Flow path switching valve

Abstract

To provide a flow path switching valve capable of reliably bringing a plunger into contact with a fixed iron core, despite of having a simple structure.SOLUTION: A flow path switching valve 100 according to the present invention comprises a solenoid part 102 and a valve part 104. The solenoid part has: a plunger 108 that moves integrally with a shaft 106; a coil 110 that moves the plunger; a first fixed iron core 112 and a second fixed iron core 114 arranged at both ends of a stroke of the plunger; and a magnet 116 that attracts and holds the plunger to the first fixed iron core and the second fixed iron core at both ends of the stroke. The valve part has: a sleeve 120 having an input port 126 and multiple output ports 128, 130; and a spool 122 that is connected to the shaft of the solenoid part and slides inside the sleeve to switch the multiple output ports. When the plunger abuts against either the first fixed iron core or the second fixed iron core, the spool does not reach the stroke end of the spool.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a flow path switching valve including an electromagnetic portion and a valve portion. [Background technology]

[0002] As an example, the valve portion of a flow path switching valve includes a sleeve having at least an input port and an output port, and a spool slidably disposed inside the sleeve. When the coil of the electromagnetic part attached to the valve portion is excited, an attractive force is generated, and this attractive force displaces the spool to switch the flow path.

[0003] Patent Document 1 describes a solenoid valve having an electromagnetic part and a valve part. The electromagnetic part has a plunger, a fixed core (fixed iron core), a permanent magnet, a return spring (in the direction in which the plunger protrudes), and a coil part. The valve part has a body having an output port, another body having an input port and an output port, a valve stem, a valve seat, and a return spring (in the direction in which the plunger retracts).

[0004] In this solenoid valve, when the coil is energized, the plunger is held in close contact with the fixed core, and is pushed by the spring in the valve section to move the valve stem, opening the output port in the other body. When de-energized, the permanent magnet in the solenoid section maintains the plunger in close contact with the fixed core. When energized (polarity reversal), the magnetic force of the permanent magnet decreases, so the plunger cannot maintain close contact with the fixed core, and the spring in the solenoid section pushes the valve stem in the valve section, causing the valve seat to open the output port in the body. The valve stem is separate from the plunger, and is positioned by a support arm connected to the body and the other body, ensuring its central alignment with the plunger. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-217465 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the solenoid valve of Patent Document 1, the plunger and valve stem are separated. Although the plunger fits tightly against the fixed core, two return springs are required, making the structure complex. The solenoid valve is also a latching solenoid that holds the plunger at one end. This means the plunger must move against the spring in the valve unit, reducing plunger thrust. Furthermore, a support arm connected to a body and another body is required to position the valve stem, which is separated from the plunger, reducing the opening area of ​​the flow path.

[0007] In view of the above problems, an object of the present invention is to provide a flow path switching valve that has a simple structure and yet can reliably bring the plunger into contact with the fixed iron core. [Means for solving the problem]

[0008] In order to solve the above problems, a representative configuration of a flow path switching valve according to the present invention is a flow path switching valve equipped with an electromagnetic unit and a valve unit, wherein the electromagnetic unit has a plunger that moves integrally with the shaft, a coil that moves the plunger, two fixed iron cores arranged at both ends of the plunger's stroke, and magnets that attract and hold the plunger to the two fixed iron cores at both ends of the stroke, and the valve unit has a sleeve that has an input port and multiple output ports, and a spool that is connected to the shaft of the electromagnetic unit and slides inside the sleeve to switch between the multiple output ports, and is characterized in that when the plunger abuts against either of the two fixed iron cores, the spool does not reach the end of its stroke.

[0009] It is preferable that the spool has a through hole at its center that passes through from one end of the spool to the other end. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a flow path switching valve that has a simple structure and yet can reliably bring the plunger into contact with the fixed iron core. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an overall configuration diagram of a flow path switching valve according to an embodiment of the present invention; [Figure 2] 2 is a perspective view showing a part of an electromagnetic part and a spool of the flow path switching valve of FIG. 1. FIG. [Figure 3] 1. FIG. 4 is a diagram showing a process in which the shaft of the electromagnetic part of the flow path switching valve of FIG. 1 moves to the protruding side. [Figure 4] 2 is a diagram showing a state in which the shaft of the electromagnetic part of the flow path switching valve of FIG. 1 is held on the protruding side. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0013] 1 is an overall configuration diagram of a flow path switching valve 100 according to an embodiment of the present invention. The flow path switching valve 100 includes an electromagnetic unit 102 and a valve unit 104. The electromagnetic unit 102 includes a shaft 106, a plunger 108, a coil 110, a first stationary core 112, a second stationary core 114, a magnet 116, and a body (case 118).

[0014] Plunger 108 is a so-called movable iron core, and is configured integrally with shaft 106. When coil 110 is energized and becomes excited, plunger 108 is attracted to coil 110 and moves within case 118 together with shaft 106.

[0015] When the coil 110 (sometimes called a solenoid) is energized, it generates a magnetic field. Although it appears that there are two coils 110, the windings are connected, so it is actually "one divided coil."

[0016] The first fixed core 112 and the second fixed core 114 are each disposed inside the coil 110. The first fixed core 112 and the second fixed core 114 are disposed at both ends of the stroke (movement range) of the plunger 108, on the protruding side (left side in the drawing) of the shaft 106 and on the retracting side (right side in the drawing) of the shaft 106, respectively.

[0017] The magnet 116 is a permanent magnet that generates a magnetic flux that attracts and holds the plunger 108 to the first stator core 112 and the second stator core 114 at both ends of the stroke.

[0018] The figure illustrates the electromagnetic part 102 when the shaft 106 is retracted. At this time, magnetic flux M1 of the magnet 116 passes through the plunger 108, the second fixed core 114, and the case 118 and returns to the magnet 116. This causes the plunger 108 to be attracted to the second fixed core 114, and the retracted state of the shaft 106 is maintained. In addition, the electromagnetic part 102 has a magnetic gap (stroke of the plunger 108) of dimension La as shown in the figure.

[0019] The valve section 104 has a sleeve 120 and a spool 122 slidably supported inside the sleeve 120. The sleeve 120 is a hollow cylinder with a closed bottom and one end 124 closed, and is formed with one input port 126 and multiple (here, two) output ports 128 and 130. The sleeve 120 also has a small diameter section 131 formed between the output ports 128 and 130.

[0020] Furthermore, the sleeve 120 has a radially extending flange 132. The flange 132 of the sleeve 120 is attached to the electromagnetic part 102 in abutment against a wall part 134 of the electromagnetic part 102.

[0021] The spool 122 slides inside the sleeve 120 to switch between a plurality of output ports 128, 130. A through hole 142 is provided in the center of the spool 122, penetrating from one end 138 to the other end 140 of the spool 122.

[0022] Two pressure chambers 144, 146 are defined inside the sleeve 120. The pressure chamber 144 is defined by one end 124 of the sleeve 120 and one end 138 of the spool 122, and is a space in which a fluid such as hydraulic oil accumulates. As shown in the figure, the pressure chamber 144 has a distance of dimension Lb (end face distance: stroke of the spool 122) between one end 124 of the sleeve 120 and one end 138 of the spool 122. In the flow path switching valve 100, the dimension Lb of the end face distance (stroke of the spool 122) is greater than the dimension La of the stroke of the plunger 108.

[0023] The pressure chamber 146 is a space defined by a land 148 on the other end 140 side (electromagnetic section 102 side) of the spool 122 and a diaphragm 150 attached to the wall section 134 of the electromagnetic section 102. The spool 122 also has other lands 152 and 154, with the input port 126 of the sleeve 120 located between the lands 152 and 154.

[0024] Furthermore, the shaft 106 of the electromagnetic part 102 has a protruding tip 156 that penetrates the case 118, the wall part 134, and the diaphragm 150, and is further connected to the other end 140 of the spool 122. Therefore, the spool 122 of the valve part 104 can move together with the shaft 106 of the electromagnetic part 102.

[0025] In the flow path switching valve 100, when the shaft 106 of the electromagnetic part 102 is retracted and held on the retracted side as shown in the figure, a gap 158 is formed between the small diameter part 131 of the sleeve 120 and the land 152 of the spool 122. Therefore, in the flow path switching valve 100, the fluid supplied from the input port 126 passes through the gap 158 and is output from the output port 128.

[0026] Fig. 2 is a perspective view showing a portion of the electromagnetic part 102 and the spool 122 of the flow path switching valve 100 of Fig. 1. A large diameter part (potbelly 160) is provided at the tip 156 on the protruding side of the shaft 106 of the electromagnetic part 102. In addition, a locking groove 162 is formed at the other end 140 of the spool 122.

[0027] In the flow path switching valve 100 , the potbelly 160 at the tip 156 of the shaft 106 is locked by the locking groove 162 in the other end 140 of the spool 122 , so that the tip 156 of the shaft 106 is connected to the other end 140 of the spool 122 .

[0028] As shown, the through hole 142 of the spool 122 is connected to the locking groove 162 at the other end 140 of the spool 122. Furthermore, the locking groove 162 is partially cut out so that it can accommodate and lock onto the potbelly 160 at the tip 156 of the shaft 106. As a result, fluid that has accumulated in the pressure chamber 144 (see FIG. 1) on one end 138 of the spool 122 flows through the through hole 142 and further from the cut-out portion of the locking groove 162 to the pressure chamber 146 on the other end 140 of the spool 122 shown in FIG. 1.

[0029] Therefore, in the flow path switching valve 100, the through-hole 142 in the spool 122 allows fluid to flow between the pressure chambers 144, 146 at both ends of the spool 122. Therefore, the movement of the spool 122 is not hindered by the pressure of the fluid accumulated in the two pressure chambers 144, 146. Furthermore, the pressure difference between the two pressure chambers 144, 146 is reduced and substantially balanced. Strictly speaking, a slight difference in the area of ​​the pressure-receiving surface occurs by the cross-sectional area of ​​the portion that engages with the daruma 160, generating a force in the retracting direction. However, because this force is small, when the plunger 108 is held in the extended position by the magnet 116, there is no risk of the plunger 108 being retracted against this holding force.

[0030] 3 is a diagram showing a process in which the shaft 106 of the electromagnetic part 102 of the flow path switching valve 100 of FIG. 1 moves to the protruding side. In the flow path switching valve 100, when current is applied to the coil 110, a magnetic flux M2 is generated in a direction that cancels out the magnetic flux M1 (see FIG. 1) of the magnet 116. Therefore, on the second stationary core 114 side, the magnetic flux M1 of the magnet 116 is weakened by the magnetic flux M2 of the coil 110, and the attractive force between the plunger 108 and the second stationary core 114 decreases.

[0031] On the other hand, on the first fixed core 112 side, magnetic flux M2 of coil 110 passes through plunger 108, first fixed core 112, and case 118. This generates an attractive force between plunger 108 and first fixed core 112, causing plunger 108 and shaft 106 to move to the protruding side (left side in the drawing) as indicated by arrow A.

[0032] As the shaft 106 of the electromagnetic unit 102 moves toward the protruding side, the spool 122 of the valve unit 104 also moves. When the spool 122 moves, fluid flows from the pressure chamber 144 to the pressure chamber 146 via the through-hole 142 of the spool 122, and the pressures in the two pressure chambers 144, 146 are balanced. This allows the spool 122 to move reliably. As shown in the figure, the gap 158 (see FIG. 1) between the small diameter portion 131 of the sleeve 120 and the land 152 of the spool 122 is closed by the land 152.

[0033] Here, the dimension Lc of the width of the small diameter portion 131 of the sleeve 120 (the width of the output ports 128, 130) is larger than the dimension Ld of the width between the lands 152, 154 of the spool 122. Therefore, in the flow path switching valve 100, during the transitional period when the spool 122 is moving as shown in FIG. 3, the output port 128 and the output port 130 do not communicate with each other, so that the flow path can be switched reliably.

[0034] Fig. 4 is a diagram showing a state in which the shaft 106 of the electromagnetic part 102 of the flow path switching valve 100 of Fig. 1 is held on the protruding side. In the flow path switching valve 100, when the plunger 108 abuts against the first fixed iron core 112, the magnetic flux M3 of the magnet 116 passes through the plunger 108, the first fixed iron core 112, and the case 118 and returns to the magnet 116.

[0035] As a result, in the flow path switching valve 100, the plunger 108 is attracted to the first fixed core 112, and the protruding state of the shaft 106 is maintained. When the shaft 106 is to be retracted, the state shown in Fig. 4 can be transitioned to the state shown in Fig. 1 by energizing the coil 110 in the direction opposite to that shown in Fig. 3.

[0036] 4, in the flow path switching valve 100, when the shaft 106 of the electromagnetic part 102 is protruding and held on the protruding side, a gap 164 is formed between the small diameter part 131 of the sleeve 120 and the land 154 of the spool 122. Therefore, in the flow path switching valve 100, the fluid supplied from the input port 126 passes through the gap 164 and is output from the output port 130.

[0037] Furthermore, in the flow path switching valve 100, as described above, the dimension Lb of the end face distance between one end 124 of the sleeve 120 and one end 138 of the spool 122 (the stroke of the spool 122) is larger than the dimension La of the magnetic gap (the stroke of the plunger 108) of the electromagnetic part 102 shown in FIG.

[0038] 4, even when the plunger 108 is attracted to the first fixed core 112 and the shaft 106 is held on the protruding side, the one end 138 of the spool 122 is separated from the one end 124 of the sleeve 120. In other words, the one end 138 of the spool 122 does not reach the stroke end of the spool 122.

[0039] 1, even when the plunger 108 is attracted to the second fixed core 114 and held on the retracted side of the shaft 106, the other end 140 of the spool 122 is spaced apart from the diaphragm 150 attached to the wall portion 134 of the electromagnetic portion 102. In other words, the other end 140 of the spool 122 does not reach the stroke end of the spool 122.

[0040] As described above, with the flow path switching valve 100 according to this embodiment, the magnetic flux of the magnet 116 can attract and hold the plunger 108 in both directions, eliminating the need for a return spring. This simplifies the structure and prevents the plunger thrust from being impaired by the spring. Furthermore, because the flow path switching valve 100 is a spool type rather than a poppet type, it does not require a support arm or the like for positioning the valve stem as in a poppet type, and the opening area of ​​the flow path is not reduced.

[0041] Furthermore, in flow path switching valve 100, when plunger 101 abuts against either first fixed core 112 or second fixed core 114 at both ends of the stroke of plunger 108, spool 122 does not reach the stroke end. Therefore, flow path switching valve 100 allows plunger 108 to reliably abut against first fixed core 112 and second fixed core 114, and the maximum holding force of magnet 116 can be obtained.

[0042] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0043] The present invention can be used as a flow path switching valve having a sleeve in which a plurality of ports are formed. [Explanation of symbols]

[0044] 100...flow path switching valve, 102...electromagnetic part, 104...valve part, 106...shaft, 108...plunger, 110...coil, 112...first fixed iron core, 114...second fixed iron core, 116...magnet, 118...case, 120...sleeve, 122...spool, 124...one end of sleeve, 126...input port, 128, 130...output port, 131...small diameter part of sleeve, 132...flange of sleeve, 134...wall part of electromagnetic part, 138...one end of spool, 140...other end of spool, 142...through hole of spool, 144, 146...pressure chamber, 148, 152, 154...land of spool, 150...diaphragm, 156...tip of shaft, 158, 164...gap, 160...potamus, 162...locking groove

Claims

1. A flow path switching valve including an electromagnetic portion and a valve portion, The electromagnetic part is a plunger that moves integrally with the shaft; a coil for moving the plunger; Two fixed cores arranged at both ends of the stroke of the plunger; a magnet that attracts and holds the plunger to the two fixed iron cores at both ends of the stroke, The valve portion is a sleeve having an input port and a plurality of output ports; a spool connected to the shaft of the electromagnetic unit and sliding inside the sleeve to switch between the plurality of output ports; A flow path switching valve, characterized in that when the plunger abuts against either of the two fixed iron cores, the spool does not reach the stroke end of the spool.

2. 2. The flow path switching valve according to claim 1, wherein a through hole is provided in the center of the spool, passing through the spool from one end to the other end.

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