JP2003329158A - Motor-driven valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To open and close a valve with low power without large driving force required for valve opening and closing even if an outer diameter of a valve holder is large. <P>SOLUTION: A rotor shaft 41 and a valve holder 18 are connected so that they are relatively rotatable, the rotor shaft 41 relatively rotate around the valve holder 18, even when frictional resistance of the valve holder 18 and a guide hole 20 is large, the rotor 43 rotates to generate thrust to move the valve holder 18 and a valve body 16 in the valve opening/closing direction. The valve body 16 is attached to the valve holder 18 in a shiftable manner in the radial direction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electric valve,
In particular, the present invention relates to a stepping motor drive type electric valve used as an electric expansion valve or the like for a refrigeration system.

[0002]

2. Description of the Related Art A stepping motor drive type electric valve used as a variable throttle valve, a flow control valve or the like has a male screw portion of a rotor shaft of a stepping motor screwed into a female screw hole of a female screw member fixed to a valve housing. Then, the rotor shaft is displaced in the axial direction by the screw engagement, and the valve element is opened and closed by the axial displacement of the rotor shaft.

In the electrically operated valve as described above, in order to obtain the sealing pressure when the valve is closed and prevent the valve body from biting into the valve seat portion, Japanese Utility Model Publication No. 3-11491 and Japanese Unexamined Patent Publication No. 6-1.
74129, JP-A-8-219317, JP-A-9-170664, and JP-A-10-22061.
No. 6, etc., a valve holder is provided with a valve body displaceable in the axial direction, and a spring provided in the valve holder biases the valve body toward the valve seat side. It has been known.

[0004]

In the conventional electric valve having a built-in buffer spring, the valve holder is directly connected to the rotor shaft of the stepping motor, and the valve holder rotates coaxially with the rotor shaft. With a structure in which the valve holder is guided and held by being fitted in the provided guide hole, the valve holder rotates and moves in the axial direction with respect to the guide hole when the valve is opened and closed. The frictional resistance between them increases, which requires a large amount of driving force required to open and close the valve, and it becomes necessary to increase the output torque of the stepping motor.

If the mounting concentricity of the spring provided in the valve holder is poor, an eccentric load acts on the friction engagement portion, increasing rotational friction, which also drives the valve required for opening and closing. Since a large amount of force is required, it becomes necessary to increase the output torque of the stepping motor.

Further, the larger the outer diameter of the valve holder, the better the guide holding accuracy of the valve holder due to the guide hole fitted therein. However, the larger the outer diameter of the valve holder, the better the distance between the valve holder and the guide hole. The frictional resistance becomes large, and the driving force necessary for opening and closing the valve is further increased, so that it becomes necessary to increase the output torque of the stepping motor.

When a male screw portion and a female screw portion are formed on the outer diameter portion of the valve holder and the valve housing, the male screw diameter becomes large because it is determined by the outer diameter of the valve holder. It becomes necessary to increase the output torque.

When the electric valve is used as an electric expansion valve for a refrigeration system, etc., the refrigerant used is a refrigerant circuit by using an alternative refrigerant such as hydrofluorocarbon (HFC) or CO _2. The increase in pressure causes a big problem in the situation where the required driving force for opening and closing the valve increases.

The present invention has been made to solve the above-mentioned problems, and the driving force required for opening and closing the valve does not increase even if the outer diameter of the valve holder is increased.
The mounting concentricity of the spring provided in the valve holder is improved, and the refrigerant used is hydrofluorocarbon (HFC) or CO ₂
Even if the required driving force for opening and closing the valve increases due to the higher refrigerant circuit pressure due to the use of alternative refrigerants such as, the opening and closing of the valve can be favorably performed with low power, and at the same time the operating noise should be reduced. The purpose is to provide an electric valve capable of

[0010]

In order to achieve the above object, an electric valve according to the present invention has a male screw portion formed on a rotor shaft of a stepping motor, which is screwed into a female screw hole of a female screw member fixed to a valve housing. An electrically operated valve that is engaged and displaces the rotor shaft in the axial direction by the screw engagement, and opens and closes the valve body with respect to the valve seat portion by the axial displacement of the rotor shaft, is provided on the valve housing side. A valve holder fitted in the guide hole and slidably supported in the axial direction from the valve housing, and the valve body is attached to the valve holder so as to be displaceable in the radial direction. A rotor shaft is rotatably connected to the rotor shaft.

According to the motor-operated valve of the present invention, since the rotor shaft and the valve holder are rotatably connected to each other, even if the frictional resistance between the valve holder and the guide hole is large, the rotor shaft does not function as a valve. It can rotate relative to the holder, and thrust is obtained by this.The valve holder carries the valve element and displaces the guide hole in the axial direction when the valve is opened and closed. The driving force (torque) required for opening and closing the valve is reduced as compared with the case of performing. Further, since the valve body can be displaced in the radial direction with respect to the valve holder, a high degree of concentricity with respect to the relative arrangement position of the valve holder and the valve seat portion is not required.

In the electrically operated valve according to the present invention, the valve holder and the rotor shaft have thrust surfaces facing each other, and between the thrust surfaces, a metal washer having a highly slippery surface and a washer made of a highly slippery resin are provided. Alternatively, a low friction resistance thrust bearing is sandwiched by a washer or the like having a highly slippery resin coating. As a result, the frictional resistance in the rotational direction between the rotor shaft and the valve holder can be sufficiently reduced by the thrust bearing.

Further, as a detailed configuration of the motor-operated valve according to the present invention, the valve holder has a cylindrical shape and supports the valve element at one end thereof so as to be displaceable in the radial direction, and the thrust at the other end. It has an end plate part that forms a surface, a through hole is formed through the center part of the end plate part, and the tip end part of the rotor shaft penetrates through the through hole in a loosely fitted state and is located in the valve holder. A flange portion forming the thrust surface is provided at the tip end portion of the rotor shaft, and the thrust bearing is arranged between the end plate portion and the flange portion, and the tip end of the rotor shaft in the valve holder A compression coil spring is mounted between the portion and the back surface of the valve body.

Also, in the motor-operated valve according to the present invention, one winding end of the compression coil spring and the tip end portion of the rotor shaft or / and the other winding end of the compression coil spring and the back surface portion of the valve body are formed. A spring bearing member is sandwiched therebetween, the compression coil spring engages with the spring bearing member in a radially constrained state, and the spring bearing member is uneven on the tip end portion of the rotor shaft or the back surface portion of the valve body. It is engaged and guided to the center of the valve holder.

According to the electrically operated valve of the present invention, the spring receiving member guides the arrangement position of the compression coil spring in the valve holder to the center, thereby improving the mounting concentricity of the compression coil spring.

Further, in the motor-operated valve according to the present invention, a spring bearing member is sandwiched between one winding end of the compression coil spring and a tip end portion of the rotor shaft or a rear surface portion of the valve body, and The coil spring is engaged with the spring receiving member in a radially restrained state, and the spring receiving member is engaged with the tip end portion of the rotor shaft or the back surface portion of the valve body in a concavo-convex manner to be guided to the center of the valve holder, The other end of the compression coil spring is provided with a projecting line portion bent in the axial direction at the spring axial center position, and the projecting line portion faces the back surface portion of the valve body or the rotor shaft facing the projecting line portion. Engages with a central small hole formed at the tip of the.

According to the motor-operated valve of the present invention, the spring receiving member guides the arrangement position of the compression coil spring in the valve holder to the center, and the protruding line portion of the compression coil spring is located on the back surface of the valve body or the rotor shaft. The center of the mating side can be pushed by engaging with the central small hole at the tip end of the, and the mounting concentricity of the compression coil spring is improved.

Further, in the motor-operated valve according to the present invention, a spring bearing member is sandwiched between one winding end of the compression coil spring and a tip end portion of the rotor shaft or a rear surface portion of the valve body, and The coil spring is engaged with the spring receiving member in a radially restrained state, and the spring receiving member is engaged with the tip end portion of the rotor shaft or the back surface portion of the valve body in a concavo-convex manner to be guided to the center of the valve holder, The other winding end of the compression coil spring is in the shape of a pick tail end and is in contact with the rear surface of the valve body or the center of the tip of the rotor shaft facing the pick tail end.

According to the motor-operated valve of the present invention, the spring receiving member guides the arrangement position of the compression coil spring in the valve holder to the center, and the compression coil spring has the picked-end end-shaped winding end so that the compression coil spring has the rear surface of the valve body. The center of the other side can be pushed by abutting against the end portion of the rotor shaft or the rotor shaft, and the mounting concentricity of the compression coil spring is improved.

Further, it is preferable that the abutting portion of the winding end having the pick tail end shape of the compression coil spring has a conical convex shape that engages with the winding end having the pick tail end shape.

Further, in the motor-operated valve according to the present invention, the compression coil spring is a conical coil spring, and a spring bearing is provided between the winding end on the large diameter side and the tip end portion of the rotor shaft or the back surface portion of the valve body. A member is sandwiched, the compression coil spring engages with the spring receiving member in a radially restrained state, and the spring receiving member engages with the tip end portion of the rotor shaft or the back surface portion of the valve body in a concavo-convex manner. The winding end on the small diameter side of the compression coil spring is guided to the center of the valve holder and abuts on the rear surface of the valve body or the center of the tip of the rotor shaft facing the winding end.

According to the motor-operated valve of the present invention, the spring receiving member guides the arrangement position of the compression coil spring by the conical coil spring in the valve holder, and
The center of the other side can be pushed by bringing the compression coil spring into contact with the back surface of the valve body or the tip of the rotor shaft with the winding end on the small diameter side, and the mounting concentricity of the compression coil spring is improved.

Further, a hemispherical convex portion is formed on the rear surface of the valve body or the tip of the rotor shaft, which is opposed to the winding end on the small diameter side of the conical coil spring, and the winding end on the small diameter side of the compression coil spring is formed. Preferably engages the hemispherical convex portion.

Further, in the motor-operated valve according to the present invention, in order to prevent the compression coil spring from buckling and tilting, the spring bearing member guides the inner diameter portion of the compression coil spring, or the compression coil. It has an extension cylindrical portion that guides the outer diameter portion of the spring.

Further, a shaft center hole is formed in the extension shaft-shaped portion of the spring receiving member, and a guide shaft-shaped portion extendedly formed on the spring receiving side facing the spring receiving member is axially formed in the shaft center hole. It is slidably fitted to.

Further, in the motor-operated valve according to the present invention, the engagement of the spring bearing member and the tip end portion of the rotor shaft or the back surface portion of the valve body with the concave and convex portions is a shallow dish shape in order to obtain a good center guiding action. It is possible to select any one of the planar engagement due to the unevenness, the spherical engagement due to the substantially hemispherical unevenness, and the pivotal engagement due to the substantially conical unevenness.

Further, in the motor-operated valve according to the present invention, between the contact position of the spring receiving member provided on the valve body side with the valve body and the seating position of the valve body with the valve seat member when the valve is closed. The distance is preferably smaller than the diameter of the valve port in this seated position.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows one embodiment of a motor-operated valve according to the present invention.

The motor-operated valve has a valve housing (main body) 10. The valve housing 10 defines a valve chamber 11 therein. In the valve housing 10, a first pipe joint 12 made of copper, which directly communicates with the valve chamber 11, and a valve seat member 14 made of stainless steel or sintered metal, which defines a valve port 13, and which is arranged at a center (center position), A second pipe joint 15 made of copper, which communicates with the valve chamber 11 via the valve port 13, is fixedly mounted by welding, brazing, or the like.

In this embodiment, the first pipe joint 1
2 will be the primary side and the second pipe joint 15 will be described as an example where the refrigerant flows so as to be the secondary side. However, in the motor-operated valve of this embodiment, the second pipe joint 15 is It is a bidirectional type that can be used even when the refrigerant flows such that it becomes the primary side and the first pipe joint 12 becomes the secondary side.

The valve housing 10 is provided with a holding cylinder 2 by a mount member 19 made of a press-formed stainless steel plate.
0 is fixedly mounted at the center of the valve chamber 11. The holding cylinder 20 has a guide hole 20A, and the cylindrical valve holder 18 is supported in the guide hole 20A so as to be slidable in the axial direction at the center position of the valve chamber 11.

A stop ring 24 is attached to one end (lower end) of the valve holder 18, and an inner diameter portion 2 of the stop ring 24 is attached.
The valve element 16 penetrates through 4A by loose fitting. As a result, the valve body 16 is held by the valve holder 18 such that it can be displaced in the radial direction by the amount of loose fitting with respect to the inner diameter portion 24 </ b> A, can be rotationally displaced, and is movable in the axial direction. By moving (up and down), the needle valve portion 17 opens and closes the valve port 13 and quantitatively increases and decreases the effective opening area.

Since the valve body 16 is displaceable in the radial direction with respect to the valve holder 18, the arrangement position of the valve holder 18 and the valve seat member 14 determined by the mounting accuracy of the holding cylinder 20 and the like.
With respect to the arrangement position of, the valve body 16 and the valve seat member 14 can be concentric with each other without requiring a high degree of concentric mounting accuracy when assembling them.

An end plate portion 21 is provided at the other end (upper end portion) of the valve holder 18, and a through hole 22 is formed through the center portion of the end plate portion 21. The stepping motor 4 is provided in the through hole 22.
One end (lower end) 41A of the rotor shaft 41 of No. 0 penetrates the valve holder 18 in a loosely fitted state so as to be rotatable and radially displaceable. A tip portion (lower end portion) 41A of the rotor shaft 41 is located inside the valve holder 18, and a flange portion 25 is formed on the tip portion 41A.

Since the rotor shaft 41 and the valve holder 18 are radially displaceable with respect to each other, the arrangement position of the rotor shaft 41 determined by the mounting accuracy of the female screw member 31 described later and the mounting accuracy of the valve guide member 19 and the like. With respect to the arrangement position of the valve holder 18 determined by the above, a high degree of concentric mounting accuracy is not required when these are assembled.

The end plate portion 21 and the flange portion 2 of the valve holder 18
5 is a thrust surface facing each other, and a thrust bearing 26 is provided between the thrust surfaces as a metal washer having a highly slippery surface, a washer made of a highly slippery resin such as fluororesin, or a washer made of a highly slippery resin coating. Is sandwiched between.

With this structure, the rotor shaft 41 and the valve holder 18 are rotatably connected to each other via the thrust bearing 26, and the rotor shaft 41 rotates with respect to the valve holder 18 with low friction resistance by this connection. The valve holder 18 can be lifted (moved in the valve opening direction) in a possible mode.

A compression coil spring 29 is mounted in the valve holder 18 between the flange portion 25 and the valve body 16 in a state where a predetermined preload is applied. A spring receiving member 71 is sandwiched between one winding end 29A of the compression coil spring 29 and the flange portion 25.

As shown in FIG. 2, the spring receiving member 71 has a short shaft-shaped spring stop portion 71A, and the spring stop portion 7 is provided.
The winding end 29A of the compression coil spring 29 is fitted to the outer periphery of the 1A to restrain the radial movement of the compression coil spring 29. In other words, the winding end 29 of the compression coil spring 29.
The A side is engaged with the spring receiving member 71 in a radially restrained state.

A shallow dish-shaped convex portion 71B having a trapezoidal cross section is formed in the center of the surface of the spring bearing member 71 facing the flange portion 25, and a trapezoidal shape is formed in the center of the surface portion of the flange portion 25 facing the spring bearing member 71. A shallow dish-shaped recess 25A having a cross section is formed, and the projection 71B and the recess 25A are planarly engaged with each other.

The other winding end 29B of the compression coil spring 29
Is fitted to the outer periphery of a short shaft-shaped spring stop portion 16A formed on the back surface of the valve body 16 and is restrained from moving in the radial direction.

Due to the above-mentioned mounting structure of the compression coil spring 29 using the spring receiving member 71, relative rotational friction is generated between the flange portion 25 and the spring receiving member 71 during rotation of the rotor, and the compression coil spring 29 in the valve holder 18 is rotated. The arrangement position is guided to the center to improve the mounting concentricity of the compression coil spring 29, and the flange portion 2 due to the rotation of the rotor shaft 41.
5 and the rotational friction resistance between the spring receiving member 71 is reduced. In addition, the needle valve portion 17 can evenly contact the valve seat member 14 without tilting, which allows the valve holder 18
The unbalanced load does not act on the frictional engagement portion between the guide hole 20 and the guide hole 20.

As a result, the frictional resistance at the time of opening / closing the valve does not increase, the operating performance is improved, the driving force required for opening / closing the valve is reduced as compared with the conventional one, and the stepping motor 4
The output torque of 0 can be reduced.

A female screw member 31 is fixed to the upper portion 20B of the holding cylinder 20. The female screw member 31 is made of a sintered metal containing a solid lubricant or a synthetic resin such as PPS resin filled with a filler having good lubricity such as fluororesin, and has a female screw hole 32 formed at the center thereof.

A male screw portion 33 having a diameter sufficiently smaller than the outer diameter of the valve holder 18 is integrally formed on the rotor shaft 41. The male screw portion 33 penetrates the female screw hole 32 in a threaded engagement state, and the rotor shaft 41 rotates around its own central axis line to rotate by the screw engagement between the male screw portion 33 and the female screw hole 32. Move in the axial direction.

The motor-operated valve is a hydrofluorocarbon (HF
C) or CO ₂ or the like, when used as an electric expansion valve for a refrigeration system of a high-pressure specification with a high-pressure specification, if the rotor diameter of the stepping motor 40 described later is about 15 to 20 mm, the male screw part 33 The effective diameter of the valve holder 1
Since the diameter is sufficiently smaller than the outer diameter of 8, the female screw hole 3
2. The effective diameter of the male screw portion 33 can be set to 2.5 to 6.0 mm, and the screw pitch can be set to about 0.35 to 0.60 mm.

The rotor shaft 41 is fixedly connected to the rotor 43 of the stepping motor 40. The outer peripheral portion 43A of the rotor 43 is a multi-pole permanent magnet with alternating N-pole and S-pole, which is composed of a ferrite sintered product, a rare earth sintered magnet, or a plastic magnet.

A cup-shaped rotor case 44 having a cylindrical cross section made of a press-formed stainless steel plate is hermetically fixed to the upper end surface portion 34 of the valve housing 10. The airtight fixing of the rotor case 44 is performed by abutting the annular opening edge portion 44C of the rotor case 44 against the flat upper end surface portion 34 of the valve housing 10 and butt welding the entire circumference by TIG welding, plasma welding or laser welding. Is done by. This butt weld is designated by reference numeral 3 in FIG.
It is indicated by 5.

The butt welding indicated by the butt welding portion 35 is performed up to the same thickness as the thickness of the rotor case 44, and the boundary surface between the valve housing 10 and the rotor case 44 is formed by joining the surfaces. Does not exist.

By such butt welding, the internal pressure of the rotor case 44 is reduced to the valve housing 10 and the rotor case 44.
There is no action in the direction of separating the welding surface portion of and from, and the compressive strength of the joint portion between the valve housing 10 and the rotor case 44 is improved.

The rotor case 44 accommodates the rotor 43 of the stepping motor 40 rotatably in a concentric state on the inner side, and the annular stator element 45 is fixedly arranged on the outer side.

The stator element 45 has stator coils 46 in upper and lower two stages, is entirely molded with an electrically insulating resin 47, and has a plurality of magnetic pole teeth (not shown) at equal intervals on the entire inner peripheral portion. ing.

The mounting piece 4 is attached to the stator element 45.
9 is fixed. The mount piece 49 is fixed to the stator element 45 by being positioned at a predetermined position related to the circumferential position of the magnetic pole teeth of the stator element 45, and is a hemispherical projection portion 50 as a stator positioning shape portion.
Has been press molded.

Dimples 51 are press-molded on the rotor case 44. The dimple 51 forms a positioning shape portion for the stator into which the hemispherical protrusion 50 fits in the concave portion 51A on the outer peripheral surface side of the rotor case, and the convex portion 51B on the inner peripheral surface side of the rotor case positions the guide support body to be described later. It has a shape.

In the mount piece 49, the hemispherical projection 50 is fitted in the recess 51A of the dimple 51, so that the stator element 45 is prevented from being pulled out and the mounting position of the stator element 45 in the circumferential direction with respect to the rotor case 44 is set. ing.

A guide support 52 is provided in the rotor case 44.
Is fixed. The guide support body 52 has a hanging cylindrical portion (cylindrical body) 53 and an umbrella-shaped portion 54 formed on the upper end side of the hanging cylindrical portion 53, and is integrally formed by press working as a whole. The umbrella-shaped portion 54 is formed in the same shape as the top inner side 44B of the rotor case 44, and the umbrella-shaped portion 54 has a convex portion 51 of the dimple 51 as a positioning shape portion for the guide support.
The notch engaging portion 55 that engages with B is press-molded.

In the guide support body 52, the umbrella-shaped portion 54 is alignedly engaged with the top inner side 44B of the rotor case 44, and the notch engagement portion 55 is engaged with the convex portion 51B of the dimple 51, so that the rotor case 44 is formed. It is fixed in the rotor case 44 in a state where the mounting position in the circumferential direction is set.

The hanging cylindrical portion 53 is concentric with the rotor 43 and extends downward from the center of the top of the rotor case 44 in the axial direction. A key-shaped valve-opening stopper projection 56 is axially formed over a predetermined length at a predetermined circumferential position of a base portion (a connection portion with the umbrella-shaped portion 54) of the hanging cylindrical portion 53. Further, at the tip end (lower end) of the hanging cylindrical portion 53,
A positioning hole 57 is press-molded by a louver molding die at a position having a predetermined circumferential positional relationship with the notch engaging portion 55. At the inner part of the positioning hole 57, there is a cut and raised piece (uncut piece) 58 formed by louver molding.

The hanging cylindrical portion 53 is provided with a spiral guide wire body 60 formed in a coil spring shape from a wire material having a spring property so as to surround the outer circumference of the hanging cylindrical portion 53. The spiral guide wire body 60 has a stopper wire body portion (valve closing stopper portion) 61 extended in the axial direction at the lower end portion, and an engagement formed by bending the tip end of the stopper wire body portion 61 inward in the radial direction. It integrally has an end 62.

The spiral guide wire 60 is in contact with the end face of the valve opening stopper protrusion 56 at the upper end side, the engaging end 62 is inserted and fitted in the positioning hole 57, and the tip of the engaging end 62 is the spiral guide wire. The cut-and-raised piece 58 is abutted by the radial elastic force of 60.

As a result, the spiral guide wire 60 is sandwiched between the end surface of the valve opening stopper projection 56 and the positioning hole 57 due to the axial spring load, and the mounting position in the axial direction is maintained without rattling. The stopper wire body portion 61 is positioned and locked by the depending cylindrical portion 53 at a position determined by the arrangement position of the positioning hole 57.

A movable stopper member 63 is rotatably engaged with the spiral guide wire body 60. Movable stopper member 63
Has a one-turn coil spring shape and has a stopper wire body portion 64 extending outward in the radial direction at one end. The rotor 43 has a pin-shaped protrusion 43 for kicking around the movable stopper member 63 at a predetermined circumferential position based on the magnetic pole position of the permanent magnet.
B is integrally molded.

The movable stopper member 63 contacts the pin-shaped protrusion 43B of the rotor 43 at the stopper wire body portion 64, and is kicked around by the rotation of the rotor 43 to guide the spiral guide wire body 60 while rotating. The spiral guide wire body 60 moves in the axial direction of the spiral guide wire body 60 by the spiral movement, and the stopper wire body portion 64 abuts on the stopper wire body portion 61 of the spiral guide wire body 60, whereby further left rotation is stopped, The origin position of the rotor 43 is mechanically set based on the valve closing reference. Further, when the stopper wire body portion 64 abuts on the valve opening stopper protrusion portion 56, further clockwise rotation is stopped, and the valve open (fully open) position can be mechanically determined.

The hanging cylindrical portion 53 also serves as a rotor bearing guide, and a bearing sleeve 65 is provided in the hanging cylindrical portion 53. The extension shaft portion 41B of the rotor shaft 41 is fitted into the bearing sleeve 65 so as to be rotatable and slidable in the axial direction, and the upper end side of the rotor shaft 41 is the bearing sleeve 6.
Supported by 5.

Here, the cylindrical body for supporting the bearing sleeve 65 is a cylindrical body for supporting the spiral guide wire body which supports the spiral guide wire body 60 of the stopper mechanism for mechanically setting the origin position of the rotor 43. It means that the number of parts can be reduced.

In the motor-operated valve having the above-mentioned structure, the drive pulse signal is applied to the stator element 45,
The rotor 43 rotates in accordance with the number of pulses, the rotor shaft 41 rotates accordingly, and the rotor shaft 41 rotates due to the screw engagement relationship between the male screw portion 33 of the rotor shaft 41 and the fixed female screw member 31. Move in the axial direction.

Upward movement of the rotor shaft 41 (movement in the valve opening direction)
Is transmitted to the valve holder 18 by hitting the flange portion 25 and the end plate portion 21 which sandwich the thrust bearing 26,
The valve holder 18 and the valve body 16 are moved upward by the upward movement of the rotor shaft 41.

In this upward movement, the rotor shaft 41 can slide and rotate relative to the valve holder 18 with low friction resistance by the thrust bearing 26, and the valve holder 18 can be rotated.
Even if the frictional resistance between the valve holder 18 and the guide hole 20 is large, the thrust due to the rotation of the rotor 43 is obtained and the valve element 16 moves upward only by displacing the guide hole 20 and the guide hole 20 in the axial direction. Accordingly, even if the outer diameter of the valve holder 18 is large, the driving force required for opening the valve is small, and the valve can be opened with low power.

Downward movement of the rotor shaft 41 (movement in the valve closing direction)
Is transmitted to the valve holder 18 by the contact of the flange portion 25, the thrust bearing 26, the end plate portion 21, the spring receiving member 71, and the compression coil spring 29, and the valve holder 18 and the valve body 16 move downward.

Even in this descending movement, the rotor shaft 41 can slide and rotate relative to the valve holder 18 with low friction resistance by the thrust bearing 26, and the valve holder 1
8 and the guide hole 20 have a large frictional resistance, the rotor 4
A thrust force due to the rotation of 3 is obtained, and the valve body 16 moves downward. Accordingly, even if the outer diameter of the valve holder 18 is large, the driving force required for closing the valve is small, and the valve can be closed with low power.

One end (lower end) of the rotor shaft 41 is supported by the female screw member 31 at the male screw portion 33, and the other (upper end) is supported by the bearing sleeve 65 by the extension shaft portion 41B. Rotational vibration of the rotor 43 is reduced as compared with the case where it is supported by holding. This reduces operating noise when the valve is opened and closed.

Due to the mounting structure of the compression coil spring 29 using the spring receiving member 71, relative rotational friction is generated between the flange portion 25 and the spring receiving member 71 when the rotor is rotated, and the arrangement position of the compression coil spring 29 in the valve holder 18 is increased. Is improved to improve the mounting concentricity of the compression coil spring 29, and the rotational frictional resistance between the flange portion 25 and the spring receiving member 71 due to the rotation of the rotor shaft 41 is reduced. Further, the needle valve portion 17 can evenly contact the valve seat member 14 without tilting, and thus an unbalanced load acts on the frictional engagement portion (fitting portion) between the valve holder 18 and the guide hole 20. There is no.

As a result, the frictional resistance at the time of opening / closing the valve does not increase, the operating performance is improved, the driving force required for opening / closing the valve is reduced as compared with the conventional one, and the stepping motor 4
The output torque of 0 can be reduced. Alternatively,
Compatible with high voltage.

As shown in FIG. 3, the spring receiving member 71 is replaced between the one winding end 29A of the compression coil spring 29 and the flange portion 25, and the other winding end 29B of the compression coil spring 29. It can also be sandwiched between and the back surface of the valve body 16.

In this case, the flange portion 25 is provided with a short shaft-shaped spring stopper portion 25B, and one winding end 29A of the compression coil spring 29 is engaged with the spring stopper portion 25B in a radially constrained state so as to receive the spring bearing. A shallow dish-shaped recess 16B having a trapezoidal cross section is provided in the center of the back surface of the valve body 16 facing the member 71 so that the projection 71B of the spring receiving member 71 and the recess 16B of the valve body 16 are engaged with each other in a planar manner. It is enough, when the rotor is rotating, the valve body 1
6 and the spring bearing member 71 generate relative rotational friction.

In this embodiment, the thrust faces of the flange portion 28 of the valve body 16 and the retaining ring 24 facing each other are provided with metal washers having a highly slippery surface and a highly slippery resin such as a fluororesin. Auxiliary thrust bearing 2 such as a washer or a washer coated with a highly slippery resin
7 is provided.

Further, as shown in FIG. 4, the spring bearing member 71 is one winding end 29A of the compression coil spring 29.
And the flange portion 25, and between the other winding end 29B of the compression coil spring 29 and the back surface portion of the valve element 16, and in this case, when the rotor is rotating, the flange portion 25 and Relative rotational friction occurs between the spring bearing member 71 and / or between the valve element 16 and the spring bearing member 71.

Further, as shown in FIG. 5, the spring receiving member 71 is provided with a shallow dish-shaped concave portion 71C, and a member facing this, for example, the flange portion 25 is provided with a shallow dish-shaped convex portion 25C, The concave portion 71C and the convex portion 25C may be engaged with each other.

In the embodiment shown in FIGS. 6, 7, and 8, the spring stop portion 71A of the spring bearing member 71 is extended in axial length to form an extended shaft portion 71D, and the extended shaft portion is formed. 71D
The inner diameter of the compression coil spring 29 is engaged with the outer circumference of the.

In the embodiment, the extension shaft portion 71D of the spring receiving member 71 guides the inner diameter portion of the compression coil spring 29, so that the compression coil spring 29 buckles.
Tilt is prevented, and the operating performance is further improved.

In the embodiment shown in FIG. 9, a shaft center hole 71E is formed in the extension shaft portion 71D of the spring bearing member 71, and the valve body 16 facing the spring bearing member 71 and forming the spring bearing side. A guide shaft-shaped portion 16D is integrally formed with the guide shaft-shaped portion 16D, and the guide shaft-shaped portion 16D is slidably fitted in the shaft center hole 71E.

In this embodiment, since the spring bearing member 71 moves by being guided by the fitting of the guide shaft portion 16D and the shaft center hole 71E, the straightness of the movement is improved and the compression coil spring 29 is moved. Buckling and tilting are prevented more reliably, and the operating performance is further improved.

As shown in FIG. 10, when the spring bearing side facing the spring bearing member 71 is the rotor shaft 41, the flange portion 25 is integrally formed with the guide shaft-shaped portion 25D. 25D may be slidably fitted in the shaft center hole 71E of the spring receiving member 71, and as shown in FIG. 11, when the spring receiving members 71 are arranged on both sides of the compression coil spring 29. Is provided with a shaft center hole 71E in one spring receiving member 71 and a guide shaft-shaped portion 71F in the other spring receiving member 71, and the shaft center hole 71E and the guide shaft-shaped portion 7 are provided.
It may be slidably fitted to 1F.

In the embodiment shown in FIGS. 12 and 13, a piston-like extension tubular portion 71G is fitted in the spring receiving member 71 on the inner periphery of the valve holder 18 so as to be slidable in the axial direction.
Are integrally formed, and the outer diameter portion of the compression coil spring 29 is engaged with the inner circumference of the extension tubular portion 71G.

In the embodiment, the extension cylindrical portion 71G of the spring receiving member 71 guides the outer diameter portion of the compression coil spring 29, so that the compression coil spring 29 buckles.
Tilt is prevented, and the operating performance is further improved. Also,
Since the extension tubular portion 71G is fitted in the inner circumference of the holder 18 so as to be slidable in the axial direction, the straightness of movement of the spring receiving member 71 is improved, and the compression coil spring 29 buckles. Tilt is more reliably prevented.

In the embodiment shown in FIGS. 14 and 15, the tip of the long-axis convex portion 71H of the spring receiving member 71 is formed in a substantially hemispherical shape, and the deep concave portion 16E of the valve body 16 is formed. The bottom portion is formed in a substantially hemispherical shape, and the convex portion 71H and the concave portion 16E are formed.
And are engaged with each other in a spherical joint manner.

As a result, the arrangement position of the compression coil spring 29 in the valve holder 18 is guided to the center, and the mounting concentricity of the compression coil spring 29 is improved, and the valve body 16 and the spring receiving member 71 due to the rotation of the rotor shaft 41. Rotational friction resistance with and is reduced. Further, the needle valve portion 17 can evenly contact the valve seat member 14 without tilting, and an unbalanced load does not act on the frictional engagement portion between the valve holder 18 and the guide hole 20.

As a result, the frictional resistance at the time of valve opening / closing does not increase, the operating performance is improved, the driving force required for valve opening / closing is reduced compared to the conventional one, and the output torque of the stepping motor 40 is reduced. Can be reduced.

As shown in FIG. 15, when the spring bearing members 71 are provided on both sides of the compression coil spring 29, the spherical joint type spring bearing member 71 on the valve body 16 side is The rotation stop pin 73 prevents the valve body 16 from rotating.

In the embodiment shown in FIG. 16, the tip of the convex portion 71J of the spring receiving member 71 is formed in a substantially conical shape, and the bottom portion of the concave portion 16F of the valve body 16 is formed in a substantially conical shape. The convex portion 71J and the concave portion 16F are engaged with each other in a pivot manner.

As a result, the arrangement position of the compression coil spring 29 in the valve holder 18 is guided to the center to improve the mounting concentricity of the compression coil spring 29, and the rotation of the rotor shaft 41 causes the flange portion 25 or the valve element 16 to move. The rotational friction resistance with the spring bearing member 71 is reduced. Further, the needle valve portion 17 can evenly contact the valve seat member 14 without tilting, and an unbalanced load does not act on the frictional engagement portion between the valve holder 18 and the guide hole 20. As a result, the frictional resistance at the time of opening / closing the valve does not increase, the operating performance is improved, the driving force required for opening / closing the valve is reduced, and the output torque of the stepping motor 40 is reduced as compared with the conventional one. Can be planned.

In the embodiment shown in FIG. 17, the spring receiving member 71 is sandwiched between the one winding end 29A of the compression coil spring 29 and the flange portion 25 at the tip of the rotor shaft, and the compression coil spring The winding end 29A of 29 is the spring bearing member 7
1 in a radially restrained state, and the spring receiving member 71 has a convex portion 71B and a concave portion 2 similar to those of the above-described embodiment.
The flange portion 25 is engaged with the flange portion 25 by means of 5A.

On the other winding end 29B of the compression coil spring 29, a protruding line portion 29 is bent in the axial direction at the spring axial center position.
C is bent, and the protruding line portion 29C is inserted and engaged with a central small hole 16G formed in the back surface portion of the valve body 16 facing the protruding line portion 29C.

The bottom of the central small hole 16G has a protruding line portion 29 when the compression coil spring 29 and the valve body 16 rotate relative to each other.
A steel ball 74 is provided as a thrust bearing to reduce the frictional resistance with the tip of C.

According to this embodiment, the spring receiving member 7
1, the arrangement position of the compression coil spring 29 in the valve holder 18 is guided to the center, and the projecting line portion 29C of the compression coil spring 29 is provided at the central small hole 1 on the back surface of the valve body 16.
By engaging with 6G, the other side can be pushed at the center, and the mounting concentricity (centering performance) of the compression coil spring 29 is improved.

As a result, the rotational frictional resistance between the flange portion 25 and the spring bearing member 71 due to the rotation of the rotor shaft 41 is reduced. Further, the needle valve portion 17 can evenly contact the valve seat member 14 without tilting, and an unbalanced load does not act on the frictional engagement portion between the valve holder 18 and the guide hole 20. As a result, the frictional resistance at the time of opening / closing the valve does not increase, the operating performance is improved, the driving force required for opening / closing the valve is reduced, and the output torque of the stepping motor 40 is reduced as compared with the conventional one. Can be planned.

As shown in FIG. 18, the compression coil spring 29 is arranged on the spring receiving member 71 between the lower winding end 29B of the compression coil spring 29 and the rear surface of the valve body 16.
The protruding line portion 29D may be bent and formed on the winding end 29A on the upper side of, and the protruding line portion 29D may be inserted and engaged with the central small hole 25D formed in the flange portion 25 facing the protruding line portion 29D.

In the embodiment shown in FIG. 19, the spring receiving member 71 is sandwiched between the one winding end 29A of the compression coil spring 29 and the flange portion 25 at the tip of the rotor shaft, and the compression coil spring is formed. The winding end 29A of 29 is the spring bearing member 7
1 in a radially restrained state, and the spring receiving member 71 has a convex portion 71B and a concave portion 2 similar to those of the above-described embodiment.
The flange portion 25 is engaged with the flange portion 25 by means of 5A.

The other winding end 29E of the compression coil spring 29.
Has a pick tail end shape, and is in contact with the center of the back surface of the valve body 16 facing the pick tail end.

In this embodiment, the spring receiving member 71 guides the position of the compression coil spring 29 in the valve holder 18 to the center, and the compression coil spring 29 has the winding end 29E having a pick tail end shape. 1
By abutting against the back surface of 6, the other side can be pushed in the center, and the mounting concentricity of the compression coil spring 29 is improved.

As a result, the rotational frictional resistance between the flange portion 25 and the spring bearing member 71 due to the rotation of the rotor shaft 41 is reduced. Further, the needle valve portion 17 can evenly contact the valve seat member 14 without tilting, and an unbalanced load does not act on the friction engagement portion between the valve holder 18 and the guide hole 20. The resistance does not increase, the operating performance is improved, the driving force required for opening and closing the valve is reduced, and the output torque of the stepping motor 40 can be reduced as compared with the conventional one.

As shown in FIG. 20, the compression coil spring 29 is disposed between the lower winding end 29B of the compression coil spring 29 and the rear surface of the valve body 16 on the spring receiving member 71.
The upper winding end 29F may be formed in a pick tail end shape and brought into contact with the recess 25A of the flange portion 25 at the tip of the rotor shaft.

Further, as shown in FIGS. 21 and 22, the contact portion (contact partner) of the winding end 29E or 29F having the pick tail end shape of the compression coil spring 29 has a conical convex shape 16H or 25E. , This engagement may be provided with automatic centripetal property.

In the embodiment shown in FIG. 23, the compression coil spring 29 is formed of a conical coil spring, and the spring receiving member 71 is provided between the winding end 29G on the large diameter side and the back surface of the valve body 16. The winding end 2 of the compression coil spring 29 that is sandwiched
9G engages with the spring receiving member 71 in a radially constrained state, and the spring receiving member 71 engages with the flange portion 25 by the convex portion 71B and the concave portion 25A in a concavo-convex manner as in the above-described embodiment. .

Winding end 29H on the small diameter side of compression coil spring 29
Is in contact with a recessed portion 25A in the center of the flange portion 25 at the tip of the rotor shaft that faces this.

In this embodiment, the spring receiving member 71 guides the arrangement position of the compression coil spring 29 in the valve holder 18 to the center, and also the compression coil spring 29.
Since the winding end 29G on the small diameter side of the shaft functions similarly to that of the pick tail end shape and abuts on the center portion of the flange portion 25, the other end can be pushed at the center, and the mounting concentricity of the compression coil spring 29 is reduced. Be improved.

As a result, the rotational frictional resistance between the valve element 16 and the spring receiving member 71 due to the rotation of the rotor shaft 41 is reduced. In addition, the valve seat member 1 is provided without the needle valve portion 17 tilting.
4 is evenly contacted, and an unbalanced load does not act on the frictional engagement portion between the valve holder 18 and the guide hole 20. Therefore, the frictional resistance at the time of valve opening / closing does not increase, and the operating performance improves. As compared with the conventional one, the driving force required for opening and closing the valve is reduced, and the output torque of the stepping motor 40 can be reduced.

Further, as shown in FIG. 24, a hemispherical convex portion 25E is formed on the flange portion 25 at the tip of the rotor shaft facing the winding end 29H on the small diameter side of the conical coil spring 29. The winding end 29H on the small diameter side of the coil spring 29 may be engaged with the hemispherical convex portion 25E to provide automatic centripetal property.

In the above-described embodiment, the thrust bearing 2 of low friction resistance is provided between the end plate portion 21 and the flange portion 25 of the valve holder 18 and between the valve body 16 and the stop ring 24.
6 and 27 are sandwiched, but when the rotational frictional resistance between the end plate portion 21 and the flange portion 25 of the valve holder 18 is low or the rotational frictional resistance between the valve body 16 and the stop ring 24 is low, FIG.
As shown in FIG. 5, the thrust bearings 26, 2
7 may be omitted, and the sliding surfaces of these two may be coated with a highly slippery resin such as a fluororesin.
Further, as shown in FIG. 26, only the thrust bearing 26 may be omitted.

In addition, in the embodiment shown in FIGS. 14, 15 and 16, the contact position of the spring receiving member 71 on the valve body side with the valve body 16 and the valve seat member of the valve body 16 when the valve is closed. The distance L between the seat 14 and the seating position is smaller than the diameter D of the valve port 13 at this seating position, and the distance L is made as short as possible.

As a result, the occurrence of inclination of the valve element 16 with respect to the valve seat member 14 can be suppressed, and valve leakage can be reduced. Further, uneven wear of the valve seat member 14 due to repeated opening and closing of the valve can be reduced.

[0112]

As can be understood from the above description, according to the motor-operated valve of the present invention, since the rotor shaft and the valve holder are connected so as to be rotatable relative to each other, the frictional resistance between the valve holder and the guide hole is reduced. Even if it is large, the rotor shaft can rotate relative to the valve holder, thrust is generated by the rotation of the rotor, and the valve holder only displaces the guide hole in the axial direction when the valve is opened / closed, and does not have to rotate. Even if the outer diameter of the holder is increased, the driving force required for opening and closing the valve does not increase, and the valve can be opened and closed with low power.

Further, according to the motor-operated valve of the present invention, the spring receiving member guides the arrangement position of the compression coil spring in the valve holder to the center, and the mounting concentricity of the compression coil spring is improved. The resistance is reduced, and the valve body can evenly hit the valve seat without tilting, which prevents an unbalanced load from acting on the frictional engagement portion between the valve holder and its guide hole. Friction resistance at the time of opening / closing is reduced to improve the operating performance, the driving force required for opening / closing the valve is reduced, and the output torque of the stepping motor can be reduced as compared with the conventional one.

Further, since the valve body is displaceable in the radial direction with respect to the valve holder, a high degree of concentric mounting accuracy is not required when the valve holder and the valve seat member are assembled, and the valve body and the valve seat member are not required to be mounted. Concentricity is obtained.

[Brief description of drawings]

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

FIG. 2 is an enlarged vertical sectional view showing a main part of one embodiment of the motor-operated valve according to the present invention.

FIG. 3 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 4 is a vertical cross-sectional view showing an enlarged main part of one embodiment of the motor-operated valve according to the present invention.

FIG. 5 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 6 is a vertical cross-sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 7 is a vertical cross-sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 8 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 9 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 10 is a vertical cross-sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 11 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 12 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 13 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 14 is a vertical cross-sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 15 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 16 is a vertical cross-sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 17 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 18 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 19 is a longitudinal sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 20 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 21 is a longitudinal sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 22 is a vertical cross-sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 23 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 24 is a vertical cross-sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 25 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

FIG. 26 is a vertical sectional view showing another embodiment of the motor-operated valve according to the present invention.

[Explanation of symbols]

10 valve housing 14 valve seat member 16 valve body 18 valve holder 20 holding cylinder 26 Thrust bearing 29 Compression coil spring 31 Female thread member 33 Male thread 40 stepping motor 41 rotor shaft 43 rotor 44 rotor case 45 Stator element 52 guide support 53 Hanging cylinder 60 spiral guide wire 63 Movable stopper member 65 Bearing sleeve 71 Spring receiving member

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3H052 AA01 BA21 CD02 EA16                 3H062 AA02 AA12 BB04 CC02 EE08                       HH04 HH09

Claims (17)

[Claims] 1. A male screw portion formed on a rotor shaft of a stepping motor is screwed into a female screw hole of a female screw member fixed to a valve housing, and the screw shaft is displaced in the axial direction by the screw engagement. In an electrically operated valve that drives the valve element to open and close with respect to the valve seat portion by axial displacement of the rotor shaft, the valve is fitted in a guide hole provided on the valve housing side and supported so as to be slidable in the axial direction from the valve housing An electric motor, wherein the valve body is attached to the valve holder so as to be displaceable in a radial direction, and the valve holder and the rotor shaft are relatively rotatably connected to each other. valve. 2. The electrically operated valve according to claim 1, wherein the valve holder and the rotor shaft have thrust surfaces facing each other, and a thrust bearing is sandwiched between the thrust surfaces. 3. The electrically operated valve according to claim 2, wherein the thrust bearing is a metal washer having a highly slippery surface, a washer made of a highly slippery resin, or a washer having a highly slippery resin coating. 4. The valve holder has a cylindrical shape and supports the valve element at one end thereof so as to be displaceable in a radial direction, and has an end plate portion forming the thrust surface at the other end, A through hole is formed in the center of the end plate portion, the distal end portion of the rotor shaft penetrates through the through hole in a loosely fitted state, and the distal end portion of the rotor shaft located in the valve holder is A flange portion forming a thrust surface is provided, the thrust bearing is arranged between the end plate portion and the flange portion, and between a tip end portion of the rotor shaft in the valve holder and a back surface portion of the valve body. The motorized valve according to any one of claims 1 to 3, wherein a compression coil spring is attached to the. 5. A spring bearing member is sandwiched between one winding end of the compression coil spring and a tip end portion of the rotor shaft or / and the other winding end of the compression coil spring and a back surface portion of the valve body. The compression coil spring engages with the spring bearing member in a radially constrained state, and the spring bearing member engages with the tip end portion of the rotor shaft or the back surface portion of the valve body in a concavo-convex manner so that The motorized valve according to claim 4, wherein the motorized valve is guided to the center. 6. A spring bearing member is sandwiched between one winding end of the compression coil spring and a tip end portion of the rotor shaft or a back surface portion of the valve body, and the compression coil spring is the spring bearing member. To the center of the valve holder by engaging with the tip of the rotor shaft or the back surface of the valve body in a concavo-convex manner. The winding end is provided with a protruding line portion bent in the axial direction at the position of the spring axis, and the protruding line portion is formed on the back surface portion of the valve body or the tip end portion of the rotor shaft facing the protruding line portion. The motor-operated valve according to claim 4, which is engaged with the central small hole. 7. A spring bearing member is sandwiched between one winding end of the compression coil spring and a tip end portion of the rotor shaft or a rear surface portion of the valve body, and the compression coil spring is the spring bearing member. To the center of the valve holder by engaging with the tip of the rotor shaft or the back surface of the valve body in a concavo-convex manner. 5. The motor-operated valve according to claim 4, wherein the winding end is in the shape of a pick tail end and is in contact with the back surface of the valve body or the center of the tip of the rotor shaft facing the winding end. 8. The conical convex shape that the abutment portion of the pick-up end-shaped winding end of the compression coil spring engages with the pick-tail end-shaped winding end. Motorized valve. 9. The compression coil spring is formed of a conical coil spring, and a spring receiving member is sandwiched between a winding end on the large diameter side and a tip end portion of the rotor shaft or a back surface portion of the valve body. The compression coil spring engages with the spring bearing member in a radially restrained state, and the spring bearing member engages with the tip end portion of the rotor shaft or the back surface portion of the valve body in a concavo-convex manner to guide it to the center of the valve holder. 5. The motor-operated valve according to claim 4, wherein the winding end on the small diameter side of the compression coil spring is in contact with the back surface of the valve body or the center of the tip of the rotor shaft facing the winding end. . 10. A winding portion on the small diameter side of the compression coil spring, wherein a hemispherical convex portion is formed on a rear surface portion of the valve body or a tip end portion of the rotor shaft where a winding end on the small diameter side of the compression coil spring faces. The motor-operated valve according to claim 9, wherein an end engages with the hemispherical convex portion. 11. The motor-operated valve according to claim 5, wherein the spring receiving member has an extension shaft portion that guides an inner diameter portion of the compression coil spring. 12. An axial center hole is formed in the extension shaft-shaped portion of the spring bearing member, and a guide shaft-shaped portion extendedly formed on the spring receiving side facing the spring bearing member is axially formed in the shaft center hole. The motor-operated valve according to claim 11, wherein the motor-operated valve is slidably fitted to the. 13. The motor-operated valve according to claim 5, wherein the spring receiving member has an extension cylindrical portion that guides an outer diameter portion of the compression coil spring. . 14. The uneven engagement between the spring bearing member and the tip end portion of the rotor shaft or the back surface portion of the valve body is a planar engagement by a shallow dish-like unevenness. An electric valve according to any one of 1 to 13. 15. The concave-convex engagement between the spring bearing member and the tip end portion of the rotor shaft or the back surface portion of the valve body is a spherical engagement due to a substantially hemispherical concave-convex shape. An electric valve according to any one of 1 to 13. 16. The convex-concave engagement between the spring bearing member and the tip end portion of the rotor shaft or the rear surface portion of the valve body is a pivotal engagement due to a substantially conical concave-convex shape. An electric valve according to any one of 1 to 13. 17. The distance between the contact position of the spring receiving member provided on the valve body side with the valve body and the seating position of the valve body with the valve seat member when the valve is closed is the valve at this seating position. The motor-operated valve according to any one of claims 5 to 16, which is smaller than the port diameter.