Two-stage pressure control valve

Abstract

To provide a two-stage pressure control valve which can output fluids with different pressures in one valve body without needing an additional device, in particular, can set a high pressure and a low pressure separately to enable an arbitrary setting of a pressure adjustment range.SOLUTION: A two-stage pressure control valve 100 includes: a valve element 110 which allows communication or interrupts communication between an input port 106 and an output port 108 of a valve body 102; a solenoid 112 housed in a retainer body 104 located adjacent to the valve body; a movable iron core 114 which moves so as to come close to the valve element when the solenoid is energized; a sleeve 126 which is screwed into the retainer body to move forward to and rearward from the valve element; a high pressure side stopper 124 which is attached the sleeve to limit a movable range of the movable iron core to the valve element side; a low pressure adjustment screw 132 which is inserted into the movable iron core to be coaxially screwed into the sleeve and moves forward to and rearward from the valve element; a lower pressure spring 134 disposed between the valve element and the low pressure adjustment screw; and a high pressure spring 118 disposed between the valve element and the movable iron core.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a two-stage pressure control valve that outputs fluids at different pressures. [Background technology]

[0002] In hydraulic circuits that supply hydraulic pressure to hydraulic drive units, two-stage pressure control valves that output fluids at different pressures (two pressures) are sometimes used. Examples of two-stage pressure control valves include two-pressure reducing valves, two-stage relief valves, and two-pressure pressure control valves.

[0003] For example, Patent Document 1 discloses a two-stage proportional pressure reducing valve. This two-stage proportional pressure reducing valve comprises "a solenoid valve, a valve body oriented in the axial direction of the solenoid valve and integrally attached to the solenoid valve, a sleeve slidably inserted into the valve body and having a drain port, first and second discharge ports, and an input port formed in the axial direction and perpendicular to the axial direction at intervals, a proportional pressure reducing valve section attached to the valve body and adjusting the set pressure, and a pressure reducing valve section attached to the valve body and reducing the pressure to below the maximum operating pressure." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-142696 Summary of the Invention [Problem to be solved by the invention]

[0005] The two-stage proportional pressure reducing valve of Patent Document 1 claims that two-stage pressure reduction from high pressure to low pressure, which was previously achieved using two pressure reducing valves, can now be achieved with a single pressure reducing valve. However, this two-stage proportional pressure reducing valve configuration requires the addition of a new proportional pressure reducing valve unit (electromagnetic proportional valve), and also requires a drive amplifier to control the current in the proportional pressure reducing valve unit. This leads to increased equipment costs and an increase in the size of the equipment, leaving room for further improvement in the technology of Patent Document 1.

[0006] In view of these problems, the present invention aims to provide a two-stage pressure control valve that can output fluids of different pressures from a single valve body without requiring additional equipment, and in particular, that can set low and high pressures separately to arbitrarily set the pressure adjustment range. [Means for solving the problem]

[0007] In order to solve the above problems, a representative configuration of a two-stage pressure control valve according to the present invention is characterized by comprising: a valve body provided with an input port and an output port; a valve element housed in the valve body and establishing or blocking communication between the input port and the output port; a retainer body adjacent to the valve body; a solenoid housed in the retainer body; a movable iron core that moves toward the valve element when the solenoid is energized; a sleeve that is threaded into the retainer body and moves back and forth toward the valve element; a high-pressure side stopper that is attached to the sleeve and limits the range of movement of the movable iron core toward the valve element; a low-pressure adjustment screw that is inserted into the movable iron core and threaded coaxially into the sleeve and moves back and forth toward the valve element; a low-pressure spring arranged between the valve element and the low-pressure adjustment screw; and a high-pressure spring arranged coaxially with the low-pressure spring between the valve element and the movable iron core.

[0008] When the solenoid is not energized and the movable iron core is located at a position away from the valve body, the distance between the valve body and the movable iron core is preferably longer than the free length of the high-pressure spring. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a two-stage pressure control valve that can output fluids of different pressures using a single valve body without requiring additional equipment, and in particular, that can set the low pressure and high pressure separately to freely set the pressure adjustment range. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a two-stage pressure control valve according to an embodiment of the present invention. FIG. [Figure 2] 2 is a diagram showing a state when the two-stage pressure control valve of FIG. 1 is energized. FIG. [Figure 3] 2 is a diagram illustrating the low-pressure side adjustment of the two-stage pressure control valve of FIG. 1. FIG. [Figure 4] 10A and 10B are diagrams illustrating changes in various parts that occur as the high-voltage side stopper moves when the solenoid is energized. 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] 1 is a diagram illustrating a two-stage pressure control valve 100 according to an embodiment of the present invention. In this embodiment, a two-pressure reducing valve is exemplified as the two-stage pressure control valve 100, but the present invention is not limited to this and can also be applied to a two-stage relief valve.

[0013] The two-stage pressure control valve 100 includes a valve body 102 and a retainer body 104 disposed adjacent to the valve body 102. The valve body 102 is formed with an input port 106 and an output port 108. The valve body 102 also houses a valve element 110 (poppet valve).

[0014] The valve element 110 is provided between the input port 106 and the output port 108. As will be described in detail later, the valve element 110 switches from a closed state to an open state when subjected to a predetermined pressure of a fluid such as hydraulic oil. In the open state, the valve element 110 connects the input port 106 to the output port 108, and in the closed state, it blocks communication. A fluid such as hydraulic oil is supplied to the valve body 102 through the input port 106 and is reduced in pressure in the two-stage pressure control valve 100. The fluid is then sent to a hydraulic circuit (not shown) through the output port 108 via the valve element 110 in the open state. Note that although the input port 106 and the output port 108 are illustrated as part of the two-stage pressure control valve 100, they may also be considered part of the hydraulic circuit because they are connected to a hydraulic circuit located outside the two-stage pressure control valve 100.

[0015] A solenoid 112 is housed in the retainer body 104. A movable iron core 114 (also referred to as a plunger) is housed inside the solenoid 112. The movable iron core 114 is made of a magnetic material or contains a magnetic material. The movable iron core 114 moves toward the valve element 110 when the solenoid 112 is energized. FIG. 1 shows an example of a state when the solenoid 112 is not energized. That is, FIG. 1 shows a state when the solenoid 112 is not energized and a high-pressure side stopper 124 (described below) is separated from the valve element 110. Other states will be described later with reference to other figures.

[0016] Furthermore, a high-pressure spring 118 is disposed between the valve body 110 and an end face 116 of the movable iron core 114 facing the valve body 110. The high-pressure spring 118 biases the movable iron core 114 and the valve body 110 in a direction separating them. Therefore, the high-pressure spring 118 serves to bias the valve body 110 and the movable iron core 114, and also serves as a return spring that returns the movable iron core 114 to its initial position (the position before it was attracted by the solenoid 112).

[0017] However, as shown in Figure 1, when the high-pressure side stopper 124 is not energized and is separated from the valve disc 110, the high-pressure spring 118 does not bias the valve disc 110 and the movable iron core 114 in a direction separating the valve disc 110 and the movable iron core 114. This is because the distance between the valve disc 110 and the end face 116 of the movable iron core 114 facing the valve disc 110 is longer than the free length of the high-pressure spring 118. In other words, the high-pressure spring 118 is not compressed, for example, because one end of the high-pressure spring 118 is separated from the end face 116 of the movable iron core 114 facing the valve disc 110. However, if the sleeve 126 that positions the high-pressure side stopper 124 is rotated with a tool (described later) to move the high-pressure side stopper 124 extremely toward the valve disc 110, the high-pressure spring 118 may no longer have its free length. The end of the valve body 110 side in the "distance between the end face 116 of the movable iron core 114 and the valve body 110" is a surface 117 of the flange portion 111 of the valve body 110 on the movable iron core 114 side. This surface 117 of the valve body 110 is at the same position in the axial direction of the high-pressure spring 118 as the base end of the other-end-side accommodation chamber 110a, which will be described later.

[0018] The two-stage pressure control valve 100 further has a high-pressure side block 120. The high-pressure side block 120 is configured to include a high-pressure side stopper 124 and a sleeve 126 joined to the high-pressure side stopper 124. The sleeve 126 is made of or includes a non-magnetic material. The sleeve 126 also has the movable iron core 114 inserted therein to position the high-pressure side stopper 124. The high-pressure side stopper 124 is made of or includes a magnetic material. The high-pressure side stopper 124 is disposed on the valve disc 110 side of the movable iron core 114 and functions as a fixed iron core. The high-pressure side stopper 124 limits the range of movement of the movable iron core 114 toward the valve disc 110 side.

[0019] A sleeve 126 included in the high-pressure side block 120 is disposed between the solenoid 112 and the movable iron core 114 in the retainer body 104. Hereinafter, the space inside the retainer body 104 in which the high-pressure side block 120 can move is referred to as a piston chamber 122.

[0020] The sleeve 126 has a thread groove 126a formed on its outer circumferential surface, is threaded into the cap 130 of the retainer body 104, and moves toward and away from the valve disc 110. A nut 128, which is a double nut for fixing, is attached to the side of the sleeve 126 that is exposed from the retainer body 104. The end of the sleeve 126 that is exposed from the retainer body 104 has a two-sided cut 126b that can be clamped with a tool (not shown) such as a wrench. The valve disc 110 side of the sleeve 126 is cylindrical as shown in FIG. 1, and the movable iron core 114 is housed inside the cylinder so that it can move in the axial direction of the high-pressure spring 118.

[0021] The two-stage pressure control valve 100 further includes a low-pressure adjusting screw 132 and a low-pressure spring 134. The low-pressure adjusting screw 132 is inserted through the movable iron core 114 and is coaxially threadedly engaged with the sleeve 126. The low-pressure adjusting screw 132 advances and retreats toward the valve element 110.

[0022] A double fixing nut 136 is attached to the side of low-pressure adjusting screw 132 that is exposed from sleeve 126. A hexagonal hole 132a is formed in the end of low-pressure adjusting screw 132 that is exposed from sleeve 126, into which a tool (not shown) such as a hexagonal wrench can be inserted.

[0023] Furthermore, a one-end housing chamber 132b that houses one end 134a of a low-pressure spring 134 is formed at the end of the low-pressure adjustment screw 132 on the valve body 110 side. Also, an other-end housing chamber 110a that houses the other end of the low-pressure spring 134 is attached to the surface 117 of the flange portion 111 of the valve body 110. As a result, the low-pressure spring 134 is disposed between the valve body 110 and the low-pressure adjustment screw 132 as shown. Also, the low-pressure spring 134 and the high-pressure spring 118 are disposed coaxially.

[0024] In this way, in the two-stage pressure control valve 100, the low-pressure spring 134 is disposed between the valve element 110 and the low-pressure adjusting screw 132, and the low-pressure adjusting screw 132 is inserted into the movable iron core 114. Therefore, the low-pressure spring 134 can press the valve element 110 to close it without being affected by the position of the movable iron core 114.

[0025] As described above, when the solenoid 112 is not energized, the high-pressure spring 118 is at its free length and is not compressed. On the other hand, the low-pressure spring 134 is slightly compressed between the valve element 110 and the low-pressure adjusting screw 132. For this reason, in the two-stage pressure control valve 100, when the solenoid 112 is not energized, the valve element 110 can be pressed to close only by the biasing force of the low-pressure spring 134.

[0026] As a result, when the pressure of the fluid supplied from the input port 106 is greater than the biasing force of the low-pressure spring 134 pressing the valve element 110, the valve element 110 essentially moves toward the movable iron core 114, the valve opens, and the fluid is sent to the hydraulic circuit from the output port 108. In other words, in the two-stage pressure control valve 100, when the solenoid 112 is not energized, the biasing force of the low-pressure spring 134 becomes the relief pressure during low pressure conditions.

[0027] Figure 2 is a diagram showing the state when current is applied to the two-stage pressure control valve 100 in Figure 1. A high-pressure-side stopper 124 attached to a sleeve 126 of the high-pressure-side block 120 regulates the position of the movable iron core 114 on the valve element 110 side and functions as a fixed iron core. Therefore, when the solenoid 112 is energized, the movable iron core 114 moves closer to the valve element 110 as shown in the figure, and is then attracted to the high-pressure-side stopper 124.

[0028] Furthermore, a high-pressure spring 118 is disposed coaxially with the low-pressure spring 134 between the valve element 110 and the movable iron core 114. For this reason, when the movable iron core 114 approaches the valve element 110 while the solenoid 112 is energized, the high-pressure spring 118, which has a free length when not energized, is compressed, and the spring exerts a biasing force greater than that of the low-pressure spring 134, pressing the valve element 110 substantially in the opposite direction to the movable iron core 114. In other words, when the solenoid 112 is energized, the high-pressure spring 118 and the low-pressure spring 134 bias the valve element 110 to close the valve.

[0029] That is, in the two-stage pressure control valve 100, the amount of compression of the high-pressure spring 118 can be changed by moving the movable iron core 114. Then, by adjusting the position of the high-pressure side block 120 to change the amount of compression of the high-pressure spring 118, the biasing force of the high-pressure spring 118 pressing the valve element 110 can be adjusted.

[0030] On the other hand, the low-pressure spring 134 presses the valve element 110 to close it without being affected by the position of the movable iron core 114, and therefore urges the valve element 110 with the same force even when the solenoid 112 is energized as when it is not energized.

[0031] Therefore, in the two-stage pressure control valve 100, when the solenoid 112 is energized, the valve element 110 can be pressed by the biasing force of the high-pressure spring 118 in addition to the biasing force of the low-pressure spring .

[0032] As a result, when the pressure of the fluid supplied from the input port 106 is greater than the force pressing the valve body 110 (i.e., the force obtained by adding the force of the low-pressure spring 134 to the force of the high-pressure spring 118), the valve body 110 moves toward the movable iron core 114, opening the valve, and the fluid is sent from the output port 108 to the hydraulic circuit.

[0033] That is, in the two-stage pressure control valve 100, when the solenoid 112 is energized, the biasing force of the low-pressure spring 134 plus the biasing force of the high-pressure spring 118 becomes the relief pressure at high pressure. Therefore, with the two-stage pressure control valve 100, the difference between the biasing force at low pressure and the biasing force at high pressure acting on the valve element 110 (difference in relief pressure) can be freely set.

[0034] Figure 3 is a diagram illustrating the low-pressure side adjustment of the two-stage pressure control valve 100 of Figure 1. The figure shows a state when the solenoid 112 is not energized, exemplifying a state in which the high-pressure spring 118 is at its free length and the low-pressure spring 134 is compressed between the valve body 110 and the low-pressure adjustment screw 132.

[0035] As described above, the low-pressure adjustment screw 132 is threadedly engaged with the sleeve 126, and moves toward and away from the valve element 110. Therefore, by using a tool to rotate the low-pressure adjustment screw 132 relative to the sleeve 126, the low-pressure adjustment screw 132 can be moved closer to or farther away from the valve element 110. This makes it possible to adjust the biasing force of the low-pressure spring 134, which is arranged between the valve element 110 and the low-pressure adjustment screw 132.

[0036] Specifically, when a tool is inserted into the hexagonal hole 132a of the low-pressure adjusting screw 132 and the low-pressure adjusting screw 132 is rotated in the direction A shown in Figure 3(a) (twisted to the right), the low-pressure adjusting screw 132 moves in the direction D1 toward the valve body 110. When the low-pressure adjusting screw 132 has fully moved in the direction D1 as shown in Figure 3(a), one end 134a of the low-pressure spring 134 housed in the one-end housing chamber 132b of the low-pressure adjusting screw 132 is positioned at P1.

[0037] Furthermore, when a tool is inserted into the hexagonal hole 132a of the low-pressure adjustment screw 132 and the low-pressure adjustment screw 132 is rotated in the direction B shown in Figure 3(b) (twisted to the left), the low-pressure adjustment screw 132 moves in the direction D2 so as to move away from the valve body 110. When the low-pressure adjustment screw 132 has fully moved in the direction D2 as shown in Figure 3(b), one end 134a of the low-pressure spring 134 is positioned at P2.

[0038] Therefore, the movable range of the low-pressure spring 134 is from P1 to P2, and by moving the low-pressure adjustment screw 132 within this range, the spring force of the low-pressure spring 134 can be adjusted to adjust the pressure on the low-pressure side, i.e., the pressure during low-pressure output.

[0039] 4 shows the changes in each part that occur as the high-pressure side stopper 124 moves when current is applied to the solenoid 112. When current is applied to the solenoid 112, the movable iron core 114 is attracted to the high-pressure side stopper 124 attached to the sleeve 126, and the high-pressure spring 118 is compressed between the valve body 110 and the movable iron core 114.

[0040] As described above, the sleeve 126 is threadedly engaged with the retainer body 104 and moves toward and away from the valve disc 110. For example, the sleeve 126 is rotated relative to the retainer body 104 by a tool. Depending on the direction of rotation of the sleeve 126, the high-pressure side stopper 124 attached to the sleeve 126 can be moved toward or away from the valve disc 110. The high-pressure spring 118 is disposed between the valve disc 110 and the movable iron core 114 attracted to the high-pressure side stopper 124 when the solenoid 112 is energized. Therefore, the biasing force of the high-pressure spring 118 can be adjusted by using the high-pressure side stopper 124 to restrict the position of the movable iron core 114 on the valve disc 110 side.

[0041] Specifically, when the two-sided cut 126b of the sleeve 126 is clamped with a tool and the sleeve 126 is rotated in the direction C shown in Figure 4(a) (twisted to the left), the high-pressure-side stopper 124 of the high-pressure-side block 120 moves in the direction D3 so as to move away from the valve body 110. When the high-pressure-side stopper 124 has completely moved the piston chamber 122 in the direction D3 as shown in Figure 4(a), the end face 116 of the movable iron core 114 on the valve body 110 side is positioned at P3.

[0042] Furthermore, when the two-sided cut 126b of the sleeve 126 is clamped with a tool and the sleeve 126 is rotated in the direction D shown in Figure 4(b) (twisted to the right), the high-pressure side stopper 124 moves in the direction D4 toward the valve body 110. When the high-pressure side stopper 124 has completely moved the piston chamber 122 in the direction D4 as shown in Figure 4(b), the end face 116 of the movable iron core 114 on the valve body 110 side is positioned at P4.

[0043] Therefore, the movable range of the high-pressure spring 118 is from P3 to P4, and by moving the high-pressure side stopper 124 within this range, the spring force of the high-pressure spring 118 can be adjusted to adjust the pressure on the high-pressure side, i.e., the pressure during high-pressure output.

[0044] As described above, in the two-stage pressure control valve 100 of this embodiment, when the solenoid 112 is not energized, the high-pressure spring 118 is at its free length, and the low-pressure spring 134 biases the valve element 110, thereby supplying a fluid that has been adjusted to a low pressure. Furthermore, when the solenoid 112 is energized, the movable iron core 114 is attracted to the high-pressure-side stopper 124, and the high-pressure spring 118 is compressed. Therefore, in the two-stage pressure control valve 100, when the solenoid 112 is energized, the low-pressure spring 134 biases the valve element 110, and the high-pressure spring 118 biases the valve element 110, thereby supplying a fluid that has been adjusted to a high pressure.

[0045] Therefore, with the two-stage pressure control valve 100, it is possible to output fluids of different pressures from one valve element 110. In particular, the biasing force of the high-pressure spring 118 can be adjusted by moving the sleeve 136 toward or away from the valve element 110 to position the high-pressure side stopper 124, and the biasing force of the low-pressure spring 118 can be adjusted by moving the low-pressure adjustment screw 132 toward or away from the valve element 110. Therefore, with the two-stage pressure control valve 100, the low pressure and high pressure can be set separately, allowing the pressure adjustment range to be set as desired (wide).

[0046] Furthermore, while the high-pressure spring 118 has a free length when the solenoid 112 is not energized, this is not limiting. As an example, the high-pressure spring 118 may be slightly compressed even when the solenoid 112 is not energized by adjusting the distance between the valve element 110 and the end face 116 of the movable iron core 114 on the valve element 110 side, or the free length of the high-pressure spring 118, thereby increasing the pressure during low-pressure adjustment.

[0047] In the above configuration, the only additional parts are the high-pressure side block 120, the low-pressure adjustment screw 132, and the low-pressure spring 134, which are housed in the retainer body 104. Therefore, there is no need to add a new device such as an amplifier for the solenoid proportional valve, and the above-mentioned effects can be obtained without increasing the cost or size of the device.

[0048] 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. [Explanation of symbols]

[0049] 100... Two-stage pressure control valve, 102... Valve body, 104... Retainer body, 106... Input port, 108... Output port, 110... Valve disc, 111... Flange portion of valve disc, 110a... Other end side accommodating chamber, 112... Solenoid, 114... Moving iron core, 116... End face of moving iron core on the valve disc side, 117... Face of valve disc, 118... High pressure spring, 120... High pressure side block, 122... Piston chamber, 124... High pressure side stopper, 126... Sleeve, 126a... Thread groove of sleeve, 126b... Two-sided cut of sleeve, 128, 136... Nut, 130... Cap, 132... Low pressure adjustment screw, 132a... Hexagonal hole of low pressure adjustment screw, 132b... One end side accommodating chamber of low pressure adjustment screw, 134... Low pressure spring, 134a... One end of low pressure spring

Claims

1. a valve body provided with an input port and an output port; a valve element housed in the valve body and configured to establish or block communication between the input port and the output port; a retainer body adjacent to the valve body; a solenoid housed in the retainer body; a movable core that moves toward the valve body when the solenoid is energized; a sleeve that is threadedly engaged with the retainer body and moves toward and away from the valve body; a high-pressure side stopper attached to the sleeve and limiting the range of movement of the movable iron core toward the valve body; a low-pressure adjusting screw that is inserted through the movable iron core, is coaxially threadedly engaged with the sleeve, and moves toward and away from the valve body; a low-pressure spring disposed between the valve body and the low-pressure adjusting screw; a high-pressure spring disposed coaxially with the low-pressure spring between the valve body and the movable iron core; A two-stage pressure control valve comprising:

2. 2. The two-stage pressure control valve according to claim 1, wherein when the solenoid is not energized and the movable core is located at a position away from the valve body, the distance between the valve body and the movable core is longer than the free length of the high-pressure spring.

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