JP6757996B2 - Solenoid valve - Google Patents

Description

The present invention relates to an electric valve including a valve body provided with a valve chamber and a valve port (orifice) and a valve body that changes the flow rate of a fluid flowing through the valve port according to a lift amount, and particularly a heat pump. The present invention relates to an electric valve suitable for controlling a refrigerant flow rate in a type heating / cooling system or the like.

As an electric valve of this type, for example, the one described in Patent Document 1 is already known.

FIG. 6 shows a main part of the above-mentioned conventional motorized valve. The motorized valve 2 of the conventional example shown has a valve body 40 provided with a valve chamber 40a, a valve seat 46a, and a valve port 46 connected to the valve seat 46a, and a valve port 46 according to the amount of lift from the valve seat 46a. A valve body 14 for changing the flow rate of the flowing fluid is provided, and the valve body 14 is provided with a threaded pipe (also referred to as a guide bush) provided with a male threaded portion and a female threaded portion as described in, for example, Patent Document 1. It is moved up and down so as to be brought into contact with and separated from the valve seat 46a by a screw feed type elevating drive mechanism including the valve shaft holder and the stepping motor.

The valve body 14 changes the flow rate of the fluid flowing through the valve port 46 according to the lift amount, which is connected to the seating surface portion 14a formed of the inverted conical base surface that contacts the valve seat 46a and the lower side (tip side) of the seating surface portion 14a. It has a curved surface portion 14b for making the surface. The curved surface portion 14b is a multi-stage (here, two-stage) inverted truncated cone-shaped taper in which the control angle (intersection angle between the central axis O of the valve body 14 and the line parallel to the valve body 14) is gradually increased as it approaches the tip. It has a surface portion (upper tapered surface portion 14ba and lower tapered surface portion 14bb). As the curved surface portion 14b, an elliptical spherical surface portion (elliptical spherical surface portion) in which the bending degree of the outer peripheral surface thereof gradually becomes tighter (larger curvature) as it approaches the tip is also known.

On the other hand, the valve port 46 is a diameter-expanded portion composed of a narrowest portion 46s formed of a cylindrical surface connected to the valve seat 46a and a conical base surface connected to the lower side of the narrowest portion 46s and whose inner diameter is increased toward the lower side. It has 46b and.

Japanese Unexamined Patent Publication No. 2011-208716

By the way, in recent years, in this type of electric valve, improvement in controllability in a low flow rate region is required due to the use of R32 refrigerant and an increase in partial load operation. The same applies to the closed valve type motorized valve used in a cooling and heating system such as a multi air conditioner, and it is desired to reduce the rising flow rate.

However, in the electric valve of the conventional example as shown in FIG. 6, the rising flow rate is the outer diameter (φA) of the intersection of the seating surface portion 14a and the curved surface portion 14b (upper tapered surface portion 14ba) and the valve port 46. Since it is formed by the difference from the diameter (φB) of the narrowest portion 46s and the dimensional measurement of the outer diameter (φA) of the intersecting portion (particularly, the dimensional measurement by a contact type measuring instrument) is complicated, the rising flow rate is concerned. There was a problem that it was difficult to manage.

To solve such a problem, a straight portion having a constant outer diameter in the elevating direction (center axis O direction) is provided between the seating surface portion 14a and the curved surface portion 14b (upper tapered surface portion 14ba), and the dimension is measured by the straight portion. Although it has already been studied to simplify the above, there is a concern that the resolution (particularly, the resolution in the low flow rate region) will be lowered because a region where the flow rate does not change is generated only by such measures.

Further, at the intersection of the seating surface portion 14a and the curved surface portion 14b (upper tapered surface portion 14ba) and the intersection portion of the seating surface portion 14a and the straight portion, an angle R (also referred to as a blade R) is generated in processing. In order to avoid such seating at the angle R, it is necessary to set the outer diameter of the curved surface portion 14b and the straight portion to be relatively small with respect to the diameter of the narrowest portion 46s of the valve opening 46. As a result, there is a concern that the reduction of the rising flow rate will be insufficient.

The present invention has been made in view of the above problems, and an object of the present invention is to simplify the management of the rising flow rate, sufficiently reduce the rising flow rate, and effectively controllability in a low flow rate range. The purpose is to provide an electric valve that can be improved.

In order to solve the above-mentioned problems, the electric valve according to the present invention basically changes the flow rate of the fluid flowing through the valve port and the valve body having the valve chamber and the valve port with the valve seat according to the lift amount. The valve body is provided with a seating surface portion formed of an inverted conical base surface that is in contact with the valve seat, and the valve body is inserted through the valve opening in a continuous or stepwise manner as the curvature or control angle approaches the tip. An enlarged curved surface portion is provided, and a constricted surface portion having an outer diameter narrower than the base end portion of the curved surface portion is provided between the seating surface portion and the curved surface portion, and the inner diameter of the valve seat is the valve. It is characterized in that it is larger than the outer diameter of the tip end portion of the seating surface portion of the body, and the outer diameter of the tip end portion of the seating surface portion is larger than the outer diameter of the base end portion of the curved surface portion.

In a preferred embodiment, a straight portion having a constant outer diameter in the elevating direction is further provided between the constricted surface portion and the curved surface portion of the valve body.

In another preferred embodiment, the valve opening is provided with a narrowest portion made of a cylindrical surface connected to the valve seat.

In another preferred embodiment, the constricted surface portion is formed of an annular concave surface in a cross section including an axis.

According to the present invention, a constricted surface portion having an outer diameter narrower than that of the base end portion of the curved surface portion is provided between the seating surface portion and the curved surface portion of the valve body. Therefore, the constricted surface portion can suppress the occurrence of the angle R on the seating surface portion, and the seating at the corner R as described above can be avoided while keeping the outer diameter of the curved surface portion large. Therefore, for example, the lower side (tip side) of the seating surface portion. ) Is connected to a curved surface or a straight part, the rising flow rate can be sufficiently reduced while simplifying the management of the rising flow rate, and the controllability in the low flow rate range can be effectively improved. ..

In addition, by providing a straight portion with a constant outer diameter in the ascending / descending direction between the constricted surface portion and the curved surface portion of the valve body, the control of the rising flow rate is further simplified and the controllability in the low flow rate range is further improved. It is possible to improve effectively.

The vertical sectional view which shows one Embodiment of the electric valve which concerns on this invention. An enlarged vertical cross-sectional view of a main part of the motorized valve shown in FIG. 1 in an enlarged manner. The figure which shows the flow rate characteristic of the electric valve shown in FIG. FIG. 3 is an enlarged vertical cross-sectional view of a main part of another example of the motorized valve shown in FIG. (A) to (C) are enlarged vertical cross-sectional views of the main part of the motorized valve shown in FIG. 1 in which the main part of another example is enlarged. An enlarged vertical sectional view of a main part of a conventional solenoid valve in an enlarged manner.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the gaps formed between the members, the separation distance between the members, etc. may be exaggerated in order to facilitate understanding of the invention and for convenience in drawing. is there. Further, in the present specification, the description indicating the position and direction such as up and down, left and right, etc. is based on the direction arrow display of FIG. 1, and does not indicate the position and direction in the actual use state.

FIG. 1 is a vertical sectional view showing an embodiment of an electric valve according to the present invention.

The motorized valve 1 of the illustrated embodiment is used for adjusting the refrigerant flow rate in, for example, a heat pump type heating / cooling system, and is mainly a valve shaft 10 having a valve body 14, a guide bush 20, and a valve shaft holder. A stepping motor 50 including a valve body 40, a valve body 40, a can 55, a rotor 51 and a stator 52, a compression coil spring 60, a retaining locking member 70, a screw feed mechanism 28, and a lower stopper mechanism 29. To be equipped.

The valve shaft 10 has 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 fluid (refrigerant) flowing through the valve port 46 at the lower end portion of the lower small diameter portion 13. A valve body 14 for controlling the passing flow rate of the valve body 14 is integrally formed.

As can be clearly seen by referring to FIG. 2 together with FIG. 1, the valve body 14 has a seating surface portion 14a formed of an inverted conical base surface that is attached (seat) to the valve seat 46a from the upper side (valve chamber 40a side) and a valve. It is inserted through the port 46 and has a curved surface portion 14b for changing the flow rate of the fluid flowing through the valve port 46 according to the amount of lift from the valve seat 46a. The curved surface portion 14b has a plurality of steps (here, two steps) of inverted truncated cone-shaped tapers in which the control angle (intersection angle between the central axis O of the valve body 14 and the line parallel to the valve body 14) is gradually increased as it approaches the tip. Has a surface. Here, the plurality of stages (two stages) of the inverted truncated cone-shaped tapered surface portion is a lower tapered surface portion 14bb composed of an upper tapered surface portion 14ba made of an inverted truncated cone surface and an inverted truncated cone surface having a larger control angle than the upper tapered surface portion 14ba. And have.

Further, between the seating surface portion 14a and the curved surface portion 14b of the valve body 14 (in other words, directly below the seating surface portion 14a and directly above the curved surface portion 14b), the lower end portion (tip portion) and the curved surface portion of the seating surface portion 14a are formed. A constricted surface portion 14c having a narrower outer diameter than the upper end portion (base end portion) of the portion 14b is provided. In this example, the constricted surface portion 14c is formed of an annular concave surface (curved surface) having a constant curvature in a cross section including the central axis O, but the shape thereof is not limited to the illustrated example (other than the constricted surface portion). The shape of is described later). The height of the constricted surface portion 14c in the vertical direction (axis O direction) is designed in consideration of, for example, the rising characteristic of the flow rate.

The guide bush 20 includes a cylindrical portion 21 inserted in a state in which the valve shaft 10 (intermediate large diameter portion 12) can move (slide) relative to the axis O and can rotate relative to the axis O. It extends upward from the upper end of the cylindrical portion 21, has an inner diameter larger than that of the cylindrical portion 21, and is inserted into the upper end side of the intermediate large diameter portion 12 of the valve shaft 10 and the lower end side of the upper small diameter portion 11. It has a setting part 22 and. On the outer circumference of the cylindrical portion 21 of the guide bush 20, one of the screw feed mechanisms 28 that raises and lowers the valve body 14 of the valve shaft 10 with respect to the valve seat 46a of the valve body 40 according to the rotational drive of the rotor 51 is configured. A fixing screw portion (male screw portion) 23 is formed. Further, the lower portion of the cylindrical portion 21 (the portion below the fixing screw portion 23) has a large diameter, and is a fitting portion 27 to the fitting hole 44 of the valve body 40. A lower stopper 25 is screwed and fixed to the fixing screw portion 23 (below the valve shaft holder 30 in the fixing screw portion 23), and the valve shaft holder 30 (that is, the valve shaft holder 30) is fixed to the outer periphery of the lower stopper 25. A fixed stopper body 24 constituting one of the lower stopper mechanisms 29 that regulates the downward movement of the valve shaft 10) connected to the 30) is integrally projected. The upper surface 27a of the fitting portion 27 is a stopper portion that regulates the downward movement of the lower stopper 25 (in other words, defines the lower movement limit position or the lowest 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 ceiling portion 32 through which an insertion hole 32a through which the upper end portion of the valve shaft 10 (upper small diameter portion 11) is inserted is inserted. Have. A movable screw portion (female screw portion) 33 that is screwed with the fixing screw portion 23 of the guide bush 20 to form the screw feed mechanism 28 is formed on the inner circumference of the cylindrical portion 31 of the valve shaft holder 30. A movable stopper body 34 constituting the other side of the lower stopper mechanism 29 is integrally projected from the lower end of the outer circumference of the cylindrical portion 31.

Further, between the terrace surface formed between the upper small diameter portion 11 of the valve shaft 10 and the intermediate large diameter portion 12 and the lower surface of the ceiling portion 32 of the valve shaft holder 30, the upper small diameter of the valve shaft 10 is formed. The valve shaft 10 and the valve shaft holder 30 are urged in a direction away from each other in the elevating direction (axis O direction) so as to be externally inserted into the portion 11, in other words, the valve shaft 10 (valve body 14) is always downward. The compression coil spring 60 urging in the (valve closing direction) is contracted.

The valve body 40 is made of, for example, a metal cylinder such as brass or SUS. The valve body 40 has a valve chamber 40a into which a fluid is introduced and led out, and a first conduit 41a is connected and fixed to a lateral first opening 41 provided on a side portion of the valve chamber 40a by brazing or the like. An insertion hole is inserted into the ceiling of the valve chamber 40a so that the valve shaft 10 (intermediate large diameter portion 12) can move (slide) relative to the axis O and can rotate relative to the axis O. A fitting hole 44 is formed by fitting the lower portion (fitting portion 27) of the guide bush 20 and the guide bush 20 to be mounted and fixed, and a second opening 42 in the vertical direction provided in the lower portion of the valve chamber 40a is provided. 2 The conduit 42a is connected and fixed by brazing or the like. Further, a valve port 46 having a valve seat 46a with which the valve body 14 is brought into contact with and separated from the valve body 14 is formed in a valve seat portion 45 formed of a bottom wall provided between the valve chamber 40a and the second opening 42. ..

As can be clearly seen by referring to FIG. 2 together with FIG. 1, the valve port 46 is the narrowest portion (inner diameter is constant in the ascending / descending direction) formed from the upper side (valve chamber 40a side) and connected to the valve seat 46a. The valve port 46 has the smallest diameter portion) 46s and the enlarged diameter portion 46b formed of a conical base surface which is continuous with the lower side of the narrowest portion 46s and whose inner diameter is continuously increased toward the lower side. ..

The inner diameter (diameter) (φB) of the valve seat 46a (the narrowest portion 46s of the valve opening 46) is designed to be smaller than the lower small diameter portion 13 of the valve shaft 10, and the seating surface portion 14a of the valve body 14 is designed. The diameter is designed to be slightly larger than the outer diameter of the lower end portion (φA1) and the outer diameter of the upper end portion of the curved surface portion 14b (φA2). The outer diameter (φA1) of the lower end portion (tip portion) of the seating surface portion 14a and the outer diameter (φA2) of the upper end portion (base end portion) of the curved surface portion 14b are substantially the same in this example. Specifically, the inner diameter (φB) of the valve seat 46a is 0.005 to 0.015 mm larger than the outer diameter (φA1) of the lower end portion of the seating surface portion 14a of the valve body 14, and the lower end of the seating surface portion 14a. The outer diameter (φA1) of the portion is 0 to 0.015 mm larger than the outer diameter (φA2) of the upper end portion of the curved surface portion 14b.

On the other hand, the flange-shaped plate 47 is fixed to the upper end of the valve body 40 by caulking or the like, and the lower end of the cylindrical can 55 with a ceiling is attached to the stepped portion provided on the outer periphery of the flange-shaped plate 47. It is hermetically sealed by butt welding.

A rotor 51 is rotatably arranged inside the can 55 and outside the guide bush 20 and the valve shaft holder 30, and the yoke 52a, to drive the rotor 51 rotationally outside the can 55, A stator 52 composed of a bobbin 52b, a stator coil 52c, a resin mold cover 52d, and the like is arranged. A plurality of lead terminals 52e are connected to the stator coil 52c, and a plurality of lead wires 52g are connected to these lead terminals 52e via the substrate 52f and arranged in the can 55 by energizing the stator coil 52c. The existing rotor 51 rotates around the axis O.

The rotor 51 arranged in the can 55 is engaged and supported by the valve shaft holder 30, and the valve shaft holder 30 rotates (integrally) with the rotor 51.

Specifically, the rotor 51 has a double pipe configuration including an inner cylinder 51a, an outer cylinder 51b, and a connecting portion 51c that connects the inner cylinder 51a and the outer cylinder 51b at a predetermined angle position around the axis O. A vertical groove 51d extending in the axis O direction (vertical direction) is formed on the inner circumference of the inner cylinder 51a (for example, at an angle interval of 120 degrees around the axis O).

On the other hand, on the outer circumference (upper half portion) of the valve shaft holder 30, a ridge 30a extending in the vertical direction (for example, at an angle interval of 120 degrees around the axis O) is projected, and a lower portion of the ridge 30a is provided. On both sides, upward locking surfaces (not shown) that support the rotor 51 are formed.

The vertical groove 51d of the inner cylinder 51a of the rotor 51 and the ridge 30a of the valve shaft holder 30 are engaged with each other, and the lower surface of the inner cylinder 51a of the rotor 51 and the locking surface of the valve shaft holder 30 are in contact with each other. The rotor 51 is supported and fixed in a state of being aligned with the valve shaft holder 30, and the valve shaft holder 30 is rotated together with the rotor 51 while supporting the rotor 51 in the can 55.

On the upper side of the rotor 51 and the valve shaft holder 30, the relative movement of the valve shaft holder 30 and the rotor 51 in the ascending / descending direction is prevented (in other words, the rotor 51 is pressed downward against the valve shaft holder 30) and the valve is valved. A push nut 71 that is externally fitted and fixed to the upper end of the valve shaft 10 (upper small diameter portion 11) by press fitting, welding, or the like, and the push nut 71 and the rotor 51 in order to connect the shaft 10 and the valve shaft holder 30. A retaining locking member 70 composed of a rotor retainer 72 made of a disk-shaped member having an insertion hole 72a formed in the center of which the upper end portion of the valve shaft 10 is inserted is arranged. ing. That is, the rotor 51 is sandwiched between the valve shaft holder 30 that is urged upward by the urging force of the compression coil spring 60 and the rotor retainer 72. The height (vertical direction) from the upper end of the valve shaft holder 30 to the locking surface is the same as the height (vertical direction) of the inner cylinder 51a of the rotor 51, and the valve shaft holder 30 (ceiling portion 32). ) Is in contact with the lower surface (flat surface) of the rotor retainer 72.

Further, the valve shaft holder 30 moves too much upward with respect to the guide bush 20 to the push nut 71 fixed to the upper end portion of the valve shaft 10, and the fixing screw portion 23 of the guide bush 20 and the valve. In order to prevent the shaft holder 30 from being screwed off from the movable screw portion 33, a return spring 75 made of a coil spring that urges the valve shaft holder 30 toward the guide bush 20 is externally provided.

In the motorized valve 1 having such a configuration, when the rotor 51 is rotated by energizing the stator 52 (stator coil 52c), 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 moved up and down with the valve body 14 by the screw feed 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 causing the valve body 14 to move up and down. The gap (lift amount, valve opening degree) between the valve seat 46a and the valve seat 46a is increased or decreased to adjust the flow rate of a fluid such as a refrigerant (see the flow rate characteristic shown by the solid line in FIG. 3). Further, when the movable stopper body 34 of the valve shaft holder 30 and the fixed stopper body 24 of the lower stopper 25 fixed to the guide bush 20 are in contact with each other and the valve body 14 is in the lowest position (the lift amount of the valve body 14 is increased). (When 0), the valve body 14 (seat surface portion 14a) is seated on the valve seat 46a, and the valve port 46 is closed to a fully closed state, so that the flow of fluid such as refrigerant in the valve port 46 is blocked. (The state shown in FIGS. 1 and 2).

Here, in the present embodiment, a constricted surface portion 14c connecting them is interposed between the seating surface portion 14a and the curved surface portion 14b of the valve body 14. Therefore, the angle R (cutting tool R) can be eliminated from the seating surface portion 14a of the valve body 14, and the outer diameter (φA2) of the curved surface portion 14b (upper end portion) inserted into the valve opening 46 is the valve seat 46a (valve opening 46). It is brought closer to the inner diameter (φB) of the narrowest portion 46s), and the gap between the curved surface portion 14b (upper end portion) and the narrowest portion 46s of the valve opening 46 is extremely reduced.

As described above, in the present embodiment, the constricted surface portion 14c can suppress the occurrence of the angle R on the seating surface portion 14a, and the seating at the angle R as described above can be avoided while keeping the outer diameter of the curved surface portion 14b large. Therefore, for example, compared to the conventional electric valve in which a curved surface portion and a straight portion are connected to the lower side of the seating surface portion, the rising flow rate can be sufficiently reduced while simplifying the management of the rising flow rate, and the controllability in the low flow rate range is effective. Can be improved.

In the above embodiment, the constricted surface portion 14c is provided between the seating surface portion 14a and the curved surface portion 14b of the valve body 14 (in other words, directly below the seating surface portion 14a and directly above the curved surface portion 14b). For example, as shown in FIG. 4, a straight portion 14s made of a cylindrical surface (outer diameter is constant in the elevating direction) may be provided between the constricted surface portion 14c and the curved surface portion 14b of the valve body 14. In the example shown in FIG. 4, a straight portion 14s having substantially the same height as the constricted surface portion 14c (in the vertical direction) is formed directly below the constricted surface portion 14c. In this case, since the portion where the flow rate does not change becomes longer in the low flow rate range (see the flow rate characteristics shown by the dotted line in FIG. 3), the controllability in the low flow rate range is more effective while simplifying the management of the rising flow rate. It is possible to improve to. By performing a necking process in which the portion corresponding to the straight portion 14s of the valve body 14 is recessed, the length of the narrowest portion 46s, which is the shortest distance between the valve port 46 and the valve shaft 10, is shortened, and foreign matter is caught. The risk of getting in can be reduced.

Further, in the above embodiment, the outer diameter (φA1) of the lower end portion of the seating surface portion 14a of the valve body 14 and the outer diameter (φA2) of the upper end portion of the curved surface portion 14b are substantially the same. As shown in A) to (C), the outer diameter (φA2) of the upper end portion of the curved surface portion 14b is larger than the outer diameter (φA1) of the lower end portion of the seating surface portion 14a (in other words, the lower end of the seating surface portion 14a). The outer diameter (φA1) of the portion may be smaller than the outer diameter (φA2) of the upper end portion of the curved surface portion 14b).

In that case, in the example shown in FIG. 5A, a constricted surface portion formed as an annular concave surface (curved surface) with a cross section including the axis O, similar to the above embodiment, between the seating surface portion 14a and the curved surface portion 14b. 14d is provided. Further, in the example shown in FIG. 5B, a cylindrical surface (the outer diameter is constant in the axis O direction) is continuously provided at the lower end portion of the seating surface portion 14a, and the cylindrical surface and the upper end portion of the curved surface portion 14b are , It is connected by a stepped portion (terrace surface) 14ea composed of a surface orthogonal to the axis O, and the outer diameter is narrower than the upper end portion of the curved surface portion 14b by the cylindrical surface and the stepped portion (terrace surface) 14ea. 14e is configured. Further, in the example shown in FIG. 5C, the outer diameter is continuously increased toward the lower side (curved surface portion 14b side) between the seating surface portion 14a and the curved surface portion 14b (the upper end of the curved surface portion 14b). A constricted surface portion 14f made of a conical base surface (with an outer diameter narrower than that of the portion) is provided.

The specific dimensions of the electric valve provided with the valve body 14 having the constricted surface portions 14d, 14e, 14f shown in FIGS. 5 (A), 5 (B), and (C) above will be described as the inner diameter of the valve seat 46a. φB) is 0.005 to 0.095 mm larger than the outer diameter (φA1) of the lower end of the seating surface 14a of the valve body 14, and the outer diameter (φA2) of the upper end of the curved surface 14b is the lower end of the seating surface 14a. It is 0 to 0.08 mm larger than the outer diameter (φA1) of the part.

It goes without saying that any of the motorized valves provided with the valve body 14 having the constricted surface portions 14d, 14e, and 14f can exhibit the same effects as those of the above-described embodiment shown in FIGS. 1 and 2. Further, in a structure in which the outer diameter (φA2) of the upper end portion of the curved surface portion 14b is larger than the outer diameter (φA1) of the lower end portion of the seating surface portion 14a, even if the valve shaft 10 swings in the radial direction, the curved surface portion 14b When the upper end portion of the valve port 46 comes into contact with the inner wall surface of the valve opening 46, the valve shaft 10 does not swing any more in the radial direction, so that the valve seat 46a is surely seated on the seating surface portion 14a. Further, in such a structure, if the outer diameter (φA1) of the lower end portion of the seating surface portion 14a is equal to or less than the outer diameter (φA2) of the upper end portion of the curved surface portion 14b, it must be equal to or less than the inner diameter (φB) of the valve seat 46a. Since the above condition is also satisfied, it becomes easy to control the dimensions (in the radial direction) of the outer diameter (φA1) of the lower end portion of the seating surface portion 14a.

Further, in the above embodiment, the curved surface portion 14b of the valve body 14 has a plurality of steps of inverted truncated cone-shaped tapered surface portions (upper tapered surface portion 14ba and lower tapered surface portion 14bb) in which the control angle is gradually increased toward the tip end side. However, it is not limited to this, and it is an elliptical spherical surface portion whose curvature is continuously increased as it approaches the tip, or an inverted truncated cone-shaped tapered surface portion having one or more stages of the elliptical spherical surface portion. Of course, it may be configured by combining with and the like.

1 Electric valve 10 Valve shaft 14 Valve body 14a Seating surface 14b Curved surface 14ba Upper tapered surface 14bb Lower tapered surface 14c, 14d, 14e, 14f Constricted surface 14s Straight 20 Guide bush 21 Cylindrical 23 Fixed thread (male thread)
28 Thread feed mechanism 29 Lower stopper mechanism 30 Valve shaft holder 33 Movable screw part (female thread part)
40 Valve body 40a Valve chamber 41 1st opening 41a 1st conduit 42 2nd opening 42a 2nd conduit 45 Valve seat part 46 Valve mouth 46a Valve seat 46b Diameter expansion part 46s Narrowest part 47 Collar shape part 50 Stepping motor 51 Rotor 52 Stator 55 Can 60 Compression coil spring 70 Retaining locking member O Axis

Claims (4)

An electric valve including a valve body having a valve chamber and a valve port with a valve seat, and a valve body that changes the flow rate of fluid flowing through the valve port according to a lift amount.
The valve body includes a seating surface portion formed of an inverted conical base surface that is in contact with the valve seat, and a curved surface portion that is inserted into the valve opening and is continuously or stepwise increased as the curvature or control angle approaches the tip. Is provided, and a constricted surface portion having an outer diameter narrower than that of the base end portion of the curved surface portion is provided between the seating surface portion and the curved surface portion.
The inner diameter of the valve seat is larger than the outer diameter of the tip end portion of the seating surface portion of the valve body, and the outer diameter of the tip end portion of the seating surface portion is larger than the outer diameter of the base end portion of the curved surface portion. Electric valve. The electric valve according to claim 1, wherein a straight portion having a constant outer diameter in the elevating direction is further provided between the constricted surface portion and the curved surface portion of the valve body. The electric valve according to claim 1 or 2, wherein the valve port is provided with a narrowest portion formed of a cylindrical surface connected to the valve seat. The motorized valve according to any one of claims 1 to 3, wherein the constricted surface portion is formed of an annular concave surface in a cross section including an axis.

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