JP6721237B2 - Motorized valve - Google Patents

Description

The present invention relates to a motor-operated valve that is used as a flow control valve or the like incorporated in a refrigeration cycle of an air conditioner, a refrigerator, etc., and in particular, a valve body is at a lowest position (normally in a fully closed state). At times, the present invention relates to a valveless type electric valve in which a gap of a predetermined size is formed between the valve seat portion and the valveless valve.

As this type of electrically operated valve, for example, a valve shaft, a guide stem having a cylindrical portion into which the valve shaft is inserted, and a cylindrical shape that is retained and fixed to the lower end portion of the valve shaft and inserted into the guide stem. A valve holder and a coil spring that is inserted into the valve holder so as to be relatively movable and relatively rotatable in the axial direction with respect to the valve shaft, and is attached downward by a coil spring that is compressed between the valve holder and the valve shaft. A valve body that is energized and that is retained and locked by the valve holder, a valve body that has a valve seat portion that contacts and separates the valve body, and that has the guide stem attached and fixed to the valve body; A can, a rotor disposed on the inner circumference of the can, a rotor holder that connects the rotor and the valve shaft via a coupling member that is externally fitted and fixed to the upper end of the valve shaft, and the rotor. A concave portion formed in the rotor holder so that the engaging portion provided in the can fits therein, a stator arranged on the outer periphery of the can for rotating the rotor, and a stator arranged on the inner periphery of the cylindrical portion of the guide stem. A screw for connecting and disconnecting the valve element to and from the valve seat portion, which comprises a female screw member, a fixed screw portion formed on the inner circumference of the female screw member, and a movable screw portion formed on the outer circumference of the valve shaft. The guide mechanism includes a feed mechanism and a stopper mechanism that is disposed on the outer periphery of the cylindrical portion of the guide stem to regulate the vertical movement of the rotor. The stopper mechanism has an upper locking portion and a lower locking portion. A spiral fixed stopper, a first abutment portion that abuts and is engaged with the upper engagement portion, and a second abutment portion that abuts and is engaged with the lower engagement portion are provided. And a slider having a ring shape or a spiral shape incorporated in a spiral portion of the fixed stopper, the slider being configured such that when the rotor rotates, the first contact portion is moved by a pushing portion provided on the rotor. When pushed, the first abutment portion is moved up and down while rotating until the first abutment portion abuts on the upper engagement portion and the second abutment portion abuts on the lower engagement portion. At the origin position where the second contact portion of the slider is brought into contact with the lower locking portion and stopped, a gap of a predetermined size is formed between the valve body and the valve seat portion. The thing is known (for example, refer patent document 1).

In the motor-operated valve having the above-described configuration, even when the valve body is at the lowest position (normally in the fully closed state), a gap of a predetermined size is formed between the valve body and the valve seat portion. Compared with a normal closed-type electric valve, it is possible to reliably prevent the valve body from biting into the valve seat part, and when using the electric valve in an air conditioner, there is an advantage that it is possible to prevent operational failure due to seizure of the compressor. ..

Japanese Patent No. 5164579

By the way, in the conventional valve-less type motor-operated valve as described above, the first conduit for refrigerant inflow and outflow is provided at one side of the valve chamber of the valve body, and the second conduit for refrigerant inflow and outflow is provided at the lower part of the valve chamber. Are connected and fixed by brazing or the like, respectively, and the fluid (refrigerant) flows from the first conduit to the second conduit through the valve chamber in one direction (forward direction) and from the second conduit through the valve chamber to the first conduit. It is designed to be flowed in both directions to the other direction (reverse direction) toward the side, but backlash (screw play) is inevitable in the screw feed mechanism (between the fixed screw part and the movable screw part that make up the screw feed mechanism). Therefore, when the flow direction of the fluid (refrigerant) changes from the forward direction to the reverse direction or from the reverse direction to the forward direction, the valve body is biased by the pressure of the fluid and the valve body moves toward the valve seat portion. On the other hand, the backlash (screw backlash) moves up and down (see FIGS. 9A and 9B).

Further, in the above conventional motor-operated valve, the valve body that controls the flow rate of the fluid flowing through the valve orifice is usually formed by an inverted truncated cone surface or an inverted conical surface (tapered surface). Therefore, when the valve element moves up and down with respect to the valve seat portion in accordance with the change in the flow direction of the fluid as described above, the valve element is at the origin position (also called the lowest position, and the number of pulses supplied to the motor is 0). There is a problem that the flow rate (also referred to as 0 pulse flow rate) of the fluid flowing through the valve orifice changes before and after the change in the flow direction of the fluid when in the pulse position (see FIG. 10). ).

The present invention has been made in view of the above problems, and an object thereof is to suppress a change in flow rate due to a change in the flow direction of a fluid (refrigerant) when the valve body is at the lowest position. It is to provide an electric valve that can be operated.

In order to solve the problems described above, the motor-operated valve according to the present invention is provided with a valve shaft provided with a valve body and a valve orifice having a valve seat portion in which the valve body is brought into contact with or separated from or close to each other, A valve main body in which a valve chamber through which a fluid is introduced and discharged is formed, a motor having a rotor connected to the valve shaft and a stator for rotating the rotor, and a fixing screw portion provided on the valve main body side. A screw feed mechanism for moving the valve element of the valve shaft with respect to the valve seat portion of the valve body in response to rotational driving of the rotor. A lower stopper mechanism for restricting the downward rotation of the valve shaft, and between the valve body and the valve seat portion when the valve body is at the lowest position by the lower stopper mechanism. A motor-operated valve in which a gap is formed and fluid is allowed to flow in both a positive direction from the valve chamber to the valve orifice and a reverse direction from the valve orifice to the valve chamber. At least when the valve body is at the lowest position, the upper surface of the movable screw portion of the screw feed mechanism is brought into contact with the lower surface of the fixed screw portion or the screw feed regardless of the flow direction of the fluid. the lower surface of the movable threaded portion of the mechanism in order to contact with the upper surface of the fixing screw portion, urging member for preventing the backlash which biases the lifting direction is provided to the movable threaded part relative to the fixing screw portion, the The backlash preventing biasing member acts in a low flow rate range in which the biasing force of the valve body with respect to the valve seat portion is equal to or less than a predetermined valve opening degree, and the biasing force is from a low flow rate range to a large flow rate. It is characterized in that it is set so that it does not act after reaching the inflection point of the flow rate at the intermediate opening of the valve opening of the valve element after switching to the region.

In a more specific aspect, a valve shaft provided with a valve body, a valve shaft holder connected and fixed to the valve shaft, and the valve shaft is inserted such that the valve shaft is relatively movable and relatively rotatable in the axial direction. A valve provided with a guide bush and a valve opening orifice having a valve seat portion where the valve body comes into contact with or separates from or closely separates from each other, forms a valve chamber through which fluid is introduced and led out, and the guide bush is attached and fixed. A main body, a motor having a rotor connected to the valve shaft holder and a stator for rotating the rotor to rotate the valve shaft holder with respect to the guide bush, and a fixing screw formed on the guide bush. And a movable screw portion formed on the valve shaft holder, and screw feed for moving up and down the valve body of the valve shaft with respect to the valve seat portion of the valve body in accordance with rotational driving of the rotor. A mechanism, a fixed stopper body provided on a lower stopper having a female screw portion screwed to the fixing screw portion of the guide bush, and a valve stopper provided on the valve shaft holder in order to regulate the downward movement of the valve shaft holder. And a lower stopper mechanism including a movable stopper body, and a gap is formed between the valve body and the valve seat portion by the lower stopper mechanism when the valve body is at the lowest position. At the same time, the motor-operated valve is configured to allow fluid to flow in both a positive direction from the valve chamber toward the valve orifice and a reverse direction from the valve orifice toward the valve chamber, and at least the valve. When the body is at the lowest position, the upper surface of the movable screw portion of the screw feed mechanism is brought into contact with the lower surface of the fixed screw portion regardless of the flow direction of the fluid, or the movable screw of the screw feed mechanism is used. A backlash-preventing biasing member for biasing the valve shaft holder in the up-and-down direction with respect to the guide bush so as to bring the lower surface of the portion into contact with the upper surface of the fixing screw portion is provided , and the backlash-preventing biasing member is provided. After the urging force acts in a low flow rate range in which the valve opening of the valve element with respect to the valve seat portion is equal to or less than a predetermined valve opening degree, and the urging force is switched from the low flow rate range to the large flow rate range. It is characterized in that it is set so as not to operate after reaching the inflection point of the flow rate at the intermediate opening degree of the valve opening degree of the valve body .

The backlash preventing biasing member is preferably interposed between the valve body and the valve shaft.

The backlash preventing biasing member is preferably interposed between the guide bush and the valve shaft.

The backlash preventing biasing member is preferably interposed between the lower stopper and the valve shaft holder.

Preferably, a can in which the rotor is rotatably inserted and the stator is externally fitted is connected and fixed to the valve body, and the backlash preventing biasing member includes the can and the valve shaft holder. Intervened between.

According to the present invention, at least when the valve element is at the lowest position, the upper surface of the movable screw portion of the screw feed mechanism is brought into contact with the lower surface of the fixed screw portion regardless of the fluid flow direction, or in the screw feed mechanism. A biasing member that biases the movable screw portion in the up-and-down direction with respect to the fixed screw portion so that the lower surface of the movable screw portion abuts the upper surface of the fixed screw portion. There is provided a backlash preventing biasing member that biases the valve shaft holder to a guide bush mounted and fixed to the valve main body in a vertical direction. Therefore, there is no backlash (screw backlash) of the screw feed mechanism (between the fixed screw part and the movable screw part forming the screw feed mechanism), and even if the flow direction of the fluid (refrigerant) changes, the valve body will not contact the valve seat part. When the valve body is at the lowest position, the flow rate change due to the change in the flow direction of the fluid (refrigerant) can be reliably suppressed.

Further, since the backlash preventing biasing member is set so that the biasing force acts at least in a low flow rate range in which the valve opening degree of the valve body with respect to the valve seat portion is equal to or less than a predetermined valve opening degree. The flow rate change due to the change of the flow direction of the fluid (refrigerant) in the low flow rate range that requires precise flow rate adjustment can be reliably avoided, and the torque (rotation torque) is increased by the biasing force of the backlash prevention biasing member. Can be restricted.

1 is a vertical sectional view showing a first embodiment of a motor-operated valve according to the present invention. FIG. 2 is an enlarged vertical cross-sectional view of a main part of the motor-operated valve shown in FIG. 1 in an enlarged manner. The figure which shows the flow volume characteristic of the motor operated valve shown by FIG. The longitudinal cross-sectional view which shows 2nd Embodiment of the motor operated valve which concerns on this invention. The longitudinal cross-sectional view which shows 3rd Embodiment of the motor operated valve which concerns on this invention. The longitudinal cross-sectional view which shows 4th Embodiment of the motor operated valve which concerns on this invention. The longitudinal cross-sectional view which shows 5th Embodiment of the motor-operated valve which concerns on this invention. FIG. 8 is a vertical cross-sectional view showing a modified form of the electric valve shown in FIG. 7. It is a principal part expansion longitudinal cross-sectional view which expands and shows the principal part of the conventional motor operated valve, (A) is a figure which shows a forward flow state, (B) is a figure which shows a reverse flow state. The figure which shows the flow volume characteristic of the conventional motor operated valve.

Hereinafter, embodiments of a motor-operated valve according to the present invention will be described with reference to the drawings. In each drawing, the gaps formed between the members and the distances between the members may be exaggerated for easier understanding of the invention and for convenience of drawing. is there. Further, in the present specification, the description indicating the position and direction such as up and down and left and right is based on the direction arrow display in FIG. 1 and the like, and does not indicate the position and direction in the actual use state.

Further, in the present specification, from the first conduit connected to the side of the valve chamber in the valve body to the lower side of the valve chamber via the valve chamber and the vertically oriented valve orifice formed at the bottom of the valve chamber. The direction toward the connected second conduit is referred to as the “forward direction”, and the direction from the second conduit through the valve orifice and the valve chamber toward the first conduit is referred to as the “reverse direction”.

[First Embodiment]
<Structure and operation of electric valve>
FIG. 1 is a vertical sectional view showing a first embodiment of a motor-operated valve according to the present invention.

The electrically 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 can 55, a stepping motor 50 including a rotor 51 and a stator 52, A compression coil spring (biasing member for urging the valve closing direction) 60, a retaining locking member 70, a screw feed mechanism 28, and a lower stopper mechanism 29 are provided.

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 orifice 46 at the lower end of the lower small-diameter portion 13. The stepped inverted frustoconical valve body 14 for controlling the passage flow rate of 1) is integrally formed.

As can be seen from FIG. 1 and FIG. 2, the valve body 14 includes an upper tapered surface portion 14t formed of an inverted truncated cone surface that is long in the central axis O direction (vertical direction) from the upper side (valve chamber 40a side), The upper taper surface portion 14t has a lower taper surface portion 14u formed of an inverted truncated cone surface having a control angle (an angle of intersection with a line parallel to the central axis O of the valve body 14) larger than that of the upper taper surface portion 14t.

The guide bush 20 is composed of a cylindrical body that is inserted in a state where (the intermediate large diameter portion 12 of) the valve shaft 10 is relatively movable (sliding) in the axis O direction and is relatively rotatable around the axis O, The upper portion thereof extends to the side of the upper small diameter portion 11 of the valve shaft 10. A screw feed mechanism 28 for raising and lowering the valve body 14 of the valve shaft 10 with respect to the valve seat portion 46a of the valve body 40 in accordance with the rotational drive of the rotor 51 is provided on the outer periphery of the guide bush 20 (upper and lower central portions thereof). A fixing screw portion (male screw portion) 23 forming one side is formed. The lower portion of the guide bush 20 (the portion below the fixing screw portion 23) has a large diameter and serves as a fitting portion 27 into the fitting hole 44 of the valve body 40. A lower stopper 25 is fixed to (on the lower side of the valve shaft holder 30 in) the fixing screw portion 23 by being screwed and fixed to the upper surface 27a of the fitting portion 27 with a slight gap. A fixed stopper body 24, which constitutes one of the lower stopper mechanisms 29 for restricting the downward rotation of the valve shaft holder 30 (that is, the valve shaft 10 connected to the valve shaft holder 30), is integrally provided on the outer periphery of Has been done. The upper surface 27a of the fitting portion 27 serves as a stopper portion that regulates the lower movement of the lower stopper 25 (in other words, defines the lower movement limit position or the lowermost movement position of the lower stopper 25).

Note that, here, the lower stopper 25 is fixed to the fixing screw portion 23 of the guide bush 20 with a slight gap from the upper surface 27a of the fitting portion 27, but the valve body 14 is at the lowest position (origin position). If a gap of a predetermined size is formed between the valve body 14 and the valve seat portion 46a when the guide bush is in the state of, the lower stopper 25 is brought into contact with the upper surface 27a of the fitting portion 27 to guide the guide bush. It may be fixed to the fixing screw portion 23 of 20.

The valve shaft holder 30 includes a cylindrical portion 31 into which the guide bush 20 is inserted, and a ceiling portion 32 having an insertion hole 32a through which an upper end portion of (the upper small diameter portion 11 of) the valve shaft 10 is inserted. Have A movable screw portion (female screw portion) that is screwed with the fixing screw portion 23 of the guide bush 20 to form the screw feed mechanism 28 on the inner periphery of the cylindrical portion 31 (lower half portion) of the valve shaft holder 30. 33 is formed, and at the lower end of the outer periphery of the cylindrical portion 31, a movable stopper body 34 that constitutes the other of the lower stopper mechanisms 29 is integrally provided.

Further, the valve shaft is provided between the (upward) terrace surface formed between the upper small diameter portion 11 and the intermediate large diameter portion 12 of the valve shaft 10 and the lower surface of the ceiling portion 32 of the valve shaft holder 30. 10, the valve shaft 10 and the valve shaft holder 30 are urged in a direction in which the valve shaft 10 and the valve shaft holder 30 separate in the up-and-down direction (axis O direction), in other words, the valve shaft 10 (the valve body 14 A compression coil spring (a biasing member for biasing in the valve closing direction) 60 that constantly biases (1)) downward (in the valve closing direction) is compressed.

The valve body 40 is composed of a metal cylindrical body 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 by brazing or the like to a lateral first opening 41 provided at a side portion of the valve chamber 40a. An insertion hole through which the valve shaft 10 (the intermediate large-diameter portion 12 thereof) is relatively movable (sliding) in the direction of the axis O and is relatively rotatable around the axis O in the ceiling portion of the valve chamber 40a. 43 and a lower portion (fitting portion 27) of the guide bush 20 are fitted to each other to form a fitting hole 44. The fitting hole 44 is formed in the lower portion of the valve chamber 40a. The two conduits 42a are connected and fixed by brazing or the like. In addition, a substantially frustoconical valve opening orifice 46 having a valve seat portion 46a for contacting or separating the valve body 14 with or away from the bottom wall 45 provided between the valve chamber 40a and the second opening 42. The valve seat portion 46a is provided with a straight portion 46s having a cylindrical surface (having a constant inner diameter in the ascending/descending direction) (see FIG. 2).

The straight portion 46s (inside diameter thereof) is designed to be slightly smaller in diameter than the lower small diameter portion 13 of the valve shaft 10.

An annular flat surface 45f is formed around the valve orifice 46 (valve seat portion 46a) on the upper surface of the bottom wall 45 of the valve body 40, and the annular flat surface 45f and the lower small diameter portion of the valve shaft 10 are formed. 13 and the intermediate large diameter portion 12 between the (downward) terrace surface, that is, around the lower small diameter portion 13 of the valve shaft 10 in the valve chamber 40a, the valve shaft 10 and the valve body 40. A compression coil spring (backlash preventing urging member) 61 for urging and urging the valve shaft 10 away from each other in the ascending/descending direction (axis O direction), in other words, urging the valve shaft 10 upward is compressed. The biasing force (compressing force) of the compression coil spring (backlash preventing biasing member) 61 is set so as not to interfere with the position (for example, the origin position) of the valve element 14 relative to the valve seat portion 46a determined by the screw feed mechanism 28. It is set smaller than the urging force (compressing force) of the compression coil spring (biasing member for urging the valve closing direction) 60.

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

A rotor 51 is rotatably arranged (interpolated) inside the can 55 and outside the guide bush 20 and the valve shaft holder 30, and the rotor 51 is rotatably driven outside the can 55. , A yoke 52a, a bobbin 52b, a stator coil 52c, a resin mold cover 52d, and the like are arranged (exterior). A plurality of lead terminals 52e are connected to the stator coil 52c, and a plurality of lead wires 52g are connected to the lead terminals 52e via a substrate 52f. The existing rotor 51 is adapted to rotate around the axis O.

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

Specifically, the rotor 51 has a double pipe structure 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 angular position around the axis O, Vertical grooves 51d extending in the direction of the axis O (vertical direction) (for example, at an angular interval of 120 degrees around the axis O) are formed on the inner circumference of the inner cylinder 51a.

On the other hand, on the outer periphery (upper half portion) of the valve shaft holder 30, a protrusion 30a extending vertically (for example, at an angular interval of 120 degrees around the axis O) is provided in a protruding manner, and a lower portion of the protrusion 30a is provided. Upward locking surfaces (not shown) that support the rotor 51 are formed on both sides.

By engaging the vertical groove 51d of the inner cylinder 51a of the rotor 51 with the protrusion 30a of the valve shaft holder 30 and contacting the lower surface of the inner cylinder 51a of the rotor 51 with the locking surface of the valve shaft holder 30, 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.

Above the rotor 51 and the valve shaft holder 30, the valve shaft holder 30 and the rotor 51 are prevented from moving relative to each other in the vertical direction (in other words, the rotor 51 is pressed downward against the valve shaft holder 30) and the valve In order to connect the shaft 10 and the valve shaft holder 30, a push nut 71 fitted and fixed to the upper end of the valve shaft 10 (the upper small diameter portion 11 thereof) by press fitting, welding or the like, the push nut 71 and the rotor 51. And a retainer locking member 70 formed of a rotor retainer 72 formed of a disc-shaped member having a through hole 72a formed at the center thereof, which is interposed between the rotor retainer 72 and the upper end portion of the valve shaft 10. ing. That is, the rotor 51 is sandwiched between the valve shaft holder 30 and the rotor retainer 72, which are biased upward by the biasing force of the compression coil spring 60. The height (vertical direction) from the upper end of the valve shaft holder 30 to the locking surface is almost the same as the (vertical direction) height of the inner cylinder 51a of the rotor 51, and the height of the valve shaft holder 30 The upper surface of 32) is in contact with the lower surface (flat surface) of the rotor retainer 72.

In addition, the push nut 71 fixed to the upper end of the valve shaft 10 moves the valve shaft holder 30 excessively upward with respect to the guide bush 20 during operation, so that the fixing screw portion 23 of the guide bush 20 and the valve are not moved. In order to prevent the shaft holder 30 from being unscrewed from the movable screw portion 33, a return spring (returning member) 75 formed of a coil spring for urging the valve shaft holder 30 toward the guide bush 20 is provided. When the valve body 14 is near the lowest position (origin position), in other words, in the low flow rate region where the valve opening is small (the valve opening is equal to or less than the predetermined valve opening), the return spring 75 is used for the valve. The shaft holder 30 is not biased toward the guide bush 20 (that is, the valve shaft holder 30 is not biased).

In the motor-operated valve 1, the valve body 14 is at the lowest position (origin position) in order to prevent the valve body 14 from biting the valve seat portion 46a and ensure controllability in a low flow rate range. At a certain time, a gap of a predetermined size is formed between (the upper tapered surface portion 14t of the valve body 14) and the valve seat portion 46a.

In the motor-operated valve 1 having such a configuration, when the rotor 51 is rotated by energization of (the stator coil 52c of) the stator 52, the valve shaft holder 30 and the valve shaft 10 are rotated integrally with the rotor 51. At this time, the valve feed shaft 28 is moved up and down together with the valve disc 14 by the screw feed mechanism 28 including the fixing screw portion 23 of the guide bush 20 and the movable screw portion 33 of the valve shaft holder 30. The clearance (lift amount, valve opening) between the valve seat portion 46a and the valve seat portion 46a is increased or decreased to adjust the flow rate of the fluid such as the refrigerant. Further, even 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 come into contact with each other and the valve body 14 is at the lowermost position, the valve body 14 and the valve seat are not in contact with each other. Since a gap (required lift amount at the time of valve closing) is formed between the portion 46a and the portion 46a, a predetermined amount of passing flow rate is secured (see FIG. 3).

Here, in the screw feed mechanism 28 for moving the valve body 14 up and down with respect to the valve seat portion 46 a, the movable screw portion 33 of the valve shaft holder 30 to which the valve body 14 (valve shaft 10) is connected, and the valve body 40. Although there is backlash (screw looseness) between the connecting bush and the fixing screw portion 23 of the guide bush 20, in the motor-operated valve 1 of the present embodiment, the annular flat surface 45f of the valve body 40 and the lower portion of the valve shaft 10 are arranged. The compression coil spring 61 is compressed around the lower small-diameter portion 13 of the valve shaft 10 in the valve chamber 40a between the terrace surface formed between the small-diameter portion 13 and the intermediate large-diameter portion 12. Therefore, the valve shaft holder 30 connected and fixed to the valve shaft 10 is biased upward with respect to the guide bush 20 connected and fixed to the valve body 40, and the upper surface side of the movable screw portion 33 of the valve shaft holder 30 is guided by the guide bush 20. Is abutted (pressed) on the lower surface side of the fixing screw portion 23 (see FIG. 2).

In the motor-operated valve 1 of the present embodiment, the fluid (refrigerant) is bidirectional, specifically, from the first conduit 41a (first opening 41) through the valve chamber 40a and the valve orifice 46 to the second conduit 42a ( The direction toward the second opening 42) (that is, the lateral→downward direction) (hereinafter, this state is referred to as a forward flow state), and the valve port orifice 46 and the valve chamber 40a from the second conduit 42a (the second opening 42). Through the first conduit 41a (first opening 41) (that is, downward → lateral direction) (hereinafter, this state is referred to as a reverse flow state). In the forward flow state, the valve element 14 is urged downward by the pressure of 1. and in the reverse flow state, the valve element 14 is urged upward, but in the forward flow state and the reverse flow state. In both states, as described above, the upper surface side of the movable screw portion 33 of the valve shaft holder 30 is brought into contact with the lower surface side of the fixing screw portion 23 of the guide bush 20 by (the biasing force of) the compression coil spring 61. Yes (pressed). Therefore, there is no backlash (screw rattling) between the fixed screw portion 23 and the movable screw portion 33 forming the screw feed mechanism 28, and the flow direction of the fluid (refrigerant) is from the normal direction to the reverse direction or from the reverse direction to the normal direction. Even if the valve body 14 changes in the direction, the valve body 14 does not move up and down with respect to the valve seat portion 46a. Therefore, as shown in FIG. 3, the flow of the fluid (refrigerant) when the valve body 14 is at the lowest position. The flow rate change due to the change in direction can be reliably suppressed.

By constantly biasing the valve shaft 10 upward with respect to the valve body 40 by the compression coil spring 61, as shown by the solid line in FIG. 3, the forward flow state and the reverse flow state are the same. Flow characteristics can be realized. However, during the low flow rate range where the valve opening is small, the compression coil spring 61 biases the valve shaft 10 upward with respect to the valve body 40 (the biasing force of the compression coil spring 61 acts on the valve shaft 10). The urging force of the compression coil spring 61 may not act on the valve shaft 10 after switching from the low flow rate region to the high flow rate region (after reaching the inflection point of the flow rate at the intermediate opening degree). .. That is, after the natural length of the compression coil spring 61 exceeds the inflection point of the flow rate at the intermediate opening degree, the annular flat surface 45f of the valve body 40, the lower small diameter portion 13 of the valve shaft 10 and the intermediate large diameter portion 12 are connected. It may be designed to be shorter than the distance between the terrace surface formed between the two. In this case, as shown by the dotted line in FIG. 3, in the large flow rate region where the valve opening degree is large after exceeding the inflection point of the flow rate at the intermediate opening degree, the flow rate in the forward flow state and the reverse flow state is increased. The characteristics will change (by backlash (thread backlash)), but in the low flow rate range where the valve opening is small before exceeding the inflection point of the flow rate at the intermediate opening, the forward flow state and the reverse flow state The flow rate characteristics are the same in both regions of the state and the distance (valve opening) at which the biasing force of the compression coil spring 61 acts on the valve shaft 10 can be limited. Therefore, it is possible to surely avoid the flow rate change due to the change in the flow direction of the fluid (refrigerant) in the low flow rate region that requires precise flow rate adjustment (in other words, the controllability of the fluid flow rate in the low flow rate region can be secured). An increase in torque (rotational torque) due to the biasing force of the compression coil spring 61 can be limited.

<How to assemble the motorized valve>
An example of an assembling process of the above-described motor-operated valve 1, particularly an example of an origin position (lowermost position) setting process of the valve body 14 will be outlined with reference to FIG. 1. First, the valve shaft 10, the guide bush 20, and the lower part The stopper 25, the compression coil spring 60, the valve shaft holder 30, the rotor 51, the compression coil spring 61, the valve body 40, etc. are assembled. At this time, the lower stopper 25 is screwed into the guide bush 20 so as to be rotatable relative to the guide bush 20. The lower stopper 25 may be disposed in contact with the stopper portion 27a of the guide bush 20 at this stage, or may be disposed apart from the stopper portion 27a. Then, (the upper tapered surface portion 14t of) the valve element 14 provided at the lower end portion of the valve shaft 10 abuts the valve seat portion 46a, the compression coil spring 60 and the compression coil spring 61 are slightly compressed, and the valve shaft holder 30 Until the movable stopper 34 and the fixed stopper 24 of the lower stopper 25 come into contact with each other, and (the lower surface of) the lower stopper 25 comes into contact with the stopper portion 27a of the guide bush 20, the fixed screw portion 23 of the guide bush 20 and the valve are formed. Using the screw feed mechanism 28 including the movable screw portion 33 of the shaft holder 30, the valve shaft holder 30, the rotor 51, and the valve shaft 10 are rotated and lowered. Then, with the valve shaft holder 30 being positioned at the lowermost moving position and the valve body 14 being lowered from the lowermost position in this manner, the rotor retainer 72 is fitted onto the upper end portion of the valve shaft 10. At the same time, the push nut 71 is externally fitted and fixed by press fitting, welding or the like.

Next, from the above state, an assembly in which the valve shaft 10, the valve shaft holder 30, the rotor 51, the retaining member 70 (the push nut 71 and the rotor retainer 72) and the like are integrated is attached to the screw feed mechanism 28. After being utilized, the lower stopper 25 is rotated and raised to be removed from the guide bush 20, and then the lower stopper 25 is rotated with respect to the guide bush 20 in a valve opening direction (counterclockwise in plan view) by a predetermined rotation angle. At this time, the lower stopper 25 may be rotated until it rises from the stopper portion 27a of the guide bush 20, or may be rotated while being in contact with the stopper portion 27a (for the amount of backlash). Then, the lower stopper 25 is connected and fixed to (the fixing screw portion 23 of) the guide bush 20 by welding, welding, bonding or the like so as not to be relatively rotatable, and then the screw feeding mechanism 28 is used again to reassemble the assembly into the guide bush. Assemble to 20. As a result, the position of the fixed stopper 24 of the lower stopper 25 with respect to the guide bush 20 changes, so that the movable stopper 34 of the valve shaft holder 30 and the fixed stopper 24 of the lower stopper 25 contact each other, and the valve shaft holder 30 is removed. Even when the valve body 14 is at the lowermost position (that is, the valve body 14 is at the lowest position), a gap of a predetermined size between the valve body 14 and the valve seat portion 46a (the ascending/descending direction in the forward flow state) A gap having a dimension of H) is formed. At this time, as described above, the upper surface side of the movable screw portion 33 of the valve shaft holder 30 is brought into contact with the lower surface side of the fixing screw portion 23 of the guide bush 20 by (the biasing force of) the compression coil spring 61. .. After the assembly is lifted and removed from the guide bush 20, the lower stopper 25 is rotated with respect to the guide bush 20 by a predetermined rotation angle in the valve opening direction, and the lower stopper 25 is welded/welded to the guide bush 20. The description has been made assuming that they are connected and fixed to each other so as not to rotate relative to each other by adhesion or the like. As long as the gap can be rotated and the lower stopper 25 can be connected and fixed to the guide bush 20 by welding, welding, bonding or the like so as not to rotate relative to each other, the assembly can be removed from the guide bush 20. No need to remove.

[Second Embodiment]
FIG. 4 is a vertical cross-sectional view showing a second embodiment of the motor-operated valve according to the present invention.

The motor-operated valve 2 of the second embodiment is different from the motor-operated valve 1 of the first embodiment in the arrangement configuration of the compression coil spring (bias member for preventing backlash) 61, and other configurations are the same as those described above. It is almost the same as the motor-operated valve 1 of the first embodiment. Therefore, the portions corresponding to the respective portions of the motor-operated valve 1 of the first embodiment described above will be denoted by the same reference numerals and detailed description thereof will be omitted, and in the following, only the differences will be described in detail.

In the motor-operated valve 2 of the second embodiment, the lower small diameter portion 13 of the valve shaft 10 is formed in a stepped manner, and the upper portion of the lower small diameter portion 13 extends to the inside of the guide bush 20 and the valve main body 40 In the insertion hole 43 provided in the ceiling of the valve chamber 40a, the lower small-diameter portion 13 (the upper large-diameter portion thereof) of the valve shaft 10 is relatively movable (sliding) in the axis O direction and is relatively rotatable around the axis O. It is inserted in a rotatable state.

Then, the (downward) terrace formed between the bottom surface of the fitting hole 44 of the valve body 40 (the portion around the insertion hole 43) and the lower small diameter portion 13 and the intermediate large diameter portion 12 of the valve shaft 10. Between the surface, that is, around the lower small diameter portion 13 of the valve shaft 10 inside the guide bush 20, the valve shaft 10 and the valve body 40 are urged in a direction to move away from each other in the vertical direction (axis O direction), In other words, a compression coil spring (backlash preventing biasing member) 61 that biases the valve shaft 10 upward is compressed. Also here, the biasing force (compressing force) of this compression coil spring (backlash preventing biasing member) 61 is set so as not to obstruct the determination of the position (for example, the origin position) of the valve element 14 relative to the valve seat portion 46a by the screw feed mechanism 28. Is set to be smaller than the biasing force (compressing force) of the compression coil spring (valve closing biasing member) 60.

Also in the motor-operated valve 2 of the present embodiment, in both the forward flow state and the reverse flow state, the upper surface side of the movable screw portion 33 of the valve shaft holder 30 is guided by the compression coil spring 61 (urging force thereof). Since the lower surface side of the fixing screw portion 23 of 20 is abutted (pressed), the same operational effect as the electrically operated valve 1 of the first embodiment can be obtained.

Further, in the motor-operated valve 2 of the present embodiment, the compression coil spring 61 is arranged inside the guide bush 20 in the fitting hole 44 of the valve body 40 (in place of the valve chamber 40a), so that the valve chamber The effect that the flow of the fluid (refrigerant) in 40a is not obstructed, and the characteristic change (elastic force change) of the compression coil spring 61 due to the flow of the fluid (refrigerant) in the valve chamber 40a can be avoided.

[Third Embodiment]
FIG. 5 is a vertical cross-sectional view showing a third embodiment of the electrically operated valve according to the present invention.

The motor-operated valve 3 of the third embodiment is different from the motor-operated valve 2 of the second embodiment in the arrangement configuration of the compression coil spring (biasing member for preventing backlash) 61, and other configurations are the same as those described above. It is almost the same as the motor-operated valve 2 of the second embodiment. Therefore, the portions corresponding to the respective portions of the motor-operated valve 2 of the second embodiment described above are denoted by the same reference numerals, and detailed description thereof will be omitted. Below, only the differences will be described in detail.

In the motor-operated valve 3 according to the third embodiment, the lower end portion of (the fitting portion 27 of) the guide bush 20 fitted into the fitting hole 44 of the valve body 40 has the brim-shaped portion 27b protruding inward. It is provided. In the present example, the hole diameter of the hole formed by the collar-shaped portion 27b is substantially the same as the hole diameter of the insertion hole 43 provided in the ceiling portion of the valve chamber 40a of the valve body 40. The lower small-diameter portion 13 (the upper large-diameter portion thereof) of the valve shaft 10 is inserted into 27b in a state capable of relative movement (sliding) in the direction of the axis O and relative rotation around the axis O.

Then, between the upper surface of the collar-shaped portion 27b of the guide bush 20 and the (downward) terrace surface formed between the lower small diameter portion 13 and the intermediate large diameter portion 12 of the valve shaft 10, that is, the above-mentioned first As in the second embodiment, the valve shaft 10 and the valve body 40 are biased inside the guide bush 20 around the lower small-diameter portion 13 of the valve shaft 10 in the upward and downward directions (axis O direction). For example, a compression coil spring (backlash preventing biasing member) 61 that biases the valve shaft 10 upward is compressed.

Therefore, it is needless to say that the motor-operated valve 3 of the present embodiment can also obtain the same operational effects as the motor-operated valve 2 of the second embodiment.

[Fourth Embodiment]
FIG. 6 is a vertical sectional view showing a fourth embodiment of the motor-operated valve according to the present invention.

The motor-operated valve 4 of the fourth embodiment is different from the motor-operated valve 1 of the first embodiment in the arrangement configuration of the compression coil spring (bias member for preventing backlash) 61, and other configurations are the same as those described above. It is almost the same as the motor-operated valve 1 of the first embodiment. Therefore, the portions corresponding to the respective portions of the motor-operated valve 1 of the first embodiment described above will be denoted by the same reference numerals and detailed description thereof will be omitted, and in the following, only the differences will be described in detail.

In the motor-operated valve 4 of the fourth embodiment, an annular mounting groove 25a is provided in (the outer periphery of) the lower stopper 25 that is screwed and fixed to the fixing screw portion 23 of the guide bush 20, and the mounting groove 25a ( Between the (upward) bottom surface and the lower surface of (the cylindrical portion 31 of) the valve shaft holder 30, the valve shaft holder 30 and the lower stopper 25 connected and fixed to the guide bush 20 are vertically moved (axis O direction). A compression coil spring (backlash preventing biasing member) 61 that biases the valve shaft holder 30 upward, which biases the valve shaft holder 30 upward, is compacted.

In this example, the intermediate large-diameter portion 12 of the valve shaft 10 extends into the valve chamber 40a of the valve body 40 through the insertion hole 43 provided in the ceiling of the valve chamber 40a of the valve body 40.

Also in the motor-operated valve 4 of the present embodiment, the upper surface side of the movable screw portion 33 of the valve shaft holder 30 is guided by the compression coil spring 61 (biasing force) in both the forward flow state and the reverse flow state. Since the lower surface side of the fixing screw portion 23 of 20 is abutted (pressed), the same operational effect as the electrically operated valve 1 of the first embodiment can be obtained.

Further, in the motor-operated valve 4 of the present embodiment, since the compression coil spring 61 (the biasing force thereof) directly acts on the valve shaft holder 30 having the movable screw portion 33, the flow rate accompanying the change of the flow direction of the fluid (refrigerant). The effect that the change can be suppressed more reliably is obtained.

[Fifth Embodiment]
FIG. 7 is a vertical sectional view showing a fifth embodiment of the motor-operated valve according to the present invention.

The motor-operated valve 5 of the fifth embodiment is different from the motor-operated valve 1 of the first embodiment in the arrangement configuration of the compression coil spring (backlash preventing biasing member) 61 and the return spring 75, and the other components. The configuration is almost the same as that of the motor-operated valve 1 of the first embodiment. Therefore, the portions corresponding to the respective portions of the motor-operated valve 1 of the first embodiment described above will be denoted by the same reference numerals and detailed description thereof will be omitted, and in the following, only the differences will be described in detail.

In the motor-operated valve 5 according to the fifth embodiment, the upper end of the return spring 75 that is mounted on the push nut 71 extends to the ceiling of the can 55, and the rotor retainer 72 and the can 55 that are disposed on the valve shaft holder 30 are disposed. The return spring 75 is interposed between and in a compressed state. That is, in the present embodiment, the return spring 75 is compressed between the can 55 and the valve shaft holder 30 (via the rotor retainer 72), and the valve shaft holder 30 is connected to the valve body 40. It functions as a compression coil spring (backlash preventing biasing member) 61 that biases the fixed can 55 in the up-down direction (axis O direction), in other words, biases the valve shaft holder 30 downward. Will be done). That is, in the present embodiment, the return spring 75 (the compression coil spring 61 as the backlash prevention biasing member) has a valve opening degree that is close to the lowest position (origin position) of the valve body 14. Even in a small flow rate range where the valve opening is small (the valve opening is less than or equal to a predetermined valve opening), the valve shaft holder 30 is biased toward the guide bush 20 (that is, the valve shaft holder 30 is biased). ing.

Note that, also in the present example, as in the fourth embodiment, the intermediate large diameter portion 12 of the valve shaft 10 passes through the insertion hole 43 provided in the ceiling portion of the valve chamber 40a of the valve body 40, and the valve chamber 40a of the valve body 40a. It has been extended to the inside.

In the motor-operated valve 5 of the present embodiment, contrary to the motor-operated valves 1 to 4 of the above-described first to fourth embodiments, in both the forward flow state and the reverse flow state, the compression coil spring 61 (= The lower surface of the movable screw portion 33 of the valve shaft holder 30 is abutted (pressed) against the upper surface of the fixing screw portion 23 of the guide bush 20 by (the biasing force of the return spring 75). As a matter of course, the same operational effects as those of the motor-operated valve 1 of the first embodiment can be obtained.

In addition, in the motor-operated valve 5 of the present embodiment, a return spring 75 as a return member that prevents the fixed screw portion 23 and the movable screw portion 33 of the screw feed mechanism 28 from being unthreaded and a backlash preventing biasing member. Since it can also be used as the compression coil spring 61, the effect of reducing the number of parts can be obtained.

In addition, in the said 1st-5th embodiment, in order to absorb the impact at the time of determining the position (origin position) of the valve body 14 with respect to the valve seat part 46a, the upper small diameter part 11 and the intermediate large diameter part 12 of the valve shaft 10 are eased. Although a compression coil spring (a biasing member for biasing the valve closing direction) 60 is compressed between the (upward) terrace surface formed between and the lower surface of the ceiling portion 32 of the valve shaft holder 30, As shown in FIG. 8 (FIG. 8 shows an electrically operated valve 5A as a modification of the electrically operated valve 5 of the fifth embodiment), if the valve body 14 can be positioned with respect to the valve seat portion 46a, this compression The coil spring 60 may be omitted.

1 Motorized valve (first embodiment)
2 Motorized valve (second embodiment)
3 Motorized valve (third embodiment)
4 Motorized valve (fourth embodiment)
5 Motorized valve (fifth embodiment)
5A motor-operated valve (a modification of the fifth embodiment)
10 valve shaft 14 valve body 20 guide bush 23 fixing screw part (male screw part)
24 Fixed Stopper 25 Lower Stopper 25a Mounting Groove (Fourth Embodiment)
27 Fitting portion 27b Collar-shaped portion (third embodiment)
28 Screw feeding mechanism 29 Lower stopper mechanism 30 Valve shaft holder 33 Movable screw part (female screw part)
34 movable stopper body 40 valve body 40a valve chamber 41 first opening 41a first conduit 42 second opening 42a second conduit 45 bottom wall 45f annular flat surface 46 valve orifice orifice 46a valve seat portion 46s straight portion 47 collar portion 50 stepping Motor 51 Rotor 52 Stator 55 Can 60 Compression coil spring (biasing member for biasing valve closing direction)
61 Compression coil spring (biasing member for backlash prevention)
70 retainer locking member 71 push nut 72 rotor retainer 75 return spring (return member)
O axis

Claims (13)

A valve shaft provided with a valve body, a valve body having a valve opening orifice having a valve seat portion for contacting or separating the valve body with each other, and a valve body having a valve chamber through which fluid is introduced and extracted; A rotor having a rotor connected to the valve shaft and a stator for rotating the rotor; a fixed screw portion provided on the valve body side; and a movable screw portion provided on the valve shaft side. A screw feed mechanism for moving the valve body of the valve shaft up and down with respect to the valve seat portion of the valve body in accordance with the rotational drive of the valve shaft, and a lower stopper mechanism for restricting the downward movement of the valve shaft. ,,
When the valve body is at the lowest position by the lower stopper mechanism, a gap is formed between the valve body and the valve seat portion, and the fluid flows in the forward direction from the valve chamber toward the valve orifice. And a motor-operated valve adapted to flow in both directions from the valve orifice to the opposite direction toward the valve chamber,
At least when the valve body is at the lowest position, regardless of the flow direction of the fluid, the upper surface of the movable screw portion of the screw feed mechanism is brought into contact with the lower surface of the fixed screw portion or the screw feed mechanism. In order to bring the lower surface of the movable screw portion into contact with the upper surface of the fixed screw portion, a backlash preventing biasing member that biases the movable screw portion in the up-down direction with respect to the fixed screw portion is provided .
The backlash prevention biasing member acts in a low flow rate range in which the biasing force of the valve body with respect to the valve seat portion is equal to or less than a predetermined valve opening degree, and the biasing force is large from the low flow rate range. A motor-operated valve, which is set so as not to operate after reaching the inflection point of the flow rate at the intermediate opening degree of the valve opening degree of the valve body after switching to the flow rate range . A valve shaft provided with a valve body,
A valve shaft holder connected and fixed to the valve shaft,
A guide bush in which the valve shaft is inserted in a state of being relatively movable and relatively rotatable in the axial direction,
A valve body having a valve port orifice having a valve seat portion in which the valve element is brought into contact with or separated from, or closely spaced from, a valve chamber through which a fluid is introduced and formed is formed, and the guide bush is fixedly attached.
A motor having a rotor connected to the valve shaft holder and a stator for rotating the rotor in order to rotate the valve shaft holder with respect to the guide bush;
A fixed screw portion formed on the guide bush and a movable screw portion formed on the valve shaft holder, and the valve body of the valve shaft is connected to the valve seat portion of the valve body in accordance with rotational driving of the rotor. With a screw feed mechanism to raise and lower with respect to
A fixed stopper body provided on a lower stopper having a female screw portion screwed to the fixed screw portion of the guide bush and a movable stopper provided on the valve shaft holder in order to regulate the downward movement of the valve shaft holder. A lower stopper mechanism including a stopper body,
When the valve body is at the lowest position by the lower stopper mechanism, a gap is formed between the valve body and the valve seat portion, and the fluid flows in the forward direction from the valve chamber toward the valve orifice. And a motor-operated valve adapted to flow in both directions from the valve orifice to the opposite direction toward the valve chamber,
At least when the valve body is at the lowest position, regardless of the flow direction of the fluid, the upper surface of the movable screw portion of the screw feed mechanism is brought into contact with the lower surface of the fixed screw portion or the screw feed mechanism. A backlash preventing biasing member that biases the valve shaft holder in the up-down direction with respect to the guide bush is provided in order to bring the lower surface of the movable screw portion into contact with the upper surface of the fixed screw portion .
The backlash prevention biasing member acts in a low flow rate range in which the biasing force of the valve body with respect to the valve seat portion is equal to or less than a predetermined valve opening degree, and the biasing force is large from the low flow rate range. A motor-operated valve, which is set so as not to operate after reaching the inflection point of the flow rate at the intermediate opening degree of the valve opening degree of the valve body after switching to the flow rate range . The motor-operated valve according to claim 2, wherein the backlash preventing biasing member is interposed between the valve body and the valve shaft. The motor-operated valve according to claim 3, wherein the backlash preventing biasing member is arranged around the valve shaft in the valve chamber. The motor-operated valve according to claim 3, wherein the backlash preventing biasing member is disposed inside the guide bush. The electrically operated valve according to claim 2, wherein the backlash preventing biasing member is interposed between the guide bush and the valve shaft. Between the valve shaft and the valve shaft holder, a valve closing direction urging member for urging the valve body of the valve shaft in the valve closing direction is interposed.
7. The motor-operated valve according to claim 3, wherein the biasing force of the backlash preventing biasing member is smaller than the biasing force of the valve closing direction biasing member. .. The electric valve according to claim 2, wherein the backlash preventing biasing member is interposed between the lower stopper and the valve shaft holder. The motor-operated valve according to claim 8, wherein the backlash preventing biasing member is disposed in an annular mounting groove provided in the lower stopper. A valve closing direction urging member for urging the valve body of the valve shaft in the valve closing direction is interposed between the valve shaft and the valve shaft holder. The electric valve according to item 9. A can in which the rotor is rotatably inserted and the stator is externally fitted is connected and fixed to the valve body,
The motor-operated valve according to claim 2, wherein the backlash preventing biasing member is interposed between the can and the valve shaft holder. The backlash preventing biasing member biases the valve shaft holder toward the guide bush in order to prevent the fixed screw portion and the movable screw portion of the screw feed mechanism from being disengaged from each other. The motorized valve according to claim 11, wherein the motorized valve is adapted to be used as. A valve closing direction urging member for urging the valve body of the valve shaft in the valve closing direction is interposed between the valve shaft and the valve shaft holder. The electric valve according to 11 or 12.

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