Electromagnetic relief valve

Abstract

This electromagnetic relief valve (100) comprises: a pilot poppet (20) that connects or disconnects a high-pressure-side passage (HP) and a low-pressure-side passage (LP); a valve body chamber (VS) that accommodates the pilot poppet (20); and a solenoid part (S) that biases the pilot poppet (20) in a valve-closing direction. The solenoid unit (S) has a plunger (72), a rod (73), a spring (74) that biases the pilot poppet (20) in the valve closing direction, and a plunger chamber (76) in which the plunger (72) is accommodated. A partition member (90) that partitions the valve body chamber (VS) and the plunger chamber (76) and has a through-hole (60d) through which the rod (73) passes is provided between the valve body chamber (VS) and the plunger chamber (76). An annular throttle (C) is provided between the through-hole (60d) of the partition member (90) and the rod (73).

Description

Solenoid Relief Valve

[0001] The present invention relates to an electromagnetic relief valve.

[0002] JP2022-12406A discloses an electromagnetic relief valve that opens when the pressure of hydraulic oil in a high-pressure passage reaches a set pressure, and releases the hydraulic oil from the high-pressure passage to a low-pressure passage, thereby preventing the pressure of the hydraulic oil in the high-pressure passage from becoming abnormally high.

[0003] The electromagnetic relief valve described in JP2022-12406A is provided with a solenoid portion that allows the set pressure to be changed.

[0004] The electromagnetic relief valve described in JP2022-12406A is inspected before shipping, then transported, and then attached to hydraulic equipment such as a valve block. At this time, with the electromagnetic relief valve described in Patent Document 1, air may enter the valve due to the effects of vibrations during transportation, and air may become trapped in the spring chamber that houses the spring that biases the plunger of the solenoid.

[0005] In this state, if the pressure on the low-pressure side (relief side) fluctuates when the pilot poppet opens, the pressure fluctuation acts on the plunger, causing it to move. If air remains in the valve at this time, the air expands and contracts as the plunger moves, causing a mismatch between the pressure fluctuation and the movement of the plunger, which can lead to unstable operation of the electromagnetic relief valve.

[0006] An object of the present invention is to provide an electromagnetic relief valve that operates stably even if air gets inside the electromagnetic relief valve.

[0007] According to one aspect of the present invention, there is provided an inverse proportion type electromagnetic relief valve comprising: a valve element which connects or disconnects a high-pressure side passage and a low-pressure side passage; a valve element chamber which connects to the low-pressure side passage and houses the valve element; and a solenoid unit which urges the valve element in a valve closing direction. The solenoid unit comprises a plunger, a rod which is fixed to the plunger and has a tip which extends to the valve element chamber and abuts against the valve element, a biasing member which urges the valve element in the valve closing direction via the rod, a coil which generates a magnetic field when a current is applied and applies a reaction force to the plunger which opposes the biasing force of the biasing member, and a plunger chamber which is provided inside the coil and houses the plunger. Between the valve element chamber and the plunger chamber, there is provided a partition member which separates the valve element chamber and the plunger chamber and has a through hole through which the rod passes, and there is provided an annular throttle between the inner peripheral surface of the through hole of the partition member and the outer peripheral surface of the rod.

[0008] Fig. 1 is a cross-sectional view of an electromagnetic relief valve according to an embodiment of the present invention, and Fig. 2 is an enlarged cross-sectional view of the vicinity of an annular throttle C of the electromagnetic relief valve according to an embodiment of the present invention.

[0009] An electromagnetic relief valve 100 according to an embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view of the electromagnetic relief valve 100 according to this embodiment. Figure 2 is an enlarged cross-sectional view of the vicinity of an annular throttle C of the electromagnetic relief valve 100 according to this embodiment.

[0010] The electromagnetic relief valve 100 is an inverse proportional type electromagnetic relief valve, which is configured so that the relief pressure decreases as the value of current applied to a solenoid (described later) increases.

[0011] The electromagnetic relief valve 100 opens when the pressure of the hydraulic oil in the high-pressure passage H reaches a set pressure (relief pressure) and releases the hydraulic oil from the high-pressure passage H to the low-pressure passage L, thereby preventing the pressure of the hydraulic oil in the high-pressure passage H from becoming abnormally high. The electromagnetic relief valve 100 also has an anti-void function, and opens when the high-pressure passage H becomes negative pressure, supplying the hydraulic oil from the low-pressure passage L to the high-pressure passage H, thereby preventing the occurrence of cavitation.

[0012] As shown in Fig. 1, the electromagnetic relief valve 100 is attached to an equipment body 1 by screw fastening. The equipment body 1 is the main body of a hydraulic device such as a hydraulic cylinder, a hydraulic pump, a hydraulic motor, or a valve block having a plurality of valves. In this embodiment, an example will be described in which hydraulic oil is used as the working fluid for the equipment body 1, but the working fluid may be other liquids such as working water.

[0013] The device body 1 is provided with a high-pressure passage H and a low-pressure passage L, with the electromagnetic relief valve 100 as the boundary. The device body 1 is provided with a seat portion 1a serving as a first valve seat on which a suction poppet 3, which will be described later, sits, between the high-pressure passage H and the low-pressure passage L. The device body 1 is not limited to the main body of the hydraulic device, and may be a block body or the like installed between the hydraulic devices.

[0014] As shown in FIG. 1, the electromagnetic relief valve 100 includes a valve portion V for connecting or disconnecting a high-pressure passage H and a low-pressure passage L, and a solenoid portion S for adjusting a set pressure (relief pressure).

[0015] As shown in FIG. 1 , the valve section V includes a housing 2 attached to an equipment main body 1 in which a high-pressure passage H and a low-pressure passage L are provided, a suction poppet 3 as a first valve body provided in the housing 2 and which connects or disconnects the high-pressure passage H and the low-pressure passage L by lifting off or seating on a seat portion 1a, a main poppet 5 as a second valve body provided in the suction poppet 3 and which connects or disconnects the high-pressure passage H and the low-pressure passage L by lifting off or seating on a seat portion 3f as a second valve seat formed on the suction poppet 3, and a suction poppet 5 as a second valve body. Within the valve poppet 3, there is provided a back pressure chamber 8 into which hydraulic oil is introduced from the high pressure passage H to urge the main poppet 5 in the valve closing direction, a sleeve 7 which separates the back pressure chamber 8 from the main poppet 5, a pilot passage 10 which is provided in the main poppet 5 and which connects the high pressure passage H and the back pressure chamber 8, a drain chamber 12 which is provided in the sleeve 7 and from which the hydraulic oil in the back pressure chamber 8 is discharged, a first communication passage P1 which is provided in the sleeve 7 and which connects the drain chamber 12 and the back pressure chamber 8, and a pilot poppet 20 which is provided in the sleeve 7 and serves as a third valve body which opens and closes the first communication passage P1.

[0016] 1, the housing 2 is a cylindrical member having a first cylindrical portion 2a attached to the device body 1 and a second cylindrical portion 2b connected to a connecting member 90 on the opposite side of the first cylindrical portion 2a. The connecting member 90 connects the housing 2 to a solenoid housing 71 of the solenoid portion S. The housing 2 and the solenoid housing 71 in this embodiment correspond to the "valve housing" in the claims.

[0017] The suction poppet 3 is a cylindrical member having a cylindrical portion 3a and a bottom portion 3b. The suction poppet 3 is provided axially movable within the housing 2, with a portion of it protruding from the opening of the first cylindrical portion 2a of the housing 2. A high-pressure port 3H communicating with the high-pressure passage H is provided in the bottom portion 3b of the suction poppet 3, and a low-pressure port 3L communicating with the low-pressure passage L is provided near the bottom portion 3b of the cylindrical portion 3a.

[0018] A corner 3c between the cylindrical portion 3a and the bottom portion 3b of the suction poppet 3 is formed in a tapered shape, and when this corner 3c is seated on the seat portion 1a of the device body 1, communication between the high-pressure passage H and the low-pressure passage L through the device body 1 and the suction poppet 3 is blocked. A first accommodation hole 3d for accommodating the main poppet 5 is provided on the bottom portion 3b side of the suction poppet 3, and a second accommodation hole 3e, which has a larger diameter than the first accommodation hole 3d and for accommodating the sleeve 7, is provided at the end opposite the bottom portion 3b.

[0019] The main poppet 5 has a main body portion 50 that can slide within the first accommodating hole 3d, and a pilot piston 51 that can slide within a sliding hole 50a that is formed axially through the main body portion 50.

[0020] The main body 50 has a valve portion 50b that seats on a seat portion 3f formed inside a corner 3c of the suction poppet 3. When the valve portion 50b seats on the seat portion 3f, communication between the high-pressure passage H and the low-pressure passage L through the space between the suction poppet 3 and the main poppet 5 is blocked. A seal member (O-ring) is provided between the outer peripheral surface of the main body 50 and the inner peripheral surface of the suction poppet 3 to seal the gap between the main body 50 and the suction poppet 3.

[0021] The pilot piston 51 has a flange portion 51a provided facing the back pressure chamber 8, which is a space defined by the inner circumferential surface of the suction poppet 3, the main poppet 5, and the sleeve 7, and a cylindrical shaft portion 51b extending axially from the flange portion 51a and inserted into the slide hole 50a. The tip of the shaft portion 51b protrudes from the tip surface of the main body portion 50 facing the high-pressure passage H. The pilot piston 51 also has a pilot passage 10 that communicates between the high-pressure passage H and the back pressure chamber 8. The pilot passage 10 has a throttle that applies resistance to the hydraulic oil flowing through the pilot passage 10.

[0022] The sleeve 7 has a tip end 7a that is inserted into the suction poppet 3, a base end 7b that is connected to the connecting member 90, an accommodation hole 7c that opens to the axial end opposite the tip end 7a, and an intermediate portion 7d that is provided between the tip end 7a and the base end 7b and whose outer circumferential surface is exposed between the suction poppet 3 and the connecting member 90. The sleeve 7 slidably supports the suction poppet 3 at the tip end 7a. A seal member (O-ring) that seals the gap between the sleeve 7 and the suction poppet 3 is provided between the outer circumferential surface of the tip end 7a of the sleeve 7 and the inner circumferential surface of the suction poppet 3.

[0023] The sleeve 7 also has a first communication passage P1, one end of which opens into the back pressure chamber 8 and the other end of which opens into the bottom surface of the accommodating hole 7c, connecting the back pressure chamber 8 and the accommodating hole 7c, and a drain passage 13, one end of which opens into the inner surface of the accommodating hole 7c and the other end of which opens into the outer surface of the intermediate portion 7d.

[0024] A seat portion 11a on which the valve portion 22 of the pilot poppet 20 seats and disengages is provided at the open end of the first communication passage P1 that opens into the accommodation bore 7c. The seat portion 11a is formed coaxially with the accommodation bore 7c so that its central axis coincides with the central axis of the accommodation bore 7c. A throttle 11b that applies resistance to the flow of hydraulic oil through the first communication passage P1 is provided in the first communication passage P1 between the seat portion 11a and the back pressure chamber 8. In this embodiment, the first communication passage P1 corresponds to the "high-pressure side passage HP" in the claims.

[0025] The drain chamber 12 is a space defined by the receiving hole 7 c and the pilot poppet 20 .

[0026] The drain passage 13 is constantly in communication with the drain chamber 12 and the low-pressure passage L through a gap 14 between the outer peripheral surface of the suction poppet 3 and the inner peripheral surface of the housing 2. In this embodiment, the drain chamber 12 and the passage leading from the drain chamber 12 to the low-pressure passage L correspond to the "low-pressure side passage LP" in the claims.

[0027] 1, the pilot poppet 20 is a member formed in a substantially cylindrical shape and is accommodated in the accommodation hole 7c of the sleeve 7. The pilot poppet 20 has a main body portion 21 slidably supported in the accommodation hole 7c, and a conical valve portion 22 that protrudes axially from the main body portion 21.

[0028] The main body 21 of the pilot poppet 20 is provided with an annular groove 21a formed to be constantly in communication with the drain passage 13, a first notch 21b formed along the axial direction from the annular groove 21a toward the valve portion 22 side, and a second notch 21c formed along the axial direction from the annular groove 21a toward the solenoid portion S side.

[0029] The first cutout 21b is formed by cutting out a flat portion of the outer peripheral surface of the main body 21. The drain chamber 12 communicates with the low-pressure passage L through a passage defined by the inner peripheral surface of the accommodating hole 7c and the first cutout 21b, the annular groove 21a, the drain passage 13, and the gap 14. The passage defined by the inner peripheral surface of the accommodating hole 7c and the first cutout 21b also functions as a first throttle that applies resistance to the hydraulic oil discharged from the back pressure chamber 8 to the low-pressure passage L.

[0030] The second cutout 21c is formed by cutting out a flat portion of the outer peripheral surface of the main body 21 along the axial direction from the annular groove 21a toward the solenoid portion S so that the end on the solenoid portion S side is always exposed from the accommodating hole 7c. The space SP in the accommodating hole 90c of the connecting member 90, where the rear end side of the pilot poppet 20 is exposed, communicates with the low-pressure passage L through a passage defined by the inner peripheral surface of the accommodating hole 7c and the second cutout 21c, the annular groove 21a, the drain passage 13, and the gap 14. Hereinafter, the space formed by the accommodating hole 7c of the sleeve 7, the space SP, and the region of the communicating hole 90d on the space SP side relative to the reduced diameter portion 60e will be referred to as the valve element chamber VS that accommodates the pilot poppet 20.

[0031] The pilot poppet 20 thus formed is slidably supported by the accommodation hole 7c formed coaxially with the seat portion 11a. That is, the pilot poppet 20 is supported by the accommodation hole 7c so that its central axis is not tilted relative to the central axis of the seat portion 11a. In this way, the pilot poppet 20 is prevented from being tilted relative to the seat portion 11a, thereby preventing the valve portion 22 from making uneven contact with the seat portion 11a when seated on the seat portion 11a. This prevents damage or deformation of the seat portion 11a, resulting in improved seating properties when the valve portion 22 seats on the seat portion 11a.

[0032] Although the annular groove 21 a is formed on the outer peripheral surface of the main body 21 of the pilot poppet 20, the annular groove 21 a may alternatively be formed on the inner peripheral surface of the accommodation hole 7 c. Furthermore, although the first notch 21 b and the second notch 21 c are formed on the outer peripheral surface of the main body 21 of the pilot poppet 20, the first notch 21 b and the second notch 21 c may alternatively be formed as grooves in the axial direction on the inner peripheral surface of the accommodation hole 7 c.

[0033] 1, a spring 81 is provided between the flange portion 51a of the pilot piston 51 and the sleeve 7, and a spring 82 is provided between the suction poppet 3 and the connecting member 90. The spring 81 urges the pilot piston 51 so that the flange portion 51a abuts against the main body portion 50 of the main poppet 5, and also urges the main body portion 50 via the flange portion 51a so that the main body portion 50 seats on the seat portion 3f of the suction poppet 3. Meanwhile, the spring 82 urges the suction poppet 3 so that the corner portion 3c of the suction poppet 3 seats on the seat portion 1a of the equipment main body 1.

[0034] Next, the solenoid portion S will be described with reference to FIGS.

[0035] The solenoid section S has a plunger 72 slidably accommodated within the solenoid housing 71, a rod 73 fixed to the plunger 72 and having a tip that abuts against the pilot poppet 20, a spring 74 as a biasing member that is engaged within the solenoid housing 71 and biases the plunger 72 toward the pilot poppet 20, a coil 75 that is accommodated in the solenoid housing 71 and applies a reaction force to the plunger 72 that opposes the biasing force of the spring 74, and a plunger chamber 76 that is provided on the inner periphery of the coil 75 and accommodates the plunger 72.

[0036] The solenoid housing 71 is a cylindrical member with a bottom, in which an accommodation hole 71 c for accommodating the plunger 72 is formed with an opening on the end 71 a side, and the end 71 a side is connected to the connecting member 90 .

[0037] The biasing force of the spring 74 acts to bias the pilot poppet 20 in the valve closing direction via the plunger 72 and the rod 73 fixed to the plunger 72. In other words, the spring 74 biases the pilot poppet 20 so that the valve portion 22 of the pilot poppet 20 is seated on the seat portion 11 a.

[0038] When a current is applied to the coil 75, a magnetic field is generated, which applies a thrust to the plunger 72 that counteracts the biasing force of the spring 74. As the current applied to the coil 75 increases, the thrust that counteracts the biasing force of the spring 74 increases. This reduces the biasing force of the spring 74 that acts on the pilot poppet 20 via the plunger 72 and the rod 73. As a result, the pressure required to separate the valve portion 22 of the pilot poppet 20 from the seat portion 11a, known as the cracking pressure, decreases. In the electromagnetic relief valve 100, the set pressure (relief pressure) at which the pilot poppet 20 opens can be changed by controlling the current applied to the coil 75 to change the biasing force of the spring 74 acting on the pilot poppet 20.

[0039] The plunger chamber 76 is formed by an accommodation hole 71c that accommodates the plunger 72, and a spring chamber 77 that is formed continuous with the accommodation hole 71c and serves as a biasing member chamber in which the spring 74 is accommodated.

[0040] The connecting member 90 is a cylindrical member that connects the housing 2 and the solenoid housing 71. The connecting member 90 has a first connecting portion 90a to which the housing 2 is connected, a second connecting portion 90b to which the solenoid housing 71 is connected, an accommodating hole 90c provided inside the first connecting portion 90a, a communication hole 90d that communicates with the accommodating hole 90c and axially penetrates the inside of the second connecting portion 90b, and an annular protrusion 90e that protrudes radially inward from the inner circumferential surface of the communication hole 90d. The base end 7b of the sleeve 7 is connected to the accommodating hole 90c, and a portion of the pilot poppet 20 that protrudes from the sleeve 7 is accommodated in the accommodating hole 90c. When the solenoid housing 71 is connected to the connecting member 90, a rod 73 is inserted into the communication hole 90d.

[0041] The spring chamber 77 formed in the solenoid housing 71 communicates with the low-pressure passage L through the through hole 72a that penetrates the plunger 72 in the axial direction, the communication hole 90d and the accommodating hole 90c (space SP) of the connecting member 90, the passage defined by the inner surface of the accommodating hole 7c and the second notch 21c, the annular groove 21a, the drain passage 13, and the gap 14.

[0042] A throttle member 60 is provided within the communication hole 90d of the connecting member 90, forming an annular throttle C between itself and the outer circumferential surface of the rod 73. The throttle member 60 has a cylindrical main body portion 60a that fits within the communication hole 90d and a cylindrical reduced-diameter portion 60b that protrudes radially inward from the main body portion 60a. The throttle member 60 is inserted into the communication hole 90d so as to abut against the side surface of the protruding portion 90e. The throttle member 60 and the connecting member 90 also function as a partition member that separates the valve body chamber VS and the plunger chamber 76 formed within the valve housing (the housing 2 and the solenoid housing 71). The throttle member 60 corresponds to the "partition member" and "first partition member" in the claims, and the connecting member 90 corresponds to the "partition member" and "second partition member" in the claims.

[0043] It is preferable that a seal is provided between the communication hole 90d and the throttle member 60. For example, it is preferable that the side surface of the protrusion 90e and the end face of the throttle member 60 form a face seal, or that a separate seal member be provided between the side surface of the protrusion 90e and the end face of the throttle member 60.

[0044] The rod 73 has a fixed portion 73a fixed to the plunger 72, a connecting portion 73b provided contiguous with the fixed portion 73a and having a smaller diameter than the fixed portion 73a, and a through portion 73c provided contiguous with the connecting portion 73b and having a smaller diameter than the connecting portion 73b. The through portion 73c is inserted through a through hole 60d (see FIG. 2) formed in the reduced diameter portion 60b, and is formed so that its tip is located closer to the valve body chamber VS (space SP) than the reduced diameter portion 60b.

[0045] Next, the operation of the electromagnetic relief valve 100 will be described.

[0046] The hydraulic oil in the high-pressure passage H is led to the first communication passage P1 through the pilot passage 10 and the back pressure chamber 8. When the pressure of the hydraulic oil led to the first communication passage P1 reaches the set pressure (cracking pressure) of the pilot poppet 20 set by the solenoid section S, the pressure of the hydraulic oil causes the valve section 22 of the pilot poppet 20 to separate from the seat section 11a.

[0047] When the valve portion 22 of the pilot poppet 20 leaves the seat portion 11a, the hydraulic oil in the back pressure chamber 8 is discharged to the low pressure passage L through the first communication passage P1, the gap between the valve portion 22 and the seat portion 11a, and the low pressure side passage LP.

[0048] The back pressure chamber 8 is constantly supplied with hydraulic oil from the high pressure passage H through the pilot passage 10. However, the supply of hydraulic oil from the high pressure passage H to the back pressure chamber 8 is limited by a throttle provided in the pilot passage 10. Therefore, when the valve element 22 leaves the seat portion 11a and the hydraulic oil in the back pressure chamber 8 is discharged, the pressure in the back pressure chamber 8 gradually becomes lower than the pressure in the high pressure passage H.

[0049] In this way, when the pressure in the back pressure chamber 8 decreases, the biasing force due to the pressure in the back pressure chamber 8 that acts in a direction to seat the body 50 of the main poppet 5 on the seat 3f of the suction poppet 3 decreases. Then, when the pressure difference between the pressure in the back pressure chamber 8 and the pressure in the high pressure passage H exceeds a preset pressure difference, the body 50 of the main poppet 5 lifts off the seat 3f of the suction poppet 3, and the main poppet 5 opens. This allows hydraulic oil to be discharged from the high pressure passage H to the low pressure passage L, preventing the pressure in the high pressure passage H from becoming abnormally high.

[0050] Incidentally, while the electromagnetic relief valve 100 configured as described above is being transported, air may get mixed into the electromagnetic relief valve 100. In the inverse proportional type electromagnetic relief valve 100 of this embodiment, in which the set pressure (relief pressure) increases as the amount of current flowing through the coil 75 increases, when the pilot poppet 20 opens and moves during relief operation, the plunger 72 moves accordingly, and the volume of the spring chamber 77 decreases.

[0051] At this time, hydraulic oil is discharged from the high-pressure passage H to the low-pressure passage L, which may increase the pressure of the hydraulic oil in the low-pressure passage L. When the pressure of the hydraulic oil in the low-pressure passage L is transmitted to the valve body chamber VS through the low-pressure passage LP, the hydraulic oil with increased pressure also acts on the end face 72b of the plunger 72 through the communication hole 90d of the connecting member 90, causing the plunger 72 to move toward the spring chamber 77. In this way, if air remains in the spring chamber 77 when the plunger 72 moves toward the spring chamber 77, the air will be crushed, causing the plunger 72 to move excessively. In other words, if air remains in the spring chamber 77, the air will expand and contract as the plunger 72 moves, causing a mismatch between pressure fluctuations and the operation of the plunger 72, which may cause the operation of the electromagnetic relief valve 100 to become unstable.

[0052] Therefore, in this embodiment, an annular restrictor C is provided in the communication hole 90d that communicates between the valve body chamber VS and the plunger chamber 76. As a result, even if the pressure in the low-pressure side passage LP fluctuates, the restrictor C can suppress the pressure fluctuations in the low-pressure side passage LP from propagating to the plunger chamber 76. When the propagation of pressure fluctuations is suppressed in this way, fluctuations in the pressure acting on the end face 72b of the plunger 72 can be suppressed. As a result, fluctuations in the pressure acting on the end face 72b of the plunger 72 can be suppressed.

[0053] Furthermore, pressure fluctuations in the low-pressure passage LP are prevented from propagating to the plunger chamber 76 by the restriction C, but they still act on the through-hole 73c of the rod 73. In this embodiment, by making the diameter of the through-hole 73c of the rod 73 smaller than the diameter of the fixed portion 73a of the rod 73, in other words, by minimizing the pressure-receiving area of ​​the through-hole 73c of the rod 73 on which the pressure fluctuations in the low-pressure passage LP act, it is possible to reduce fluctuations in thrust due to pressure fluctuations acting on the plunger 72.

[0054] Therefore, according to the electromagnetic relief valve 100 of this embodiment, it is possible to minimize the effects of pressure fluctuations by making the diameter of the through portion 73c of the rod 73 smaller than the diameter of the fixed portion 73a of the rod 73. It is preferable that the diameter of the through portion 73c of the rod 73 be as small as possible within a range that ensures the strength to continue to press the pilot poppet 20.

[0055] Furthermore, for example, when the flow path cross-sectional area of ​​the annular restrictor C is set to a predetermined size, if the diameter of the through-hole 73c is small, the difference with the inner diameter of the reduced diameter portion 60b, i.e., the radial clearance with the annular restrictor C, can be made larger than when the diameter of the through-hole 73c is large. This makes it possible to increase the tolerance for processing or assembly errors, such as misalignment of the central axes of the through-hole 73c and the reduced diameter portion 60b.

[0056] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0057] The electromagnetic relief valve 100 includes a pilot poppet 20 (valve element) that connects or disconnects a high-pressure side passage HP (first communication passage P1) and a low-pressure side passage LP, a valve element chamber VS that connects to the low-pressure side passage LP and accommodates the pilot poppet 20 (valve element), and a solenoid section S that urges the pilot poppet 20 (valve element) in a valve-closing direction. The solenoid section S includes a plunger 72, a rod 73 that is fixed to the plunger 72 and has a tip that extends to the valve element chamber VS and abuts against the pilot poppet 20 (valve element), and a spring 74 that urges the pilot poppet 20 (valve element) in a valve-closing direction via the rod 73. The valve element valve 72 has a spring 74 (biasing member), a coil 75 which generates a magnetic field when a current is applied, and applies a reaction force to the plunger 72 that opposes the biasing force of the spring 74 (biasing member), and a plunger chamber 76 which is provided inside the coil 75 and which houses the plunger 72, and between the valve element chamber VS and the plunger chamber 76 is provided a partition member (throttle member 60 and connecting member 90) which separates the valve element chamber VS from the plunger chamber 76 and has a through hole 60d through which the rod 73 passes, and an annular throttle C is provided between the inner surface of the through hole 60d of the partition member (throttle member 60 and connecting member 90) and the outer surface of the rod 73.

[0058] In this configuration, the annular restriction C is provided between the valve chamber VS and the plunger chamber 76, so when the pressure in the low-pressure passage LP fluctuates, the pressure fluctuation can be prevented from propagating from the valve chamber VS to the plunger chamber 76. As a result, even if air gets into the spring chamber 77, the electromagnetic relief valve 100 can operate stably.

[0059] Furthermore, in the electromagnetic relief valve 100, the rod 73 has a fixed portion 73a that is fixed to the plunger 72, and a through portion 73c that is formed with a smaller diameter than the fixed portion 73a and that passes through the through hole 60d.

[0060] In this configuration, by forming the through-hole 73c of the rod 73 with a smaller diameter, it is possible to increase the clearance between the inner peripheral surface of the through-hole 60d of the partition member (throttle member 60) and the outer peripheral surface of the rod 73, compared to when an annular throttle with the same flow path cross-sectional area is formed using a rod with a larger diameter. This allows for a larger tolerance for processing and assembly, thereby improving productivity and reducing production costs.

[0061] The electromagnetic relief valve 100 further includes a housing 2 and a solenoid housing 71 (valve housing) in which a valve body chamber VS and a plunger chamber 76 are formed, and the partition member includes a throttling member 60 (first partition member) having a through hole 60d formed therein, and a connecting member 90 (second partition member) that supports the throttling member 60 (first partition member) and is attached to the housing 2 and the solenoid housing 71 (valve housing).

[0062] In this configuration, the through hole 60d, which requires high machining accuracy, and the other portions are made of separate members, thereby reducing costs.

[0063] Furthermore, in the electromagnetic relief valve 100, the gap between the throttle member 60 (first partition member) and the connecting member 90 (second partition member) is sealed.

[0064] In this configuration, leakage between the throttle member 60 (first partition member) and the connecting member 90 (second partition member) is eliminated, and the fluid passes only through the annular throttle C. This makes it possible to suppress the effect of leakage on the operation of the electromagnetic relief valve 100.

[0065] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0066] For example, the throttle member 60 and the connecting member 90 may be integrated. In addition, in the above embodiment, the connecting portion 73b is provided between the fixing portion 73a and the through portion 73c, but the connecting portion 73b does not necessarily have to be provided.

[0067] Furthermore, in the above embodiment, the electromagnetic relief valve 100 is described as being provided with the suction poppet 3, but it is not necessary for the electromagnetic relief valve 100 to be provided with the suction poppet 3.

[0068] In the above embodiment, the connecting member 90 connecting the housing 2 and the solenoid housing 71 is the second partition member, but this is not limiting. For example, a member fixed to only one of the housing 2 and the solenoid housing 71 may be used as the partition member.

[0069] This application claims priority based on Japanese Patent Application No. 2024-7365, filed with the Japan Patent Office on January 22, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. An electromagnetic relief valve of an inverse proportion type, comprising: a valve body that communicates or blocks a high-pressure side passage and a low-pressure side passage; a valve body chamber that communicates with the low-pressure side passage and houses the valve body; and a solenoid unit that biases the valve body in a valve closing direction, wherein the solenoid unit includes: a plunger; a rod fixed to the plunger, with a tip extending to the valve body chamber and contacting the valve body; a biasing member that biases the valve body in the valve closing direction via the rod; a coil that generates a magnetic field when an electric current is applied and applies a reaction force opposing the biasing force of the biasing member to the plunger; and a plunger chamber provided inside the coil and housing the plunger, and between the valve body chamber and the plunger chamber, a partitioning member having a through hole that partitions the valve body chamber and the plunger chamber and through which the rod passes is provided, and an annular throttle is provided between an inner peripheral surface of the through hole of the partitioning member and an outer peripheral surface of the rod.

2. The electromagnetic relief valve according to claim 1, wherein the rod has: a fixed portion fixed to the plunger; and a through portion formed to have a smaller diameter than the fixed portion and passing through the through hole.

3. The electromagnetic relief valve according to claim 1 or 2, further comprising a valve housing in which the valve body chamber and the plunger chamber are formed inside, and the partitioning member has: a first partitioning member in which the through hole is formed; and a second partitioning member that supports the first partitioning member and is attached to the valve housing.

4. The electromagnetic relief valve according to claim 3, wherein a space between the first partitioning member and the second partitioning member is sealed.

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