Valve body assembly and electric valve

Abstract

To provide an electric valve which enables effective reduction of noise generated when a refrigerant flows through a valve port, and to provide a valve main part assembly included in the electric valve.SOLUTION: An electric valve has a valve seat member 11 provided with a valve port 30. The valve port 30 has a first peripheral surface 31, a first taper surface 32 having a diameter increasing in a direction away from a valve seat 16, a second peripheral surface 33 having a diameter larger than that of the first peripheral surface 31, a first connection part 34, a third peripheral surface 35 having a diameter larger than that of the second peripheral surface 33, a second connection part 36, and a second taper surface 37 having a diameter increasing in a direction away from the valve seat 16, which are sequentially connected from the valve seat 16 side along an axis K. The first connection part 34 has a first annular surface 34a connected at an inner peripheral edge with the second peripheral surface 33. The second connection part 36 has a second annular surface 36a connected at an inner peripheral edge with the third peripheral surface 35. An angle α formed between the axis K and the first annular surface 34a is 90 degrees. An angle β formed between the axis K and the second annular surface 36a is 90 degrees.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an electric valve such as a flow control valve used for adjusting the flow rate of a refrigerant in, for example, a heat pump type air conditioning system, and a valve body assembly included in the electric valve.

Background Art

[0002] Patent Document 1 discloses an example of a conventional electric valve. The electric valve has a valve seat member provided with a valve port. The valve seat member is shown in FIG. 11. The valve seat member 911 in FIG. 11 has a valve seat 916 and a valve port 930. The valve port 930 has a first circumferential surface 931, a first tapered surface 932, a second circumferential surface 933, a second tapered surface 934, a third circumferential surface 935, a third tapered surface 936, and a fourth circumferential surface 937, which are connected in order from the valve seat 916 side in the direction of the axis K. The diameter of the second circumferential surface 933 is larger than the diameter of the first circumferential surface 931. The diameter of the third circumferential surface 935 is larger than the diameter of the second circumferential surface 933. The diameter of the fourth circumferential surface 937 is larger than the diameter of the third circumferential surface 935.

[0003] Although cavitation may occur due to a pressure drop in the vicinity of the first circumferential surface 931 and the first tapered surface 932 in the refrigerant flowing into the valve port 930 from the valve seat 916 side, the pressure is recovered and the cavitation is eliminated by flowing sequentially through the second circumferential surface 933, the second tapered surface 934, the third circumferential surface 935, and the fourth circumferential surface 937. As a result, the noise generated when the refrigerant flows through the valve port 930 is reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the valve opening 930 is relatively small, the flow velocity of the refrigerant flowing through the valve opening 930 is relatively high, which can cause cavitation. When the valve opening 930 is relatively large, the flow velocity of the refrigerant flowing through the valve opening 930 is relatively low, and the occurrence of cavitation is suppressed. However, if the refrigerant flow velocity is relatively low, as schematically shown in Figure 12, periodic vortices S may be generated near the inner surface of the valve opening 930, and noise (for example, a continuous "beeping" sound) may be produced by a series of periodic vortices S. The periodic vortices S then advance along the second circumferential surface 933, the third circumferential surface 935, and the fourth circumferential surface 937, and when the periodic vortices S reach the second tapered surface 934 and the third tapered surface 936, the periodic vortices S increase in size as the diameters of the second tapered surface 934 and the third tapered surface 936 expand. This can increase the noise generated when the refrigerant flows through the valve opening 930.

[0006] Therefore, the present invention aims to provide an electric valve and a valve body assembly for the electric valve that can effectively reduce noise generated when refrigerant flows through the valve opening. [Means for solving the problem]

[0007] To achieve the above objective, a valve body assembly according to one aspect of the present invention is a valve body assembly having a valve body provided with a valve chamber and a valve port, and a valve element disposed in the valve chamber and facing the valve port, wherein the valve port has a first circumferential surface connected in order along the axis from the valve chamber side, a first tapered surface whose diameter increases as it moves away from the valve chamber, a second circumferential surface having a larger diameter than the first circumferential surface, a first connecting portion, a third circumferential surface having a larger diameter than the second circumferential surface, a second connecting portion, and a second tapered surface whose diameter increases as it moves away from the valve chamber, wherein the first connecting portion has a first annular surface whose inner edge is connected to the second circumferential surface, the second connecting portion has a second annular surface whose inner edge is connected to the third circumferential surface, the angle between the axis and the first annular surface is 90 degrees or less, and the angle between the axis and the second annular surface is 90 degrees or less.

[0008] In the present invention, it is preferable that the first connecting portion has a first annular groove surrounding the first annular surface.

[0009] In the present invention, it is preferable that the second connecting portion has a second annular groove surrounding the second annular surface.

[0010] In the present invention, it is preferable that the first connecting portion has a first annular groove surrounding the second circumferential surface, and the inner circumferential surface of the first annular groove is the first annular surface.

[0011] In the present invention, it is preferable that the second connecting portion has a second annular groove surrounding the third circumferential surface, and the inner circumferential surface of the second annular groove is the second annular surface.

[0012] In the present invention, when the diameter of the first circumferential surface is D1 and the diameter of the second circumferential surface is D2, it is preferable that the following formula (1) is satisfied. (1) 1 <D2 / D1<1.5

[0013] In the present invention, when the diameter of the second circumferential surface is D2, the axial length of the second circumferential surface is L2, and the axial length of the portion of the valve opening that combines the first connection portion and the third circumferential surface is L3, it is preferable that the following equations (2) and (3) are satisfied. (2) L2≧L3 (3) 5 > (L2 + L3) / D2 ≥ 2

[0014] To achieve the above objective, an electric valve according to another aspect of the present invention comprises a valve body assembly and a stator unit attached to the valve body assembly, wherein the valve body assembly has a magnetic rotor, the stator unit has a stator, and the magnetic rotor and the stator constitute a motor for moving the valve body. [Effects of the Invention]

[0015] According to the present invention, at the valve port, the angle formed by the axis and the first annular surface is 90 degrees or less. Due to this, the periodic vortex advances along the axis inside the second circumferential surface, and when the periodic vortex reaches the first annular surface, it advances straight inside the third circumferential surface without advancing along the first annular surface. Therefore, the periodic vortex advances away from the third circumferential surface, gradually becomes smaller, and disappears. Accordingly, the noise generated by the periodic vortex when the refrigerant flows through the valve port can be effectively reduced.

Brief Description of the Drawings

[0016] [Figure 1] It is a cross-sectional view of an electric valve according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of the valve seat member of the electric valve in FIG. 1 and its vicinity. [Figure 3] It is a cross-sectional view of the valve seat member of the electric valve in FIG. 1. [Figure 4] It is a cross-sectional view of the valve port of the valve seat member in FIG. 3 and its vicinity. [Figure 5] It is a diagram schematically showing the fluctuation of the refrigerant pressure due to the row of periodic vortices. [Figure 6] It is a cross-sectional view showing the configuration of the first modification example of the valve seat member in FIG. 3. [Figure 7] It is a cross-sectional view showing the configuration of the second modification example of the valve seat member in FIG. 3. [Figure 8] It is a cross-sectional view showing the configuration of the third modification example of the valve seat member in FIG. 3. [Figure 9] It is a cross-sectional view showing the configuration of the fourth modification example of the valve seat member in FIG. 3. [Figure 10] It is a cross-sectional view showing the configuration of the fifth modification example of the valve seat member in FIG. 3. [Figure 11] It is a cross-sectional view of the valve seat member of a conventional electric valve. [Figure 12] It is a cross-sectional view of the valve port of the valve seat member in FIG. 11 and its vicinity.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an electric valve according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10.

[0018] Figure 1 is a cross-sectional view of an electric valve according to one embodiment of the present invention. Figure 2 is a cross-sectional view of the valve seat member of the electric valve of Figure 1 and its vicinity. Figure 3 is a cross-sectional view of the valve seat member of the electric valve of Figure 1. Figure 4 is a cross-sectional view of the valve port of the valve seat member of Figure 3 and its vicinity. A periodic vortex is schematically shown in Figure 4. Figure 5 is a diagram schematically showing the refrigerant pressure in a row of periodic vortices. Figures 6 to 10 are cross-sectional views showing the configuration of the first to fifth modified examples of the valve seat member of Figure 3.

[0019] The electric valve 1 according to this embodiment is used, for example, to adjust the flow rate of refrigerant in a heat pump type heating and cooling system.

[0020] As shown in Figures 1 and 2, the electric valve 1 comprises a valve body assembly 5 and a stator unit 9. The valve body assembly 5 comprises a valve body 10, a valve element 40, a cann 50, a guide stem 60, a valve shaft 70, a coupling mechanism 78, and a magnet rotor 80.

[0021] The valve body 10 includes a valve seat member 11 and a case member 18.

[0022] The valve seat member 11 is manufactured, for example, by machining a metal material such as stainless steel. The valve seat member 11 integrally comprises a base portion 12, a peripheral wall portion 13, and a cylindrical portion 14.

[0023] The base portion 12 has a disc shape. A valve seat 16 is provided on the upper surface 12a of the base portion 12. The valve seat 16 is an annular tapered surface facing radially inward, and its diameter decreases as it moves away from the upper surface 12a. The peripheral wall portion 13 has a cylindrical shape and extends upward from the upper surface 12a of the base portion 12. The peripheral wall portion 13 surrounds the valve seat 16. The cylindrical portion 14 extends downward from the lower surface 12b of the base portion 12. Inside the valve seat 16, a valve opening 30 is provided that penetrates the base portion 12 and the cylindrical portion 14 in the axial direction K (vertical direction).

[0024] The valve seat member 11 is joined to the lower end of a cylindrical case member 18. The peripheral wall portion 13 is located inside the lower end of the case member 18. The valve seat member 11 and the case member 18 form a valve chamber 15. A first conduit 6 is joined to the case member 18. The first conduit 6 penetrates the case member 18 in a direction perpendicular to the axis K and is connected to the valve chamber 15. The refrigerant flowing from the first conduit 6 into the valve chamber 15 is straightened by the peripheral wall portion 13 so as to flow towards the valve opening 30.

[0025] A circular annular groove 17 is provided on the lower surface 12b of the base portion 12. The annular groove 17 surrounds the cylindrical portion 14. The inner circumferential surface of the annular groove 17 (the circumferential surface facing radially outward, positioned radially inward) is coaxial with the outer circumferential surface of the cylindrical portion 14 and is connected to the outer circumferential surface without any step difference. The upper end of the second conduit 7 is positioned in the annular groove 17. The cylindrical portion 14 is positioned inside the upper end of the second conduit 7. The upper end of the second conduit 7 is joined to the base portion 12.

[0026] As shown in Figure 3, the valve opening 30 has a first circumferential surface 31, a first tapered surface 32, a second circumferential surface 33, a first connecting portion 34, a third circumferential surface 35, a second connecting portion 36, and a second tapered surface 37, which are connected in order from the valve chamber 15 (valve seat 16) side in the direction of the axis K.

[0027] The first circumferential surface 31 is a cylindrical circumferential surface facing radially inward. The first circumferential surface 31 has a constant diameter along its entire axis K direction. The first circumferential surface 31 is connected to the lower end of the valve seat 16.

[0028] The first tapered surface 32 is an annular tapered surface facing radially inward, with its diameter increasing as it moves away from the valve chamber 15. The inner periphery of the first tapered surface 32 is connected to the first circumferential surface 31. The taper angle of the first tapered surface 32 is preferably 90 degrees or less. The taper angle is the angle between the two generatrixes of a cone in a single axial cross-section.

[0029] The second circumferential surface 33 is a cylindrical circumferential surface facing radially inward. The second circumferential surface 33 has a constant diameter throughout the axial direction of the axis K. The second circumferential surface 33 is connected to the outer peripheral edge of the first tapered surface 32. The diameter D2 of the second circumferential surface 33 is larger than the diameter D1 of the first circumferential surface 31. It is preferable that the diameter D2 is larger than 1 times and smaller than 1.5 times the diameter D1 (1 < D2 / D1 < 1.5). The length L2 of the second circumferential surface 33 in the axial direction of the axis K is longer than the length L1 of the first circumferential surface 31 in the axial direction of the axis K (L2 > L1).

[0030] The first connecting portion 34 connects the second circumferential surface 33 and the third circumferential surface 35. The first connecting portion 34 has a first annular surface 34a and an intermediate tapered surface 34b. The first annular surface 34a is an annular plane orthogonal to the axial direction of the axis K. The inner peripheral edge of the first annular surface 34a is connected to the second circumferential surface 33. The angle α formed by the axis K (that is, the second circumferential surface 33) and the first annular surface 34a is 90 degrees. It is preferable that the angle α is 90 degrees or less. FIG. 3 shows the angle α. The intermediate tapered surface 34b is an annular tapered surface facing radially inward, and the diameter increases as it moves away from the valve chamber 15. The inner peripheral edge of the intermediate tapered surface 34b is connected to the outer peripheral edge of the first annular surface 34a. It is preferable that the taper angle of the intermediate tapered surface 34b is 90 degrees or less. The first connecting portion 34 may omit the intermediate tapered surface 34b and have only the first annular surface 34a.

[0031] The third circumferential surface 35 is a cylindrical circumferential surface facing radially inward. The third circumferential surface 35 has a constant diameter throughout the axial direction of the axis K. The third circumferential surface 35 is connected to the outer peripheral edge of the intermediate tapered surface 34b of the first connecting portion 34. The diameter D3 of the third circumferential surface 35 is larger than the diameter D2 of the second circumferential surface 33. The length L2 of the second circumferential surface 33 in the axial direction of the axis K is longer than the length L3 of the combined portion of the first connecting portion 34 and the third circumferential surface 35 at the valve port 30 in the axial direction of the axis K. It is preferable that the length L2 is equal to or greater than the length L3 (L2 ≧ L3). Also, it is preferable that the combined length (L2 + L3) of the second circumferential surface 33, the first connecting portion 34, and the third circumferential surface 35 at the valve port 30 is more than 2 times and less than 5 times the diameter D2 of the second circumferential surface 33 (5 > (L2 + L3) / D2 ≧ 2).

[0032] The second connecting portion 36 connects the third circumferential surface 35 and the second tapered surface 37. The second connecting portion 36 has a second annular surface 36a. The second annular surface 36a is an annular plane perpendicular to the axis K direction. The inner edge of the second annular surface 36a is connected to the third circumferential surface 35. The angle β between the axis K (i.e., the third circumferential surface 35) and the second annular surface 36a is 90 degrees. It is preferable that the angle β is 90 degrees or less. Figure 3 shows the angle β.

[0033] The second tapered surface 37 is an annular tapered surface facing radially inward, with its diameter increasing as it moves away from the valve chamber 15. The inner periphery of the second tapered surface 37 is connected to the outer periphery of the second annular surface 36a of the second connecting portion 36. The outer periphery of the second tapered surface 37 is connected to the inner periphery of the lower end surface of the cylindrical portion 14. The taper angle of the second tapered surface 37 is preferably 90 degrees or less.

[0034] The valve body 40 has a body portion 41, a seat portion 42, and a control portion 43, which are connected in order from top to bottom.

[0035] The body portion 41 has a cylindrical shape. The seat portion 42 has a frustoconical shape, with its diameter decreasing as it approaches the bottom. The outer circumferential surface of the seat portion 42 is an annular tapered surface facing radially outward. The control unit 43 has a substantially conical shape facing the valve opening 30. In this embodiment, the control unit 43 has a shape that approximates an equal percentage characteristic as a flow rate characteristic. The control unit 43 has a plurality of tapered surface portions connected in the direction of the axis K. The plurality of tapered surface portions are arranged such that the taper angle increases in stages as they approach the tip, forming a pseudo-ellipsoidal surface. The control unit 43 may also have a shape that obtains a linear characteristic as a flow rate characteristic.

[0036] The valve body 40 is located in the valve chamber 15, and the control unit 43 is facing the valve port 30 in the direction of axis K. The valve body 40 is moved in the direction of axis K. When the seating portion 42 contacts the valve seat 16, the valve port 30 closes. The opening degree of the valve port 30 changes according to the distance (lift amount) between the valve body 40 and the valve seat 16, and the flow rate of the refrigerant flowing through the valve port 30 changes.

[0037] The can 50 has a cylindrical shape with an open lower end and a closed upper end. The lower end of the can 50 is joined to the upper end surface of the case member 18 of the valve body 10.

[0038] The guide stem 60 integrally comprises a guide portion 61 and a valve stem support portion 62. The guide portion 61 has a cylindrical shape. The guide portion 61 is joined to the upper end surface of the case member 18 via a connecting plate 63. The valve stem support portion 62 has a cylindrical shape and is coaxially connected to the upper end of the guide portion 61. The valve stem support portion 62 has an internal thread 65. The guide stem 60 is positioned to span the inside of the case member 18 and the inside of the can 50.

[0039] The valve stem 70 has a cylindrical shape. The valve stem 70 has a male thread 75. The male thread 75 is screwed into the female thread 65 of the guide stem 60. The lower end of the valve stem 70 is connected to the valve body 40 via a cylindrical connecting mechanism 78. The connecting mechanism 78 is slidably positioned inside the guide portion 61 in the axial direction K. In Figures 1 and 2, the valve body 40 and the connecting mechanism 78 are shown in a front view.

[0040] The magnet rotor 80 integrally comprises a peripheral wall portion 81 and an upper wall portion 82. The peripheral wall portion 81 has a cylindrical shape. The upper wall portion 82 has a disc shape. Peripheral wall part 81 It is connected to the upper end of the can 50. The magnet rotor 80 is rotatably positioned inside the can 50. The upper end 71 of the valve stem 70 is fixed to the upper wall portion 82. The valve stem 70 rotates together with the magnet rotor 80.

[0041] The stator unit 9 is attached to the valve body assembly 5. The stator unit 9 has a stator 90. The stator 90 has a cylindrical shape. A can 50 is positioned inside the stator 90. The stator 90 generates a magnetic field that rotates the magnet rotor 80 in one direction and in other directions. The magnet rotor 80 and the stator 90 constitute a motor 100 (for example, a stepping motor).

[0042] In the electric valve 1, the central axes of the valve seat member 11 (base 12, circumferential wall 13, cylindrical part 14, valve seat 16, annular groove 17, valve port 30), case member 18, valve body 40, cann 50, guide stem 60 (female thread 65), valve stem 70 (male thread 75), magnet rotor 80, and stator 90 all coincide with axis K. The central axes of the first circumferential surface 31, first tapered surface 32, second circumferential surface 33, first connecting part 34 (first annular surface 34a, intermediate tapered surface 34b), third circumferential surface 35, second connecting part 36 (second annular surface 36a), and second tapered surface 37 of the valve port 30 all coincide with axis K. The normal direction of the first annular surface 34a and the normal direction of the second annular surface 36a of the valve port 30 coincide with axis K.

[0043] In the electric valve 1, when the stator 90 is energized, the magnet rotor 80 rotates. The valve stem 70 rotates together with the magnet rotor 80, and the valve stem 70 and the magnet rotor 80 move in the axial direction K (up and down direction) due to the feed screw action between the female thread 65 of the guide stem 60 and the male thread 75 of the valve stem 70. When the valve stem 70 moves downward and the valve body 40 comes into contact with the valve seat 16, the valve port 30 closes and the flow of refrigerant stops (valve closed state). When the valve stem 70 moves upward and the valve body 40 moves away from the valve seat 16, refrigerant flows at a flow rate corresponding to the opening of the valve port 30 (valve open state).

[0044] Next, we will explain the state of the refrigerant flowing through valve port 30.

[0045] When the opening of the valve port 30 is relatively small, the flow velocity of the refrigerant flowing from the valve chamber 15 into the valve port 30 is relatively fast, and cavitation may occur in the refrigerant due to a pressure drop near the first circumferential surface 31 and the first tapered surface 32. Then, as the refrigerant flows sequentially through the second circumferential surface 33, the first connection part 34, and the third circumferential surface 35, the pressure recovers and the cavitation is eliminated. Therefore, the noise generated by cavitation when the refrigerant flows through the valve port 30 is reduced.

[0046] Furthermore, when the valve opening 30 is relatively large, the flow velocity of the refrigerant flowing through the valve opening 30 is relatively slow, and periodic vortices S are generated on the second circumferential surface 33 as shown in Figure 4. The periodic vortices S move in a line along the axis K inside the second circumferential surface 33, and when the periodic vortices S reach the first annular surface 34a of the first connection part 34, they do not move along the first annular surface 34a but instead move straight towards the inside of the third circumferential surface 35. As a result, the periodic vortices S move away from the third circumferential surface 35, gradually become smaller, and disappear. Consequently, the noise generated by the periodic vortices S when the refrigerant flows through the valve opening 30 is reduced.

[0047] Furthermore, as shown in Figure 4, periodic vortices S' may be generated on the third circumferential surface 35. The refrigerant pressure is relatively low at the center of periodic vortex S, and relatively high at the centers of two adjacent periodic vortices S in the direction of axis K. Similarly, the refrigerant pressure is relatively low at the center of periodic vortex S', and relatively high at the centers of two adjacent periodic vortices S' in the direction of axis K. Then, the rows of periodic vortices S and the rows of periodic vortices S' are arranged in parallel, and in order to balance the pressure, periodic vortices S The position of the axial K corresponds to the center of two adjacent periodic vortices S' in the axial K direction. As a result, the refrigerant pressure distribution waveforms in the row of periodic vortices S and the refrigerant pressure distribution waveforms in the row of periodic vortices S' have the same period and are shifted by half a wavelength, causing them to cancel each other out. Therefore, the noise generated by the periodic vortices S and S' when the refrigerant flows through the valve port 30 is reduced.

[0048] Figure 5 schematically shows the distribution waveforms of refrigerant pressure in a row of periodic vortices S and in a row of periodic vortices S'. The horizontal axis in Figure 5 represents the position within the valve port 30 (position along the axis K on the third circumferential surface 35), and moving to the right moves away from the first connection part 34. The vertical axis in Figure 5 represents the refrigerant pressure, and moving upwards increases the refrigerant pressure. The bottom of each waveform corresponds to the center of the periodic vortex, and the peak of each waveform corresponds to the center of two adjacent periodic vortices along the axis K.

[0049] As described above, the valve body assembly 5 of the electric valve 1 includes a valve body 10 provided with a valve chamber 15 and a valve port 30, and a valve body 40 positioned in the valve chamber 15 and facing the valve port 30. The valve port 30 has, in order from the valve chamber 15 side along the axis K, a first circumferential surface 31, a first tapered surface 32 whose diameter increases as it moves away from the valve chamber 15, a second circumferential surface 33 which has a larger diameter than the first circumferential surface 31, a first connecting portion 34, a third circumferential surface 35 which has a larger diameter than the second circumferential surface 33, a second connecting portion 36, and a second tapered surface 37 whose diameter increases as it moves away from the valve chamber 15. The first connecting portion 34 has a first annular surface 34a whose inner edge is connected to the second circumferential surface 33. The second connecting portion 36 has a second annular surface 36a whose inner edge is connected to the third circumferential surface 35. The angle α between axis K and the first annular surface 34a is 90 degrees. The angle β between axis K and the second annular surface 36a is 90 degrees. Angles α and β may be less than 90 degrees.

[0050] As a result, when the refrigerant flows from the valve chamber 15 to the valve opening 30, the periodic vortex S generated within the valve opening 30 travels along the axis K inside the second circumferential surface 33. When the periodic vortex S reaches the first annular surface 34a, it does not travel along the first annular surface 34a but instead travels straight inside the third circumferential surface 35. Therefore, the periodic vortex S moves away from the third circumferential surface 35, gradually shrinking and disappearing. Consequently, the noise generated by the periodic vortex S when the refrigerant flows through the valve opening 30 can be effectively reduced.

[0051] Furthermore, when the refrigerant flows from the second conduit 7 to the valve opening 30, the bubbles in the refrigerant are crushed and miniaturized at the corner formed by the third circumferential surface 35 and the second annular surface 36a, thereby effectively reducing noise. At this time, the second tapered surface 37 creates a flow from the radially outward to the inward direction, collecting bubbles in the refrigerant and increasing the speed at which the refrigerant passes through the corner, thereby promoting the miniaturization of bubbles.

[0052] Furthermore, when the diameter of the first circumferential surface 31 is D1 and the diameter of the second circumferential surface 33 is D2, the following equation (1) is satisfied. (1) 1 <D2 / D1<1.5 In this way, the difference in height between the first surface 31 and the second surface 33 is small, so the size of the periodic vortex S generated on the second surface 33 is reduced, and the noise generated by the periodic vortex S can be reduced more effectively.

[0053] Furthermore, when the length of the second circumferential surface 33 in the axial direction K is L2, and the length of the portion of the valve opening 30 that combines the first connecting portion 34 and the third circumferential surface 35 in the axial direction K is L3, the following equations (2) and (3) are satisfied. (2) L2≧L3 (3) 5 > (L2 + L3) / D2 ≥ 2 If the length L2 of the second circumferential surface 33 is insufficient relative to the diameter D2, the periodic vortex S cannot be properly advanced toward the first connection part 34 on the second circumferential surface 33. Also, if the length (L2+L3) in the axial direction K of the portion of the valve opening 30 that combines the second circumferential surface 33, the first connection part 34, and the third circumferential surface 35 is too small or too large relative to the diameter D2, the effect of eliminating cavitation in the valve opening 30 will be reduced. Therefore, in the electric valve 1, by satisfying the above equations (2) and (3), the periodic vortex S within the second circumferential surface 33 toward the first connection part 34 It can be properly advanced toward the third circumferential surface 35 and eliminated inside, and cavitation can be effectively eliminated at the valve opening 30.

[0054] Next, the first to fifth modified examples of the valve seat member 11 described above will be explained with reference to Figures 6 to 10. In the following explanation, components that are the same as (including substantially the same as) the valve seat member 11 are denoted by the same reference numerals and detailed explanations are omitted.

[0055] The valve seat member 11A shown in Figure 6 is provided with a valve opening 30A. The valve opening 30A has a first circumferential surface 31, a first tapered surface 32, a second circumferential surface 33, a first connecting portion 34, a third circumferential surface 35, a second connecting portion 36, and a second tapered surface 37, which are connected in order from the valve seat 16 side in the direction of the axis K. The valve opening 30A has the same configuration as the valve opening 30, except that the length of the second circumferential surface 33 in the direction of the axis K (L2) is shorter than the combined length of the first connecting portion 34 and the third circumferential surface 35 in the valve opening 30A (L3).

[0056] The valve seat member 11B shown in Figure 7 is provided with a valve opening 30B. The valve opening 30B has a first circumferential surface 31, a first tapered surface 32, a second circumferential surface 33, a first connecting portion 34B, a third circumferential surface 35, a second connecting portion 36, and a second tapered surface 37, which are connected in order from the valve seat 16 side in the direction of the axis K.

[0057] The first connecting portion 34B has a first annular surface 34a and a first annular groove 34c. The first annular groove 34c surrounds the first annular surface 34a. The first annular groove 34c has an inner circumferential surface 34c1, a bottom surface 34c2, and an outer circumferential surface 34c3. The inner circumferential surface 34c1 is a circumferential surface facing radially outward, located radially inward in the first annular groove 34c. The bottom surface 34c2 is a downward-facing annular plane. The outer circumferential surface 34c3 is a tapered surface facing radially inward, located radially outward in the first annular groove 34c, and its diameter increases as it moves away from the valve chamber 15. The inner circumferential surface 34c1 is connected to the first annular surface 34a. The outer circumferential surface 34c3 is connected to the third circumferential surface 35.

[0058] The valve seat member 11B, having a first annular groove 34c in the first connecting portion 34B, allows for a substantially reduced reduction in the volume inside the third circumferential surface 35, while increasing the length L2 of the second circumferential surface 33 in the axial direction K, compared to a configuration without the first annular groove 34c. As a result, the refrigerant can be effectively rectified on the second circumferential surface 33.

[0059] The valve seat member 11C shown in Figure 8 is provided with a valve opening 30C. The valve opening 30C has a first circumferential surface 31, a first tapered surface 32, a second circumferential surface 33, a first connecting portion 34, a third circumferential surface 35, a second connecting portion 36C, and a second tapered surface 37, which are connected in order from the valve seat 16 side in the direction of the axis K.

[0060] The second connecting portion 36C has a second annular surface 36a and a second annular groove 36c. The second annular groove 36c surrounds the second annular surface 36a. The second annular groove 36c has an inner circumferential surface 36c1, a bottom surface 36c2, and an outer circumferential surface 36c3. The inner circumferential surface 36c1 is a circumferential surface facing radially outward, located closer to the radially inward side of the second annular groove 36c. The bottom surface 36c2 is a downward-facing annular plane. The outer circumferential surface 36c3 is a tapered surface facing radially inward, located closer to the radially outward side of the second annular groove 36c, and its diameter increases as it moves away from the valve chamber 15. The inner circumferential surface 36c1 is connected to the second annular surface 36a. The outer circumferential surface 36c3 is connected to the second tapered surface 37 without any step.

[0061] The valve seat member 11C, having a second annular groove 36c in its second connecting portion 36C, allows for a longer length of the third circumferential surface 35 in the axial direction K, while substantially suppressing the reduction in the volume inside the second tapered surface 37, compared to a configuration without the second annular groove 36c. As a result, the refrigerant can be effectively rectified on the third circumferential surface 35.

[0062] The valve seat member 11D shown in Figure 9 is provided with a valve opening 30D. The valve opening 30D has a first circumferential surface 31, a first tapered surface 32, a second circumferential surface 33, a first connecting portion 34B, a third circumferential surface 35, a second connecting portion 36C, and a second tapered surface 37, which are connected in order from the valve seat 16 side in the direction of the axis K. The valve seat member 11D has the same effect as the valve seat member 11B (first connecting portion 34B) and the valve seat member 11C (second connecting portion 36C).

[0063] The valve seat member 11E shown in Figure 10 is provided with a valve opening 30E. The valve opening 30E has a first circumferential surface 31, a first tapered surface 32, a second circumferential surface 33, a first connecting portion 34E, a third circumferential surface 35, a second connecting portion 36E, and a second tapered surface 37, which are connected in order from the valve seat 16 side in the direction of the axis K.

[0064] The first connecting portion 34E has a first annular groove 34e. The first annular groove 34e surrounds the second circumferential surface 33. The first annular groove 34e has an inner circumferential surface 34e1, a bottom surface 34e2, and an outer circumferential surface 34e3. The inner circumferential surface 34e1 is a tapered surface facing radially outward, located radially inward in the first annular groove 34e, and its diameter increases as it approaches the valve chamber 15. The bottom surface 34e2 is a downward-facing annular plane. The outer circumferential surface 34e3 is a tapered surface facing radially inward, located radially outward in the first annular groove 34e, and its diameter increases as it moves away from the valve chamber 15. The inner circumferential surface 34e1 is connected to the second circumferential surface 33. The inner circumferential surface 34e1 is the first annular surface. The angle α between the axis K (i.e., the second circumferential surface 33) and the inner circumferential surface 34e1 is 45 degrees. The outer circumferential surface 34e3 is connected to the third circumferential surface 35.

[0065] The second connecting portion 36E has a second annular groove 36e. The second annular groove 36e surrounds the third circumferential surface 35. The second annular groove 36e has an inner circumferential surface 36e1, a bottom surface 36e2, and an outer circumferential surface 36e3. The inner circumferential surface 36e1 is a tapered surface facing radially outward, located radially inward in the second annular groove 36e, and its diameter increases as it approaches the valve chamber 15. The bottom surface 36e2 is a downward-facing annular plane. The outer circumferential surface 36e3 is a tapered surface facing radially inward, located radially outward in the second annular groove 36e, and its diameter increases as it moves away from the valve chamber 15. The inner circumferential surface 36e1 is connected to the third circumferential surface 35. The inner circumferential surface 36e1 is the second annular surface. The angle β between the axis K (i.e., the third circumferential surface 35) and the inner circumferential surface 36e1 is 45 degrees. The outer circumferential surface 36e3 is connected to the second tapered surface 37 without any step.

[0066] The valve seat member 11E performs the same function and effect as the valve seat member 11D.

[0067] Valve seat members 11A to 11E perform the same function and effect as valve seat member 11.

[0068] In this specification, terms indicating shapes such as "cylinder" and "column" are also used to refer to members or parts of members that substantially have the shape of those terms. For example, "cylindrical member" includes both cylindrical members and substantially cylindrical members. Furthermore, in this specification, the term "same" may include both strictly identical and substantially identical items.

[0069] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, deletions, design modifications, and combinations of features of the embodiments, as appropriate by those skilled in the art, are also included within the scope of the present invention, as long as they do not contradict the spirit of the invention. [Explanation of Symbols]

[0070] 1...Electric valve, 10...Valve body, 15...Valve chamber, 16...Valve seat, 18...Case component, 40...valve body, 50...can, 60...guide stem, 70...valve shaft, 78...coupling mechanism 80...Magnetic rotor, 90...Stator, 100...Motor 11, 11A... Valve seat member, 12... Base, 13... Peripheral wall, 14... Cylindrical part, K... Axis, 30... valve opening, 31...First surface, 32...First tapered surface, 33...Second surface, 34...First connecting portion, 34a...First annular surface, 34b...Intermediate tapered surface 35...Third circumferential surface, 36...Second connecting portion, 36a...Second annular surface, 37...Second tapered surface

Claims

1. A valve body assembly comprising a valve body provided with a valve chamber and a valve opening, and a valve element positioned in the valve chamber and facing the valve opening, The valve opening is located along the axis from the valve chamber side, The first surface and, A first tapered surface connected to the first circumferential surface, the diameter of which increases as it moves away from the valve chamber, A second circumferential surface having a larger diameter than the first circumferential surface is connected to the first tapered surface, The first connecting portion connected to the second circumferential surface, A third circumferential surface having a larger diameter than the second circumferential surface is connected to the first connecting portion, The second connecting portion connected to the third circumferential surface, It has a second tapered surface connected to the second connecting portion, the diameter of which increases as it moves away from the valve chamber, The first connecting portion has a first annular surface whose inner edge is connected to the second circumferential surface, The second connecting portion has a second annular surface whose inner edge is connected to the third circumferential surface, The angle between the axis and the first annular surface is 90 degrees or less. A valve body assembly characterized in that the angle between the axis and the second annular surface is 90 degrees or less.

2. The valve body assembly according to claim 1, wherein the first connecting portion has a first annular groove surrounding the first annular surface.

3. The valve body assembly according to claim 1, wherein the second connecting portion has a second annular groove surrounding the second annular surface.

4. The valve body assembly according to claim 1, wherein the first connecting portion has a first annular groove surrounding the second circumferential surface, and the inner circumferential surface of the first annular groove is the first annular surface.

5. The valve body assembly according to claim 1, wherein the second connecting portion has a second annular groove surrounding the third circumferential surface, and the inner circumferential surface of the second annular groove is the second annular surface.

6. The valve body assembly according to claim 1, wherein the diameter of the first circumferential surface is D1 and the diameter of the second circumferential surface is D2, and the following formula (1) is satisfied. (1) 1<D2 / D1<1.5

7. The valve body assembly according to claim 1, wherein when the diameter of the second circumferential surface is D2, the axial length of the second circumferential surface is L2, and the axial length of the portion of the valve opening that combines the first connection portion and the third circumferential surface is L3, the following equations (2) and (3) are satisfied. (2) L2 ≥ L3 (3) 5>(L2+L3) / D2≧2

8. An electric valve comprising a valve body assembly as described in claim 1 and a stator unit attached to the valve body assembly, The valve body assembly has a magnetic rotor, The stator unit has a stator, An electric valve in which the magnetic rotor and the stator constitute a motor for moving the valve body.

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