Pilot type solenoid valve

Abstract

To provide a pilot type solenoid valve capable of determining whether a malfunction, in which a pilot valve cannot operate the spool of a main valve, is caused by either of the pilot valve and the main valve.SOLUTION: A pilot type solenoid valve of the present invention is configured to include a main valve that controls the direction in which hydraulic oil flows, a pilot valve that operates the main valve, and an abnormality determination unit that determines an abnormality in the operation of the main valve. The pilot valve has a spool, a solenoid, and a pilot valve-side switch that detects the neutral position and switching position of the pilot valve spool. The main valve has a spool, a solenoid, and a main valve-side switch that detects the neutral position and switching position of the main valve spool. The abnormality determination unit determines that there is an abnormality in the main valve when it detects from the outputs of the pilot valve-side switch and the main valve-side switch that the pilot valve spool is in the switching position and the main valve spool is in the neutral position.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pilot type solenoid valve including a main valve that controls the direction in which hydraulic oil flows, and a pilot valve that operates the main valve. [Background technology]

[0002] Pilot-type solenoid valves are known as devices for controlling the supply of hydraulic oil in industrial facilities. For example, Patent Document 1 discloses a "pilot-operated solenoid switching valve characterized by comprising a main valve spool that switches the connection of an oil passage by displacing according to the direction of pilot pressure acting on the end, a pilot solenoid valve that switches the direction of the pilot pressure acting on the end of the main valve spool by an electric signal, and an electromagnetic solenoid device that applies a mechanical displacement force to the end of the main valve spool regardless of the pilot pressure." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3166924 Summary of the Invention [Problem to be solved by the invention]

[0004] According to Patent Document 1, "when it is necessary to switch the main valve, if the required pilot pressure cannot be obtained by switching the electromagnetic pilot valve, the main valve spool can be mechanically moved as desired." However, with the technology of Patent Document 1, if the spool of the main valve cannot be switched by the electromagnetic pilot valve, it is not possible to determine whether the malfunction occurs in the electromagnetic pilot valve or the main valve. For this reason, there is room for further improvement in the technology of Patent Document 1.

[0005] In view of the above problems, the present invention aims to provide a pilot type solenoid valve that, when a malfunction occurs in which the pilot valve cannot operate the spool of the main valve, is capable of determining whether the malfunction is caused by the pilot valve or the main valve. [Means for solving the problem]

[0006] In order to solve the above problems, a typical configuration of a pilot type solenoid valve according to the present invention includes a main valve that controls the direction in which hydraulic oil flows, a pilot valve that operates the main valve, and an abnormality judgment unit that judges abnormality in the operation of the main valve, wherein the pilot valve has a spool, a solenoid that operates the spool of the pilot valve, and a pilot valve side switch that detects the neutral position and the switching position of the spool of the pilot valve, and the main valve has a spool that operates with the pressure of the pilot valve, a solenoid that forcibly operates the spool of the main valve, and a main valve side switch that detects the neutral position and the switching position of the spool of the main valve, and the abnormality judgment unit judges that there is an abnormality in the main valve when it detects from the outputs of the pilot valve side switch and the main valve side switch that the spool of the pilot valve is in the switching position and the spool of the main valve is in the neutral position.

[0007] If the abnormality determination unit detects that the pilot valve spool is operating but the main valve spool is not operating, it places the main valve solenoid in an energized state, and if it detects that the main valve solenoid is energized and the main valve spool is in a neutral position, it determines that there is an abnormality in the main valve. Effect of the Invention

[0008] According to the present invention, it is possible to provide a pilot type solenoid valve that, when a malfunction occurs in which the pilot valve cannot operate the spool of the main valve, is capable of determining whether the malfunction is caused by the pilot valve or the main valve. [Brief description of the drawings]

[0009] [Figure 1]1 is a diagram illustrating a pilot type solenoid valve according to an embodiment of the present invention. FIG. [Diagram 2] 4 is a schematic diagram illustrating a configuration of a first abnormality determination unit. FIG. [Diagram 3] 4 is a schematic diagram illustrating a configuration of a second abnormality determination unit. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0011] Fig. 1 is a diagram for explaining a pilot type solenoid valve 100 according to this embodiment. Fig. 1 illustrates a state in which a spool 230 of a main valve 200 and a spool 330 of a pilot valve 300 are disposed in a neutral position. As shown in Fig. 1, the pilot type solenoid valve 100 of this embodiment includes a main valve 200 that controls the direction in which hydraulic oil flows, a pilot valve 300 that operates the main valve 200, and an abnormality determination unit 110 that determines an operational abnormality of the main valve 200. Note that a first abnormality determination unit 110a or a second abnormality determination unit 110b described later is used as the abnormality determination unit 110.

[0012] (Pilot valve 300) The pilot valve 300 includes a spool 330, solenoids 340a and 340b that operate the spool 330 of the pilot valve 300, and a pilot valve side switch 380 that detects the neutral position and the switching position of the spool 330 of the pilot valve 300.

[0013] The pilot valve 300 has a cylindrical sleeve 310 in which multiple discharge ports 312a, 312b are formed, and a pair of casings 320a, 320b are arranged on both sides of the sleeve 310. A spool 330 is arranged inside the sleeve 310, and the multiple discharge ports 312a, 312b are switched by the spool 330 reciprocating in the axial direction of the sleeve 310. The hydraulic oil from the discharge ports 312a, 312b is sent to the main valve 200.

[0014] The casings 320a, 320b accommodate solenoids 340a, 340b, plungers 350a, 350b, a fixed core 360, and a rod 370. When a current is supplied to the solenoids 340a, 340b, they are energized and excited.

[0015] 1, when solenoid 340a on the right side is excited, plunger 350a is attracted to the fixed core housed in casing 320a, and plunger 350a presses rod 370 leftward in the figure against spool 330. As a result, spool 330 moves leftward inside sleeve 310, opening discharge port 312b and closing discharge port 312a.

[0016] 1, when solenoid 340b on the left side is excited, plunger 350a is attracted to fixed core 360 ​​housed in casing 320b, and plunger 350b presses rod 370 to the right in the figure against spool 330. As a result, spool 330 moves to the right inside sleeve 310, discharge port 312a opens, and discharge port 312b closes.

[0017] The pilot valve side switch 380 is composed of a first switch 380a and a second switch 380b attached to the sleeve 310. The first switch 380a and the second switch 380b each have a detection sensor 382 arranged in the casings 320a and 320b. The detection sensor 382 is arranged in the sleeve 310 so as to protrude into the path along which the spool 330 reciprocates.

[0018] The diameter of the spool 330 is larger than the diameter of the rod 370, and the tip of the detection sensor 382 is disposed at a position where it contacts the outer circumferential surface of the spool 330. As illustrated in the pilot valve 300 of Fig. 1, when the spool 330 is not moving in either the left or right direction in the drawing, that is, in the neutral state, both the first switch 380a and the second switch 380b are ON.

[0019] When the first switch 380a on the right side is turned OFF, it is detected that the spool 330 has moved leftward in the figure and is in the switching position (the second switch 380b remains ON). Conversely, when the second switch 380b on the left side is turned OFF, it is detected that the spool 330 has moved rightward in the figure and is in the switching position (the first switch 380a remains ON).

[0020] Therefore, when the first switch 380a and the second switch 380b are both ON, the first monitoring unit 112 (see FIG. 2) determines that the spool 330 is in the neutral position and outputs an "ON" signal. When the first switch 380a and the second switch 380b are a combination of ON / OFF, the first monitoring unit 112 determines that the spool 330 is in the switching position and outputs an "OFF" signal.

[0021] (Main valve 200) The main valve 200 includes a spool 230 that operates with the pressure of the pilot valve 300, a solenoid 240a and a solenoid 240b that forcibly operate the spool 230 of the main valve 200, and a main valve side switch 280 that detects the neutral position and the switched position of the spool 230 of the main valve 200.

[0022] The main valve 200 has a cylindrical sleeve 210 in which multiple discharge ports 212a, 212b are formed, and a pair of casings 220a, 220b are arranged on both sides of the sleeve 210. A spool 230 is arranged inside the sleeve 210, and the multiple discharge ports 212a, 212b are switched by the spool 230 reciprocating in the axial direction of the sleeve 210. The hydraulic oil from the discharge ports 212a, 212b is sent to industrial equipment (not shown).

[0023] Spool 230 of main valve 200 is operated by the pressure of hydraulic oil (pressurized oil) supplied from discharge ports 312a, 312b of pilot valve 300. Oil passages 214a, 214b and oil chambers 216a, 216b are formed in sleeve 210. Oil passage 214a communicates between discharge port 312a and oil chamber 216a, and oil passage 214b communicates between discharge port 312b and oil chamber 216b.

[0024] 1, when the discharge port 312a on the right side is opened (discharge port 312b is closed), the pressure of the hydraulic oil supplied to the oil chamber 216a through the oil passage 214a moves the spool 230 leftward inside the sleeve 210. As a result, the discharge port 212b is opened and the discharge port 212a is closed.

[0025] 1, when discharge port 312b on the left side of the figure is opened (discharge port 312a is closed), the pressure of the hydraulic oil supplied to oil chamber 216b through oil passage 214b causes spool 230 to move rightward inside sleeve 210. As a result, discharge port 212a is opened and discharge port 212b is closed.

[0026] The main valve side switch 280 is composed of a first switch 280a and a second switch 280b attached to the sleeve 210. The first switch 280a and the second switch 280b each have a detection sensor 282 arranged in the casings 220a and 220b. The detection sensor 282 is arranged in the sleeve 210 so as to protrude into the path along which the spool 230 reciprocates.

[0027] The diameter of the spool 230 is larger than the diameter of the rod 270, and the tip of the detection sensor 282 is disposed at a position where it contacts the outer circumferential surface of the spool 230. As illustrated in the main valve 200 of FIG. 1, when the spool 230 is not moving in either the left or right direction in the drawing, that is, in the neutral state, both the first switch 280a and the second switch 280b are ON.

[0028] When the first switch 280a on the right side is turned OFF, it is detected that the spool 230 has moved leftward in the figure and is in the switching position (the second switch 280b remains ON). Conversely, when the second switch 280b on the left side is turned OFF, it is detected that the spool 230 has moved rightward in the figure and is in the switching position (the first switch 280a remains ON).

[0029] Therefore, when the first switch 280a and the second switch 280b are both ON, the second monitoring unit 118 (see FIG. 2) determines that the spool 230 is in the neutral position and outputs an "ON" signal. When the first switch 280a and the second switch 280b are in a combination of ON / OFF, the second monitoring unit 118 determines that the spool 330 is in the switching position and outputs an "OFF" signal.

[0030] Furthermore, the main valve 200 of this embodiment is capable of forcibly operating the spool 230 by the solenoids 240a, 240b. In detail, the solenoids 240a, 240b, the plungers 250a, 250b, the fixed core 260, and the rod 270 are housed inside the casings 220a, 220b.

[0031] When current is supplied to the solenoids 240a and 240b, they are energized and excited. When the solenoid 240a on the right side in the state shown in Fig. 1 is excited, the plunger 250a is attracted to the fixed core 260 housed in the casing 220a, and the plunger 250a presses the rod 270 against the spool 230 in the leftward direction in the figure. As a result, the spool 230 moves leftward inside the sleeve 210, the discharge port 212b opens, and the discharge port 212a closes.

[0032] 1, when solenoid 240b on the left side is excited, plunger 250b is attracted to fixed core 260 housed in casing 220b, and plunger 250b presses rod 270 to the right in the figure against spool 230. As a result, spool 230 moves to the right inside sleeve 210, discharge port 212a opens, and discharge port 212b closes.

[0033] Even when the spool 230 is forcibly moved by the solenoids 240a, 240b, the detection sensor 282 of the main valve side switch 280 is turned ON / OFF by the moved spool 230. Therefore, it is possible to determine whether the spool 230 is in the switched position or the neutral position depending on whether or not there is contact with the detection sensor 282 of the main valve side switch 280.

[0034] (First abnormality determination unit 110a) 2 is a schematic diagram illustrating the configuration of the first abnormality determination unit 110a. The first abnormality determination unit 110a includes a first monitoring unit 112, a NOT circuit 114, a delay circuit 116, a second monitoring unit 118, and an AND circuit 120.

[0035] The first monitoring unit 112 monitors a signal from the pilot valve side switch 380. When the spool 330 is in the neutral position, the first monitoring unit 112 outputs an ON signal. When the spool 330 is in the switching position, the first monitoring unit 112 outputs an OFF signal.

[0036] The NOT circuit 114 inverts the signal input from the first monitoring unit 112 and outputs the inverted signal to the delay circuit 116. That is, by passing through the NOT circuit 114, when the spool 330 is in the switching position, the signal output to the delay circuit 116 is ON, and when the spool 330 is in the neutral position, the signal output to the delay circuit 116 is OFF.

[0037] The delay circuit 116 is an on-delay timer type, and when the signal input from the NOT circuit 114 turns ON, it outputs an ON signal to the AND circuit 120 after a predetermined settling time has elapsed. When the input signal turns OFF, it outputs an OFF signal as is. There is a time lag between the operation of the pilot valve 300 and the operation of the main valve 200. When the pilot valve 300 operates, the output of the NOT circuit 114 turns ON, and while the main valve 200 is not yet moving, the output of the second monitoring unit 118 also turns ON, so that both outputs turn ON instantaneously. Therefore, the delay circuit 116 is provided so that the ON signal of the NOT circuit 114 is not input to the AND circuit 120 before the main valve operates.

[0038] The second monitoring unit 118 monitors a signal from the main valve side switch 280. When the spool 230 is in the neutral position, the second monitoring unit 118 outputs an ON signal. When the spool 230 is in the switching position, the second monitoring unit 118 outputs an OFF signal.

[0039] The AND circuit 120 receives the "signal from the first monitoring unit 112 via the NOT circuit 114 and the delay circuit 116" and the "signal from the second monitoring unit 118." When both the "signal from 112 via the NOT circuit 114 and the delay circuit 116" and the "signal from the second monitoring unit 118" are ON, the AND circuit 120 determines that there is an abnormality in the main valve 200 because the spool 230 of the main valve 200 is in the neutral position even though the spool 330 of the pilot valve 300 is in the switching position. Therefore, the AND circuit 120 outputs an abnormality detection signal to the outside.

[0040] As described above, according to the pilot type solenoid valve 100 of this embodiment, the first abnormality judgment unit 110a can detect, from the outputs of the pilot valve side switch 380 and the main valve side switch 280, that the spool 330 of the pilot valve 300 is in the switching position and the spool 230 of the main valve 200 is in the neutral position.

[0041] This makes it possible to determine that the cause of the malfunction (abnormality) in which the pilot valve 300 cannot operate the spool 230 of the main valve 200 is not a switching failure of the spool 330 of the pilot valve 300, but a lack of pilot pressure or an operational malfunction of the spool 230 of the main valve 200. This makes it possible to quickly respond to the work to restore the abnormality.

[0042] (Second abnormality determination unit 110b) 3 is a schematic diagram for explaining the configuration of the second abnormality judgment unit 110b. The second abnormality judgment unit 110b includes a first monitoring unit 112, a NOT circuit 114, a delay circuit 116, a second monitoring unit 118, an AND circuit 120, a second delay circuit 130, a current application execution unit 132, and a second AND circuit 134. In the second abnormality judgment unit 110b, components common to the first abnormality judgment unit 110a are denoted by the same reference numerals and will not be described.

[0043] In the second abnormality judgment unit 110b shown in FIG. 3, when the AND circuit 120 detects that "the spool 330 of the pilot valve 300 is operating but the spool 230 of the main valve 200 is not operating (the spool 330 of the pilot valve 300 is in the switching position and the spool 230 of the main valve 200 is in the neutral position)", it outputs an abnormality detection signal to the current supply execution unit 132.

[0044] When the abnormality detection signal is input from the AND circuit 120, the energization execution unit 132 energizes the solenoids 240a, 240b of the main valve 200 and outputs an energization ON signal to the second AND circuit 134. As described above, when the solenoids 240a, 240b of the main valve 200 are energized, the switching operation of the spool 230 of the main valve 200 is performed by the solenoids 240a, 240b.

[0045] The second delay circuit 130 is of an on-delay timer type, and outputs the signal input from the second monitoring unit 118 to the second AND circuit 134 after a predetermined settling time has elapsed. This makes it possible to align the timing at which the energization ON signal output from the energization execution unit 132 is input to the second AND circuit 134 and the timing at which the signal output from the second monitoring unit 118 is input to the second AND circuit 134, thereby making it possible to prevent the occurrence of a time lag.

[0046] The second AND circuit 134 receives the power ON signal output by the power supply execution unit 132 and the signal output by the second monitoring unit 118. When both of these signals are ON, the second AND circuit 134 determines that there is an abnormality in the main valve 200 because the spool 230 of the main valve 200 is in the neutral position even though the solenoids 240a, 240b of the main valve 200 are performing the switching operation of the spool 230. Therefore, the second AND circuit 134 outputs an abnormality detection signal to the outside.

[0047] As described above, according to the pilot type solenoid valve 100 of this embodiment, the second abnormality determination unit 110b can "detect that the solenoids 240a, 240b of the main valve 200 are energized and that the spool 230 of the main valve 200 is in the neutral position." This makes it possible to determine that the cause of the malfunction (abnormality) in which the spool 230 of the main valve 200 cannot be operated is not insufficient pilot pressure, but that the spool 230 of the main valve 200 cannot move (due to distortion, contamination, etc.), thereby enhancing the above-mentioned effect.

[0048] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an example. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that such examples also naturally belong to the technical scope of the present invention. [Industrial Applicability]

[0049] INDUSTRIAL APPLICABILITY The present invention can be used as a pilot type solenoid valve that includes a main valve that controls the direction in which hydraulic oil flows, and a pilot valve that operates the main valve. [Explanation of symbols]

[0050] 100...pilot type solenoid valve, 110...abnormality determination unit, 110a...first abnormality determination unit, 110b...second abnormality determination unit, 112...first monitoring unit, 114...NOT circuit, 116...delay circuit, 118...second monitoring unit, 120...AND circuit, 130...second delay circuit, 132...energization execution unit, 134...second AND circuit, 200...main valve, 210...sleeve, 212a...discharge port, 212b...discharge port, 214a...oil passage, 214b...oil passage, 216a...oil chamber, 216b...oil chamber, 220a...casing, 220b...casing, 230...spool, 240a...solenoid, 240b...solenoid, 25 0a...plunger, 250b...plunger, 260...fixed core, 270...rod, 280...main valve side switch, 280a...first switch, 280b...second switch, 282...detection sensor, 300...pilot valve, 310...sleeve, 312a...discharge port, 312b...discharge port, 320a...casing, 320b...casing, 330...spool, 340a...solenoid, 340b...solenoid, 350a...plunger, 350b...plunger, 360...fixed core, 370...rod, 380...pilot valve side switch, 380a...first switch, 380b...second switch, 382...detection sensor

Claims

1. A main valve that controls the direction of hydraulic oil flow; a pilot valve for operating the main valve; an abnormality determination unit that determines an operational abnormality of the main valve; Including, The pilot valve is A spool and a solenoid for operating a spool of the pilot valve; a pilot valve side switch for detecting a neutral position and a switching position of a spool of the pilot valve; having The main valve is a spool operated by the pressure of the pilot valve; A solenoid for forcibly operating a spool of the main valve; a main valve side switch for detecting a neutral position and a switching position of a spool of the main valve; having a first switch for switching the pilot valve side switch to a first position and a second switch for switching the main valve side switch to a second position;

2. The abnormality determination unit is When it is detected that the spool of the main valve is not moving while the spool of the pilot valve is moving, the solenoid of the main valve is energized; 2. The pilot type solenoid valve according to claim 1, wherein when it is detected that the solenoid of the main valve is energized and the spool of the main valve is in a neutral position, it is determined that there is an abnormality in the main valve.

Images