solenoid valve

Abstract

To make a movable core easy to separate from a fixed core upon turning off of energization to a coil and achieve good responsibility by regulating face contact of one end face of the fixed iron core and one end of the movable iron core without adding a separate member.SOLUTION: An electromagnetic valve 1 comprises: a coil 2; a fixed core 3 outside of which the coil 2 is arranged; a movable core 4 opposing the fixed core 3 coaxially therewith so as to be capable of reciprocation; and a cylinder yoke 5 arranged at the fixed core 3 coaxially therewith and surrounding an external periphery of the movable core 4. The electromagnetic valve is configured so that the fixed core 3 sucks the movable core 4 in an axial direction with a magnetic force generated by the coil 2 in order to reciprocate the movable core 4. The movable core 4 has one end 4a, and the fixed core 3 has one end face 3a opposing the one end 4a of the movable core 4. The electromagnetic valve 1 further comprises abutment limiting means for limiting abutment of the one end 4a of the movable core 4 on the one end face 3a of the fixed core 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a solenoid valve configured such that a fixed core attracts a movable core in the axial direction by a magnetic force generated by a coil. [Background technology]

[0002] A known example of this type of technology is the "linear solenoid" described in Patent Document 1 listed below. This linear solenoid includes a housing, which houses a coil, a fixed core (fixed iron core) with the coil arranged on the outside, a cylindrical movable core (movable iron core) that is attracted to the fixed iron core when current is passed through the coil, and a cylindrical yoke that surrounds the outer periphery of the movable iron core. The fixed iron core has a recess that faces the movable iron core. A hole that is continuous with this recess has a first stopper member made of a non-magnetic material that restricts displacement of one side of the movable iron core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-77355 Summary of the Invention [Problem to be solved by the invention]

[0004] In the linear solenoid described in Patent Document 1, the displacement of the movable iron core is restricted by the first stopper member, so the fixed iron core and the movable iron core do not come into direct contact, and the movable iron core easily separates from the fixed iron core when the current to the coil is turned off. However, because this linear solenoid requires the addition of the first stopper member, component costs and manufacturing costs increase accordingly. While it is possible to omit the first stopper member, simply omitting the first stopper member would result in one end of the movable iron core coming into surface contact with one end surface of the fixed iron core, making it difficult for the movable iron core to separate from the fixed iron core when the current to the coil is turned off.

[0005] This disclosed technology has been made in consideration of the above circumstances, and its purpose is to provide a solenoid valve that, without adding any new components, restricts surface contact between one end face of the fixed core and one end of the movable core, thereby making it easier for the movable core to separate from the fixed core when power is turned off to the coil, thereby achieving good responsiveness. [Means for solving the problem]

[0006] In order to achieve the above object, the technology described in claim 1 comprises a coil that generates a magnetic force when energized, a fixed iron core on the outside of which the coil is arranged, a movable iron core that is coaxially opposed to the fixed iron core and capable of reciprocating, and a cylindrical yoke that is coaxially arranged with the fixed iron core and that is arranged to surround the outer periphery of the movable iron core. 、 In the solenoid valve, the fixed core is configured to attract the front movable core in the axial direction by a magnetic force generated by a coil to reciprocate the movable core, the movable core has one end in the axial direction, and the fixed core has one end face facing the one end of the movable core in the axial direction, A ring member made of a non-magnetic material that inhibits direct magnetic flux coupling is provided between the fixed core and the yoke, and the movable core includes a small outer diameter portion with a small outer diameter corresponding to one end thereof and a large outer diameter portion with a large outer diameter, and the minimum inner diameter of the ring member is smaller than the outer diameter of the large outer diameter portion of the movable core and larger than the outer diameter of the small outer diameter portion, so that when the coil generates magnetic force by passing current through it, the fixed core attracts the movable core in the axial direction, and the large outer diameter portion of the movable core abuts against the ring member, thereby limiting the abutment between one end of the movable core and one end face of the fixed core. The purpose of this is to

[0007] According to the configuration of the above technology, in the solenoid valve, the movable iron core faces the fixed iron core on the outside of which the coil is arranged so as to be capable of reciprocating coaxially. Also, a cylindrical yoke is arranged coaxially with the fixed iron core so as to surround the outer periphery of the movable iron core. The solenoid valve is configured so that the fixed iron core attracts the movable iron core in the axial direction by the magnetic force generated by the coil, in order to reciprocate the movable iron core. Here, The minimum inner diameter of the non-magnetic ring member provided between the fixed core and the yoke is smaller than the outer diameter of the large outer diameter portion of the movable core and larger than the outer diameter of the small outer diameter portion. When the coil is energized to generate magnetic force, the fixed core attracts the movable core in the axial direction, causing the large outer diameter portion of the movable core to abut against the ring member, thereby limiting the abutment between one end of the movable core and one end face of the fixed core. [Effects of the Invention]

[0016] According to the technology described in claim 1, it is possible to restrict the surface contact between one end face of the fixed iron core and one end of the movable iron core without adding any new components, making it possible to make the movable iron core more easily separate from the fixed iron core when the current to the coil is turned off, thereby obtaining good responsiveness for the movable iron core. Furthermore, even when the movable iron core comes into contact with the ring member, there is no magnetic force between them, which improves the responsiveness of the movable iron core. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 is a cross-sectional view showing the solenoid valve according to the first embodiment. [Figure 2] 2 is an enlarged cross-sectional view of the solenoid valve of FIG. 1 in the first embodiment, showing the vicinity of a ring member. [Figure 3] 2 is an enlarged cross-sectional view of the solenoid valve of FIG. 1 in the first embodiment, showing the vicinity of the valve seat. [Figure 4] FIG. 10 is a cross-sectional view showing a solenoid valve according to a second embodiment. [Figure 5] 5 is an enlarged cross-sectional view of the solenoid valve of FIG. 4 in the second embodiment, showing the vicinity of a ring member. [Figure 6] 5 is an enlarged cross-sectional view of the solenoid valve of FIG. 4 in the second embodiment, showing the vicinity of the valve seat. [Figure 7] FIG. 10 is a cross-sectional view showing a solenoid valve according to a third embodiment. [Figure 8] 8 is an enlarged cross-sectional view of the solenoid valve of FIG. 7 in the vicinity of a ring member according to a third embodiment. [Figure 9] 8 is an enlarged cross-sectional view of the solenoid valve of FIG. 7 in the vicinity of the valve seat according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] First Embodiment A first embodiment of a solenoid valve will be described in detail below with reference to the drawings.

[0023] [Solenoid valve configuration] 1 shows a cross-sectional view of a solenoid valve 1 of this embodiment. This solenoid valve 1 includes a coil 2 that generates a magnetic force when current is applied, a substantially cylindrical fixed core 3 around which the coil 2 is arranged, a substantially cylindrical movable core 4 that faces the fixed core 3 coaxially and is capable of reciprocating motion, and a cylindrical yoke 5 that is arranged coaxially with the fixed core 3 and surrounds the outer periphery of the movable core 4. The coil 2 is covered by a resin casing 6, and the outside of the casing 6 is covered by an outer yoke 7 made of a magnetic material. A power supply connector 8 is provided in a part of the casing 6.

[0024] The cylindrical yoke 5 has a bore 5a extending in its axial direction. A valve seat 9 is located at the lower end of the cylindrical yoke 5, facing the lower end of the movable core 4, which functions as a valve element, and on which the movable core 4 can be seated. The valve seat 9 has a valve hole 9a and is made of a non-magnetic material. The movable core 4 is made of a magnetic material and has one end 4a (upper end in Figure 1) in the axial direction, as well as a middle hole 4b and a tip hole 4c that penetrates from the middle hole 4b to the valve seat 9. The fixed core 3 is made of a magnetic material and has one end face 3a (lower side in Figure 1) that faces one end 4a of the movable core 4 in the axial direction, as well as a middle hole 3b that extends in the axial direction. A ring member 10 made of a non-magnetic material is provided between the fixed core 3 and the cylindrical yoke 5 to inhibit direct magnetic flux coupling. A spring 11 is provided between the upper end of the movable core 4 and the lower end of the fixed core 3, biasing the movable core 4 in a direction (valve closing direction) so that the movable core 4 seats on the valve seat 9. When current is applied to the coil 2, this solenoid valve 1 forms a magnetic circuit 16 between the members 3, 4, 5, and 7, as shown by the dashed lines in Figure 1.

[0025] This solenoid valve 1 is configured such that the fixed core 3 attracts the movable core 4 in the axial direction due to the magnetic force generated by the coil 2, causing the movable core 4 to reciprocate. That is, when the solenoid valve 1 is opened, the magnetic force generated by the coil 2 causes the fixed core 3 to attract the movable core 4 in the axial direction against the biasing force of the spring 11. As a result, the movable core 4, which functions as a valve body, moves away from the valve seat 9 (opening the valve), and the valve orifice 9a is opened. In this open state, the valve orifice 9a communicates with the central bore 4b of the movable core 4 and the central bore 3b of the fixed core 3, allowing fluid to flow through the flow path. When the solenoid valve 1 is closed, the generation of magnetic force by the coil 2 is stopped, and the attraction of the movable core 4 by the fixed core 3 is stopped. As a result, the biasing force of the spring 11 causes the movable core 4 to seat on the valve seat 9 (closing the valve), and the valve orifice 9a is closed. This solenoid valve 1 constitutes a linear solenoid in that it reciprocates the movable core 4 relative to the fixed core 3.

[0026] FIG. 2 is an enlarged cross-sectional view of the solenoid valve 1 of FIG. 1, showing the vicinity of the ring member 10. FIG. 3 is an enlarged cross-sectional view of the solenoid valve 1 of FIG. 1, showing the vicinity of the valve seat 9. In this embodiment, as shown in FIGS. 1 and 2, the movable core 4 includes a small outer diameter portion 4d and a large outer diameter portion 4e, each corresponding to one end 4a of the movable core 4. The ring member 10 has a convex cross-section and includes a small inner diameter portion 10a and a large inner diameter portion 10b, with a step between the small inner diameter portion 10a and the large inner diameter portion 10b. The upper end of the cylindrical yoke 5 and the lower end corresponding to one end face 3a of the fixed core 3 are fitted into this step. Here, the outer diameter of the cylindrical yoke 5 and the outer diameter of the ring member 10 are the same, but the inner diameter of the bore 5a of the cylindrical yoke 5 is larger than the minimum inner diameter Ds of the ring member 10. As a result, the thickness of the cylindrical yoke 5 is smaller than the thickness of the ring member 10.

[0027] 1 and 3, a non-magnetic sleeve 9b extending upward is formed integrally with the valve seat 9 near its outer periphery. This sleeve 9b is formed separately from the cylindrical yoke 5 in order to make the lower end of the cylindrical yoke 5 non-magnetic. In this embodiment, the sleeve 9b of the valve seat 9 is combined with the inside of the lower end of the cylindrical yoke 5. In this embodiment, the inner periphery of the sleeve 9b projects slightly toward the movable core 4 beyond the inner periphery of the cylindrical yoke 5, and the outer periphery of the movable core 4 is slidably supported by the sleeve 9b.

[0028] In this embodiment, strictly speaking, the outer periphery of the movable core 4 is in contact only with the small inner diameter portion 10a of the ring member 10 and the inner periphery of the sleeve 9b of the valve seat 9, but is not in contact with the inner periphery of the bore 5a of the cylindrical yoke 5. In other words, a minute gap is formed between the outer periphery of the movable core 4 and the inner periphery of the bore 5a of the cylindrical yoke 5.

[0029] [About contact restriction measures] In the solenoid valve 1 of this embodiment, if one end 4a of the movable core 4 comes into surface contact with one end face 3a of the fixed core 3, the movable core 4 will have difficulty separating from the fixed core 3 when the current to the coil 2 is turned off, which may result in poor responsiveness of the movable core 4. Therefore, the solenoid valve 1 of this embodiment is provided with a contact limiting means for limiting the contact between the one end face 3a of the fixed core 3 and the one end 4a of the movable core 4. In this embodiment, the contact limiting means is configured by setting the shapes of the fixed core 3, the movable core 4, and the cylindrical yoke 7.

[0030] In this embodiment, the minimum inner diameter Ds corresponding to the small inner diameter portion 10a of the ring member 10 is smaller than the outer diameter of the large outer diameter portion 4e of the movable core 4 and larger than the outer diameter of the small outer diameter portion 4d, which serves as a contact limiting means. As a result, a step surface 4f is formed between the small outer diameter portion 4d and the large outer diameter portion 4e of the movable core 4. In this embodiment, the small outer diameter portion 4d of the movable core 4 is slidably supported by the small inner diameter portion 10a of the ring member 10.

[0031] [About the action and effect of solenoid valves] According to the configuration of the solenoid valve 1 of this embodiment described above, in the solenoid valve 1, the movable core 4 faces the fixed core 3 on the outside of which the coil 2 is arranged so as to be able to reciprocate coaxially. Furthermore, the cylindrical yoke 5 is arranged coaxially with the fixed core 3 so as to surround the outer periphery of the movable core 4. The solenoid valve 1 is configured so that the fixed core 3 attracts the movable core 4 in the axial direction by the magnetic force generated by the coil 2, in order to reciprocate the movable core 4. Here, one end 4a of the movable core 4 and one end face 3a of the fixed core 3 face each other in the axial direction, but even if the fixed core 3 attracts the movable core 4 in the axial direction, the contact limiting means limits contact between the one end 4a of the movable core 4 and one end face 3a of the fixed core 3. Therefore, without adding any new components, it is possible to restrict the surface contact between one end face 3a of the fixed iron core 3 and one end 4a of the movable iron core 4, making it easier for the movable iron core 4 to separate from the fixed iron core 3 when the current to the coil 2 is turned off, and achieving good responsiveness for the movable iron core 4.

[0032] According to the configuration of this embodiment, the contact limiting means is a non-magnetic ring member 10 provided between the fixed core 3 and the cylindrical yoke 5, whose minimum inner diameter Ds is smaller than the outer diameter of the large outer diameter portion 4e of the movable core 4 and larger than the outer diameter of the small outer diameter portion 4d. As a result, a step surface 4f is formed between the small outer diameter portion 4d and the large outer diameter portion 4e of the movable core 4. Therefore, when the movable core 4 moves toward the fixed core 3, the step surface 4f comes into contact with the non-magnetic ring member 10, thereby restricting the movement of the movable core 4. Therefore, even when the movable core 4 comes into contact with the ring member 10, no magnetic force acts between them, thereby improving the responsiveness of the movable core 4.

[0033] Second Embodiment Next, a second embodiment of the solenoid valve will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment will be given the same reference numerals and will not be described again, and the following description will focus on the differences.

[0034] [About contact restriction measures] This embodiment differs from the first embodiment in the configuration of the contact limiting means. FIG. 4 shows a cross-sectional view of the solenoid valve 1 of this embodiment. FIG. 5 shows an enlarged cross-sectional view of the vicinity of the ring member 10 of the solenoid valve 1 of FIG. 4. FIG. 6 shows an enlarged cross-sectional view of the vicinity of the valve seat 9 of the solenoid valve 1 of FIG. 4. As shown in FIGS. 4 to 6, this embodiment differs from the first embodiment mainly in the configuration of the vicinity of the ring member 10. Here, the outer diameter of the cylindrical yoke 5 and the outer diameter of the ring member 10 are the same, and the inner diameter of the bore 5a of the cylindrical yoke 5 and the minimum inner diameter Ds of the ring member 10 are approximately the same. As a result, the thickness of the cylindrical yoke 5 is approximately the same as the thickness of the ring member 10.

[0035] In this embodiment, the fixed core 3 includes a large inner diameter portion 3c at one end corresponding to the end face 3a, the inner diameter of which is larger than the diameter of the outer edge of the end face 3a. Here, the "outer edge" of the end face 3a refers to the outer edge (the right side in FIG. 5) of the flat end face 3a shown in FIG. 5. The one end 4a of the movable core 4 has an outer diameter smaller than the inner diameter of the large inner diameter portion 3c of the fixed core 3 but larger than the diameter of the outer edge of the one end face 3a. Between the outer edge of the one end face 3a of the fixed core 3 and the large inner diameter portion 3c, an expanded-diameter inner surface 3d is provided, the inner diameter of which of the fixed core 3 expands toward the one end 4a of the movable core 4, and this serves as a contact limiting means. In this embodiment, the expanded-diameter inner surface 3d has a tapered shape. As the movable core 4 moves, its one end 4a can come into contact with the expanded-diameter inner surface 3d. In this embodiment, the large outer diameter portion 4e of the movable core 4 is slidably supported by the small inner diameter portion 10a of the ring member 10.

[0036] [About the action and effect of solenoid valves] The configuration of the solenoid valve 1 of this embodiment described above can achieve the same functions and effects as those of the first embodiment. Additionally, unlike the first embodiment, in this embodiment, the contact limiting means is an expanded-diameter inner surface 3d that is provided between the outer edge of one end face 3a of the fixed core 3 and the large inner-diameter portion 3c, and the inner diameter of the fixed core 3 expands toward one end 4a of the movable core. Therefore, when the movable core 4 moves toward the fixed core 3, one end 4a of the movable core 4 comes into contact with the expanded-diameter inner surface 3d of the fixed core 3, thereby restricting the movement of the movable core 4. Therefore, even if one end 4a of the movable core 4 comes into contact with the expanded-diameter inner surface 3d of the fixed core 3, both 4a and 3d are in line contact, ensuring good responsiveness of the movable core 4.

[0037] According to the configuration of this embodiment, it is relatively easy to form the tapered diameter-expanded inner surface 3d, which allows the manufacturing cost of the stator core 3 to be reduced.

[0038] Third Embodiment Next, a third embodiment of the solenoid valve will be described in detail with reference to the drawings.

[0039] [About contact restriction measures] This embodiment differs from the previous embodiments in the configuration of the contact limiting means. FIG. 7 shows a cross-sectional view of the solenoid valve 1 of this embodiment. FIG. 8 shows an enlarged cross-sectional view of the solenoid valve 1 of FIG. 7 near the ring member 10. FIG. 9 shows an enlarged cross-sectional view of the solenoid valve 1 of FIG. 7 near the valve seat 9. As shown in FIGS. 7 to 9, this embodiment differs from the second embodiment mainly in the configurations near the ring member 10 and the valve seat 9. Here, one end face 3a of the fixed core 3 is flat, but the expanded-diameter inner surface 3d of the second embodiment is not provided between the outer edge of the one end face 3a and the large inner diameter portion 3c. In addition, the outer diameter of the cylindrical yoke 5 and the outer diameter of the ring member 10 are the same, and the inner diameter of the bore 5a of the cylindrical yoke 5 and the minimum inner diameter Ds of the ring member 10 are approximately the same. As a result, the thickness of the cylindrical yoke 5 is approximately the same as the thickness of the ring member 10. In this embodiment, the thickness of the sleeve 9b of the valve seat 9 is smaller than the thickness of the sleeve 9b in the second embodiment, so that a step surface 5d of the cylindrical yoke 5 is exposed between the end edge of the bore 5a of the cylindrical yoke 5 and the sleeve 9b.

[0040] In this embodiment, the movable core 4 includes an end 4g on the opposite side of the one end 4a in the axial direction. The other end 4g includes a small outer diameter portion 4h and a large outer diameter portion 4i, both of which correspond to the other end 4g. The cylindrical yoke 5 also includes a small inner diameter portion 5b and a large inner diameter portion 5c, both of which correspond to the other end 4g of the movable core 4. The large outer diameter portion 4i of the movable core 4 has an outer diameter that is larger than the inner diameter of the small inner diameter portion 5b of the cylindrical yoke 5 but smaller than the inner diameter of the large inner diameter portion 5c of the cylindrical yoke 5, which serves as a contact limiting means. This forms a step surface 4j between the small outer diameter portion 4h and the large outer diameter portion 4i of the movable core 4, and a step surface 5d between the small inner diameter portion 5b and the large inner diameter portion 5c of the cylindrical yoke 5. In this embodiment, the step surface 4j of the movable core 4 has a tapered shape, and the step surface 5d of the cylindrical yoke 5 has a flat shape. In this embodiment, the large outer diameter portion 4i of the movable core 4 is slidably supported on the inner periphery of the sleeve 9b.

[0041] [About the action and effect of solenoid valves] The configuration of the solenoid valve 1 of this embodiment described above has the following effects and advantages, unlike the previous embodiments. That is, in this embodiment, the contact limiting means is a large outer diameter portion 4i that corresponds to the other end 4g opposite to one end 4a of the movable core 4 and has an outer diameter larger than that of the small outer diameter portion 4h, and that is larger than the inner diameter of the small inner diameter portion 5b of the cylindrical yoke 5 and smaller than the inner diameter of the large inner diameter portion 5c. As a result, a step surface 4j is formed between the small outer diameter portion 4h and the large outer diameter portion 4i of the movable core 4, and a step surface 5d is also formed between the small inner diameter portion 5b and the large inner diameter portion 5c of the cylindrical yoke 5. Therefore, when the movable core 4 moves toward the fixed core 3, the step surface 4j comes into contact with the step surface 5d of the cylindrical yoke 5 at the corresponding portion of the other end 4g of the movable core 4, thereby restricting the movement of the movable core 4. Therefore, there is no need to provide a contact limiting means between one end 4a of the movable iron core 4 and one end face 3a of the fixed iron core 3, so the closest distance between one end 4a of the movable iron core 4 and one end face 3a of the fixed iron core 3 can be optimized by taking advantage of the characteristics of magnetic force.

[0042] <Another embodiment> The disclosed technology is not limited to the above-described embodiments, and can be implemented by appropriately modifying part of the configuration within the scope of the disclosed technology.

[0043] (1) In the second embodiment, the expanded diameter inner surface 3d of the fixed core 3 is formed in a tapered shape, but this expanded diameter inner surface can also be formed in a curved shape.

[0044] (2) In the third embodiment, the step surface 4j of the movable core 4 is tapered and the step surface 5d of the cylindrical yoke 5 is flat. However, it is also possible to form the step surface of the movable core flat and the step surface of the cylindrical yoke tapered, or to form the step surfaces of the movable core and the cylindrical yoke flat.

[0045] (3) In each of the above embodiments, the solenoid valve 1 is provided with the valve seat 9 corresponding to the movable iron core 4 which functions as a valve body, but the present invention may also be embodied in a solenoid valve that does not have this valve seat. [Industrial Applicability]

[0046] The disclosed technology can be used in linear solenoid type electromagnetic valves used to control fluid flow rates. [Explanation of symbols]

[0047] 1 solenoid valve 2 coils 3 Fixed core 3a One end face 3c Large inner diameter part 3d Expanded inner surface 4 moving core 4a one end 4d Small outer diameter part 4e Large outer diameter part 4g other end 4h Small outer diameter part 4i Large outer diameter section 5 Cylindrical yoke 5b Small inner diameter part 5c Large inner diameter section 10 Ring member 10a Small inner diameter section Ds Minimum inner diameter (of ring member)

Claims

[Claim 1] A coil that generates magnetic force when energized; a fixed core on the outside of which the coil is disposed; a movable iron core that faces the fixed iron core coaxially and reciprocally; a cylindrical yoke that is arranged coaxially with the fixed core and surrounds the outer periphery of the movable core, In a solenoid valve configured such that the fixed core attracts the movable core in the axial direction by a magnetic force generated by the coil, in order to reciprocate the movable core, The movable core has one end in its axial direction, the fixed core has one end surface that faces the one end of the movable core in the axial direction, a ring member made of a non-magnetic material that inhibits direct magnetic flux coupling is provided between the fixed core and the yoke; the movable core includes a small outer diameter portion having a small outer diameter corresponding to one end thereof and a large outer diameter portion having a large outer diameter, a minimum inner diameter of the ring member is smaller than an outer diameter of the large outer diameter portion of the movable iron core and larger than an outer diameter of the small outer diameter portion; When the coil generates a magnetic force by energizing it, the fixed core attracts the movable core in the axial direction, and the large outer diameter portion of the movable core abuts against the ring member, thereby restricting the abutment between the one end of the movable core and the one end face of the fixed core. A solenoid valve characterized by:

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