Electric valve

Abstract

Provided is an electrically actuated valve capable of improving temperature control efficiency by suppressing recirculation of a refrigerant while ensuring reduction in size and weight.　This electric valve has: a valve body including a first flow passage via which a refrigerant is introduced, a second flow passage via which a refrigerant flows out, a third flow passage through which a refrigerant passes, and a valve seat formed between the first flow passage and the second flow passage; a valve shaft unit including a valve body part that can land on the valve seat; a motor disposed in the valve body; and a conversion mechanism that converts rotation of a rotor of the motor to linear motion and transmits the linear motion to the valve shaft unit. The valve body has an insertion hole through which the second flow passage and the third flow passage are connected, and through which the valve shaft unit is inserted. By positioning a cylindrical sleeve in the insertion hole, communication between the third flow passage and the second flow passage is blocked. The valve shaft unit is disposed inside the sleeve so as to be displaceable in the axial direction.

Description

Electric valve

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

[0002] For example, in the refrigeration cycle of an air conditioner installed in an automobile, a temperature-sensitive thermal expansion valve is used to adjust the amount of refrigerant passing through according to the temperature. Conventionally, such a thermal expansion valve employs a power element that drives the valve element using the pressure of the enclosed working gas.

[0003] Generally, power elements are useful because they have a simple mechanical structure and can sense the refrigerant temperature to control the opening and closing of the expansion valve, but in recent refrigeration cycles, there is a demand for more flexible opening and closing valve control, and for example, there are cases where forced valve closing operation is 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 solenoid valve shuts off the flow of refrigerant passing through the expansion 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 electrically operated valve that is combined with a valve unit and a passage body and that can open and close the valve using a stepping motor in the valve unit. This electrically operated 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 to move the valve element toward or away from the valve seat in the passage body regardless of the temperature of the refrigerant.

[0005] JP 2023-53708 A

[0006] In an electrically operated valve having a valve body with a first flow path through which a refrigerant is introduced, a second flow path through which the refrigerant flows out, a third flow path through which the refrigerant discharged from the second flow path passes, and a valve seat formed between the first flow path and the second flow path, a configuration has been considered in which the valve body portion of the valve stem is seated on the valve seat through the third flow path.

[0007] However, in such an electric valve, since the valve stem is inserted between the third flow path and the second flow path, there is a risk that the refrigerant will flow back from the third flow path to the second flow path, thereby reducing the temperature control efficiency.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electrically operated valve that can suppress refrigerant reflux and improve temperature control efficiency while ensuring compactness and light weight.

[0009] In order to achieve the above object, the motor-operated valve according to the present invention comprises: a valve body having a first flow path through 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 unit having a valve body portion that can seat on the valve seat; a motor disposed in the valve body; and a conversion mechanism that converts rotation of a rotor of the motor into linear movement and transmits it to the valve stem unit, wherein the valve body connects the second flow path and the third flow path and has an insertion hole through which the valve stem unit is inserted, and by disposing a cylindrical sleeve in the insertion hole, communication between the third flow path and the second flow path is blocked, and the valve stem unit is disposed inside the sleeve so as to be displaceable in the axial direction.

[0010] According to the present invention, it is possible to provide an electrically operated valve that can suppress refrigerant reflux and improve temperature control efficiency while ensuring a small size and light weight.

[0011] FIG. 1 is a longitudinal sectional view of a motor-operated valve according to a first embodiment. FIG. 2 is a longitudinal sectional view of a sleeve. FIG. 3 is an enlarged view of part A in FIG. 1. FIG. 4 is a longitudinal sectional view showing the periphery of a motor unit. FIG. 5 is a longitudinal sectional view of a motor-operated valve according to a second embodiment. FIG. 6 is a longitudinal sectional view of a motor-operated valve according to a third embodiment. FIG. 7 is a plan view of the B-B cross section of FIG. 6. FIG. 8 is a longitudinal sectional view of a motor-operated valve according to a fourth embodiment. FIG. 9 is a longitudinal sectional view of a motor-operated valve according to a fifth embodiment.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] (Definition of Direction) In this specification, the direction from the valve seat 20 toward the motor unit 100 is defined as the "upward direction," and the direction from the motor unit 100 toward the valve seat 20 is defined as the "downward direction." The axis of the motor-operated valve 1 is defined as L.

[0014] (First embodiment) Fig. 1 is a longitudinal cross-sectional view of a motor-operated valve 1 in this embodiment, showing the valve in a closed state. Fig. 2 is a longitudinal cross-sectional view of a sleeve. Fig. 3 is an enlarged view of part A in Fig. 1.

[0015] In FIG. 1 , the motor-operated valve 1 includes a valve body 2 , a valve stem unit 3 , a substantially cylindrical sleeve 10 , and a motor unit 100 .

[0016] The valve body 2 includes a first flow path 21, a second flow path 22, a first connecting path 21a, an orifice path 21b, a second connecting path 22a, and a return flow path (third flow path) 23. The first flow path 21 and the first connecting 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 connecting path 21a. The second flow path 22 and the second connecting path 22a extend perpendicular to the axis L on the opposite side of the valve body 2 from the first flow path 21, and the inner diameter of the second flow path 22 is larger than the inner diameter of the second connecting path 22a.

[0017] The orifice passage 21b extends along the axis L, with its lower end communicating with the first connection passage 21a near the tip thereof and its upper end communicating with the second connection passage 22a near the tip thereof. The second connection passage 22a defines a valve chamber VC, and the upper end of the orifice passage 21b defines a valve seat 20. The return passage 23 extends in a direction intersecting the axis L between the motor unit 100 and the second passage 22. A recess 2a is formed at the upper end of the valve body 2, and a cylindrical through-hole 2c formed in the bottom of the recess 2a communicates with the return passage 23. The recess 2a is a recess for mounting a rotor assembly including a motor.

[0018] 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 fluid in the valve chamber VC is discharged via the discharge-side flow path to an evaporator (not shown) outside the motor-operated valve. The return flow path 23 receives refrigerant that has passed through the evaporator.

[0019] 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 unit 3, and functions to guide the stem unit 3. In other words, a gap (passage) large enough to allow sliding is formed between the inner circumferential surface of the stem insertion hole 28 and the outer circumferential surface of the lower stem 31 of the stem unit 3.

[0020] Furthermore, the annular hole (insertion hole) 27 formed above the stem insertion hole 28 and connected to the return flow path 23 has a larger diameter than the stem insertion hole 28 and functions to accommodate the coil spring 4. A fitting portion 27a is formed on the inner periphery of the annular hole 27 intersecting the return flow path 23. The inner diameter of the fitting portion 27a is preferably larger than the inner diameter of the remaining annular hole 27. Furthermore, it is preferable that the inner diameter of the return flow path 23 is narrowed in the vicinity of the through hole 2c and the fitting portion 27a.

[0021] As a result, the second connection passage 22 a and the annular hole 27 communicate with each other via the gap between the valve stem insertion hole 28 and the lower valve stem 31 so that the refrigerant can move therethrough.

[0022] The valve stem unit 3 has a lower valve stem 31 and an upper valve stem 32 arranged along the axis L, and the lower valve stem 31 and the upper valve stem 32 move together in the vertical direction when the motor-operated valve 1 opens or closes. The lower valve stem 31 passes through the valve chamber VC and the valve stem insertion hole 28, and has its upper end located within the annular hole 27. A conical valve body portion 31a whose diameter decreases as it extends downward is formed at the lower end of the lower valve stem 31.

[0023] As shown in Figure 1, when the valve body 31a 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 body 31a is seated on the valve seat 20, a restricted amount of refrigerant may still flow. On the other hand, when the valve body 31a is separated from the valve seat 20, the flow of refrigerant passing through the orifice passage 21b increases. This state is called a communicating state.

[0024] The lower valve shaft 31 has a circumferential groove 31b within the annular hole 27. A C-shaped plate (referred to as a retaining ring) 43 is fitted into the circumferential groove 31b when viewed in the direction of the axis L. A coil spring 4 is arranged between the retaining ring 43 and the bottom wall of the annular hole 27 and biases the lower valve shaft 31 upward via the retaining ring 43.

[0025] The upper valve shaft 32 comprises a large-diameter portion 32a and a small-diameter portion 32b connected together, and a spherical portion formed at the lower end of the small-diameter portion 32b abuts against a tapered surface formed at the upper end of the lower valve shaft 31. Axial alignment can be achieved by abutting the spherical portion against the tapered surface, which tapers downward. The large-diameter portion 32a of the upper valve shaft 32 slidably fits into the inner periphery of the sleeve 10, and the small-diameter portion 32b protrudes from the lower end of the sleeve 10. The sleeve 10 is preferably made of a resin that is resistant to swelling and has low thermal conductivity, such as PPS (polyphenylene sulfide), but may also be made of metal.

[0026] In FIG. 2, the outer periphery of the sleeve 10 is formed with a cylindrical upper large diameter portion 10a, a medium diameter portion 10b having a smaller diameter than the upper large diameter portion 10a, a cylindrical small diameter portion 10c having a smaller diameter than the medium diameter portion 10b, and a cylindrical lower large diameter portion 10d having a larger diameter than the small diameter portion 10c and a smaller diameter than the medium diameter portion 10b.

[0027] As shown in FIG. 3, the medium diameter portion 10b has a first outer circumferential surface 10e whose diameter decreases downward, and a cylindrical second outer circumferential surface 10f connected to the lower end of the first outer circumferential surface 10e.

[0028] 2, the inner periphery of the sleeve 10 is formed with a cylindrical first inner circumferential surface 10g and a cylindrical second inner circumferential surface 10h connected to the lower end of the first inner circumferential surface 10g. The first inner circumferential surface 10g and the upper valve shaft 32 are slidably fitted together. In other words, a gap (passage) large enough to allow sliding is formed between the first inner circumferential surface 10g and the outer circumferential surface of the upper valve shaft 32. This gap allows communication between the annular hole 27 and the interior of the holder 11 so that the refrigerant can move.

[0029] (Configuration of Motor Unit) Figure 4 is a vertical cross-sectional view showing the periphery of the motor unit 100. The motor unit 100 will be described with reference to Figure 4. The motor unit 100 is composed of a cylindrical can 50 with a top that is fixed to the valve body 2 via a cylindrical holder 11, a stator 55 that is fitted onto the can 50, a rotor 57 that is 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 before transmitting it, a screw 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 linear movement via a screw feed mechanism 54 and transmits the linear movement to the valve stem unit 3, and a ball 15 welded to the lower end of the screw drive member.

[0030] The can 50 is a member having a cylindrical portion (the can 50 has a cylindrical portion with a bottom) that is attached to the valve body 2 side of the motor-operated valve 1 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.

[0031] The stepping motor 5 is disposed inside the can 50 and is rotatable relative to the can 50, and has a rotor 57 with a rotor support member 56 fixed to the upper inside of the rotor 57. Here, the stepping motor 5 consists only of the rotor 57 and does not include the 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 drive circuit board (not shown) is disposed inside the connector portion 9a.

[0032] 1, 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 can 50 is fixed to the valve main body 2 via the holder 11 by threading the male thread 11c into a female thread 2b that is formed on the inner periphery of a recess 2a in the valve main body 2. An O-ring OR1 seals the gap between the main body 11a and the recess 2a. Therefore, the inside of the connected body of the can 50 and the holder 11 can communicate with the outside of the connected body only via the through-hole 2c in the valve main body 2.

[0033] The threaded bearing member 13 is press-fitted onto the inner periphery of the upper part of the holder 11. 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 threaded bearing member 13 parallel to the axis L and opening at the outer periphery. The communication hole 13b serves to introduce the refrigerant that flows below the threaded bearing member 13 via the through hole 2c 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 29 is rotatably fitted into the upper part of the through hole 13a of the threaded bearing member 13.

[0034] 4, the reduction mechanism 6 comprises 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, planetary gears 63 arranged between the sun gear 61 and the fixed ring gear 62 and meshing with them, a carrier 64 that rotatably supports the planetary gears 63, and a cylindrical output gear member 65 with a bottom and teeth on its inner periphery that mesh with the planetary gears 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.

[0035] The shaft member 8 passes through the rotor support member 56 and the sun gear 61 and holds them rotatably, and the upper end of the shaft member 8 is supported by a support member 81 arranged inside the top of the can 50.

[0036] 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.

[0037] A male threaded portion 58a formed on the lower portion of a screw drive member 58 is threadedly engaged with 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 reduced 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.

[0038] A slit 29a is formed at the lower end of the output shaft 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 29 is connected to the screw drive member 58 so as to be rotatable together, and when the output gear member 65 (rotor 57) rotates, the output shaft 29 and the screw drive member 58 rotate together, but are also capable of linear movement relative to each other along the axis L.

[0039] 1, a metal ball 15 is coaxially welded to the lower end of the screw drive member 58. Meanwhile, a circular hole 31c is formed in the upper end of the upper valve stem 32 of the valve stem unit 3, and a metal ball seat 16 is press-fitted into the circular hole 31c. 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.

[0040] (Assembly of the Motor-Operated Valve) The assembly process of the motor-operated valve 1 will be described. First, the retaining ring 43 is attached to the lower valve shaft 31. Then, the rotor 57, the reduction mechanism 6, etc. are attached to the inside of the can 50, and the holder 11 is fixed to the lower end of the can 50 to prepare a rotor assembly.

[0041] The coil spring 4 is inserted from above into the annular hole 27 of the machined valve body 2, and then the lower valve stem 31 is passed from above through the through-hole 2c of the recess 2a and the inside of the coil spring 4 and inserted into the valve stem insertion hole 28. At this time, the upper end of the coil spring 4 abuts against the lower surface of the retaining ring 43.

[0042] Thereafter, the sleeve 10 is passed through the through-hole 2c from the lower end side, the lower large-diameter portion 10d is press-fitted into the fitting portion 27a, and the medium-diameter portion 10b is disposed in the through-hole 2c, and the sleeve 10 is pressed downward into the valve body 2. As a result, as shown in Fig. 3, a so-called wedge effect causes the first outer peripheral surface 10e of the sleeve 10 to bite into the inner peripheral surface of the through-hole 2c, thereby performing press-fitting, and a seal is secured between the sleeve 10 and the through-hole 2c, making it possible to block the inflow of refrigerant from the return flow path 23.

[0043] Furthermore, the press-fitting of the lower large-diameter portion 10d and the fitting portion 27a ensures a seal between the return flow passage 23 and the annular hole 27, thereby blocking the inflow of refrigerant from the return flow passage 23. At this time, the press-fitting of the lower large-diameter portion 10d into the fitting portion 27a compresses the lower large-diameter portion 10d radially inward, thereby reducing the inner diameter of the lower large-diameter portion 10d. According to this embodiment, the second inner circumferential surface 10h, which is larger in diameter than the first inner circumferential surface 10g, is formed at the lower end of the sleeve 10. Therefore, even if the lower large-diameter portion 10d is compressed radially inward, the second inner circumferential surface 10h, which is its inner periphery, does not interfere with the upper valve shaft 32 and does not hinder the sliding of the upper valve shaft 32. To ensure this function, it is preferable that the length from the lower end of the second inner circumferential surface 10h be longer than the press-fit length of the fitting portion 27a of the sleeve 10.

[0044] After the sleeve 10 is attached to the valve body 2 in this manner, the upper valve stem 32 with the ball seat 16 press-fitted into its upper end is inserted into the sleeve 10 until its lower end abuts against the upper end of the lower valve stem 31.

[0045] Thereafter, an O-ring OR1 is placed in the outer circumferential groove of the body 11a of the holder 11, and an O-ring OR2 is placed around the open end of the recess 2a. The holder 11 is then fitted into the recess 2a, and the male thread 11c is threaded into the female thread 2b to attach the rotor assembly to the valve body 2. At this time, the O-ring OR1 provides 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 threaded onto the valve body 2, or it may be inserted from the top of the can after the holder 11 is threaded onto the valve body 2 and assembled.

[0046] When the rotor assembly is attached to the valve body 2 , the ball 15 welded to the lower end of the screw drive member 58 is seated on the upper end of the ball seat 16 .

[0047] From this state, the cover 9 together with the stator 55 is brought close 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 with screws SC. When the connector portion 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 that signals can be transmitted.

[0048] (Operation of the Motor-Operated Valve) When the rotor 57 of the stepping motor 5 is driven to rotate 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 threadably rotate relative to each other, and the screw drive member 58 moves downward in the direction of the axis L according to the rotational speed.

[0049] When the screw drive member 58 rotates and descends together with the ball 15, a rotational slide occurs between the ball 15 and the upper end surface 16a of the ball seat 16, and the valve stem unit 3 is urged downward via the ball seat 16. The valve stem unit 3 descends against the urging force of the coil spring 4, and the valve body 31a seats on the valve seat 20, resulting in a closed valve state. As a result, the refrigerant introduced into the first flow path 21 from a condenser (not shown) cannot enter the valve chest VC through the orifice passage 21b, and the flow of refrigerant is interrupted between the first flow path 21 and the second flow path 22.

[0050] On the other hand, when a control device (not shown) supplies a valve-opening control signal to the stator 55 to rotate the rotor 57 of the stepping motor 5 in the other direction, the screw drive member 58 moves upward in the direction of the axis L via the reduction gear mechanism 6 and the screw feed mechanism 54. As a result, the driving force biasing the valve stem unit 3 downward disappears, and the valve stem unit 3 rises due to the biasing force of the coil spring 4. When the valve stem unit 3 rises, the valve body 31a separates from the valve seat 20, establishing an open valve state. As a result, refrigerant flows from the first flow path 21 into the valve chamber VC via the first connecting path 21a and the orifice path 21b, and then flows out of the motor-operated valve 1 via the second connecting path 22a and the second flow path 22. For example, the valve-opening control signal supplied to the stator 55 is determined in response to a signal from a temperature sensor attached to the outlet piping of the evaporator, thereby controlling the opening and closing of the valve and the amount of refrigerant passing through the orifice path 21b when the valve is open.

[0051] 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.

[0052] According to this embodiment, the annular hole portion 27 communicating with the second connection passage 22a is cut off from communication with the return flow path 23 by the lower large diameter portion 10d of the sleeve 10, so that refrigerant does not flow from the return flow path 23 into the annular hole portion 27, thereby suppressing the return flow of refrigerant and improving the temperature control efficiency of the electric valve.

[0053] Furthermore, according to this embodiment, the second connection passage 22a downstream of the valve seat 20 communicates with the space inside the can 50 via the gap between the first inner circumferential surface 10g of the sleeve 10 and the outer circumferential surface of the upper valve stem 32, the annular hole 27, and the gap between the valve stem insertion hole 28 and the lower valve stem 31. Therefore, liquid refrigerant before heat exchange in the evaporator can be supplied into the can 50 via these gaps and spaces, and the reduction gear mechanism 6 and other components can be lubricated by the oil mixed in the refrigerant.

[0054] Furthermore, according to this embodiment, the valve seat 20 is sandwiched between the orifice passage 21b and the valve chamber VC, resulting in a so-called forward flow, whereby pressure always acts on the valve element 31a in the valve-opening direction. However, because the speed reduction mechanism 6, which has a high reduction ratio, is disposed between the stepping motor 5 and the valve stem unit 3, the position of the valve element 31a can be reliably controlled both when the valve is closed and when the valve is opened, regardless of the pressure applied to the valve element 31a. However, the motor-operated valve 1 of this embodiment can also be used in a so-called reverse flow, whereby pressure is low on the orifice passage 21b and high on the valve chamber VC, whereby refrigerant is introduced from the condenser into the second flow path 22 and flows out of the first flow path 21 toward the evaporator. However, reflux between the return flow path 23 and the second flow path 22 can be similarly suppressed.

[0055] According to this embodiment, 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, so that it is possible to replace the electric valve of this embodiment in refrigeration cycles that are already in use without requiring major design changes.

[0056] 5 is a longitudinal cross-sectional view of a motor-operated valve 1A according to a second embodiment in a closed state. In this embodiment, only the sleeve 10A is different from the above-described embodiment, and the other configurations are the same. Therefore, the same reference numerals are used and redundant description will be omitted.

[0057] The upper large-diameter portion 10Aa of the sleeve 10A has an upper circumferential groove (second circumferential groove) 10Ai, and the lower large-diameter portion 10Ad has a lower circumferential groove (first circumferential groove) 10Aj. An O-ring (sealing member) OR3 is disposed in the upper circumferential groove 10Ai to seal between the upper large-diameter portion 10Aa and the inner periphery of the body 11a of the holder 11, and an O-ring (sealing member) OR4 is disposed in the lower circumferential groove 10Aj to seal between the lower large-diameter portion 10Ad and the inner circumferential surface of the fitting portion 27a. The medium-diameter portion 10Ab and the small-diameter portion 10Ac are simply cylindrical.

[0058] According to this embodiment, there is no need to press-fit the medium diameter portion 10Ab into the through hole 2c, and even if a gap occurs between them, the O-ring OR3 can ensure a seal between the upper large diameter portion 10Aa and the inner surface of the holder 11.

[0059] Furthermore, even if the lower large diameter portion 10Ad is simply inserted into the fitting portion 27a without being press-fitted, the O-ring OR4 can ensure a seal between the lower large diameter portion 10Ad and the fitting portion 27a. As a result, equipment for press-fitting the sleeve 10A is not required when assembling the motor-operated valve 1, which improves ease of manufacture.

[0060] (Third embodiment) Figure 6 is a longitudinal sectional view of a motor-operated valve 1B according to a third embodiment in a valve closed state. Figure 7 is a plan view of the B-B cross section in Figure 6. In this embodiment, only the sleeve 10B is different from the first embodiment, and the other configurations are the same, so the same reference numerals are used and redundant description will be omitted.

[0061] The sleeve 10B has a different inner peripheral surface shape from that of the first embodiment. Specifically, the sleeve 10B has a plurality of (three in this example) axial grooves 10Bk formed on its inner peripheral surface at equal intervals in the circumferential direction across a first inner peripheral surface 10Bg and a second inner peripheral surface 10Bh. While the axial grooves 10Bk have a rectangular cross-sectional shape, they may also have a semicircular cross-sectional shape. The shapes of the outer peripheral surface of the sleeve 10B (upper large diameter portion 10Ba, medium diameter portion 10Bb, small diameter portion 10Bc, and lower large diameter portion 10Bd) are the same as those of the first embodiment.

[0062] According to this embodiment, when the sleeve 10B is assembled to the valve body 2, in addition to the gap between the opposing inner and outer circumferential surfaces, an axial groove 10Bk is formed between the upper valve stem 32 and the first inner circumferential surface 10Bg, as a passage for passing the refrigerant. This allows the amount of refrigerant supplied from the fitting portion 27a to the inside of the can 50 to be increased.

[0063] Instead of forming an axial groove in the sleeve 10B, an axial groove may be formed in the outer peripheral surface of the upper valve shaft 32. Alternatively, instead of an axial groove, a spiral groove through which the refrigerant can pass may be formed in at least one of the inner peripheral surface of the sleeve 10B and the outer peripheral surface of the upper valve shaft 32, or an uneven structure may be formed on at least one of the surfaces to allow the refrigerant to pass through.

[0064] 8 is a longitudinal cross-sectional view of a motor-operated valve 1C according to a fourth embodiment in a valve-closed state. This embodiment differs from the first embodiment only in that a compression coil spring 12 is provided and in the configuration of a sleeve 10C. Since the other configurations are the same as those of the first embodiment, the same reference numerals are used and redundant description will be omitted.

[0065] The sleeve 10C has a different outer peripheral surface shape from that of the first embodiment. More specifically, a flange portion 10Cm protruding radially outward is formed on the upper large diameter portion 10Ca. The sleeve 10C has the same intermediate diameter portion 10Cb, small diameter portion 10Cc, lower large diameter portion 10Cd, and inner peripheral surface as those of the first embodiment.

[0066] A compression coil spring (elastic body) 12 is arranged inside the holder 11 between the flange portion 10Cm and the underside of the screw bearing member 13, and urges the sleeve 10C downward relative to the screw bearing member 13, thereby enhancing the wedge effect acting between the first outer peripheral surface 10e (Figure 4) and the through hole 2c.

[0067] 9 is a longitudinal cross-sectional view of a motor-operated valve 1D according to a fifth embodiment in a closed state. In this embodiment, only a sleeve 10D is different from the first embodiment, and the other configurations are the same. Therefore, the same reference numerals are used and redundant description will be omitted.

[0068] The sleeve 10D has a different outer peripheral surface shape from that of the first embodiment. Specifically, the upper large-diameter portion 10Da of the sleeve 10D is a thin, disk-shaped portion, and its outer diameter is slightly smaller than the inner diameter of the lower end of the recess 2a. The medium-diameter portion 10Db, the small-diameter portion 10Dc, the lower large-diameter portion 10Dd, and the inner peripheral surface of the sleeve 10D are the same as those of the first embodiment.

[0069] When the sleeve 10D is assembled to the valve body 2, the lower surface of the upper large-diameter portion 10Da abuts against the upper surface of the bottom wall of the recess 2a, and the lower end of the main body 11a of the holder 11 abuts against the upper surface of the upper large-diameter portion 10Da along the entire circumference. By threading the male thread 11c into the female thread 2b, the holder 11 is displaced downward, causing the lower end of the main body 11a to press the upper large-diameter portion 10Da against the bottom wall of the recess 2a, thereby attaching the sleeve 10D to the valve body 2. This enhances the wedge effect acting between the first outer peripheral surface 10e (FIG. 4) and the through-hole 2c.

[0070] The present invention is not limited to the above-described embodiments. Any of the components of the above-described embodiments can be modified within the scope of the present invention. Furthermore, any of the components can be added or omitted from the above-described embodiments. For example, although an example has been shown in which a planetary gear mechanism is used as the reduction mechanism, the present invention is not limited to this, and a gear pair can also be used.

[0071] This specification includes the following disclosure of the invention: (First Aspect) An electrically operated valve comprising: a valve body including a first flow path through 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 unit including a valve body portion capable of seating on the valve seat, a motor disposed in the valve body, and a conversion mechanism that converts rotation of a rotor of the motor into linear movement and transmits the linear movement to the valve stem unit, wherein the valve body connects the second flow path and the third flow path and has an insertion hole through which the valve stem unit is inserted, wherein communication between the third flow path and the second flow path is blocked by disposing a cylindrical sleeve in the insertion hole, and wherein the valve stem unit is disposed inside the sleeve so as to be displaceable in the axial direction.

[0072] (Second aspect) The electric valve of the first aspect, characterized in that the valve seat is positioned on the opposite side of the motor across the third flow path, the electric valve has a rotor of the motor, a reduction mechanism that reduces the rotation of the rotor of the motor, the conversion mechanism that converts the rotation reduced by the reduction mechanism into linear movement, and a can that houses at least the reduction mechanism, and the inside of the can is connected to the second flow path through the space between the sleeve and the valve stem unit.

[0073] (Third Aspect) The motor-operated valve of the first or second aspect, characterized in that the valve stem unit is slidable along the inner circumferential surface of the sleeve, and either the inner circumferential surface of the sleeve or the outer circumferential surface of the valve stem unit is provided with grooves or irregularities through which a refrigerant can pass.

[0074] (Fourth Aspect) An electric valve according to any one of the first to third aspects, characterized in that the valve seat is positioned on the opposite side of the motor across the third flow path, one end of the sleeve is press-fitted into the insertion hole, and the other end of the sleeve is press-fitted into a through hole, which connects a recess for mounting the motor to the third flow path.

[0075] (Fifth Aspect) The motor-operated valve of the fourth aspect, characterized in that a tapered surface is formed on the other end side of the sleeve, the diameter of which decreases toward the one end side, and by pressing the sleeve toward the one end side, the tapered surface bites into the inner periphery of the through hole.

[0076] (Sixth Aspect) The motor-operated valve according to the fifth aspect, wherein the inner diameter of one end of the sleeve is larger than the inner diameter of the other end of the sleeve.

[0077] (Seventh aspect) An electric valve according to any one of the first to third aspects, characterized in that the valve seat is arranged on the opposite side of the motor across the third flow path, the sleeve and the insertion hole are sealed by a sealing member arranged in a first circumferential groove formed on one end side of the sleeve, the sleeve and the through hole are sealed by a sealing member arranged in a second circumferential groove formed on the other end side of the sleeve, and the through hole connects a recess for mounting the motor to the third flow path.

[0078] (Eighth Aspect) The motor-operated valve of any of the first to third aspects, characterized in that the valve seat is positioned on the opposite side of the third flow path from the motor, the motor-operated valve having a rotor of the motor, a speed reduction mechanism that reduces the rotation of the motor rotor, the conversion mechanism that converts the rotation reduced by the speed reduction mechanism into linear movement, a can that houses at least the speed reduction mechanism, a holder that fixes the can to the valve body, and an elastic body that is positioned between the holder and the sleeve, and the elastic body urges the sleeve in a direction away from the holder.

[0079] (Aspect 9) The motor-operated valve of aspect 8, characterized in that one end of the sleeve is press-fitted into the insertion hole, and the other end of the sleeve is press-fitted into a through hole, which connects a recess for mounting the motor to the third flow path.

[0080] (10th Aspect) An electric valve according to any one of the first to third aspects, characterized in that the valve seat is positioned on the opposite side of the third flow path from the motor, the electric valve has a 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, a can that houses at least the speed reduction mechanism, and a holder that fixes the can to the valve body, and the sleeve is sandwiched between the holder and the valve body.

[0081] (11th Aspect) The motor-operated valve of the 10th aspect, characterized in that one end of the sleeve is press-fitted into the insertion hole, and the other end of the sleeve is press-fitted into a through hole, and the through hole connects a recess for mounting the motor to the third flow path.

[0082] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D: Motor-operated valve 2: Valve body 3: Valve stem unit 31: Lower valve stem 32: Upper valve stem 31a: Valve body 4: Coil spring 5: Stepping motor 6: Speed ​​reducing mechanism 10: Sleeve 12: Compression coil spring 20: Valve seat 21: First flow path 22: Second flow path 23: Return flow path (third flow path) 27: Annular hole 50: Can 55: Stator 57: Rotor 100: Motor unit VC: Valve chest

Claims

1. An electrically operated valve comprising: a valve body having a first flow path through 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 unit having a valve body portion that can seat on the valve seat; a motor disposed in the valve body; and a conversion mechanism that converts rotation of a rotor of the motor into linear movement and transmits it to the valve stem unit, wherein the valve body connects the second flow path and the third flow path and has an insertion hole through which the valve stem unit is inserted, and by disposing a cylindrical sleeve in the insertion hole, communication between the third flow path and the second flow path is blocked, and the valve stem unit is disposed inside the sleeve so as to be displaceable in the axial direction.

2. The motor-operated valve according to claim 1, characterized in that the valve seat is positioned on the opposite side of the third flow path from the motor, the motor rotor, a reduction mechanism that reduces the rotation of the motor rotor, the conversion mechanism that converts the rotation reduced by the reduction mechanism into linear movement, and a can that houses at least the reduction mechanism, and the inside of the can is connected to the second flow path through the space between the sleeve and the valve stem unit.

3. The motor-operated valve according to claim 2, characterized in that the valve stem unit is slidable along the inner circumferential surface of the sleeve, and either the inner circumferential surface of the sleeve or the outer circumferential surface of the valve stem unit has grooves or irregularities formed thereon that allow the refrigerant to pass through.

4. The motor-operated valve according to claim 1, characterized in that the valve seat is positioned on the opposite side of the third flow path from the motor, one end of the sleeve is press-fitted into the insertion hole, and the other end of the sleeve is press-fitted into a through hole, which connects a recess for mounting the motor to the third flow path.

5. The motor-operated valve according to claim 4, characterized in that a tapered surface is formed on the other end of the sleeve, the diameter of which decreases as it approaches the one end, and by pressing the sleeve towards the one end, the tapered surface bites into the inner periphery of the through hole.

6. The motor-operated valve according to claim 5, wherein the inner diameter of one end of the sleeve is larger than the inner diameter of the other end of the sleeve.

7. The motor-operated valve according to claim 1, characterized in that the valve seat is arranged on the opposite side of the third flow path from the motor, the sleeve and the insertion hole are sealed by a sealing member arranged in a first circumferential groove formed on one end side of the sleeve, the sleeve and the through hole are sealed by a sealing member arranged in a second circumferential groove formed on the other end side of the sleeve, and the through hole connects a recess for mounting the motor to the third flow path.

8. The motor-operated valve according to claim 1, characterized in that the valve seat is positioned on the opposite side of the third flow path to the motor, and the motor-operated valve has a rotor of the motor, a speed reduction mechanism that reduces the rotation of the rotor of the motor, a conversion mechanism that converts the rotation reduced by the speed reduction mechanism into linear movement, a can that houses at least the speed reduction mechanism, a holder that fixes the can to the valve body, and an elastic body that is positioned between the holder and the sleeve, and the elastic body urges the sleeve in a direction away from the holder.

9. The motor-operated valve according to claim 8, characterized in that one end of the sleeve is press-fitted into the insertion hole, and the other end of the sleeve is press-fitted into a through-hole, which connects a recess for mounting the motor to the third flow path.

10. The motor-operated valve according to claim 1, characterized in that the valve seat is positioned on the opposite side of the third flow path from the motor, the motor rotor, a reduction mechanism that reduces the rotation of the motor rotor, the conversion mechanism that converts the rotation reduced by the reduction mechanism into linear movement, a can that houses at least the reduction mechanism, and a holder that fixes the can to the valve body, and the sleeve is sandwiched between the holder and the valve body.

11. The motor-operated valve according to claim 10, characterized in that one end of the sleeve is press-fitted into the insertion hole, and the other end of the sleeve is press-fitted into a through-hole, which connects a recess for mounting the motor to the third flow path.

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