Small-power electromagnetic valve capable of improving sealing performance

Abstract

A low-power electromagnetic valve capable of improving sealing performance comprises a valve body provided with a water inlet, a water outlet and a valve seat communicated with the water inlet and the water outlet, the valve seat is in an annular shape formed by injection molding, and the axial opening end of the valve seat is an annular sealing end; the coil assembly is assembled and connected with the valve body and is electrically connected with an external power supply; the opening and closing piece acts along the axis of the valve seat to connect or disconnect the water inlet and the water outlet in response to power-on and power-off of the coil assembly, and is in contact with the sealing end to form a sealing surface; an annular protrusion is arranged on the end portion of the sealing end in the circumferential direction, the section of the annular protrusion is in an arc shape, an annular sinking table with the width b being equal to (0.05-0.3) mm is arranged on the sealing end in the mode of surrounding the inner circumference and / or the outer circumference of the valve seat, the height difference a between the lowest position of the sinking table and the highest position of the annular protrusion is equal to (0.05-0.3) mm, and the annular protrusion used for sealing is full in injection molding and good in sealing performance.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of electromagnetic valve, especially need to promote the sealing performance of low power electromagnetic valve, IPC classification belongs to F16K25 / 00. BACKGROUND

[0002] The water inlet electromagnetic valve in the automatic washing machine is the application typical of the low power electromagnetic valve, and it functions to turn on and off the water source. Since the water has a certain pressure when working, it can be designed into a no stuffing box type pilot operated electromagnetic valve, and the currently widely used structure mainly consists of two parts, the upper part is the pilot valve, and the lower part is the valve body. When the winding is not powered, the movable iron core falls due to the weight and the counterforce of the return spring, the pilot hole is closed, the water in the upper cavity of the valve membrane entering from the balance hole cannot be discharged, due to the different effective pressure bearing areas of the upper and lower surfaces of the valve membrane, the pressure difference formed makes the valve membrane press tightly on the valve seat, and the valve is closed. When the winding is powered, the electromagnetic attraction attracts the movable iron core to rise, and the water in the upper cavity of the valve membrane is discharged to the outlet of the valve through the pilot hole. Since the flow capacity of the pilot hole is designed to be much larger than that of the balance hole, the water flow generates a large enough pressure loss on the balance hole, the pressure in the upper cavity of the valve membrane drops sharply, and the pressure in the lower cavity of the valve membrane maintains the same as the pressure of the inlet, so that the pressure difference between the upper and lower surfaces of the valve membrane makes the valve membrane swell upward, the valve is opened, and the water flow is conducted. In addition, there is a small input power direct-acting electromagnetic valve, and the valve plug at one end of the valve seat is directly driven by the electromagnet.

[0003] The valve of the above-mentioned conventional design low power electromagnetic valve realizes the closing through the pressure difference between the upper and lower surfaces of the opening and closing element (valve membrane or valve plug), the pressure is usually not large, when the water pressure is low, the sealing property between the opening and closing element and the valve seat becomes poor, the existing design valve body is prone to injection not full, glue defect which cannot be visually and tactilely detected due to the gas trapping of the mold during the injection molding process, which leads to the further poor sealing property of the valve body and the opening and closing element. The unstable quality causes a considerable proportion of low water pressure leakage defects in some production batches.

[0004] For the relevant terms and knowledge, refer to《Low-voltage Electrical Apparatus Design Manual》(Mechanical Industry Press 1992 1st edition),《Valve Manual-Selection》(Chemical Industry Press 2013 1st edition),《IEC Electrical and Electronic Standard Terminology Dictionary》(China Standard Press 1992 1st edition),《Electrical Manufacturing Technology》(Mechanical Industry Press 1982 1st edition),《Mechanical Engineering Handbook》and《Electrical Engineering Handbook》(Mechanical Industry Press 1978 1st edition and 1997 2nd edition), GB14536.9《Special Requirements (Including Mechanical Requirements) for Electric Automatic Controllers and Electric Water Valves for Household and Similar Use》, GB / T21465-2008《Valve Terms》, QB / T 1291《Automatic Washing Machine Water Inlet Solenoid Valve》, CN213088786U《An electromagnetic valve with improved sealing performance》, CN215059850U《Electromagnetic valve pipe sealing structure and electromagnetic valve》. Utility model content

[0005] The utility model aims at, in order to solve the technical problem of low water pressure leakage of background art, provide a kind of small power electromagnetic valve of improving sealing performance and being convenient for manufacturing.The electromagnetic valve includes:

[0006] With water inlet, water outlet and the valve seat of the communication water inlet and water outlet, the valve seat is the annular of injection molding, and its axial opening end is annular sealing end;

[0007] With valve body assembly connection, and with the electric connection of external power supply coil assembly;

[0008] Response coil assembly on-off electricity and along the valve seat axis action to communicate or cut off water inlet and water outlet opening and closing piece, and the sealing surface is formed by the contact of sealing end;

[0009] Its characterized in that,

[0010] The end of sealing end is arranged as annular protrusion around the circumference, the cross-sectional shape of the annular protrusion is arc, and the annular sink of width b=(0.05-0.3)mm is arranged around the inner periphery and / or outer periphery of sealing end, and the height difference a=(0.05-0.3)mm between the lowest point of the sink and the highest point of the annular protrusion.

[0011] According to this special design, the injection mold can be designed as a splice part set along the inner and / or outer circumference of the annular valve seat. The splice seam extends upward from the annular countersunk platform along the inner and / or outer circumference of the valve seat. In the injection molding production of the valve body, when the molten plastic flows from the bottom to the top of the mold cavity of the annular valve seat, it first fills the valve seat protrusion and forms a full shape, and then fills along the cavity wall toward the annular countersunk platform. At the same time, air is expelled and discharged along the splice seam, so that the parting surface and weld line are located on the inner side and / or outer side of the annular countersunk platform near the inner circumference of the annular valve seat. This process can completely remove all air from the cavity, making it easy to fully inject the annular protrusion used for sealing, thus achieving good sealing performance. Even if the annular recess formed in the final stage is not full or has slight burrs or weld lines on its inner and outer parting surfaces, the height difference of a = (0.05-0.3) mm will not affect the seal due to the design. The width of the annular recess is set to b = (0.05-0.3) mm, so the mold assembly will not form sharp protrusions, resulting in high strength and resistance to breakage, making it easy to manufacture.

[0012] For solenoid valves with an input power of no more than 10W, the annular countersink should be designed with a height difference of a = (0.05-0.15)mm and a width of b = (0.05-0.15)mm. This can further enhance the strength of the corresponding mold assembly, reduce the risk of breakage, and make it easier for air in the mold cavity to be discharged during injection molding. The annular protrusion is formed more fully, and the defect rate is further reduced. The overflow and burrs on the inner side of the annular platform located on the parting surface are unlikely to exceed 0.05mm in height. Even if they do, they can be detected by visual inspection and touch inspection and will not be mixed into qualified products.

[0013] Preferably, the annular recess is designed as a plane to further enhance the strength of the corresponding mold assembly.

[0014] Preferably, the annular protrusion has an arc-shaped transition towards the annular recess, so that the molten plastic can be filled smoothly during injection molding, and the annular protrusion can be formed more fully. Attached Figure Description

[0015] Figure 1 This is a cross-sectional schematic diagram of the solenoid valve in Example 1;

[0016] Figure 2 yes Figure 1 Enlarged view of region A in the middle;

[0017] Figure 3 This is a cross-sectional schematic diagram of the valve body in Example 1;

[0018] Figure 4 This is a cross-sectional view of the valve seat and the corresponding mold core of the valve body in the separated state in Example 1;

[0019] Figure 5 yes Figure 4 Enlarged schematic diagram of region B in the middle.

[0020] Reference signs:

[0021] Valve body 10, valve cavity 11, water inlet 12, water outlet 13, valve seat 14, sealing end 141, annular protrusion 1411, annular sunken 1412, arc-shaped transition 1413, cylindrical core 60, ring column core 70, bottom end surface 71, split seam 80;

[0022] Coil assembly 20, winding 22;

[0023] Opening and closing element 30, valve film 31, inner ring part 313, through hole 311, balance hole 314, support frame 32, pilot hole 321, movable iron core 40, rubber plug 41. DETAILED DESCRIPTION

[0024] The embodiment of the utility model is the further improvement of the prior application CN213088786U of the inventor team of the application, and only the shape and size of the sealing end of the valve seat are improved, wherein the flow-through hole in CN213088786U is called a pilot hole according to "Valve Handbook - Selection". The technical scheme in the embodiment of the utility model will be described clearly and completely in combination with the drawings. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the scope of protection of the utility model.

[0025] The utility model only improves the shape and size of the sealing end of the valve seat of the existing electromagnetic valve, and the basic structure and working principle of the electromagnetic valve belong to the common knowledge in the art, and Chinese patent document CN213088786U, CN215059850U have respectively explained the pilot type electromagnetic valve and the direct acting type electromagnetic valve, and the utility model inherits the related structure and working principle thereof, and the present specification will not be repeated.

[0026] The "center", "upper", "lower", "inner", "outer" in the description are based on the orientation or positional relationship shown in Figure 1 , 4 The center line in Figure 1 , 4 is the center axis of the valve seat 14 of the valve body, that is, the center, the coil assembly is located above the valve body, and the ring column core is located above the valve seat.

[0027] Embodiment 1

[0028] As shown in Figure 1 , the utility model provides an electromagnetic valve for improving sealing performance, which comprises a valve body 10, a coil assembly 20, and an opening and closing element 30, a movable iron core 40.

[0029] As Figures 2-5 shown, the valve body 10 is made by injection molding of plastic, in the shape of a shell, with an internal cavity forming a valve chamber 11. The edge of the opening of the valve chamber 11 is provided with internal threads for threaded connection with the coil assembly 20. The bottom of the valve chamber 11 is provided with a water inlet 12, which is in communication with a water inlet pipe. The bottom of the valve chamber 11 is provided with a water outlet 13, which is in communication with a water outlet pipe. The water outlet 13 is provided with a circular annular rim around the opening of the valve chamber 11, forming a valve seat 14, with the opening end of the valve seat 14 being a circular annular sealing end 141, for abutting contact with the opening and closing member 30, to cut off the communication between the water inlet 12 and the water outlet 13. The end of the sealing end 141 is provided with a circular annular protrusion 1411 around the circumference, with the cross section being arc-shaped. The sealing end 141 is provided with a circular annular depression 1412 around the inner circumference of the valve seat 14, with a width of b = (0.05-0.3) mm, and the lowest part of the circular annular depression 1412 is at a height difference a = (0.05-0.3) mm from the highest part of the circular annular protrusion 1411.

[0030] As Figures 4-5 shown, when designing the mold, the mold is designed to be split along the inner circumference of the circular annular valve seat 14, with a cylindrical core 60 inserted into the inner circumference of the circular annular valve seat 14, and a ring-shaped core 70 around the cylindrical core 60, to be split together, forming a split seam 80. The outer circumference of the cylindrical core 60 corresponds to the inner circumference of the circular annular valve seat 14, the bottom end face 71 of the ring-shaped core 70 corresponds to the sealing end 141 of the circular annular valve seat 14, and the split seam 80 extends upward along the inner circumference of the valve seat 14 from the circular annular depression 1412.

[0031] When the valve body is produced by injection molding, the molten plastic flows from the bottom of the mold cavity of the circular annular valve seat 14 to the bottom end face 71 of the ring-shaped core 70, first filling the circular annular protrusion 1411 part of the valve seat 14 to form a full shape, then filling towards the circular annular depression 1412 along the cavity wall, while driving the air upward along the split seam 80 to be discharged, so that the parting surface and the weld mark of the product are located on the inner side of the circular annular depression 1412 close to the inner circumference of the circular annular valve seat 14, and all air in the cavity can be completely discharged. The circular annular protrusion 1411 for sealing is easy to be injection molded full, achieving good sealing performance. The circular annular depression 1412 formed in the final stage is not full or has a slight burr or weld mark on the inner side of the parting surface, but due to the design of the height difference of not less than 0.05 mm, it will not affect the sealing. The width of the circular annular depression 1412 is not less than 0.05 mm, and the bottom end face 71 of the ring-shaped core 70 produced accordingly will not form a sharp protruding part, with high strength and not easy to break, thus being easy to manufacture.

[0032] As Figure 1As shown, one end of the coil assembly 20 is formed with an external thread by injection molding of plastic, for mating with an internal thread provided on the opening of the valve cavity 11, to achieve threaded connection of the valve body 10 and the coil assembly 20. The coil assembly 20 is the electromagnetic control part of the electromagnetic valve, and is internally provided with a winding 22 for driving the movable iron core 40 and the valve element 30 to act when energized.

[0033] As shown in Figure 1 and Figure 2 , the valve element 30 of the main valve includes a valve film 31 and a support frame 32 rigidly supporting the valve film 31. The valve film 31 is a ring-shaped rubber member, the outer ring portion of which is compressed between the coil assembly 20 and the valve body 10 due to their threaded connection, and the inner ring portion 313 of which is in surface contact with the sealing end 141 of the valve seat 14; the valve film 31 divides the valve cavity 11 into upper and lower cavities, and has a through hole 311 in the middle portion, with a balance hole 314 provided beside the through hole 311 to communicate the upper and lower cavities of the valve cavity 11; the support frame 32 seals the two ends of the through hole 311 in the middle portion of the valve film 31, and the inner ring portion 313 of the valve film 31 abuts against the support frame 32 away from the valve seat 14; the support frame 32 is provided with a pilot hole 321 in the middle portion to communicate the upper cavity of the valve cavity 11 and the water outlet 13. The movable iron core 40 with a rubber plug 41 is provided above the pilot hole 321, and is actuated to rise to open the pilot hole 321 when the winding 22 is energized, and is actuated to fall to block the pilot hole 321 when the winding 22 is not energized. The working principle of the electromagnetic valve is known in the art, and has been described in detail in the background art, which will not be repeated here.

[0034] When the electromagnetic valve is off, the support frame 32 and the valve film 31 are tightly pressed against the sealing end 141 of the valve seat due to water pressure, and the inner ring portion 313 of the valve film abuts against the sealing end 141 of the valve seat to form a sealing surface, and the two form a pair of sealing pairs, and the annular protrusion 1411 of the sealing end 141 directly participates in sealing, is injection molded full, and in addition, the cross section of the annular protrusion 1411 is arc-shaped, and the deformation amount of the contact surface of the corresponding inner ring portion 313 of the valve film is large, so that the sealing pair can maintain good sealing performance even at low water pressure, and is not prone to leakage, thereby improving the off reliability of the electromagnetic valve.

[0035] For an electromagnetic valve with an input power not greater than 10W, the width b is set to (0.05-0.15) mm, and the height difference a is set to (0.05-0.15) mm, which can further enhance the strength of the bottom of the ring-cylinder-shaped core 70, reduce the risk of breakage, and also make the air in the mold cavity more easily discharged during injection molding, the annular protrusion 1411 is more fully formed, and the rejection rate is further reduced, and the overflow and burrs inside the annular platform 1412 on the parting surface are difficult to exceed a height of 0.05 mm, even if they exceed, they can be detected by visual inspection and tactile inspection, and will not be mixed into qualified products.

[0036] Preferably, the annular protrusion 1411 is connected to the annular sink 1412 by an arc-shaped transition 1413, so that the molten plastic can flow smoothly during injection molding, and the annular protrusion 1411 can be shaped more fully.

[0037] Preferably, the annular sink 1412 is a flat surface, further enhancing the strength of the bottom of the ring-cylindrical core 70.

[0038] The sealing end 141 in the embodiment is an annular sink 1412 arranged around the inner periphery of the valve seat 14. In other embodiments, it can also be arranged around the outer periphery of the valve seat 14, or both the inner and outer peripheries. Correspondingly, the spliced seam 80 of the mold core extends upward from the annular sink 1412 along the outer periphery of the valve seat 14, which can completely drain all air in the corresponding valve seat cavity during injection molding, so that the annular protrusion 1411 can be easily filled during injection molding, and the sealing performance is good.

[0039] The movable iron core 40 and the opening and closing member 30 in Embodiment 1 are replaced by the movable iron core and the circular plate-shaped valve plug shown in FIGS. 47.2-51 on pages 47-68 of the 1st edition of "Electrical Machinery Engineering Handbook Volume 8" published by the Mechanical Industry Press in 1982, or the linkage-arranged iron core and flow channel sealing member described in CN215059850U, which can be applied to a direct-acting electromagnetic shut-off valve, and can also improve the sealing performance of the sealing pair composed of the valve plug or the flow channel sealing member and the sealing end of the valve seat when the water pressure is low, thereby improving the shut-off reliability of the valve.

[0040] Although the specific embodiments of the utility model have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and additions can be made to the embodiments without departing from the principles and purposes of the utility model, and the scope of the utility model is defined by the claims and their equivalents.

Claims

1. A low-power electromagnetic valve with improved sealing performance, comprising: a valve body (10) having a water inlet (12), a water outlet (13), and a valve seat (14) connecting the water inlet (12) and the water outlet (13), the valve seat (14) being an annular injection molding, and having an annular sealing end (141) at an axially open end thereof; a coil assembly (20) assembled with the valve body (10) and electrically connected with an external power source; an opening and closing member (30) responsive to the on-off of the coil assembly (20) to move along an axis of the valve seat (14) to connect or block the water inlet (12) and the water outlet (13), and having a sealing surface formed by contacting the sealing end (141); characterized in that: an end of the sealing end (141) is provided with an annular protrusion (1411) around a circumference thereof, the annular protrusion having an arc-shaped cross section, and the sealing end (141) is provided with an annular sink (1412) around an inner circumference and / or an outer circumference of the valve seat (14), the sink having a width b = (0.05-0.3) mm, and a height difference a = (0.05-0.3) mm between a lowest point of the sink and a highest point of the annular protrusion (1411).

2. The low power electromagnetic valve with improved sealing performance according to claim 1, characterized in that, The annular sink (1412) is planar.

3. The low power electromagnetic valve with improved sealing performance according to claim 1, characterized in that, The annular protrusion (1411) is provided with an arc-shaped transition (1413) towards the annular sink (1412).

4. The low power electromagnetic valve with improved sealing performance according to claim 1, characterized in that, The electromagnetic valve has an input power of not more than 10 W, the height difference a = (0.05-0.15) mm, and the width b = (0.05-0.15) mm.

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