Electric valves and refrigeration cycle systems

Abstract

The present invention provides an electric valve capable of reducing noise and a refrigeration cycle system equipped with the electric valve. [Solution] The electric valve 1 comprises a valve housing 2, a valve body 3, a support member 4, a stepping motor 5, and a guide part 6. A reduction space S1 is formed between the inner circumferential surface 61A of the through hole 61 of the guide part 6 and the outer circumferential surface 31A of the valve body 3, thereby suppressing pressure fluctuations in the valve chamber 2A, making the valve body 3 less prone to vibration, and thus reducing noise.

Description

Technical Field

[0001] The present invention relates to an electric valve and a refrigeration cycle system.

Background Art

[0002] Generally, in an electric valve that adjusts the opening degree of a valve port by moving a valve body forward and backward, means for generating a rotational driving force such as a stepping motor is provided, and a screw feed mechanism for converting rotational motion into linear motion may be provided. As such an electric valve, an electric control valve incorporating a compression spring in a valve holder has been proposed (for example, see Patent Document 1). In the electric control valve described in Patent Document 1, when the valve body seats on the valve seat portion, no spring load is generated, and when the male screw shaft further moves in the valve closing direction, a spring load that presses the valve body against the valve seat portion is generated, thereby avoiding the sliding rotation in the state where the valve body is pressed against the valve seat portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0005] The object of the present invention is to provide an electric valve capable of reducing noise and a refrigeration cycle system equipped with the electric valve. [Means for solving the problem]

[0006] The electric valve of the present invention comprises a valve housing, a valve body that changes the opening degree of a valve port of a valve chamber provided in the valve housing, a rotational driving means for rotating a rotor shaft, a screw feed mechanism that moves the valve body axially forward and backward by converting the rotational motion of the rotor shaft into linear motion, and a guide portion that guides the valve body axially between the valve port and the screw feed mechanism, wherein, from the fully open state to the fully closed state of the valve body, at least one reduction space is formed between the inner circumferential surface of the through hole of the guide portion and the outer circumferential surface of the valve body, which is closed by both the inner circumferential surface and the outer circumferential surface and closed from both sides in the axial direction.

[0007] According to the present invention as described above, a deceleration space is formed between the inner circumferential surface of the through-hole of the guide portion and the outer circumferential surface of the valve body. As the fluid that passes through the valve port and flows toward the screw feeding mechanism flows into the deceleration space as it passes between the inner circumferential surface of the through-hole of the guide portion and the outer circumferential surface of the valve body, the fluid is decelerated in the deceleration space, and pressure fluctuations in the valve chamber are suppressed, making the valve body less prone to vibration and thus reducing noise.

[0008] Furthermore, "valve body" refers to the part connected to the rotor shaft and moving axially, specifically the part on the valve port side of the screw feed mechanism. For example, if a valve body member is provided that includes a part that can contact the valve port (such as a needle valve) and a member that does not transmit the rotation of the rotor shaft to the valve body member, both of these are included in the valve body. Also, the deceleration space formed in the fully open state of the valve body and the deceleration space formed in the fully closed state do not have to coincide; for example, the deceleration space formed in the fully open state may be open in the fully closed state. In addition, "closure" in this invention means that the clearance necessary for the guide part to guide the valve body is permitted, and that the deceleration space is not in communication with other spaces other than such clearance.

[0009] In this case, in the electric valve of the present invention, the deceleration space is preferably formed by a space-forming portion provided on one of the inner circumferential surface and the outer circumferential surface, and the space-forming portion preferably has a separation portion separated from the other of the inner circumferential surface and contact portions provided on both sides in the axial direction relative to the separation portion and capable of contacting the other. With such a configuration, the volume of the deceleration space can be easily secured by appropriately adjusting the distance between the separation portion and the inner circumferential surface or the outer circumferential surface, and the distance between the two contact portions.

[0010] Furthermore, in the electric valve of the present invention, it is preferable that the space-forming portion is provided on the outer circumferential surface, and that at least two of the contact portions contact the inner circumferential surface from the fully open state to the fully closed state of the valve body. With such a configuration, even if the space-forming portion is provided on the valve body, it is easy to form a deceleration space regardless of the position of the valve body.

[0011] Furthermore, in the electric valve of the present invention, the space-forming portion has a valve-opening contact portion which is the contact portion located closest to the screw-feeding mechanism, and a valve-closing contact portion which is the contact portion located closest to the valve port, and it is preferable that the distance between the valve-opening contact portion and the valve-closing contact portion in the axial direction is greater than the distance the valve body moves from the fully open state to the fully closed state. With such a configuration, even if a space-forming portion is provided on the valve body, it is easy to form a deceleration space regardless of the position of the valve body.

[0012] The refrigeration cycle system of the present invention is a refrigeration cycle system including a compressor, a condenser, an expansion valve, and an evaporator, characterized in that an electric valve described in any of the above is used as the expansion valve. According to the present invention as described above, noise can be reduced as described above. [Effects of the Invention]

[0013] According to the electric valve and refrigeration cycle system of the present invention, noise can be reduced. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view showing an electric valve according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view showing the main part of the electric valve when the valve body is in a fully closed state. [Figure 3] This is a cross-sectional view showing the main part of the electric valve when the valve body is in the fully open position. [Figure 4] This is a system diagram showing a refrigeration cycle system equipped with the aforementioned electric valve. [Figure 5] This is a cross-sectional view showing the main part of the electric valve according to the first modified example when the valve body is in a fully closed state. [Figure 6] This is a cross-sectional view showing the main part of the electric valve according to the first modified example when the valve body is in the fully open position. [Figure 7] This is a cross-sectional view showing the main part of the electric valve according to the second modified example when the valve body is in a fully closed state. [Figure 8] It is a cross-sectional view showing the main part when the valve body reaches the fully open state in the electric valve according to the second modification example. [Figure 9] It is a cross-sectional view showing the main part when the valve body reaches the fully closed state in the electric valve according to the third modification example. [Figure 10] It is a cross-sectional view showing the main part when the valve body reaches the fully open state in the electric valve according to the third modification example.

Mode for Carrying Out the Invention

[0015] Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the electric valve 1 of the present embodiment is used in a refrigeration cycle system of an air conditioner such as a package air conditioner or a room air conditioner, and includes a valve housing 2, a valve body 3, a support member 4, a stepping motor 5, and a guide portion 6.

[0016] The valve housing 2 is composed of a valve housing main body 20A and an upper lid 20B, and the upper lid 20B is fixed to the upper end portion of the valve housing main body 20A to be described later by brazing. The valve housing main body 20A is formed in a cylindrical shape, and the valve body 3 is accommodated in the valve chamber 2A inside it. Hereinafter, the axial direction of the valve housing main body 20A is defined as the Z direction, and the two directions orthogonal to the Z direction are defined as the X direction and the Y direction, respectively. Also, hereinafter, the up and down in the Z direction are based on FIG. 1, the upper side (the side of the screw feed mechanism 55 with respect to the valve port 25) is the valve open side, and the lower side (the side of the valve port 25 with respect to the screw feed mechanism 55) is the valve closed side. A joint pipe 21 communicating with the valve chamber 2A is attached to the side surface of the valve housing main body 20A, and a cylindrical opening 22 is formed at the lower end portion. The end portion of a joint pipe 23 extending in the Z direction is inserted and connected to the cylindrical opening 22, and a valve seat portion 24 is integrally formed. The joint pipe 23 communicates with the valve port 25 of the valve seat portion 24.

[0017] The valve body 3 has a valve body member 31 and a valve holder 32. The valve body member 31 is fitted with the valve holder 32 and is suspended therefrom, extends downward from the valve holder 32, and has a needle valve 311 at its tip. The needle valve 311 seats or unseats with respect to a seal portion 26 (described later) of the valve seat portion 24.

[0018] The valve holder 32 is formed in a cylindrical shape extending along the Z direction, and its upper end portion is engaged with the lower end portion of a rotor shaft 51 (described later) of the stepping motor 5. That is, the valve holder 32 is suspended by the rotor shaft 51 and is rotatable with respect to the rotor shaft 51. Further, a compression coil spring 33 is provided inside the valve holder 32, and a downward load is applied to the valve body member 31. For convenience of explanation, the compression coil spring 33 is omitted and shown by a broken line in FIG. 1.

[0019] The support member 4 is fixed to the upper lid 20B at a flange portion 41 so as to close the upper opening of the valve housing 2 in the upper lid 20B. The support member 4 is formed with a guide recess 42 for accommodating the valve holder 32 and guiding it in the Z direction, a female screw portion 43 with which the rotor shaft 51 is screwed, and a pressure equalizing hole 44 that communicates the guide recess 42 with a second back pressure chamber 2C, which is a space inside a case 52 (described later) of the stepping motor 5.

[0020] The stepping motor 5 is composed of a rotor shaft 51, a case 52, a magnet rotor 53, and a stator coil 54. Inside the case 52, a magnet rotor 53 magnetized with multiple poles on its outer peripheral portion is provided rotatably (that is, the case 52 houses the magnet rotor 53 as a magnet), and the rotor shaft 51 is fixed to this magnet rotor 53. Further, the case 52 is fixed to the upper lid 20B so as to close the upper opening of the valve housing 2 in the upper lid 20B. The stator coil 54 is disposed on the outer periphery of the case 52. The stepping motor 5 rotates the magnet rotor 53 according to the number of pulses when a pulse signal is applied to the stator coil 54.

[0021] A male threaded portion 511 is formed on the outer circumferential surface of the rotor shaft 51, which engages with the female threaded portion 43 of the support member 4. When the stepping motor 5 is driven, the magnet rotor 53 and the rotor shaft 51 rotate, and the screw feed mechanism 55, which is composed of the male threaded portion 511 and the female threaded portion 43, moves the rotor shaft 51 in the Z direction. As a result, the valve holder 32 suspended from the rotor shaft 51 moves in the Z direction, guided by the guide recess 42 of the support member 4, causing the needle valve 311 of the valve body member 31 to seat or separate from the seal portion 26, and the valve port 25 to open and close. The opening degree of the valve port 25 is controlled according to the position (lift amount) of the valve body member 31 in the Z direction, and the flow rate of the fluid flowing through the valve port 25 is controlled.

[0022] As described above, the electric valve 1 includes a stepping motor 5 as a rotational driving means and a screw feed mechanism 55 that moves the valve body 3 axially forward and backward by converting the rotational motion of the rotor shaft 51 into linear motion.

[0023] The guide portion 6 is fixed to the upper opening of the valve housing body 20A. The guide portion 6 is formed in a cylindrical shape overall and has a through hole 61 extending along the Z direction, as shown in Figures 2 and 3. The valve body member 31 is inserted through the through hole 61, and the straight portion 312 of the valve body member 31, which extends along the Z direction, is positioned inside the through hole 61. The inner diameter of the through hole 61 is equal to or slightly larger than the outer diameter of the straight portion 312, so that the guide portion 6 can guide the valve body member 31 along the Z direction.

[0024] The guide portion 6 separates the valve chamber 2A from the first back pressure chamber 2B, which is the space above the valve chamber 2A and below the screw feed mechanism 55. At this time, the guide portion 6 has a pressure equalization hole 62, which connects the valve chamber 2A and the first back pressure chamber 2B. The first back pressure chamber 2B is connected to the second back pressure chamber 2C, which is the upper space separated by the support member 4, by a pressure equalization hole 44 formed in the support member 4 and a pressure equalization hole 411 that penetrates in the Z direction through the portion of the flange portion 41 that extends along the XY plane.

[0025] Here, the detailed structure of the portion where the valve body member 31 and the guide portion 6 slide against each other will be described with reference to Figures 2 and 3. First, the inner circumferential surface 61A of the through hole 61 of the guide portion 6 follows a cylinder with the Z direction as its axial direction and has no irregularities. The outer circumferential surface 31A of the straight portion 312 of the valve body member 31 has an irregular shape in which convex portions 313 and concave portions 314 are alternately arranged in the Z direction. The convex portions 313 and concave portions 314 have a rectangular cross-section, and each surface has a straight cross-section. In addition, the convex portions 313 and concave portions 314 are formed in an annular shape, and the convex portions 313 are independent of each other, as are the concave portions 314.

[0026] The outer diameter of the tip surface of the protrusion 313 is equal to the outer diameter of the entire straight section 312, and this tip surface is capable of contacting the inner circumferential surface 61A of the through hole 61. In other words, the protrusion 313 functions as a contact portion. The bottom surface and a pair of sides of the recess 314 are separated from the inner circumferential surface 61A of the through hole 61, and the recess 314 functions as a separation portion. The protrusion 313, which functions as a contact portion, is provided on both sides in the Z direction relative to the recess 314, which functions as a separation portion.

[0027] The formation of the convex portion 313 and recessed portion 314 on the outer circumferential surface 31A of the valve body member 31 creates a deceleration space S1 between the outer circumferential surface 31A and the inner circumferential surface 61A of the through hole 61. That is, the convex portion 313 and recessed portion 314 function as space-forming portions that form the deceleration space S1. The deceleration space S1 is enclosed and closed by the recessed portion 314 and the inner circumferential surface 61A, that is, it is closed by the inner circumferential surface 61A and the outer circumferential surface 31A. Furthermore, the deceleration space S1 is closed from both sides in the Z direction by the pair of convex portions 313. In this case, it is preferable that the Z-direction dimension of the convex portion 313 (length of the contact portion) is larger than the Z-direction dimension of the recessed portion 314 (length of the separation portion).

[0028] In the fully closed state of the valve body 3 shown in Figure 2, the protrusions 313 and recesses 314 located in the relatively upper region form the deceleration space S1. In the fully open state of the valve body 3 shown in Figure 3, the protrusions 313 and recesses 314 located in the relatively lower region form the deceleration space S1. Similarly, a deceleration space S1 is formed in an intermediate state between the fully open and fully closed states, and a deceleration space S1 is always formed regardless of the position of the valve body 3. In this way, at least one deceleration space S1 is formed from the fully open state to the fully closed state of the valve body 3.

[0029] Furthermore, at least two protrusions 313 are always in contact with the inner circumferential surface 61A of the through hole 61, from the fully open state to the fully closed state of the valve body 3. Also, the distance between the uppermost contact portion (protrusion 313), which is the valve open-side contact portion 313A, and the lowermost contact portion (protrusion 313), which is the valve closed-side contact portion 313B, is greater than the distance the valve body 3 travels from the fully open state to the fully closed state.

[0030] Next, an example of a refrigeration cycle system in which the electric valve 1 of this embodiment is installed will be described based on Figure 4. This refrigeration cycle system is used, for example, in air conditioners such as household air conditioners. The electric valve 1 is installed between the indoor heat exchanger 101 and the outdoor heat exchanger 104. The electric valve 1, indoor heat exchanger 101, four-way switching valve 102, compressor 103, and outdoor heat exchanger 104 constitute a refrigeration cycle. The indoor heat exchanger 101 and electric valve 1 are installed indoors, while the four-way switching valve 102, compressor 103, and outdoor heat exchanger 104 are installed outdoors, forming a heating and cooling system.

[0031] In the refrigeration cycle system described above, the four-way switching valve 102 switches between a state in which fluid flows into the valve chamber 2A from the side joint pipe 21 and a state in which fluid flows into the valve chamber 2A from the lower joint pipe 23. When fluid flows into the valve chamber 2A from the lower joint pipe 23, the fluid normally flows from the valve chamber 2A toward the side joint pipe 21. However, if the fluid pressure and velocity are high, some of the fluid will try to flow upward from the valve chamber 2A. Such fluid passes between the inner circumferential surface 61A of the through hole 61 of the guide section 6 and the outer circumferential surface 31A of the valve body 3 and flows into the deceleration space S1. As a result, the fluid is decelerated in the deceleration space S1, and pressure fluctuations in the valve chamber 2A are suppressed compared to a case where the deceleration space S1 is not formed.

[0032] According to this embodiment, a reduction space S1 is formed between the inner circumferential surface 61A of the through hole 61 of the guide portion 6 and the outer circumferential surface 31A of the valve body 3. This suppresses pressure fluctuations in the valve chamber 2A, making the valve body 3 less prone to vibration and thus reducing noise.

[0033] Furthermore, since at least one deceleration space S1 is formed from the fully open state to the fully closed state of the valve body 3, noise can be reduced regardless of the opening degree of the valve port 25.

[0034] Furthermore, since the deceleration space S1 is formed by a space-forming section having a recess 314 as a separation section and a protrusion 313 as a contact section, the volume of the deceleration space can be easily secured by appropriately adjusting the distance between the bottom surface of the recess 314 and the inner circumferential surface 61A of the through hole 61 of the guide section 6, and the distance between the two protrusions 313.

[0035] It should be noted that the present invention is not limited to the above-described embodiments, and includes other configurations that can achieve the objectives of the present invention, and modifications such as those shown below are also included in the present invention. In each of the modifications described below, components similar to those in the above embodiments are denoted by the same reference numerals and their descriptions are omitted. In the above embodiments, the space-forming portion is formed by the convex portion 313 and concave portion 314 provided on the outer peripheral surface 31A of the valve body 3, but the space-forming portion may be provided on the inner peripheral surface of the through hole of the guide portion, or it may be provided on both the inner peripheral surface of the through hole of the guide portion and the outer peripheral surface of the valve body. As examples in which the space-forming portion is provided on the inner peripheral surface of the through hole of the guide portion, the first and second modifications are shown in Figures 5 to 8, and as an example in which the space-forming portion is provided on both the inner peripheral surface of the through hole of the guide portion and the outer peripheral surface of the valve body, the third modification is shown in Figures 9 and 10.

[0036] As shown in Figures 5 and 6, in the first modified example, the outer circumferential surface 31A of the straight portion 312 of the valve body member 31 follows a cylinder with the Z direction as its axial direction and has no irregularities. On the other hand, the inner circumferential surface 71A of the through hole 71 of the guide portion 7 has an irregular shape in which convex portions 711 and concave portions 712 are alternately arranged in the Z direction. In the first modified example, four convex portions 711 and three concave portions 712 are formed, that is, multiple concave portions 712 are formed. The convex portions 711 become contact portions, and the concave portions 712 become separation portions.

[0037] In the first modified example, a space-forming portion is provided in the fixed guide portion 7, and a deceleration space S1 is always formed by all the recesses 712, regardless of the position of the valve body 3. Furthermore, when the valve body 3 is fully open, the lowest convex portion 711 does not need to contact the outer circumferential surface 31A of the valve body 3.

[0038] As shown in Figures 7 and 8, in the second modified example, the outer circumferential surface 31A of the straight portion 312 of the valve body member 31 follows a cylinder with the Z direction as its axial direction and has no irregularities. On the other hand, a recess 812 is formed between two protrusions 811 on the inner circumferential surface 81A of the through hole 81 of the guide portion 8. That is, the second modified example differs from the first modified example only in the number of protrusions and recesses, with only one recess 812 being formed.

[0039] As shown in Figures 9 and 10, in the third modified example, a large-diameter portion 315 and a small-diameter portion 316 located below the large-diameter portion 315 are formed on the outer circumferential surface 31A of the straight portion 312 of the valve body member 31. A large-diameter portion 911 and a small-diameter portion 912 located below the large-diameter portion 911 are formed on the inner circumferential surface 91A of the through hole 91 of the guide portion 9. The large-diameter portion 315 of the valve body member 31 is guided by contact with the large-diameter portion 911 of the guide portion 9, and the small-diameter portion 316 of the valve body member 31 is guided by contact with the small-diameter portion 912 of the guide portion 9. As a result, a reduction space S1 is formed between the outer circumferential surface 31A and the inner circumferential surface 91A, and between the large-diameter portion 315 and the small-diameter portion 912. Note that when the valve body 3 is in the fully closed state, the large-diameter portion 315 and the small-diameter portion 912 are separated.

[0040] In the third modification, space-forming portions are provided on both the outer circumferential surface 31A and the inner circumferential surface 91A. In addition, one deceleration space S1 is always formed regardless of the position of the valve body 3, and the size of the deceleration space S1 changes depending on the position of the valve body 3.

[0041] According to the third modification, there is no need to process recesses or grooves, making it easier to manufacture each part. Furthermore, there is no need to control the size or pitch of recesses or grooves, making it easier to reduce management costs.

[0042] Furthermore, in the above embodiment, the deceleration space S1 is formed by the rectangular cross-section convex portion 313 and concave portion 314, but the shape of the separation portion and contact portion for forming the deceleration space S1 is not particularly limited, and each portion of the separation portion and contact portion may have a curved cross-section. Also, the contact portion is not limited to contacting in a planar manner, but may also contact in a linear manner.

[0043] Furthermore, the detailed structure and operating method of the electric valve are not limited to the above embodiment. For example, in the above embodiment, the fixed side of the screw feeding mechanism 55 is the female screw portion 43 and the movable side is the male screw portion 511, but the movable side may be the female screw portion and the fixed side the male screw portion.

[0044] Furthermore, in the above embodiment, the valve body 3 comprises a valve body member 31 and a valve holder 32, and a space-forming portion is provided in the valve body member 31. However, the space-forming portion may be provided in the valve holder, or, as in the first and second modifications, the space-forming portion may be provided in the guide portion while a deceleration space is formed between the guide portion and the valve holder. Alternatively, the valve holder may be omitted, and the valve body may be configured such that the seated portion (or the portion closest to the valve port) rotates.

[0045] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design changes, etc., that do not depart from the spirit of the present invention are also included. [Explanation of Symbols]

[0046] 1...Electric valve, 2...Valve housing, 2A...Valve chamber, 25...Valve port, 3...Valve body, 31A...Outer surface, 313...Convex part (contact part), 314...Concave part (separation part), 313A...Valve open side contact part, 313B...Valve closed side contact part, 5...Stepping motor (rotational driving means), 51...Rotor shaft, 55...Screw feed mechanism, 6...Guide part, 61...Through hole, 61A...Inner surface, S1...Reduction space

Claims

1. An electric valve comprising: a valve housing; a valve body that changes the opening degree of a valve port in a valve chamber provided in the valve housing; a rotational drive means for rotating a rotor shaft; a screw feed mechanism that converts the rotational motion of the rotor shaft into linear motion to move the valve body axially back and forth; and a guide portion that guides the valve body axially between the valve port and the screw feed mechanism, An electric valve characterized in that, from the fully open state to the fully closed state of the valve body, at least one reduction space is formed between the inner circumferential surface of the through hole of the guide portion and the outer circumferential surface of the valve body, which is closed by both the inner circumferential surface and the outer circumferential surface, and is also closed from both sides in the axial direction.

2. The deceleration space is formed by a space-forming portion provided on one of the inner circumferential surface and the outer circumferential surface, The electric valve according to claim 1, characterized in that the space forming portion has a separation portion separated from the other of the inner circumferential surface and the outer circumferential surface, and contact portions provided on both sides in the axial direction relative to the separation portion and capable of contacting the other.

3. The space forming portion is provided on the outer peripheral surface, The electric valve according to claim 2, characterized in that at least two of the contact portions contact the inner circumferential surface from the fully open state to the fully closed state of the valve body.

4. The space forming portion has a valve open-side contact portion which is the contact portion located closest to the screw feeding mechanism, and a valve closed-side contact portion which is the contact portion located closest to the valve port. The electric valve according to claim 3, characterized in that the distance between the valve open-side contact portion and the valve closed-side contact portion in the axial direction is greater than the distance the valve body travels from the fully open state to the fully closed state.

5. A refrigeration cycle system comprising a compressor, a condenser, an expansion valve, and an evaporator, wherein the electric valve described in any one of claims 1 to 4 is used as the expansion valve.

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