Electromagnetic valve

Abstract

To provide an electromagnetic valve which can control a flow rate of a fluid accurately and does not limit a material of a core.SOLUTION: An electromagnetic valve 10 includes: a passage block 20 in which a fluid inflow passage 20a and a fluid outflow passage 20b are formed; a plunger 30 which opens or closes one of the fluid inflow passage 20a and the fluid outflow passage 20b; a diaphragm 50 which is provided at the opposite side of the passage block 20 across the plunger 30 and separates a housing chamber 40 which houses the plunger 30 from an external space; a fixed core 60 which is provided at the opposite side of the plunger 30 across the diaphragm 50 in the external space; a coil 70 provided at the radial outer side of the fixed core 60; and a case 80 which houses the fixed core 60 and the coil 70. The diaphragm 50 and the fixed core 60 are fixed by an adhesive 95.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a solenoid valve. [Background technology]

[0002] Patent Document 1 discloses an electromagnetic valve having a base in which an inlet and an outlet are formed, a valve head capable of closing the outlet, a diaphragm that surrounds the valve head to form an internal space, a core held in a case, and a solenoid that surrounds the core, with the core penetrating the diaphragm and its tip facing the valve head.

[0003] In the above solenoid valve, the core penetrates the diaphragm and faces the valve head, so the stroke of the valve head is determined only by the gap between the tip of the core and the valve head. Therefore, when used in applications where a pressure difference occurs between the inside and outside of the diaphragm, such as in semiconductor manufacturing processes, even if the diaphragm is deformed, the stroke of the valve head will not change, and the fluid flow rate can be accurately controlled. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-28737 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned solenoid valve, the core penetrates the diaphragm, so that the fluid flowing through the solenoid valve comes into contact with the core, and although the flow rate of the fluid can be accurately controlled, there is a problem in that the material of the core is limited to materials compatible with the fluid.

[0006] The present invention has been made in consideration of such technical problems, and has an object to provide a solenoid valve that can accurately control the fluid flow rate and is not limited by the material of the core. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided an solenoid valve comprising: a flow path block in which a fluid inlet flow path and a fluid outlet flow path are formed; a plunger which opens and closes one of the fluid inlet flow path and the fluid outlet flow path; a diaphragm which is provided on the opposite side of the flow path block across the plunger and which isolates a chamber in which the plunger is accommodated from an external space; a fixed core which is provided on the opposite side of the diaphragm across the plunger in the external space; a coil which is provided radially outside the fixed core; and a case which accommodates the fixed core and the coil, wherein the diaphragm and the fixed core are fixed with an adhesive. Effect of the Invention

[0008] According to the above aspect, since the diaphragm and the fixed core are fixed with an adhesive, even if a pressure difference occurs inside and outside the accommodating chamber, the rigidity of the fixed core suppresses deformation of the diaphragm. Therefore, the stroke of the plunger can be made constant, and the fluid flow rate can be accurately controlled. In addition, since the fixed core is provided in the external space, it does not come into contact with the fluid flowing through the accommodating chamber. Therefore, it is possible to avoid restrictions on the material of the fixed core depending on the type of fluid. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of a solenoid valve according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of a main portion of the solenoid valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a solenoid valve 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] Fig. 1 is a schematic cross-sectional view of a solenoid valve 10 according to an embodiment of the present invention. Fig. 2 is an enlarged view of a main portion of the solenoid valve 10. The up-down direction in Figs. 1 and 2 is the axial direction of the solenoid valve 10 (hereinafter simply referred to as the axial direction).

[0012] The solenoid valve 10 according to this embodiment is provided in a fluid control device used in, for example, semiconductor manufacturing. The fluid is, for example, a process gas.

[0013] 1, the solenoid valve 10 includes a flow path block 20 in which a fluid inflow flow path 20a and a fluid outflow flow path 20b are formed, a plunger 30 that opens and closes the fluid outflow flow path 20b, a diaphragm 50 that is provided on the opposite side of the flow path block 20 across the plunger 30 and isolates an accommodation chamber 40 (see FIG. 2) in which the plunger 30 is accommodated from an external space, a fixed core 60 that is provided on the opposite side of the diaphragm 50 across the plunger 30 in the external space, a coil 70 that is provided radially outside the fixed core 60, and a case 80 that accommodates the fixed core 60 and the coil 70. The fluid inflow flow path 20a, the fluid outflow flow path 20b, and the accommodation chamber 40 form a fluid flow path.

[0014] 1 and 2, the flow path block 20 has a fluid inflow flow path 20a, a fluid outflow flow path 20b, an annular valve seat 20c formed on the periphery of one end of the fluid outflow flow path 20b, an annular annular groove 20d formed around the valve seat 20c, and an annular mounting portion 20e formed around the annular groove 20d. One end of the fluid inflow flow path 20a opens to the bottom of the annular groove 20d.

[0015] When the plunger 30 is seated on the valve seat 20c, it closes one end of the fluid outlet passage 20b. This blocks communication between the fluid inflow passage 20a and the fluid outflow passage 20b. When the plunger 30 is separated from the valve seat 20c, it opens one end of the fluid outflow passage 20b. This allows communication between the fluid inflow passage 20a and the fluid outflow passage 20b.

[0016] The plunger 30 has a circular step 30a on the surface facing the flow path block 20. The step 30a has a diameter larger than that of the valve seat 20c, and an annular disc spring 31 is press-fitted and fixed onto the outer periphery thereof.

[0017] The mounting portion 20e has a disc spring 31, an annular diaphragm body 51, a disk-shaped diaphragm 50, an annular support ring 52, an annular first thrust plate 53, and an annular second thrust plate 54 stacked in this order, and is fastened to the flow path block 20 by nuts 90.

[0018] Specifically, the nut 90 has a retaining portion 90a and a female thread 90b, the flow path block 20 has a male thread 20f, and the male thread 20f and the female thread 90b are screwed together to fasten the nut 90 to the flow path block 20. As a result, the disc spring 31, the diaphragm body 51, the diaphragm 50, the support ring 52, the first thrust plate 53, and the second thrust plate 54 are retained between the retaining portion 90a and the mounting portion 20e.

[0019] The axial dimension of the diaphragm body 51 is set so that a gap is formed between the plunger 30 and the diaphragm 50 in the axial direction. The space including the gap is the accommodation chamber 40 that accommodates the plunger 30. The gap is, for example, about 0.05 mm to 0.2 mm.

[0020] The diaphragm body 51, the diaphragm 50, and the support ring 52 are integrated in advance by welding their outer peripheries. An annular gasket 55 is provided on the radial outside of the disc spring 31 and between the flow passage block 20 and the diaphragm body 51. The gasket 55 seals the gap between the flow passage block 20 and the diaphragm body 51. This isolates the accommodation chamber 40 from the external space.

[0021] The disk spring 31 has a plurality of through holes 31a formed therein, so that no pressure difference occurs between the fluid inflow passage 20a and the accommodation chamber 40.

[0022] The first thrust plate 53 and the second thrust plate 54 have a smaller coefficient of friction than other components (such as the diaphragm body 51) fastened by the nut 90. Therefore, slippage is likely to occur between the first thrust plate 53 and the second thrust plate 54 when the nut 90 is fastened. The first thrust plate 53 and the second thrust plate 54 may be the same part.

[0023] This prevents slippage between the flow path block 20 and the gasket 55, between the gasket 55 and the diaphragm body 51, etc. That is, when the nut 90 is fastened, it is possible to prevent the gasket 55, the diaphragm body 51, etc. from slipping and being scraped off, thereby preventing contamination. In addition, it is possible to prevent the members from rotating together.

[0024] The fixed core 60 is provided on the opposite side of the diaphragm 50 from the plunger 30 in the axial direction. In other words, the fixed core 60 is located in an external space separated from the accommodation chamber 40. The fixed core 60 is bonded and fixed to the diaphragm 50 with an adhesive 95.

[0025] The coil 70 is configured by winding a copper wire (not shown) around a bobbin 70a, and is disposed radially outside the fixed core 60.

[0026] The case 80 accommodates the fixed core 60 and the coil 70 inside, and is fastened to the flow passage block 20 with bolts (not shown).

[0027] The case 80 is provided with an electric wiring section 81 for supplying current to the coil 70 .

[0028] The solenoid valve 10 of this embodiment is configured as described above, and when a current is supplied to the coil 70, the magnetic field lines generated in the coil 70 pass through the fixed core 60, the diaphragm 50, the plunger 30, the diaphragm body 51, the nut 90, and the case 80 in this order, forming a loop of magnetic field lines. Note that the fixed core 60, the plunger 30, the diaphragm body 51, the nut 90, and the case 80 are made of magnetic materials, and the diaphragm 50 is made of a non-magnetic material.

[0029] When a magnetic force acts on the plunger 30, the plunger 30 is attracted to the fixed core 60 via the diaphragm 50, lifts off the valve seat 20c, and rises to a position where it is balanced with the spring force of the disc spring 31. This controls the flow rate of the fluid to a flow rate according to the current. The state where the plunger 30 abuts against the diaphragm 50 is the state where the flow rate of the fluid is maximum (the state where the flow rate is controlled to the maximum flow rate).

[0030] When the supply of current to the coil 70 is stopped, the spring force of the disc spring 31 causes the plunger 30 to seat on the valve seat 20c, and the fluid outflow passage 20b is closed.

[0031] Here, fluid control devices used in semiconductor manufacturing can create negative pressure within the system. Therefore, in a solenoid valve, if the space covered by the diaphragm (the plunger's housing) becomes negative pressure, the diaphragm may be distorted toward the housing chamber due to the internal and external pressure difference. If the diaphragm is distorted toward the housing chamber, the gap between the diaphragm and the plunger becomes smaller, reducing the range of motion of the plunger, making it impossible to control the maximum flow rate of the solenoid valve as desired.

[0032] To address this issue, it is possible to increase the thickness of the diaphragm to make it less likely to deform, or to use a structure in which the fixed core penetrates the diaphragm. However, because the diaphragm itself is a non-magnetic material, increasing the thickness of the diaphragm increases the magnetic resistance and weakens the attractive force of the plunger. Furthermore, in a structure in which the fixed core penetrates the diaphragm, the fluid flowing through the solenoid valve comes into contact with the fixed core, so the material of the fixed core is limited to materials that can handle the fluid.

[0033] In this regard, in this embodiment, the diaphragm 50 and the fixed core 60 are fixed with the adhesive 95, so that even if a pressure difference occurs inside and outside the accommodation chamber 40, the rigidity of the fixed core 60 suppresses deformation of the diaphragm 50. Therefore, the stroke (maximum stroke) of the plunger 30 can be made constant, so that the fluid flow rate (maximum flow rate) can be accurately controlled. In addition, since the fixed core 60 is provided in the external space, it does not come into contact with the fluid flowing through the accommodation chamber 40. Therefore, it is possible to avoid restrictions on the material of the fixed core 60 depending on the type of fluid.

[0034] It is preferable that the adhesive 95 is a magnetic adhesive, for example, an adhesive containing Ni filler.

[0035] When the adhesive 95 is a magnetic adhesive, the space between the diaphragm 50 and the fixed core 60 can be filled with a magnetic material, resulting in more stable magnetic characteristics.

[0036] In this embodiment, as described above, the case 80 and the fixed core 60 are separate bodies, and the fixed core 60 and the diaphragm 50 are bonded and fixed with the adhesive 95. However, the solenoid valve 10 may also be structured such that the case 80 and the fixed core 60 are formed as an integrated part.

[0037] However, when the case 80 and the fixed core 60 are formed as an integral part, there is a possibility that the gap between the diaphragm 50 and the fixed core 60 will become large due to dimensional variations in the axial direction. In this case, the magnetic resistance increases, and the attractive force of the plunger 30 becomes weak.

[0038] Furthermore, when the case 80 and the fixed core 60 are formed as an integral part, there is a possibility that the fixed core 60 will push the diaphragm 50 towards the plunger 30 due to dimensional variations in the axial direction. In this case, the gap between the diaphragm 50 and the plunger 30 will become smaller, reducing the range of motion of the plunger 30.

[0039] In this regard, in the solenoid valve 10 of the present embodiment, the fixed core 60 and the case 80 are separate bodies, and therefore the above-mentioned problems that may arise when the case 80 and the fixed core 60 are formed as an integrated part do not occur. Also, dimensional variations of each part can be tolerated more than when the case 80 and the fixed core 60 are formed as an integrated part.

[0040] Next, a method for assembling the solenoid valve 10 will be described.

[0041] In the first step, the gasket 55, the plunger 30, and the disc spring 31 are placed on the flow path block 20. The plunger 30 and the disc spring 31 are previously press-fitted and fixed.

[0042] In a second step, the diaphragm body 51, the diaphragm 50, the support ring 52, the first thrust plate 53, and the second thrust plate 54 are disposed on the gasket 55. Note that the diaphragm body 51, the diaphragm 50, and the support ring 52 are fixed by welding in advance.

[0043] In a third step, the nut 90 and the flow passage block 20 are fastened together.

[0044] In the fourth step, adhesive 95 is injected onto the upper surface of the diaphragm 50 .

[0045] In the fifth step, the fixed core 60 is disposed on the diaphragm 50 .

[0046] In a sixth step, the coil 70 and the case 80 are placed on the nuts 90 and fastened to the flow passage block 20 with bolts (not shown).

[0047] Since it is only necessary that the fixed core 60 be placed on and fixed to the diaphragm 50 before the adhesive 95 dries, the order of the fourth and fifth steps may be reversed.

[0048] Furthermore, adhesive 95 may or may not be interposed in the gap between the diaphragm 50 and the fixed core 60. The peripheral edge portion of the fixed core 60 and the upper surface portion of the diaphragm 50 may be bonded and fixed by the adhesive 95.

[0049] The main functions and effects of the solenoid valve 10 according to the embodiment of the present invention will be described below.

[0050] The solenoid valve 10 comprises a flow path block 20 in which a fluid inlet flow path 20a and a fluid outlet flow path 20b are formed, a plunger 30 that opens and closes the fluid outlet flow path 20b, a diaphragm 50 that is provided on the opposite side of the flow path block 20 across the plunger 30 and isolates a storage chamber 40 in which the plunger 30 is accommodated from an external space, a fixed core 60 that is provided on the opposite side of the diaphragm 50 in the external space from the plunger 30, a coil 70 that is provided radially outside the fixed core 60, and a case 80 that accommodates the fixed core 60 and the coil 70, and the diaphragm 50 and the fixed core 60 are fixed with an adhesive 95.

[0051] According to this, since the diaphragm 50 and the fixed core 60 are fixed with the adhesive 95, even if a pressure difference occurs inside and outside the accommodation chamber 40, the rigidity of the fixed core 60 suppresses deformation of the diaphragm 50. Therefore, the stroke (maximum stroke) of the plunger 30 can be made constant, so that the fluid flow rate (maximum flow rate) can be accurately controlled. In addition, since the fixed core 60 is provided in the external space, it does not come into contact with the fluid flowing through the accommodation chamber 40. Therefore, it is possible to avoid restrictions on the material of the fixed core 60 depending on the type of fluid.

[0052] The adhesive 95 may be a magnetic adhesive.

[0053] When the adhesive 95 is a magnetic adhesive, the space between the diaphragm 50 and the fixed core 60 can be filled with a magnetic material, resulting in more stable magnetic characteristics.

[0054] An embodiment of the present invention has been described above, but the above embodiment merely illustrates one application example of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment.

[0055] For example, the solenoid valve 10 of the above embodiment is configured so that the plunger 30 opens and closes the fluid outlet passage 20b. However, the plunger 30 may be configured so as to open and close the fluid inlet passage 20a.

[0056] In addition, the solenoid valve 10 of the above embodiment is configured such that the fluid inflow passage 20a opens to the annular groove 20d, and the fluid outflow passage 20b opens to the inside of the valve seat 20c. However, the fluid outflow passage 20b may be configured to open to the annular groove 20d, and the fluid inflow passage 20a may be configured to open to the inside of the valve seat 20c. [Explanation of symbols]

[0057] 10. Solenoid valve 20 Flow path block 20a Fluid inflow channel 20b Fluid outlet passage 30 Plunger 40 Containment Room 50 Diaphragm 60 fixed core 70 Coil 80 cases 95 Adhesive

Claims

1. a flow path block in which a fluid inflow flow path and a fluid outflow flow path are formed; a plunger for opening and closing one of the fluid inflow passage and the fluid outflow passage; a diaphragm that is provided on the opposite side of the flow path block with the plunger therebetween and isolates an accommodation chamber in which the plunger is accommodated from an external space; a fixed core provided on an opposite side of the plunger with the diaphragm interposed therebetween in the external space; A coil provided radially outside the fixed core; a case that accommodates the fixed core and the coil; Equipped with The diaphragm and the fixed core are fixed with an adhesive. Solenoid valve.

2. 2. The solenoid valve according to claim 1, The adhesive is a magnetic adhesive. Solenoid valve.

Images