Motor valve

Abstract

To reduce noise due to flow of a refrigerant at a valve port, in a motor valve that opens / closes the valve port with a needle valve to control a flow rate of the refrigerant.SOLUTION: In a valve housing 1, a first port 11 with a circular cross section and an inner diameter D1, a second port 12 with an inner diameter D2, a third port 13 with an inner diameter D3, a first tapered part 14, and a second tapered part 15 are formed. When a refrigerant flowing from a gap between the first port 11 and a needle valve 5a flows out to the second port 12, the flow is stabilized by rectifying the flow without rapidly recovering a pressure within the second port 12. This suppresses cavitation rupture. When flowing from the second port 12 to the second tapered part 15 and third port 15, the flow velocity is reduced to reduce flow velocity noise.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a needle valve type motor-operated valve for controlling the flow rate of refrigerant in an air conditioner or the like, and more particularly to a motor-operated valve having an improved shape of a valve port for a needle valve. [Background technology]

[0002] Conventionally, in refrigeration cycles, noise generated by an electric valve that controls the flow rate of a refrigerant and accompanying fluid passage has often been a problem. An example of an electric valve that has been designed to address this noise is disclosed in Japanese Patent No. 5696093 (Patent Document 1).

[0003] The motor-operated valve of Patent Document 1 has a valve port composed of a first port and a second port, with a tapered section provided between the first and second ports. Furthermore, the inner diameter of the second port is slightly larger than the inner diameter of the first port, and the length of the second port is sufficiently longer than the length of the first port.

[0004] In the design of Patent Document 1, as shown in FIG. 5, the refrigerant that passes through the gap between the needle valve a and the first port b flows through the tapered portion c and the second port d toward the secondary coupling tube. The refrigerant that passes through the gap between the needle valve a and the first port b follows the tapered portion c and flows along the inner wall of the second port d. The inner diameter of the second port d is only slightly larger than the inner diameter of the first port b, so there is no sudden recovery of pressure as the refrigerant flows from the first port b to the second port d. Furthermore, because the second port d is sufficiently long, the refrigerant flow is rectified at the second port d. This prevents cavitation from bursting, stabilizes the refrigerant flow, and reduces noise. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5696093 Summary of the Invention [Problem to be solved by the invention]

[0006] The invention of Patent Document 1 also has the effect of reducing noise, but there is a possibility that noise will be generated under certain refrigerant conditions. For example, in the invention of Patent Document 1, the fluid flow can be rectified in the second port, but this second port has an inner diameter slightly larger than that of the first port and is sufficiently longer than the first port. As a result, although the fluid is rectified, the flow velocity in this second port does not decrease, and noise may be generated due to flow velocity noise (sound caused by high flow velocity). In particular, under high loads, the differential pressure before and after the valve port is high, and this flow velocity noise is a major cause of noise.

[0007] An object of the present invention is to provide an electrically operated valve with reduced noise by improving the valve port. [Means for solving the problem]

[0008] The motor-operated valve of claim 1 is a motor-operated valve that allows a valve chest, which is connected to a primary joint pipe, to communicate with a secondary joint pipe via a valve port, and the valve port is provided with a first port provided on the valve chest side and whose opening area is increased or decreased by a needle valve, a second port having an inner diameter larger than that of the first port, an end port located at the end of the valve port on the secondary joint pipe side, and the secondary joint pipe having an inner diameter equal to or larger than that of the end port, in the motor-operated valve, the inner diameter of the end port is larger than that of the second port, and the first port and the second port and the second port are connected by a first taper, a second taper is connected to the second port on the side of the secondary coupling pipe, the first port, the second port, and the end port have the shape of a side surface of a cylinder centered on the same axis, the inner diameter of the valve port expands from the first port to the end port, the needle valve is insertable into the first taper and the second port, and the refrigerant that passes through the gap between the needle valve and the first port follows the first taper and immediately flows along the inner wall of the second port. The motor-operated valve of claim 2 is the motor-operated valve of claim 1, characterized in that a gap is formed between the outer peripheral surface from the second taper to the end port and the inner peripheral surface of the secondary coupling pipe, and the wall thickness of the valve port from the second taper to the end port becomes intermittently smaller toward the end port. The electric valve is also the electric valve described in claim 1, characterized in that the amount of expansion of the inner diameter from the first port to the end port is greater than the amount of expansion of the inner diameter from the end port to the secondary coupling pipe. The electric valve is also the electric valve described in claim 1, characterized in that the amount of expansion of the inner diameter from the second port to the end port is greater than the amount of expansion of the inner diameter from the first port to the second port. The motor-operated valve is the motor-operated valve according to claim 1, characterized in that the taper angle of the first taper connecting the first port and the second port is larger than the taper angle of the second taper connected to the secondary coupling pipe side of the second port. The motor-operated valve is the motor-operated valve according to claim 1, characterized in that the length of the second port in the axial direction is shorter than the inner diameter of the second port. Also, another electric valve is an electric valve that connects a valve chamber to which a primary joint pipe is connected and a secondary joint pipe via a valve port, and the valve port has a first port provided on the valve chamber side and having an opening area increased or decreased by a needle valve, a second port having a larger inner diameter than the first port, and in an electric valve provided with a first tapered portion connecting the first port and the second port, the valve port has a third port located on the secondary joint pipe side and a second tapered portion connecting the second port and the third port, and the relationship among the inner diameter D1 of the first port, the inner diameter D2 of the second port, and the inner diameter D3 of the third port is D1 < D2 < D3. The first port, the second port, and the third port each have the shape of the side surface of a cylinder centered on their respective axes. In the direction of the axis, when the length of the first port is L1, the length of the first tapered portion and the second port is L2, and the length of the second tapered portion and the third port is L3, 1 ≦ L3 / L2 ≦ 5. It is characterized in that an opening portion of the valve port on the secondary joint pipe side is located inside the secondary joint pipe. Also, in the electric valve, the opening portion of the valve port on the secondary joint pipe side may be located inside the inner peripheral surface of the secondary joint pipe, and the end portion of the secondary joint pipe on the valve chamber side may be located on the valve chamber side of the opening portion of the valve port on the secondary joint pipe side. Also, in the electric valve, the inner diameter of the second port may be larger than the length of the second port, and the inner diameter of the third port may be larger than the length of the third port. Also, a refrigeration cycle system is a refrigeration cycle system including a compressor that compresses a refrigerant, a condenser that condenses the compressed refrigerant, a throttling device that expands the condensed refrigerant, and an evaporator that evaporates the expanded refrigerant, and is characterized in that the above electric valve is used as the throttling device.

[0009] The electric valve is D2 - D1 ≦ D3 - D2 It is preferable that this holds.

[0010] Furthermore, in the motor-operated valve, when the taper angle of the first tapered portion is θ1, the taper angle of the second tapered portion is θ2, the length of the first port is L1, the length between the first tapered portion and the second port is L2, and the length between the second tapered portion and the third port is L3, 1mm≦D1≦4.5mm, 60°≦θ1≦150°, 20°≦θ2≦90°, 0.1mm≦L1≦0.5mm, 1≦L2 / L1≦39 1 <L3 / L2≦38 1.03≦D2 / D1≦1.5 1.02≦D3 / D2≦5.52 It is preferable that the following holds true. [Effects of the Invention]

[0011] With the motor-operated valve and refrigeration cycle system described above, when the refrigerant flowing through the gap between the first port and the needle valve flows out to the second port, the pressure in the second port is not suddenly restored, the flow is straightened and stabilized, and the bursting of cavitation can be suppressed. Furthermore, when the refrigerant flows from the second port to the second tapered section and the third port, the flow velocity is reduced, thereby reducing flow velocity noise. Therefore, noise can be reduced.

[0012] Furthermore, according to the preferred motor-operated valve described above, D2-D1≦D3-D2 holds, and therefore the diameter of the second port increases significantly from the second tapered section to the third port, thereby enhancing the effect of slowing down the flow velocity and further reducing flow velocity noise. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a longitudinal cross-sectional view of an embodiment of the motor-operated valve of the present invention. FIG. [Figure 2] FIG. 2 is an enlarged longitudinal cross-sectional view of a main portion near a valve port in the motor-operated valve according to the embodiment of the present invention. [Figure 3] 10A and 10B are diagrams illustrating the operation of a valve port in the motor-operated valve according to the embodiment of the present invention. [Figure 4] 1 is a diagram showing an example of an air conditioner using an electric valve according to an embodiment of the present invention. [Figure 5] 10A and 10B are diagrams illustrating the operation of a valve port of a conventional motor-operated valve. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an embodiment of the motor-operated valve of the present invention will be described with reference to the drawings. Fig. 1 is a longitudinal cross-sectional view of the motor-operated valve of the embodiment, Fig. 2 is an enlarged longitudinal cross-sectional view of a main portion near the valve port in the motor-operated valve of the embodiment, Fig. 3 is a diagram explaining the operation of the valve port in the motor-operated valve of the embodiment, and Fig. 4 is a diagram showing an example of an air conditioner using the motor-operated valve of the embodiment.

[0015] First, an air conditioner according to an embodiment will be described with reference to Fig. 4. The air conditioner includes the motor-operated valve 10 according to the embodiment, an outdoor heat exchanger 20 mounted in the outdoor unit 100, an indoor heat exchanger 30 mounted in the indoor unit 200, a flow path switching valve 40, and a compressor 50. These elements are connected by conduits as shown in the figure to form a heat pump refrigeration cycle. This refrigeration cycle is one example of a refrigeration cycle to which the motor-operated valve of the present invention can be applied, and the motor-operated valve of the present invention can also be applied to other systems, such as the throttling device on the indoor unit side of a multi-air conditioner for a building.

[0016] The flow path of the refrigeration cycle is switched between two flow paths, one for heating mode and one for cooling mode, by the flow path switching valve 40. In the heating mode, as indicated by the solid arrows, the refrigerant compressed by the compressor 50 flows from the flow path switching valve 40 into the indoor heat exchanger 30, and the refrigerant flowing out from the indoor heat exchanger 30 flows through a pipe 60 into the motor-operated valve 10. The refrigerant is then expanded by the motor-operated valve 10 and circulated through the outdoor heat exchanger 20, the flow path switching valve 40, and the compressor 50 in that order. In the cooling mode, as indicated by the dashed arrows, the refrigerant compressed by the compressor 50 flows from the flow path switching valve 40 into the outdoor heat exchanger 20, and the refrigerant flowing out from the outdoor heat exchanger 20 is expanded by the motor-operated valve 10 and flows through a pipe 60 into the indoor heat exchanger 30. The refrigerant that has flowed into the indoor heat exchanger 30 then flows into the compressor 50 via the flow path switching valve 40. In the example shown in FIG. 4, the refrigerant flows from the primary joint pipe 21 of the motor-operated valve 10 to the secondary joint pipe 22 during the heating mode, but the piping connections may be reversed so that the refrigerant flows from the secondary joint pipe 22 to the primary joint pipe 21 during the heating mode.

[0017] The motor-operated valve 10 functions as a throttle device to control the flow rate of the refrigerant, and in the heating mode, the outdoor heat exchanger 20 functions as an evaporator and the indoor heat exchanger 30 functions as a condenser to heat the room. In the cooling mode, the outdoor heat exchanger 20 functions as a condenser and the indoor heat exchanger 30 functions as an evaporator to cool the room.

[0018] Next, a motor-operated valve 10 according to an embodiment will be described with reference to Figures 1 and 2. The motor-operated valve 10 has a valve housing 1, which defines a cylindrical valve chamber 1A. The valve housing 1 also defines a first port 11, a second port 12, and a third port 13. A first tapered section 14 is formed between the first port 11 and the second port 12, and a second tapered section 15 is formed between the second port 12 and the third port 13. A primary coupling pipe 21 is attached to the valve housing 1 from its side, and communicates with the valve chamber 1A. A secondary coupling pipe 22 is attached to one end of the valve chamber 1A in the direction of the axis X. The valve chamber 1A and the secondary coupling pipe 22 are electrically connected via the first port 11, the first tapered section 14, the second port 12, the second tapered section 15, and the third port 13.

[0019] A support member 3 is attached to the upper part of the valve housing 1. A guide hole 3a that is long in the direction of axis X is formed in the support member 3, and a cylindrical valve holder 4 is fitted into this guide hole 3a so as to be slidable in the direction of axis X. The valve holder 4 is attached coaxially with the valve chamber 1A, and a valve element 5 having a needle valve 5a at its end is fixed to the lower end of the valve holder 4. A spring retainer 41 is provided within the valve holder 4 so as to be movable in the direction of axis X, and a compression coil spring 42 is attached between the spring retainer 41 and the valve element 5 with a predetermined load applied.

[0020] A case 61 of a stepping motor 6 is airtightly fixed to the upper end of the valve housing 1 by welding or the like. A magnet rotor 62, whose outer periphery is magnetized with multiple poles, is rotatably mounted within the case 61, and a rotor shaft 63 is fixed to the magnet rotor 62. The upper end of the rotor shaft 63 is rotatably fitted within a cylindrical guide 64 hanging down from the ceiling of the case 61. A stator coil 65 is disposed on the outer periphery of the case 61, and when a pulse signal is applied to the stator coil 65, the magnet rotor 62 rotates in accordance with the number of pulses. The rotation of the magnet rotor 62 then rotates the rotor shaft 63 integral with the magnet rotor 62. A rotation stopper mechanism 66 for the magnet rotor 62 is provided on the outer periphery of the guide 64.

[0021] The upper end of the valve holder 4 is engaged with the lower end of the rotor shaft 63 of the stepping motor 6, and the valve holder 4 is supported in a rotatable suspended state by the rotor shaft 63. The rotor shaft 63 is formed with a male thread 63a, which is threaded into a female thread 3b formed on the support member 3.

[0022] With the above configuration, the rotor shaft 63 moves in the direction of the axis X as the magnet rotor 62 rotates. The movement of the rotor shaft 63 in the direction of the axis X accompanying this rotation causes the valve element 5 to move in the direction of the axis X together with the valve holder 4. The valve element 5 increases or decreases the opening area of ​​the first port 11 at the needle valve 5a, thereby controlling the flow rate of the fluid flowing from the primary joint pipe 21 to the secondary joint pipe 22.

[0023] The first port 11, the second port 12, and the third port 13 each have the shape of a cylindrical side surface centered on the axis X. As shown in FIG. 2, the inner diameter D1 of the first port 11 is sized to fit the outer periphery of the needle valve 5a. The inner diameter D2 of the second port 12 is slightly larger than the inner diameter D1 of the first port 11. The inner diameter D3 of the third port 13 is larger than the inner diameter D21 of the second port 12 and smaller than the inner diameter D4 of the secondary coupling pipe 22. In FIG. 2, each of the diameters D1 to D4 is denoted by "φ" to indicate the diameter. The length L1 of the first port 11 is smaller than the inner diameter D1, and the combined length L2 of the first tapered section 14 and the second port 12 is larger than the length L1 of the first port 11. The combined length L3 of the second tapered portion 15 and the third port 13 is greater than the combined length L2 of the first tapered portion 14 and the second port 12.

[0024] The first tapered portion 14 and the second tapered portion 15 have the shape of a side surface of a circular truncated cone centered on the axis X, with the inner diameter of the inner surface of the first tapered portion 14 increasing from the first port 11 to the second port 12, and the inner diameter of the inner surface of the second tapered portion 15 increasing from the second port 12 to the third port 13. The taper angle θ1, which is the opening angle of the first tapered portion 14, and the taper angle θ2, which is the opening angle of the second tapered portion 15, are set appropriately. Note that these dimensions and angles are not limited to those shown in FIG. 2, and the conditions for these dimensions and angles will be described later.

[0025] As shown in FIG. 3, the refrigerant passing through the gap between the needle valve 5a and the first port 11 flows through the first tapered section 14, the second port 12, the second tapered section 15, and the third port 13 to the secondary coupling pipe 22. At this time, the gap between the needle valve 5a and the first port 11 is narrowest, where the flow velocity is greatest. However, because the length L1 of the first port 11 is as short as possible, the refrigerant passing through this gap follows the first tapered section 14 and immediately flows along the inner wall of the second port 12. The inner diameter D2 of the second port 12 is only slightly larger than the inner diameter D1 of the first port 11, so there is no sudden pressure recovery as the refrigerant flows from the first port 11 to the second port 12. Furthermore, because the second port 12 is long, the refrigerant flow is rectified in the second port 12. This prevents cavitation from bursting and stabilizes the refrigerant flow.

[0026] The refrigerant flow through second port 12 flows to third port 13 while recovering, or increasing, its pressure by following second tapered section 15. Because inner diameter D3 of third port 13 is larger than inner diameter D2 of second port 12, the flow velocity is decelerated as it flows along second tapered section 15. That is, the flow is straightened to a certain extent in second port 12 and then immediately decelerates, thereby reducing flow noise. Furthermore, the refrigerant flow that has been decelerated through second tapered section 15 flows to third port 13, but because the refrigerant flow has already been straightened in second port 12, the refrigerant flow is less likely to be turbulent within third port 13, thereby suppressing cavitation bursts.

[0027] In this way, by rectifying the flow to a certain extent at the second port 12 and then passing the flow through the second tapered section 15 to the third port 13, it is possible to reduce the flow velocity while maintaining the rectification at the second tapered section 15. This reduces flow turbulence at the third port 13, suppressing the collapse of cavitation, and also reduces flow velocity noise by slowing down the flow velocity at the second tapered section 15. In other words, the length of the second port 12 is shorter than that of Patent Document 1, and therefore flow velocity noise can be reduced accordingly.

[0028] The electric valve 10 in the embodiment has a high effect of reducing flow velocity noise when the pressure difference between the primary joint pipe 21 and the secondary joint pipe 22 is high, and the dimensions and angles of each part of the first port 11, the second port 12, the third port 13, the first tapered section 14, the second tapered section 15, and the secondary joint 22 are set to satisfy the following conditions.

[0029] Below are shown the conditions for the dimensions and angles of each part of an embodiment that has a high effect of reducing flow velocity sound when the pressure difference between the primary joint pipe 21 and the secondary joint pipe 22 is high. The inner diameter D1 of the first port 11 is: 1mm≦D1≦4.5mm and the inner diameter D2 of the second port 12 is 1.15mm≦D2≦4.9mm and the inner diameter D3 of the third port 13 is 4.6mm≦D3≦6.35mm and the inner diameter D4 of the secondary joint 22 is 6.35mm≦D4 is.

[0030] The taper angle θ1 of the first tapered portion 14 is 60°≦θ1≦150° The taper angle θ2 of the second tapered portion 15 is in the range of 20°≦θ2≦90° The range is.

[0031] The length L1 of the first port 11 is 0.1mm≦L1≦0.5mm The shorter L1 is, the lower the noise level becomes. The length L2 of the first tapered portion 14 and the second port 12 is 0.5mm≦L2≦3.9mm The combination of these lengths L1 and L2 is L1+L2, 1mm≦L1+L2≦4mm The sum L1 + L2 + L3 of the length L1 of the first port 11, the length L2 of the first tapered portion 14 and the second port 12, and the length L3 of the second tapered portion 15 and the third port 13 is set as follows: 6mm≦L1+L2+L3≦23mm It is as follows.

[0032] Also, the ratio L2 / L1 of the length L2 of the first tapered portion 14 and the second port 12 to the length L1 of the first port 11 is 1 ≦ L2 / L1 ≦ 39 within the range of, and the ratio L3 / L2 of the length L3 of the second tapered portion 15 and the third port 13 to the length L2 of the first tapered portion 14 and the second port 12 is 0.57 < L3 / L2 ≦ 38 (preferably, 1 < L3 / L2 ≦ 38) within the range of, and the dimensional ratio D2 / D1 of the inner diameter D2 of the second port 12 to the inner diameter D1 of the first port 11 is 1.03 ≦ D2 / D1 ≦ 1.5 within the range of, and the dimensional ratio D3 / D2 of the inner diameter D3 of the third port 13 to the inner diameter D2 of the second port 12 is 1.02 ≦ D3 / D2 ≦ 5.52 within the range of.

[0033] Next, each dimensional ratio of the electric valve of the embodiment and the measured example of noise reduction will be described. This measured example is a comparison between the noise measured with the electric valve of the embodiment and the noise measured with the electric valve of Patent Document 1 (under those conditions) under the operating conditions where the pressure in the primary joint pipe 21 is 2.8 to 3.4 (MPa) and the pressure in the secondary joint pipe 22 is 1.2 to 1.8 (MPa). That is, it is a measured example showing that the effect of noise reduction is particularly remarkable under conditions where flow velocity noise is likely to occur during high load. The measured examples are shown in Tables 1 to 6 below. In Tables 1 to 6, when the sound pressure has dropped by 2 dB or more compared to the noise in the electric valve of Patent Document 1, it is indicated by "○○○", and when the sound pressure has dropped by 1 to 2 dB, it is indicated by "○○". Also, when the drop in sound pressure is 1 dB or less, it is indicated by "○". Note that the sound pressure is evaluated using the A characteristic.

[0034] Table 1 shows the relationship between L2 / L1 and θ1.

[0035]

Table 1

[0036] Table 2 shows the relationship between L2 / L1 and D2 / D1.

[0037] [Table 2]

[0038] Table 3 shows the relationship between L2 / L1 and θ2.

[0039] [Table 3]

[0040] Table 4 shows the relationship between L2 / L1 and D3 / D2.

[0041] [Table 4]

[0042] Table 5 shows the relationship between D3 / D2 and θ2.

[0043] [Table 5]

[0044] Table 6 shows the relationship between D3 / D2 and L3 / L2.

[0045] [Table 6]

[0046] As can be seen from these tables, the provision of the third port and second tapered section achieves a reduction in noise compared to conventional methods. Furthermore, even when the pressure difference between the primary joint pipe 21 and the secondary joint pipe 22 is high, noise can be reduced by 1 dB or more if the ranges are set to "XX" and "XXX", achieving a more significant effect.

[0047] The embodiments of the present invention have been described in detail above with reference to the drawings, but the specific configurations are not limited to these embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention. [Explanation of symbols]

[0048] 1 Valve housing 1A Valve chamber 11 Port 1 12 Second port 13 Third Port 14 First tapered section 15 Second tapered section 21 Primary joint pipe 22 Secondary joint pipe 3 Support member 4 Valve holder 5 Valve body 5a Needle valve 6 stepping motors X axis

Claims

1. A motor-operated valve that allows a valve chest, which is in communication with a primary joint pipe, to communicate with a secondary joint pipe via a valve port, the motor-operated valve comprising: a first port provided on the valve chest side and having an opening area increased or decreased by a needle valve; a second port having an inner diameter larger than that of the first port; an end port located at an end of the valve port on the secondary joint pipe side; and the secondary joint pipe having an inner diameter equal to or larger than that of the end port, an inner diameter of the end port greater than an inner diameter of the second port; the first port and the second port are connected by a first taper, a second taper is connected to the second port on the secondary coupling pipe side; the first port, the second port, and the end port have the shape of a side surface of a cylinder centered on the same axis; an inner diameter of the valve port increasing from the first port to the end port; the needle valve is insertable into the first taper and the second port; The refrigerant that passes through the gap between the needle valve and the first port follows the first taper and immediately flows along the inner wall of the second port.

2. a gap is formed between an outer peripheral surface of the secondary coupling pipe from the second taper to the end port and an inner peripheral surface of the secondary coupling pipe, 2. The motor-operated valve according to claim 1, wherein the wall thickness of the valve port from the second taper to the end port decreases discontinuously toward the end port.

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