CN113418014B

CN113418014B - Electric valve

Info

Publication number: CN113418014B
Application number: CN202110754553.6A
Authority: CN
Inventors: 中川大树
Original assignee: Saginomiya Seisakusho Inc
Current assignee: Saginomiya Seisakusho Inc
Priority date: 2016-09-30
Filing date: 2017-09-28
Publication date: 2023-10-17
Anticipated expiration: 2037-09-28
Also published as: CN113324054B; JP7266639B2; JPWO2018062376A1; JP7462092B2; CN113418014A; JP2023089206A; WO2018062376A1; CN113324054A; CN109715997B; CN109715997A; JP2021152414A; JP6904968B2

Abstract

The application provides an electric valve capable of accurately controlling a minute flow rate in a low opening area. In an electric valve in which a rotational motion of a rotor is converted into a linear motion by a screw coupling of a male screw member and a female screw member, and a valve body housed in a valve body is moved in an axial direction based on the linear motion, the electric valve has a valve seat having a seat portion in which the valve body is seated in a valve-closed state and a valve port into which the valve body is inserted, the valve body includes: a first tapered portion that abuts against the seating portion in the closed valve state; and a second tapered portion located at the front end portion of the first tapered portion, wherein a space having a width wider than a width of a gap formed between the valve port and the second tapered portion is formed between the seat portion and the gap in a state where the first tapered portion is brought into contact with the seat portion, a reduced diameter portion is formed between the first tapered portion and the second tapered portion, and the space is formed between the reduced diameter portion and the valve port in a state where the first tapered portion is brought into contact with the seat portion.

Description

Electric valve

The application is a divisional application; the application number of the parent case is 2017800559633, and the application name is an electric valve.

Technical Field

The present application relates to an electrically operated valve used in a refrigeration cycle system or the like.

Background

Conventionally, an electrically operated valve used in a cabinet air conditioner, an indoor air conditioner, a refrigerator, or the like is known (for example, patent document 1). In this motor-operated valve 100, for example, as shown in fig. 7, when the rotor 103 is rotated by driving the stepping motor, the spool 114 moves in the direction of the central axis L' by the screw feeding action of the male screw 131a and the female screw 121 a. Thereby, the opening/closing valve 121 is adjusted to control the flow rate of the refrigerant flowing in from the pipe joint 111 and flowing out from the pipe joint 112.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 10-148420

Disclosure of Invention

Problems to be solved by the application

However, in the technical field of air conditioners, refrigerators and the like, there is an active study to improve energy saving performance, and there is a background that similar energy saving performance is required for an electric valve used in such a refrigeration cycle system. Here, as the performance of the electric valve, there is a demand for improvement of controllability of a minute flow rate in a low opening region immediately after the valve element is separated from the valve seat, and reduction of variation in the flow rate.

In particular, in an electric valve used in an indoor air conditioner, a small-sized service air conditioner, or the like, it is desirable to reduce the flow rate in the minimum opening degree to a limit in order to control the minute flow rate in the low opening degree region.

In this regard, the following attempts were made: in the above-described electrically operated valve 100, as shown in fig. 8 (a), in the valve element 114, the second tapered portion 114b having an extremely small taper angle (angle of the inclined surface of the tapered portion with respect to the central axis L') is formed between the first tapered portion 114a and the third tapered portion 114c having relatively large angles of seating on the valve seat 120, thereby improving the flow rate control in the low opening region.

Fig. 8 (b) is a graph showing flow rate characteristics in the low opening region of the motor-operated valve 100. In fig. 8 (b), the horizontal axis of the graph indicates the amount of pulse applied to the stepping motor to move the spool 114, and the vertical axis of the graph indicates the flow rate. The origin of the graph indicates the valve-closed state at the time of the 0 pulse. Here, a broken line a in the figure indicates a change in flow rate when the spool 114 is used. In the figure, as a comparative example with the fold line a, as shown in fig. 9, a fold line B showing a change in flow rate when the spool 114' having no second tapered portion 114B formed therein is used is shown.

According to fig. 8 (B), in the broken line B, the flow rate increases in the flow rate region 202 from the rising flow rate region 201 defined by the first tapered portion 114'a to the flow rate region 203 defined by the third tapered portion 114' c, whereas in the broken line a, the flow rate characteristics can be suppressed from rapidly changing in the low opening region by temporarily controlling the degree of increase in the flow rate region 202 by the second tapered portion 114B having a smaller angle after the rising flow rate region 201.

However, in order to improve the controllability of the minute flow rate in the original low opening region, it is necessary to suppress the value of the maximum flow rate X in the upward flow rate region 201 immediately after the valve element 114 is separated from the valve seat 120. In this regard, in the electric valve 100, even if the second tapered portion 114b is provided, this problem cannot be solved.

Here, as shown in fig. 10 (a), it is also considered that the tapered portion 214c of the valve body 214 for flow rate control is seated on the valve seat 220. In this case, as shown in fig. 10 (b), although the flow rate in the upward flow region 210 can be made extremely small, the valve body 214 is difficult to open due to biting into the valve seat 220, and there is a concern that the operability of the valve body 214 is hindered.

As shown in fig. 11 (a), it is also conceivable to reduce the rising flow rate by making the diameter D1 of the boundary between the first tapered portion 314a and the second tapered portion 314b approach the inner diameter D2 of the valve seat 320. However, as shown in an enlarged view in fig. 11 (b), when the boundary between the first tapered portion 314a and the second tapered portion 314b is seated, the second tapered portion 314b for flow rate control is seated due to the machining variation of the valve body 314, and as described above, there is a concern that the valve body 314 bites into the valve seat 320.

Further, since the rounded portion 315 is formed at the boundary at the time of actual machining, when the valve body 314 is seated on the valve seat 320, a portion of the rounded portion 315 may contact the valve seat 320. Since the size, shape, etc. of the rounded portion 315 are likely to vary in processing of the valve body 314, when the rounded portion 315 is in contact with the valve seat 320 during seating, there is a problem in that the rising flow rate characteristics are different from one electrically operated valve to another.

The purpose of the present application is to provide an electrically operated valve that can accurately control a minute flow rate in a low-opening region.

Means for solving the problems

An electric valve according to the present application is an electric valve in which a rotational motion of a rotor is converted into a linear motion by a screw coupling between an external screw member and an internal screw member, and a valve body housed in a valve body is moved in an axial direction based on the linear motion,

comprises a valve seat having a seating portion for seating the valve element in a closed state and a valve port into which the valve element is inserted,

the valve element includes:

a first tapered portion that abuts against the seating portion in a closed state; and

a second tapered portion located at the front end portion of the first tapered portion,

in a state where the first tapered portion is brought into contact with the seating portion, a space having a width wider than a width of a gap formed between the valve port and the second tapered portion is formed between the seating portion and the width of the gap,

a reduced diameter portion is formed between the first tapered portion and the second tapered portion,

the space is formed between the reduced diameter portion and the valve port in a state where the first tapered portion is brought into contact with the seating portion.

In the motor-operated valve according to the present application, the rotation of the rotor is converted into linear motion by the screw coupling of the male screw member and the female screw member, and the stainless valve body housed in the valve body is moved in the axial direction based on the linear motion,

a stainless steel valve seat having a seat portion for seating the valve element in a closed state and a valve port into which the valve element is inserted,

the valve port has an inner peripheral surface parallel to a central axis of the motor-operated valve,

the valve element includes:

a second tapered portion located at the tip end portion and surrounded by the inner peripheral surface in the closed valve state,

a space having a width wider than a gap formed between the valve port and the second tapered portion is formed between the seating portion and the gap in a state where the first tapered portion is brought into contact with the seating portion,

the gap between the inner peripheral surface of the valve port and the second tapered portion is minimized in the gap between the inner peripheral surface of the valve port and the valve body,

a retreating area retreating from the valve core side is formed on the rotor side of the valve port,

the retreating area is a chamfer that expands toward the rotor side.

Thus, the function of the first tapered portion can be limited to the seating function as much as possible, and the flow rate is controlled mainly by the second tapered portion, so that the minute flow rate in the low opening area can be accurately controlled.

Further, the boundary between the first tapered portion and the second tapered portion can be prevented from being seated on the valve port, and the flow rate characteristics at the time of rising are not different for each electric valve, without being affected by the variation in machining of each valve element.

The motor-operated valve of the present application is characterized in that,

in the valve-closed state, the first tapered portion abuts against the rotor-side edge portion of the retreating region as a seating portion,

the space is formed between the receding region and the first tapered portion abutting against the edge portion.

This can avoid the boundary between the first tapered portion and the second tapered portion from being seated on the valve port, and thus can prevent the flow rate characteristics at the time of rising from being different for each electric valve, regardless of the variation in machining of each valve element.

The motor-operated valve of the present application is characterized in that,

the height of the second tapered portion is formed to be higher than the height of the receding region.

Thus, the flow rate can be controlled in a region where the height of the second tapered portion is wider.

The motor-operated valve of the present application is characterized in that,

the retreating area is a chamfer that expands toward the rotor side.

Thus, the flow rate characteristics at the time of rising can be made not to be different for each electric valve without being affected by the variation in processing of each valve element.

The motor-operated valve of the present application is characterized in that,

the taper angle of the taper surface of the first taper portion of the valve body with respect to the center axis is larger than the inclination angle of the chamfer surface with respect to the center axis of the motor-operated valve.

This can accurately prevent the boundary between the first tapered portion and the second tapered portion from being seated on the valve port.

The motor-operated valve of the present application is characterized in that,

the retreating area is a cutout formed on the rotor side of the valve port.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present application, it is possible to provide an electrically operated valve capable of accurately controlling a minute flow rate in a low opening region.

Drawings

Fig. 1 is a cross-sectional view of an electrically operated valve according to an embodiment.

Fig. 2 is an enlarged cross-sectional view of a main portion of the motor-operated valve according to the embodiment.

Fig. 3 is a graph showing flow rate characteristics in a low opening region of the motor-operated valve according to the embodiment.

Fig. 4 is an enlarged cross-sectional view of a main part of a modification of the motor-operated valve of the embodiment.

Fig. 5 is an enlarged cross-sectional view of a main part of a modification of the motor-operated valve of the embodiment.

Fig. 6 is an enlarged cross-sectional view of a main part of a modification of the motor-operated valve of the embodiment.

Fig. 7 is a sectional view of a conventional electrically operated valve.

Fig. 8 is an enlarged cross-sectional view of a main part of a conventional motor-operated valve and a graph showing flow rate characteristics in a low opening region.

Fig. 9 is an enlarged cross-sectional view of a principal part of the virtual motor-operated valve.

Fig. 10 is an enlarged cross-sectional view of a principal part of a virtual motor-operated valve and a graph showing flow rate characteristics in a low opening region.

Fig. 11 is an enlarged cross-sectional view of a principal part of a virtual motor-operated valve and a graph showing flow rate characteristics in a low opening region.

Detailed Description

Hereinafter, an electrically operated valve according to an embodiment of the present application will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing an electrically operated valve 2 according to an embodiment. In this specification, "upper" or "lower" is defined in the state of fig. 1. That is, the rotor 4 is located above the spool 17. In addition, the "height" in the present specification is also defined in the state of fig. 1. That is, "height" indicates the length in the up-down direction in fig. 1.

In the motor-operated valve 2, the valve body 30 is integrally connected by welding or the like to the lower side of the opening side of the non-magnetic cylindrical cup-shaped housing 60.

Here, the valve body 30 is made of metal such as stainless steel, and has the valve chamber 11 therein. Further, a first pipe joint 12 made of stainless steel, copper, or the like, which directly communicates with the valve chamber 11, is fixedly attached to the valve body 30. A valve seat member 30A having a valve port 16 with a circular cross section is provided below and inside the valve body 30. A second pipe joint 15 made of stainless steel, copper, or the like, which communicates with the valve chamber 11 via the valve port 16, is fixedly attached to the valve seat member 30A.

The rotor 4 is rotatably provided in the inner portion Zhou Shouna of the housing 60, and the valve shaft 41 is disposed in a shaft core portion of the rotor 4 via a sleeve member not shown. The valve shaft 41 and the rotor 4 coupled by the sleeve member integrally move in the up-down direction while rotating. Further, an external thread 41a is formed on the outer peripheral surface near the intermediate portion of the valve shaft 41. In the present embodiment, the valve shaft 41 functions as a male screw member.

A stator, not shown, composed of a yoke, a bobbin, a coil, and the like, and a stepping motor composed of a rotor 4 and a stator are disposed on the outer periphery of the housing 60.

A guide support 52 is fixed to the top surface of the housing 60. The guide support 52 has a cylindrical portion 53 and an umbrella-shaped portion 54 formed on the upper end side of the cylindrical portion 53, and in the present embodiment, the entire guide support is integrally formed by press working. Umbrella 54 is formed in substantially the same shape as the top inside of housing 60.

A cylindrical member 65 serving as a guide for the valve shaft 41 is fitted into the cylindrical portion 53 of the guide support 52. The cylindrical member 65 is made of metal, a material of a lubricant containing synthetic resin, or a surface-treated member, and rotatably holds the valve shaft 41.

A valve shaft holder 6 is fixed below the valve shaft 41 so as not to be rotatable relative to the valve body 30, and the valve shaft holder 6 has a function of restraining tilting of the valve shaft 41 while forming a screw joint a with the valve shaft 41 as described later.

The valve shaft holder 6 is fixed to the valve body 30 by welding or the like, and a through hole 6h is formed in the valve shaft holder 6. Further, a female screw 6d is formed downward to a predetermined depth from an upper opening 6g of the valve shaft holder 6. Therefore, in the present embodiment, the valve shaft holder 6 functions as a female screw member. The screw joint a shown in fig. 1 is constituted by an external screw thread 41a formed on the outer periphery of the valve shaft 41 and an internal screw thread 6d formed on the inner periphery of the valve shaft holder 6.

A tubular valve guide 18 is slidably disposed in the through hole 6h of the valve shaft holder 6 below the valve shaft 41. The top 21 side of the valve guide 18 is bent into a substantially right angle by press forming. A through hole 18a is formed in the top 21. A flange portion 41b is also formed below the valve shaft 41.

Here, the valve shaft 41 is inserted into the through hole 18a of the valve guide 18 in a clearance state so as to be rotatable and radially displaceable with respect to the valve guide 18, and the flange portion 41b is disposed in the valve guide 18 so as to be rotatable and radially displaceable with respect to the valve guide 18. The valve shaft 41 is inserted through the through hole 18a, and the upper surface of the flange 41b is disposed so as to face the top 21 of the valve guide 18. Further, the flange 41b has a larger diameter than the through hole 18a of the valve guide 18, thereby preventing the valve shaft 41 from coming off.

The valve shaft 41 and the valve guide 18 are movable in the radial direction, and concentricity with the valve guide 18 and the spool 17 is obtained without requiring a high degree of concentricity mounting accuracy with respect to the arrangement positions of the valve shaft holder 6 and the valve shaft 41.

A washer, not shown, having a through hole formed in the center thereof is disposed between the top portion 21 of the valve guide 18 and the flange portion 41b of the valve shaft 41. The gasket is preferably a metal gasket having a high lubricity (high slipperiness) surface, a high lubricity resin gasket such as a fluororesin, or a metal gasket coated with a high lubricity resin.

The valve guide 18 accommodates a compressed valve spring 27 and a spring seat 35.

The spool 17 is made of stainless steel, brass, or the like, and has a cylindrical rod-like needle portion 17n, a first tapered portion 17a, a second tapered portion 17b, and a third tapered portion 17c. The center axis of the spool 17 is arranged to overlap with the center axis L of the motor-operated valve 2.

Fig. 2 is an enlarged cross-sectional view of a main portion affecting the flow rate characteristics of the motor-operated valve 2. As shown in fig. 2, the valve seat member 30A is formed with a valve seat top surface 30A1, a receding region 99, a valve port 16, an inclined surface 30A2, a rim 19a, an upper rim 16a, and a lower rim 16b.

The valve seat top surface 30A1 is a flat surface that directly contacts the valve chamber 11 on the upper side (rotor 4 side) of the valve seat member 30A. The retreating area 99 is a portion that is positioned between the valve seat top surface 30A1 and the valve port 16 and retreats from the spool 17 side. In the present embodiment, the chamfer 19 as an inclined surface that expands upward is formed in the retreating area 99.

As will be described later, the valve port 16 is a part that directly affects the flow rate determination. The inner peripheral surface of the valve port 16 is arranged parallel to the central axis L of the motor-operated valve 2.

The inclined surface 30A2 is located below the valve port 16, and the inner diameter of the valve seat member 30A is formed to be larger toward the lower side.

The edge 19a is a portion that becomes the upper edge of the chamfer 19, and forms the boundary between the seat top surface 30A1 and the chamfer 19. In the closed valve state, the first tapered portion 17a seats the edge portion 19a as a seating portion on the valve seat member 30A.

The upper edge 16a is an upper edge of the valve port 16 and also serves as a lower edge of the chamfer 19, and forms a boundary between the chamfer 19 and the valve port 16. The lower edge 16b is a portion that becomes the lower edge of the valve port 16, and forms the boundary between the valve port 16 and the inclined surface 30 A2. That is, the valve port 16 is formed between the upper edge 16a and the lower edge 16b.

In addition, the taper angle θ2 (angle of the taper surface with respect to the central axis of the spool 17) of the first taper portion 17a in the spool 17 is formed to be larger than the inclination angle θ1 of the chamfer 19 (inclination angle of the surface of the chamfer 19 with respect to the central axis L of the motor-operated valve 2) (θ1 < θ2). Therefore, a space 87 having a width wider than the width of the gap 66 described later is formed between the first tapered portion 17a and the chamfer 19 in a state where the first tapered portion 17a is in contact with the edge portion 19 a.

This can avoid the rounded portion 59 formed at the boundary between the first tapered portion 17a and the second tapered portion 17b from being seated on the valve seat member 30A, and can prevent the flow rate characteristics at the time of rising from being different for each of the electric valves 2, regardless of the variation in processing of each of the valve elements 17. Here, the rounded portion 59 is a portion that is particularly prone to variations in machining such as size and shape. In addition, the second tapered portion 17b can be prevented from being seated on the valve seat member 30A, and the valve element 17 can be prevented from biting into the valve port 16.

The inclination angle θ1 is preferably an angle of 10 ° or more and 75 ° or less, and the taper angle θ2 is preferably an angle of 12.5 ° or more and 77.5 ° or less.

Further, the rounded portion 59 is located in a range in which the chamfer 19 is formed in the axial direction in the valve-closed state. Specifically, the position of the range of the height H1 of the inclusion chamfer 19 in fig. 2 is formed.

The taper angle of the second tapered portion 17b is a much smaller angle than the taper angle of the first tapered portion 17a, and the outer diameter of the second tapered portion 17b is formed to be slightly smaller downward. The taper angle of the second taper portion 17b is preferably 1.5 ° or more and 10 ° or less with respect to the central axis L of the motor-operated valve 2.

Here, as described above, a third tapered portion 17c is also formed below the second tapered portion 17 b. In the electrically operated valve 2 of the present embodiment, the main flow rate control is performed in the second tapered portion 17b and the third tapered portion 17c, and the second tapered portion 17b is formed below the first tapered portion 17a seated on the valve seat member 30A.

In addition, the height H2 of the second tapered portion 17b is formed to be higher than the height H1 of the chamfer 19 (H1 < H2). Therefore, in the electric valve 2 of the present embodiment, the flow rate can be controlled in the region where the height H2 of the second tapered portion 17b is large.

The taper angle of the third tapered portion 17c is a much smaller angle than the taper angle θ2 of the first tapered portion 17a, but is larger than the taper angle of the second tapered portion 17 b. Here, the outer diameter of the third tapered portion 17c is formed to be tapered so as to decrease downward.

Here, fig. 3 is a graph showing a relationship between a flow rate and a change in an applied amount of a pulse. In fig. 3, the horizontal axis of the graph indicates the amount of pulse applied to the stepper motor to move the spool 17, and the vertical axis of the graph indicates the flow rate. The origin of the graph indicates the valve-closed state at the time of the 0 pulse. The broken line C in the figure shows a change in the flow rate when the spool 17 is used. In the figure, as a comparative example with the fold line C, as shown in fig. 9, a fold line B showing a change in flow rate when the valve body 114' having no second tapered portion 17B formed therein is used is shown.

As shown in fig. 3, when a pulse is applied to the stepping motor of the electric valve 2, the valve element 17 starts to rise when the amount of pulse applied to the electric valve 2 reaches the valve opening point, and the first tapered portion 17a is separated from the upper edge portion 19a of the chamfer 19, which is the seating portion. Here, the flow rate is determined by the minimum width of the gap generated between the valve port 16 and the spool 17. Therefore, the flow rate at the time of rising immediately after the first tapered portion 17a is separated from the edge portion 19a is determined by the gap between the first tapered portion 17a and the edge portion 19a, which is initially the minimum width. The flow rate in the flow rate region 61 increases rapidly although it is temporary.

When the spool 17 is lifted, the gap 66 between the second tapered portion 17b and the valve port 16 is narrower than the gap between the first tapered portion 17a and the edge portion 19a, and the gap 66 becomes the minimum width of the gap generated between the spool 17 and the valve port 16. Accordingly, the flow rate region 62 up to the low opening region during passage of the second tapered portion 17b through the valve port 16 is determined by the width of the gap 66. Here, since the flow rate in the flow rate region 62 is adjusted by the second tapered portion 17b having an extremely small taper angle, the degree of rising is suppressed, and the gap 66 expands and rises gently as the second tapered portion 17b rises.

Further, since the height H2 of the second tapered portion 17b is formed to be higher than the height H1 of the chamfer 19 (H1 < H2), the rapid rise of the flow rate region 61 at the time of rising can be reliably suppressed. The width of the gap 66 is preferably 1 μm or more and 30 μm or less.

According to the electric valve 2 of this embodiment, the function of the first tapered portion 17a is limited to the seating function as much as possible, and the flow rate is controlled mainly by the second tapered portion 17b, so that the minute flow rate in the low opening region can be accurately controlled. Further, since the taper angle θ2 of the first tapered portion 17a is formed at an angle (θ1 < θ2) larger than the taper angle θ1 of the chamfer 19, the boundary between the first tapered portion 17a and the second tapered portion 17b can be prevented from being seated on the valve port 16, and the flow rate characteristics at the time of rising can be made not to be different for each of the motor-operated valves 2, without being affected by the variation in processing of each of the valve elements 17.

In the present embodiment, the case where the inner peripheral surface of the valve port 16 is parallel to the central axis L of the motor-operated valve 2 has been described as an example, but the valve port 16 may be formed such that the inner diameter increases (expands) downward. In this case, the upper edge 16a of the valve port 16 is always close to the second tapered portion 17b or the third tapered portion 17c every time the spool 17 is lifted or lowered, and the flow rate of the flow rate region 62 shown in fig. 3 is controlled by the upper edge 16a. When the spool 17 is lifted, the gap 66 between the upper edge 16a of the valve port 16 and the second tapered portion 17b or the third tapered portion 17c gradually increases, and the flow rate increases.

In the above embodiment, the case where the chamfer 19 is formed on the upper side of the valve port 16 was taken as an example of the retraction region 99, but the retraction region 99 may be a notch. For example, as shown in fig. 4, a notch 79 may be formed in the upper side of the valve port 16. Here, the cutout 79 is formed with an edge 79a, a wall 79c, a bottom 79d, and an upper edge 16a. Through this cutout 79, the upper side of the valve seat member 30A is cut out in a ring shape.

The edge 79a is a portion that becomes an upper edge of the wall 79c, and forms a boundary between the valve seat top surface 30A1 and the cutout 79. In the closed valve state, the first tapered portion 17a seats the edge 79a of the slit 79 as a seating portion. Further, a space 87 having a width wider than the width of the gap 66 is formed between the first tapered portion 17a and the notch 79 in a state where the first tapered portion 17a is brought into contact with the edge 79a between the first tapered portion 17a and the chamfer 19.

The wall 79c is a side wall dividing the outer periphery of the cutout 79, and is disposed parallel to the central axis L of the motor-operated valve 2. The bottom 79d is a portion that defines the bottom surface of the cutout 79, and is perpendicular to the central axis L of the motor-operated valve 2. The wall 79c need not be strictly parallel to the central axis L, but may be slightly inclined. Similarly, the bottom 79d need not be strictly orthogonal to the central axis L, and may be slightly inclined.

The upper edge 16a is a portion that is an upper edge of the valve port 16 and is a portion of the edge on the side of the valve body 17 that forms the bottom 79d, and defines a boundary between the slit 79 and the valve port 16.

This also prevents the boundary between the first tapered portion 17a and the second tapered portion 17b from being seated on the valve port 16, and thus the flow rate characteristics at the time of rising can be prevented from being deviated for each of the electrically operated valves 2. In addition, the second taper 17b can accurately control the minute flow rate in the low opening region. In addition, since the height H2 of the second tapered portion 17b is formed to be higher than the height H3 of the slit 79 (H3 < H2), the flow rate can be controlled in a region where the height H2 of the second tapered portion 17b is wider.

In the above embodiment, as shown in fig. 5, the reduced diameter portion 89 may be provided between the first tapered portion 17a and the second tapered portion 17 b. In this case, since the boundary between the first tapered portion 17a and the second tapered portion 17b is partially recessed from the surface of the valve body 17, even when the first tapered portion 17a is seated on the valve seat member 30A, a space 87 having a width wider than the width of the gap 66 is formed between the first tapered portion 17a and the valve port 16. This also prevents the boundary between the first tapered portion 17a and the second tapered portion 17b from being seated on the valve port 16, and thus the flow rate characteristics at the time of rising can be prevented from being deviated for each of the electrically operated valves 2. In addition, the second taper portion 17b can accurately control the minute flow rate in the low opening region.

In the above embodiment, the case where the second tapered portion 17b has a very small taper angle substantially parallel to the central axis L was described as an example, but as shown in fig. 6, the second tapered portion 17b may have a predetermined taper angle α. In this case, the upper edge 16a of the valve port 16 is always close to the second tapered portion 17b or the third tapered portion 17c every time the spool 17 is lifted or lowered, and the main flow rate control is performed by the upper edge 16a. When the valve body 17 is lifted, the gap 66 between the upper edge 16a of the valve port 16 and the second tapered portion 17b or the third tapered portion 17c gradually increases, and the flow rate increases.

The taper angle α shown in fig. 6 is preferably an angle of 1 ° or more and 30 ° or less.

In the above embodiment, the case where the spool 17 has the third tapered portion 17c has been described as an example, but the spool 17 may not necessarily have the third tapered portion 17c. In the above embodiment, the spool 17 may have tapered portions other than the first tapered portion 17a, the second tapered portion 17b, and the third tapered portion 17c.

The electric valve 2 of the present embodiment is used as an electronic expansion valve provided between a condenser and an evaporator of a refrigeration cycle, for example.

Description of symbols

2-electric valve, 4-rotor, 6-valve shaft holder, 6 d-female screw, 16-valve port, 16 a-upper edge portion, 16 b-lower edge portion, 17-spool, 17 a-first tapered portion, 17 b-second tapered portion, 17 c-third tapered portion, 19-chamfer, 19 a-edge portion, 30A-valve seat member, 66-gap, 79-cutout, 79 a-edge portion, 79 c-wall portion, 79 d-bottom portion, 89-reduced diameter portion, 87-space, 99-back region.

Claims

1. An electric valve in which a rotational motion of a rotor is converted into a linear motion by a screw coupling of a male screw member and a female screw member, and a valve body accommodated in a valve body is moved in an axial direction based on the linear motion,

comprises a valve seat having a seat portion for seating the valve element in a closed state and a valve port into which the valve element is inserted,

the valve element includes:

in a state where the first tapered portion is brought into contact with the seating portion, a space having a width wider than a width of a gap formed between the valve port and the second tapered portion is formed at a position between the seating portion and the gap,

the space formed between the diameter-reduced portion and the valve port is surrounded by an inner peripheral surface of the valve port in a state where the first tapered portion is brought into contact with the seat portion, and a taper angle of the tapered surface of the second tapered portion with respect to a central axis of the valve body is smaller than a taper angle of the tapered surface of the first tapered portion with respect to the central axis of the valve body.

2. The electrically operated valve as set forth in claim 1, wherein,

when the valve body is lifted, a gap between the second tapered portion and the valve port becomes a minimum width of a gap generated between the valve body and the valve port.

3. The electrically operated valve as set forth in claim 1, wherein,

the valve port has a side surface parallel to the axial direction on the seating portion side,

the valve seat has an inclined surface that expands in a direction away from the seating portion on a side of the valve port opposite to the seating portion.

4. The electrically operated valve as set forth in claim 3, wherein,

the second tapered portion protrudes from a lower end of the valve port in a state where the first tapered portion is seated on the seating portion.

5. The electrically operated valve as set forth in claim 1, wherein,

the reduced diameter portion is disposed adjacent to the second tapered portion.

6. The electrically operated valve as set forth in claim 1, wherein,

the second tapered portion is provided with a third tapered portion located at a distal end of the second tapered portion.

7. An electric valve in which a rotational movement of a rotor is converted into a linear movement by a screw coupling of a male screw member and a female screw member, and a stainless valve body housed in a valve body is moved in an axial direction based on the linear movement,

the valve element includes:

the retreating area is a chamfer that expands toward the rotor side,

in a state where the first tapered portion is brought into contact with the seat portion, an end portion of the first tapered portion on the second tapered portion side is surrounded by the chamfer connecting the seat portion and the valve port,

the valve body includes a cylindrical rod portion having an outer diameter larger than the diameter of the seating portion, the cylindrical rod portion being provided on the rotor side of the first tapered portion.

8. The electrically operated valve as set forth in claim 7, wherein,

the valve body is provided with a first tapered portion and a second tapered portion.

9. The electrically operated valve as set forth in claim 7, wherein,

the valve body is provided with a valve chamber inside.

10. The electrically operated valve as set forth in claim 9, wherein,

the valve body includes a first pipe joint communicating with the valve chamber.

11. The electrically operated valve as set forth in claim 10, wherein,

the lower end of the inner surface of the first pipe joint is located at a position higher than a position where the first tapered portion and the seating portion are abutted in the valve-closed state.

12. The electrically operated valve as set forth in claim 10, wherein,

the first pipe joint is made of stainless steel or copper.

13. The electrically operated valve as set forth in claim 10, wherein,

the end portion of the first pipe joint on the valve chamber side protrudes into the valve chamber.

14. The electrically operated valve as set forth in claim 9, wherein,

the valve seat has a second pipe joint communicating with the valve chamber via the valve port,

the second pipe joint is made of stainless steel or copper.

15. The electrically operated valve as set forth in claim 9, wherein,

the valve chamber has an inner wall parallel to a central axis of the valve body.

16. The electrically operated valve as set forth in claim 15, wherein,

the valve chamber has an opening on the rotor side and the inner wall is erected from the bottom side of the valve chamber,

the inner wall is parallel to the central axis of the valve body from the bottom side to the opening.

17. The electrically operated valve as set forth in claim 7, wherein,

18. The electrically operated valve as set forth in claim 17, wherein,

the maximum inner diameter of the inclined surface is larger than the outer diameter of the cylindrical rod portion of the valve body.

19. The electrically operated valve as set forth in claim 7, wherein,

the valve further includes a screw feed mechanism including a female screw member fixed to the valve body and a male screw integrally moved in an axial direction with the rotor.

20. The electrically operated valve as set forth in claim 7, wherein,

the valve body further includes a third tapered portion located at a distal end portion of the second tapered portion,

and the second tapered portion is formed continuously with the first tapered portion.

21. The electrically operated valve as set forth in claim 20, wherein,

the taper angle of the taper surface of the third taper portion with respect to the central axis of the valve body is smaller than the taper angle of the taper surface of the first taper portion with respect to the central axis of the valve body.