general portion 15. That is, the neck 16 is a portion formed by machining or the like, which reduces the diameter of a part of the general portion with a constant outer diameter from the intermediate large diameter portion 12 to the large diameter general portion 15.

[0076] The large-diameter portion 12 of the valve shaft 10 is guided by the guide bushing 20 when the valve is opened and closed. The general large-diameter portion 15 of the valve shaft 10 is guided, for example, by the main body guide portion 43 and the guide bushing 20 when the valve is opened. Therefore, the inner diameter of the main body guide portion 43 is set to be slightly smaller than the inner diameter of the guide bushing 20.

[0077] exist Figure 3In this configuration, the gap between the valve core 14 and the valve port 46 is defined as 'a', the radius difference between the main guide portion 43 at its position and the valve shaft 10 is defined as 'b', and the radius difference between the guide bushing 20 at its position and the valve shaft 10 is defined as 'c'. Thus, the valve shaft 10 and the valve body 40 can also be configured to satisfy the relationship a < c < b when the valve is closed. Furthermore, as... Figure 5 As shown, the valve shaft 10 and the valve body 40 can also be configured to satisfy the relationship b ≤ c < a when the valve is fully open. Furthermore, in Figure 5 In this process, the direction of gap a is not limited to the radial direction of the valve port 46, but is measured in the direction of the shortest distance between the valve core 14 and the valve port 46. Since the valve core 14 is located off the axis of the valve port 46, the gap a at the lower end is the radius difference between the cylindrical portions 14s and 46s.

[0078] In addition, Figure 3 In this design, the overlap length between the cylindrical portion 46s of the valve port 46 and the cylindrical portion 14s of the valve core 14 is defined as A. The axial distance between the upper end of the large-diameter general portion 15 (excluding the conical portion 15a) and the lower end of the main body guide portion 43 when the valve is closed is defined as B. The length from the lower end of the upper conical portion 14t of the valve core 14 to the upper end of the cylindrical portion 46s of the valve port 46 is defined as C. In this way, the valve shaft 10 and the valve body 40 can also be configured to satisfy the relationship A≤B<C when the valve is closed. The length of the conical portion 15a connected to the upper part of the large-diameter general portion 15 is arbitrary, but preferably B=A, and the maximum value of B is less than C. Furthermore, as an example, A=0.1~0.3mm and C=2.0mm. The diameter of the large-diameter general portion 15 of the valve shaft 10 is approximately 3mm.

[0079] exist Figure 3 In this design, the angle between the conical portion 15a and the central axis O, i.e., the conical angle, is set to approximately 30 degrees. However, this angle can be further reduced to extend the conical portion 15a towards the neck 16. In this case, it is possible to prevent the upper conical portion 14t of the valve core 14 from abutting against the valve port 46.

[0080] (effect)

[0081] In the electric valve 1 of this structure, when the rotor 51 rotates by energizing the stator coil 52c of the stator 52, the valve shaft retainer 30 and the valve shaft 10 rotate integrally with the rotor 51. At this time, the valve shaft 10 rises and falls along with the valve core 14 through the threaded feed mechanism 28, which is composed of the fixed threaded portion 23 of the guide bushing 20 and the movable threaded portion 33 of the valve shaft retainer 30. As a result, the flow rate of fluids such as refrigerant is adjusted by increasing or decreasing the gap (lifting amount, valve opening) between the valve core 14 and the valve seat portion 46a. In addition, the movable stop 34 of the valve shaft retainer 30 abuts against the fixed stop 24 fixed to the lower stop 25 of the guide bushing 20, so that even when the valve core 14 is in the most descending position, a gap is formed between the valve core 14 and the valve seat portion 46a (the required lifting amount when closing the valve), thus ensuring the specified flow rate (see reference). Figure 3 (A)).

[0082] When the valve is closed, the valve core 14 of the valve shaft 10 is guided by the valve port 46, and the middle large diameter portion 12 is guided by the guide bushing 20. Figure 3 (A)). However, a neck 16 is provided on the valve shaft 10, which is separate from the main body guide portion 43, so the valve shaft 10 is not guided by the main body guide portion 43. Figure 3 (B) Specifically, during the period when the valve core 14 is guided by the valve port 46 during valve closing and valve opening, the valve shaft 10 is not guided by the main body guide portion 43, thus suppressing interference between the valve shaft 10 and the main body guide portion 43. Therefore, compared to the case where the valve shaft 10 is always guided by the main body guide portion 43 during valve closing and valve opening, the sliding resistance when the electric valve 1 is opened is reduced, resulting in better operation. In particular, during valve closing, to satisfy Figure 3 The valve shaft 10 is constructed in a manner that combines the relationships a < c < b in (A) and (B), thereby ensuring good operation of the electric valve 1 when it is opened.

[0083] When in Figure 3 When the valve is closed, with the valve shaft 10 and valve body 40 configured to satisfy the relationship A ≤ B < C, the valve shaft 10 rises due to the valve opening action. Simultaneously with or after the partial disappearance of length A, the large-diameter general portion 15 reaches the body guide portion 43 and is guided by it. The partial disappearance of length A means that the valve orifice 46 releases the guidance of the valve core 14. Here, since B < C, the valve core 14 will not detach from the valve orifice 46 until the large-diameter general portion 15 reaches the body guide portion 43. Therefore, the valve shaft 10 can be stably supported relative to the fluid flowing through the valve orifice 46. Figure 4 , Figure 5 In the middle, when the valve is opened (fully open), the large diameter general part 15 also reaches the guide bushing 20 and is guided by the main body guide part 43 and the guide bushing 20.

[0084] Furthermore, this embodiment is not limited to the structure described above, and may also be a modified structure as described below.

[0085] [Variation Example 1]

[0086] exist Figure 6 In the electric valve 1 of Modified Example 1, a small-diameter general portion 35 is provided on the valve shaft 10 that is not guided by the main body guide portion 43 when the valve is closed. When the inner diameter of the main body guide portion 43 is equal to the inner diameter of the guide bushing 20, the small-diameter general portion 35 is not guided by either the main body guide portion 43 or the guide bushing 20. Furthermore, a large-diameter portion 65 is provided on the valve shaft 10; when the valve port orifice 46 releases its guidance of the valve core 14 during valve opening, this large-diameter portion is guided by the main body guide portion 43.

[0087] The minor diameter general portion 35 can also be formed by machining a part of a shaft component having the outer diameter of the major diameter portion 65. Alternatively, the major diameter portion 65 can be configured to fit other components such as sleeves into the minor diameter general portion 35. The structure of the major diameter portion 65 is the same as that of the major diameter general portion 15.

[0088] In this structure, when the valve is closed, the valve shaft 10 is guided by the valve port 46. Figure 6 (A)). When the valve port 46 releases the guidance of the valve core 14 during the valve opening operation, the large diameter portion 65 is guided, for example, by the main body guide portion 43 and the guide bushing 20. Figure 6 (B)

[0089] Furthermore, the large-diameter portion 65 may be guided only by the main body guide portion 43, without being guided by the guide bushing 20. Alternatively, a structure may be adopted in which the inner diameter of the guide bushing 20 is smaller than the inner diameter of the main body guide portion 43, and the small-diameter general portion 35 is guided by the guide bushing 20.

[0090] [Variation Example 2]

[0091] exist Figure 7 In the modified example 2, in the electric valve 1, with Figure 2 Compared to the structure shown, the length of the axial neck 16 of the valve shaft 10 and the length of the main body guide portion 43 are shorter, and a large-diameter bore portion 53 is formed on the lower side of the main body guide portion 43 in the valve body 40. The diameter of the large-diameter bore portion 53 is larger than the inner diameter of the main body guide portion 43. When the valve is closed, the upper part of the large-diameter general portion 15 is configured to enter the large-diameter bore portion 53.

[0092] In this structure, with Figure 2 Compared to the structure shown, the neck 16 is shorter, resulting in higher rigidity of the valve shaft 10 and making it difficult for the valve shaft 10 to vibrate due to the fluid flowing through the valve chamber 40a.

[0093] [Variation Example 3]

[0094] exist Figure 8 In the electric valve 1 of Modified Example 3, the main body guide portion 43, similar to that of Modified Example 2, is composed of a guide member 54 that is separate from the valve body 40. The guide member 54 is embedded in the fitting hole 44 of the valve body 40 and is located on the lower side of the fitting portion 27 of the guide bushing 20. Similar to Modified Example 2, a large-diameter hole portion 53 is provided in the valve body 40.

[0095] By forming the main guide portion 43 in the guide member 54, which is separate from the valve body 40, manufacturing can be simplified compared to directly machining the main guide portion 43 onto the valve body 40.

[0096] [Other Implementation Methods]

[0097] The above describes one example of an embodiment of the present invention. However, the embodiments of the present invention are not limited to the above description. Various modifications can be made without departing from the spirit of the invention.

[0098] In the above embodiment, even when the valve core 14 is in the lowest position, a gap is formed between the valve core 14 and the valve seat 46a (the required lifting amount is required when closing the valve), but it is not limited to this. A structure in which the valve core 14 and the valve seat 46a are tightly fitted together and no gap is formed between them can also be adopted.

Claims

1. An electric valve, characterized in that, The electric valve comprises: a valve shaft with a valve core; a valve body having a valve port and forming a valve chamber for fluid introduction and discharge, the valve port having a valve seat portion that contacts or separates from the valve core; a lifting mechanism for raising and lowering the valve shaft relative to the valve seat portion; and a lower stop mechanism for limiting the downward movement of the valve shaft. The valve core is guided by the valve orifice at least when the valve is closed. During the valve opening operation, while the valve core is guided by the valve port, the valve shaft is not guided by the main guide portion of the valve body, and the gap between the valve shaft and the main guide portion remains at its maximum. When the valve port releases the guidance of the valve core, the valve shaft is guided by the main guide portion. The valve shaft has a small-diameter general portion that is not guided by the main body guide portion, and a large-diameter portion. When the valve port orifice releases its guidance of the valve core during valve opening, the large-diameter portion is guided by the main body guide portion.

2. The electric valve according to claim 1, characterized in that, It comprises: an electric motor having a rotor connected to the valve shaft and a stator for rotating the rotor; and a threaded feed mechanism having a fixed threaded portion provided on the valve body side and a movable threaded portion provided on the valve shaft side, for raising and lowering the valve core of the valve shaft relative to the valve seat portion of the valve body according to the rotation drive of the rotor.

3. An electric valve, characterized in that, The electric valve comprises: a valve shaft with a valve core; a valve body having a valve port and forming a valve chamber for fluid introduction and discharge, the valve port having a valve seat portion that contacts or separates from the valve core; a lifting mechanism for raising and lowering the valve shaft relative to the valve seat portion; and a lower stop mechanism for limiting the downward movement of the valve shaft. The valve core is guided by the valve orifice at least when the valve is closed. During the valve opening operation, while the valve core is guided by the valve port, the valve shaft is not guided by the main guide portion of the valve body, and the gap between the valve shaft and the main guide portion remains at its maximum. When the valve port releases the guidance of the valve core, the valve shaft is guided by the main guide portion. The valve shaft is provided with a large-diameter general portion that can be guided by the main body guide portion when the valve is opened. When the valve is closed in the valve shaft, a neck with a diameter smaller than that of the major diameter general portion is formed at the part of the main guide portion to suppress interference between the main guide portion and the valve shaft.

4. The electric valve according to claim 3, characterized in that, It comprises: an electric motor having a rotor connected to the valve shaft and a stator for rotating the rotor; and a threaded feed mechanism having a fixed threaded portion provided on the valve body side and a movable threaded portion provided on the valve shaft side, for raising and lowering the valve core of the valve shaft relative to the valve seat portion of the valve body according to the rotation drive of the rotor.

5. The electric valve according to claim 4, characterized in that, The fixing threaded portion is provided on the outer periphery of the guide bushing fixed to the valve body. The large-diameter general section can be guided by the guide bushing when the valve is opened.

6. The electric valve according to claim 5, characterized in that, When the gap between the valve core and the valve port is set as 'a', the radius difference between the main guide portion and the valve shaft at the position of the main guide portion is set as 'b', and the radius difference between the guide bushing and the valve shaft at the position of the guide bushing is set as 'c', When the valve is closed, the relationship a < c < b must be satisfied. When the valve is fully open, the relationship b ≤ c < a is satisfied.

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