Solenoid switching valve

Abstract

To provide a solenoid switching valve which can prevent a release of a hydraulic oil of an accumulator during a switching transition period of a switching valve, and maintain a pressure of a hydraulic oil at an A-port or a B-port during non-conduction period of the switching valve at low cost.SOLUTION: A solenoid switching valve according to the present invention includes: first and second non-leak three-way valves; and first and second pilot check valves having pushers which press a valve body to allow a backflow. A hydraulic pressure source is connected to pump ports of the first and second non-leak three-way valves. Tank ports of the first and second non-leak three-way valves are respectively connected to output ports of the first and second pilot check valves. The output ports of the first and second non-leak three-way valves are connected to external output ports while supplying pressure to pilot ports for operating the pushers of the first and second pilot check valves. Input ports of the first and second pilot check valves are connected to the tank ports.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic switching valve that controls the direction of hydraulic oil flow. [Background technology]

[0002] Electromagnetic switching valves are known as devices for controlling the supply of hydraulic oil in industrial facilities. For example, Patent Document 1 discloses a "hydraulic circuit for an actuator that includes an accumulator connected to a liquid supply means and an actuator connected to the accumulator via a switching valve." In Patent Document 1, "a non-leak three-way valve (poppet type electromagnetic valve) is provided between the accumulator and the switching valve (spool type electromagnetic valve)." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-278597 Summary of the Invention [Problem to be solved by the invention]

[0004] Not only in Patent Document 1, but generally, during a transitional period when a switching valve is switched, the P port, A port (or B port), and T port may momentarily become connected to each other. At this time, if an accumulator is located upstream of the switching valve, hydraulic oil is momentarily supplied to the actuator from the accumulator. In other words, when the switching valve momentarily becomes connected, hydraulic oil flows from the P port to the T port, and hydraulic oil accumulated in the accumulator is released. This leads to a decrease in efficiency of the entire circuit.

[0005] In the configuration of Patent Document 1, a non-leak three-way valve is disposed between the accumulator and the switching valve (upstream of the switching valve). According to Patent Document 1, the non-leak three-way valve blocks the accumulator from the switching valve, so even if an internal leakage occurs in the switching valve, oil will not be supplied from the accumulator to the switching valve. As a result, Patent Document 1 states that a pressure drop in the accumulator due to an internal leakage in the switching valve will not occur when the actuator is not operating.

[0006] However, because the switching valve in Patent Document 1 is a spool-type solenoid valve, it leaks, meaning it lacks a pressure-maintaining function. For this reason, a non-leak three-way valve is added to maintain pressure, but this increases the number of parts, which increases costs. It also requires controlling the opening and closing of the non-leak three-way valve in conjunction with the operation of the switching valve, which increases control costs. Furthermore, while the technology in Patent Document 1 can maintain the pressure in the accumulator (when the primary side is high pressure), it cannot maintain the pressure of the hydraulic oil at ports A and B (when the secondary side is high pressure) when the switching valve is not energized.

[0007] In view of these problems, the present invention aims to provide an electromagnetic switching valve that can prevent hydraulic oil from leaking from the accumulator during the switching transition period of the switching valve and can maintain the pressure of hydraulic oil at ports A and B at low cost when the switching valve is not energized. [Means for solving the problem]

[0008] In order to solve the above problems, a representative configuration of an electromagnetic switching valve according to the present invention comprises first and second non-leak three-way valves and first and second pilot check valves having pushers that push the valve bodies to allow reverse flow, a hydraulic source is connected to the pump ports (VP) of the first and second non-leak three-way valves, tank ports (VT) of the first and second non-leak three-way valves are connected to the output ports (OUT) of the first and second pilot check valves, respectively, the output ports (VA, VB) of the first and second non-leak three-way valves are connected to external output ports (A, B) while supplying pressure to a pilot port (PP1) that operates the pushers of the first and second pilot check valves, and the input ports (IN) of the first and second pilot check valves are connected to a tank port (T). [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an electromagnetic switching valve that can prevent hydraulic oil from leaking from the accumulator during the switching transition period of the switching valve and can maintain the pressure of hydraulic oil at ports A and B when the switching valve is not energized at low cost. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a hydraulic circuit including an electromagnetic switching valve according to an embodiment of the present invention. [Figure 2] 1 is a diagram illustrating a configuration of an electromagnetic switching valve according to an embodiment of the present invention. [Figure 3] 5A and 5B are diagrams illustrating the operation of the electromagnetic switching valve of the present embodiment. [Figure 4] 5A and 5B are diagrams illustrating the operation of the electromagnetic switching valve of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] Fig. 1 is a diagram illustrating a hydraulic circuit 200 including an electromagnetic switching valve 100 according to this embodiment. The hydraulic circuit 200 shown in Fig. 1 includes a pump 210, an accumulator 220, an actuator 230, and the electromagnetic switching valve 100 according to this embodiment.

[0013] The pump 210 is a hydraulic pressure source that supplies hydraulic oil to the electromagnetic switching valve 100 of this embodiment. An accumulator 220 is connected to a pump connection path 252 that connects the pump 210 and the P port of the electromagnetic switching valve 100. The accumulator 220 is disposed between the pump 210 and the electromagnetic switching valve 100, accumulates hydraulic oil at high pressure, and supplies the high-pressure hydraulic oil to the electromagnetic switching valve 100 as needed.

[0014] An actuator 230 to which hydraulic oil is supplied is connected to the electromagnetic switching valve 100. The actuator 230 includes a cylinder 232 and a piston 234. In this embodiment, a first connection path 254 connects an A port of the electromagnetic switching valve 100 to a first piston 234 chamber 236a of the cylinder 232 of the actuator 230. A second connection path 256 connects a B port of the electromagnetic switching valve 100 to a second piston chamber 236b of the cylinder 232 of the actuator 230.

[0015] Furthermore, the T port of the electromagnetic switching valve 100 is connected to the tank 240 by a tank path 258. This allows the working oil to be discharged from the electromagnetic switching valve 100 to the tank 240.

[0016] 2, 3, and 4 are diagrams illustrating the electromagnetic switching valve 100 of this embodiment. Fig. 2 illustrates the electromagnetic switching valve 100 in a non-energized state. As shown in Figs. 2 to 4, the electromagnetic switching valve 100 of this embodiment includes a main body 102, first and second non-leakage three-way valves (hereinafter referred to as the first three-way valve 110 and the second three-way valve 120), and first and second pilot check valves (hereinafter referred to as the first pilot check valve 130 and the second pilot check valve 140).

[0017] The first three-way valve 110 has a poppet 112, a sleeve 114, and a return spring 116. The poppet 112 is housed in the sleeve 114 and moves within the sleeve 114 when a first solenoid 150, which will be described later, is operated. The return spring 116 is disposed at the end of the sleeve 114 and biases the poppet 112 in a direction that pushes it back against the first solenoid 150.

[0018] The second three-way valve 120 has a poppet 122, a sleeve 124, and a return spring 126. The poppet 122 is housed in the sleeve 124 and moves within the sleeve 124 when a second solenoid 160, which will be described later, is operated. The return spring 126 is disposed at the end of the sleeve 124 and biases the poppet 122 in a direction that pushes it back against the second solenoid 160.

[0019] The first three-way valve 110 and the second three-way valve 120 are provided with a first solenoid 150 and a second solenoid 160, respectively, for operating them. That is, the first three-way valve 110 and the second three-way valve 120 are electromagnetic valves.

[0020] The first solenoid 150 is housed in a casing 152. A plunger 154 and a rod 156 are arranged inside the first solenoid 150. The second solenoid 160 is housed in a casing 162. A plunger 164 and a rod 166 are arranged inside the second solenoid 160.

[0021] The first pilot check valve 130 has a valve holder 132, a spring 134, a valve element 136, and a pusher 138. The valve holder 132 is fixed to the main body 102 of the solenoid switching valve 100, and holds the spring 134 inside. The spring 134 urges the valve element 136 toward the pusher 138. The pusher 138 is movable within the first pilot check valve 130 by hydraulic oil, and can push the valve element 136 to cause the hydraulic oil to flow backward.

[0022] The second pilot check valve 140 has a valve holder 142, a spring 144, a valve element 146, and a pusher 148. The valve holder 142 is fixed to the main body 102 of the solenoid switching valve 100, and holds the spring 144 inside. The spring 144 urges the valve element 146 toward the pusher 148. The pusher 148 is movable within the second pilot check valve 140 by the hydraulic oil, and can push the valve element 146 to cause the hydraulic oil to flow backward.

[0023] Next, the connection configuration of each port of the first three-way valve 110 and the second three-way valve 120 and each port of the first pilot check valve 130 and the second pilot check valve 140 in the electromagnetic switching valve 100 of this embodiment will be described.

[0024] A pump 210 (see FIG. 1) which is a hydraulic pressure source is connected to the pump port VP of each of the first three-way valve 110 and the second three-way valve 120 via a pump connection path 252.

[0025] The tank port VT of the first three-way valve 110 is connected to the output port OUT of the first pilot check valve 130. The tank port VT of the second three-way valve 120 is connected to the output port OUT of the second pilot check valve 140.

[0026] The output port VA of the first three-way valve 110 is connected to the pilot port PP1 of the second pilot check valve 140. The output port VB of the second three-way valve 120 is connected to the pilot port PP1 of the first pilot check valve .

[0027] The pilot port PP2 of the first pilot check valve 130 is connected to the external output port B. The pilot port PP2 of the second pilot check valve 140 is connected to the external output port A. The input port IN of the first pilot check valve 130 and the input port IN of the second pilot check valve 140 are connected to the tank port T.

[0028] That is, the output port VA of the first three-way valve 110 is connected to the external output port B while supplying pressure to the pilot port PP1 of the first pilot check valve 130. As a result, when hydraulic pressure is output from the first three-way valve 110, the pusher 138 operates, allowing backflow through the first pilot check valve 130. Similarly, the output port VB of the second three-way valve 120 is connected to the external output port A while supplying pressure to the pilot port PP1 of the second pilot check valve 140. As a result, when hydraulic pressure is output from the second three-way valve 120, the pusher 148 operates, allowing backflow through the second pilot check valve 140.

[0029] 2, when neither solenoid 150, 160 is energized, both pilot check valves 130, 140 function as check valves. Then, the pressure at external output port A passes through pilot ports PP2 and PP1 of second pilot check valve 140, and then through output port VA and tank port VT of first three-way valve 110 to be communicated with output port OUT of first pilot check valve 130, where the flow is stopped by first pilot check valve 130.

[0030] Similarly, the pressure applied to the external output port B passes through the pilot ports PP2 and PP1 of the first pilot check valve 130, the output port VB and the tank port VT of the second three-way valve 120, and reaches the output port OUT of the second pilot check valve 140, where the flow is stopped.

[0031] 3 is a diagram for explaining the operation of the solenoid switching valve 100 of this embodiment, illustrating a state in which the first solenoid 150 is energized and the second solenoid 160 is not energized. As shown in FIG. 3, when the first solenoid 150 is energized and excited, the plunger 154 moves and pushes the rod 156 toward the poppet 112. This moves the poppet 112 in the Y1 direction, and the pump port VP and output port VA of the first three-way valve 110 are connected to each other.

[0032] As a result, hydraulic oil from pump 210 flows in the direction F1 into pump port VP of first three-way valve 110. After passing through first three-way valve 110, hydraulic oil flows in the direction F2 from output port VA of first three-way valve 110 and flows into pilot port PP1 of second pilot check valve 140.

[0033] The hydraulic oil that has flowed into the second pilot check valve 140 passes through the external output port A in the direction F3 from the pilot port PP2 while urging the pusher 148 in the direction Y2 toward the valve body 146. The hydraulic oil is then supplied to the first piston chamber 236a of the cylinder 232 of the actuator 230 through the first connection path 254.

[0034] When hydraulic oil is supplied to the first piston chamber 236a of the cylinder 232, the piston 234 is pushed by the hydraulic oil, and the hydraulic oil in the second piston chamber 236b of the cylinder 232 is forced out in the direction F4 from the external output port B through the second connection path 256. The forced-out hydraulic oil flows in the direction F5, passing through the pilot port PP2 and pilot port PP1 of the first pilot check valve 130, and then flows into the output port VB of the second three-way valve 120.

[0035] At this time, the second three-way valve 120 is de-energized, so the output port VB and the tank port VT are in communication. Therefore, the hydraulic oil that has flowed into the output port VB of the second three-way valve 120 flows in the direction F6 from the tank port VT toward the second pilot check valve 140 and then into the output port OUT of the second pilot check valve 140.

[0036] As described above, in the second pilot check valve 140, the pusher 148 is urged in the Y2 direction toward the valve body 146 by the hydraulic oil that has flowed into the second pilot check valve 140. Therefore, the second pilot check valve 140 is in the open state. Therefore, the hydraulic oil that has flowed into the second pilot check valve 140 flows from the input port IN in the F7 direction and flows through the tank path 258 to the tank 240.

[0037] 4 is a diagram for explaining the operation of the solenoid switching valve 100 of this embodiment, illustrating a state in which the second solenoid 160 is energized and the first solenoid 150 is not energized. As shown in FIG. 4, when the second solenoid 160 is energized and excited, the plunger 164 moves and pushes the rod 166 toward the poppet 122. This causes the poppet 112 to move in the Y3 direction, and the pump port VP and output port VB of the second three-way valve 120 are connected to each other.

[0038] As a result, hydraulic oil from the pump 210 flows in the direction of F11 into the pump port VP of the second three-way valve 120. The hydraulic oil that has passed through the second three-way valve 120 flows in the direction of F12 from the output port VB of the second three-way valve 120 and flows into the pilot port PP1 of the first pilot check valve 130.

[0039] The hydraulic oil that has flowed into the first pilot check valve 130 passes through the external output port B in the direction F13 from the pilot port PP2 while urging the pusher 138 in the direction Y4 toward the valve body 136. The hydraulic oil is then supplied to the second piston chamber 236b of the cylinder 232 of the actuator 230 through the second connection path 256.

[0040] When hydraulic oil is supplied to the second piston chamber 236b of the cylinder 232, the piston 234 is pushed by the hydraulic oil, and the hydraulic oil in the first piston chamber 236a of the cylinder 232 is forced out from the external output port B in the direction F14 through the first connecting path 254. The forced-out hydraulic oil passes through the pilot port PP2 and pilot port PP1 of the second pilot check valve 140 and flows in the direction F15, and then flows into the output port VA of the first three-way valve 110.

[0041] At this time, the first three-way valve 110 is de-energized, so the output port VA and the tank port VT are connected. Therefore, the hydraulic oil that has flowed into the output port VA of the first three-way valve 110 flows from the tank port VT toward the first pilot check valve 130 in the direction F16, and then flows into the output port OUT of the first pilot check valve 130.

[0042] As described above, in the first pilot check valve 130, the pusher 138 is urged in the Y4 direction toward the valve element 136 by the hydraulic oil that has flowed into the first pilot check valve 130. Therefore, the first pilot check valve 130 is in the open state. Therefore, the hydraulic oil that has flowed into the first pilot check valve 130 flows from the input port IN in the F17 direction and flows through the tank path 258 to the tank 240.

[0043] As described above, according to the electromagnetic switching valve 100 of this embodiment, the tank ports (VT) of the first and second non-leak three-way valves 110, 120 are connected to the output ports (OUT) of the first and second pilot check valves 130, 140, respectively. As a result, when neither solenoid 150, 160 is energized, both pilot check valves 130, 140 function as check valves, and pressure can be maintained at the external output ports A, B.

[0044] By connecting the output ports (VA, VB) of the first and second non-leakage three-way valves 110, 120 to the pilot ports (PP1) of the first and second pilot check valves 130, 140, one of the pilot check valves 130 or 140 is allowed to reverse flow when the non-leakage three-way valves are operated. When the first three-way valve 110 operates, the second pilot check valve 140 is allowed to reverse flow, allowing the actuator 230 to operate. When the second three-way valve 120 operates, the first pilot check valve 130 is allowed to reverse flow, allowing the actuator 230 to operate in the reverse direction. This prevents hydraulic oil from leaking from the accumulator 220 due to pressure loss from ports A and B of the actuator 230 during a switching transition.

[0045] In this case, the only parts required are two simple non-leak three-way valves (first three-way valve 110 and second three-way valve 120) and two pilot check valves. This makes it possible to maintain pressure at port A and port B when the switching valve is not energized while minimizing the parts configuration, and it is possible to obtain the above-mentioned effects at low cost.

[0046] 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]

[0047] The present invention can be used as an electromagnetic switching valve that controls the direction of hydraulic oil flow. [Explanation of symbols]

[0048] 100... solenoid switching valve, 102... main body, 110... first three-way valve, 112... poppet, 114... sleeve, 116... return spring, 120... second three-way valve, 122... poppet, 124... sleeve, 126... return spring, 130... first pilot check valve, 132... valve holder, 134... spring, 136... valve disc, 138... pusher, 140... second pilot check valve, 142... valve holder, 144... spring, 146... valve disc, 148... pusher, 150... first solenoid, 152... casing, 154... plunger, 156... rod , 160...second solenoid, 200...hydraulic circuit, 210...pump, 220...accumulator, 230...actuator, 232...cylinder, 234...piston, 236a...first piston chamber, 236b...second piston chamber, 240...tank, 252...pump connection path, 254...first connection path, 256...second connection path, 258...tank path, A...output port, B...output port, IN...input port, OUT...output port, PP1, PP2...pilot port, T...tank port, VA...output port, VB...output port, VP...pump port, VT...tank port

Claims

[Claim 1] An electromagnetic switching valve, first and second non-leak three-way valves; a first pilot check valve and a second pilot check valve having a pusher for pushing the valve body to allow reverse flow; a hydraulic pressure source is connected to the pump ports of the first and second non-leak three-way valves; the tank ports of the first and second non-leak three-way valves are connected to the output ports of the first and second pilot check valves, respectively; output ports of the first and second non-leak three-way valves are connected to external output ports while supplying pressure to pilot ports that operate the pushers of the first and second pilot check valves; 1. An electromagnetic switching valve, wherein the input ports of the first and second pilot check valves are connected to a tank port.

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