Motor valve

Abstract

To provide a motor valve capable of improving the degree of freedom in controlling an on-off valve while securing a smaller size and a lighter weight.SOLUTION: The motor valve includes a valve body including a first flow path into which refrigerant is introduced, a second flow path out of which the refrigerant flows, a third flow path through which the refrigerant passes, and a valve seat formed between the first flow path and the second flow path, a valve stem body including a valve element part which can be seated on the valve seat, a motor arranged on the valve body on the opposite side to the valve seat across the third flow path, and a conversion mechanism for converting the rotation of a rotor of the motor into linear movement to be transmitted to the valve stem body.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a motor-operated valve. [Background technology]

[0002] For example, in the refrigeration cycle of an air conditioner mounted on an automobile, a temperature-sensing thermal expansion valve that adjusts the amount of refrigerant passing through according to temperature is used. Conventionally, such a thermal expansion valve employs a power element that drives a valve body by the pressure of a sealed working gas.

[0003] Generally, power elements are useful because they can use a simple mechanical structure to sense the refrigerant temperature and control the opening and closing of the expansion valve, but in recent refrigeration cycles, more flexible opening and closing valve control is desired, and for example, forced valve closing operation is sometimes required regardless of the refrigerant temperature.Therefore, a configuration has already been put into practical use in which a solenoid valve and an expansion valve are arranged in series in the refrigeration cycle and the flow of refrigerant passing through the expansion valve is blocked by the shutoff operation of the solenoid valve, but the use of two valve devices leads to an increase in the size of the structure.

[0004] In response to this, Patent Document 1 discloses an electric valve that is combined with a valve unit and a passage body and that can open and close the valve using a stepping motor of the valve unit. This electric valve can be used as an expansion valve in a refrigeration cycle, and by communicating with an external device, the stepping motor can be operated regardless of the temperature of the refrigerant to arbitrarily move the valve body toward and away from the valve seat of the passage body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2023-53708 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the motor-operated valve of Patent Document 1, the valve unit is disposed adjacent to a flow path provided in the passage body through which the high-pressure refrigerant flows. In this structure, the internal pressure of the can that covers the rotor, etc. increases when the high-pressure refrigerant is introduced, so that it is necessary to correspondingly improve the strength of the can and fastening members and the pressure resistance of the seals, etc., which leads to an increase in size and weight of the structure.

[0007] Therefore, an object of the present invention is to provide a motor-operated valve that can improve the degree of freedom in controlling the opening and closing of the valve while ensuring a small size and light weight. [Means for solving the problem]

[0008] In order to achieve the above object, the motor-operated valve according to the present invention comprises: a valve body including a first flow path into which a refrigerant is introduced, a second flow path through which the refrigerant flows out, a third flow path through which the refrigerant passes, and a valve seat formed between the first flow path and the second flow path; a valve stem having a valve body portion capable of being seated on the valve seat; a motor disposed in the valve body on an opposite side of the valve seat across the third flow path; and a conversion mechanism that converts the rotation of the rotor of the motor into linear movement and transmits the linear movement to the valve stem. Effect of the Invention

[0009] According to the present invention, it is possible to provide a motor-operated valve that can improve the degree of freedom in controlling the opening and closing of the valve while ensuring a small size and light weight. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of the motor-operated valve according to the first embodiment. [Diagram 2] FIG. 2 is a vertical cross-sectional view of the motor-operated valve of the first embodiment in a valve closed state. [Diagram 3] FIG. 3 is a vertical cross-sectional view of the motor-operated valve of the first embodiment in an open state. [Figure 4] FIG. 4 is a cross-sectional view showing the periphery of the motor unit used in the first embodiment. [Diagram 5] FIG. 5 is a vertical cross-sectional view of the motor-operated valve of the second embodiment in a valve closed state. [Figure 6] FIG. 6 is a vertical cross-sectional view of the motor-operated valve of the second embodiment in an open state. [Figure 7] FIG. 7 is a perspective view of an aligning member used in the second embodiment. [Figure 8] FIG. 8 is a vertical cross-sectional view of a holder according to a modified example. [Figure 9] FIG. 9 is a top view of the holder. [Figure 10] FIG. 10 is a vertical cross-sectional view of the motor-operated valve according to the third embodiment in a valve closed state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] (Direction definition) In this specification, the direction from the valve seat 20 to the motor unit 100 is defined as the "upward direction," and the opposite direction from the motor unit 100 to the valve seat 20 is defined as the "downward direction."

[0013] (First embodiment) Fig. 1 is a side view of the motor-operated valve 1 in this embodiment as viewed from the first flow path 21 side. Fig. 2 is a vertical cross-sectional view of the motor-operated valve 1 in a closed state, and Fig. 3 is a vertical cross-sectional view of the motor-operated valve 1 in an open state. Fig. 4 is a cross-sectional view showing the periphery of the motor unit 100.

[0014] 2 and 3, the motor-operated valve 1 includes a valve body 2, a valve stem 3, and a motor unit 100.

[0015] The valve body 2 includes a first flow path 21, a second flow path 22, a first connection path 21a, an orifice path 21b, a second connection path 22a, and a return flow path (third flow path) 23. The first flow path 21 and the first connection path 21a each extend perpendicular to the axis L, and the inner diameter of the first flow path 21 is larger than the inner diameter of the first connection path 21a. The second flow path 22 and the second connection path 22a each extend perpendicular to the axis L on the opposite side of the valve body 2 to the first flow path 21, and the inner diameter of the second flow path 22 is larger than the inner diameter of the second connection path 22a. The orifice path 21b extends along the axis L, and its lower end communicates with the first connection path 21a near the tip, and its upper end communicates with the second connection path 22a near the tip. The inside of the second connection passage 22a constitutes a valve chamber VC, and the upper end of the orifice passage 21b constitutes the valve seat 20. The return passage 23 extends between the motor unit 100 and the second passage 22 in a direction intersecting the axis L. The upper end of the valve body 2 is formed with a recess 2a that communicates with the return passage 23.

[0016] The first flow path 21 is a supply-side flow path connected to a condenser (not shown) of the refrigeration cycle, and high-pressure refrigerant is supplied to the orifice path 21b via the supply-side flow path. The second flow path 22 is a discharge-side flow path, and the fluid in the valve chamber VC is discharged to an evaporator (not shown) outside the motor-operated valve via the discharge-side flow path. The return flow path 23 introduces the refrigerant that has passed through the evaporator.

[0017] In the valve body 2, the stem insertion hole 28 extends upward from the second connection passage 22a along the axis L, slidably engages with the stem 3, and serves to guide the stem 3. In addition, the annular hole 27 formed above the stem insertion hole 28 and connected to the return passage 23 has a larger diameter than the stem insertion hole 28 and serves to accommodate the coil spring 4.

[0018] The metal valve stem 3, which is a single elongated rod-like member, is disposed along the axis L and passes through the valve chamber VC, the valve stem insertion hole 28, the annular hole 27, and the return flow passage 23. The lower end of the valve stem 3 is formed with a conical valve body portion 3a whose diameter decreases downward. As shown in FIG. 2, when the valve body portion 3a is seated on the valve seat 20 of the valve body 2, the flow of refrigerant through the orifice passage 21b is restricted. This state is called a non-communicating state. However, even when the valve stem 3 is seated on the valve seat 20, a restricted amount of refrigerant may flow. On the other hand, when the valve body portion 3a is separated from the valve seat 20 as shown in FIG. 3, the flow of refrigerant passing through the orifice passage 21b increases. This state is called a communicating state.

[0019] The valve stem 3 has a circumferential groove 3b in the annular hole 27. A C-shaped plate material (called a retaining ring) 41 is fitted into the circumferential groove 3b when viewed in the direction of the axis L. A coil spring 4 is arranged between the retaining ring 41 and the bottom wall of the annular hole 27, and biases the valve stem 3 upward via the retaining ring 41.

[0020] (Motor unit configuration) Next, the motor unit 100 will be described with reference to Figs. 2 to 4. The motor unit 100 is composed of a cylindrical can 50 with a top fixed to the valve body 2 via a cylindrical holder 11, a stator 55 fitted onto the can 50, a rotor 57 mounted inside the can 50, a generally cylindrical cover 9 with a top that covers the periphery of the stator 55, a gear-type reduction mechanism 6 that reduces the rotational speed of the rotor 57 and transmits it, and a screw drive member (also called a drive member) 58 that converts the rotational movement of the output gear of the reduction mechanism 6 into a linear movement via a screw feed mechanism 54 (Fig. 4) and transmits it to the valve stem 3. The can is a member having a cylindrical portion (the can 50 has a cylindrical portion with a bottom) that is attached to the valve body side of the motor-operated valve so that the inside is sealed. The can 50 houses the rotor 57, the reduction mechanism 6, the screw feed mechanism 54, etc. More precisely, a part of the screw feed mechanism 54 is housed in the can 50 , and the entire screw feed mechanism 54 is housed in the connection between the can 50 and the holder 11 .

[0021] The stepping motor 5 is disposed inside the can 50 so as to be rotatable relative to the can 50, and has a rotor 57 with a rotor support member 56 fixed to the upper inside thereof. The stepping motor 5 consists only of the rotor 57, and does not include a stator 55. The stator 55, which is composed of a yoke 51, a bobbin 52, a coil 53, etc., is fitted and fixed to the outside of the can 50, and is covered by a resin cover 9. The cover 9 has a connector portion 9a. The connector portion 9a is formed along the axis of the return flow path 23, and a terminal T connected to a stepping motor driving circuit board (not shown) is disposed inside the connector portion 9a.

[0022] The holder 11 is composed of a cylindrical main body 11a and a flange portion 11b that extends radially outward from the upper end of the main body 11a and is joined to the lower end of the can 50. A male thread 11c is formed on the outer periphery of the lower part of the main body 11a. The male thread 11c is screwed into a female thread 2b formed on the inner periphery of a recess 2a of the valve main body 2, thereby fixing the can 50 to the valve main body 2 via the holder 11. The gap between the main body 11a and the recess 2a is sealed by an O-ring OR1.

[0023] The threaded bearing member 13 is fitted into the upper inner periphery of the holder 11 by press fitting. The threaded bearing member 13 has a through hole 13a extending along the axis L and a communication hole 13b extending from the lower end of the through hole 13a parallel to the axis L and opening at the outer periphery. The communication hole 13b has a function of introducing the refrigerant flowing from the return flow passage 23 through the recess 2a to the lower side of the threaded bearing member 13 into the can 50. A thin-walled cylindrical body 66 is fixed to the outer periphery of the upper end of the threaded bearing member 13. A stepped cylindrical output shaft portion 29 is rotatably fitted into the upper part of the through hole 13a of the threaded bearing member 13.

[0024] 4, the reduction mechanism 6 includes a sun gear 61 formed integrally with the rotor support member 56 on the inner peripheral side of the rotor 57, a fixed ring gear 62 fixed to the valve body 2 via a thin-walled cylindrical body 66, a planetary gear 63 disposed between the sun gear 61 and the fixed ring gear 62 and meshing with them, a carrier 64 that rotatably supports the planetary gear 63, and a cylindrical output gear member 65 with a bottom that has teeth on its inner peripheral side that mesh with the planetary gear 63, which together form a paradox planetary gear reduction mechanism. The number of teeth of the fixed ring gear 62 is set to be different from the number of teeth of the output gear member 65.

[0025] The shaft member 8 passes through the rotor support member 56 and the sun gear 61 and rotatably holds them, and the upper end of the shaft member 8 is supported by a support member 81 arranged on the inside top of the can 50.

[0026] The upper part of the output shaft portion 29 is press-fitted into the central opening at the bottom of the output gear member 65, and the lower end of the shaft member 8 is rotatably fitted into the upper opening of this output shaft portion 29.

[0027] A male threaded portion 58a formed on the lower portion of a screw drive member 58 is screwed into a female threaded portion 13c formed on the lower portion of the through hole 13a of the screw bearing member 13. The rotational movement of the output gear member 65 (the decelerated rotational movement of the rotor 57) is converted into linear movement along the axis L by a screw feed mechanism (conversion mechanism) 54 consisting of the male threaded portion 58a and the female threaded portion 13c.

[0028] A slit 29a is formed at the lower end of the output shaft portion 29, and a blade 58b protruding along the axis L is formed at the upper end of the screw drive member 58, with the slit 29a and the blade 58b slidably engaging with each other. As a result, the output shaft portion 29 is connected to the screw drive member 58 so as to be rotatable together with it, and when the output gear member 65 (rotor 57) rotates, the output shaft portion 29 and the screw drive member 58 rotate together with it, but are capable of linear movement along the axis L relative to each other.

[0029] A metallic ball 15 is coaxially welded to the lower end of the screw drive member 58. Meanwhile, a circular hole 3c is formed in the upper end of the valve shaft 3, and a metallic ball seat 16 is press-fitted into the circular hole 3c. The enlarged upper end surface 16a of the ball seat 16 is formed into a spherical curved surface (specifically, a shape combining a cone and a sphere) and slidably holds the ball 15.

[0030] (Assembly of motor-operated valve) The assembly process of the motor-operated valve 1 will be described. First, the retaining ring 41 is attached to the valve shaft 3. Then, with the rotor 57, the reduction gear mechanism 6, etc. attached inside the can 50, a rotor assembly is prepared in which the holder 11 is fixed to the lower end of the can 50.

[0031] The coil spring 4 is inserted from above into the annular hole 27 of the machined valve body 2, and then the valve stem 3 is inserted from above through the recess 2a and the inside of the coil spring 4 into the valve stem insertion hole 28. At this time, the upper end of the coil spring 4 comes into contact with the lower surface of the retaining ring 41.

[0032] Thereafter, an O-ring OR1 is placed in the inner circumferential groove of the recess 2a, an O-ring OR2 is placed at the open end of the recess 2a, and the male thread 11c of the holder 11 is screwed into the female thread 2b of the recess 2a of the valve body 2 to attach the rotor assembly to the valve body 2. At this time, the O-ring OR1 exerts a sealing mechanism between the body 11a of the holder 11 and the recess 2a. The flange portion 11b prevents the O-ring OR2 from falling off. The O-ring OR2 may be placed in the holder 11 before the holder 11 is screwed into the valve body 2, or may be inserted from the top of the can after the holder 11 is screwed into the valve body 2 and assembled.

[0033] From this state, the cover 9 together with the stator 55 is brought closer to the can 50 from above, covering the can 50. With the lower end of the cover 9 positioned on the upper surface side of the valve body 2, an O-ring OR2 is placed between the cover 9 and the holder 11, sealing the space between them. A plate-shaped stay 18 is placed between the lower end of the cover 9 and the side surface of the valve body 2, and the two are fixed together by screws SC. When the connector part 9a of the cover 9 is connected to a connector (not shown), an external control device and the circuit board of the motor-operated valve 1 are connected via terminal T so as to be able to transmit signals.

[0034] (Operation of motor-operated valve) When the rotor 57 of the stepping motor 5 is rotated in one direction by supplying a valve-closing control signal with a predetermined number of pulses to the stator 55 from an external control device, the rotational speed is input from the sun gear 61 to the reduction mechanism 6, and the rotational speed reduced by the reduction mechanism 6 is transmitted to the screw drive member 58 via the output shaft 29. When the screw drive member 58 rotates in one direction, the female thread portion 13c and the male thread portion 58a screw relative to each other, and the screw drive member 58 moves downward in the direction of the axis L according to the rotational speed.

[0035] When the screw drive member 58 rotates together with the ball 15 and descends, a rotational slide occurs between the ball 15 and the upper end surface 16a of the ball seat 16, and the valve shaft 3 is urged downward via the ball seat 16. The valve shaft 3 descends against the urging force of the coil spring 4, and the valve body portion 3a seats on the valve seat 20 to close the valve. As a result, the refrigerant introduced into the first flow path 21 from a condenser (not shown) cannot enter the valve chest VC from the orifice passage 21b, and the flow of the refrigerant is interrupted between the first flow path 21 and the second flow path 22.

[0036] On the other hand, when the rotor 57 of the stepping motor 5 is rotated in the other direction by supplying a valve-opening control signal to the stator 55 from a control device (not shown), the screw drive member 58 moves upward in the direction of the axis L via the reduction mechanism 6 and the screw feed mechanism 54. As a result, the driving force that urges the valve stem 3 downward disappears, and the valve stem 3 rises according to the urging force of the coil spring 4. When the valve stem 3 rises, the valve body portion 3a separates from the valve seat 20 to open the valve. As a result, the refrigerant enters the valve chamber VC from the first flow path 21 through the first connection path 21a and the orifice path 21b, and further flows out of the motor-operated valve 1 through the second connection path 22a and the second flow path 22. For example, the valve-opening control signal supplied to the stator 55 is determined according to a signal from a temperature sensor attached to the outlet side piping of the evaporator, and the opening / closing valve operation and the amount of refrigerant passing through the orifice path 21b when the valve is opened are controlled by this.

[0037] The refrigerant discharged from the second flow path 22 passes through an evaporator (not shown), then enters the return flow path 23 of the electric valve 1 at a relatively low pressure, and after flowing out of the electric valve 1, reaches a compressor (not shown), where it is pressurized as necessary and supplied to the condenser.

[0038] According to this embodiment, the valve seat 20 is sandwiched between the orifice passage 21b and the valve chamber VC, and the valve body 3a is always subjected to pressure in the valve opening direction, which is called a forward flow. However, since the reduction mechanism 6 having a high reduction ratio is disposed between the stepping motor 5 and the valve stem 3, the position of the valve body 3a can be reliably controlled both when the valve is closed and when the valve is opened, regardless of the pressure applied to the valve body 3a. However, the motor-operated valve 1 of this embodiment can also be used in the case of a reverse flow, where the valve seat 20 is sandwiched between the orifice passage 21b and the valve chamber VC, and the refrigerant is introduced from the condenser into the second flow path 22, and the refrigerant flows out from the first flow path 21 toward the evaporator.

[0039] The can 50 is disposed on the opposite side of the valve seat 20 across the return flow passage 23, and low-pressure refrigerant is supplied into the inside of the can 50 from the adjacent return flow passage 23 through the recess 2a and the communication hole 13b. Therefore, while the supplied refrigerant is used to lubricate the reduction gear mechanism 6, the thickness of the can 50 can be made relatively thin, the strength of each screw portion can be relatively suppressed, and O-rings OR1 and OR2 with relatively low pressure resistance can be used, which contributes to the miniaturization, weight reduction, and cost reduction of the motor-operated valve 1.

[0040] Furthermore, according to this embodiment, since the shape of the valve body 2 is almost the same as the shape of the valve body of a conventional expansion valve equipped with a power element, it is possible to replace the electric valve of this embodiment in a refrigeration cycle that is already in use without requiring major design changes.

[0041] Second embodiment Fig. 5 is a vertical cross-sectional view of the motor-operated valve 1A according to the second embodiment in a closed state, and Fig. 6 is a vertical cross-sectional view of the motor-operated valve 1A in an open state. This embodiment differs from the above-mentioned embodiment in that the configurations of the valve body 2A and the valve shaft 3A are changed and a guide member 12A and an aligning member 19A are added, but the other configurations are the same, so the same reference numerals are used and repeated explanations will be omitted.

[0042] The valve body 2A differs only in that the annular hole portion 27A has a lower hole portion 27Aa and an upper hole portion 27Ab having a larger diameter than the lower hole portion 27Aa. Since the other configurations are the same, a duplicated description will be omitted.

[0043] A coil spring 4 is disposed in the lower hole portion 27Aa, and an aligning member 19A is disposed in the upper hole portion 27Ab.

[0044] FIG. 7 is a perspective view of the aligning member 19A. The aligning member 19A can be formed, for example, by press-molding a metal plate material. Specifically, a long and thin plate material is rolled into a cylindrical shape, and both ends are overlapped to form the peripheral wall 19Aa. In addition, the peripheral wall 19Aa is cut and raised in multiple places (three places in this case) along the circumferential direction to form rectangular tongue pieces 19Ab, and one end connected to the peripheral wall 19Aa is bent radially inward from the starting point. A hemispherical protrusion 19Ac is formed near the tip of each tongue piece 19Ab, protruding toward the center of the peripheral wall 19Aa. In this way, the aligning member 19A is formed.

[0045] Since the outer diameter of peripheral wall 19Aa in a free state is larger than the inner diameter of upper hole portion 27Ab, when peripheral wall 19Aa is inserted into upper hole portion 27Ab, it elastically deforms and contracts in diameter, and the elastic force urges the outer periphery of peripheral wall 19Aa toward the inner periphery of upper hole portion 27Ab, and the frictional force generated thereby attaches aligning member 19A to upper hole portion 27Ab. Note that a crimp or other processing may be added to the upper end of upper hole portion 27Ab to prevent aligning member 19A from falling out.

[0046] 5 and 6, a cylindrical guide member 12A is disposed inside the holder 11. The guide member 12A is composed of an upper cylindrical portion 12Aa and a lower cylindrical portion 12Ab, which is smaller in diameter than the upper cylindrical portion 12Aa, which are coaxially connected to each other, and the lower cylindrical portion 12Ab is press-fitted into the bottom wall opening of the recess 2a of the valve body 2A. The guide member 12A also has a cylindrical through hole 12Ac that penetrates vertically.

[0047] The valve stem body 3A is composed of a lower shaft 31A, which is a first shaft, and an upper shaft 32A, which is a second shaft. The metal lower shaft 31A, which is a long, rod-like shape, is disposed along the axis L and penetrates the valve chamber VC of the valve body 2A, the valve stem insertion hole 28, and the lower hole portion 27Aa.

[0048] A conical valve body portion 31Aa is formed at the lower end of the lower shaft 31A, the diameter of which decreases as it extends downward, and a circumferential groove 31Ab is formed on the outer periphery of the lower shaft 31A, with which a retaining ring 41 engages. Furthermore, a conical seat 31Ac is formed at the upper end of the lower shaft 31A, the diameter of which decreases as it extends downward.

[0049] The upper shaft 32A is formed by connecting a small diameter portion 32Aa arranged in the upper hole portion 27Ab and a large diameter portion 32Ab arranged in the return flow passage 23 and the recess 2a and having a larger diameter than the small diameter portion 32Aa. The lower end of the small diameter portion 32Aa is spherical. The large diameter portion 32Ab slidably fits into the through hole 12Ac of the guide member 12A. The ball seat 16, which is approximately spherical, is press-fitted into the recess 32Ac formed at the upper end of the large diameter portion 32Ab. The hardness (e.g., Vickers hardness) of the ball 15 and the ball seat 16 is higher than the hardness of the upper shaft 32A and the lower shaft 31A.

[0050] With ball 15 abutting against ball seat 16, screw driving member 58 and upper shaft 32A are coupled (abut) so as to be capable of transmitting a driving force along axis L. With the lower end of small diameter portion 32Aa abutting against conical seat 31Ac, upper shaft 32A and lower shaft 31A are coupled (abut) so as to be capable of transmitting a driving force along axis L. By abutting the hemispherical lower end of small diameter portion 32Aa against conical seat 31Ac, coaxiality between upper shaft 32A and lower shaft 31A can be ensured.

[0051] The contact surface diameter A between the ball seat 16 and the ball 15 is smaller than the contact surface diameter B between the lower end of the small diameter portion 32Aa and the conical seat 31Ac (A <B)。

[0052] In the assembly process of the electric valve 1A, first, the retaining ring 41 is attached to the lower shaft 31A, and then, as in the above-described embodiment, a rotor assembly is prepared in which the holder 11 is fixed to the lower end of the can 50 with the rotor 57, reduction mechanism 6, etc., assembled inside the can 50.

[0053] The coil spring 4 is inserted from above into the machined lower hole portion 27Aa of the valve body 2A, and then the lower shaft 31A is passed from above through the recess 2a and the inside of the coil spring 4 and inserted into the valve shaft insertion hole 28. At this time, the upper end of the coil spring 4 abuts against the lower surface of the retaining ring 41.

[0054] Thereafter, the aligning member 19A is inserted into the upper hole portion 27Ab, and the guide member 12A is press-fitted into the bottom wall opening of the recess 2a to assemble. Furthermore, the upper shaft 32A is brought close from above the guide member 12A and passed through the through hole 12Ac, inserting the small diameter portion 32Aa into the aligning member 19A, and bringing its lower end into contact with the conical seat 31Ac of the lower shaft 31A. At this time, the three tongue pieces 19Ab of the aligning member 19A elastically deform and the convex portion 19Ac comes into contact with the outer periphery of the small diameter portion 32Aa, thereby exerting a so-called aligning function to prevent the small diameter portion 32Aa from shifting relative to the axis L.

[0055] Thereafter, the motor-operated valve 1A is completed by attaching the rotor assembly in the same manner as in the first embodiment. Note that the first embodiment may be provided with an aligning member 19A for aligning the valve stem.

[0056] (Operation of motor-operated valve) When the rotor 57 of the stepping motor 5 is rotated in one direction by supplying a valve-closing control signal with a predetermined number of pulses from an external control device to the stator 55, the rotational speed reduced by the reduction mechanism 6 is transmitted to the screw drive member 58 via the output shaft portion 29, and the screw drive member 58 moves downward in the direction of the axis L.

[0057] The screw drive member 58 rotates together with the ball 15 and descends, and the downward driving force is transmitted to the lower shaft 31A via the upper shaft 32A, and the valve body portion 31Aa seats on the valve seat 20 to close the valve. At this time, since the contact surface diameter A between the ball seat 16 and the ball 15 is smaller than the contact surface diameter B between the lower end of the small diameter portion 32Aa and the conical seat 31Ac, relative rotation occurs mainly between the ball seat 16 and the ball 15, and relative rotation between the upper shaft 32A and the lower shaft 31A is unlikely to occur. Therefore, eccentricity (misalignment) with respect to the axis L due to whirling of the lower shaft 31A can be suppressed, and therefore the adhesion between the valve body portion 31Aa and the valve seat 20 can be improved. In addition, since the ball seat 16 and the ball 15 are made of a material with a relatively high hardness, wear can be suppressed even if relative sliding occurs.

[0058] On the other hand, when a valve-opening control signal is supplied from a control device (not shown) to the stator 55 to rotate the rotor 57 of the stepping motor 5 in the other direction, the screw driving member 58 moves upward in the direction of the axis L via the speed reducing mechanism 6 and the screw feed mechanism 54. As a result, the driving force biasing the upper shaft 32A downward disappears, so that the lower shaft 31A rises in accordance with the biasing force of the coil spring 4, and the valve body portion 31Aa separates from the valve seat 20 to enter an open state.

[0059] (Modification) Fig. 8 is a vertical cross-sectional view of a holder 11B according to a modified example, and Fig. 9 is a top view of the holder 11B. The holder 11B of this modified example can be used in place of the holder 11 and the guide member 12A of the second embodiment.

[0060] The holder 11B, which is a restricting member, is made up of a cylindrical main body 11Ba, a flange portion 11Bb extending radially outward from the upper end of the main body 11Ba and joined to the can 50, and a bottom wall 11Bd extending radially inward from the upper end of the main body 11Ba. A male thread 11Bc is formed on the outer periphery of the lower part of the main body 11Ba, and an opening 11Be is formed in the center of the bottom wall 11Bd. The holder 11B of this modification is also fixed to the valve body 2 by screwing the male thread 11Bc into a female thread 2b formed on the inner periphery of a recess 2a formed on the upper end of the valve body 2 shown in Figures 5 and 6.

[0061] The inner circumference of the opening 11Be has a shape in which a part of the cylindrical surface along the circumferential direction is connected in a short-circuit manner by one plane parallel to the axis L, that is, the opening 11Be has a D-shape (non-cylindrical shape) when viewed in the direction of the axis L. The outer circumference of the large diameter part 32Ab of the upper shaft 32A used in this modification is also not completely cylindrical, but has a D-shape (corresponding non-cylindrical shape) when viewed in the direction of the axis L corresponding to the opening 11Be. The non-cylindrical shape is not limited to the above, and may be, for example, a shape in which a part of the cylindrical surface along the circumferential direction is connected in a short-circuit manner by two planes parallel to the axis L. Here, the holder 11B and the upper shaft 32A constitute a rotation limiting mechanism.

[0062] When the upper shaft 32A is inserted into the opening 11Be of the holder 11B, the upper shaft 32A is guided by the opening 11Be and displaced along the direction of the axis L, but is unable to rotate around the axis L. Therefore, even if the screw drive member 58 rotates, the rotation of the upper shaft 32A can be prevented (limited), thereby preventing misalignment of the upper shaft 32A and also suppressing misalignment of the lower shaft 31A.

[0063] In addition, the through hole 12Ac of the guide member 12A in the second embodiment may be made to have a similar non-cylindrical shape, so that the guide member 12A can serve as a limiting member, and in such a case, the large diameter portion 32Ab of the upper shaft 32A may be made to have a similar non-cylindrical shape to similarly configure a rotation limiting mechanism, which can suppress misalignment of the upper shaft 32A during opening and closing of the valve. Such a rotation limiting mechanism consisting of a guide member and a holder into which a non-cylindrical valve shaft is fitted can also be used in the first embodiment.

[0064] (Third embodiment) 10 is a vertical cross-sectional view of a motor-operated valve 1C according to a third embodiment in a closed state. This embodiment differs from the first embodiment in that the configurations of a valve body 2C, a valve stem 3C, and a holder 11C are changed, and an aligning member 19A is added. Since the other configurations are the same, the same reference numerals are used and repeated explanations are omitted.

[0065] The valve body 2C is different only in that the annular hole 27C is shortened in the axial direction and an aligning member 19A is disposed therein instead of the coil spring 4. The rest of the configuration is the same as in the first embodiment, so a duplicated description will be omitted. The aligning member 19A is the same as that used in the second embodiment.

[0066] The valve stem body 3C differs only in that the circumferential groove 3Cb is shifted upward from the return flow passage 23, and other configurations are the same as those of the first embodiment, so that a duplicated description will be omitted.

[0067] The holder 11C is made up of a cylindrical main body 11Ca, a flange portion 11Cb extending radially outward from the upper end of the main body 11Ca and joined to the lower end of the can 50, and a bottomed cylindrical holding portion 11Cd joined to the lower end of the main body 11Ca. A male screw 11Cc is formed on the outer periphery of the lower part of the main body 11Ca. The configuration of the holder 11C other than the holding portion 11Cd is the same as that of the first embodiment, so a duplicated description will be omitted.

[0068] The bottom wall of the retaining portion 11Cd has a through hole 11Ce in its center into which the valve stem 3C is slidably fitted. A retaining ring 41 is engaged with a circumferential groove 3Cb of the valve stem 3C formed radially inward of the main body 11Ca. A coil spring (also simply called a spring) 4 is arranged in a compressed state around the valve stem 3C between the retaining ring 41 and the bottom wall of the retaining portion 11Cd, thereby biasing the valve stem 3C in the valve closing direction.

[0069] The motor-operated valve 1C of this embodiment is configured such that, instead of forming an accommodation portion for the coil spring 4 in the valve body 2C, a holding portion 11Cd is disposed in a part of the holder 11C as an accommodation portion for the coil spring 4. With this configuration, the valve stem 3C, the valve body 2C, and the motor unit 100 (excluding the stator unit) can be handled as a single module. Therefore, the single module can be preassembled and attached to the valve body 2C in one step, improving the ease of assembly.

[0070] The present invention is not limited to the above-described embodiment. Any of the components of the above-described embodiment may be modified within the scope of the present invention. Any of the components may be added or omitted in the above-described embodiment. For example, the example in which a planetary gear mechanism is used as the reduction mechanism has been shown, but the present invention is not limited to this, and a gear pair may be used. In the present embodiment, the axis of the valve stem intersects with the axis of the return flow passage, but the axis of the valve stem does not have to intersect with the axis of the return flow passage, and the valve stem does not have to intersect with the return flow passage itself.

[0071] This specification includes the disclosure of the following inventions. (First aspect) a valve body including a first flow path into which a refrigerant is introduced, a second flow path through which the refrigerant flows out, a third flow path through which the refrigerant passes, and a valve seat formed between the first flow path and the second flow path; a valve stem having a valve body portion capable of being seated on the valve seat; a motor disposed in the valve body on an opposite side of the valve seat across the third flow path; a conversion mechanism that converts the rotation of the rotor of the motor into a linear movement and transmits the linear movement to the valve shaft. A motor-operated valve.

[0072] (Second aspect) a rotor of the motor, a reduction mechanism that reduces the speed of rotation of the rotor of the motor, a conversion mechanism that converts the rotation reduced by the reduction mechanism into linear motion, and a can that accommodates at least the reduction mechanism; The inside of the can is in communication with the third flow path. 10. The motor-operated valve according to claim 1,

[0073] (Third aspect) a drive member that rotates and displaces in an axial direction, and a ball seat that is fixed to the valve shaft and has a spherical end are disposed between the conversion mechanism and the valve shaft; A ball fixed to the driving member abuts against an end of the ball seat, whereby axial displacement of the driving member is transmitted to the valve shaft. The motor-operated valve according to the first or second aspect,

[0074] (Fourth aspect) a rotation limiting mechanism for limiting rotation of the valve stem relative to the valve body, A motor-operated valve according to a third aspect,

[0075] (Fifth aspect) The rotation limiting mechanism includes a limiting member fixed to the valve body and having a non-cylindrical opening, and the valve shaft body having a non-cylindrical shape that engages with the opening. A fourth aspect of the motor-operated valve.

[0076] (Sixth aspect) the valve shaft body includes a first shaft having the valve body portion seated on the valve seat, and a second shaft connected to the first shaft and having the ball seat, The hardness of the material of the ball seat is higher than the hardness of the material of the first shaft and the second shaft. The motor-operated valve according to any one of the first to fifth aspects, characterized in that

[0077] (Seventh aspect) an end of the first shaft has a conical shape, an end of the second shaft has a spherical shape, and the conical end and the spherical end abut each other; a contact surface diameter between the ball and the ball seat is smaller than a contact surface diameter between the conical end and the spherical end; A sixth aspect of the motor-operated valve.

[0078] (Eighth aspect) The valve shaft is made of a single rod-shaped member, an aligning member attached to the valve body and abutting against an outer periphery of the valve stem at a plurality of points along a circumferential direction to apply an elastic force; The motor-operated valve according to any one of the first to fifth aspects, characterized in that

[0079] (Ninth aspect) A cylindrical holder is provided to fix a screw bearing member having a female thread constituting the conversion mechanism to the valve body, The holder has a holding portion that holds a spring that biases the valve shaft in a valve closing direction. The motor-operated valve according to any one of the first to eighth aspects, characterized in that

[0080] (Tenth Aspect) The motor-operated valve is used in a refrigeration cycle, A refrigerant from a condenser is introduced into the first flow path, a refrigerant flows out from the second flow path toward an evaporator, and a refrigerant from the evaporator passes through the third flow path. The motor-operated valve according to any one of the first to ninth aspects, characterized in that [Explanation of symbols]

[0081] 1, 1A: Motor valve 2, 2A: Valve body 3, 3A: Valve stem body 3a, 31Aa: Valve body part 4: Coil spring 5: Stepping motor 6: Reduction mechanism 20: Valve seat 21: First flow path 22: Second flow path 23: Return flow path (third flow path) 27: Annular hole 31A: Lower shaft 32A: Upper axis 50:Can 55: Stator 57: Rotor 100: Motor unit VC: Valve chamber

Claims

1. a valve body including a first flow path into which a refrigerant is introduced, a second flow path through which the refrigerant flows out, a third flow path through which the refrigerant passes, and a valve seat formed between the first flow path and the second flow path; a valve stem having a valve body portion capable of being seated on the valve seat; a motor disposed in the valve body on an opposite side of the valve seat across the third flow path; a conversion mechanism that converts the rotation of the rotor of the motor into a linear movement and transmits the linear movement to the valve shaft. A motor-operated valve.

2. a rotor of the motor, a reduction mechanism that reduces the speed of rotation of the rotor of the motor, a conversion mechanism that converts the rotation reduced by the reduction mechanism into linear motion, and a can that accommodates at least the reduction mechanism, The inside of the can is in communication with the third flow path.

2. The motor-operated valve according to claim 1 .

3. a drive member that rotates and displaces in an axial direction, and a ball seat that is fixed to the valve shaft and has a spherical end are disposed between the conversion mechanism and the valve shaft; A ball fixed to the driving member abuts against an end of the ball seat, whereby axial displacement of the driving member is transmitted to the valve shaft.

2. The motor-operated valve according to claim 1 .

4. a rotation limiting mechanism for limiting rotation of the valve stem relative to the valve body, 4. The motor-operated valve according to claim 3.

5. The rotation limiting mechanism includes a limiting member fixed to the valve body and having a non-cylindrical opening, and the valve shaft body having a non-cylindrical shape that engages with the opening.

5. The motor-operated valve according to claim 4.

6. the valve shaft body includes a first shaft having the valve body portion seated on the valve seat, and a second shaft connected to the first shaft and having the ball seat, the hardness of the material of the ball seat is higher than the hardness of the material of the first shaft and the second shaft; 4. The motor-operated valve according to claim 3.

7. an end of the first shaft having a conical shape and an end of the second shaft having a spherical shape, the conical end and the spherical end being in contact with each other; a contact surface diameter between the ball and the ball seat is smaller than a contact surface diameter between the conical end and the spherical end; 7. The motor-operated valve according to claim 6.

8. The valve shaft is made of a single rod-shaped member, an aligning member attached to the valve body and abutting against an outer periphery of the valve stem at a plurality of points along a circumferential direction to apply an elastic force; 4. The motor-operated valve according to claim 3.

9. A cylindrical holder is provided to fix a screw bearing member having a female thread constituting the conversion mechanism to the valve body, The holder has a holding portion that holds a spring that biases the valve shaft in a valve closing direction.

2. The motor-operated valve according to claim 1 .

10. The motor-operated valve is used in a refrigeration cycle, A refrigerant from a condenser is introduced into the first flow path, a refrigerant flows out from the second flow path toward an evaporator, and a refrigerant from the evaporator passes through the third flow path.

2. The motor-operated valve according to claim 1 .

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