JP4018659B2 - Relief valve device - Google Patents

Description

  The present invention relates to a relief valve device.

  For example, a hydraulic motor is used as a turning motor and a traveling motor of a construction machine vehicle. The hydraulic motor is driven by hydraulic fluid supplied from a hydraulic supply source. For example, in such a hydraulic circuit having a hydraulic motor and a hydraulic supply source, a relief valve is provided to prevent the hydraulic pressure from becoming too high.

  A conventional relief valve is disclosed in Patent Document 1, for example. In the relief valve, a plunger that is pressed forward by a spring to block the inlet and outlet is moved backward against the elastic recovery force of the spring as the pressure of the inlet exceeds the relief pressure. The piston that communicates with the outflow port and presses the rear end of the spring forward is configured to compress the spring and adjust the relief pressure by moving forward with an increase in pressure at the inflow port. This relief valve has a pressure-boosting function, and is configured so that the relief pressure gradually increases as the primary pressure, which is the inlet pressure, increases, and finally reaches the maximum relief pressure set. Has been. Therefore, by using this relief valve, it is possible to prevent the hydraulic oil pressure in the hydraulic circuit from exceeding the set pressure corresponding to the maximum relief pressure.

Japanese Patent No. 2908435

  In prior art relief valves, the maximum relief pressure is a single set point. Therefore, in the conventional relief valve, the upper limit value of the hydraulic oil pressure in the hydraulic circuit can be set to only one set pressure.

  An object of the present invention is to provide a relief valve device capable of switching and setting a maximum relief pressure to a plurality of set values with a simple operation.

The present invention includes a housing in which a valve passage is formed;
Fluid pressure drive based on the primary pressure, which is displaceable in the opening direction that increases the opening and the closing direction that decreases the opening over the closed position that closes the valve passage and the fully open position that opens the valve passage at the maximum opening A valve body that receives force in the opening direction;
Spring means for pressing the valve body in the closing direction by elastic recovery force;
The spring means is supported and displaced in the deformation direction in which the amount of deformation is increased and the recovery direction in which the amount of deformation is reduced over the minimum position where the amount of deformation of the spring means is minimum and the maximum position where the amount of deformation of the spring means is maximum. A deformation amount adjusting means that is provided in a deformable direction and receives a fluid pressure driving force based on the primary pressure in the deformation direction;
A switching operation is provided between a permissible state in which the displacement of the deformation amount adjusting means is completely allowed and a restricted state in which the displacement of the deformation amount adjusting means is restricted. In the restricted state, the deformation amount adjusting means has a minimum position and a maximum position. And a displacement limiting means for preventing displacement to a maximum position side beyond a limit position set between the relief valve device and the relief valve device.

  According to the present invention, the valve body is pressed in the opening direction by the fluid pressure driving force based on the primary pressure, and is pressed in the closing direction by the elastic recovery force of the spring means. As a result, in the relief valve device, the primary pressure when the fluid pressure driving force received by the valve body and the elastic recovery force are equal is set as the relief pressure, and when the primary pressure exceeds the relief pressure, The body can be displaced in the opening direction to open the valve passage. The spring means for setting the relief pressure is supported by the deformation amount adjusting means, the deformation amount is changed by the displacement of the deformation amount adjusting means, and the generated elastic recovery force is generated. The deformation amount adjusting means receives a fluid pressure driving force based on the primary pressure in the deformation direction, and increases the deformation amount of the spring means as the primary pressure increases. Thus, the relief pressure is set to gradually increase as the primary pressure increases.

  In addition to the configuration having the boosting buffer function, a displacement limiting unit for limiting the displacement of the deformation amount adjusting unit that contributes to the relief pressure setting is provided. The displacement limiting means is provided so that it can be switched between a restricting state in which the displacement of the deformation amount adjusting means is restricted and an allowable state in which the displacement of the deformation amount adjusting means is completely allowed. When the displacement limiting unit is in the allowable state, the deformation amount adjusting unit can be displaced between the minimum position and the maximum position without being limited, and can be displaced to the maximum position. In this permissible state, the movable range of the deformation amount adjusting means is a range extending from the minimum position to the maximum position, and when the deformation amount adjusting means is arranged at the maximum position, the spring means is in the most deformed state, The relief pressure set in this state is the maximum relief pressure. On the other hand, when the displacement restricting means is in the restricted state, the deformation amount adjusting means prevents displacement to the maximum position side beyond the restricting position set between the minimum position and the maximum position. In this restricted state, the movable range of the deformation amount adjusting means is a range extending between the minimum position and the restricted position, and when the deformation amount adjusting means is arranged at the restricted position, the spring means is in the most deformed state, The relief pressure set in this state is the maximum relief pressure. As a result, the maximum relief pressure differs depending on whether the displacement limiting means is in the allowable state or in the limited state.

  Therefore, the maximum relief pressure can be switched by a simple operation of switching the displacement limiting means, and a plurality of maximum relief pressures can be set. Here, the restriction position may be one, but may be plural. When there is one limit position, the maximum relief pressure can be set in two stages. When there are a plurality of restriction positions, three or more stages can be set according to the number.

  Further, the present invention is characterized in that the displacement limiting means can be switched between a limited state and an allowable state by supplying and stopping the supply of pilot fluid.

  According to the present invention, the displacement restricting means can be switched between the restricted state and the permitted state by controlling the supply and stoppage of the pilot fluid. As a result, it is possible to realize a switching operation of the displacement limiting means with a simple configuration and a simple operation of controlling the supply and stop of the pilot fluid.

Further, in the present invention, the deformation amount adjusting means has a locking portion protruding in a direction intersecting the deformation direction and the recovery direction,
The displacement limiting means can be displaced in the protruding direction toward the protruding position and in the retracting direction toward the retracted position over the protruding position for locking the locking portion accompanying the displacement of the deformation amount adjusting means and the retracted position retracted from the protruding position. And is provided with a locking piece that is driven into a state where the locking portion can be locked and a state where the locking portion cannot be locked by supplying and stopping the supply of the pilot fluid.

  According to the present invention, the displacement limiting means is in a state in which the locking piece cannot lock the locking portion in the allowable state. In this state, the locking portion is not locked by the locking piece, and the deformation amount adjusting means can be displaced over the minimum position and the maximum position. Further, the displacement limiting means is in a state where the locking piece can lock the locking portion in the limited state. In this state, the locking portion is locked by the locking piece, and the deformation amount adjusting means is prevented from being displaced beyond the limit position to the maximum position side. In this way, the relief can be switched by the pilot fluid to switch the maximum relief pressure by providing the latching portion on the deformation amount adjusting means and the latching piece driven by the pilot fluid on the displacement limiting means. A valve device can be realized.

  In the present invention, at least one of the locking portion and the locking piece is moved in the retracting direction when the deformation amount adjusting means is displaced in the deformation direction while being locked to each other. A guide surface for guiding the displacement is formed.

  According to the present invention, when the deformation amount adjusting means is displaced in the deformation direction, the locking piece is guided by the guide surface so as to be displaced in the retracting direction. As a result, when switching from the restricted state to the permitted state, even if the locking piece is not displaced in the retracting direction, it is displaced in the retracting direction by the deformation amount adjusting means. Accordingly, the pilot fluid can be driven only in the protruding direction, and the configuration can be simplified.

In the present invention, the locking piece is a rolling element.
According to the present invention, by using the locking piece that is a rolling element, the locking piece contacts the deformation amount adjusting means in a rolling contact state. As a result, even when the locking piece and the deformation amount adjusting means are in contact with each other, the resistance when the deformation amount adjusting means is displaced within the movable range can be suppressed as small as possible to achieve smooth displacement.

  According to the present invention, the displacement limiting means is provided, and the movable range of the deformation amount adjusting means for changing the deformation amount of the spring means for setting the relief pressure can be switched by switching between the allowable state and the limited state. it can. As a result, the maximum deformation amount of the spring means deformed by the deformation amount adjusting means is switched, and the maximum relief pressure is switched. Thus, it becomes possible to switch the maximum relief pressure by a simple operation of switching the displacement limiting means, and a plurality of maximum relief pressures can be set.

  Further, according to the present invention, it is possible to realize a switching operation of the displacement limiting means with a simple configuration and a simple operation of controlling the supply and stop of the pilot fluid.

  Further, according to the present invention, the deformation amount adjusting means is provided with the locking portion, and the displacement restricting means is provided with the locking piece driven by the pilot fluid, so that the switching operation is performed with the pilot fluid to switch the maximum relief pressure. It is possible to realize a relief valve device that can be used.

  Further, according to the present invention, the pilot fluid can be driven only in the protruding direction, and the configuration can be simplified.

  Further, according to the present invention, it is possible to suppress the resistance when the deformation amount adjusting means is displaced within the movable range as small as possible, and achieve a smooth displacement.

  FIG. 1 is a cross-sectional view showing a relief valve device 1 according to an embodiment of the present invention. FIG. 2 is a view showing a fluid pressure symbol representing the relief valve device 1. For example, mechanical equipment such as construction machinery and industrial machinery is provided with a fluid pressure circuit and is driven using fluid. The pressure of the fluid in the fluid pressure circuit varies depending on the operating state of the mechanical equipment. If the fluid pressure in the fluid pressure circuit becomes too high, the fluid pressure circuit will be damaged. Therefore, in order to prevent the fluid pressure from becoming too high, the relief valve device 1 is provided in the fluid pressure circuit. The fluid is not particularly limited, but may be a liquid such as hydraulic oil.

  In a state where the primary pressure P1 is equal to or lower than the relief pressure Pr that is set, the relief valve device 1 closes the valve passage 2 to prevent the flow of fluid, and when the primary pressure P1 exceeds the set relief pressure Pr, The valve passage 2 is opened to allow the fluid to flow down, thereby preventing the fluid pressure in the fluid pressure circuit from becoming too high. The relief valve device 1 includes a housing 3, a plunger 4 that is a valve body, a pressure setting spring member 5 that is a spring means, a deformation amount adjusting piston 6 that is a deformation amount adjusting means, and a displacement limiting means 7. Consists of. The plunger 4, the pressure setting spring member 5, the deformation amount adjusting piston 6 and the displacement limiting means 7 are housed in the housing 3.

  The housing 3 is generally formed in a hollow cylindrical shape by closely connecting a plurality of constituent members 13 to 16. In the housing 3, a primary port 11 is formed at one end 3 a in the axial direction, a secondary port 12 is formed at the outer peripheral portion near the one end in the axial direction, and each port 11 communicates with the valve passage 2. Is formed. A valve seat 19 is formed in the housing 3.

  The plunger 4 is generally formed in a cylindrical shape. The plunger 4 has a tapered truncated cone-shaped poppet valve portion 20 formed at one end portion 4a in the axial direction, and is located radially outward in the intermediate portion 4c between the both end portions 4a and 4b in the axial direction as compared with the remaining portion. A protruding flange portion 21 is formed. In the present embodiment, the flange portion 21 is formed adjacent to the poppet valve portion 20.

  The plunger 4 is disposed in the housing 3 in a state where the one end 4a side in the axial direction is located on the one end 3a side in the axial direction of the housing 3 and is supported so as to be displaceable along the axis. Sealing is achieved between the outer peripheral portion of the flange portion 21 and the inner peripheral portion of the housing 3, and the space in the housing 3 is partitioned by the flange portion 21, and is one end in the axial direction than the flange portion 21 in the space in the housing 3. The portion on the side of the portion 3 a becomes the valve passage 2.

  The plunger 4 is displaceable in an opening direction A1 in which the opening is increased and a closing direction A2 in which the opening is decreased over a closed position 22 that closes the valve passage 2 and a fully open position 23 that opens the valve passage at the maximum opening. . A closed position 22 indicated by a solid line in FIG. 1 is a position where the poppet valve portion 20 is seated on the valve seat 19 and displacement in the closing direction A2 is prevented. The open position 23 indicated by the phantom line in FIG. 1 is a position where the flange portion 21 abuts against the abutment portion 24 formed in the housing 3 and displacement in the open direction A1 is prevented. This is the position farthest from the valve seat 19. The opening direction A1 and the closing direction A2 (hereinafter sometimes collectively referred to as “opening / closing direction A”) are directions along the axis of the plunger 4.

  The pressure setting spring member 5 is realized by a compression coil spring, and is provided by being externally fitted to a portion on the other end side in the axial direction with respect to the flange portion 21 of the plunger 4. A spring seat 30 that is a spring receiving piece is provided in the housing 3. The spring seat 30 has an annular shape, and is externally fitted to a portion of the plunger 4 on the side of the other end 4 b in the axial direction than the flange portion 21, and is disposed on the side of the other end 4 a in the axial direction with respect to the pressure setting spring member 5. Provided. One end 5 a in the axial direction of the pressure setting spring member 5 is supported by the flange portion 21 of the plunger 4, and the other end 5 b in the axial direction of the pressure setting spring member 5 is supported by the spring seat 30. The pressure setting spring member 5 presses the plunger 4 in the closing direction A2 by an elastic recovery force (hereinafter sometimes referred to as “spring force”).

  The deformation adjustment piston 6 includes a piston portion 25 of an intermediate portion 6c between both axial end portions 6a and 6b, a cylindrical portion 26 on the axial end portion 6a side of the piston portion 25, and an axial direction other than the piston portion 25. And a shaft portion 27 on the end 6b side. The outer diameters of the cylindrical portion 26 and the shaft portion 27 are smaller than the outer diameter of the piston portion 25.

  The deformation adjustment piston 6 is arranged so that the axial one end 6 a side is on the axial one end 3 a side of the housing 3, and on the other axial end 3 b side of the housing 3 than the plunger 4 and the pressure setting spring member 5. The housing 3 is coaxially accommodated. A sleeve 28 which is a cylindrical member is fixedly provided in the housing 3. The deformation amount adjusting piston 6 has a shaft portion 27 inserted through the sleeve 28, and the other end in the axial direction of the deformation amount adjusting piston 6. A free end portion of the shaft portion 27 that is the portion 6 b opposite to the piston 25 (hereinafter, this free end portion may also be denoted by “6 b”) is provided so as to protrude from the sleeve 28. Further, the other end 4 b in the axial direction of the plunger 4 is inserted into the cylindrical portion 26 of the deformation amount adjusting piston 6.

  Sealing is achieved between the outer peripheral portion of the piston portion 25 and the inner peripheral portion of the housing 3, and sealing is achieved between the outer peripheral portion of the cylindrical portion 26 and the inner peripheral portion of the housing 3, and the outer peripheral portion of the shaft portion 27. A seal is achieved between the inner periphery of the sleeve 28 and the inner periphery of the sleeve 28, and a seal is achieved between the inner periphery of the cylindrical portion 26 and the outer periphery of the plunger 4. The deformation amount adjusting piston 6 can be displaced along the axis with respect to the housing 3 and the plunger 4.

  The deformation adjusting piston 6 has a free end portion on the opposite side to the piston 25 in the cylindrical portion 26 that is the axial end portion 6a (hereinafter, the free end portion may also be denoted by reference numeral “6a”) as a spring seat. 30 is provided so as to come into contact with the pressure setting spring member 5 from the opposite side. Therefore, the deformation adjustment piston 6 supports the other axial end 5 b of the pressure setting spring member 5 via the spring seat 30. Therefore, when the deformation amount adjusting piston 6 is displaced, the spring seat 30 is displaced, and the deformation amount of the pressure setting spring member 5 is changed.

  The deformation amount adjusting piston 6 has a deformation direction B1 in which the deformation amount is increased over a minimum position 31 where the deformation amount of the pressure setting spring member 5 is minimum and a maximum position 32 where the deformation amount of the pressure setting spring member 5 is maximum. And it can be displaced in the recovery direction B2 to reduce the deformation amount. A minimum position 31 indicated by a solid line in FIG. 1 is a position where displacement in the recovery direction B2 is prevented. A maximum position 32 indicated by an imaginary line in FIG. 1 is a position where displacement in the deformation direction B1 is prevented. The deformation direction B1 is the same as the closing direction A2, and the recovery direction B2 is the same as the opening direction A1. The deformation direction B1 and the recovery direction B2 (hereinafter sometimes collectively referred to as “deformation amount adjustment direction B”) are directions along the axis of the deformation amount adjustment piston 6.

  A first pressure chamber 36 defined by the plunger 4 and the deformation amount adjusting piston 6 is formed in the cylindrical portion 26 in a state where the plunger 4 and the deformation amount adjusting piston 6 are provided in the housing 3 as described above. A second pressure chamber 37 defined by the housing 3, the piston portion 25, the shaft portion 27, and the sleeve 28 is formed, and a third pressure chamber 37 defined by the housing 3, the piston portion 25, and the cylindrical portion 26 is formed. Is done. The second pressure chamber 37 faces the end surface portion of the piston portion 25 on the other axial end portion 6b side, and the third pressure chamber 38 faces the end surface portion of the piston portion 25 on the one axial end portion 6a side. .

  The plunger 4 is formed with an in-plunger passage 40 penetrating in the axial direction and having a throttle, and the first pressure chamber 36 is connected to the primary port 11 side portion of the valve passage 2 by the in-plunger passage 40. Further, the deformation adjusting piston 6 penetrates through the inside of the cylindrical portion 26 and the outside of the shaft portion 27, penetrates through the non-throttle passage 41 in the piston having no restriction, and the inside and outside of the cylindrical portion 26, and restricts the restriction. And the second pressure chamber 37 is connected by the non-throttle passage 41 in the piston, and the third pressure chamber 38 is connected by the throttling passage 42 in the piston.

  In the relief valve device 1, the pressure chambers 36 to 38 and the passages 40 to 42 are formed, and the plunger 4 generates a fluid pressure driving force based on the primary pressure P <b> 1 that is the pressure of the fluid in the primary port 11. The deformation amount adjusting piston 6 receives the fluid pressure driving force based on the primary pressure P1 in the deformation direction B1. Accordingly, when the primary pressure P1 increases, the plunger 4 is driven in the opening direction A1, and the plunger 4 is displaced in the opening direction A1 against the spring force of the pressure setting spring member 5. Is displaced in the deformation direction B1 against the spring force of the pressure setting spring member 5 as the driving force pressed in the deformation direction B1 increases. Conversely, when the primary pressure P1 decreases, the driving force pressed in the opening direction A1 decreases and the plunger 4 is displaced in the closing direction A2 by the spring force of the pressure setting spring member 5, and the deformation adjustment piston 6 is The driving force pressed in the deformation direction B1 is reduced and is displaced in the recovery direction B2 by the spring force of the pressure setting spring member 5.

  The displacement limiting means 7 is a means for limiting the displacement of the deformation amount adjusting piston 6 and switching the movable range, and is switched between a restricted state and an allowable state. In the present embodiment, the restricted state and the allowable state are switched by supplying and stopping the supply of pilot fluid.

  FIG. 3 is an enlarged cross-sectional view showing the main components of the displacement limiting means 7. 4-6 is sectional drawing for demonstrating operation | movement of the deformation amount adjustment piston 6 and the displacement limitation means 7. FIG. 4 shows a state in which the deformation amount adjustment piston 6 is at the minimum position 31, FIG. 5 shows a state in which the deformation amount adjustment piston 6 is in the maximum position 32, and FIG. 45 shows the state. As described above, the deformation amount adjusting piston 6 can be displaced within the range between the minimum position 31 and the maximum position 32, and this range is the entire movable range of the deformation amount adjusting piston 6.

  When the deformation adjustment piston 6 is at the minimum position 31, the spring seat 30 supported by the cylindrical portion 26 of the deformation adjustment piston 6 contacts and abuts a contact portion 47 formed on the housing 3. The spring seat 30 is prevented from being displaced in the same direction as the recovery direction B2. In the state in which the spring seat 30 is in contact with the contact portion 30, the spring force of the pressure setting spring member 5 is not applied to the piston, and the deformation adjustment piston 6 has a fluid in the deformation direction B1 based on the primary pressure P1. Only the pressure driving force is applied. Therefore, the displacement of the deformation adjustment piston 6 in the recovery direction B2 is prevented.

  When considering only the shape and dimensional configuration without considering the configuration relating to the driving force, the deformation amount adjusting piston 6 can be further displaced in the recovery direction B2 until the piston portion 25 abuts against the sleeve 28. . Therefore, if a force larger than the fluid pressure driving force is applied in the recovery direction B2, the piston portion 25 can be further displaced in the recovery direction B2 until it abuts against the sleeve 28. In the relief valve device 1, however, Since no driving force is applied, the position of the deformation adjustment piston 6 in a state where the spring seat 30 is in contact with the contact portion 47 becomes the minimum position 31.

  When the deformation amount adjusting piston 6 is at the maximum position 32, the piston portion 25 comes into contact with the contact portion 34 formed in the housing 3, and displacement in the deformation direction B1 is prevented. The limit position 45 is a position set between the minimum position 31 and the maximum position 32.

  The allowable state in the displacement limiting means 7 is a state in which the displacement of the deformation amount adjusting piston 6 is fully allowed. In this permissible state, the deformation amount adjusting piston 6 can be displaced over the minimum position 31 and the maximum position 32, and the movable range of the deformation amount adjusting piston 6 is the entire movable range. The restricted state in the displacement restricting means 7 is a state in which the displacement of the deformation amount adjusting piston 6 is restricted. When in this limit state, the deformation amount adjusting piston 6 is prevented from being displaced beyond the limit position 45 to the maximum position 32 side, and the movable range of the piston is a range extending between the minimum position 31 and the limit position (hereinafter, “ It is sometimes referred to as a “limited movement range”.

  A rod 17, which is a substantially cylindrical member, is mounted on the other axial end 3 b of the housing 3 in a state where the rod 17 is coaxially inserted and the axial one end 17 a is partially inserted. The other axial end 17 b of the rod 17 protrudes from the housing 3. The rod 17 is formed with a cylindrical fitting recess 48 at one end 17a in the axial direction. The free end portion 6 b of the shaft portion 27 of the deformation amount adjusting piston 6 is inserted into the fitting recess 48 of the rod 17.

  A locking recess 50 that is recessed inward in the radial direction is formed on the outer peripheral portion of the free end portion 6 b of the shaft portion 27. The engagement recess 50 may be configured so that a later-described engagement piece 55 can be fitted, and may be formed only at one place in the circumferential direction, or may be formed at a plurality of places in the circumferential direction. Further, it may be formed over the entire circumference. In the present embodiment, the locking recess 50 is formed in a groove shape extending all around the circumferential direction.

  By forming the locking recess 50, the free end portion 6 b of the shaft portion 27 protrudes in a direction intersecting with the deformation amount adjusting direction B at a portion closer to the recovery direction B 1 than the locking recess 50. A locking portion 51 is formed. The locking portion 51 protrudes outward in the radial direction and extends over the entire circumference.

  The displacement limiting means 7 includes a locking piece 55, a pilot piston 56, and a stable spring member 57. Although the number of the locking pieces 55 is not limited, in the present embodiment, a plurality of, specifically four, locking pieces 55 are provided.

  At one end 17a in the axial direction of the rod 17, a through-hole 58 that penetrates inward and outward along the radial direction is formed at a position facing the locking recess 50 of the shaft portion 27 inserted into the fitting recess 48. Yes. In the present embodiment, the same number, that is, four through holes 58 are formed according to the number of the locking pieces 55. Each through-hole 58 is formed at intervals of, for example, 90 degrees in the circumferential direction.

  Each locking piece 55 is a rolling element, and is specifically realized by a sphere having a spherical shape, and more specifically, for example, by a steel ball. Each locking piece 55 is fitted into each through hole 58 one by one, and is provided so as to be displaceable in the radial direction of the deformation amount adjusting piston 6 along the axis of each through hole 58.

  Each locking piece 55 protrudes to the movement path 60 of the locking part 51 in accordance with the displacement of the deformation amount adjusting piston 6, and is retracted from the protruding position 61, that is, the movement path. Over the retracted position 62 retracted from 60, it can be displaced in a projecting direction C1 toward the projecting position 61 and a retracting direction C2 toward the retracted position 62. A protruding position 61 indicated by a solid line in FIG. 3 is a position where displacement in the protruding direction C1 is prevented. The retracted position 62 indicated by a virtual line in FIG. 3 is a position where displacement in the retracting direction C2 is prevented. The protruding direction C1 is a direction toward the inner side in the radial direction, and the retracting direction C2 is a direction toward the outer side in the radial direction. The protruding direction C1 and the retracting direction C2 (hereinafter sometimes collectively referred to as “state switching direction C”) are radial directions in the shaft portion 27 of the deformation adjustment piston 6, and are in the axis of each through hole 58. It is the direction along.

  The pilot piston 56 is a cylindrical member. A portion of the rod 17 near the one end 17a in the axial direction is spaced from the inner peripheral surface of the housing 3, and a cylindrical space is provided on the radially outer side of the portion near the one end 17a in the axial direction of the rod 17. Is formed. The pilot piston 56 is provided so as to be able to be displaced along the axis while being fitted coaxially to a portion of the rod 17 near the one end 17a in the axial direction so as to be fitted into the space.

  The pilot piston 56 is a member for operating each operation piece 55 at one end 56a in the axial direction by its displacement. The pilot piston 56 prevents the displacement of each locking piece 55 in the retracting direction C2 and the blocking position 65 that prevents the locking piece 55 from being displaced in the retracting direction C2 with each locking piece 55 protruding to the protruding position 61. Over the release position 62 to be released, it is displaceable in a blocking direction D1 toward the blocking position 65 and a releasing direction D2 toward the release position 66.

  A blocking position 65 indicated by a solid line in FIG. 3 is a position where displacement in the blocking direction D1 is blocked. A release position 66 indicated by a virtual line in FIG. 3 is a position where displacement in the release direction D2 is prevented. The blocking direction D1 is the same as the closing direction A2, and the releasing direction D2 is the same as the opening direction A1. The blocking direction D <b> 1 and the release direction D <b> 2 (hereinafter, sometimes collectively referred to as “state operation direction D”) are directions along the axis of the pilot piston 56.

  A seal is achieved between the inner periphery of the pilot piston 56 and the outer periphery of the rod 17, and a seal is achieved between the outer periphery of the pilot piston 56 and the inner periphery of the housing 3. As a result, a fourth pressure chamber 68 defined by the pilot piston 56, the rod 17, and the housing 3 is formed. The fourth pressure chamber 68 faces the other end 56b of the pilot piston 56 in the axial direction.

  The rod 17 is formed with a pilot port 70 at one end 3a in the axial direction, and further, an inner rod passage 71 is formed through the inside. The fourth pressure chamber 68 is connected to the pilot port 70 by the in-rod passage 71. Thus, when the pilot fluid is supplied to the pilot port 70 and the pilot pressure Pp is guided, the pilot piston 56 is pressed in the blocking direction D1 by the fluid pressure driving force based on the pilot pressure Pp, and the supply of the pilot fluid is stopped. Then, the pressing in the blocking direction D1 by the fluid pressure driving force based on the pilot pressure Pp against the pilot piston 56 is released.

  The stable spring member 57 is realized by a compression coil spring, and is provided in the fourth pressure chamber 68 by being externally fitted to the rod 17. One axial end portion 57 a of the stable spring member 57 is supported by the other axial end portion 56 b of the pilot piston 56, and the other axial end portion 57 b of the stable spring member 57 is supported by the spring support portion 73 of the housing 3. Yes. The stable spring member 57 presses the pilot piston 56 in the blocking direction D1 by an elastic recovery force (hereinafter sometimes referred to as “spring force”).

  The end portion 56a in the axial direction of the pilot piston 56 has a conical shape that expands outward in the radial direction toward the inner peripheral portion from the other end portion 56b in the axial direction toward the one end portion 56a in the axial direction (blocking direction D1). A trapezoidal operation surface 75 is formed. Each locking piece 55 is provided in contact with the operation surface 75. Each locking piece 55 and the pilot piston 56 are guided to each other with the operation surface 75 serving as a guide surface. When the pilot piston 56 is displaced in the blocking direction D1, each locking piece 55 is pressed by the pilot piston 56 and displaced in the protruding direction C1. Conversely, when each locking piece 55 is displaced in the retracting direction C2, the pilot piston 56 is pressed by each locking piece 55 and is displaced in the releasing direction D2. The stable spring member 57 maintains the contact state between the pilot piston 56 and each locking piece 55 and stably achieves the interlocking operation as described above.

  An outer peripheral surface (hereinafter also referred to as “locking portion outer peripheral surface”) 76 of the locking portion 51 of the shaft portion 27 is an outer peripheral surface facing the locking recess 50 of the shaft portion 27 (hereinafter referred to as “recess outer peripheral surface”). Projecting radially outward from 77 and faces the locking recess 50 of the locking portion 51, which is a step surface between the locking portion outer peripheral surface 76 and the recess outer peripheral surface 77. The surface becomes the locking surface 78. When the locking surface 78 abuts on the locking pieces 55, the locking portion 51 can be locked by the locking pieces 55.

  The locking surface 78 is formed in a truncated cone shape whose diameter decreases inward in the radial direction as it goes from the other axial end 6b to the axial one end 6a (deformation direction B1). As a result, the contact position with respect to the deformation adjustment piston 6 can be moved over the outer peripheral surface 76 of the locking portion and the outer peripheral surface 77 of the recess while each locking piece 55 is pressed in the blocking direction C1. ing. As described above, in the present embodiment, the deformation amount adjusting piston 6 is deformed while being locked to at least one of the locking portion 51 and the locking piece 55, specifically, the locking portion 51. The locking surface 78 functions as a guide surface for guiding the locking piece 55 to be displaced in the retracting direction C2 when displaced in the direction B1.

  In a state where the pilot fluid is not supplied, the pilot piston 56 is pressed only by the spring force of the stable spring member 57 in the blocking direction D1. When the deformation amount adjusting piston 6 is between the minimum position 31 and the limit position 45, each locking piece 55 is in the protruding position 61 that fits into the locking recess 50, and the pilot piston 56 is in the blocking position 65. Yes, it is stable without being displaced by the spring force of the stable spring 56. In this state, the deformation amount adjusting piston 6 can be displaced in the deformation amount adjusting direction B between the minimum position 31 and the limit position 45.

  When the deformation amount adjusting piston 6 is at the limit position 45, the locking surface 73 of the locking portion 51 is in contact with each locking piece 55. If the deformation amount adjusting piston 6 tries to displace to the maximum position 32 side beyond the limit position 45 in a state where the pilot fluid is not supplied, the deformation amount adjusting piston 6 is stabilized by the driving force based on the primary pressure P1. The retraction direction C <b> 2 so as to overcome the pressing force due to the spring force of the member 57, guide each locking piece 55 to the locking surface 78, and run on the locking portion outer peripheral surface 76 apart from the recess outer peripheral surface 77. It is possible to displace to the maximum position 32 while displacing to the maximum. At this time, the pilot piston 56 is interlocked and displaced in the release direction D2.

  In this state where the pilot fluid is not supplied, each locking piece 55 is pressed in the protruding direction C1 by the driving force based on the spring force of the stable spring member 57. It is smaller than the driving force given from the adjustment piston 6 based on the fluid pressure driving force based on the primary pressure P1. Each locking piece 55 is displaced in the state switching direction C while being guided by the locking surface 78 as the deformation amount adjusting piston 6 is displaced. Therefore, the state in which the pilot fluid is not supplied is an allowable state, and the locking portions 51 cannot be locked by the locking pieces 55, and the displacement of the deformation adjustment piston 6 is fully allowed over the entire movable range. The

  In a state where the pilot fluid is supplied, the pilot piston 56 is pressed in the blocking direction D1 with a fluid pressure driving force based on the spring force of the stable spring member 57 and the pilot pressure Pp. When the deformation amount adjusting piston 6 is between the minimum position 31 and the limit position 45, each locking piece 55 is in the protruding position 61 that fits into the locking recess 50, and the pilot piston 56 is in the blocking position 65. The displacement is prevented by the spring force of the stable spring 56 and the pilot pressure Pp. In this state, the deformation amount adjusting piston 6 can be displaced in the deformation amount adjusting direction B between the minimum position 31 and the limit position 45.

  Even if the deformation amount adjusting piston 6 tries to displace to the maximum position 32 side beyond the limit position 45 in the state where the pilot fluid is supplied, the deformation amount adjusting piston 6 is stable spring with the driving force based on the primary pressure P1. The pressing force by the fluid pressure driving force based on the spring force of the member 57 and the pilot pressure Pp cannot be overcome, and each locking piece 55 cannot be displaced in the retracting direction C2. Accordingly, the locking portion 51 is locked by the locking pieces 55, and the deformation amount adjusting piston 6 is prevented from being displaced beyond the limit position 45 to the maximum position 32 side.

  Thus, in the state where the pilot fluid is supplied, each locking piece 55 is pressed in the protruding direction C1 by the fluid pressure driving force based on the spring force of the stable spring member 57 and the pilot pressure Pp. This driving force is larger than the driving force applied from the deformation amount adjusting piston 6 based on the fluid pressure driving force based on the primary pressure P1. Each locking piece 55 does not displace in the state switching direction C, and locks the locking portion 51 when it comes into contact with the locking surface 78 with respect to the displacement of the deformation adjustment piston 6. Accordingly, the state in which the pilot fluid is supplied is in a limited state, and the locking portion 51 can be locked by each locking piece 55, and the displacement of the deformation amount adjusting piston 6 is the minimum position 31 and the limiting position 45. Is limited to the movable range between.

  As described above, in the displacement limiting means 7, each locking piece 55 is in contact with the outer peripheral surface 77 of the recess in the state of being in the protruding position 61, and is prevented from being displaced in the protruding direction C 1. At 65, the displacement in the blocking direction D1 is blocked by contacting each locking piece 55. Further, in the displacement limiting means 7, the position when the deformation amount adjusting piston 6 is at the maximum position 32 is the retracted position 62 of each locking piece 55 and the release position 66 of the pilot piston 58. When each locking piece 55 is in the retracted position 62, the locking piece 55 may be in a position in contact with the locking portion outer peripheral surface 76, or may be in a position in contact with the locking surface 78. When the deformation amount adjusting piston 6 is at the maximum position 32, each locking piece 55 is retracted from the movement path 60 and is not further displaced in the retracting direction C2 by the deformation amount adjusting piston 6, and the pilot piston 56 Is not displaced in the release direction D2. In this case, each locking piece 55 is at the retracted position 62 and is prevented from being displaced in the retracted direction C2, and the pilot piston 6 is at the release position 66 and is prevented from being displaced in the released direction D2.

  The relief valve device 1 configured as described above is attached to a body 81 in the housing 3 where a part of the flow path 80 in the fluid pressure circuit is formed. As a result, the relief valve device 1 is arranged in the middle of the flow path 80 in a state where the primary port 11 is connected to the primary side portion of the flow path 80 and the secondary port 12 is connected to the secondary side portion of the flow path 80. Intervened.

  FIG. 7 is a graph showing the relief pressure Pr in the relief valve device 1. In FIG. 7, the horizontal axis is time t, and the vertical axis is the relief pressure Pr. According to the relief valve device 1 of the present embodiment, the plunger 4 is pressed in the opening direction A1 by the fluid pressure driving force based on the primary pressure P1, and in the closing direction A2 by the elastic recovery force of the pressure setting spring member 5. It is pressed. Accordingly, in the relief valve device 1, the primary pressure P1 when the fluid pressure driving force and the elastic recovery force received by the plunger 4 are equal is set as the relief pressure Pr, and the primary pressure P1 exceeds the relief pressure Pr. When the pressure is reached, the plunger 4 is displaced in the opening direction A1, and the valve passage 2 can be opened. The pressure setting spring member 5 for setting the relief pressure Pr is supported by the deformation amount adjusting piston 6, the deformation amount is changed by the displacement of the deformation amount adjusting piston 6, and the generated elastic recovery force is generated. The deformation amount adjusting piston 6 receives a fluid pressure driving force based on the primary pressure P1 in the deformation direction, and increases the deformation amount of the pressure setting spring member 5 as the primary pressure P1 increases. Accordingly, the relief pressure Pr is set to gradually increase as the primary pressure P1 increases.

  As shown in FIG. 7, the relief pressure Pr gradually increases with time, and finally reaches the maximum relief pressure Ps (PsL, PsH). The maximum relief pressure Ps is a relief pressure Pr set in a state where the deformation amount adjusting piston 6 is not displaced in the deformation direction B1. As described above, the relief valve device 1 has a pressure increasing buffer function in which the relief pressure Pr is gradually increased.

  The relief valve device 1 is further provided with a displacement limiting means 7 for limiting the displacement of the deformation amount adjusting piston 6 that contributes to the setting of the relief pressure Pr. The displacement limiting means 7 is provided so that it can be switched between a limiting state in which the displacement of the deformation amount adjusting piston 6 is limited and an allowable state in which the displacement of the deformation amount adjusting piston 6 is fully allowed. When the displacement limiting means 7 is in the allowable state, the deformation amount adjusting piston 6 can be displaced between the minimum position 31 and the maximum position 32 without being limited, and can be displaced to the maximum position 32. it can. In this permissible state, the movable range of the deformation amount adjusting piston 6 is a range extending from the minimum position 31 to the maximum position 32. When the deformation amount adjusting piston 6 is disposed at the maximum position 32, the pressure setting spring member 5 Becomes the most deformed state, and the relief pressure Pr set in this state becomes the maximum relief pressure Ps. The maximum relief pressure Ps in the allowable state is the high maximum relief pressure PsH.

  On the other hand, when the displacement limiting means 7 is in the limited state, the deformation amount adjusting piston 6 is displaced to the maximum position 32 side beyond the limit position 45 set between the minimum position 31 and the maximum position 32. To prevent. In this restricted state, the movable range of the deformation amount adjusting piston 6 is a range extending between the minimum position 31 and the restricting position 45, and when the deformation amount adjusting piston 6 is disposed at the restricting position 45, the pressure setting spring member 5. Becomes the most deformed state, and the relief pressure Pr set in this state becomes the maximum relief pressure Ps. In the restricted state, the deformation amount in the state where the pressure setting spring member 5 is most deformed is smaller than the deformation amount in the most deformed state in the allowable state, and the maximum relief pressure Ps in the restricted state is higher than the high maximum relief pressure PsH. The low maximum relief pressure PsL is also low.

  Thus, the maximum relief pressure Ps differs between when the displacement limiting means 7 is in the allowable state and when it is in the limited state. Therefore, the maximum relief pressure Ps can be switched by a simple operation of switching the displacement limiting means 7, and a plurality of maximum relief pressures Ps can be set. In the present embodiment, it can be set in two stages of a high maximum relief pressure PsH and a low maximum relief pressure PsL.

  Further, as described above, the displacement limiting means 7 can be switched between a limited state and an allowable state by controlling the supply and stoppage of the pilot fluid to the pilot port 70. As a result, the switching operation of the displacement limiting means 7 can be realized with a simple configuration and with a simple operation of controlling the supply and stoppage of the pilot fluid. As the pilot fluid, a fluid supplied from a working fluid supply source in the fluid pressure circuit may be used, or a pilot fluid supply source may be separately provided and fluid supplied from this supply source. May be used. The supply and stop of the pilot fluid may be operated by a simple switching valve device interposed between the supply source and the supply source.

  Further, the displacement restricting means 7 is in a state in which the locking piece 55 cannot lock the locking portion 51 in the allowable state. In this state, the locking portion 51 is not locked by the locking piece 55, and the deformation amount adjusting piston 6 can be displaced over the minimum position 31 and the maximum position 32. Further, the displacement limiting means 7 is in a state where the locking piece 55 can lock the locking portion 51 in the limited state. In this state, the locking portion 51 is locked by the locking piece 55, and the deformation amount adjusting piston 6 is prevented from being displaced beyond the limit position 45 to the maximum position 32 side. In this way, the deformation adjusting P 4 ton 6 is provided with a locking portion, and the displacement limiting means 7 is provided with the locking piece 55 driven by the pilot fluid, so that the switching operation is performed with the pilot fluid, and the maximum relief pressure Ps. Can be realized.

  Further, when the deformation amount adjusting piston 6 is displaced in the deformation direction B1, the engaging piece 55 is guided so as to be displaced in the retracting direction B2 by the engaging surface 78 serving as a guide surface. Accordingly, in the restricted state, the engaging piece 55 is pressed in the protruding direction C1 by the driving force based on the pilot pressure Pp to prevent the engaging piece 55 from being displaced in the retracting direction C2, and when the restricted piece is switched from the restricted state to the allowed state. Even if it is not displaced in the retracting direction C2, it is displaced in the retracting direction C2 by the deformation amount adjusting piston 6 only by stopping the supply of the pilot fluid. Therefore, the pilot fluid can be driven only in the protruding direction C1, and the configuration can be simplified.

  Further, by using the locking piece 55 that is a rolling element, the locking piece 55 comes into contact with the deformation amount adjusting piston in a rolling contact state. Accordingly, even when the locking piece 55 and the deformation amount adjusting piston 6 are in contact with each other, the resistance when the deformation amount adjusting piston 6 is displaced within the movable range can be suppressed as small as possible, and smooth displacement can be achieved. .

  FIG. 8 is a fluid pressure circuit diagram showing an example of a fluid pressure circuit in which the relief valve device 1 is used. In FIG. 8, the relief valve device 1 is indicated by a simplified symbol. For example, as described above, a fluid pressure circuit that can be used to turn a swivel base in a construction machine or an industrial machine includes a fluid pressure motor 85, a pump 86 and a tank 87 constituting a supply source, and a switching valve 88. Have. In this fluid pressure circuit, by operating the switching valve 88, the working fluid is supplied to the fluid pressure motor 85 by one of the two input / output channels 90 and 91, and the working fluid is returned to the tank 87 by the other. The fluid pressure motor 85 is rotated. In such a fluid pressure circuit, immediately after the supply of the working fluid to the fluid pressure motor 85 is started and immediately after the supply of the working fluid to the fluid pressure motor 85 is stopped, each input is made by the inertia of the fluid pressure motor 85. The pressure of the working fluid in the output flow paths 90 and 91 is increased. In order to prevent the pressure from rising, one bypass flow path (same reference numeral in FIG. 1) 80 is provided between the input / output flow paths 90 and 91, and the bypass flow path 80 has a secondary side. The two relief valve devices 1 are provided so as to face each other, and the bypass flow path 80 is connected to the tank 87 between the relief valve devices 1. With such a configuration, the pressure of the working fluid in the fluid pressure circuit can be prevented from becoming too high.

  FIG. 9 is a fluid pressure circuit diagram showing another example of a fluid pressure circuit in which the relief valve device 1 is used. In FIG. 9, the relief valve device 1 is indicated by a simplified symbol. Only a circuit configuration different from the circuit configuration shown in FIG. 8 will be described. In the configuration of FIG. 8, two relief valve devices 1 are provided so as to face one bypass flow path 80, but in the configuration of FIG. 9, two bypass passages 80 are provided between the input / output flow paths 90 and 91. The relief valve device 1 is provided in each bypass channel 80 in different directions. Even with such a configuration, the pressure of the working fluid in the fluid pressure circuit can be prevented from becoming too high.

  FIG. 10 is an enlarged cross-sectional view showing a part of a relief valve device 1A according to another embodiment of the present invention. The relief valve device 1A of the present embodiment is similar to the relief valve device 1 of the embodiment of FIGS. 1 to 9, and corresponding portions are denoted by the same reference numerals, and only different configurations will be described. In the present embodiment, the deformation amount adjusting piston 6 is provided with two locking portions 51 in the axial direction, and the rod 17 is provided with two locking pieces 55 in the two axial directions. The locking piece 55 provided at one location is provided with a locking portion 51 formed at one location when the deformation adjustment piston 6 is in the first limit position 45a (the position indicated by the solid line in FIG. 10). The locking piece 55 that is locked and provided at the other place is when the deformation amount adjusting piston 6 is in the second limit position 45b (position indicated by the imaginary line in FIG. 10) different from the first limit position 45a. In addition, the locking portion 51 formed at the other location can be locked. The first and second restriction positions 45a and 45b are both restriction positions 45, respectively.

  Each locking piece 55 is configured to be pressed in the protruding direction C1 by a fluid pressure driving force based on the pilot pressure Pp via a pilot operating member 100 provided on the rod 17 so as to be closely slidable. Further, the locking piece 55 provided at one location and the locking piece 55 provided at the other location can be individually and selectively driven with a fluid pressure driving force based on the pilot pressure Pp. When the pilot pressure Pp is not guided, the locking piece 55 is pressed by the displacement adjustment piston 6 and displaced in the retreat direction C2. With such a configuration, a plurality of restriction positions can be provided. As a result, the maximum relief pressure Ps can be set in three or more stages. In the configuration of FIG. 10, the maximum relief pressure Ps can be set in three stages by two restriction positions.

  As shown in FIGS. 1 to 9, the restriction position may be one, but may be plural as shown in FIG. 10. When there is one limit position, the maximum relief pressure Ps can be set in two stages. When there are a plurality of restriction positions, the maximum relief pressure Ps can be set in three or more stages according to the number of restriction positions.

  The above-described embodiment is merely an example of the present invention, and the configuration can be changed within the scope of the present invention. For example, the configuration for limiting the displacement of the deformation amount adjusting piston is not limited to the above-described configuration, and may be another configuration. Further, the fluid is not limited to hydraulic oil, and may be implemented as a relief valve device provided other than construction machinery or industrial machinery.

It is sectional drawing which shows the relief valve apparatus 1 of one Embodiment of this invention. It is a figure which shows the fluid pressure symbol showing the relief valve apparatus. FIG. 4 is an enlarged cross-sectional view showing main components of the displacement limiting means 7. FIG. 6 is a cross-sectional view for explaining operations of the deformation amount adjusting piston 6 and the displacement limiting means 7. FIG. 6 is a cross-sectional view for explaining operations of the deformation amount adjusting piston 6 and the displacement limiting means 7. FIG. 6 is a cross-sectional view for explaining operations of the deformation amount adjusting piston 6 and the displacement limiting means 7. 3 is a graph showing a relief pressure Pr in the relief valve device 1; It is a fluid pressure circuit diagram showing an example of a fluid pressure circuit in which the relief valve device 1 is used. It is a fluid pressure circuit diagram which shows the other example of the fluid pressure circuit where the relief valve apparatus 1 is used. It is sectional drawing which expands and shows a part of relief valve apparatus 1A of other form of implementation of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Relief valve apparatus 2 Valve passage 3 Housing 4 Plunger 5 Pressure setting spring member 6 Deformation amount adjustment piston 7 Displacement restricting means 11 Primary port 12 Secondary port 51 Locking part 55 Locking piece 56 Pilot piston 57 Stabilizing spring member 78 Locking surface

Claims (5)

A housing in which a valve passage is formed;
Fluid pressure drive based on the primary pressure, which is displaceable in the opening direction that increases the opening and the closing direction that decreases the opening over the closed position that closes the valve passage and the fully open position that opens the valve passage at the maximum opening A valve body that receives force in the opening direction;
Spring means for pressing the valve body in the closing direction by elastic recovery force;
The spring means is supported and displaced in the deformation direction in which the amount of deformation is increased and the recovery direction in which the amount of deformation is reduced over the minimum position where the amount of deformation of the spring means is minimum and the maximum position where the amount of deformation of the spring means is maximum. A deformation amount adjusting means that is provided in a deformable direction and receives a fluid pressure driving force based on the primary pressure in the deformation direction;
A switching operation is provided between a permissible state in which the displacement of the deformation amount adjusting means is completely allowed and a restricted state in which the displacement of the deformation amount adjusting means is restricted. In the restricted state, the deformation amount adjusting means has a minimum position and a maximum position. And a displacement limiting means for preventing displacement to a maximum position side beyond a limit position set between the relief valve device and the relief valve device.   2. The relief valve device according to claim 1, wherein the displacement limiting means can be switched between a limited state and an allowable state by supplying and stopping the supply of pilot fluid. The deformation amount adjusting means has a locking portion protruding in a direction intersecting the deformation direction and the recovery direction,
The displacement limiting means can be displaced in the protruding direction toward the protruding position and in the retracting direction toward the retracted position over the protruding position for locking the locking portion accompanying the displacement of the deformation amount adjusting means and the retracted position retracted from the protruding position. 3. A relief valve according to claim 2, further comprising a locking piece that is driven to a state where the locking portion can be locked and a state where the locking portion cannot be locked by supplying and stopping the supply of pilot fluid. apparatus.   At least one of the locking portion and the locking piece is guided so that the locking piece is displaced in the retracting direction when the deformation amount adjusting means is displaced in the deformation direction while being locked together. 4. A relief valve device according to claim 3, wherein a guiding surface is formed.   The relief valve device according to claim 3 or 4, wherein the locking piece is a rolling element.

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