CN113757391A

CN113757391A - Electric valve

Info

Publication number: CN113757391A
Application number: CN202110274332.9A
Authority: CN
Inventors: 矢泽将志
Original assignee: Fujikoki Corp
Current assignee: Fujikoki Corp
Priority date: 2020-06-03
Filing date: 2021-03-15
Publication date: 2021-12-07
Also published as: JP7072907B2; JP2021188723A

Abstract

The invention provides an electrically operated valve, which improves the operability when the valve is opened. The motor-operated valve (1) is provided with: a valve shaft (10) provided with a valve element (14); a valve body (40) having a valve port hole (46) of a valve seat portion (46a) that is separated from or close to the valve body (14) and in which a valve chamber (40a) into which and from which fluid is introduced and discharged is formed; a lift mechanism for lifting the valve shaft relative to the valve seat; and a lower stopper mechanism (29) for restricting downward movement of the valve shaft (10), wherein the valve body (14) is guided by the valve port hole (46) at least when the valve is closed, and wherein the valve shaft (10) is not guided by a body guide section (43) provided in the valve body (40) while the valve body (14) is guided by the valve port hole (46) during the valve opening operation, and wherein the valve shaft is guided by the body guide section (43) when the valve body (14) is released from the valve port hole (46).

Description

Electric valve

Technical Field

The present invention relates to an electrically operated valve incorporated in a refrigeration cycle such as an air conditioner or a refrigerator as a flow rate control valve.

Background

As such an electric valve, a structure having the following components is known: a valve shaft provided with a valve core; a valve body provided with a valve port hole having a valve seat portion that is separated from or close to the valve body, and formed with a valve chamber into which and from which fluid is introduced and discharged; a motor having a rotor coupled to the valve shaft and a stator for rotating the rotor; a screw feed mechanism which is composed of a fixed screw portion provided on the valve body side and a movable screw portion provided on the valve shaft side, and which raises and lowers the valve body of the valve shaft relative to the valve seat portion of the valve body in accordance with the rotational drive of the rotor; and a lower stopper mechanism for restricting a downward movement of the rotation of the valve shaft (see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-180525

Technical problem to be solved by the invention

However, in the conventional structure, when the valve is closed, three portions, namely, the valve port hole, the main body guide formed of the through hole of the valve main body, and the guide bush fixed to the valve main body and having the fixed screw portion formed on the outer periphery thereof, interfere with the valve shaft, so that the sliding resistance during valve opening increases, which causes a reduction in operability.

Disclosure of Invention

The invention aims to provide an electrically operated valve with improved operability when the valve is opened.

Means for solving the problems

In order to solve the above problem, an electrically operated valve according to the present invention includes: a valve shaft provided with a valve core; a valve body provided with a valve port hole having a valve seat portion that is separated from or close to the valve body, and in which a valve chamber for introducing and discharging fluid is formed; a motor having a rotor coupled to the valve shaft and a stator for rotating the rotor; a screw feed mechanism having a fixed screw portion provided on a guide bush on the valve main body side and a movable screw portion provided on the valve shaft side, for moving up and down the valve body of the valve shaft with respect to the valve seat portion of the valve main body in accordance with rotational driving of a rotor; and a lower stopper mechanism for restricting a downward rotational movement of the valve shaft, wherein the valve body is guided by the valve port hole at least when the valve is closed, the valve shaft is not guided by a body guide provided in the valve body while the valve body is guided by the valve port hole when the valve is closed and when the valve is opened, and the valve shaft is guided by the body guide when the valve port hole is released from guiding the valve body when the valve is opened.

In this motor-driven valve, the valve shaft is not guided by the body guide while the valve body is guided by the valve port hole during valve closing and during valve opening, and therefore interference between the valve shaft and the body guide is suppressed. Therefore, the sliding resistance at the time of opening the valve is reduced and the operability is good as compared with the case where the valve shaft is guided by the body guide at all times at the time of closing the valve and during the opening operation.

Further, the fixed screw portion may be provided on an outer peripheral portion of a guide bush fixed to the valve body, the valve shaft may be provided with a large-diameter general portion that can be guided by the body guide portion and the guide bush when the valve is opened, and a constricted portion having a smaller diameter than the large-diameter general portion may be formed at a portion of the valve shaft that is located on the body guide portion when the valve is closed, so as to suppress interference between the body guide portion and the valve shaft.

Further, when a clearance between the valve body and the valve port hole is defined as a, a radius difference between the valve shaft and the main body guide at the position of the main body guide is defined as b, and a radius difference between the valve shaft and the guide bush at the position of the guide bush is defined as c, a relationship of a < c < b may be satisfied when the valve is closed, and a relationship of b < c < a may be satisfied when the valve is fully opened.

Further, the valve shaft may be provided with 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 is released from guiding the valve body during valve opening operation.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide an electrically operated valve having improved operability when the valve is opened.

Drawings

Fig. 1 is a sectional view showing the overall structure of an electrically operated valve according to the present embodiment.

Fig. 2 is an enlarged cross-sectional view of a main portion showing a state when the motor-operated valve of the present embodiment is closed.

Fig. 3 (a) is an enlarged cross-sectional view showing a state of the motor-operated valve of the present embodiment when the valve body is closed by inserting the valve element into the valve port hole. Fig. 3 (B) is an enlarged cross-sectional view showing a state in which the constricted portion is positioned in the main body guide portion when the motor-operated valve of the present embodiment is opened.

Fig. 4 is an enlarged cross-sectional view of a main portion showing a state when the motor-operated valve of the present embodiment is opened.

Fig. 5 (a) is an enlarged cross-sectional view showing a state of the motor-operated valve of the present embodiment when the valve element is opened to disengage the valve element from the valve hole. Fig. 5 (B) is an enlarged cross-sectional view showing a state in which the large-diameter general portion is guided by the main body guide portion when the motor-operated valve of the present embodiment is opened.

Fig. 6 (a) is an enlarged cross-sectional view showing a state when the motor-operated valve of modification 1 is closed. Fig. 6 (B) is an enlarged cross-sectional view showing a state when the motor-operated valve of modification 1 is opened.

Fig. 7 (a) is an enlarged cross-sectional view showing a state when the motor-operated valve of modification 2 is closed. Fig. 7 (B) is an enlarged cross-sectional view showing a state when the motor-operated valve of modification 2 is opened.

Fig. 8 (a) is an enlarged cross-sectional view showing a state when the motor-operated valve of modification 3 is closed. Fig. 8 (B) is an enlarged cross-sectional view showing a state when the motor-operated valve of modification 3 is opened.

Description of the symbols

1 electric valve

10 valve shaft

14 valve core

15 major diameter general part

15a conical surface part

15b tapered surface portion

16 necking part

20 guide bush

23 fixed screw part

28 screw thread feeding mechanism

29 lower stop mechanism

33 Movable screw part

35 minor diameter general part

40 valve body

40a valve chamber

43 main body guide part

46 valve port hole

46a valve seat portion

50 electric machine

51 rotor

52 stator

65 big diameter part

a clearance between valve core and valve port hole

b radius difference between neck and body guide

c radius difference between the large diameter general part and the main body guide part

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, gaps formed between the members, a distance between the members, and the like may be exaggerated for the purpose of facilitating understanding of the invention and facilitating drawing. In the present specification, the description of the positions and directions such as up and down, left and right is based on the directional arrows in fig. 1, and does not refer to the positions and directions in the actual usage state. The constituent elements denoted by the same reference numerals in the drawings refer to the same constituent elements. In the embodiments described below, redundant descriptions and symbols may be omitted.

In fig. 1, the motor-operated valve 1 of the present embodiment mainly includes: the valve shaft 10, the guide bush 20, the valve shaft holder 30, the valve body 40, the housing 55, the stepping motor 50 including the rotor 51 and the stator 52, the compression coil spring (urging member) 60, the retaining/locking member 70, the screw feed mechanism 28, and the lower stopper mechanism 29.

The valve shaft 10 includes an upper small diameter portion 11, an intermediate large diameter portion 12, and a lower small diameter portion 13 from the upper side, and a valve body 14 for controlling the flow rate of the fluid (refrigerant) flowing through the valve port hole 46 is integrally formed at the lower end portion of the lower small diameter portion 13.

As shown in fig. 1, 2, and 3 (a), the valve body 14 includes, from the upper side (valve chamber 40a side): a cylindrical portion (valve element side cylindrical portion) 14s, an upper tapered surface portion 14t formed by an inverted conical surface, and a lower tapered surface portion 14u formed by an inverted conical surface having a control angle (intersection angle with respect to a line parallel to the central axis O of the valve element 14) larger than that of the upper tapered surface portion 14 t. The cylindrical portion 14s is formed of a cylindrical surface having a diameter slightly smaller than the lower small diameter portion 13 of the valve shaft 10. The outer diameter of the cylindrical surface is constant in the lifting direction.

Further, an annular flat surface (horizontal surface) (valve body side contact portion) 14f is provided on the valve body 14 above the cylindrical portion 14s so as to be connected to the cylindrical portion 14 s. The 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 cylindrical portion 14s of) the valve body 14. The annular flat surface 14f is a surface perpendicular to the ascending/descending direction, and at the origin position (the lowermost position) of the valve element 14 at the time of assembling the motor-operated valve 1, when the valve element 14 descends from the lowermost position, the annular flat surface 14f is a reference surface that comes into contact with the valve main body 40, and more specifically, the annular flat surface 14f is a reference surface that comes into contact with an annular flat surface 45f that is a valve main body side contact portion formed on the upper surface of the bottom wall 45 of the valve main body 40.

The guide bush 20 is provided on the valve main body 40 side, and has a cylindrical portion 21 and an extension arrangement portion 22. The cylindrical portion 21 is used for inserting the intermediate large diameter portion 12 of the valve shaft 10 in a state of being relatively movable (slidable) in the direction of the axis O and relatively rotatable about the axis O. The extension portion 22 extends upward from the upper end of the cylindrical portion 21, has an inner diameter larger than that of the cylindrical portion 21, and inserts the upper end side of the intermediate large diameter portion 12 and the lower end side of the upper small diameter portion 11 of the valve shaft 10.

A fixed screw portion (male screw portion) 23 constituting a screw feeding mechanism 28 is formed on the outer periphery of the cylindrical portion 21 of the guide bush 20. The screw feed mechanism 28 is a mechanism that moves up and down the valve body 14 of the valve shaft 10 with respect to the valve seat portion 46a of the valve main body 40 by the rotational drive of the rotor 51. A lower portion of the cylindrical portion 21, specifically, a portion below the fixed screw portion 23 has a large diameter, and is a fitting portion 27 to be fitted into the fitting hole 44 of the valve main body 40. The lower stopper 25 is screwed and fixed to the lower side of the valve shaft holder 30 in the fixed screw portion 23 with a predetermined gap h from the upper surface 27a of the fitting portion 27. One fixed stopper 24 constituting the lower stopper mechanism 29 is integrally provided to protrude from the outer periphery of the lower stopper 25. The lower stopper mechanism 29 restricts the downward rotational movement of the valve shaft holder 30, that is, the valve shaft 10 coupled to the valve shaft holder 30. Further, as will be described later in detail, in the present embodiment, the upper surface 27a of the fitting portion 27 serves as a stopper portion that restricts downward movement of the lower stopper 25 (in other words, defines a downward movement limit position or a lowermost movement position of the lower stopper 25).

The valve shaft holder 30 has a cylindrical portion 31 into which the guide bush 20 is inserted, and a top portion 32. The top portion 32 has a through hole 32a through which the upper end of the upper small diameter portion 11 of the valve shaft 10 is inserted. A movable screw portion (female screw portion) 33 is formed on the inner periphery of the cylindrical portion 31 of the valve shaft holder 30, and the movable screw portion 33 is screwed with the fixed screw portion 23 of the guide bush 20 to constitute the screw feeding mechanism 28. The other movable stopper 34 constituting the lower stopper mechanism 29 is integrally provided to protrude from the outer peripheral lower end of the cylindrical portion 31 of the valve shaft holder 30.

A compression coil spring (urging member) 60 is mounted in a compressed manner between a stepped surface formed between the upper small diameter portion 11 and the intermediate large diameter portion 12 of the valve shaft 10 and the lower surface of the top portion 32 of the valve shaft holder 30. The compression coil spring 60 is a member that biases the valve shaft 10 and the valve shaft holder 30 in a direction in which the valve shaft 10 and the valve shaft holder 30 are separated in the ascending/descending direction (the axis O direction) so as to be externally inserted to the upper small diameter portion 11 of the valve shaft 10, in other words, biases the valve shaft 10 (the valve body 14) downward (the valve closing direction) at all times.

The valve main body 40 is formed of a cylindrical body made of metal such as brass or SUS. The valve body 40 has a valve chamber 40a into and from which fluid is introduced and discharged, and a first pipe 41a is fixedly connected to a first opening 41 provided in a lateral direction of a side portion of the valve chamber 40a by brazing or the like. A body guide portion 43 through which (the intermediate large diameter portion 12 of) the valve shaft 10 is inserted in a relatively movable (slidable) manner in the axis O direction and in a relatively rotatable manner about the axis O, and a fitting hole 44 in which the lower portion (the fitting portion 27) of the guide bush 20 is fitted (press-fitted in the present embodiment) to the fitting hole 44 and fixed are formed in the top portion of the valve chamber 40 a. The main body guide 43 is, for example, a through hole. The second pipe 42a is connected and fixed to a second opening 42 facing the vertical direction provided in a lower portion of the valve chamber 40a by brazing or the like. Further, a valve port hole 46 having a substantially truncated cone shape, for example, is formed in the bottom wall 45 provided between the valve chamber 40a and the second opening 42, and the valve port hole 46 has a seat portion 46a which is separated from or close to the valve body 14. The valve seat portion 46a is provided with a cylindrical portion (valve seat side cylindrical portion) 46s (see fig. 2). The inner diameter of the cylindrical portion 46s is constant in the ascending and descending direction.

The inner diameter of the cylindrical portion 46s is designed to be slightly larger than the cylindrical portion 14s of the valve element 14 and smaller than the lower small diameter portion 13 of the valve shaft 10.

Further, the periphery of the valve port hole 46 (valve seat portion 46a) in the upper surface of the bottom wall 45 of the valve main body 40 is an annular flat surface (horizontal surface) (valve main body side contact portion) 45f, and this annular flat surface 45f becomes a contact surface (reference surface) that is in flat contact with the annular flat surface 14f on the valve element 14 side at the origin position (lowest position) of the valve element 14 at the time of assembly of the motor-operated valve 1 (details will be described later).

On the other hand, the flange-like plate 47 is fixed to the upper end portion of the valve main body 40 by brazing or the like. The lower end portion of the topped cylindrical case 55 is hermetically joined to a stepped portion provided on the outer periphery of the flange-like plate 47 by butt welding.

A rotor 51 is rotatably disposed inside the housing 55 and outside the guide bush 20 and the valve shaft holder 30, and a stator 52 including a yoke 52a, a bobbin 52b, a stator coil 52c, a resin mold cover 52d, and the like is disposed outside the housing 55 to rotationally drive the rotor 51. A plurality of lead terminals 52e are connected to the stator coil 52c, a plurality of lead wires 52g are connected to the lead terminals 52e via a base plate 52f, and the rotor 51 disposed in the housing 55 is rotated about the axis O by energization and excitation of the stator coil 52 c.

The rotor 51 disposed in the housing 55 is engaged with and supported by the valve shaft holder 30, and the valve shaft holder 30 rotates integrally with the rotor 51.

More specifically, the rotor 51 has a double-tube structure including an inner tube 51a, an outer tube 51b, and a connecting portion 51c, the connecting portion 51c connecting the inner tube 51a and the outer tube 51b at a predetermined angular position about the axis O, and vertical grooves 51d extending in the direction of the axis O (vertical direction) at angular intervals of 120 degrees about the axis O are formed on the inner circumference of the inner tube 51a, for example.

On the other hand, a ridge 30a extending in the vertical direction at an angular interval of 120 degrees around the axis O is provided in a protruding manner on the upper half of the outer periphery of the valve shaft holder 30. Upward engaging surfaces (not shown) for supporting the rotor 51 are formed on both sides of the lower portion of the ridge 30 a.

The vertical groove 51d of the inner cylinder 51a of the rotor 51 is engaged with the protrusion 30a of the valve shaft holder 30, and the lower surface of the inner cylinder 51a of the rotor 51 abuts against the locking surface of the valve shaft holder 30, whereby the rotor 51 is supported and fixed in a state of being aligned with respect to the valve shaft holder 30. Thus, the valve shaft holder 30 rotates together with the rotor 51 while supporting the rotor 51 in the housing 55.

The anti-slip locking member 70 is provided above the rotor 51 and the valve shaft holder 30 to prevent relative movement between the valve shaft holder 30 and the rotor 51 in the vertical direction, in other words, to press the rotor 51 downward with respect to the valve shaft holder 30, and to connect the valve shaft 10 and the valve shaft holder 30 to each other.

The upper portion of the retaining member 70 is fitted and fixed to the upper end portion of the upper small diameter portion 11 of the valve shaft 10 by press fitting, welding, or the like. A flange-shaped rotor pressing member 72 is provided at a lower portion of the disengagement prevention locking member 70. That is, the rotor 51 is sandwiched between the valve shaft holder 30 biased upward by the biasing force of the compression coil spring 60 and the rotor holder 72. The height in the vertical direction from the upper end of the valve shaft holder 30 to the locking surface is the same as the height in the vertical direction of the inner cylinder 51a of the rotor 51, and the upper surface of the top portion 32 of the valve shaft holder 30 abuts against the lower surface (flat surface) of the rotor retainer 72.

Further, a return spring 75 made of a coil spring for biasing the valve shaft holder 30 toward the guide bush 20 is externally attached to the retaining locking member 70 fixed to the upper end portion of the valve shaft 10 so that the screwing is restored even when the valve shaft holder 30 excessively moves upward relative to the guide bush 20 during operation and the screwing of the fixed screw portion 23 of the guide bush 20 and the movable screw portion 33 of the valve shaft holder 30 is released.

In the motor-driven valve 1, for example, in order to prevent the valve element 14 from biting into the seat portion 46a and to ensure controllability in a low flow rate region, when the valve element 14 is located at the lowest position (original position) at the time of valve closing, a gap of a predetermined size is formed between the valve element 14 and the seat portion 46 a. In this example, a gap of a predetermined size is formed between the cylindrical portion 14s of the valve element 14 and the cylindrical portion 46s of the bottom wall 45 of the valve main 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 46 s.

(details of the valve shaft)

In fig. 3 (a) and (B), the valve body 14 is guided by the valve port hole 46 at least when the valve is closed. While the valve shaft 10 is not guided by the body guide portion 43 provided in the valve body 40 during the valve closing operation in which the valve body 14 is guided by the valve port hole 46, the valve shaft 10 is guided by the body guide portion 43 when the valve port hole 46 is released from guiding the valve body 14 during the valve opening operation. 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 when the valve is opened. A constricted portion 16 is formed in the valve shaft 10 at a position located at the main body guide portion 43 when the valve is closed. The diameter of the constricted portion 16 is set smaller than the large-diameter portion 15 in order to suppress interference between the body guide portion 43 and the valve shaft 10.

In the valve shaft 10, the large diameter general portion 15 is provided between the constricted portion 16 and the lower small diameter portion 13.

Tapered surfaces

15a and 15b are provided at both ends of the large-diameter general portion 15 in the axial direction of the valve shaft 10. The tapered surface portion 15a is provided on the side of the constricted portion 16, and the tapered surface portion 15b is provided on the side of the lower small diameter portion 13. For example, the outer diameter of the intermediate large-diameter portion 12 (fig. 2) is equal to the outer diameter of the large-diameter general portion 15. That is, the constricted portion 16 is a portion in which a part of a normal portion having a constant outer diameter from the intermediate large diameter portion 12 to the large diameter normal portion 15 is reduced in diameter by cutting or the like.

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

In fig. 3, a is a clearance between the valve element 14 and the valve port hole 46, b is a difference in radius between the main body guide 43 and the valve shaft 10 at the position of the main body guide 43, and c is a difference in radius between the guide bush 20 and the valve shaft 10 at the position of the guide bush 20. In this way, the valve shaft 10 and the valve body 40 may be configured to satisfy the relationship of a < c < b when the valve is closed. Further, as shown in FIG. 5, the valve shaft 10 and the valve body 40 may be configured to satisfy the relationship of b ≦ c < a when the valve is fully opened. In fig. 5, the measurement direction of the clearance a is not limited to the radial direction of the valve port hole 46, but is measured in the direction of the shortest distance between the valve element 14 and the valve port hole 46. Since the valve body 14 is located at a position offset from the axis of the valve port hole 46, the clearance a at the lower end position is a difference in the radii of the

cylindrical portions

14s, 46 s.

In fig. 3, a length of the cylindrical portion 46s of the valve port hole 46 overlapping the cylindrical portion 14s of the valve body 14 is denoted by a, an axial distance between an upper end (a portion other than the tapered portion 15 a) of the large-diameter general portion 15 and a lower end of the main body guide portion 43 when the valve is closed is denoted by B, and a length from a lower end of the upper tapered portion 14t of the valve body 14 to an upper end of the cylindrical portion 46s of the valve port hole 46 is denoted by C. Thus, the valve shaft 10 and the valve body 40 may be configured to satisfy the relationship of A ≦ B < C when the valve is closed. The length of the tapered surface portion 15a connected to the upper portion of the large diameter general portion 15 is arbitrary, but B is preferably equal to a, and the maximum value of B is preferably smaller than C. Further, for example, a is 0.1 to 0.3mm, and C is 2.0 mm. The large diameter portion 15 of the valve shaft 10 has a diameter of about 3 mm.

In fig. 3, the angle of the tapered surface portion 15a with respect to the central axis O, that is, the tapered surface angle is about 30 degrees, but the angle may be further reduced so that the tapered surface portion 15a extends toward the constricted portion 16. In this case, the upper tapered surface portion 14t of the valve body 14 can be prevented from abutting on the valve port hole 46 side.

(action)

In the motor-operated valve 1 having this configuration, when the rotor 51 is rotated by energization and excitation of the stator coil 52c of the stator 52, the valve shaft holder 30 and the valve shaft 10 are rotated integrally with the rotor 51. At this time, the valve shaft 10 is lifted and lowered along with the valve body 14 by the screw feeding mechanism 28 including the fixed screw portion 23 of the guide bush 20 and the movable screw portion 33 of the valve shaft holder 30. Thereby, the clearance (lift amount, valve opening degree) between the valve body 14 and the valve seat portion 46a is increased or decreased to adjust the flow rate of the fluid such as the refrigerant. Further, the movable stopper 34 of the valve shaft holder 30 abuts against the fixed stopper 24 of the lower stopper 25 fixed to the guide bush 20, and even when the valve body 14 is located at the lowermost position, a gap (required lift amount at the time of valve closing) is formed between the valve body 14 and the valve seat portion 46a, and thus a predetermined amount of flow rate is secured (see fig. 3 a).

When the valve is closed, the valve element 14 of the valve shaft 10 is guided by the valve port hole 46, and the intermediate large diameter portion 12 is guided by the guide bush 20 (fig. 3 a). However, since the valve shaft 10 is provided with the constricted portion 16 and the constricted portion 16 is separated from the main body guide portion 43, the valve shaft 10 is not guided by the main body guide portion 43 ((B) of fig. 3). Specifically, the valve shaft 10 is not guided by the body guide 43 while the valve body 14 is guided by the valve port hole 46 during the valve closing operation and the valve opening operation, and therefore interference between the valve shaft 10 and the body guide 43 is suppressed. Therefore, the sliding resistance when the motor-operated valve 1 is opened is reduced and the operability is improved, as compared with the case where the valve shaft 10 is guided by the body guide 43 at all times during the valve closing and the valve opening. In particular, when the valve is closed, the valve shaft 10 is configured to satisfy the relationship of a < c < B in (a) and (B) in fig. 3, so that the operability when the electric valve 1 is opened is improved.

When the valve shaft 10 and the valve body 40 are configured to satisfy the relationship of a ≦ B < C when the valve is closed as shown in fig. 3, the valve shaft 10 is raised by the valve opening operation, and the large-diameter general portion 15 reaches the body guide portion 43 and is guided by the body guide portion 43 simultaneously with or after the disappearance of the length a. The absence of a portion of the length a means that the valve port hole 46 is not guiding the valve element 14. Here, since B < C, the valve body 14 does not come off from the valve hole 46 until the large diameter general portion 15 reaches the main body guide portion 43. Therefore, the valve shaft 10 can be stably supported with respect to the fluid flowing through the valve port hole 46. In fig. 4 and 5, even when the valve is opened (fully opened), the large-diameter general portion 15 reaches the guide bush 20 and is guided by the main body guide portion 43 and the guide bush 20.

The present embodiment is not limited to the above configuration, and may be configured as a modification example described below.

[ modification 1]

In fig. 6, in the motor-operated valve 1 of modification 1, the valve shaft 10 is provided with a small-diameter general portion 35 that is not guided by the 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 bush 20, the small-diameter general portion 35 is not guided by either the main body guide portion 43 or the guide bush 20. The valve shaft 10 is provided with a large diameter portion 65 which is guided by the main body guide portion 43 when the valve port hole 46 releases the guide of the valve element 14 during the valve opening operation.

The small-diameter normal portion 35 may be formed by cutting a part of a shaft member having an outer diameter of the large-diameter portion 65. The large diameter portion 65 may be configured by fitting another member such as a sleeve to the small diameter general portion 35. The large diameter portion 65 has the same structure as the large diameter general portion 15.

In this configuration, when the valve is closed, the valve shaft 10 is guided by the valve port hole 46 (fig. 6 a). When the valve opening hole 46 releases the guide of the valve body 14 during the valve opening operation, the large diameter portion 65 is guided by, for example, the body guide portion 43 and the guide bush 20 (fig. 6B).

Further, the large diameter portion 65 may be guided only by the main body guide portion 43 without being guided by the guide bush 20. Further, the inner diameter of the guide bush 20 may be made smaller than the inner diameter of the main body guide portion 43, and the small diameter general portion 35 may be guided by the guide bush 20.

[ modification 2]

In fig. 7, in the motor-operated valve 1 according to modification 2, the length of the constricted portion 16 and the length of the main body guide portion 43 in the axial direction of the valve shaft 10 are formed shorter than those of the configuration shown in fig. 2 and the like, and a large-diameter hole portion 53 is formed in the valve main body 40 below the main body guide portion 43. The large-diameter hole 53 is formed to have a diameter larger than the inner diameter of the main body guide 43. When the valve is closed, the upper portion of the large diameter general portion 15 is configured to enter the large diameter hole portion 53.

In this configuration, since the length of the constricted portion 16 is formed shorter than that of the configuration shown in fig. 2 and the like, the rigidity of the valve shaft 10 is high, and vibration of the valve shaft 10 due to the fluid flowing through the valve chamber 40a is less likely to occur.

[ modification 3]

In fig. 8, in the motor-operated valve 1 according to modification 3, the body guide portion 43 similar to that of modification 2 is formed of a guide member 54 separate from the valve body 40. The guide member 54 is fitted to the fitting hole 44 of the valve main body 40 below the fitting portion 27 of the guide bush 20. The large-diameter hole portion 53 is provided in the valve main body 40, as in modification 2.

By forming the main body guide portion 43 in the guide member 54 that is separate from the valve main body 40, manufacturing can be facilitated as compared with directly processing the main body guide portion 43 with respect to the valve main body 40.

[ other embodiments ]

While the embodiments of the present invention have been described above as examples, the embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

In the above embodiment, even when the valve body 14 is at the lowermost position, a gap is formed between the valve body 14 and the valve seat portion 46a (the lift amount is required when the valve is closed), but the present invention is not limited to this, and a structure may be adopted in which the valve body 14 and the valve seat portion 46a are in close contact with each other and no gap is formed therebetween.

Claims

1. An electric valve is characterized in that the electric valve is provided with a valve body,

the motor-operated valve is provided with: a valve shaft provided with a valve core; a valve body provided with a valve port hole having a valve seat portion that is separated from or close to the valve body, and in which a valve chamber for introducing and discharging fluid is formed; an elevating mechanism that elevates the valve shaft with respect to the valve seat portion; and a lower stop mechanism for limiting downward movement of the valve shaft,

the valve core is guided by the valve port hole at least when the valve is closed,

while the valve body is guided by the valve port hole during the valve opening operation, the valve shaft is not guided by a body guide provided in the valve body, and when the valve port hole is released from guiding the valve body, the valve shaft is guided by the body guide.

2. Electrically operated valve according to claim 1,

the valve shaft is provided with 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 is released from guiding the valve element during valve opening operation.

3. Electrically operated valve according to claim 1 or 2,

the drive unit includes: a motor having a rotor coupled to the valve shaft and a stator for rotating the rotor; and a screw feed mechanism having a fixed screw portion provided on the valve body side and a movable screw portion provided on the valve shaft side, for moving up and down the valve body of the valve shaft with respect to the valve seat portion of the valve body in accordance with rotational driving of the rotor.

4. Electrically operated valve according to claim 3,

the fixed screw portion is provided on an outer peripheral portion of a guide bush fixed to the valve main body,

the valve shaft is provided with a large-diameter general portion that can be guided by the main body guide portion and the guide bush when the valve is opened,

a constricted portion having a smaller diameter than the large-diameter general portion is formed at a portion of the valve shaft located at the main body guide portion when the valve is closed, so as to suppress interference between the main body guide portion and the valve shaft.

5. Electrically operated valve according to claim 4,

when a clearance between the valve body and the valve port hole is defined as "a", a radial difference between the body guide and the valve shaft at the position of the body guide is defined as "b", and a radial difference between the guide bush and the valve shaft at the position of the guide bush is defined as "c",

when the valve is closed, the relation of a < c < b is satisfied,

when the valve is fully opened, the relation that b is less than or equal to c and less than a is satisfied.