Electric valve

Abstract

The utility model provides an electrically operated valve which comprises a valve body and a coil, the valve body comprises a valve seat assembly and a shell, the shell is fixedly connected with the valve seat assembly, the valve body comprises a magnetic rotor assembly, the magnetic rotor assembly comprises a magnetic rotor, the magnetic rotor is located in the shell and comprises ferrite materials, and the coil is arranged in the magnetic rotor assembly. The coil comprises a first stator shell and a second stator shell, the second stator shell is located below the first stator shell, and the magnetic rotor can axially move relative to the coil. The maximum axial distance H1 between the first stator shell and the second stator shell and the height H2 of the magnetic rotor meet the relational expression that H2 is larger than H1, H2 = H1 + t, and t is the distance between the bottom of the magnetic rotor and the bottom of the second stator shell when the electric valve is in a valve closing state.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigeration, and particularly relates to an electric valve. Background Art

[0002] Electric valves are usually applied in refrigeration systems. Their basic function is to output variable power according to system parameters and keep the opening degree of the valve at the required position to maintain the required liquid supply amount of the evaporator. At present, the electric valves applied in refrigeration systems usually consist of a coil assembled outside the valve body and a rotor inside the valve body to form a motor. During the working process, the valve needle inside the valve body is driven by the magnetic rotor to adjust the opening degree of the valve port. The magnetic rotor usually uses ferrite materials, and its height is often the same as or approximately the same as the height of the stator housing. In this way, during the working process of the electric valve, the magnetic rotor makes a lifting movement while rotating through the threaded cooperation of the screw rod and the nut. In this way, an axial relative displacement will occur between the magnetic rotor and the coil assembled outside the valve body, and a step-out problem may occur at a high excitation speed. Summary of the Utility Model

[0003] For this reason, the purpose of the utility model is to enable the electric valve to be used reliably at a high excitation speed without significantly increasing the cost. For this purpose, the following technical solutions are adopted:

[0004] An electric valve, comprising a valve body and a coil. The valve body comprises a valve seat assembly and a housing. The housing is fixedly connected with the valve seat assembly. The valve body comprises a magnetic rotor assembly. The magnetic rotor assembly comprises a magnetic rotor. The magnetic rotor is located inside the housing. The magnetic rotor comprises ferrite materials. The coil comprises a first stator housing and a second stator housing. The second stator housing is located relatively below the first stator housing. The magnetic rotor can axially displace relative to the coil. The maximum axial distance H1 between the first stator housing and the second stator housing and the height H2 of the magnetic rotor satisfy the relational expression: H2 > H1, and H2 = H1 + t, where t is the distance between the bottom of the magnetic rotor and the bottom of the second stator housing when the electric valve is in the closed valve state.

[0005] In the above technical solution, the height H2 of the magnetic rotor is set to be greater than the maximum axial distance H1 between the first stator housing and the second stator housing. After the magnetic rotor moves upward by a certain stroke, the overlapping height of the magnetic rotor and the stator housing in the axial direction is longer than that in the background art. In the case that the magnetic rotor still uses ferrite materials, it can still be used reliably at a high excitation speed. Brief Description of the Drawings

[0006] Figure 1 is a schematic diagram of the closed valve state of the electric valve according to an embodiment of the utility model;

[0007] Figure 2 is Figure 1 a partially enlarged schematic view;

[0008] Figure 3 is a partially sectional schematic view of the open valve state of an electric valve according to an embodiment of the present invention;

[0009] Figure 4 is a partially schematic view of the positional relationship between the magnetic rotor and the stator housing when an electric valve in the prior art is in the closed state;

[0010] Figure 5 is Figure 4 a partially schematic view of the positional relationship between the magnetic rotor and the stator housing when the electric valve is in the open state. Specific Embodiments

[0011] The following describes the specific embodiments of the present invention with reference to the accompanying drawings of the specification.

[0012] All descriptions of the embodiments of this specification are based on the content of the accompanying drawings of the specification. The upper, lower, inner, outer and other orientation terms in the text are all descriptions made with respect to the accompanying drawings of the specification, and their purpose is to more conveniently describe the present invention and should not be regarded as a limitation to the present invention.

[0013] Please refer to Figures 1 - 3 , Figure 1 is a schematic view of the closed valve state of an electric valve according to an embodiment of the present invention; Figure 2 is Figure 1 a partially enlarged schematic view; Figure 3 is a partially sectional schematic view of the open valve state of an electric valve according to an embodiment of the present invention. The electric valve includes a valve body 1 and a coil 2. The valve body 1 includes a valve seat assembly 11. The valve seat assembly 11 includes a valve core seat 111, a valve seat 112, and a first connecting pipe 113 and a second connecting pipe 114 connected to the valve seat 112. The valve seat 112 is generally in a cylindrical structure, with an opening at the bottom for cooperating with the valve core seat 111 and being fixedly connected by welding. The upper end of the valve seat 112 is fixedly connected to the housing 12. The housing 12 is generally in a cylindrical shape, cooperates with the valve seat 112 and is fixedly and hermetically connected. In this way, the housing 12 and the valve seat 112 generally enclose a relatively closed cavity (except for the parts communicating with the first connecting pipe 113 and the second connecting pipe 114).

[0014] The circumferential outer wall of the valve core seat 111 is provided with a plurality of refrigerant flow holes 1115, and the lower end is provided with a valve port portion 1113. Both the refrigerant flow holes 1115 and the valve port portion 1113 can be used for the flow of refrigerant. Among them, the refrigerant flow holes 1115 are always in a communicating state, while the valve port portion 1113 is gradually opened or gradually closed during the axial movement of the valve needle described below, so as to adjust the refrigerant flow rate passing through the valve port portion 1113. The valve core seat 111 has a cylindrical structure, and a first guiding portion 1111 is provided at the outer edge portion on the side away from the valve port. The first guiding portion 1111 is used to cooperate with the nut component described below, and the two can be in a transition, interference or small clearance fit, so that the valve core seat can provide guidance for the nut during installation, which is beneficial to ensuring the coaxiality between the nut and the valve core seat. A second guiding portion 1112 is provided at the inner edge portion of the valve core seat 111. The second guiding portion 1112 is used to cooperate with the valve needle component described below, so that when the valve needle moves axially, the second guiding portion 1112 can guide the valve needle, which is beneficial to ensuring the coaxiality between the valve needle and the valve port. The valve core seat 111 can also be assembled in a split structure. For example, the cylindrical structure with the first guiding portion 1111 is taken as a single component, and the refrigerant flow holes 1115 are provided on this cylindrical structure; in addition, the part with the valve port 1113 is taken as another component, and then the two components are assembled, such as by a tight fit or welding method for fixed connection, so as to form the valve core seat 111.

[0015] The nut assembly includes a nut 21 and a connecting piece 22. The connecting piece 22 is integrally formed with the nut 21 as an insert. The connecting piece 22 is made of metal and is fixed to the valve seat 112 by welding. The nut 21 is a substantially annular structure composed of a plurality of stepped cylinders, and the material can be made of engineering resin. The inner hole of the nut has an internal thread section 216 for threaded cooperation with the lead screw. When processing the nut, the manufactured connecting piece 22 is placed in the mold, and the nut 21 is formed by injection molding, so that the connecting piece 22 is embedded in the nut 21 to form the nut assembly.

[0016] Inside the valve cavity of the electric valve, there is a lead screw 32 and a valve needle 35. The valve needle 35 moves up and down along the second guiding section 1112 of the valve core seat 111. The valve needle 35 has a blind hole with an upward opening. The front end of the valve needle 35 is a conical structure, and the rest of the valve needle 35 is a cylindrical structure. The conical front end moves up and down in the cavity of the valve core seat 11, approaching or departing from the valve port 1113 to control the opening degree of the valve port. The lead screw 32 and the valve needle 35 are connected in a floating manner, that is, they can move relative to each other axially and circumferentially, but will not be disengaged from each other as a whole. The lower end of the lead screw 32 is inserted into the blind hole of the valve needle. An external thread section 321 is provided on the circumferential surface of the lead screw 32, which is connected and matched with the internal thread section 216 of the nut 21. Therefore, the lead screw can rotate and move up and down relative to the nut 21. Moreover, the upper end of the lead screw 32 is fixedly connected to the magnetic rotor assembly. When the magnetic rotor assembly rotates, it drives the lead screw 32 to rotate, and through screw drive, the lead screw 32 moves up and down along the valve core seat 111. The lead screw 32 and the valve needle 35 can rotate relative to each other radially. In this way, when the lead screw 32 rotates with the rotation of the magnetic rotor, the valve needle 35 can remain stationary, which is more conducive to the stability of the lifting movement of the valve needle and more convenient to achieve precise control of the valve port opening degree.

[0017] The valve body 1 includes a magnetic rotor assembly. The magnetic rotor assembly is located inside the outer shell 12. The magnetic rotor assembly includes a magnetic rotor 42, a stop rod 41, and a connecting seat 43. The connecting seat 43 includes a substantially disk-shaped body. A boss-shaped lead screw mating part is provided in the middle of the body. A through hole is provided at the center position of the lead screw mating part for mating and fixedly connecting with the lead screw 32. A jack is also provided on the body for assembling the stop rod 41. The stop rod 41 and the connecting seat 43 can be fixed by welding. During manufacturing, the connecting seat 43 can be first placed in a mold, and the magnetic rotor 42 integrated with the connecting seat can be formed by injection molding. Then, the rod-shaped part of the stop rod 41 is inserted into the jack of the connecting seat 43, and the stop rod and the connecting seat are fixed by welding.

[0018] The stop assembly includes a spring guide rail 61 and a slip ring 62 that are nested inside and outside and are in spiral fit. The spring guide rail 61 is sleeved on the upper outer peripheral surface of the nut 21, and its lower end is embedded in the card slot on the outer periphery of the nut 21 for fixation, so as to keep relative limitation between the spring guide rail and the nut. The spring guide rail 61 can be made of a metal wire such as a steel wire wound. The slip ring 62 can slide along the spiral path defined by the spring guide rail 61. When the magnetic rotor 41 rotates, it can abut against the slip ring 62 and drive the slip ring 62 to rotate. The slip ring 62 can abut against the upper stop point and the lower stop point of the stop assembly, thereby determining the valve needle movement stroke of the electronic expansion valve.

[0019] Outside the housing 12 and the valve seat 112, a fixing frame 13 is also fixedly connected. The fixing frame 13 can be fixed to the housing 12 by laser welding, or can be fixed to the valve seat 112 by laser welding.

[0020] The coil 2 includes a pair of windings, namely the first winding 211 and the second winding 212. The first winding 211 is wound around the first bobbin 241, and the second winding 212 is wound around the second bobbin 242. The first stator housing 221 and the first electromagnetic pole plate 231 are combined and enclose the first winding 211 and the first bobbin 241 therein. Among them, the first stator housing 221 includes a first claw pole portion 2211. The first claw pole portion 2211 includes a plurality of claw poles located on the inner edge side of the bobbin. The first electromagnetic pole plate 231 includes a second claw pole portion 2311. The second claw pole portion 2311 also includes a plurality of claw poles located on the inner edge side of the bobbin. The first claw pole portion 2221 and the second claw pole portion 2311 are arranged alternately. Similarly, the second stator housing 222 and the second electromagnetic pole plate 232 are combined and enclose the second winding 212 and the second bobbin 242 therein. The second stator housing 222 includes a third claw pole portion 2221. The third claw pole portion 2221 includes a plurality of claw poles located on the inner edge side of the bobbin. The second electromagnetic pole plate 232 includes a fourth claw pole portion 2321. The fourth claw pole portion 2321 also includes a plurality of claw poles located on the inner edge side of the bobbin. The third claw pole portion 2221 and the fourth claw pole portion 2321 are arranged alternately. The combination formed by the first stator housing 221 and the first electromagnetic pole plate 231 is stacked with the combination formed by the second stator housing 222 and the second electromagnetic pole plate 232, that is, the first electromagnetic pole plate 231 abuts against the second electromagnetic pole plate 232. Then, the above components are encapsulated by injection molding to form an encapsulation body 25. When the electromagnetic coil is energized, it can generate a magnetic field, thereby driving the magnetic rotor to rotate. Specifically, the controller (not shown in the figure) energizes each winding in a certain order to control the rotation of the magnetic rotor, thereby driving the lead screw valve needle to move up and down in cooperation with the nut, so as to adjust the flow rate.

[0021] The coil 2 is located outside the housing 12, and the coil 2 and the magnetic rotor 42 are separated by the housing 12.

[0022] Define the maximum axial distance between the first stator housing and the second stator housing as H1. It can also be understood that the height of the claw pole is H1 (for the convenience of description, H1 will be described as the claw pole height in the following text). In common prior arts, please refer to Figure 4 、 Figure 5 , Figure 4 is a schematic diagram of the positional relationship between the magnetic rotor and the stator housing when an electric valve is in the closed state in the prior art; Figure 5 is Figure 4Schematic diagram of the positional relationship between the magnetic rotor and the stator housing when the electric valve is in the open state. The height of the magnetic rotor is H0, and H1 can be set to be the same as H1 or slightly less than H1, that is, H0 ≤ H1. Taking a specific electric valve as an example, the magnetic rotor is made of ferrite material, and the excitation speed is 30 - 40 PPS. The full stroke of the electric valve is 500 pulses. An excitation speed of 30 PPS means that the valve body rotates 30 pulses per second, that is, it takes 500 / 30 = 16.67 S for the valve body to move from the closed state to the fully open state. Since the rotor will displace axially relative to the valve body, assuming that when the electric valve is in the closed state, the claw pole height is H1 and the magnetic rotor height H0 is also close to H1. When the electric valve is opened and in the maximum opening position, the magnetic rotor rises by h relative to the claw pole height H1. At this time, in the cross-sectional height, the overlapping height between the magnetic rotor and the claw pole is H1 - h. It can also be understood that in this state, a part of the magnetic rotor protrudes above the upper surface of the claw pole in the axial direction. In the normal use scenario with an excitation speed of 30 - 40 PPS, it can be used normally. However, once the excitation speed exceeds this range, such as when using 83.3 PPS, there may be a step-out phenomenon. The step-out here refers to the magnetic rotor not reaching the specified number of steps and losing some pulse numbers during the movement process. The specific manifestation is that the magnetic rotor trembles and shakes and does not reach the specified position.

[0023]

[0024] In the above table, OK indicates normal use, and NG indicates the occurrence of a step-out phenomenon. From the above table, it can be seen that when a too high excitation speed is adopted, there is a risk of step-out.

[0025] To solve this technical problem and enable the magnetic rotor to operate reliably at a higher excitation speed, it is necessary to improve the magnetic performance of the magnetic rotor. A common approach is to change the magnetic rotor material to a rare earth material rotor, such as a neodymium iron boron rotor. The rare earth material rotor has higher magnetic performance and can operate at a higher excitation speed. However, its material cost is much higher than that of the ferrite rotor, which is not conducive to cost control and mass production.

[0026] The technical solution provided by this application aims to enable the magnetic rotor to adapt to a higher excitation speed and not easily have a step-out phenomenon without changing the magnetic rotor material of ferrite.

[0027] As Figure 2 shown, define the maximum axial distance between the first stator housing and the second stator housing as H1, which can also be understood as the height of the claw pole is H1, the height of the magnetic rotor 42 is H2, the top of the magnetic rotor 42 is flush with the top of the first stator housing 221, or the top of the magnetic rotor 42 is slightly lower than the top of the first stator housing 221, as Figure 2In the state shown, the top of the magnetic rotor 42 can be lower than the top of the first stator housing 221 by a height of x, where the value of x can be x ≤ 0.17h. In a common specification electric valve, the value of x can be set to 0 - 0.5 mm. There is a predetermined height difference t between the bottom of the magnetic rotor 42 and the bottom of the second stator housing 222. It can be understood that when the top of the magnetic rotor is flush with the top of the first stator housing, H2 = H1 + t, and when the top of the magnetic rotor is lower than the top of the first stator housing by X, H2 = H1 + t - x.

[0028] When the electric valve operates from the fully closed state to the fully open state, the magnetic rotor 42 is displaced upward by h, or in other words, the relative height position with respect to the claw pole moves by h. In this application, the value of t is set to 0.15h ≤ t < h. Then, in terms of the sectional height, the overlapping height of the magnetic rotor and the claw pole is H2 - h. In this way, compared with H1 - h in the prior art, the overlapping height of the magnetic rotor and the claw pole becomes longer. In this case, even if a rotor made of ferrite material is still used, it can still be reliably used at a high excitation speed.

[0029] The value of t can be set to 0.45 mm ≤ t < 3 mm. In a specific embodiment, it can be set to t = 2 mm = 0.67h, and the surface magnetic (mT) values are respectively - upper part: 112.3, middle part: 121, lower part: 127.4. A rotor out-of-step test is carried out:

[0030]

[0031] The test results show that even when the excitation speed is increased to 120 PPS, the electric valve can still work reliably without any out-of-step phenomenon. Therefore, this application can improve the reliability of the product at a relatively low cost.

[0032] The following combines Figure 1 , to illustrate the working principle of the electric valve:

[0033] Figure 1 It is a schematic diagram of the closed valve state of an electric valve according to an embodiment of the present invention. In this state, when the valve needs to be opened, the magnetic rotor 42 senses the electromagnetic force of the coil component and makes a rotational movement, causing the lead screw 32 to rotate accordingly. Since the lead screw 32 is in threaded engagement with the nut 21, in this way, while the lead screw rotates, it can also rise along the axial direction of the nut, thereby driving the valve needle 35 to gradually move away from the valve port 1113.

[0034] Taking the first connecting pipe 113 as the inlet pipe as an example, the refrigerant enters from the first connecting pipe 113, flows into the valve cavity, and passes through a number of refrigerant flow holes 1115 opened on the valve element seat 111. Then, it flows out of the second connecting pipe 14 through the gap between the valve needle 35 and the valve port 1113.

[0035] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.

Claims

1. Electric valve, comprising a valve body (1) and a coil (2), wherein the valve body (1) comprises a valve seat assembly (11) and a housing (12), the housing (12) is fixedly connected to the valve seat assembly (11), the valve body (1) comprises a magnetic rotor assembly, the magnetic rotor assembly comprises a magnetic rotor (42), the magnetic rotor is located inside the housing (12), the magnetic rotor (42) comprises a ferrite material, the coil (2) comprises a first stator housing (221) and a second stator housing (222), the second stator housing (222) is located relatively below the first stator housing (221), the magnetic rotor can undergo an axial displacement relative to the coil (2), and the maximum axial distance H1 between the first stator housing (221) and the second stator housing (222) and the height H2 of the magnetic rotor (42) satisfy the relation: H2 = H1 + t, where, t is the distance between the bottom of the magnetic rotor (42) and the bottom of the second stator housing (222) when the electric valve is in the valve-closed state.

2. The electric valve according to claim 1, characterized in that, Let the stroke of the axial displacement of the magnetic rotor (42) be h, then it satisfies: 0.15h ≤ t < h.

3. The electric valve according to claim 1, wherein The value range of the distance t between the bottom of the magnetic rotor (42) and the bottom of the second stator housing (222) is: 0.45 mm ≤ t < 3 mm.

4. The electric valve according to any one of claims 1-3, characterized in that, The coil (2) includes a first electromagnetic pole plate (231) and a second electromagnetic pole plate (232). The claw poles of the first electromagnetic pole plate (231) are arranged in an alternating manner with the claw poles of the first stator housing (221), and the claw poles of the second electromagnetic pole plate (232) are arranged in an alternating manner with the claw poles of the second stator housing (222).

5. Electric valve, comprising a valve body (1) and a coil (2), wherein the valve body (1) comprises a valve seat assembly (11) and a housing (12), the housing (12) is fixedly connected to the valve seat assembly (11), the valve body (1) comprises a magnetic rotor assembly, the magnetic rotor assembly comprises a magnetic rotor (42), the magnetic rotor is located inside the housing (12), the magnetic rotor (42) comprises a ferrite material, the coil (2) comprises a first stator housing (221) and a second stator housing (222), the second stator housing (222) is located relatively below the first stator housing (221), the magnetic rotor is capable of axially displacing relative to the coil (2), and the maximum axial distance H1 between the first stator housing (221) and the second stator housing (222) and the height H2 of the magnetic rotor (42) satisfy the relation: H2 = H1 + t - x, where, t is the distance between the bottom of the magnetic rotor (42) and the bottom of the second stator housing (222) when the electric valve is in the valve-closed state; x is the distance between the top of the magnetic rotor (42) and the top of the first stator housing (221) when the electric valve is in the valve-closed state.

6. The electric valve according to claim 5, characterized in that Let the stroke of the axial displacement of the magnetic rotor (42) be h, then it satisfies: 0.15h ≤ t < h.

7. The electric valve according to claim 6, wherein, The value of x is: x ≤ 0.17h.

8. The electric valve according to claim 7, characterized in that, The value of x is: x ≤ 0.5 mm.

9. The electric valve according to claim 5, characterized in that, The value range of the distance t between the bottom of the magnetic rotor (42) and the bottom of the second stator housing (222) is: 0.45 mm ≤ t < 3 mm.

10. The electric valve according to any one of claims 5-9, characterized in that, The coil (2) includes a first electromagnetic pole plate (231) and a second electromagnetic pole plate (232). The claw poles of the first electromagnetic pole plate (231) are arranged in an alternating manner with the claw poles of the first stator housing (221), and the claw poles of the second electromagnetic pole plate (232) are arranged in an alternating manner with the claw poles of the second stator housing (222).

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