Electric valve

Abstract

Provided is an electrically operated valve which can ensure small size and light weight and can improve the degree of freedom of opening and closing valve control. The electrically operated valve includes: 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 shaft body which is provided with a valve core part that can be seated on the valve seat; a motor disposed on the valve main body on the opposite side of the third flow path from the valve seat; and a conversion mechanism that converts rotation of a rotor of the electric motor into linear movement and transmits the linear movement to the valve shaft body.

Description

Technical Field

[0001] The present invention relates to an electric valve. Background Art

[0002] For example, in the refrigeration cycle of an air conditioning device mounted on a vehicle, a temperature-sensing thermostatic expansion valve that adjusts the flow rate of the refrigerant according to temperature is used. In such a thermostatic expansion valve, a power element that drives a valve element based on the pressure of the enclosed working gas has been conventionally used.

[0003] Generally, the power element is useful in that it can control the opening and closing of the expansion valve by simply mechanically sensing the temperature of the refrigerant. However, in recent refrigeration cycles, a higher degree of freedom in opening and closing valve control is desired. For example, a forced valve closing operation is also required regardless of the temperature of the refrigerant. Therefore, in the refrigeration cycle, a structure in which a solenoid valve is arranged in series with the expansion valve and the flow of the refrigerant through the expansion valve is cut off by the closing operation of the solenoid valve has been put into practical use. However, the use of two valve devices has led to an increase in the size of the structure.

[0004] On the other hand, Patent Document 1 discloses an electric valve composed of a combination of a valve unit and a passage main body, and uses a stepping motor of the valve unit to perform an opening and closing valve operation. This electric valve can be used as an expansion valve in a refrigeration cycle, and can communicate with an external device to operate the stepping motor regardless of the temperature of the refrigerant, so that the valve element can be brought into contact with and separated from the valve seat of the passage main body arbitrarily.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2023-53708

[0008] Technical Problem to be Solved by the Invention

[0009] However, in the electric valve of Patent Document 1, the valve unit is arranged in contact with the flow path through which the high-pressure refrigerant flowing through the passage main body flows. In this structure, the internal pressure of the case covering the rotor etc. increases due to the introduction of the high-pressure refrigerant. Therefore, it is necessary to correspondingly increase the strength of the case and the fastening members, improve the pressure resistance of the seal, etc., resulting in an increase in the size and weight of the structure. Summary of the Invention

[0010] Therefore, an object of the present invention is to provide an electric valve that can ensure small size and light weight, and can improve the degree of freedom in opening and closing valve control.

[0011] Technical Means for Solving the Technical Problem

[0012] To achieve the above object, the electric valve of the present invention includes:

[0013] A valve body having 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;

[0014] A valve shaft body having a valve core portion that can be seated on the valve seat;

[0015] A motor disposed on the valve body on the opposite side of the valve seat across the third flow path; and

[0016] A conversion mechanism that converts the rotation of the rotor of the motor into linear movement and transmits it to the valve shaft body.

[0017] Effects of the Invention

[0018] According to the present invention, an electric valve can be provided that can ensure small size and light weight and can improve the degree of freedom of on-off valve control. Description of the Drawings

[0019] Figure 1 A side view of the electric valve in the first embodiment.

[0020] Figure 2 A longitudinal sectional view of the electric valve in the first embodiment in the closed valve state.

[0021] Figure 3 A longitudinal sectional view of the electric valve in the first embodiment in the open valve state.

[0022] Figure 4 A sectional view showing the periphery of the motor unit for the first embodiment.

[0023] Figure 5 A longitudinal sectional view of the electric valve in the second embodiment in the closed valve state.

[0024] Figure 6 A longitudinal sectional view of the electric valve in the second embodiment in the open valve state.

[0025] Figure 7 A perspective view of the core adjustment member for the second embodiment.

[0026] Figure 8 A longitudinal sectional view of the cage according to the modification.

[0027] Figure 9 A top view of the cage.

[0028] Figure 10 A longitudinal sectional view of the electric valve according to the third embodiment in the closed valve state. Detailed implementation manners

[0029] Hereinafter, with reference to the drawings, the implementation manners of the present invention will be described.

[0030] (Definition of directions)

[0031] In this specification, the direction from the valve seat 20 toward the motor unit 100 is defined as the "upward direction", and the opposite direction, from the motor unit 100 toward the valve seat 20, is defined as the "downward direction". The axis of the electric valve 1 is set as L.

[0032] (First embodiment)

[0033] Figure 1 is a side view of the electric valve 1 in this embodiment as viewed from the first flow path 21. Figure 2 is a longitudinal sectional view of the electric valve 1 in the closed valve state, Figure 3 is a longitudinal sectional view of the electric valve 1 in the open valve state. Figure 4 is a sectional view showing the periphery of the motor unit 100.

[0034] In Figure 2 and Figure 3 the electric valve 1 includes a valve body 2, a valve shaft body 3, and a motor unit 100.

[0035] The valve body 2 includes a first flow path 21, a second flow path 22, a first connection path 21a, a hole 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 extend orthogonally to the axis L respectively, and the inner diameter of the first flow path 21 is larger than the inner diameter of the first connection path 21a. In addition, the second flow path 22 and the second connection path 22a extend orthogonally to the axis L on the opposite sides of the valve body 2 with respect to the first flow path 21 respectively, and the inner diameter of the second flow path 22 is larger than the inner diameter of the second connection path 22a. The hole path 21b extends along the axis L, and its lower end communicates with the vicinity of the top end of the first connection path 21a, and its upper end communicates with the vicinity of the top end of the second connection path 22a. A valve chamber VC is formed in the second connection path 22a, and the upper end of the hole path 21b forms a valve seat 20. The return flow path 23 extends in a direction intersecting the axis L between the motor unit 100 and the second flow path 22. A recess 2a communicating with the return flow path 23 is formed at the upper end of the valve body 2.

[0036] 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 hole path 21b through 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 electric valve through the discharge-side flow path. The refrigerant after passing through the evaporator is introduced into the return flow path 23.

[0037] In the valve body 2, the valve shaft insertion hole 28 extends upward along the axis L from the second connection path 22a and slidably engages with the valve shaft body 3, having the function of guiding the valve shaft body 3. In addition, the annular hole portion 27 formed above the valve shaft insertion hole 28 and connected to the return flow path 23 has a diameter larger than that of the valve shaft insertion hole 28 and has the function of accommodating the spiral spring 4.

[0038] The valve shaft body 3, which is a separate elongated rod-shaped metal component, is arranged along the axis L and penetrates through the valve chamber VC, the valve shaft insertion hole 28, the annular hole portion 27, and the return flow path 23. A conical valve core portion 3a that tapers downward is formed at the lower end of the valve shaft body 3. As Figure 2 shown, when the valve core portion 3a seats on the valve seat 20 of the valve body 2, the flow of the refrigerant in the hole path 21b is restricted. This state is referred to as the non-communication state. However, even when the valve shaft body 3 seats on the valve seat 20, a limited amount of refrigerant still flows. On the other hand, as Figure 3 shown, when the valve core portion 3a moves away from the valve seat 20, the flow of the refrigerant through the hole path 21b increases. This state is referred to as the communication state.

[0039] The valve shaft body 3 has a circumferential groove 3b in the annular hole portion 27. A plate-shaped member (referred to as a stop ring) 41 that is C-shaped when viewed from the direction of the axis L is fitted in the circumferential groove 3b. The spiral spring 4 disposed between the stop ring 41 and the bottom wall of the annular hole portion 27 applies an upward force to the valve shaft body 3 via the stop ring 41.

[0040] (Structure of the motor unit)

[0041] Next, with reference to Figures 2 - 4 , the motor unit 100 will be described. The motor unit 100 is composed of the following components: a toped cylindrical shell 50 fixed to the valve body 2 via a cylindrical cage 11, a stator 55 externally inserted into the shell 50, a rotor 57 equipped inside the shell 50, a substantially toped cylindrical cover 9 covering the periphery of the stator 55, a gear-type reduction mechanism 6 that decelerates and transmits the rotational speed of the rotor 57, and a threaded drive member (also referred to as a drive member) 58 that converts the rotational movement of the output gear of the reduction mechanism 6 into a linear movement via a threaded feed mechanism 54 ( Figure 4 ). In addition, the shell is also referred to as a component having a cylindrical portion installed in such a way that the inside is closed on the valve body side of the electric valve (the shell 50 has a bottomed cylindrical portion). The shell 50 accommodates the rotor 57, the reduction mechanism 6, and the threaded feed mechanism 54, etc. More precisely, a part of the threaded feed mechanism 54 is accommodated in the shell 50, and the whole of the threaded feed mechanism 54 is accommodated in the connection body of the shell 50 and the cage 11.

[0042] The stepping motor 5 has a rotor 57 which is rotatably arranged inside a housing 50 relative to the housing 50, and a rotor support member 56 is fixed to the inner side of the upper part. The stepping motor 5 consists only of the rotor 57 and does not include a stator 55. The stator 55 composed of a yoke 51, a bobbin 52, a coil 53, etc. is fitted and fixed to the outside of the housing 50 and is covered by a resinous 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 terminals T connected to a stepping motor drive circuit board (not shown) are arranged inside it.

[0043] The cage 11 is continuously formed by a cylindrical main body 11a and a flange portion 11b extending radially outward from the upper end of the main body 11a and joined to the lower end of the housing 50. An external thread 11c is formed on the outer periphery of the lower part of the main body 11a. By screwing the external thread 11c into an internal thread 2b formed on the inner periphery of a recess 2a in the valve body 2, the housing 50 is fixed to the valve body 2 via the cage 11. An O-ring OR1 seals between the main body 11a and the recess 2a.

[0044] A threaded bearing member 13 is fitted into the upper inner periphery of the cage 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 parallel to the axis L from its lower end and opening to the outside periphery. The communication hole 13b has a function of introducing the refrigerant flowing into the lower part of the threaded bearing member 13 from the return flow path 23 via the recess 2a into the housing 50. A thin-walled cylindrical body 66 is fixed to the outer periphery of the upper end of the threaded bearing member 13. In addition, 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.

[0045] In Figure 4 it, the reduction mechanism 6 has, on the inner peripheral side of the rotor 57: a sun gear 61 integrally formed with the rotor support member 56; a fixed ring gear 62 fixed to the valve body 2 via the thin-walled cylindrical body 66; planet gears 63 arranged between the sun gear 61 and the fixed ring gear 62 and meshing with them respectively; a planet gear carrier 64 supporting the planet gears 63 to be rotatable; and a bottomed cylindrical output gear member 65 having teeth meshing with the planet gears 63 on its inner periphery. These constitute a differential 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.

[0046] The shaft member 8 passes through the rotor support member 56 and the sun gear 61 and holds them to be rotatable. The upper end of the shaft member 8 is supported by a support member 81 arranged inside the top of the housing 50.

[0047] 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 the output shaft portion 29.

[0048] An internal thread portion 13c formed at the lower part of the through hole 13a of the threaded bearing member 13 is screwed with an external thread portion 58a formed at the lower part of the threaded drive member 58. The rotational movement of the output gear member 65 (the decelerated rotational movement of the rotor 57) is converted into a linear movement along the axis L by a screw feed mechanism (conversion mechanism) 54 constituted by the external thread portion 58a and the internal thread portion 13c.

[0049] 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 threaded drive member 58. The slit 29a and the blade 58b are slidably engaged with each other. Thus, the output shaft portion 29 and the threaded drive member 58 can be integrally rotatably connected. When the output gear member 65 (rotor 57) rotates, the output shaft portion 29 and the threaded drive member 58 rotate integrally, but can linearly move relative to each other along the axis L.

[0050] A metal ball 15 is coaxially welded to the lower end of the threaded drive member 58. On the other hand, a circular hole 3c is formed at the upper end of the valve shaft body 3, and a metal ball receiving seat 16 is press-fitted into the circular hole 3c. A spherical curved surface (specifically, a shape formed by combining a cone and a spherical surface) is formed on the enlarged upper end surface 16a of the ball receiving seat 16, and the ball 15 is held so as to be slidable.

[0051] (Assembly of the electric valve)

[0052] The assembly process of the electric valve 1 will be described. First, the stop ring 41 is assembled to the valve shaft body 3. In addition, in a state where the rotor 57, the reduction mechanism 6, etc. are assembled inside the housing 50, a rotor assembly in which the cage 11 is fixed to the lower end of the housing 50 is prepared.

[0053] The spiral spring 4 is inserted into the annular hole portion 27 of the valve body 2 that has been machined from above, and then the valve shaft body 3 is inserted into the valve shaft insertion hole 28 from above through the concave portion 2a and the inside of the spiral spring 4. At this time, the upper end of the spiral spring 4 abuts against the lower surface of the stop ring 41.

[0054] Thereafter, an O-ring OR1 is disposed in the inner circumferential groove of the recess 2a, and an O-ring OR2 is disposed at the open end of the recess 2a. The external thread 11c of the cage 11 is screwed with the internal thread 2b of the recess 2a of the valve body 2, and the rotor assembly is mounted on the valve body 2. At this time, the O-ring OR1 functions as a sealing mechanism between the main body 11a of the cage 11 and the recess 2a. The flange portion 11b prevents the O-ring OR2 from falling off. In addition, the O-ring OR2 can be disposed on the cage 11 before screwing the cage 11 and the valve body 2, or can be inserted from the upper part of the housing and assembled after screwing the cage 11 and the valve body 2.

[0055] From this state, the cover 9 and the stator 55 are brought close to the housing 50 together from above the housing 50 and cover the housing 50. Since the lower end of the cover 9 is located on the upper surface side of the valve body 2, the O-ring OR2 is disposed between the cover 9 and the cage 11 to seal between the two. A plate-shaped brace 18 is disposed across between the lower end of the cover 9 and the side surface of the valve body 2, and the two are fixed by a screw SC. If the connector portion 9a of the cover 9 is connected to a connector (not shown), an external control device is connected to the circuit board of the electric valve 1 via the terminal T so as to be able to transmit signals.

[0056] (Operation of the electric valve)

[0057] When the rotor 57 of the stepping motor 5 is rotationally driven in one direction by supplying a valve closing control signal of a specified number of pulses from an external control device to the stator 55, the rotational speed is input from the sun gear 61 to the speed reduction mechanism 6, and the rotational speed reduced by the speed reduction mechanism 6 is transmitted to the screw drive member 58 via the output shaft portion 29. When the screw drive member 58 rotates in one direction, the internal thread portion 13c and the external thread portion 58a relatively move in a screw manner, and according to the rotational speed, the screw drive member 58 moves downward in the direction of the axis L.

[0058] When the screw drive member 58 and the ball 15 rotate and descend together, rotational sliding is generated between the ball 15 and the upper end surface 16a of the ball receiving seat 16, and the valve shaft body 3 is downwardly biased via the ball receiving seat 16. The valve shaft body 3 descends against the acting force of the helical spring 4, and the valve element portion 3a seats on the valve seat 20 to be in a valve closed state. As a result, the refrigerant introduced into the first flow path 21 from a condenser (not shown) cannot enter the valve chamber VC from the hole 21b, and the flow of the refrigerant between the first flow path 21 and the second flow path 22 is interrupted.

[0059] On the other hand, when the rotor 57 of the stepping motor 5 is rotationally driven in the other direction by supplying an open valve control signal to the stator 55 through a control device (not shown), the threaded 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 applies a downward force to the valve shaft body 3 disappears, and thus the valve shaft body 3 rises by the action of the helical spring 4. When the valve shaft body 3 rises, the valve core portion 3a separates from the valve seat 20 and becomes an open valve state. Thereby, the refrigerant enters the valve chamber VC from the first flow path 21 via the first connection path 21a and the hole path 21b, and then the refrigerant flows out of the electric valve 1 via the second connection path 22a and the second flow path 22. For example, an open valve control signal for supplying power to the stator 55 is determined based on a signal from a temperature sensor installed in the outlet side pipe of the evaporator, and thereby the amount of refrigerant passing through the hole path 21b during the opening and closing valve operation and during valve opening is controlled.

[0060] The refrigerant discharged from the second flow path 22 enters the return flow path 23 of the electric valve 1 in a lower pressure state when passing through an evaporator (not shown), and then reaches a compressor (not shown) when flowing out of the electric valve 1, and is pressurized as needed and supplied to the condenser.

[0061] According to the present embodiment, in the so-called positive flow in which the hole path 21b side is at a high pressure and the valve chamber VC side is at a low pressure across the valve seat 20, the pressure in the valve opening direction always acts on the valve core portion 3a. However, since a reduction mechanism 6 having a high reduction ratio is disposed between the stepping motor 5 and the valve shaft body 3, the position control of the valve core portion 3a can be reliably performed regardless of the pressure applied to the valve core portion 3a, whether during valve closing or valve opening. However, the electric valve 1 of the present embodiment can also be used in the case of the so-called reverse flow in which the hole path 21b side is at a low pressure and the valve chamber VC side is at a high pressure across the valve seat 20. In this case, the refrigerant from the condenser is introduced into the second flow path 22, and the refrigerant flows out from the first flow path 21 toward the evaporator.

[0062] In addition, the housing 50 is disposed on the side opposite to the valve seat 20 across the return flow path 23, and the low-pressure refrigerant is supplied from the adjacent return flow path 23 to the inside of the housing 50 via the concave portion 2a and the communication hole 13b. Therefore, in addition to using the supplied refrigerant for lubricating the reduction mechanism 6, the wall thickness of the housing 50 can be made thinner, the strength of each threaded portion can be more suppressed, and O-rings OR1 and OR2 with lower pressure resistance can be used. By these, it is possible to contribute to miniaturization, weight reduction, and cost reduction of the electric valve 1.

[0063] Moreover, according to the present embodiment, the shape of the valve body 2 is substantially the same as that of the valve body of a conventional expansion valve having a power element. Therefore, in a refrigeration cycle that has already been used, the electric valve of the present embodiment can be replaced without major design changes.

[0064] (Second Embodiment)

[0065] Figure 5 is a longitudinal sectional view of the electric valve 1A according to the second embodiment in a closed valve state, Figure 6 is a longitudinal sectional view of the electric valve 1A in an open valve state. In this embodiment, it is different from the above-described embodiment in that the structures of the valve body 2A and the valve shaft body 3A are changed and the guide member 12A and the core adjustment member 19A are added. Other structures are the same, so the same reference numerals are used and repeated descriptions are omitted.

[0066] The valve body 2A is different only in that the lower hole portion 27Aa and the upper hole portion 27Ab having a diameter larger than that of the lower hole portion 27Aa are provided in the annular hole portion 27A. Other structures are the same, so repeated descriptions are omitted.

[0067] The coil spring 4 is disposed in the lower hole portion 27Aa, and the core adjustment member 19A is disposed in the upper hole portion 27Ab.

[0068] Figure 7 is a perspective view of the core adjustment member 19A. The core adjustment member 19A is formed, for example, by stamping a metal plate. Specifically, a long and narrow plate is rolled into a cylindrical shape, and both ends are overlapped to form a peripheral wall 19Aa. In addition, a plurality of portions (here, three places) of the peripheral wall 19Aa are cut up along the circumferential direction to form rectangular tongue pieces 19Ab, which are bent radially inward with one end connected to the peripheral wall 19Aa as a starting point. Hemispherical convex portions 19Ac protruding toward the center of the peripheral wall 19Aa are formed near the top ends of the respective tongue pieces 19Ab. Thus, the core adjustment member 19A is formed.

[0069] The outer diameter of the peripheral wall 19Aa in the free state is larger than the inner diameter of the upper hole portion 27Ab. Therefore, when inserted into the upper hole portion 27Ab, the peripheral wall 19Aa is elastically deformed and reduced in diameter, and the outer periphery of the peripheral wall 19Aa is pressed against the inner periphery of the upper hole portion 27Ab by its elastic force, and the core adjustment member 19A is mounted in the upper hole portion 27Ab by the frictional force generated thereby. In addition, as a measure against the core adjustment member 19A coming off, processing such as riveting may be added to the upper end of the upper hole portion 27Ab.

[0070] As shown in Figure 5 、 6 a cylindrical guide member 12A is disposed inside the cage 11. The guide member 12A is coaxially and continuously provided with an upper cylindrical portion 12Aa and a lower cylindrical portion 12Ab having a diameter smaller than that of the upper cylindrical portion 12Aa. The lower cylindrical portion 12Ab is fitted into the bottom wall opening of the concave portion 2a of the valve body 2A by press-fitting. In addition, the guide member 12A has a cylindrical through-hole 12Ac penetrating vertically.

[0071] The valve shaft body 3A is composed of a lower shaft 31A as the first shaft and an upper shaft 32A as the second shaft. The lower shaft 31A, which is a slender rod-shaped metal member, is arranged along the axis L and penetrates through the valve chamber VC of the valve body 2A, the valve shaft insertion hole 28, and the lower hole portion 27Aa.

[0072] At the lower end of the lower shaft 31A, a conical valve core portion 31Aa that tapers downward is formed. In addition, a circumferential groove 31Ab for engaging the stop ring 41 is formed on the outer periphery of the lower shaft 31A, and a conical receiving seat 31Ac that tapers downward is formed at the upper end of the lower shaft 31A.

[0073] The upper shaft 32A is continuously provided with a small-diameter portion 32Aa disposed in the upper hole portion 27Ab and a large-diameter portion 32Ab disposed in the return flow path 23 and the recess 2a and having a diameter larger than that of the small-diameter portion 32Aa. The lower end of the small-diameter portion 32Aa is spherical. In addition, the large-diameter portion 32Ab is slidably fitted into the through hole 12Ac of the guide member 12A. A substantially spherical ball receiving seat 16 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 receiving seat 16 is higher than that of the upper shaft 32A and the lower shaft 31A.

[0074] The ball 15 is brought into contact with the ball receiving seat 16, and the threaded drive member 58 and the upper shaft 32A are connected (brought into contact) along the axis L in a manner capable of transmitting the driving force. In addition, the lower end of the small-diameter portion 32Aa is brought into contact with the conical receiving seat 31Ac, and the upper shaft 32A and the lower shaft 31A are connected (brought into contact) along the axis L in a manner capable of transmitting the driving force. By bringing the hemispherical lower end of the small-diameter portion 32Aa into contact with the conical receiving seat 31Ac, the coaxiality of the upper shaft 32A and the lower shaft 31A can be ensured.

[0075] The contact surface diameter A between the ball receiving 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 receiving seat 31Ac (A < B).

[0076] In the assembly process of the electric valve 1A, first, the stop ring 41 is installed on the lower shaft 31A, and in the same manner as the above-described embodiment, a rotor assembly in which the cage 11 is fixed to the lower end of the housing 50 in a state where the rotor 57, the reduction mechanism 6, etc. are installed inside the housing 50 is prepared.

[0077] The spiral spring 4 is inserted into the lower hole portion 27Aa of the valve body 2A that has been machined from above, and then, from above, the lower shaft 31A is inserted through the recess 2a and the inside of the spiral spring 4 and into the valve shaft insertion hole 28. At this time, the upper end of the spiral spring 4 abuts against the lower surface of the stop ring 41.

[0078] After that, the centering member 19A is inserted into the upper hole portion 27Ab, and the guide member 12A is press-fitted and assembled to the bottom wall opening of the recess 2a. Further, the upper shaft 32A approaches from above the guide member 12A, passes through the through hole 12Ac, inserts the small-diameter portion 32Aa into the centering member 19A, and abuts its lower end against the conical receiving seat 31Ac of the lower shaft 31A. At this time, the three tongues 19Ab of the centering member 19A are elastically deformed, and the convex portion 19Ac abuts against the outer periphery of the small-diameter portion 32Aa, so as to perform a so-called centering function in such a manner that the small-diameter portion 32Aa does not displace relative to the axis L.

[0079] After that, in the same manner as in the first embodiment, the electric valve 1A is completed by assembling the rotor assembly. In addition, the centering member 19A can also be provided in the first embodiment to perform centering of the valve shaft body.

[0080] (Operation of the electric valve)

[0081] When the rotor 57 of the stepping motor 5 is rotationally driven in one direction by supplying a valve closing control signal of a specified number of pulses from an external control device to the stator 55, the rotational speed decelerated by the speed reduction mechanism 6 is transmitted to the screw driving member 58 via the output shaft portion 29, so that the screw driving member 58 moves downward in the direction of the axis L.

[0082] The screw driving member 58 and the ball 15 rotate and descend together, and the driving force toward its lower side is transmitted from the upper shaft 32A to the lower shaft 31A, and the valve element portion 31Aa seats on the valve seat 20 to become a valve closed state. At this time, since the contact surface diameter A between the ball receiving 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 receiving seat 31Ac, relative rotation mainly occurs between the main ball receiving seat 16 and the ball 15, and it is difficult to generate relative rotation between the upper shaft 32A and the lower shaft 31A. Therefore, it is possible to suppress eccentricity (core misalignment) relative to the axis L caused by the swing of the lower shaft 31A, and thereby improve the close contact between the valve element portion 31Aa and the valve seat 20. In addition, since the ball receiving seat 16 and the ball 15 are formed of a material with a relatively high hardness, wear can be suppressed even if relative sliding occurs.

[0083] On the other hand, when a valve opening control signal is supplied from a control device (not shown) to the stator 55 to rotationally drive 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 reduction mechanism 6 and the screw feed mechanism 54. As a result, since the driving force that applies a downward force to the upper shaft 32A disappears, the lower shaft 31A rises according to the acting force of the coil spring 4, and the valve element portion 31Aa moves away from the valve seat 20 to become a valve open state.

[0084] (Modification example)

[0085] Figure 8is a longitudinal sectional view of the cage 11B according to the modified example, Figure 9 and is a top view of the cage 11B. The cage 11B of this modified example can be used in place of the cage 11 and the guide member 12A of the second embodiment.

[0086] The cage 11B as a restricting member is continuously formed by a cylindrical main body 11Ba, a flange portion 11Bb, and a bottom wall 11Bd. The flange portion 11Bb extends radially outward from the upper end of the main body 11Ba and engages with the housing 50, and the bottom wall 11Bd extends radially inward from the upper end of the main body 11Ba. An external thread 11Bc is formed on the outer periphery of the lower part of the main body 11Ba, and an opening 11Be is formed at the center of the bottom wall 11Bd. The cage 11B of this modified example is also fixed to the valve body 2 by screwing the external thread 11Bc with Figure 5 , 6 the internal thread 2b formed on the inner periphery of the recess 2a formed at the upper end of the valve body 2 as shown.

[0087] The inner periphery of the opening 11Be has a shape in which a part of the circumferential direction along the cylindrical surface is directly connected by a plane parallel to the axis L, that is, the opening 11Be has a D shape (non-cylindrical shape) when viewed from the axis L direction. The outer periphery of the large-diameter portion 32Ab of the upper shaft 32A used in this modified example is also not a complete cylindrical shape, but has a D shape (corresponding non-cylindrical shape) when viewed from the axis L direction corresponding to the opening 11Be. As the non-cylindrical shape, it is not limited to the above. For example, it may be a shape in which a part of the circumferential direction along the cylindrical surface is directly connected by two planes parallel to the axis L. Here, a rotation restricting mechanism is constituted by the cage 11B and the upper shaft 32A.

[0088] When the upper shaft 32A is inserted into the opening 11Be of the cage 11B, the upper shaft 32A is guided by the opening 11Be and displaced along the axis L direction, but cannot rotate around the axis L. Therefore, even if the screw driving member 58 rotates, the rotation of the upper shaft 32A can be blocked (restricted), thereby preventing the core misalignment of the upper shaft 32A and also suppressing the core misalignment of the lower shaft 31A.

[0089] In addition, by making the through hole 12Ac of the guide member 12A in the second embodiment the same non-cylindrical shape, the guide member 12A can also be used as a restricting member. In this case, by making the large-diameter portion 32Ab of the upper shaft 32A the same non-cylindrical shape, a rotation restricting mechanism can be similarly constituted, thereby suppressing the core misalignment of the upper shaft 32A during the opening and closing valve operation. Thus, the rotation restricting mechanism constituted by the guide member and the cage into which the non-cylindrical valve shaft body is fitted can also be used in the first embodiment.

[0090] (Third Embodiment)

[0091] Figure 10 is a longitudinal sectional view of the electric valve 1C according to the third embodiment in a closed valve state. In the present embodiment, compared with the first embodiment, it is different in that the structures of the valve body 2C, the valve shaft body 3C, and the cage 11C are changed and the centering member 19A is added. The other structures are the same, so the same reference numerals are used and repeated descriptions are omitted.

[0092] The valve body 2C is different only in that the annular hole portion 27C is shortened in the axial direction and the centering member 19A is disposed inside thereof instead of the helical spring 4. The other structures are the same as those in the first embodiment, so repeated descriptions are omitted. The centering member 19A is the same as that used in the second embodiment.

[0093] The valve shaft body 3C is different only in that the circumferential groove 3Cb is formed to be offset above the return flow path 23. The other structures are the same as those in the first embodiment, so repeated descriptions are omitted.

[0094] The cage 11C is continuously provided with a cylindrical main body 11Ca, a flange portion 11Cb, and a bottomed cylindrical holding portion 11Cd. The flange portion 11Cb extends radially outward from the upper end of the main body 11Ca and engages with the lower end of the housing 50, and the holding portion 11Cd engages with the lower end of the main body 11Ca. An external thread 11Cc is formed on the outer circumference of the lower portion of the main body 11Ca. The structures other than the holding portion 11Cd of the cage 11C are the same as those in the first embodiment, so repeated descriptions are omitted.

[0095] The bottom wall of the holding portion 11Cd has a through hole 11Ce at the center thereof into which the valve shaft body 3C is slidably fitted. A stop ring 41 is engaged with the circumferential groove 3Cb of the valve shaft body 3C formed on the radially inner side of the main body portion 11Ca. The helical spring (also simply referred to as a spring) 4 is disposed around the valve shaft body 3C in a compressed state between the stop ring 41 and the bottom wall of the holding portion 11Cd, thereby applying a force to the valve shaft body 3C in the closing valve direction.

[0096] In the electric valve 1C of the present embodiment, instead of forming a housing portion for the helical spring 4 in the valve body 2C, a holding portion 11Cd is provided as a housing portion for the helical spring 4 in a part of the cage 11C. According to this structure, the valve shaft body 3C, the valve body 2C, and the motor unit 100 (except for the stator unit) can be treated as separate modules. Therefore, the above separate modules can be pre-assembled and assembled to the valve body 2C in one process, thereby improving the assemblability.

[0097] In addition, the present invention is not limited to the above-described embodiments. Within the scope of the present invention, any component of the above-described embodiments can be modified. Additionally, in the above-described embodiments, any component can be added or omitted. For example, an example of using a planetary gear mechanism as a speed reduction mechanism is shown, but it is not limited thereto, and a structure using a gear pair may also be used. Further, in the present embodiment, the axis of the valve shaft body intersects the axis of the return flow path, but the axis of the valve shaft body may not intersect the axis of the return flow path, or the valve shaft body may not intersect the return flow path itself.

[0098] This specification includes the inventions disclosed below.

[0099] (First aspect)

[0100] An electric valve includes:

[0101] A valve body having 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;

[0102] A valve shaft body having a valve element portion that can be seated on the valve seat;

[0103] A motor disposed on the valve body on the opposite side of the valve seat across the third flow path; and

[0104] A conversion mechanism that converts the rotation of the rotor of the motor into linear movement and transmits it to the valve shaft body.

[0105] (Second aspect)

[0106] In the electric valve of the first aspect,

[0107] It has: the rotor of the motor; a speed reduction mechanism that reduces the rotation of the rotor of the motor; the conversion mechanism that converts the rotation reduced by the speed reduction mechanism into linear movement; and a housing that at least houses the speed reduction mechanism,

[0108] The interior of the housing communicates with the third flow path.

[0109] (Third aspect)

[0110] In the electric valve of the first aspect or the second aspect,

[0111] A drive member and a ball receiving seat are disposed between the conversion mechanism and the valve shaft body. The drive member is displaced in the axial direction while rotating, and the ball receiving seat is fixed to the valve shaft body and has a spherical end.

[0112] The ball fixed to the driving component abuts against the end of the ball receiving seat, so that the axial displacement of the driving component is transmitted to the valve shaft body.

[0113] (Fourth mode)

[0114] In the electric valve of the third mode,

[0115] It has a rotation limiting mechanism that restricts the rotation of the valve shaft body relative to the valve body.

[0116] (Fifth mode)

[0117] In the electric valve of the fourth mode,

[0118] The rotation limiting mechanism is composed of a limiting component and the valve shaft body with a non-cylindrical shape. The limiting component is fixed to the valve body and has a non-cylindrical opening, and the valve shaft body engages with the opening.

[0119] (Sixth mode)

[0120] In any one of the electric valves of the first mode to the fifth mode,

[0121] The valve shaft body is composed of a first shaft and a second shaft. The first shaft has the valve core portion seated on the valve seat, and the second shaft is connected to the first shaft and has the ball receiving seat.

[0122] The hardness of the material of the ball receiving seat is greater than the hardness of the materials of the first shaft and the second shaft.

[0123] (Seventh mode)

[0124] In the electric valve of the sixth mode

[0125] The end of the first shaft has a conical shape, the end of the second shaft has a spherical shape, and the conical end abuts against the spherical end.

[0126] The diameter of the contact surface between the ball and the ball receiving seat is smaller than the diameter of the contact surface between the conical end and the spherical end.

[0127] (Eighth mode)

[0128] In any one of the electric valves of the first mode to the fifth mode,

[0129] The valve shaft body is composed of a single rod-shaped component.

[0130] It has a centering component that is installed on the valve body and abuts against the outer periphery of the valve shaft body at multiple positions along the circumferential direction to apply the elastic force to the outer periphery of the valve shaft body.

[0131] (Ninth Mode)

[0132] In any of the electric valves of the first mode to the eighth mode,

[0133] a cylindrical cage is provided, and the cage fixes a threaded bearing member having an internal thread constituting the switching mechanism to the valve body.

[0134] The cage has a holding portion that holds a spring that biases the valve shaft body in the valve closing direction.

[0135] (Tenth Mode)

[0136] In any of the electric valves of the first mode to the ninth mode,

[0137] the electric valve is used for a refrigeration cycle,

[0138] the refrigerant from the condenser is introduced into the first flow path, the refrigerant flows out from the second flow path toward the evaporator, and the refrigerant from the evaporator passes through the third flow path.

[0139] Symbol Explanation

[0140] 1, 1A: Electric valve

[0141] 2, 2A: Valve body

[0142] 3, 3A: Valve shaft body

[0143] 3a, 31Aa: Valve core portion

[0144] 4: Helical spring

[0145] 5: Stepper motor

[0146] 6: Reduction mechanism

[0147] 20: Valve seat

[0148] 21: First flow path

[0149] 22: Second flow path

[0150] 23: Return flow path (third flow path)

[0151] 27: Annular hole portion

[0152] 31A: Lower shaft

[0153] 32A: Upper shaft

[0154] 50: Housing

[0155] 55: Stator

[0156] 57: Rotor

[0157] 100: Motor unit

[0158] VC: Valve chamber

Claims

1. An electric valve, characterized in that: have: 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 shaft body, the valve shaft body having a valve core portion, the valve core portion being seatable on the valve seat; an electric motor disposed on the valve body on the opposite side of the valve seat across the third flow path; and A conversion mechanism converts the rotation of the rotor of the electric motor into a linear motion and transmits the linear motion to the valve shaft body.

2. The electric valve according to claim 1, characterized in that: The invention has: a rotor of the motor; a speed reduction mechanism for reducing the rotation speed of the rotor of the motor; a conversion mechanism for converting the rotation reduced by the speed reduction mechanism into a linear movement; and a housing for accommodating at least the speed reduction mechanism. The interior of the housing communicates with the third flow path.

3. The electric valve according to claim 1, characterized in that: A driving member and a ball socket are arranged between the conversion mechanism and the valve shaft body. The driving member is displaced in the axial direction while rotating. The ball socket is fixed to the valve shaft body and has a spherical end. The ball fixed to the driving member abuts against the end of the ball receiving seat, so that the axial displacement of the driving member is transmitted to the valve shaft body.

4. The electric valve according to claim 3, characterized in that: A rotation restricting mechanism is provided, which restricts the rotation of the valve shaft body relative to the valve body.

5. The electric valve according to claim 4, characterized in that: The rotation restricting mechanism is composed of a restricting member and the non-cylindrical valve shaft body. The restricting member is fixed to the valve body and has a non-cylindrical opening. The valve shaft body engages with the opening.

6. The electric valve according to claim 3, characterized in that: The valve shaft body is composed of a first shaft and a second shaft, the first shaft having the valve core portion seated on the valve seat, and the second shaft connected to the first shaft and having the ball receiving seat. The hardness of the material of the ball socket is greater than the hardness of the material of the first shaft and the second shaft.

7. The electric valve according to claim 6, characterized in that: The end of the first shaft has a conical shape, the end of the second shaft has a spherical shape, and the conical end abuts against the spherical end. The diameter of the contact surface between the ball and the ball socket is smaller than the diameter of the contact surface between the conical end and the spherical end.

8. The electric valve according to claim 3, characterized in that: The valve shaft body is composed of a single rod-shaped component. An alignment member is provided, which is mounted on the valve body and abuts against the outer periphery of the valve shaft at a plurality of locations along the circumferential direction to apply elastic force to the outer periphery of the valve shaft.

9. The electric valve according to claim 1, characterized in that: A cylindrical retainer is provided, which fixes a threaded bearing member having an internal thread constituting the conversion mechanism relative to the valve body. The retainer includes a retaining portion that retains a spring that urges the valve shaft body in a valve closing direction.

10. The electric valve according to claim 1, characterized in that: The electric valve is used in a refrigeration cycle. The refrigerant from the condenser is introduced into the first flow path, the refrigerant flows out from the second flow path toward the evaporator, and the refrigerant from the evaporator passes through the third flow path.

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