Solenoid relief valve

Abstract

To provide a solenoid relief valve which stably operates even when air is mixed into the solenoid relief valve.SOLUTION: A solenoid relief valve 100 includes a pilot poppet 20 for communicating or cutting off a high pressure side passage HP and a low pressure side passage LP with or from each other, a valve element chest VS storing the pilot poppet 20, and a solenoid part S for energizing the pilot poppet 20 in a valve closing direction, the solenoid part S having a plunger 72, a rod 73, a spring 74 for energizing the pilot poppet 20 in the valve closing direction, and a plunger chamber 76 storing the plunger 72. Between the valve element chest VS and the plunger chamber 76, a partition member 90 is provided for separating between the valve element chest VS and the plunger chamber 76 and has a through-hole 60d where the rod 73 passes. Between the through-hole 60d of the partition member 90 and the rod 73, an annular restriction C is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 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 Patent Document 1 includes a solenoid portion that enables the set pressure to be changed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-12406 Summary of the Invention [Problem to be solved by the invention]

[0005] The electromagnetic relief valve described in Patent Document 1 is inspected before shipping, then transported and 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.

[0006] 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 could result in unstable operation of the electromagnetic relief valve.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a solenoid relief valve that operates stably even when air enters the solenoid relief valve.

Means for Solving the Problems

[0008] The present invention is an inverse proportional type solenoid relief valve, comprising: a valve body that communicates or shuts off 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 the valve closing direction. The solenoid unit includes a plunger, a rod fixed to the plunger and having a tip extending to the valve body chamber and abutting against 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 a current is applied and imparts 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. A partition member having a through hole that partitions the valve body chamber and the plunger chamber and through which the rod passes is provided between the valve body chamber and the plunger chamber, and an annular throttle is provided between the inner peripheral surface of the through hole of the partition member and the outer peripheral surface of the rod.

[0009] In this invention, since an annular throttle is provided between the valve body chamber and the plunger chamber, when the pressure in the low-pressure side passage fluctuates, the propagation of the pressure fluctuation of the fluid from the valve body chamber to the plunger chamber is suppressed, and the operation of the plunger can be prevented from becoming unstable.

[0010] Further, the present invention is characterized in that the rod has a fixed portion fixed to the plunger and a through portion formed with a smaller diameter than the fixed portion and passing through the through hole.

[0011] In this invention, by forming the through portion of the rod constituting the annular throttle to have a smaller diameter, the clearance between the inner peripheral surface of the through hole of the partition member and the outer peripheral surface of the rod can be increased compared to the case where the annular throttle with the same flow path cross-sectional area is formed by a rod with a larger diameter. Thereby, the allowable error in processing and assembly can be increased, so that productivity can be improved and production costs can be reduced.

[0012] Furthermore, the present invention further includes a valve housing in which a valve body chamber and a plunger chamber are formed inside, and the partition member has a first partition member in which a through hole is formed, and a second partition member that supports the first partition member and is attached to the valve housing.

[0013] In this invention, by configuring the through hole that requires machining accuracy and other parts with separate members, the cost can be reduced.

[0014] Moreover, the present invention is characterized in that the space between the first partition member and the second partition member is sealed.

[0015] In this invention, leakage between the first partition member and the second partition member is eliminated, and the fluid only passes through the annular throttle. Thereby, the influence on the operation of the electromagnetic relief valve due to leakage can be suppressed.

Advantages of the Invention

[0016] According to the present invention, an electromagnetic relief valve that operates stably even when air is mixed in can be provided.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0018] With reference to FIGS. 1 and 2, the electromagnetic relief valve 100 according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of the electromagnetic relief valve 100 according to the present embodiment. FIG. 2 is an enlarged cross-sectional view near the annular throttle C of the electromagnetic relief valve 100 according to the present embodiment.

[0019] The electromagnetic relief valve 100 is an inverse proportional type electromagnetic relief valve. The inverse proportional type means a relief valve configured such that the higher the current value applied to the solenoid described later, the lower the relief pressure.

[0020] When the pressure of the hydraulic oil in the high-pressure passage H reaches the set pressure (relief pressure), the electromagnetic relief valve 100 opens, and by discharging the hydraulic oil from the high-pressure passage H to the low-pressure passage L, it prevents the pressure of the hydraulic oil in the high-pressure passage H from becoming abnormally high. Further, the electromagnetic relief valve 100 has an anti-cavitation function, and when the high-pressure passage H becomes negative pressure, it opens and supplies hydraulic oil from the low-pressure passage L to the high-pressure passage H to prevent the occurrence of cavitation.

[0021] As shown in FIG. 1, the electromagnetic relief valve 100 is attached to the equipment main body 1 by screw fastening. The equipment main 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 the present embodiment, the case where hydraulic oil is used as the working fluid of the equipment main body 1 will be described as an example, but the working fluid may be other liquids such as working water.

[0022] In the equipment main body 1, a high-pressure passage H and a low-pressure passage L are provided with the electromagnetic relief valve 100 as a boundary. In the equipment main body 1, a seat portion 1a as a first valve seat on which a suction poppet 3 described later seats is provided between the high-pressure passage H and the low-pressure passage L. Note that the equipment main body 1 is not limited to the main body of a hydraulic device, and may be a block body installed between each hydraulic device.

[0023] As shown in FIG. 1, the electromagnetic relief valve 100 includes a valve portion V for communicating or blocking the high-pressure passage H and the low-pressure passage L, and a solenoid portion S for adjusting the set pressure (relief pressure).

[0024] As shown in Fig. 1, the valve unit V includes a housing 2 attached to the equipment main body 1 where 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 configured to communicate or cut off the high-pressure passage H and the low-pressure passage L by separating from or seating on the seat portion 1a, a main poppet 5 as a second valve body provided in the suction poppet 3 and configured to communicate or cut off the high-pressure passage H and the low-pressure passage L by separating from or seating on the seat portion 3f as a second valve seat formed on the suction poppet 3, a back-pressure chamber 8 in the suction poppet 3 into which hydraulic oil for urging the main poppet 5 in the valve-closed direction from the high-pressure passage H is introduced, a sleeve 7 partitioning the back-pressure chamber 8 from the main poppet 5, a pilot passage 10 provided in the main poppet 5 and communicating the high-pressure passage H and the back-pressure chamber 8, a drain chamber 12 provided in the sleeve 7 where the hydraulic oil in the back-pressure chamber 8 is discharged, a first communication passage P1 provided in the sleeve 7 and communicating the drain chamber 12 and the back-pressure chamber 8, and a pilot poppet 20 as a third valve body provided in the sleeve 7 and opening and closing the first communication passage P1.

[0025] As shown in Fig. 1, the housing 2 is a cylindrical member having a first cylindrical portion 2a attached to the equipment main body 1 and a second cylindrical portion 2b coupled to a connecting member 90 on the side opposite to the first cylindrical portion 2a. The housing 2 is connected to the solenoid housing 71 of the solenoid unit S by the connecting member 90. The housing 2 and the solenoid housing 71 of the present embodiment correspond to the "valve housing" in the claims.

[0026] The suction poppet 3 is a member formed in a bottomed cylindrical shape having a cylindrical portion 3a and a bottom portion 3b. The suction poppet 3 is provided in the housing 2 so as to be axially movable, and a part thereof protrudes 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.

[0027] The corner 3c between the cylindrical portion 3a and the bottom portion 3b of the suction poppet 3 is formed in a tapered shape. When this corner 3c seats on the seat portion 1a of the device body 1, the communication between the high-pressure passage H and the low-pressure passage L through the space between the device body 1 and the suction poppet 3 is blocked. On the bottom portion 3b side of the suction poppet 3, a first accommodation hole 3d for accommodating the main poppet 5 is provided, and at the end opposite to the bottom portion 3b, a second accommodation hole 3e with a diameter larger than that of the first accommodation hole 3d and for accommodating the sleeve 7 is provided.

[0028] The main poppet 5 has a main body portion 50 slidable within the first accommodation hole 3d and a pilot piston 51 slidable within a sliding hole 50a formed axially through the main body portion 50.

[0029] The main body portion 50 has a valve portion 50b that seats on a seat portion 3f formed inside the corner 3c of the suction poppet 3. When the valve portion 50b seats on the seat portion 3f, the 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 sealing member (O-ring) for sealing the gap between the outer peripheral surface of the main body portion 50 and the inner peripheral surface of the suction poppet 3 is provided.

[0030] The pilot piston 51 has a flange portion 51a provided facing a back pressure chamber 8 which is a space defined by the inner peripheral 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 sliding 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. Further, a pilot passage 10 for communicating the high-pressure passage H and the back pressure chamber 8 is provided in the pilot piston 51. A throttle for imparting resistance to the hydraulic oil flowing through the pilot passage 10 is provided in the pilot passage 10.

[0031] The sleeve 7 has a tip portion 7a inserted into the suction poppet 3, a base end portion 7b coupled to the connecting member 90, a receiving hole 7c opening at an axial end opposite to the tip portion 7a, and an intermediate portion 7d provided between the tip portion 7a and the base end portion 7b and having an outer peripheral surface exposed between the suction poppet 3 and the connecting member 90. The sleeve 7 slidably supports the suction poppet 3 at the tip portion 7a. A sealing member (O-ring) for sealing the gap between the sleeve 7 and the suction poppet 3 is provided between the outer peripheral surface of the tip portion 7a of the sleeve 7 and the inner peripheral surface of the suction poppet 3.

[0032] Further, in the sleeve 7, a first communication passage P1 having one end opening to the back pressure chamber 8 and the other end opening to the bottom surface of the receiving hole 7c and communicating the back pressure chamber 8 and the receiving hole 7c, and a drain passage 13 having one end opening to the inner peripheral surface of the receiving hole 7c and the other end opening to the outer peripheral surface of the intermediate portion 7d are formed.

[0033] A seat portion 11a on which the valve portion 22 of the pilot poppet 20 seats and departs is provided at the opening end of the first communication passage P1 opening to the receiving hole 7c. The seat portion 11a is formed coaxially with the receiving hole 7c so that its central axis coincides with the central axis of the receiving hole 7c. Further, a throttle 11b for providing resistance to the flow of the hydraulic oil flowing through the first communication passage P1 is provided on the first communication passage P1 between the seat portion 11a and the back pressure chamber 8. In the present embodiment, the first communication passage P1 corresponds to the "high-pressure side passage HP" in the claims.

[0034] The drain chamber 12 is a space partitioned by the receiving hole 7c and the pilot poppet 20.

[0035] The drain passage 13 is always 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 the present embodiment, the drain chamber 12 and the passage from the drain chamber 12 to the low-pressure passage L correspond to the "low-pressure side passage LP" in the claims.

[0036] As shown in FIG. 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 valve portion 22 formed in a conical shape protruding axially from the main body portion 21.

[0037] An annular groove 21a formed so as to always communicate with the drain passage 13, a first notch portion 21b formed along the axial direction from the annular groove 21a toward the valve portion 22 side, and a second notch portion 21c formed along the axial direction from the annular groove 21a toward the solenoid portion S side are provided in the main body portion 21 of the pilot poppet 20.

[0038] The first notch portion 21b is formed by notching the outer peripheral surface of the main body portion 21 in a planar shape. The drain chamber 12 communicates with the low-pressure passage L through a passage partitioned by the inner peripheral surface of the accommodation hole 7c and the first notch portion 21b, the annular groove 21a, the drain passage 13, and the gap 14. The passage partitioned by the inner peripheral surface of the accommodation hole 7c and the first notch portion 21b also functions as a first throttle that imparts resistance to the hydraulic oil discharged from the back pressure chamber 8 to the low-pressure passage L.

[0039] Further, the second notch portion 21c is formed by notching the outer peripheral surface of the main body portion 21 in a planar shape along the axial direction from the annular groove 21a toward the solenoid portion S side so that the end portion on the solenoid portion S side is always exposed from the accommodation hole 7c. The space SP in the accommodation 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 partitioned by the inner peripheral surface of the accommodation hole 7c and the second notch portion 21c, the annular groove 21a, the drain passage 13, and the gap 14. Hereinafter, the space formed by the accommodation hole 7c of the sleeve 7, the space SP, and the region on the space SP side of the reduced diameter portion 60e in the communication hole 90d is referred to as a valve body chamber VS that accommodates the pilot poppet 20.

[0040] The pilot poppet 20 formed in this way is slidably supported by a housing hole 7c formed coaxially with the seat portion 11a. That is, the pilot poppet 20 is supported by the housing hole 7c so that its central axis does not incline with respect to the central axis of the seat portion 11a. In this way, by suppressing the state in which the pilot poppet 20 inclines with respect to the seat portion 11a, it is possible to prevent the valve portion 22 from hitting the seat portion 11a on one side when the valve portion 22 seats on the seat portion 11a. As a result, it is possible to suppress the seat portion 11a from being damaged or deformed, and as a result, it is possible to improve the seating performance when the valve portion 22 seats on the seat portion 11a.

[0041] The annular groove 21a is formed on the outer peripheral surface of the main body portion 21 of the pilot poppet 20. Instead of this, the annular groove 21a may be formed on the inner peripheral surface of the housing hole 7c. Further, the first notch portion 21b and the second notch portion 21c are formed on the outer peripheral surface of the main body portion 21 of the pilot poppet 20. Instead of this, the first notch portion 21b and the second notch portion 21c may be formed in a groove shape in the axial direction on the inner peripheral surface of the housing hole 7c.

[0042] As shown in FIG. 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 biases the pilot piston 51 so that the flange portion 51a abuts against the main body portion 50 of the main poppet 5, and biases 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. On the other hand, the spring 82 biases the suction poppet 3 so that the corner portion 3c of the suction poppet 3 seats on the seat portion 1a of the device main body 1.

[0043] Subsequently, with reference to FIGS. 1 and 2, the solenoid portion S will be described.

[0044] The solenoid unit S includes a plunger 72 slidably accommodated in a solenoid housing 71, a rod 73 fixed to the plunger 72 and having a tip that abuts against a pilot poppet 20, a spring 74 serving as a biasing member that is locked in the solenoid housing 71 and biases the plunger 72 toward the pilot poppet 20, a coil 75 accommodated in the solenoid housing 71 and applying a reaction force against the biasing force of the spring 74 to the plunger 72, and a plunger chamber 76 provided on the inner peripheral side of the coil 75 and accommodating the plunger 72.

[0045] The solenoid housing 71 is a bottomed cylindrical member in which an accommodation hole 71c for accommodating the plunger 72 is formed to open on the end 71a side, and the end 71a side is coupled to a connecting member 90.

[0046] 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. That is, the spring 74 biases the pilot poppet 20 so that the valve portion 22 of the pilot poppet 20 seats on the seat portion 11a.

[0047] When an electric current is applied to the coil 75, a magnetic field is generated, and a thrust opposing the biasing force of the spring 74 is applied to the plunger 72. As the electric current applied to the coil 75 increases, the thrust opposing the biasing force of the spring 74 increases. As a result, the biasing force of the spring 74 acting on the pilot poppet 20 via the plunger 72 and the rod 73 decreases. Consequently, the pressure required to separate the valve portion 22 of the pilot poppet 20 from the seat portion 11a, so-called 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 electric current applied to the coil 75 to change the biasing force of the spring 74 acting on the pilot poppet 20.

[0048] The plunger chamber 76 is formed by a housing hole 71c that houses the plunger 72, and a spring chamber 77 that is formed continuously with the housing hole 71c and serves as a biasing member chamber that houses the spring 74.

[0049] The connecting member 90 is a cylindrically formed member that connects the housing 2 and the solenoid housing 71. The connecting member 90 includes a first coupling portion 90a to which the housing 2 is coupled, a second coupling portion 90b to which the solenoid housing 71 is coupled, a housing hole 90c provided inside the first coupling portion 90a, a communication hole 90d that communicates with the housing hole 90c and axially penetrates the inside of the second coupling portion 90b, and an annular protruding portion 90e that protrudes radially inward from the inner peripheral surface of the communication hole 90d. The base end portion 7b of the sleeve 7 is coupled to the housing hole 90c, and a part of the pilot poppet 20 protruding from the sleeve 7 is housed therein. Further, in a state where the solenoid housing 71 is coupled to the connecting member 90, the rod 73 is inserted into the communication hole 90d.

[0050] The spring chamber 77 formed in the solenoid housing 71 communicates with the low-pressure passage L through a through-hole 72a that axially penetrates the plunger 72, the communication hole 90d and the housing hole 90c (space SP) of the connecting member 90, a passage partitioned by the inner peripheral surface of the housing hole 7c and the second notch portion 21c, an annular groove 21a, a drain passage 13, and a gap 14.

[0051] In the communication hole 90d of the connecting member 90, a throttle member 60 is provided that forms an annular throttle C with the outer peripheral surface of the rod 73. The throttle member 60 has a cylindrical main body portion 60a that fits into the communication hole 90d, and a cylindrical reduced-diameter portion 60b formed so as to project 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 partitions the valve body chamber VS and the plunger chamber 76 formed in the valve housing (housing 2 and solenoid housing 71). Note that the throttle member 60 corresponds to the "partition member" and the "first partition member" in the claims, and the connecting member 90 corresponds to the "partition member" and the "second partition member" in the claims.

[0052] It is preferable that the space between the communication hole 90d and the throttle member 60 is sealed. For example, it is preferable that the side surface of the protruding portion 90e and the end surface of the throttle member 60 form a surface seal, or that a separate seal member is provided between the side surface of the protruding portion 90e and the end surface of the throttle member 60.

[0053] The rod 73 has a fixing portion 73a fixed to the plunger 72, a connecting portion 73b provided continuously to the fixing portion 73a and having a smaller diameter than the fixing portion 73a, and a through portion 73c provided continuously to 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 its tip is formed so as to be located on the valve body chamber VS (space SP) side of the reduced-diameter portion 60b.

[0054] Next, the operation of the electromagnetic relief valve 100 will be described.

[0055] The hydraulic oil in the high-pressure passage H is guided to the first communication passage P1 through the pilot passage 10 and the back pressure chamber 8. When the pressure of the hydraulic oil guided to the first communication passage P1 reaches the set pressure (cracking pressure) of the pilot poppet 20 set by the solenoid portion S, the valve portion 22 of the pilot poppet 20 is separated from the seat portion 11a by the pressure of the hydraulic oil.

[0056] When the valve portion 22 of the pilot poppet 20 separates from 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 passage LP on the low pressure side.

[0057] Hydraulic oil is constantly supplied to the back pressure chamber 8 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 restricted by the throttle provided in the pilot passage 10. For this reason, when the valve portion 22 separates from 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.

[0058] 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 the direction of seating the main body portion 50 of the main poppet 5 on the seat portion 3f of the suction poppet 3 decreases. And 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 main body portion 50 of the main poppet 5 separates from the seat portion 3f of the suction poppet 3, and the main poppet 5 opens. As a result, the hydraulic oil is discharged from the high pressure passage H to the low pressure passage L, and it is prevented that the pressure in the high pressure passage H becomes abnormally high.

[0059] By the way, air may be mixed into the electromagnetic relief valve 100 while transporting the electromagnetic relief valve 100 configured in this way. In the inverse proportional type electromagnetic relief valve 100 in which the set pressure (relief pressure) increases as the amount of current flowing through the coil 75 increases as in this embodiment, when the pilot poppet 20 opens and moves during the relief operation, the plunger 72 moves accordingly and the volume of the spring chamber 77 decreases.

[0060] At this time, when the hydraulic oil is discharged from the high-pressure passage H to the low-pressure passage L, the pressure of the hydraulic oil in the low-pressure passage L may increase. When the pressure of the hydraulic oil in the low-pressure passage L propagates to the valve body chamber VS through the low-pressure side passage LP, the increased-pressure hydraulic oil 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 side. In this way, when the plunger 72 moves toward the spring chamber 77 side, if air stays in the spring chamber 77, the air will be compressed, and the plunger 72 may move excessively. That is, if air stays in the spring chamber 77, as the plunger 72 moves, the air expands and contracts, resulting in a deviation between the pressure fluctuation and the operation of the plunger 72, and the operation of the electromagnetic relief valve 100 may become unstable.

[0061] Therefore, in this embodiment, an annular throttle C is provided in the communication hole 90d that communicates the valve body chamber VS and the plunger chamber 76. Thereby, even if the pressure of the low-pressure side passage LP fluctuates, the throttle C can suppress the propagation of the pressure fluctuation of the low-pressure side passage LP to the plunger chamber 76. In this way, when the propagation of the pressure fluctuation is suppressed, the fluctuation of the pressure acting on the end face 72b of the plunger 72 can be suppressed. Thereby, the fluctuation of the pressure acting on the end face 72b of the plunger 72 can be suppressed.

[0062] Also, although the pressure fluctuation of the low-pressure side passage LP is suppressed from propagating to the plunger chamber 76 by the throttle C, it acts on the through portion 73c of the rod 73. As in this embodiment, by making the through portion 73c of the rod 73 smaller than the diameter of the fixed portion 73a of the rod 73, that is, by minimizing the pressure receiving area of the through portion 73c of the rod 73 on which the pressure fluctuation of the low-pressure side passage LP acts, the fluctuation of the thrust based on the pressure fluctuation acting on the plunger 72 can be reduced.

[0063] Therefore, according to the electromagnetic relief valve 100 of the present embodiment, by making the through-hole 73c of the rod 73 smaller than the diameter of the fixed portion 73a of the rod 73, the influence of pressure fluctuations can be minimized. Note that the diameter of the through-hole 73c of the rod 73 is preferably as small as possible within the range where the strength to continuously press the pilot poppet 20 can be ensured.

[0064] Also, for example, when the flow path cross-sectional area of the annular throttle C is set to a predetermined size, if the diameter of the through-hole 73c is small, the difference from the inner diameter of the reduced-diameter portion 60b, that is, the radial clearance with the annular throttle C can be made larger than when the diameter of the through-hole 73c is large. Thereby, for example, manufacturing or assembly tolerance errors such as misalignment of the central axes of the through-hole 73c and the reduced-diameter portion 60b can be increased.

[0065] The configuration, operation, and effects of the embodiment of the present invention configured as described above will be collectively described.

[0066] The electromagnetic relief valve 100 includes a pilot poppet 20 (valve body) that connects or blocks a high-pressure side passage HP (first connection passage P1) and a low-pressure side passage LP, a valve body chamber VS that communicates with the low-pressure side passage LP and houses the pilot poppet 20 (valve body), and a solenoid unit S that biases the pilot poppet 20 (valve body) in the valve closing direction. The solenoid unit S includes a plunger 72, a rod 73 that is fixed to the plunger 72 and has a tip extending to the valve body chamber VS and abutting against the pilot poppet 20 (valve body), a spring 74 (biasing member) that biases the pilot poppet 20 (valve body) in the valve closing direction via the rod 73, a coil 75 that generates a magnetic field when an electric current is applied and applies a reaction force opposing the biasing force of the spring 74 (biasing member) to the plunger 72, and a plunger chamber 76 that is provided inside the coil 75 and houses the plunger 72. Between the valve body chamber VS and the plunger chamber 76, a partitioning member (restriction member 60 and connecting 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. An annular restriction C is provided between the inner peripheral surface of the through hole 60d of the partitioning member (restriction member 60 and connecting member 90) and the outer peripheral surface of the rod 73.

[0067] In this configuration, since the annular restriction C is provided between the valve body chamber VS and the plunger chamber 76, when the pressure in the low-pressure side passage LP fluctuates, the propagation of the pressure fluctuation from the valve body chamber VS to the plunger chamber 76 can be suppressed. Thereby, even if air enters the spring chamber 77, the electromagnetic relief valve 100 can operate stably.

[0068] Further, in the electromagnetic relief valve 100, the rod 73 has a fixing portion 73a fixed to the plunger 72 and a through portion 73c formed to have a smaller diameter than the fixing portion 73a and passing through the through hole 60d.

[0069] In this configuration, by forming the through portion 73c of the rod 73 to have a smaller diameter, 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 can be increased compared to the case of forming an annular throttle with the same flow path cross-sectional area using a rod with a larger diameter. As a result, the allowable errors in processing and assembly can be increased, improving productivity and reducing production costs.

[0070] Further, 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 inside, and the partition member includes a throttle member 60 (first partition member) in which a through hole 60d is formed, and a connecting member 90 (second partition member) that supports the throttle member 60 (first partition member) and is attached to the housing 2 and the solenoid housing 71 (valve housing).

[0071] In this configuration, by configuring the through hole 60d that requires machining accuracy and other portions with separate members, the cost can be reduced.

[0072] Also, in the electromagnetic relief valve 100, the space between the throttle member 60 (first partition member) and the connecting member 90 (second partition member) is sealed.

[0073] 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. As a result, the influence of the leakage on the operation of the electromagnetic relief valve 100 can be suppressed.

[0074] As described above, the embodiments of the present invention have been explained. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0075] For example, the throttle member 60 and the connecting member 90 may be integrated. Also, 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.

[0076] Also, in the above embodiment, the case where the electromagnetic relief valve 100 includes the suction poppet 3 has been described as an example, but the suction poppet 3 does not necessarily have to be included.

[0077] In the above embodiment, the case where the connecting member 90 that connects the housing 2 and the solenoid housing 71 is a second partition member has been described as an example, but it is not limited thereto. For example, a member fixed to only one of the housing 2 and the solenoid housing 71 may be used as the partition member.

Description of Reference Numerals

[0078] 100... electromagnetic relief valve, 1... equipment main body, 2... housing (valve housing), 3... suction poppet, 5... main poppet, 7... sleeve, 8... back pressure chamber, 10... pilot passage 12... drain chamber, 13... drain passage, 14... gap, 20... pilot poppet, 60... throttle member (first partition member), 60a... main body portion, 60b... reduced diameter portion, 60d... through hole, 60e... reduced diameter portion, 71... solenoid housing (valve housing), 71c... accommodation hole, 72... plunger, 72a... through hole, 72b... end face, 73... rod, 73a... fixing portion, 73b... connecting portion, 73c... through portion, 74... spring, 75... coil, 76... plunger chamber, 77... spring chamber, 90... connecting member (second partition member), 90c... accommodation hole, 90d... communication hole, 90e... protruding portion C... throttle, H... high pressure passage, HP... passage, L... low pressure passage, S... solenoid portion, SP... space, VS... valve body chamber

Claims

1. An electromagnetic relief valve of an inverse proportion type, a valve body that connects or blocks a passage on the high-pressure side and a passage on the low-pressure side, a valve body chamber that communicates with the passage on the low-pressure side and houses the valve body, and a solenoid unit that biases the valve body in the valve closing direction. The solenoid unit includes a plunger, a rod that is fixed to the plunger and has 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 a current is applied and applies a reaction force opposing the biasing force of the biasing member to the plunger, and a plunger chamber that is provided inside the coil and houses the plunger. Between the valve body chamber and the plunger chamber, a partitioning member is provided that partitions the valve body chamber and the plunger chamber and has a through hole through which the rod passes. An electromagnetic relief valve, characterized in that 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 fixing portion fixed to the plunger, and a through portion formed with a smaller diameter than the fixing 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, wherein 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, characterized in that a space between the first partitioning member and the second partitioning member is sealed.

Images