JP6006657B2 - Hydraulic damper - Google Patents

Description

  The present invention relates to a hydraulic damper, and more particularly, to an improvement of a hydraulic damper suitable for use in a seismic isolation device that suppresses vibration of a structure or a large machine.

  The seismic isolation device is equipped with a support device such as a ball isolator or rubber interposed between the ground and the structure, and supports the structure so that it can be displaced relative to the ground, and transmits seismic motion to the structure. It is designed to be insulated. Moreover, this seismic isolation device includes a hydraulic damper interposed between the ground and the structure in addition to the support device as described above, and the hydraulic damper generates vibration of the structure. Damping with a damping force suppresses the vibration of the structure.

  The seismic isolation device has a smaller damping force of the hydraulic damper in the event of an earthquake, and is less likely to transmit the ground vibration to the structure and can ensure high vibration insulation. If the vibration damping force is small, it may not be possible to suppress the movement of the structure when large vibrations are input, and the structure may fall off from the seismic isolation device. Especially, a high-rise building built in a narrow area For example, when the amplitude increases, it may interfere with the adjacent building, and a hydraulic damper capable of exhibiting a high damping force against a large amplitude vibration is desired.

  Therefore, in a hydraulic damper used in this type of seismic isolation device, a cylinder, a piston that is slidably inserted into the cylinder and divides the cylinder into an extension side chamber and a compression side chamber, a tank, and an extension Two passages leading from the side chamber to the tank, a damping valve provided in each of the passages, a check valve allowing only the flow of liquid from the tank to the pressure side chamber, and a piston provided from the pressure side chamber to the extension side chamber And a check valve that allows only the flow of liquid to the side.When the external force increases and the stroke of the hydraulic damper increases, the passage to one of the damping valves is blocked, and the damping force against large vibrations The gradient can be increased (for example, see Patent Document 1).

  The hydraulic damper has two damping valves effective for small-amplitude vibrations, exhibits a damping force by lowering the damping force gradient, and is provided in one passage for large-amplitude vibrations. By removing the pin linked to the piston rod from the ring that was holding the shut-off valve, this shut-off valve blocks the passage and increases the damping force gradient to exert the damping force. Yes. Therefore, this hydraulic damper can satisfy the demand of a damper suitable for a seismic isolation device.

JP 2010-255562 A

  By the way, the hydraulic damper is a uniflow damper in which the liquid discharged from the extension side chamber returns to the extension side chamber through the tank and the pressure side chamber and is a uniflow damper. The liquid is discharged from the cylinder into the tank.

  Therefore, when the hydraulic damper is extended, it is necessary to suck liquid from the tank in the pressure side chamber, and if the extension speed is high, a large amount of liquid must be supplied to the pressure side chamber. There is a limit to increasing the flow rate, and the flow rate cannot catch up, and the suction side tends to be insufficient. Thus, when insufficient suction of liquid occurs in the cylinder, the hydraulic damper cannot output the damping force as set, and it becomes difficult to effectively dampen the structure.

  Therefore, the present invention was devised to improve the above-described problems, and the object of the present invention is to provide a stable damping force while realizing a damping characteristic suitable for a seismic isolation device. It is to provide a possible hydraulic damper.

  In order to achieve the above object, the hydraulic damper in the problem solving means of the present invention includes a cylinder, a piston that is slidably inserted into the cylinder, and a movably inserted into the cylinder. A piston rod coupled to the piston; a rod side chamber and a piston side chamber partitioned by the piston in the cylinder; a tank; and a flow of liquid from the rod side chamber to the piston side chamber while allowing the flow of liquid. A main extension side damping means for imparting resistance to the piston, a first main pressure side damping means for permitting the flow of liquid from the piston side chamber to the rod side chamber and for imparting resistance to the liquid flow, and from the piston side chamber to the tank. Second main pressure side damping means for allowing the flow of the liquid and giving resistance to the flow of the liquid, and from the tank to the piston side chamber In a hydraulic damper having a suction passage that allows a flow of liquid, an extension bypass path that bypasses the main extension side damping means and communicates the rod side chamber and the piston side chamber, and the first main pressure side attenuation A pressure side bypass passage that bypasses the means and communicates the rod side chamber and the piston side chamber, a discharge passage that branches from the pressure side bypass passage and communicates with the tank, and is provided in the middle of the extension side bypass passage. A secondary extension side damping means that allows the flow of liquid from the rod side chamber to the piston side chamber and provides resistance to the flow of the liquid, and an extension provided in the middle of the extension side bypass path to open and close the extension side bypass path A side logic valve and provided in the middle of the pressure side bypass passage and downstream from the branch point of the discharge passage allow the liquid to flow from the piston side chamber to the rod side chamber. Both of the first sub-pressure side damping means for providing resistance to the flow of the liquid and a second auxiliary pressure means provided in the middle of the discharge passage to allow the flow of liquid from the piston side chamber to the tank and to provide resistance to the liquid flow. A secondary pressure-side damping means, a pressure-side logic valve that is provided in the middle of the pressure-side bypass path and upstream from the branch point of the discharge passage, opens and closes the pressure-side bypass path, the extension-side logic valve, and the pressure-side logic valve And a control valve that controls opening and closing of the valve, and the control valve closes the extension side logic valve and the pressure side logic valve when the piston rod strokes a predetermined amount or more from a neutral position.

  When the stroke amount from the neutral position of the piston rod is less than the predetermined amount, the hydraulic damper according to the present invention can reduce the damping force gradient (the gradient of the characteristic in the damping force characteristic with respect to the piston speed). When the stroke amount from the neutral position becomes a predetermined amount or more, the damping force gradient can be increased.

  In the hydraulic damper according to the present invention, liquid is supplied from the rod side chamber to be expanded to the piston side chamber to be expanded during the extension operation, so that the amount of liquid sucked into the piston side chamber from the tank is reduced by the piston rod that retreats from the cylinder. Since the amount is only commensurate with the volume, there is no shortage of liquid in the cylinder, and the damping force is output as set.

  Therefore, according to the hydraulic damper of the present invention, a stable damping force can be exhibited while realizing a damping characteristic suitable for a seismic isolation device.

It is a hydraulic-pressure circuit diagram of the hydraulic damper in one embodiment. It is a figure which shows the damping characteristic at the time of the expansion | extension operation | movement of the hydraulic damper in one Embodiment.

  The present invention will be described below based on the illustrated embodiment. As shown in FIG. 1, a hydraulic damper D according to an embodiment includes a cylinder 1, a piston 2 that is slidably inserted into the cylinder 1, and a cylinder 1 that is slidably inserted into one end. The piston rod 3 connected to the piston 2, the rod side chamber R1, the piston side chamber R2 partitioned by the piston 2 in the cylinder 1, the tank 4, and the liquid flow from the rod side chamber R1 to the piston side chamber R2 are allowed. A main extension side damping means 5 for imparting resistance to the flow of the liquid, a first main pressure side damping means 6 for permitting the flow of liquid from the piston side chamber R2 to the rod side chamber R1, and for imparting resistance to the liquid flow, and a piston A second main pressure-side damping means 7 that allows the flow of liquid from the side chamber R2 to the tank 4 and provides resistance to the flow of the liquid; and the liquid from the tank 4 to the piston-side chamber R2. A suction passage 8 that allows flow, an extension side bypass passage 9 that bypasses the main extension side damping means 5 and communicates with the rod side chamber R1 and the piston side chamber R2, and a rod side chamber that bypasses the first main pressure side attenuation means 6 A pressure side bypass passage 10 that connects R1 and the piston side chamber R2, a discharge passage 11 that branches from the pressure side bypass passage 10 and communicates with the tank 4, and a rod side chamber R1 that extends from the rod side chamber R1 to the piston side chamber. The secondary extension side damping means 12 that allows the flow of liquid to R2 and provides resistance to the flow of the liquid, and the extension side logic provided in the middle of the extension side bypass path 9 to open and close the extension side bypass path 9 The valve 13 is provided in the middle of the pressure side bypass passage 10 and downstream from the branch point of the discharge passage 11 to allow the flow of liquid from the piston side chamber R2 to the rod side chamber R1 and the liquid. A first sub-pressure side damping means 14 that provides resistance to the flow, and a second sub-pressure side that is provided in the middle of the discharge passage 11 and allows the flow of liquid from the piston-side chamber R2 to the tank 4 and provides resistance to the flow of the liquid. A damping means 15, a pressure side logic valve 16 that is provided in the middle of the pressure side bypass passage 10 and upstream from the branch point of the discharge passage 11, opens and closes the pressure side bypass passage 10, an extension side logic valve 13, and a pressure side logic valve 16. And a control valve 17 for controlling the opening and closing of the motor.

  The rod side chamber R1 and the piston side chamber R2 are filled with a liquid such as hydraulic oil, and the tank 4 is filled with a gas in addition to the liquid. As the liquid, water or an aqueous solution can be used in addition to the hydraulic oil.

  The inside of the tank 4 is not particularly required to be in a pressurized state by compressing and filling a gas, but may be in a pressurized state.

  The hydraulic damper D is suitable for a seismic isolation device, and although not shown, for example, it is interposed between the ground and a structure together with an elastic body such as a ball isolator or a laminated rubber, and is incorporated in the seismic isolation device. However, the use of the hydraulic damper is not limited to this.

  Hereinafter, each part will be described. The cylinder 1 has a cylindrical shape, and the right end in FIG. 1 is closed by a lid 18, and an annular rod guide 19 is attached to the left end in FIG. A piston rod 3 slidably inserted into the cylinder 1 is slidably inserted into the inner periphery of the rod guide 19. The piston rod 3 is connected at one end to a piston 2 that is slidably inserted into the cylinder 1, and has the other end protruding outside the cylinder 1, and is movable with respect to the cylinder 2. Yes.

  1, the lid 18 that closes the other end, which is the left end in FIG. 1 and the right end of the cylinder 1, is not shown, but this hydraulic damper D is placed between the structure and the ground. A bracket is provided so that it can be attached. A detection rod 20 is attached to the piston rod 3 in parallel with the piston rod 3 via a connecting rod 21. The detection rod 20 is provided with a recess 20a in the center, and when the piston rod 3 moves relative to the cylinder 1 in the axial direction, the detection rod 20 also moves relative to the cylinder 1 in the axial direction. Yes.

  The piston 2 divides the inside of the cylinder 1 into the rod side chamber R1 and the piston side chamber R2 as described above, and is provided with the main extension side damping means 5 and the first main pressure side damping means 6 described above.

  In this embodiment, the main extension side damping means 5 is provided in the piston 2. Specifically, the main extension side damping means 5 is provided in the piston 2 and a main extension side passage 51 communicating with the rod side chamber R1 to the piston side chamber R2. A pressure regulating valve 52 and a relief valve 53 provided in parallel with the main extension side passage 51 are provided. Both the pressure regulating valve 52 and the relief valve 53 allow only the flow of liquid from the rod side chamber R1 toward the piston side chamber R2, and give resistance to the flow of liquid. As a result, the main extension side damping means 5 allows the liquid flow from the rod side chamber R1 to the piston side chamber R2, and can provide resistance to the liquid flow.

  The pressure regulating valve 52 has a characteristic such that the pressure loss is approximately proportional to the passing flow rate until the pressure difference between the rod side chamber R1 and the piston side chamber R2 reaches the valve opening pressure and the relief valve 53 is opened. The pressure loss is substantially proportional to the flow rate of the liquid passing through the main extension side passage 51. On the other hand, when the relief valve 53 is opened, the effective sectional area of the main extension side passage 51 increases. Therefore, the inclination of the flow rate pressure characteristic in the main extension side damping means 5 when the relief valve is opened indicates that the relief valve 53 is closed. It becomes small compared with the said characteristic when it exists in.

  In this embodiment, the first main pressure side damping means 6 is provided in the piston 2, and more specifically, is provided in the piston 2 and communicates the piston side chamber R2 with the rod side chamber R1. 61 and a pressure regulating valve 62 and a relief valve 63 provided in parallel with the first main pressure side passage 61. Both the pressure regulating valve 62 and the relief valve 63 allow only the flow of liquid from the piston side chamber R2 to the rod side chamber R1, and give resistance to the liquid flow. As a result, the first main pressure side damping means 6 allows the liquid flow from the piston side chamber R2 to the rod side chamber R1, and can provide resistance to the liquid flow.

  In the case of this embodiment, the second main pressure side damping means 7 includes a second main pressure side passage 71 that communicates the piston side chamber R2 with the tank 4, a pressure regulating valve 72 provided in parallel with the second main pressure side passage 71, and a relief. And a valve 73. Both the pressure regulating valve 72 and the relief valve 73 allow only the flow of liquid from the piston side chamber R2 to the tank 4 and provide resistance to the flow of liquid. Thereby, the second main pressure side damping means 7 allows the liquid flow from the piston side chamber R2 to the tank 4 and can provide resistance to the liquid flow.

  Similarly to the pressure regulating valve 52, the pressure regulating valves 62 and 72 also have characteristics such that the pressure loss is approximately proportional to the passage flow rate, and the flow rates in the first main pressure side damping means 6 and the second main pressure side damping means 7 The pressure characteristic indicates a characteristic that the inclination becomes smaller after the relief valves 63 and 73 are opened than before the valve is opened.

  The suction passage 8 includes a communication passage 81 that allows the tank 4 and the piston side chamber R2 to communicate with each other, and a check valve 82 that is provided in the middle of the communication passage 81 and that allows only a liquid flow from the tank 4 to the piston side chamber R2. I have. A volume of liquid corresponding to the volume of the piston rod 3 withdrawing from the cylinder 1 when the hydraulic damper D is extended is supplied into the cylinder 1 from the tank 4 through the suction passage 8. Compensation is performed.

  The extension side bypass passage 9 bypasses the main extension side damping means 5, that is, communicates the rod side chamber R1 and the piston side chamber R2 in parallel with the main extension side attenuation passage 51. In the middle of the extension side bypass path 9, the extension side logic valve 13 and the auxiliary extension side damping means 12 are provided in this order with the rod side chamber R1 upstream. The sub-extension side damping means 12 is a pressure regulating valve, and allows only the flow of liquid from the rod side chamber R1 to the piston side chamber R2. Like the pressure regulating valve 52, the pressure loss is approximately proportional to the passing flow rate. It has such characteristics.

  The extension side logic valve 13 includes an extension side valve element 131 that opens and closes the extension side bypass path 9 and a spring 132 as an extension side urging member that urges the extension side valve element 131 in a direction to close the extension side bypass path 9. The expansion side back pressure chamber 133 is provided on the back side of the expansion side valve element 131, that is, on the opposite passage side, and the expansion side pilot passage 134 that communicates the expansion side back pressure chamber 133 with the tank 4 is provided. The extension-side urging member may be a member other than the spring 132 as long as it can urge the extension-side valve body 131 and close the extension-side bypass passage 9.

The expansion side valve element 131 receives the pressure upstream of the expansion side bypass passage 9, that is, the pressure in the rod side chamber R1, on the front side, and the pressure in the expansion side back pressure chamber 133 is applied to the back side. It comes to work. Accordingly, when the extension side pilot passage 134 is in communication with the tank 4, the inside of the extension side back pressure chamber 133 becomes the tank pressure. When the rod side chamber R1 is compressed and the pressure in the rod side chamber R1 rises in this state, the rod side chamber In response to the pressure of R1, the expansion side valve element 131 moves in a direction in which the expansion side back pressure chamber 133 is compressed, and the expansion side logic valve 13 is opened. On the contrary, in the state where the expansion side pilot passage 134 is blocked and the communication with the tank 4 is blocked, even if the rod side chamber R1 is compressed and the pressure in the rod side chamber R1 rises, the expansion side back pressure chamber 133 Therefore, the expansion side back pressure chamber 133 cannot be compressed by the expansion side valve body 131, and the expansion side valve body 131 remains in the state where the expansion side bypass passage 9 is blocked and the expansion side logic valve 13 is closed. . The expansion side valve body 131 is provided with a throttle passage 131 a that guides the pressure upstream of the expansion side valve body 131 to the expansion side back pressure chamber 133. Accordingly, when the expansion side valve body 131 is retracted toward the expansion side back pressure chamber 133 and the expansion side bypass passage 9 is opened and the expansion side pilot passage 134 is blocked, the expansion side back pressure chamber 133 is blocked. Since the communication between the tank 4 and the tank 4 is interrupted, the pressure in the extension-side back pressure chamber 133 is increased, the extension-side valve body 131 is moved in a direction to shut off the extension-side bypass passage 9, and the extension-side logic valve 13 is Close the valve. As described above, the expansion side logic valve 13 is in a state in which the expansion side pilot passage 134 is opened and the expansion side back pressure chamber 133 communicates with the tank 4 so that the valve can be opened, and the rod side chamber R1 is compressed. When the pressure rises, the valve is opened, and conversely, when the expansion side pilot passage 134 is blocked and the communication between the expansion side back pressure chamber 133 and the tank 4 is cut off, the valve is closed. Although the throttle passage 131a is provided in the expansion side valve body 131, for example, the upstream side of the expansion side valve body 133 of the extension side bypass passage 9 communicates with the extension side back pressure chamber 131 instead of the throttle passage 131a. A throttle passage may be provided, or a check valve that allows only the flow of liquid from the upstream side of the extension side valve body 131 toward the extension side back pressure chamber 133 may be provided in the middle of the throttle passage. The check valve is provided so as not to prevent the valve closing operation of the expansion side valve body 131 when the expansion side logic valve 13 is closed. The pressure side bypass passage 10 bypasses the first main pressure side damping means 6, that is, communicates the piston side chamber R <b> 2 and the rod side chamber R <b> 1 in parallel with the first main pressure side damping passage 61. A discharge passage 11 branched from the pressure side bypass passage 10 and communicating the piston side chamber R2 with the tank 4 is provided.

  Then, with the piston side chamber R2 being upstream, a pressure side logic valve 16 is provided in the middle of the pressure side bypass passage 10 upstream of the branch point of the discharge passage 11, and a first auxiliary pressure side damping means 14 is provided downstream of the branch point. It has been. A second sub-pressure side damping means 15 is provided in the middle of the discharge passage 11. The first sub-pressure-side damping means 14 is a pressure regulating valve, and only allows the flow of liquid from the piston-side chamber R2 to the rod-side chamber R1, and like the pressure regulating valve 62, the pressure loss is approximately proportional to the passing flow rate. It has the characteristics to do. Further, the second sub-pressure side damping means 15 is also a pressure regulating valve, which allows only the flow of liquid from the piston side chamber R2 to the tank 4 and, like the pressure regulating valve 72, has a pressure loss with respect to the passing flow rate. It has characteristics that are approximately proportional.

  The pressure side logic valve 16 includes a pressure side valve body 161 that opens and closes the pressure side bypass path 10, a spring 162 as a pressure side biasing member that biases the pressure side valve body 161 in a direction to close the pressure side bypass path 10, and a pressure side valve body 161. A pressure-side back pressure chamber 163 provided on the back side, that is, the opposite passage side, and a pressure-side pilot passage 164 that communicates the pressure-side back pressure chamber 163 with the tank 4 are provided. The pressure-side biasing member may be a member other than the spring 162, and may be any member that can bias the pressure-side valve body 161 and close the pressure-side bypass passage 10.

  The pressure side valve body 161 receives the pressure upstream of the pressure side bypass passage 10, that is, the pressure of the piston side chamber R2, on the front side, and the pressure in the pressure side back pressure chamber 163 acts on the back side. It has become. Therefore, in the state where the pressure side pilot passage 164 communicates with the tank 4, the inside of the pressure side back pressure chamber 163 becomes the tank pressure. In this state, when the piston side chamber R2 is compressed and the pressure in the piston side chamber R2 rises, In response to the pressure, the pressure side valve body 161 moves in a direction to compress the pressure side back pressure chamber 163 and the pressure side logic valve 16 is opened.

  On the contrary, in the state where the pressure side pilot passage 164 is blocked and the communication with the tank 4 is prevented, even if the piston side chamber R2 is compressed and the pressure in the piston side chamber R2 rises, the liquid in the pressure side back pressure chamber 163 increases. Since the pressure side valve body 161 cannot compress the pressure side back pressure chamber 163, the pressure side valve body 161 remains disconnected from the pressure side bypass 10 and the pressure side logic valve 16 is closed. The pressure side valve body 161 is provided with a throttle passage 161 a that guides the pressure upstream of the pressure side valve body 161 to the pressure side back pressure chamber 163. Therefore, when the pressure side valve body 161 is retracted toward the pressure side back pressure chamber 163 and the pressure side bypass passage 10 is opened, and the pressure side pilot passage 164 is blocked, the pressure side back pressure chamber 163 and the tank 4 Since the communication is blocked, the pressure in the pressure-side back pressure chamber 163 increases, the pressure-side valve body 161 is moved in a direction to block the pressure-side bypass passage 10, and the pressure-side logic valve 16 is closed. Thus, the pressure side logic valve 16 also exhibits the same operation as that of the expansion side logic valve 13. Specifically, the pressure side pilot passage 164 is opened and the pressure side back pressure chamber 163 is connected to the tank 4. In this state, the valve side can be opened, and the piston side chamber R2 is compressed and the valve is opened when the pressure rises. Conversely, the pressure side pilot passage 164 is blocked and the pressure side back pressure chamber 163 communicates with the tank 4. If it is cut off, it will close. Even in the pressure side logic valve 16, the throttle passage 161a is provided in the pressure side valve body 161. For example, instead of the throttle passage 161a, the upstream side of the expansion side valve body 161 of the pressure side bypass passage 10 is disposed on the pressure side. A throttle passage communicating with the back pressure chamber 162 may be provided, and a check valve that allows only the flow of liquid from the upstream side of the pressure side valve body 161 toward the pressure side back pressure chamber 163 may be provided in the middle of the throttle passage. It may be. The check valve is provided so as not to prevent the closing operation of the pressure side valve body 161 when the pressure side logic valve 16 is closed.

  As described above, the expansion side logic valve 13 is opened when the expansion side pilot passage 134 communicates with the tank 4, and is closed when the expansion side pilot passage 134 is shut off. 16 is also opened when the pressure side pilot passage 164 communicates with the tank 4 and is closed when the pressure side pilot passage 164 is shut off. Therefore, the opening / closing control of the expansion side logic valve 13 and the pressure side logic valve 16 is performed. The control valve 17 that opens and closes the expansion side pilot passage 134 and the compression side pilot passage 164 is used.

  Specifically, since both the expansion side pilot passage 134 and the pressure side pilot passage 164 communicate with the tank 4, a passage 200 in which the expansion side pilot passage 134 and the compression side pilot passage 134 are combined together is provided on the tank side. The control valve 17 is provided in the middle of the passage 200 shared by 164. In this way, the expansion side pilot passage 134 also includes the pressure side pilot passage 164 from the middle to the tank 4 as one passage 200, and the control valve 17 is provided in the passage 200, so that the control valve 17 is connected to the expansion side pilot passage 134. There is an advantage that it is not necessary to provide the pressure side pilot passage 164 one by one.

  The control valve 17 opens and closes the passage 200 in conjunction with the detection rod 20 attached to the piston rod 3, and when the piston rod 3 strokes a predetermined amount or more from the neutral position, the expansion side logic valve 13 and the pressure side logic valve. 16 is closed.

  Specifically, the control valve 17 is provided on the cylinder 1 side, and can transmit an external force to the control valve body 171 having the cutoff position 173 and the communication position 172, and the control valve body 171. A switching lever 174 that enables switching between opening and closing of the valve body 17 and a spring 175 as a control valve biasing means that biases the control valve body 171 and abuts the switching lever 174 against the detection rod 20 are provided. . The control valve biasing member may be a member other than the spring 175, and may be any member that can bias the control valve body 171 and close the passage 200.

  A roller 174a is provided at the detection rod side end of the switching lever 174. When the piston rod 3 moves relative to the cylinder 1 in the axial direction, that is, when the hydraulic damper D exhibits expansion / contraction operation, the cylinder A roller 174 a in the switching lever 174 of the control valve 17 attached to the 1 side travels on the detection rod 20 that moves relative to the cylinder 1 in the axial direction together with the piston rod 3. The recess 20a described above is provided in the portion of the detection rod 20 where the roller 174a travels, and the control valve body 171 is biased by the spring 175 when the roller 174a travels in the recess 20a. The control valve 17 takes the communication position 172, and the control valve 17 takes the blocking position 173 when the roller 174a is in contact with other than the recess 20a. Therefore, in a state where the switching lever 174 is in contact with the recess 20a provided at the center of the detection rod 20, the control valve 17 opens the expansion side pilot passage 134 and the pressure side pilot passage 164 to expand the expansion side back pressure chamber 133 and the pressure side back pressure. In a state where the chamber 163 is communicated with the tank 4 and the switching lever 174 is in contact with a portion where the concave portions 20a on both sides of the concave portion 20a of the detection rod 20 are not provided, the control valve 17 causes the expansion side pilot passage 134 and the pressure side pilot passage 164 to move. The extension side back pressure chamber 133 and the pressure side back pressure chamber 163 are closed without being communicated with the tank 4.

  When the stroke amount from the neutral position of the piston rod 3 is within the predetermined amount, the switching lever 174 always enters the recess 20a of the detection rod 20 so that the control valve 17 is opened, and the piston rod 3 When the stroke amount 3 from the neutral position is equal to or greater than a predetermined amount, the switching lever 174 contacts either one of the two sides of the concave portion 20a on the detection rod 20, that is, the portion where the concave portion 20a is not provided. In contact with each other, the control valve 17 is closed. As a result, when the piston rod 3 strokes a predetermined amount or more from the neutral position, the expansion side logic valve 13 and the pressure side logic valve 16 can be closed by the control valve 17. As shown in the figure, the control valve 17 is provided with a detent mechanism on the switching lever 174. As described above, the control valve 17 changes from the open state where the communication position 172 is taken to the closed state where the cut-off position 173 is taken. When switched, the control valve 17 maintains the shut-off position and maintains the closed state. Further, after the control valve 17 is closed, the detent mechanism can be manually operated to return to the valve open state. Since the roller 174a is provided, the switching lever 174 can smoothly travel on the detection rod 20, and the hydraulic damper D can be smoothly expanded and contracted without hindering relative movement of the piston rod 3 with respect to the cylinder 1. However, it is also possible to make the roller 174a contact with the detection rod 20 without providing the roller 174a. In that case, the tip of the switching lever 174 is preferably a spherical surface or an arcuate surface.

  The neutral position of the piston rod 3, that is, the position of the piston rod 3 relative to the cylinder 1 in the state where no external force is input is attached to the seismic isolation device, etc. The position of the piston rod 3 relative to the cylinder 1 in the center of the range in which the piston 2 strokes relative to the cylinder 1 is set, but the neutral position can be set arbitrarily, and the control valve 17 can be opened. The predetermined amount, which is the stroke amount of the piston rod 3 that switches from the valve state to the valve closed state, can also be set arbitrarily. Therefore, for example, the predetermined amount that is the switching point from the opening to the closing of the control valve 17 can be set to be different between the expansion side and the contraction side of the hydraulic damper D, and the neutral position and the predetermined amount can be set. Can be set by adjusting the axial length of the recess 20a of the detection rod 20 and the installation position of the detection rod 20 in the recess 20a.

  In this case, the detection rod 20 is provided with a recess 20a, and the control valve 17 is opened when the recess 20a comes into contact with the switching lever 174. 1 is employed, and the control valve body 171 shown in FIG. 1 has a structure in which the communication position 172 and the shut-off position 173 are arranged upside down. When the switching lever 174 comes into contact with the projection, It is also possible for 17 to open.

  The operation of the hydraulic damper D configured as described above will be described. First, the case where the stroke amount from the neutral position of the piston rod 3 is less than a predetermined amount will be described. In this case, as described above, the control valve 17 is in the open state and connects the expansion side pilot passage 134 and the pressure side pilot passage 164 to the tank 4, so that the expansion side logic valve 13 and the pressure side logic valve 16 are opened. Make it operable. Therefore, in this situation, when the hydraulic damper D is extended, the liquid in the rod side chamber R1 to be compressed moves to the expanding piston side chamber R2 via the main extension side damping means 5 and the sub extension side damping means 12. Then, an amount of liquid corresponding to the volume with which the piston rod 3 retreats from the cylinder 1 is supplied from the tank 4 to the piston-side chamber R2 through the suction passage 8. Therefore, in this case, when the piston speed is low and the differential pressure between the rod side chamber R1 and the piston side chamber R2 is low enough not to reach the valve opening pressure of the relief valve 53, the liquid in the rod side chamber R1 is discharged from the pressure regulating valve 52 and the pressure regulating valve. Therefore, the hydraulic damper D has a low damping force gradient as indicated by the line a in FIG. Further, when the piston speed is high and the differential pressure between the rod side chamber R1 and the piston side chamber R2 reaches the valve opening pressure of the relief valve 53, the liquid in the rod side chamber R1 is attenuated by the secondary expansion side which is the pressure regulating valve 52 and the pressure regulating valve. Since it moves to the piston side chamber R2 through the relief valve 53 other than the means 12, the rate of increase of the damping force of the hydraulic damper D with respect to the piston speed decreases as shown by the line b in FIG.

  When the expansion side logic valve 13 and the pressure side logic valve 16 are openable and the hydraulic damper D is contracted, the liquid in the piston side chamber R2 to be compressed first enters the expanding rod side chamber R1. The liquid moves through the main pressure side damping means 6 and the first auxiliary pressure side damping means 14, and an amount of liquid corresponding to the volume into which the piston rod 3 enters the cylinder 1 is added to the second main pressure side damping means 7 and the second auxiliary pressure side damping means 7. It is discharged from the piston side chamber R2 to the tank 4 via the pressure side damping means 15. Therefore, in this case, if the piston speed is low and the relief valves 63 and 73 are not opened, the liquid in the piston side chamber R2 is the pressure regulating valves 62 and 72 and the first sub pressure side damping means 14 and the second sub pressure side that are pressure regulating valves. Since it moves to the rod side chamber R1 and the tank 4 via the pressure side damping means 15, the hydraulic damper D exhibits a damping characteristic with a low damping force gradient, as indicated by a line a in FIG. Further, in a state where the piston speed is high and the relief valves 63 and 73 are opened, the liquid in the piston side chamber R2 is not limited to the pressure regulating valves 62 and 72 and the auxiliary expansion side damping means 14 and 15 which are pressure regulating valves. Since it passes through 63 and 73 and moves to the rod side chamber R1 and the tank 4, the rate of increase of the damping force of the hydraulic damper D with respect to the piston speed decreases as shown by the line b in FIG.

  In the case of this hydraulic damper D, the pressure regulating valves 52, 62, 72 and the relief valves 53, 63 are set so that the damping characteristics when the expansion operation is performed and the damping characteristics when the contraction operation are performed so as to be suitable for the seismic isolation device. 73, characteristics of the pressure regulating valve that is the secondary extension side damping means 12, the pressure regulating valve that is the first secondary pressure side damping means 14, and the pressure regulating valve that is the second secondary pressure side damping means 15 are set. Needless to say, the damping characteristic at the time of the expansion operation of the hydraulic damper D and the damping characteristic at the time of the contraction operation can be set differently.

  On the other hand, when the stroke amount from the neutral position of the piston rod 3 is equal to or larger than the predetermined amount, the control valve 17 is closed as described above, and the expansion side pilot passage 134, the pressure side pilot passage 164 and the tank 4 are closed. Therefore, the expansion side logic valve 13 and the pressure side logic valve 16 are closed. Therefore, in this situation, when the hydraulic damper D is extended, the liquid in the rod side chamber R1 to be compressed moves to the expanding piston side chamber R2 only through the main extension side damping means 5, and the piston rod 3 is moved. An amount of liquid commensurate with the volume withdrawing from the cylinder 1 is supplied from the tank 4 to the piston side chamber R2 through the suction passage 8. Therefore, in this case, even if the piston speed is low and the differential pressure between the rod side chamber R1 and the piston side chamber R2 is low enough not to reach the valve opening pressure of the relief valve 53, the liquid in the rod side chamber R1 is only the pressure regulating valve 52. The hydraulic damper D has a characteristic indicated by a line a when the stroke amount from the neutral position of the piston rod 3 is less than a predetermined amount as shown by a line c in FIG. In comparison, it exhibits damping force characteristics with a high damping force gradient. Even in a state where the piston speed is high and the differential pressure between the rod side chamber R1 and the piston side chamber R2 reaches the valve opening pressure of the relief valve 53, the liquid in the rod side chamber R1 passes through the secondary extension side damping means 12 which is a pressure regulating valve. Without passing through the pressure regulating valve 52 and the relief valve 53 and moving to the piston-side chamber R2, as shown by the line d in FIG. Compared to the characteristic indicated by the line b when the stroke amount from the neutral position of the piston rod 3 is less than the predetermined amount, the hydraulic damper D exhibits a high damping force.

  When the expansion side logic valve 13 and the pressure side logic valve 16 are closed and the hydraulic damper D is contracted, the liquid in the piston side chamber R2 to be compressed is transferred to the expanding rod side chamber R1 on the first main pressure side. The liquid moves only through the damping means 6, and further, an amount of liquid commensurate with the volume of the piston rod 3 entering the cylinder 1 is discharged from the piston side chamber R 2 to the tank 4 through only the second main pressure side damping means 7. The Therefore, in this case, if the piston speed is low and the relief valves 63 and 73 are not opened, the liquid in the piston side chamber R2 moves to the rod side chamber R1 and the tank 4 only through the pressure regulating valves 62 and 72. As shown by the line c in FIG. 2, the pressure damper D exhibits a higher damping force than the characteristic indicated by the line a when the stroke amount from the neutral position of the piston rod 3 is less than a predetermined amount. . Even in a state where the piston speed is high and the relief valves 63 and 73 are opened, the liquid in the piston side chamber R2 does not pass through the auxiliary extension side damping means 14 and 15, and the pressure regulating valves 62 and 72 and the relief valves 63, Since only 73 passes through the rod side chamber R1 and the tank 4, the rate of increase of the damping force of the hydraulic damper D with respect to the piston speed decreases as shown by the line d in FIG. Compared to the characteristic indicated by the line b when the stroke amount from the neutral position is less than the predetermined amount, the hydraulic damper D exhibits a high damping force.

  As described above, the hydraulic damper D of the present invention can reduce the damping force gradient when the stroke amount from the neutral position of the piston rod 3 is less than a predetermined amount, When the stroke amount is equal to or greater than the predetermined amount, the damping force gradient is increased, so that a damping characteristic suitable for a seismic isolation device or the like can be realized. In particular, it is most suitable for seismic isolation devices used for high-rise buildings built in narrow spaces.

  In the hydraulic damper D of the present invention, liquid is supplied from the compressed rod side chamber R1 to the enlarged piston side chamber R2 during the extension operation, so that the amount of liquid sucked into the piston side chamber R2 from the tank 4 is the cylinder 1 Therefore, the amount of suction of the liquid does not occur in the cylinder 1 and the damping force can be output as set, effectively controlling the structure. Can shake. That is, according to the hydraulic damper D of the present invention, a stable damping force can be exhibited while realizing a damping characteristic suitable for a seismic isolation device.

  Further, the expansion side bypass passage 9 is opened and closed by the expansion side logic valve 13, the pressure side bypass passage 16 is opened and closed by the compression side logic valve 16, and the opening and closing control of the expansion side logic valve 13 and the pressure side logic valve 16 is controlled by the expansion side logic. A control valve 17 provided in the middle of a pressure side pilot passage 164 for communicating the expansion side back pressure chamber 133 in the valve 13 with the tank 4 and a pressure side pilot passage 164 for communicating the pressure side back pressure chamber 163 in the pressure side logic valve 16 with the tank 4. Therefore, the expansion side logic valve 13 and the pressure side logic valve 16 to which a large pressure acts can be opened and closed without difficulty, and the control valve 17 can be switched according to the position of the piston rod 3 with respect to the cylinder 1. The opening / closing control of the expansion side logic valve 13 and the pressure side logic valve 16 can be performed mechanically with high accuracy.

  A detection rod 20 provided outside the cylinder 1 is provided on the piston rod 3, and a switching lever 174 that operates the control valve body 171 of the control valve 17 when the piston rod 3 moves relative to the cylinder 1 in the axial direction. Since the control valve 17 is switched by providing the recess 20a or the projection in the portion that travels on the detection rod 20, the switching from the low damping characteristic to the high damping characteristic can be performed accurately at the position of the piston rod 3. In the hydraulic damper D configured in this way, the damping characteristic is adjusted by adjusting the length or position of the concave portion 20a or the convex portion of the detection rod 20 and the mounting position of the detection rod 20 with respect to the piston rod 3. It is possible to easily set the stroke amount from the neutral position and the neutral position of the piston rod 3 to be switched. In the case of the hydraulic damper D of this embodiment, when the control valve 17 is switched from the open state to the closed state, the detent mechanism maintains the closed state, so that the piston rod 3 has a stroke amount from the neutral position. High attenuation characteristics can be maintained even if becomes less than a predetermined amount.

  The main extension side damping means 5, the first main pressure side damping means 6 and the second main pressure side damping means 7 all have pressure regulating valves 52, 62, 72 and relief valves 53, 63, 73. Since the expansion side damping means 12, the first auxiliary pressure side attenuation means 14, and the second auxiliary pressure side attenuation means 15 are all pressure regulating valves, the relief valves 52, 62, 72 are provided for any attenuation characteristics that are switched between high and low. When the valve is opened, the damping coefficient becomes low. When the piston speed is low, sufficient damping force can be exerted. When the piston speed is high, the damping force does not become excessive, and the damping is suitable for a seismic isolation device. Characteristics can be realized.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Piston rod 4 Tank 5 Main extension side damping means 6 First main pressure side damping means 7 Second main pressure side damping means 8 Suction passage 9 Extension side bypass path 10 Pressure side bypass path 11 Discharge path 12 Sub extension side damping means 13 Extension side logic valve 131 Extension side valve element 132 Spring 133 as extension side biasing member Extension side back pressure chamber 134 Extension side pilot passage 14 First auxiliary pressure side damping means 15 Second auxiliary pressure side damping means 16 Pressure side logic valve 161 Pressure side Valve body 162 Spring 163 as pressure side biasing member Pressure side back pressure chamber 164 Pressure side pilot passage 17 Control valve 171 Control valve body 174 Switching lever 175 Spring 20 as control valve biasing means Detection rods 52, 62, 72 Pressure regulating valves 53, 63, 73 Relief valve D Hydraulic damper R1 Rod side chamber R2 Piston side chamber

Claims (4)

A cylinder, a piston slidably inserted into the cylinder, a piston rod movably inserted into the cylinder and connected at one end to the piston, and a rod partitioned by the piston in the cylinder A side chamber, a piston side chamber, a tank, a main extension side damping means for allowing a flow of liquid from the rod side chamber to the piston side chamber and giving resistance to the flow of the liquid, and a liquid from the piston side chamber to the rod side chamber First main pressure side damping means for allowing the flow of the liquid and giving resistance to the flow of the liquid, and second main pressure side damping for allowing the flow of liquid from the piston side chamber to the tank and giving resistance to the flow of the liquid And a suction damper that allows a liquid to flow from the tank to the piston side chamber. An extension side bypass passage that bypasses the rod side chamber and the piston side chamber, bypasses the first main pressure side damping means, bypasses the rod side chamber and the piston side chamber, and the pressure side bypass passage bypasses the means. A discharge passage that branches off from the pressure side bypass passage and communicates with the tank, and is provided in the middle of the extension side bypass passage to allow the flow of liquid from the rod side chamber to the piston side chamber and to resist the flow of the liquid. A secondary extension side damping means for supplying, an extension side logic valve provided in the middle of the extension side bypass passage to open and close the extension side bypass passage, and in the middle of the pressure side bypass passage and downstream from the branch point of the discharge passage A first auxiliary pressure side damping means for allowing a flow of liquid from the piston side chamber to the rod side chamber and providing resistance to the flow of the liquid; A second auxiliary pressure side damping means that is provided in the piston side chamber to allow the flow of the liquid from the piston side chamber to the tank and provides resistance to the flow of the liquid, and in the middle of the pressure side bypass path and the branch of the discharge passage A pressure-side logic valve provided upstream of the point for opening and closing the pressure-side bypass path, and a control valve for controlling the opening and closing of the extension-side logic valve and the pressure-side logic valve, the control valve having the piston rod from a neutral position A hydraulic damper characterized in that the extension side logic valve and the pressure side logic valve are closed when a stroke exceeds a predetermined amount. The extension side logic valve includes: an extension side valve body that opens and closes the extension side bypass path; an extension side biasing member that biases the extension side valve body in a direction to close the extension side bypass path; and the extension side valve. An extension side back pressure chamber provided on the back side of the body, and an extension side pilot passage communicating the extension side back pressure chamber to the tank,
The pressure side logic valve is provided on the back side of the pressure side valve body, a pressure side valve body that opens and closes the pressure side bypass path, a pressure side biasing member that biases the pressure side valve body in a direction to close the pressure side bypass path, and A pressure side back pressure chamber, and a pressure side pilot passage communicating the pressure side back pressure chamber to the tank,
The control valve is provided in the middle of the extension side pilot passage and the pressure side pilot passage, and when the piston rod strokes a predetermined amount or more from a neutral position, the extension side pilot passage and the pressure side pilot passage are cut off to extend the extension side. 2. The hydraulic damper according to claim 1, wherein the logic valve and the pressure side logic valve are closed. The piston rod includes the detection rod provided outside the cylinder,
The control valve includes: a control valve body that opens and closes the extension side pilot passage and the pressure side pilot passage; a switching lever that switches opening and closing of the control valve body; and the control valve body that energizes the control valve body and detects the switching lever. A control valve biasing means for contacting the
The hydraulic damper according to claim 2, wherein a recess or a projection is provided in a traveling portion of the switching lever on the detection rod, and the control valve is switched during a stroke of the piston rod. The main extension side damping means, the first main pressure side damping means, and the second main pressure side damping means each have a pressure regulating valve and a relief valve, and the sub extension side damping means, the first secondary pressure side damping means, and the second secondary pressure side damping means. The hydraulic damper according to any one of claims 1 to 3, wherein each of the compression side damping means is a pressure regulating valve.

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