阅读说明：本技术 电动阀及其组装方法 (Electric valve and assembling method thereof ) 是由 吉田龙也 矢泽将志 于 2016-04-08 设计创作，主要内容包括：本发明提供一种电动阀及其组装方法,该电动阀结构简单,且能够抑制原点位置上的阀芯与阀座部之间形成的间隙的尺寸偏差。使下部止动件(25)以能够相对旋转的方式螺合于导衬(20)并配置在规定位置,在通过下部止动机构(29)使阀轴支架(30)位于最下移动位置时,使阀芯(14)与阀座部(46a)抵接,经由压缩螺旋弹簧(60)连结固定阀轴(10)与阀轴支架(30),之后,使位于规定位置的下部止动件(25)相对于导衬(20)向开阀方向旋转规定旋转角度而将下部止动件(25)以不能相对旋转的方式连结于该导衬。(The invention provides an electric valve and an assembling method thereof, the electric valve has simple structure and can restrain the size deviation of a gap formed between a valve core and a valve seat part at an original position. A lower stopper (25) is relatively rotatably screwed to a guide bush (20) and disposed at a predetermined position, and when a valve shaft holder (30) is positioned at the lowermost movement position by a lower stopper mechanism (29), a valve body (14) is brought into contact with a valve seat portion (46a), and the valve shaft (10) and the valve shaft holder (30) are coupled and fixed via a compression coil spring (60), and thereafter, the lower stopper (25) positioned at the predetermined position is rotated in the valve opening direction by a predetermined rotation angle with respect to the guide bush (20), and the lower stopper (25) is relatively non-rotatably coupled to the guide bush.)

1. An electrically operated valve, comprising:

a valve shaft provided with a valve element at a lower end portion thereof;

a guide bush having a cylindrical portion, the valve shaft being inserted into the cylindrical portion in a state of being relatively movable in an axial direction and relatively rotatable;

a valve main body having a valve seat portion that is in contact with or separated from the valve body, and to which the guide bush is attached and fixed;

a valve shaft holder having a cylindrical portion into which the guide bush is inserted and a top portion through which an insertion hole is formed, the valve shaft holder being coupled and fixed to the valve shaft, the insertion hole having an upper end portion through which the valve shaft is inserted;

a biasing member that is attached between the valve shaft and the valve shaft holder and biases the valve body in a valve closing direction;

a motor having a rotor and a stator for rotating the valve shaft holder relative to the guide bush;

a screw feed mechanism including the guide bush and the valve shaft holder, for raising and lowering the valve body of the valve shaft relative to the valve seat portion in accordance with rotational driving of the rotor:

a lower stopper mechanism for restricting rotation and downward movement of the valve shaft holder, the lower stopper mechanism including a fixed stopper body provided to a lower stopper, the lower stopper being screwed to the guide bush, and a movable stopper body provided to the valve shaft holder; and

a pressing member that prevents relative rotation of the lower stopper with respect to the guide bush.

2. Electrically operated valve according to claim 1,

the pressing member is fixed to the valve main body.

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

when the valve shaft holder is located at the lowermost movement position and the valve body is located at the lowermost position by the lower stopper mechanism, a gap is formed between the valve body and the valve seat portion.

Technical Field

The present invention relates to an electrically operated valve used as a flow rate control valve or the like in a refrigeration cycle installed in an air conditioner, a refrigerator, or the like, and more particularly, to an electrically operated valve of a non-valve-closing type in which a gap of a predetermined size is formed between a valve body and a valve seat portion when the valve body is at a lowermost position (normally, in a fully closed state), and an assembling method thereof.

Background

As such a motor-operated valve, for example, a structure is known (for example, see patent document 1) including: a valve shaft; a guide rod having a cylindrical portion into which the valve shaft is inserted; a cylindrical valve holder which is held and fixed to a lower end portion of the valve shaft and is inserted into the guide rod; a valve body inserted into the valve holder in a state of being relatively movable and rotatable in an axial direction with respect to the valve shaft, biased downward by compressing a coil spring installed between the valve body and the valve shaft, and locked by the valve holder in a retaining manner; a valve main body having a valve seat portion that contacts with or separates from the valve body, and to which the guide rod is attached and fixed; a housing coupled to the valve body; a rotor disposed on an inner periphery of the housing; a rotor holder that couples the rotor and the valve shaft via a coupling member that is fitted and fixed to an upper end of the valve shaft; a recess formed in the rotor holder for engaging with an engaging portion provided in the rotor; a stator disposed on an outer periphery of the housing to rotationally drive the rotor; an internal thread member disposed on an inner periphery of the cylindrical portion of the guide bar; a screw feed mechanism which is configured by a fixed screw portion formed on an inner periphery of the female screw member and a movable screw portion formed on an outer periphery of the valve shaft, and which is used for bringing the valve body into contact with or separating the valve seat portion from the valve seat portion; and a stopper mechanism disposed on an outer periphery of the cylindrical portion of the guide rod and restricting rotation and up-and-down movement of the rotor, the stopper mechanism being composed of a spiral fixed stopper having an upper locking portion and a lower locking portion, and a ring-shaped or spiral slider provided with a 1 st abutting portion abutting and locked to the upper locking portion and a 2 nd abutting portion abutting and locked to the lower locking portion, and assembled to a spiral portion of the fixed stopper, the 1 st abutting portion being pushed by a pushing portion provided to the rotor when the rotor rotates, the slider moving up and down while rotating until the 1 st abutting portion abuts to the upper locking portion or the 2 nd abutting portion abuts to the lower locking portion, at an origin position where the 2 nd abutting portion of the slider abuts to the lower locking portion and is stopped, a gap of a predetermined size is formed between the valve body and the valve seat portion.

In the air conditioner using the motor-operated valve having the above-described configuration, even when the valve element is located at the lowermost position (normally in the fully closed state), a gap of a predetermined size is formed between the valve element and the valve seat portion, and therefore, for example, when the dehumidification operation is performed in late night, the motor-operated valve can be operated in a state in which the amount of refrigerant is throttled without being brought into the fully closed state, and occurrence of operating noise caused by opening/closing of the motor-operated valve can be suppressed. In addition, in the motor-operated valve having the above-described configuration, there is an advantage that the valve body can be reliably prevented from biting into the seat portion, as compared with a normal closed-valve type motor-operated valve.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to provide an electrically operated valve capable of suppressing dimensional variation of a gap formed between a valve body and a valve seat portion at an origin position with a simple configuration, and an assembling method thereof.

In order to solve the above problem, an electrically operated valve according to the present invention includes: a valve shaft provided with a valve element at a lower end portion thereof; a guide bush having a cylindrical portion, the valve shaft being inserted into the cylindrical portion in a state of being relatively movable in an axial direction and relatively rotatable; a valve main body having a valve seat portion that is in contact with or separated from the valve body, and to which the guide bush is attached and fixed; a valve shaft holder having a cylindrical portion into which the guide bush is inserted and a top portion through which an insertion hole is formed, the valve shaft holder being coupled and fixed to the valve shaft, the insertion hole having an upper end portion through which the valve shaft is inserted; a biasing member that is attached between the valve shaft and the valve shaft holder and biases the valve body in a valve closing direction; a motor having a rotor and a stator for rotating the valve shaft holder relative to the guide bush; a screw feed mechanism including a fixed screw portion formed on an outer periphery of the guide bush and a movable screw portion formed on an inner periphery of the valve shaft holder, the screw feed mechanism being configured to raise and lower the valve body of the valve shaft relative to the valve seat portion in accordance with rotational driving of the rotor; and a lower stopper mechanism configured to restrict rotation and downward movement of the valve shaft holder, the lower stopper mechanism including a fixed stopper provided to a lower stopper having a female screw portion screwed to the fixed screw portion of the guide bush, and a movable stopper provided to the valve shaft holder, the movable stopper forming a gap between the valve body and the valve seat portion when the valve body is at a lowermost position, the lower stopper mechanism being configured to restrict rotation and downward movement of the valve shaft holder, the lower stopper mechanism being characterized in that dimensions and shapes of respective portions are designed so as to be able to obtain a seated state and a separated state, the seated state being: the lower stopper is relatively rotatably screwed to the guide bush and disposed at a predetermined position, and the valve body abuts against the valve seat portion when the valve shaft support is located at a lowermost movement position by the lower stopper mechanism; the separation state is: when the lower stopper at the predetermined position is connected to the guide bush so as to be relatively non-rotatable by rotating the lower stopper by a predetermined rotation angle in a valve opening direction with respect to the guide bush, the clearance having a dimension in a lifting direction defined by p × θ/360 is formed between the valve body and the valve seat portion, where p is a pitch of the female screw portion and θ is the predetermined rotation angle when the valve shaft holder is at the lowermost movement position by the lower stopper mechanism.

Preferably, in the separated state, the lower stopper is directly engaged with the guide bush and fixedly coupled thereto.

Further preferably, in the separated state, the lower stopper is coupled to the guide bush via a pressing member that prevents relative rotation of the lower stopper with respect to the guide bush.

Further preferably, the pressing member is joined to the guide bush or the valve main body and fixed.

Further preferably, the guide bush is provided with a stopper portion for restricting downward movement of the lower stopper with respect to the guide bush, and the predetermined position is a position at which the lower stopper abuts against the stopper portion.

Further preferably, the stopper portion is provided on a lower side of the lower stopper in the guide bush or the fixed screw portion of the guide bush.

Further preferably, in the separated state, the lower stopper is brought into contact with or separated from the stopper portion.

The present invention provides an assembling method of an electric valve, the electric valve comprises: a valve shaft provided with a valve element at a lower end portion thereof;

a guide bush having a cylindrical portion, the valve shaft being inserted into the cylindrical portion in a state of being relatively movable in an axial direction and relatively rotatable; a valve main body having a valve seat portion that is in contact with or separated from the valve body, and to which the guide bush is attached and fixed; a valve shaft holder having a cylindrical portion into which the guide bush is inserted and a top portion through which an insertion hole is formed, the valve shaft holder being coupled and fixed to the valve shaft, the insertion hole having an upper end portion through which the valve shaft is inserted; a biasing member that is attached between the valve shaft and the valve shaft holder and biases the valve body in a valve closing direction; a motor having a rotor and a stator for rotating the valve shaft holder relative to the guide bush; a screw feed mechanism including a fixed screw portion formed on an outer periphery of the guide bush and a movable screw portion formed on an inner periphery of the valve shaft holder, the screw feed mechanism being configured to raise and lower the valve body of the valve shaft relative to the valve seat portion in accordance with rotational driving of the rotor; and a lower stopper mechanism configured to restrict rotation and downward movement of the valve shaft holder, the lower stopper mechanism including a fixed stopper provided to a lower stopper having a female screw portion screwed to the fixed screw portion of the guide bush, and a movable stopper provided to the valve shaft holder, the movable stopper mechanism forming a gap between the valve body and the valve seat portion when the valve body is at a lowermost position, the assembling method including: a valve shaft holder that is provided on the valve seat portion, and that is configured to be coupled to the valve shaft by a valve shaft support that is provided on the valve seat portion, and that is configured to be coupled to the valve shaft holder by a valve shaft support that is provided on the valve shaft holder; connecting and fixing the valve shaft and the valve shaft bracket; and rotating the lower stopper at the predetermined position by a predetermined rotation angle in a valve opening direction with respect to the guide bush to couple the lower stopper to the guide bush so as not to be relatively rotatable.

Effects of the invention

According to the present invention, the lower stopper having the female screw portion screwed to the fixed screw portion of the guide bush is rotated in the valve opening direction with respect to the guide bush, and then the lower stopper is coupled to the guide bush so as to be relatively non-rotatable, thereby defining the lowermost position of the valve body, in other words, the gap between the valve body and the valve seat portion when the valve body is located at the lowermost position. That is, since the dimensional accuracy of the gap between the valve body and the valve seat portion at the origin position is substantially determined by the dimensional accuracy of the female screw portion of the lower stopper constituting the lower stopper mechanism and the fixed screw portion of the guide bush, the dimensional variation of the gap can be suppressed as compared with a conventional motor-operated valve in which the dimensional accuracy of the gap is determined by the component accuracy of a component having a complicated shape such as the valve body and the valve body, and thus, the controllability of the flow rate of the fluid (refrigerant) in the low flow rate region can be improved.

Drawings

Fig. 1 is a longitudinal sectional view showing a 1 st embodiment of an electrically operated valve according to the present invention.

Fig. 2 is a diagram for explaining a process of extending an origin position (a lowermost position) of a valve body in an assembling process of the motor-operated valve shown in fig. 1, in which (a) is a vertical sectional view showing a seated state and (B) is a vertical sectional view showing a separated state.

Fig. 3 is a plan view and a partially enlarged vertical cross-sectional view for explaining a process of rotating the lower stopper with respect to the guide bush in the origin position extension process shown in fig. 2.

Fig. 4 is a partially enlarged vertical cross-sectional view showing another example of a stopper portion of the motor-operated valve shown in fig. 1.

Fig. 5 is a diagram showing flow rate characteristics of the motor-operated valve shown in fig. 1.

Fig. 6 is a longitudinal sectional view showing a motor-operated valve 2 according to the present invention.

Fig. 7 is a view showing a stopper pressing member of the electric valve shown in fig. 6, in which (a) is a perspective view and (B) is a plan view.

Fig. 8 is a diagram for explaining a process of extending the origin position (the lowermost position) of the valve body in the assembling process of the motor-operated valve shown in fig. 6, in which (a) is a perspective view showing a state in which the stopper presser is attached in the seated state, and (B) is a perspective view showing a state in which the stopper presser and the lower stopper are rotated from (a).

Description of the symbols

1. 2 electric valve

10 valve shaft

14 valve core

20 guide bush

21 cylindrical part

23 fixed thread part (external thread part)

24 fixed stop body

25 lower stop

26 internal screw thread part

27 fitting part

27 stop part (upper surface of the fitting part)

28 screw thread feeding mechanism

29 lower stop mechanism

30 valve shaft bracket

33 Movable screw part (internal screw part)

34 Movable stop body

35 stop pressing piece (pressing component)

40 valve body

40a valve chamber

41 1 st opening

41a 1 st catheter

42 nd 2 nd opening

42a 2 nd catheter

43 insertion hole

44 fitting hole

45 bottom wall

46 valve port orifice

46a valve seat portion

47 Flange shaped part

50 stepping motor

51 rotor

52 stator

55 casing

60 compression coil spring (force application component)

70 locking part for preventing falling

71 bushing nut

72 rotor pressing piece

0 axis

Detailed Description

Hereinafter, embodiments of the motor-operated valve according to the present invention will be described with reference to the drawings. In the drawings, gaps formed between members, separation distances between members, and the like are exaggerated for easy understanding of the invention, and the drawings are also exaggerated for convenience. In the present specification, the expressions indicating the positions and directions such as up, down, left, and right are based on the directional arrows in fig. 1 and 6, and do not indicate the positions and directions in the actual use state.

[ embodiment 1 ]

Fig. 1 is a longitudinal sectional view showing a 1 st embodiment of an electrically operated valve according to the present invention.

The motor-operated valve 1 of the illustrated embodiment mainly includes a valve shaft 10, a guide bush 20, a valve shaft holder 30, a valve body 40, a housing 55, a stepping motor 50 including a rotor 51 and a stator 52, a compression coil spring (biasing member) 60, a retaining engagement member 70, a screw feed mechanism 28, and a lower stopper mechanism 29.

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 stepped reverse-conical valve element 14 is integrally formed at the lower end of the lower small diameter portion 13.

The guide bush 20 has a cylindrical portion 21 and an extension portion 22, the valve shaft 10 (the intermediate large diameter portion 12) is inserted into the cylindrical portion 21 so as to be 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 portion of the cylindrical portion 21, the inner diameter of the extension portion 22 is larger than the inner diameter of the cylindrical portion 21, and 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 are inserted into the extension portion 22. A fixed screw portion (male screw portion) 23 is formed on the outer periphery of the cylindrical portion 21 of the guide bush 20, and the fixed screw portion 23 constitutes one side of a screw feed mechanism 28 that raises and lowers the valve body 14 of the valve shaft 10 with respect to the valve seat portion 46a of the valve main body 40 in accordance with the rotational drive of the rotor 51. The lower portion of the cylindrical portion 21 (the portion below the fixed threaded portion 23) is formed to have a large diameter, and is formed as a fitting portion 27 that is fitted into the fitting hole 44 of the valve main body 40. The lower stopper 25 is screwed to the fixed screw portion 23 (below the valve shaft holder 30) with a predetermined gap h from the upper surface 27a of the fitting portion 27, and a fixed stopper body 24 is integrally projected from the outer periphery of the lower stopper 25, and the fixed stopper body 24 constitutes one of lower stopper mechanisms 29 that regulate the rotation and downward movement of the valve shaft holder 30. As will be described later in detail, in the present embodiment, the upper surface 27a of the fitting portion 27 is formed as a stopper portion that restricts downward movement of the lower stopper 25 (in other words, defines a downward movement limit position and defines the position of the lower stopper 25 in the seated state).

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

A compression coil spring (urging member) 60 is compression-mounted between a land surface formed between the upper small diameter portion 11 and the intermediate large diameter portion 12 of the valve shaft 10 and a lower surface of the top portion 32 of the valve shaft holder 30 so as to be inserted into the upper small diameter portion 11 of the valve shaft 10, and the compression coil spring 60 urges the valve shaft 10 and the valve shaft holder 30 in a direction separating from each other in the vertical direction (the direction of the axis O), in other words, the valve shaft 10 (the valve body 14) in a downward direction (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 therein, a 1 st pipe 41a is fixedly coupled to a 1 st opening 41 provided in a side portion of the valve chamber 40a by brazing or the like, an insertion hole 43 and a fitting hole 44 are formed in a top portion of the valve chamber 40a, the valve shaft 10 (the intermediate large diameter portion 12 thereof) is inserted into the insertion hole 43 in a state of being relatively movable (slidable) in the axis 0 direction and relatively rotatable about the axis O, the fitting hole 44 is fixedly coupled to a lower end portion of (the cylindrical portion 21 of) the guide bush 20, a 2 nd pipe 42a is fixedly coupled to a 2 nd opening 42 provided in a lower portion of the valve chamber 40a in a longitudinal direction by brazing or the like, a port orifice 46 having a valve seat portion 46a that is in contact with or separated from the valve body 14 is formed in a bottom wall 45 between the valve chamber 40a and the 2 nd opening 42.

A flange-like plate 47 is fastened to an upper end portion of the valve body 40 by caulking or the like, and a lower end portion of a cylindrical housing 55 with a top is butt-welded to a stepped portion provided on an outer periphery of the flange-like plate 47.

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 rotatably 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 axis 0 direction (vertical direction) are formed in the inner circumference of the inner tube 51a (for example, at angular intervals of 120 degrees about the axis O).

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

The rotor 51 is supported and fixed in a state of being aligned with the valve shaft holder 30 by engaging the vertical groove 5ld of the inner cylinder 51a of the rotor 51 with the ridge 30a of the valve shaft holder 30 and bringing the lower surface of the inner cylinder 51a of the rotor 51 into contact with the locking surface of the valve shaft holder 30, and the valve shaft holder 30 supports the rotor 51 in the housing 55 and rotates together with the rotor 51.

A slip-off preventing engagement member 70 including a bush nut 71 and a rotor pressing member 72 is disposed above the rotor 51 and the valve shaft holder 30, the bush nut 71 is externally fitted and fixed to an upper end portion of (the upper small diameter portion 11 of) the valve shaft 10 by press-fitting, welding, or the like, so as to connect the valve shaft 10 and the valve shaft holder 30 together while preventing relative movement of the valve shaft holder 30 and the rotor 51 in the vertical direction (in other words, the rotor 51 is pushed downward with respect to the valve shaft holder 30), and the rotor pressing member 72 is formed of a disk-shaped member disposed between the bush nut 71 and the rotor 51 and having a through hole 72a formed at the center thereof for inserting the upper end portion of the valve shaft 10. 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 engagement 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 holder 72.

Further, a return spring 75 formed of a coil spring for biasing the valve shaft holder 30 toward the guide bush 20 is externally attached to the bush nut 71 fixed to the upper end portion of the valve shaft 10, so as to prevent: during operation, the valve shaft holder 30 excessively moves upward relative to the guide bush 20, and the fixed screw portion 23 of the guide bush 20 is disengaged from the movable screw portion 33 of the valve shaft holder 30 by screwing.

In the motor-operated valve 1, for example, in order to prevent the valve element 14 from biting into the valve seat portion 46a and to ensure controllability in a low flow rate region, a gap of a predetermined size (a gap having a dimension H in the ascending/descending direction) is formed between the valve element 14 and the valve seat portion 46a when the valve element 14 is located at the lowermost position (the origin position).

The assembly process of the motor-operated valve 1, particularly the process of extending the origin position (the lowermost position) of the valve element 14, is described in detail with reference to fig. 2, and first, the valve shaft 10, the guide bush 20, the lower stopper 25, the compression coil spring 60, the valve shaft holder 30, the rotor 51, the valve body 40, and the like are assembled. At this time, the lower stopper 25 is rotatably screwed to the guide bush 20. In this stage, the lower stopper 25 may be disposed in contact with the stopper 27a of the guide bush 20, or may be disposed at a distance from the stopper 27 a. Next, the valve shaft holder 30, the rotor 51, and the valve shaft 10 are lowered while being rotated 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 until the valve body 14 provided at the lower end portion of the valve shaft 10 abuts (is seated on) the valve seat portion 46a, the compression coil spring 60 is slightly compressed, the movable stopper body 34 of the valve shaft holder 30 abuts the fixed stopper body 24 of the lower stopper 25, and (the lower surface of) the lower stopper 25 abuts the stopper portion 27a of the guide bush 20. In the state where the valve shaft holder 30 is disposed at the lowermost position in this manner, the rotor holder 72 is fitted into the upper end portion of the valve shaft 10, and the bushing nut 71 is externally fitted and fixed by press fitting, welding, or the like (seated state, see fig. 2 a).

Next, from the seated state, the assembly in which the valve shaft 10, the valve shaft holder 30, the rotor 51, the retaining locking member 70 (the bushing nut 71 and the rotor retainer 72), and the like are integrated is lifted up and removed from the guide bush 20 by the screw feed mechanism 28 while being rotated, and thereafter, the lower stopper 25 is rotated by a predetermined rotation angle in a valve opening direction (counterclockwise rotation in a plan view in the illustrated example) with respect to the guide bush 20. Then, the lower stopper 25 is fixed to (the fixed screw portion 23 of) the guide bush 20 by welding, adhesion, or the like so as not to be relatively rotatable, and thereafter, the assembly is assembled to the guide bush 20 again by the screw feed mechanism 28. Accordingly, since the position of the fixed stopper body 24 of the lower stopper 25 with respect to the guide bush 20 is changed, even when the movable stopper body 34 of the valve shaft holder 30 abuts against the fixed stopper body 24 of the lower stopper 25 and the valve shaft holder 30 is located at the lowermost position, a gap (a gap having a dimension H in the lifting direction) of a predetermined size is formed between the valve body 14 and the valve seat portion 46a (separated state, see fig. 2B). Further, the description has been given of the structure in which the assembly is lifted up and removed from the guide bush 20, the lower stopper 25 is rotated by a predetermined rotation angle in the valve opening direction with respect to the guide bush 20, and the lower stopper 25 is connected and fixed to the guide bush 20 by welding, adhesion, or the like so as not to be relatively rotatable, but the assembly does not need to be removed from the guide bush 20 as long as: by simply raising the assembly relative to the guide bush 20, the lower stopper 25 can be rotated by a predetermined rotation angle in the valve opening direction relative to the guide bush 20, and a gap can be formed to such an extent that the lower stopper 25 can be fixed to the guide bush 20 by welding, adhesion, or the like so as not to be relatively rotatable.

In addition, when a backlash-free (backlash-free) type screw portion is employed for the female screw portion 26 of the lower stopper 25 and the fixed screw portion (male screw portion) 23 of the guide bush 20, the dimension H in the lifting direction of the clearance formed between the valve body 14 and the valve seat portion 46a and the clearance H between (the lower surface of) the lower stopper 25 and the stopper portion 27a of the guide bush 20 coincide or substantially coincide. However, in general, a backlash (play or looseness) is provided at the threaded portion. Therefore, when the origin position of the valve element 14 is extended by rotating (loosening) the lower stopper 25 in the valve opening direction after the lower stopper 25 is brought into contact with the stopper portion 27a of the guide bush 20 and tightened as in the above-described embodiment, the dimension H does not necessarily coincide with the gap H because the lower stopper 25 is rotated while being kept in contact with the stopper portion 27a of the guide bush 20 (i.e., without being raised) at the initial stage of the rotation.

Specifically, as can be understood from fig. 3, assuming that the rotational angle of the backlash amount between the female screw portion 26 of the lower stopper 25 and the fixed screw portion 23 of the guide bush 20 is θ b ° (about 180 ° in the example of the figure), when the lower stopper 25 is rotated (loosened) in the valve opening direction from a state in which the lower stopper 25 is brought into contact with and tightened against the stopper 27a of the guide bush 20 (in this state, the upper surface side of the female screw portion 26 of the lower stopper 25 is brought into contact with the lower surface side of the fixed screw portion 23 of the guide bush 20) in the above-described origin position extending step, (the lower stopper 25 continues to be brought into contact with (the lower surface of) the stopper 27a of the guide bush 20 by its own weight within the range of the rotational angle θ b ° (1 to 3) of the backlash amount (fig. 3). However, since the lower stopper 25 rotates by itself, the rotational position of the fixed stopper body 24 provided to the lower stopper 25 changes.

If the lower stopper 25 is fixed to the guide bush 20 within the range of the rotation angle θ b [ ° ] of the backlash amount, the valve shaft holder 30 is lowered while being rotated by the screw feed mechanism 28, and when the movable stopper 34 of the valve shaft holder 30 is brought into contact with the fixed stopper 24 of the lower stopper 25, the lowermost position of the valve shaft holder 30 is raised in accordance with the rotation amount of the lower stopper 25. For example, when the pitch of the internal thread 26 of the lower stopper 25 (the distance between the threads) is p, the amount of rise Hb of the lowermost position of the valve shaft holder 30 at the time of backlash cancellation is defined by p × θ b/360 ((3) of fig. 3).

After the backlash is cancelled (after the rotation angle of the lower stopper 25 reaches the rotation angle θ b [ ° ] of the backlash amount) (in this state, the lower surface side of the female screw portion 26 of the lower stopper 25 contacts the upper surface side of the fixed screw portion 23 of the guide bush 20), when the lower stopper 25 is further rotated in the valve opening direction, the lower stopper 25 starts to rotate and rise, and a gap h is formed between the lower stopper 25 and the stopper 27a of the guide bush 20.

Finally, when the lower stopper 25 is fixed to the guide bush 20 by rotating by the rotation angle θ in the valve opening direction from the state of abutting and tightening against the stopper portion 27a of the guide bush 20, the lowest position of the valve shaft holder 30 is raised by the raising amount H defined by p × θ b/360, and therefore, when the valve shaft holder 30 is located at the lowest position, a gap having a dimension H in the raising and lowering direction is formed between the valve body 14 and the valve seat portion 46 a. On the other hand, a gap H defined by subtracting the amount of backlash from the above-described amount of increase H, that is, a gap defined by p × (θ - θ b)/360, is formed between the lower stopper 25 and the stopper portion 27a of the guide bush 20.

In the illustrated embodiment, the lower stopper 25 is rotated beyond the rotation angle θ b [ ° ] of the backlash amount to form the gap h between the lower stopper 25 and the stopper 27a of the guide bush 20, but when the dimension in the lifting direction of the gap formed between the valve body 14 and the valve seat portion 46a is set to be equal to or less than Hb, the lower stopper 25 may be rotated within the range of the rotation angle θ b [ ° ] of the backlash, so that no gap is formed between the lower stopper 25 and the stopper 27a of the guide bush 20, and the state in which (the lower surface of) the lower stopper 25 abuts against the stopper 27a of the guide bush 20 is maintained.

In the above-described embodiment, the state in which the lower stopper 25 is brought into contact with and tightened against the stopper portion 27a of the guide bush 20 is set as the reference state of the rotation of the lower stopper 25 in the valve opening direction (i.e., the seated state), but it is needless to say that the tightened state and the position in the vertical direction of the lower stopper 25 in the reference state are not limited to the illustrated embodiment. For example, the lower stopper 25 may be set to an arbitrary state within the range of the rotation angle of the backlash amount shown in (1) to (3) of fig. 3 as the reference state. The lower stopper 25 does not need to be in contact with the stopper portion 27a of the guide bush 20 in the reference state, and may be in a reference state at an arbitrary position of (the fixed screw portion 23 of) the guide bush 20, for example, as shown in fig. 3 (4). In addition, when the reference state is a state in which the lower stopper 25 is separated from (not in contact with) the stopper portion 27a of the guide bush 20, the backlash does not exist, and after the completion of assembly (i.e., the separated state), a dimension H in the vertical direction of a gap formed between the valve body 14 and the valve seat portion 46a is smaller than a gap H between (a lower surface of) the lower stopper 25 and the stopper portion 27a of the guide bush 20 (in other words, a gap H in the vertical direction of the lower stopper 25 and the stopper portion 27a of the guide bush 20 is larger than the dimension H).

In addition, in the illustrated embodiment, the downward movement of the lower stopper 25 is restricted by the stopper portion 27a constituted by the upper surface of the fitting portion 27 of the guide bush 20, but for example, as shown in fig. 4, the downward movement of the lower stopper 25 may be restricted by forming the incomplete thread portion 23a in (the lower end of) the fixed thread portion 23 formed on the outer periphery of the cylindrical portion 21 of the guide bush 20 to restrict the tightening of the female thread portion 26 of the lower stopper 25.

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 therewith. At this time, the valve shaft 10 is moved up and down along with the valve element 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, whereby the clearance (lift amount) between the valve element 14 and the valve seat portion 46a is increased or decreased, and the flow rate of the fluid such as the refrigerant is adjusted. Even when the movable stopper 34 of the valve shaft holder 30 abuts against the fixed stopper 24 fixed to the guide bush 20 and the valve element 14 is located at the lowermost position, a predetermined amount of flow rate can be secured because a gap (a required lift amount when the valve is closed) is formed between the valve element 14 and the valve seat portion 46a (see fig. 5).

As described above, in the motor-operated valve 1 according to embodiment 1, each portion is designed so as to be able to obtain a seated state and a separated state, the seated state being: a lower stopper 25 having a female screw portion 26 with a screw pitch p is relatively rotatably screwed to a predetermined position of the guide bush 20, and when the valve shaft holder 30 is positioned at the lowermost movement position by the lower stopper mechanism 29, the valve body 14 abuts against the valve seat portion 46 a; the separation state is: when the lower stopper 25 located at the predetermined position is connected to the guide bush 20 so as to be relatively non-rotatable by rotating the lower stopper 25 in the valve opening direction by a predetermined rotation angle θ with respect to the guide bush 20, a gap having a dimension H in the vertical direction defined by p × θ/360 is formed between the valve body 14 and the valve seat portion 46a when the valve shaft holder 30 is located at the lowermost movement position by the lower stopper mechanism 29; the lower stopper 25 is connected to the guide bush 20 so as not to be relatively rotatable after being rotated in the valve opening direction with respect to the guide bush 20, thereby defining the lowermost position of the valve body 14, in other words, the gap between the valve body 14 and the valve seat portion 46a when the valve body 14 is located at the lowermost position. That is, since the dimensional accuracy of the gap between the valve body 14 and the valve seat portion 46a at the origin position is substantially determined by the dimensional accuracy of the female screw portion 26 of the lower stopper 25 constituting the lower stopper mechanism 29 and the fixed screw portion 23 of the guide bush 20, it is possible to suppress dimensional variations of the gap and to improve the controllability of the flow rate of the fluid (refrigerant) in the low flow rate region.

In addition, the rotor pressing member 72 is formed integrally with the positioning portion 73, so that the number of components can be prevented from increasing.

[ 2 nd embodiment ]

Fig. 6 is a longitudinal sectional view showing a motor-operated valve 2 according to the present invention.

In the motor-operated valve 1 according to embodiment 1 described above, the lower stopper 25 provided with the fixed stopper body 24 is directly joined to (the fixed screw portion 23 of) the guide bush 20 and is fixedly connected thereto, but in the motor-operated valve 2 according to embodiment 2, the lower stopper 25 is connected so as not to be rotatable with respect to (the fixed screw portion 23 of) the guide bush 20 via a stopper pressing piece (pressing member) 35 that is engaged with the lower stopper 25 and prevents relative rotation of the lower stopper 25 with respect to (the guide bush 20), and the other configuration is substantially the same as that of the motor-operated valve 1 according to embodiment 1 described above. Therefore, only the structure of the stopper presser 35 will be described in detail below, and the same structure as that of the motor-operated valve 1 shown in fig. 1 and the like will be denoted by the same reference numerals, and detailed description thereof will be omitted. The operation of the motor-operated valve 2 according to embodiment 2 is also the same as that of the motor-operated valve 1 according to embodiment 1.

As can be best understood by referring to fig. 7, the stopper presser (pressing member) 35 of the motor-operated valve 2 of the present embodiment is formed of a disc-shaped member in which the insertion hole 35a of the lower stopper 25 is formed, and a pair of support claws 36a and 36b are erected on substantially opposite sides (positions substantially separated by 180 °) of the outer peripheral portion of the insertion hole 35a with respect to the axis O so as to sandwich the lower stopper 25. The pair of support claws 36a, 36b are provided so as to face the outer surface of the lower stopper 25, and the relatively small (relatively small in width and height in the circumferential direction) support claw 36b of the pair of support claws 36a, 36b is disposed adjacent to the sector portion 35b of the fitting hole 35a through which the fixed stopper body 24 having a sector shape in a plan view is inserted (specifically, adjacent to the side surface on the valve opening direction side of the fixed stopper body 24 fitted in the sector portion 35 b). Further, a support claw 36C is erected at an outer peripheral portion of the sector portion 35b (specifically, a portion adjacent to a side surface on the opposite side to the side surface on the valve opening direction side of the fixed stopper body 24 fitted to the sector portion 35 b) so as to face an outer surface of the fixed stopper body 24, and the support claw 36C holds both side surfaces together with the support claw 36b in the circumferential direction of the fixed stopper body 24.

The lower stopper 25 is screwed (with the female screw portion 26 of) the guide bush 20 in a relatively rotatable state, the stopper holder 35 is externally attached to the lower stopper 25, and when the lower stopper 25 sandwiched by the supporting claws 36a, 36b, and 36C is rotated in the valve opening direction (counterclockwise in the drawing in plan view) about the axis O together with the stopper holder 35, the lower stopper 25 is rotated while being lifted (in some cases, only rotated without being lifted). In this state, when the lower stopper 25 is joined and fixed to the flange portion 47 of the valve main body 40 by welding, adhesion, or the like, the lower stopper 25 is coupled so as not to be rotatable relative to (the fixed screw portion 23 of) the guide bush 20 (see fig. 6).

The support claws 36a, 36b, and 36c can be formed by, for example, bending a part of the stopper holder 35 substantially vertically.

To briefly describe the assembly process of the motor-operated valve 2, particularly the process of extending the origin position (the lowermost position) of the valve element 14, a seated state is first formed through the same process as in embodiment 1. Next, from this seated state, the assembly in which the valve shaft 10, the valve shaft holder 30, the rotor 51, the retaining locking member 70, and the like are integrated is lifted up while being rotated by the screw feeding mechanism 28 and removed from the guide bush 20, and then the stopper presser 35 is mounted on the valve body 4 with the lower stopper 25 being externally attached (see fig. 8 a), and the lower stopper 25 is rotated by a predetermined rotation angle in the valve opening direction together with the stopper presser 35 with respect to the guide bush 20 (see fig. 8B). Then, the stopper holder 35 is joined and fixed to the flange-like plate 47 of the valve main body 40 by welding, adhesion, or the like, the lower stopper 25 is relatively non-rotatably coupled to (the fixed screw portion 23 of) the guide bush 20, and then the assembly is assembled to the guide bush 20 again by the screw feed mechanism 28. Accordingly, since the position of the fixed stopper body 24 of the lower stopper 25 with respect to the guide bush 20 changes, even when the movable stopper body 34 of the valve shaft holder 30 abuts against the fixed stopper body 24 of the lower stopper 25 and the valve shaft holder 30 is located at the lowermost position, a gap (a gap having a dimension H in the vertical direction) of a predetermined size is formed between the valve body 14 and the valve seat portion 46a, and the separated state is formed as in the above-described embodiment 1.

In the first stage of assembling the valve shaft 10, the guide bush 20, the lower stopper 25, the compression coil spring 60, the valve shaft holder 30, the rotor 51, the valve body 40, and the like, the stopper holder 35 may be assembled by being externally fitted to the lower stopper 25. The stopper holder 35 may be fixed to the guide bush 20 fixed to the valve body 40 instead of or together with the flange-like portion 47 of the valve body 40.

As described above with reference to fig. 4 in embodiment 1, in the present embodiment, it is needless to say that, instead of the stopper portion 27a formed by the upper surface of the fitting portion 27 of the guide bush 20, the incomplete thread portion 23a may be formed on (the lower end of) the fixed thread portion 23 formed on the outer periphery of the cylindrical portion 21 of the guide bush 20, so that tightening of the female thread portion 26 of the lower stopper 25 is restricted, and downward movement of the lower stopper 25 is restricted.

As described above, in the motor-operated valve 2 according to embodiment 2, the lower stopper 25 can be finely positioned with respect to the guide bush 20 by the stopper presser (pressing member) 35 that prevents the relative rotation of the lower stopper 25 with respect to the guide bush 20, and therefore, the dimensional variation of the gap can be effectively suppressed.