Hydraulic damper, hydraulic adjustment device, and method for controlling a hydraulic damper

Abstract

The structure of the hydraulic damper is simplified while improving energy absorption. [Solution] The hydraulic adjustment module 3 of the hydraulic damper 1 includes an accumulator 38 for releasing the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22; a mutual on / off control valve that switches between opening to allow the movement of hydraulic fluid from the first hydraulic chamber 21 to the second hydraulic chamber 22 and from the second hydraulic chamber 22 to the first hydraulic chamber 21, and closing to prohibit the movement of hydraulic fluid; a first on / off control valve that switches between opening to allow the movement of hydraulic fluid from the first hydraulic chamber 21 to the accumulator 38 and closing to prohibit the movement of hydraulic fluid; and a second on / off control valve 32 that switches between opening to allow the movement of hydraulic fluid from the second hydraulic chamber 22 to the accumulator 38 and closing to prohibit the movement of hydraulic fluid.

Description

[Technical Field]

[0001] The present invention relates to a hydraulic damper, a hydraulic adjustment device, and a method for controlling a hydraulic damper. [Background technology]

[0002] Hydraulic dampers are used as seismic damping devices to reduce building sway. Conventional hydraulic dampers are equipped with an adjustment valve to maintain a constant damping constant. Dampers that further improve the performance of hydraulic dampers in maintaining a constant damping constant are disclosed in Patent Documents 1 to 3. The hydraulic dampers disclosed in Patent Documents 1 to 3 include a cylinder, a piston that reciprocates inside the cylinder, hydraulic chambers provided on both sides of the piston, and an on / off control valve provided in the flow path connecting the two hydraulic chambers. The hydraulic dampers disclosed in Patent Documents 1 and 2 aim to improve the energy absorption of the hydraulic damper by controlling the opening and closing of the on / off control valve. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 3397199 [Patent Document 2] Patent No. 4358091 [Patent Document 3] Patent No. 6000872 [Overview of the project] [Problems that the invention aims to solve]

[0004] The hydraulic damper disclosed in Patent Document 3 aims to further improve energy absorption compared to the hydraulic dampers disclosed in Patent Documents 1 and 2 by repurposing regenerated energy to reduce vibration. Therefore, the hydraulic damper disclosed in Patent Document 3 further includes an auxiliary hydraulic tank in addition to the cylinder, piston, and on / off control valve. As a result, the hydraulic damper disclosed in Patent Document 3 has a more complex mechanism than hydraulic dampers that do not have an auxiliary hydraulic tank, such as the hydraulic dampers disclosed in Patent Documents 1 and 2, which may increase costs. Furthermore, because the hydraulic damper disclosed in Patent Document 3 requires a relatively large auxiliary hydraulic tank, the installation locations of the hydraulic damper may be limited.

[0005] Therefore, the present invention aims to provide a hydraulic damper, a hydraulic adjustment device, and a method for controlling a hydraulic damper that can improve energy absorption while simplifying the structure of the hydraulic damper. [Means for solving the problem]

[0006] One embodiment of the present invention comprises: [1] a cylinder having an internal space filled with hydraulic fluid; a piston disposed inside the cylinder, dividing the internal space into a first hydraulic chamber and a second hydraulic chamber, and moving reciprocally inside the cylinder; and a hydraulic adjustment unit connected to the first hydraulic chamber and the second hydraulic chamber, respectively, wherein the hydraulic adjustment unit is connected to the first hydraulic chamber via a first open passage and to the second hydraulic chamber via a second open passage, and includes a pressure release unit for releasing the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber, and a mutual passage having one end connected to the first hydraulic chamber and the other end connected to the second hydraulic chamber. A hydraulic damper comprising: a mutual on / off control valve provided to mutually switch between opening to allow the movement of hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber and from the second hydraulic chamber to the first hydraulic chamber, and closing to prohibit the movement of hydraulic fluid; a first on / off control valve provided in the first open passage to mutually switch between opening to allow the movement of hydraulic fluid from the first hydraulic chamber to the pressure release section and closing to prohibit the movement of hydraulic fluid; and a second on / off control valve provided in the second open passage to mutually switch between opening to allow the movement of hydraulic fluid from the second hydraulic chamber to the pressure release section and closing to prohibit the movement of hydraulic fluid.

[0007] One configuration of a hydraulic damper includes a mutual opening / closing control valve, a first opening / closing control valve, and a second opening / closing control valve. In this configuration, for example, when the hydraulic pressure in the high-pressure side first hydraulic chamber begins to decrease, the mutual opening / closing control valve can be opened. As a result, the hydraulic fluid in the high-pressure side first hydraulic chamber moves to the low-pressure side second hydraulic chamber, allowing a portion of the energy stored in the first hydraulic chamber to be directly transferred to the second hydraulic chamber. Consequently, there is no need to provide additional hydraulic circuit elements to regenerate the energy stored in the first hydraulic chamber, thus simplifying the hydraulic circuit configuration. Furthermore, the hydraulic adjustment unit can lower the pressure in the high-pressure side first hydraulic chamber to below the pressure in the second hydraulic chamber by opening the first opening / closing control valve after closing the mutual opening / closing control valve. The resulting differential pressure between the first and second hydraulic chambers contributes to further increasing the amount of earthquake energy absorbed by the building. In other words, improving energy absorption by offsetting the load of the hydraulic damper can be achieved with a simple configuration.

[0008] One embodiment of the present invention is [2] "a hydraulic damper as described in [1] above, wherein the hydraulic adjustment unit switches between a first hydraulic circuit configuration in which the mutual opening / closing control valve is closed, the first opening / closing control valve is closed, and the second opening / closing control valve is closed; a second hydraulic circuit configuration in which the mutual opening / closing control valve is open, the first opening / closing control valve is closed, and the second opening / closing control valve is closed; and a third hydraulic circuit configuration in which the mutual opening / closing control valve is closed, one of the first opening / closing control valve and the second opening / closing control valve is open, and the other is closed." Even with this configuration, the amount of energy absorbed can be appropriately improved.

[0009] One embodiment of the present invention is [3] "the hydraulic damper described in [2] above, wherein the hydraulic adjustment unit switches in the order of the first hydraulic circuit configuration, the second hydraulic circuit configuration, and the third hydraulic circuit configuration." Even with this configuration, the amount of energy absorbed can be appropriately improved.

[0010] One embodiment of the present invention is [4] "a hydraulic damper according to [2] or [3] above, wherein the hydraulic adjustment unit switches between the first hydraulic circuit configuration, the second hydraulic circuit configuration and the third hydraulic circuit configuration based on the pressure of the first hydraulic chamber and the pressure of the second hydraulic chamber." In this case, the first hydraulic circuit configuration, the second hydraulic circuit configuration and the third hydraulic circuit configuration can be switched between each other without, for example, being based on the direction of movement of the piston.

[0011] One embodiment of the present invention is [5] "a hydraulic damper as described in [4] above, wherein the hydraulic adjustment unit configures the first hydraulic circuit when the pressure in the first hydraulic chamber is increasing in response to the movement of the piston, switches from the first hydraulic circuit configuration to the second hydraulic circuit configuration in which the mutual on / off control valve is open and the first on / off control valve and the second on / off control valve are closed when the direction of movement of the piston is reversed, and configures the third hydraulic circuit configuration in which the first on / off control valve is open and the second on / off control valve is closed when the differential pressure between the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber becomes smaller than a threshold." Even with this configuration, the amount of energy absorbed can be appropriately improved.

[0012] Another embodiment of the present invention is a hydraulic adjustment device for a hydraulic damper comprising: a cylinder having an internal space filled with hydraulic fluid; a piston disposed inside the cylinder and dividing the internal space into a first hydraulic chamber and a second hydraulic chamber, and moving back and forth inside the cylinder, the device comprising: a pressure release section connected to the first hydraulic chamber via a first open passage and connected to the second hydraulic chamber via a second open passage for releasing the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber; and a mutual passage provided, one end of which is connected to the first hydraulic chamber and the other end of which is connected to the second hydraulic chamber, the first hydraulic chamber The hydraulic adjustment device comprises: a mutual on / off control valve that switches between opening to allow the movement of hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber and from the second hydraulic chamber to the first hydraulic chamber, and closing to prohibit the movement of hydraulic fluid; a first on / off control valve provided in the first open passage that switches between opening to allow the movement of hydraulic fluid from the first hydraulic chamber to the pressure release section and closing to prohibit the movement of hydraulic fluid; and a second on / off control valve provided in the second open passage that switches between opening to allow the movement of hydraulic fluid from the second hydraulic chamber to the pressure release section and closing to prohibit the movement of hydraulic fluid. This hydraulic adjustment device also makes it possible to improve energy absorption while simplifying the structure of the hydraulic damper.

[0013] A further embodiment of the present invention is [7] "a method for controlling a hydraulic damper comprising a cylinder having an internal space filled with hydraulic fluid, and a piston disposed inside the cylinder, dividing the internal space into a first hydraulic chamber and a second hydraulic chamber, and moving back and forth inside the cylinder, the method comprising: a first step of prohibiting the outflow of the hydraulic fluid from the first hydraulic chamber and the second hydraulic chamber when the pressure in the first hydraulic chamber is increasing in response to the movement of the piston; a second step of allowing the movement of the hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber when the direction of movement of the piston is reversed; and a third step of prohibiting the movement of the hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber and releasing the pressure in the first hydraulic chamber when the differential pressure between the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber becomes less than a threshold." This method for controlling a hydraulic damper also makes it possible to improve energy absorption while simplifying the structure of the hydraulic damper. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a hydraulic damper, a hydraulic adjustment device, and a method for controlling a hydraulic damper that can improve energy absorption while simplifying the structure of the hydraulic damper. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 shows an example of a hydraulic damper according to the embodiment installed in a building. [Figure 2] Figure 2 shows an example of the hydraulic circuit of the hydraulic damper shown in Figure 1. [Figure 3] Figure 3 shows an example of a specific cross-sectional structure of the hydraulic damper shown in Figure 2. [Figure 4]Fig. 4(a) is a diagram schematically showing a building structure part and a seismic isolation structure part in the first state. Fig. 4(b) is a diagram schematically showing a hydraulic damper in the first state. Fig. 4(c) is a mechanical model showing the hydraulic damper in the first state. Fig. 4(d) is a diagram schematically showing a building structure part and a seismic isolation structure part in the second state. Fig. 4(e) is a diagram schematically showing a hydraulic damper in the second state. Fig. 4(f) is a mechanical model showing the hydraulic damper in the second state. Fig. 4(g) is a diagram schematically showing a building structure part and a seismic isolation structure part in the third state. Fig. 4(h) is a diagram schematically showing a hydraulic damper in the third state. Fig. 4(i) is a mechanical model showing the hydraulic damper in the third state. [Figure 5] Fig. 5(a) is a diagram schematically showing a building structure part and a seismic isolation structure part in the fourth state. Fig. 5(b) is a diagram schematically showing a hydraulic damper in the fourth state. Fig. 5(c) is a mechanical model showing the hydraulic damper in the fourth state. Fig. 5(d) is a diagram schematically showing a building structure part and a seismic isolation structure part in the fifth state. Fig. 5(e) is a diagram schematically showing a hydraulic damper in the fifth state. Fig. 5(f) is a mechanical model showing the hydraulic damper in the fifth state. [Figure 6] Figs. 6(a), 6(b) and 6(c) are graphs showing the relationship between the displacement generated in the body connection part and the internal load. [Figure 7] Fig. 7 is a flowchart diagram showing an example of a method for controlling a hydraulic damper. [Figure 8] Fig. 8 is a diagram showing the hydraulic circuit of the hydraulic damper according to the first embodiment. [Figure 9] Fig. 9 is a diagram showing the hydraulic circuit of the hydraulic damper according to the second embodiment. [Figure 10] Fig. 10 is a diagram showing the hydraulic circuit of the hydraulic damper according to the third embodiment. [Figure 11] Fig. 11 is a diagram showing the hydraulic circuit of the hydraulic damper according to the fourth embodiment. [Figure 12] Fig. 12 is a diagram showing the hydraulic circuit of the hydraulic damper according to the fifth embodiment. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described in detail below with reference to the attached drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0017] As shown in Figure 1, the hydraulic damper 1 (oil damper) of this embodiment is applied to a building 100. The hydraulic damper 1 is installed, for example, on any floor (between floors) of the building 100. Figure 1 shows a simplified part of the building 100. The building 100 is composed of columns 101a and 101b that are provided in the vertical direction, and beams 102a and 102b that are stretched between the columns 101a and 101b. The upper end of a brace 103a is connected to the connection between the upper beam 102a and column 101a. The part where the upper beam 102a and brace 103a are connected to each other is called the structural connection part 110c. Furthermore, the part where the lower beam 102b and column 101a are connected to each other is called the structural connection part 110d. The upper end of a brace 103b is connected to the connection between beam 102a and column 101b. The lower ends of braces 103a and 103b are connected to each other. The part where the lower ends of braces 103a and 103b are connected to each other is called the brace connection section 103c. A hydraulic damper 1 is provided between this brace connection section 103c and the column 101b. More specifically, the hydraulic damper 1 has a first end 1a connected to the brace connection section 103c and a second end 1b connected to the column 101b. In the following description, the columns 101a, 101b and beams 102a, 102b are collectively referred to as the building structure section 110. Furthermore, the braces 103a, 103b and the hydraulic damper 1 are collectively referred to as the seismic damping structure section 120.

[0018] For example, when a building 100 is subjected to lateral shaking by an external vibrational force F100 such as an earthquake or wind, the horizontal position of the upper beam 102a shifts relative to the lower beam 102b (see Figure 4(d)). The hydraulic damper 1 absorbs the energy that causes this horizontal shift. As a result, this horizontal shift occurring in the building structure 110 can be suppressed. The hydraulic damper 1 will be described in more detail below.

[0019] Figure 2 is a schematic diagram showing the configuration of the hydraulic damper 1. Figure 3 is an example of a specific configuration of the hydraulic damper 1 shown in Figure 2. The hydraulic damper 1 includes a damper module 2 and a hydraulic adjustment module 3 (hydraulic adjustment section, hydraulic adjustment device). The damper module 2 is equipped with a first hydraulic chamber 21 and a second hydraulic chamber 22. The first hydraulic chamber 21 and the second hydraulic chamber 22 are filled with hydraulic fluid 200. The hydraulic adjustment module 3 controls the internal pressure in the first hydraulic chamber 21 and the internal pressure in the second hydraulic chamber 22. By controlling this internal pressure, the damper module 2 can absorb energy caused by earthquakes.

[0020] <Damper Module 2> The damper module 2 includes a cylinder 23, a piston 24, and a pair of piston rods 25a and 25b. The cylinder 23 is formed, for example, in a cylindrical shape. The cylinder 23 has an internal space 20 inside it. The internal space 20 is filled with hydraulic fluid 200 for operating the hydraulic damper 1.

[0021] The piston 24 is located inside the cylinder 23. The piston 24 is formed in a disc shape when viewed, for example, from a direction along the central axis of the cylinder 23. The piston 24 divides the internal space 20 into a first hydraulic chamber 21 and a second hydraulic chamber 22. The piston 24 reciprocates inside the cylinder 23.

[0022] <Hydraulic adjustment module 3> The hydraulic adjustment module 3 has several conduits for moving the hydraulic fluid 200 and several hydraulic circuit elements for mutually allowing and prohibiting the movement of the hydraulic fluid 200. Specifically, the hydraulic adjustment module 3 has a first open passage P1, a second open passage P2, and a mutual passage P3. Furthermore, the hydraulic adjustment module 3 has a first on / off control valve 31, a second on / off control valve 32, and a mutual on / off control valve 33. In addition, the hydraulic adjustment module 3 has an accumulator 38 (pressure release section) for adjusting the internal pressure of the damper module 2.

[0023] The first open passage P1 connects the first hydraulic chamber 21 and the accumulator 38. In other words, the first open passage P1 has the function of moving the hydraulic fluid 200 from the first hydraulic chamber 21 to the accumulator 38, and the function of moving the hydraulic fluid 200 from the accumulator 38 to the first hydraulic chamber 21. The second open passage P2 connects the second hydraulic chamber 22 and the accumulator 38. In other words, the second open passage P2 has the function of moving the hydraulic fluid 200 from the second hydraulic chamber 22 to the accumulator 38, and the function of moving the hydraulic fluid 200 from the accumulator 38 to the second hydraulic chamber 22.

[0024] In the example shown in Figure 2, the first open channel P1 includes a portion common to the second open channel P2. This common portion is referred to as the shared channel section Pc. The first end of the shared channel section Pc is connected to the accumulator 38. The second end of the shared channel section Pc is connected to the first branch channel section P1a and the second branch channel section P2a. The end of the first branch channel section P1a is connected to the first hydraulic chamber 21. The end of the second branch channel section P2a is connected to the second hydraulic chamber 22. This second end of the shared channel section Pc is referred to as the common connection point C1. In other words, the first open channel P1 includes the shared channel section Pc and the first branch channel section P1a. The second open channel P2 includes the shared channel section Pc and the second branch channel section P2a.

[0025] The first branch channel section P1a has its first end connected to a common connection point C1 and its second end connected to the first hydraulic chamber 21. The second end of the first branch channel section P1a is referred to as the first input / output section C3a of the hydraulic adjustment module 3. The second branch channel section P2a has its first end connected to a common connection point C1 and its second end connected to the second hydraulic chamber 22. The second end of the second branch channel section P2a is referred to as the second input / output section C3b of the hydraulic adjustment module 3.

[0026] The mutual flow path P3 has a first end connected to the first branch flow path section P1a and a second end connected to the second branch flow path section P2a. The point in the first branch flow path section P1a where the first end of the mutual flow path P3 is connected is referred to as the first branch connection point C2a. Similarly, the point in the second branch flow path section P2a where the second end of the mutual flow path P3 is connected is referred to as the second branch connection point C2b. In other words, the mutual flow path P3 has the function of moving hydraulic fluid 200 from the first branch flow path section P1a to the second branch flow path section P2a, and the function of moving hydraulic fluid 200 from the second branch flow path section P2a to the first branch flow path section P1a. The first branch flow path section P1a is connected to the first hydraulic chamber 21, and the second branch flow path section P2a is connected to the second hydraulic chamber 22. Therefore, the mutual flow path P3 has the function of moving the hydraulic fluid 200 from the first hydraulic chamber 21 to the second hydraulic chamber 22 in cooperation with the first branch flow path section P1a and the second branch flow path section P2a. Furthermore, the mutual flow path P3 has the function of moving the hydraulic fluid 200 from the second hydraulic chamber 22 to the first hydraulic chamber 21 in cooperation with the first branch flow path section P1a and the second branch flow path section P2a.

[0027] A first on / off control valve 31 is provided in the first branch channel section P1a of the first open channel P1. More specifically, the first on / off control valve 31 is provided between the common connection point C1 and the first branch connection point C2a. The first on / off control valve 31 switches between an open state, which allows the movement of hydraulic fluid 200 from the first hydraulic chamber 21 to the accumulator 38, and a closed state, which prohibits the movement of said hydraulic fluid 200. The first on / off control valve 31 may be electrically operated. Alternatively, the first on / off control valve 31 may operate in accordance with fluctuations in the hydraulic pressure of the hydraulic fluid 200.

[0028] A second on / off control valve 32 is provided in the second branch channel section P2a of the second open channel P2. More specifically, the second on / off control valve 32 is provided between the common connection point C1 and the second branch connection point C2b. The second on / off control valve 32 switches between an open state, which allows the movement of hydraulic fluid 200 from the second hydraulic chamber 22 to the accumulator 38, and a closed state, which prohibits the movement of said hydraulic fluid 200. The second on / off control valve 32 may be either electrically operated or passive.

[0029] The mutual opening / closing control valve 33 is provided in the mutual flow path P3. The mutual opening / closing control valve 33 switches between opening, which allows the movement of hydraulic fluid 200 from the first hydraulic chamber 21 to the second hydraulic chamber 22 and from the second hydraulic chamber 22 to the first hydraulic chamber 21, and closing, which prohibits the movement of hydraulic fluid 200. The mutual opening / closing control valve 33, like the first opening / closing control valve 31, may be electrically operated or may operate in accordance with fluctuations in the hydraulic pressure of the hydraulic fluid 200.

[0030] The accumulator 38 is connected to the first hydraulic chamber 21 via a first open passage P1. The accumulator 38 is also connected to the second hydraulic chamber 22 via a second open passage P2.

[0031] Although not shown in Figure 2, the hydraulic adjustment module 3 may include several additional elements, as shown in Figure 3.

[0032] The hydraulic adjustment module 3 has a first additional flow path P4 and a second additional flow path P5. The first additional flow path P4 is connected to the first branch flow path section P1a and the common flow path section Pc. Specifically, the first end of the first additional flow path P4 is connected between the first on / off control valve 31 and the first input / output section C3a in the first branch flow path section P1a. The second end of the first additional flow path P4 is connected between the common connection point C1 and the accumulator 38 in the common flow path section Pc. The second additional flow path P5 is connected to the second branch flow path section P2a and the common flow path section Pc. Specifically, the first end of the second additional flow path P5 is connected between the second on / off control valve 32 and the second input / output section C3b in the second branch flow path section P2a. The second end of the second additional flow path P5 is connected between the common connection point C1 and the accumulator 38 in the common flow path section Pc.

[0033] Furthermore, the hydraulic adjustment module 3 includes a first check valve 34, a first orifice 35, a second check valve 36, and a second orifice 37. The first check valve 34 is provided in the first additional passage P4. Specifically, the input side of the first check valve 34 is connected to the accumulator 38 via the common passage Pc. The output side of the first check valve 34 is connected to the first hydraulic chamber 21 via the first branch passage P1a. The first check valve 34 allows the movement of hydraulic fluid 200 from the accumulator 38 to the first hydraulic chamber 21, but prohibits the movement of hydraulic fluid 200 from the first hydraulic chamber 21 to the accumulator 38. The first orifice 35 is provided in the first additional passage P4 in parallel with the first check valve 34. The second check valve 36 is provided in the second additional passage P5. Specifically, the input side of the second check valve 36 is connected to the accumulator 38 via the shared flow path Pc. The output side of the second check valve 36 is connected to the second hydraulic chamber 22 via the second branch flow path P2a. The second check valve 36 allows the movement of hydraulic fluid 200 from the accumulator 38 to the second hydraulic chamber 22, but prohibits the movement of hydraulic fluid 200 from the second hydraulic chamber 22 to the accumulator 38. The second orifice 37 is provided in the second additional flow path P5 so as to be in parallel with the second check valve 36.

[0034] The hydraulic adjustment module 3 can switch between the first hydraulic circuit configuration H1, the second hydraulic circuit configuration H2, and the third hydraulic circuit configuration H3. In the first hydraulic circuit configuration H1 (see Figure 4(b), etc.), the mutual on / off control valve 33 is closed, the first on / off control valve 31 is closed, and the second on / off control valve 32 is closed. In the second hydraulic circuit configuration H2 (see Figure 4(h), etc.), the mutual on / off control valve 33 is open, the first on / off control valve 31 is closed, and the second on / off control valve 32 is closed. In the third hydraulic circuit configuration H3 (see Figure 5(b), etc.), the mutual on / off control valve 33 is closed, and one of the first on / off control valve 31 and the second on / off control valve 32 is open, while the other is closed.

[0035] The operation process of the hydraulic damper 1 will be explained with reference to Figures 4, 5, and 6. In the following explanation, the capacity of the accumulator 38 is assumed to be sufficiently large, and the initial pressure (prestress) of the accumulator 38 is assumed to be negligibly small compared to the pressure generated in the first hydraulic chamber 21 or the second hydraulic chamber 22 due to vibrations of the building 100.

[0036] <First state> Figure 4(a) shows the building structure 110 in the first state ST1, when no earthquake or other seismic activity has occurred and the building 100 is not deformed. For example, in the first state ST1, the brace connection 103c is at position La1. In the following explanation, deformation occurs in the building structure 110 when an earthquake acts on the building 100. In the following explanation, the deformation of the building structure 110 is defined as relative displacement δ (see Figure 4(d)). Relative displacement δ is the displacement of the structural connection 110c with respect to the structural connection 110d.

[0037] When building 100 is in the first state ST1, which is not deformed, the hydraulic damper 1 is in the first hydraulic circuit configuration H1, as shown in Figure 4(b). When the first hydraulic circuit configuration H1 is in place, the state of each control valve is as follows. In Figure 4(b), a closed control valve is indicated by filling the symbol representing the control valve in black. An open control valve is indicated by filling the symbol representing the control valve in white. • First on / off control valve 31: Closed • Second control valve 32: Closed • Mutual opening / closing control valve 33: Closed

[0038] When in the first state ST1, the piston 24 may be located approximately in the center of the cylinder 23. When in the first state ST1, the pressure in the first hydraulic chamber 21 is approximately the same as the pressure in the second hydraulic chamber 22. In Figure 4(b), the degree of pressure in the first hydraulic chamber 21 and the second hydraulic chamber 22 is illustrated by the density of the hatching. A relatively high pressure state is indicated by dark hatching. A relatively low pressure state is indicated by light hatching. When in the first state ST1, there is no significant difference in the pressures of the first hydraulic chamber 21 and the second hydraulic chamber 22, so the density of the hatching in the first hydraulic chamber 21 is the same as the density of the hatching in the second hydraulic chamber 22. Also, when in the first state ST1, the pressure in the first hydraulic chamber 21 is the same as the pressure in the accumulator 38, and the pressure in the second hydraulic chamber 22 is the same as the pressure in the accumulator 38.

[0039] Here, we will explain the mechanical model K120 of the hydraulic damper 1 shown in Figure 4(c), etc. Figure 4(c) shows the mechanical model K120 in which an elastic element E103a, which simulates the stiffness of the brace 103a, an elastic element E1, which simulates the stiffness of the hydraulic damper 1, and a damping element D1, which simulates the damping coefficient C of the hydraulic damper 1, are connected in series in this order. In the mechanical model K120 shown in Figure 4(f), etc., used in the following explanation, the elastic elements E103a and E1 are shown as a single composite elastic element E120. The composite elastic element E120 has stiffness equivalent to the stiffness of the series-connected elastic elements E103a and E1.

[0040] The mechanical model K120 of the hydraulic damper 1 can be represented as a Maxwell model in which a composite elastic element E120 and a damping element D1 are connected in series. This mechanical model K120 takes into account the stiffness of the brace 103a. The damping element D1 is controlled by the opening and closing of the mutual opening / closing control valve 33, the first opening / closing control valve 31, or the second opening / closing control valve 32, thereby controlling the damping coefficient (C max ) or damping coefficient (C min) switches to. That is, the dynamic model K120 shown as the Maxwell model of this embodiment has nonlinearity in the damping element D1. Here, when the mutual opening / closing control valve 33, the first opening / closing control valve 31 and the second opening / closing control valve 32 are all closed, the damping element D1 has a damping coefficient (C max ) When the mutual opening / closing control valve 33 is open, the damping element D1 has a damping coefficient (C min ) is the case. Note that in the following explanation, the damping coefficient (C) is used. max ) is infinite, damping coefficient (C min Assume that ) is zero.

[0041] Figure 4(c) shows the mechanical model K120 of the building structure 110 in the first state ST1. In the first state ST1, the relative displacement (δ) is zero. In the first state ST1, the spring length Ld1 of the composite elastic element E120 is its natural length. In other words, since the relative displacement (δ) is zero, no elastic force is generated in the composite elastic element E120. Also, since the horizontal velocity of the structural connection part 110c is zero, no damping force is generated in the damping element D1.

[0042] Here, we focus on the relationship between the relative displacement (δ) at the structural connection 110c and the internal load generated in the seismic damping structure 120. Figures 6(a), 6(b), and 6(c) show the relationship between the horizontal relative displacement (δ) of the structural connection 11c with respect to the structural connection 110d and the internal load F120 generated in the seismic damping structure 120. For example, the horizontal axis in Figure 6(a), etc., represents the relative displacement (δ). The vertical axis in Figure 6(a), etc., corresponds to the internal load F120 generated in the composite elastic element E120 of the mechanical model K120 shown in Figure 4(c), etc. In the first state ST1, the mutual opening / closing control valve 33, the first opening / closing control valve 31, and the second opening / closing control valve 32 are all closed, so the damping element D1 has a damping coefficient (C max) is infinite. In other words, the damping element D1 can be considered a rigid body. Under this assumption, the internal load F120 can be considered the product of the relative displacement (δ) and the stiffness (K) of the composite elastic element E120. In the case of the damper module 2 shown in Figure 4(b), the internal load F120 is the product of the differential pressure between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 and the cross-sectional area of ​​the piston. As described above, in the first state ST1, the relative displacement (δ) is zero. This state (first state ST1: δ=0) is indicated by point GP1 shown in Figure 6(a).

[0043] <Second state> Figure 4(d) shows the second state ST2, which occurs just before the direction of the displacement reverses after the building structure 110 shown in Figure 4(a) has deformed due to an earthquake or the like, causing a relative displacement (δ) at the structural connection part 110c. In the second state ST2, the position of the structural connection part 110c relative to the structural connection part 110d can be expressed as the relative displacement (δ). On the other hand, since the mutual opening / closing control valve 33 of the hydraulic damper 1 is closed, there is no movement of hydraulic fluid between the first hydraulic chamber 21 and the second hydraulic chamber 22. In other words, the piston 24 can be considered to be substantially stationary. Consequently, the brace connection part 103c also maintains its position L1a. In this case, the effect of the relative displacement (δ) extends to the brace 103a and the brace 103b. Specifically, a compressive force acts on the brace 103a and a tensile force acts on the brace 103b. To respond to this compressive force, the pressure in the first hydraulic chamber 21 increases. Furthermore, during the transition from the first state ST1 to the second state ST2, the structural connecting portion 110c continues to move in one direction and does not move in the opposite direction.

[0044] Until the building structure part 110 is deformed from the first state ST1 to the second state ST2, as shown in Fig. 4(e), the hydraulic damper 1 continues to maintain the first hydraulic circuit configuration H1. More specifically, while the moving direction of the housing connecting part 110c continues to move in one direction, the hydraulic damper 1 continues to maintain the first hydraulic circuit configuration H1. That is, until the moving direction of the housing connecting part 110c reverses, the hydraulic damper 1 maintains the first hydraulic circuit configuration H1. At this time, in the first hydraulic circuit configuration H1, all control valves are closed, and since the force acting through the brace 103a, the pressure in the first hydraulic chamber 21 continues to rise. On the other hand, the pressure in the second hydraulic chamber 22 is maintained. As a result, the pressure in the first hydraulic chamber 21 becomes relatively higher than the pressure in the second hydraulic chamber 22. In Fig. 4(e), in order to show that the pressure in the first hydraulic chamber 21 is higher than the pressure in the second hydraulic chamber 22, the hatch density in the first hydraulic chamber 21 is shown darker than the hatch density in the second hydraulic chamber 22.

[0045] As described above, while the housing connecting part 110c continues to move in one direction, the hydraulic damper 1 maintains the first hydraulic circuit configuration H1. Maintaining the first hydraulic circuit configuration H1 may be conditional on the movement of the housing connecting part 110c or may follow other conditions. For example, maintaining the first hydraulic circuit configuration H1 may be conditional on the pressure in the first hydraulic chamber 21 rising. That is, while the moving direction of the housing connecting part 110c continues to move in one direction, the pressure in the first hydraulic chamber 21 continues to increase. Therefore, when the pressure in the first hydraulic chamber 21 is increasing, the hydraulic damper 1 may maintain the first hydraulic circuit configuration H1. In other words, until the pressure in the first hydraulic chamber 21 begins to decrease, the first hydraulic circuit configuration H1 may be maintained.

[0046] Fig. 4(f) shows the mechanical model K120 of the building structure part 110 when it is in the second state ST2. In the second state ST2, a relative displacement (δ) occurs between the housing connecting parts 110c and 110d. In the second state ST2, since all control valves are closed, the state of the damping element D1 is the damping coefficient (C max ) as described above. The damping coefficient (C maxSince we assume that the magnitude is infinite, the damping element D1 can be considered as a rigid body. As a result, the hydraulic damper 1 can be simulated as a model containing only the composite elastic element E120.

[0047] Here, we again focus on the relationship between the relative displacement (δ) at the structural connection section 110c and the internal load generated in the seismic damping structure section 120. In Figure 6(a), the transition from the first state ST1 to the second state ST2 is shown by the line segment GL2. The second state ST2 is shown by point GP2. In the second state ST2, the relative displacement (δ) at the structural connection section 110c is the difference between the horizontal displacement generated in the structural connection section 110c and the horizontal displacement generated in the structural connection section 110c. As a result, the internal load F120 generated in the seismic damping structure section 120 is shown as the product of the relative displacement (δ) and the stiffness (K) of the composite elastic element E120.

[0048] <Third state> Figure 4(g) shows the building structure 110 in the third state ST3. More specifically, Figure 4(g) shows the state immediately before transitioning to the next fourth state ST4 during the period in the third state ST3. The position of the structural connection part 110c in the third state ST3 is the same as the position in the second state ST2 shown in Figure 4(d). The position of the structural connection part 110c shown in Figure 4(g) can also be said to indicate, for example, the turning point of the structural connection part 110c.

[0049] When the direction of movement of the structural connection part 110c is reversed, the hydraulic damper 1 switches from the first hydraulic circuit configuration H1 to the second hydraulic circuit configuration H2, as shown in Figure 4(h). When the second hydraulic circuit configuration H2 is in place, the state of each control valve is as follows. • Mutual opening / closing control valve 33: Open • First on / off control valve 31: Closed • Second control valve 32: Closed

[0050] In other words, the mutual opening / closing control valve 33 is switched from closed to open. The first opening / closing control valve 31 and the second opening / closing control valve 32 remain closed. As a result, the hydraulic fluid 200 moves from the first hydraulic chamber 21 to the second hydraulic chamber 22. Consequently, the differential pressure between the first hydraulic chamber 21 and the second hydraulic chamber 22 is eliminated. At this time, the pressure in the second hydraulic chamber 22 increases, and as a result, the pressure in the second hydraulic chamber 22 becomes higher than the pressure in the accumulator 38. When changing from the second state ST2 to the third state ST3, the position of the frame connection part 110c is maintained, and the position of the brace connection part 103c moves by the same distance as the relative displacement (δ), so it moves from position L1a to position La2. As a result, the internal load F120 becomes zero. While the hydraulic fluid 200 moves from the first hydraulic chamber 21 to the second hydraulic chamber 22, the strain energy stored in the composite elastic element E120 is consumed as heat.

[0051] The switching operation from the first hydraulic circuit configuration H1 to the second hydraulic circuit configuration H2 may be performed based on the pressure in the first hydraulic chamber 21. That is, the switch may be performed from the first hydraulic circuit configuration H1 to the second hydraulic circuit configuration H2 when the pressure in the first hydraulic chamber 21 begins to decrease.

[0052] Figure 4(i) shows the mechanical model K120 of the building structure 110 in the third state ST3. In the third state ST3, the relative displacement (δ) of the structural connection part 110c is the same as in the second state ST2. On the other hand, in the third state ST3, the differential pressure between the first hydraulic chamber 21 and the second hydraulic chamber 22 is eliminated when the mutual opening / closing control valve 33 is opened. This phenomenon can be represented by the elimination of the compression of the composite elastic element E120 and its return to its natural length. Figure 4(f) shows the compressed composite elastic element E120 with spring length Ld2. Figure 4(i) shows the composite elastic element E120 returned to its natural length with spring length Ld1.

[0053] Here, we again focus on the relationship between the relative displacement (δ) of the structural connection part 110c and the internal load F120 generated in the seismic damping structure part 120. In Figure 6(b), the transition from the second state ST2 to the third state ST3 is shown by the line segment GL3. The third state ST3 is shown by point GP3. In the third state ST3, the relative displacement (δ) of the structural connection part 110c does not change from the relative displacement (δ) of the structural connection part 110c in the second state ST2 because the transition is short. On the other hand, the internal load F120 generated in the seismic damping structure part 120 changes from a predetermined value to zero. Therefore, the transition from the second state ST2 to the third state ST3 is shown in Figure 6(c) as the line segment GL3 parallel to the Y axis. Point GP3, which indicates the third state ST3, is shown as a point on the X axis.

[0054] <Fourth state> Figure 5(a) shows the fourth state ST4 of the building structure 110 when the hydraulic damper 1 is switched from the second hydraulic circuit configuration H2 to the third hydraulic circuit configuration H3. In the fourth state ST4, the hydraulic fluid 200 is moved from the first hydraulic chamber 21 to the accumulator 38. As a result, the pressure in the first hydraulic chamber 21 decreases, and the pressure in the second hydraulic chamber 22 becomes higher than the pressure in the first hydraulic chamber 21. In this state, an internal load F120 based on the differential pressure acts on the piston 24 from the second hydraulic chamber 22 toward the first hydraulic chamber 21. Specifically, in the state where the change from the third state ST3 to the fourth state ST4 begins (state GP3 in Figure 6(c)), the internal load F120 is zero. An internal load F120 acts on the piston 24 in the opposite direction to the movement of the structural connection portion 110c due to the differential pressure between the first hydraulic chamber 21 and the second hydraulic chamber 22, which increases as the hydraulic fluid 200 in the first hydraulic chamber 21 moves to the accumulator 38. In this case, the piston 24 moves a distance corresponding to the internal load F120. That is, the hydraulic damper 1 extends by a distance corresponding to the internal load F120. As a result, the brace connection portion 103c moves from position La2 to position La3. Consequently, strain energy corresponding to the internal load F120 is stored in the composite elastic element E120. The time required for this operation is short compared to the vibration of the building, and the movement of the piston 24 due to building deformation can be ignored.

[0055] When in the fourth state ST4, as shown in Figure 5(b), the hydraulic damper 1 switches from the second hydraulic circuit configuration H2 to the third hydraulic circuit configuration H3. When in the third hydraulic circuit configuration H3, the state of each control valve is as follows. • First control valve 31: Open • Second control valve 32: Closed • Mutual opening / closing control valve 33: Closed

[0056] Specifically, first, the mutual control valve 33 switches from open to closed. This action prevents the movement of hydraulic fluid 200 from the first hydraulic chamber 21 to the second hydraulic chamber 22. Subsequently, the first control valve 31 switches from closed to open, connecting the first hydraulic chamber 21, which was the high-pressure side in the second state ST2, with the accumulator 38. Just before the first control valve 31 switches from closed to open, the pressure in the first hydraulic chamber 21 is higher than the pressure in the accumulator 38. When the first control valve 31 switches from closed to open, this action causes the hydraulic fluid 200 to move from the first hydraulic chamber 21 to the accumulator 38. Figure 5(b) illustrates the situation when the first control valve 31 is open. As a result, the pressure in the first hydraulic chamber 21 becomes equal to the pressure in the accumulator 38. This action is referred to as releasing the pressure in the first hydraulic chamber 21. Then, when the pressure in the first hydraulic chamber 21 becomes equal to the pressure in the accumulator 38, the first on / off control valve 31 switches from open to closed. This switch changes the configuration from the third hydraulic circuit configuration H3 to the first hydraulic circuit configuration H1.

[0057] Meanwhile, the second control valve 32 maintains its closed position. Under this operation, the hydraulic fluid 200 in the second hydraulic chamber 22 cannot move to either the first hydraulic chamber 21 or the accumulator 38. In other words, the pressure in the second hydraulic chamber 22 is maintained. Consequently, just before the first control valve 31 switches from closed to open, the pressure in the first hydraulic chamber 21 was equal to the pressure in the second hydraulic chamber 22. Then, when the first control valve 31 switches from closed to open, only the pressure in the first hydraulic chamber 21 decreases. As a result, a pressure difference is created between the first hydraulic chamber 21 and the second hydraulic chamber 22. Specifically, the pressure in the second hydraulic chamber 22 is greater than the pressure in the first hydraulic chamber 21. This pressure difference causes an internal load F120 to act on the piston 24 from the second hydraulic chamber 22 towards the first hydraulic chamber 21.

[0058] Figure 5(c) shows the mechanical model K120 of the building structure 110 when it is in the fourth state ST4. As described above, the switch from the third state ST3 to the fourth state ST4 results in a change in the state in which the pressure in the second hydraulic chamber 22 becomes greater than the pressure in the first hydraulic chamber 21, and accordingly the piston 24 receives an internal load F120 based on the differential pressure which is directed to the right in the plane of the paper. In the mechanical model K120, this internal load F120 based on the differential pressure can be shown as the elongation of the composite elastic element E120 which is directed to the right in the plane of the paper. As a result, the composite elastic element E120 elongates from spring length Ld1 to spring length Ld4.

[0059] Here, we again focus on the relationship between the relative displacement (δ) of the structural connection section 110c and the internal load F120 generated in the seismic damping structure section 120. In Figure 6(c), the transition from the third state ST3 to the fourth state ST4 is shown by the line segment GL4. The fourth state ST4 is shown by point GP4. Since the movement in the fourth state ST4 is extremely short, the relative displacement (δ) of the structural connection section 110c does not change from the relative displacement (δ) of the structural connection section 110c in the third state ST3. On the other hand, the internal load F120 generated in the seismic damping structure section 120 changes from zero to a predetermined value. This predetermined value is the internal load F120 based on differential pressure. Since this internal load F120 based on differential pressure stretches the composite elastic element E120, it is shown with a negative sign in Figure 6(c).

[0060] <5th state> As shown in Figure 5(c), the state immediately before switching from the fourth state ST4 to the fifth state ST5 is such that the composite elastic element E120 has already stretched by a predetermined length in the direction of the internal load F120. From this state, the piston 24 is subjected to the relative displacement (δ) of the frame connecting portion 110c, which is oriented to the left in the plane of the paper.

[0061] Figure 5(f) is a mechanical model K120 showing how the piston 24 moves to the left side of the paper due to the relative displacement (δ) of the structural connection part 110c, starting from a state of displacement (Ld4) due to the internal load F120. The increase in the load acting on the composite elastic element E120 is shown by the fact that the composite elastic element E120 stretches further to the left of the paper due to the relative displacement (δ) of the structural connection part 110c, starting from a state where the spring length Ld4 is longer than the natural length Ld1 due to the internal load F120.

[0062] As shown in Figure 5(e), when the piston 24 is moving with all three control valves closed—the first on / off control valve 31, the second on / off control valve 32, and the mutual on / off control valve 33—the hydraulic damper 1 again exhibits spring-like behavior. In other words, the pressure in the second hydraulic chamber 22 increases further in response to this movement.

[0063] As shown in Figure 5(f), the movement of the piston 24 is indicated by the change in the relative displacement (δ) of the frame connection portion 110c. Furthermore, the load acting on the composite elastic element E120 also increases further. This is indicated by the further extension of the composite elastic element E120 to the left in the plane of the paper. As a result, the composite elastic element E120 extends from spring length Ld4 to spring length Ld5.

[0064] Here again, we focus on the relationship between the relative displacement (δ) of the structural connection part 110c and the internal load F120 generated in the seismic damping structure part 120. In Figure 6(c), the transition from the fourth state ST4 to the fifth state ST5 is shown by the line segment GL5. As described above, in the fifth state ST5, the structural connection part 110c moves to the left of the plane of the paper, so the line segment GL5 extends in Figure 6(c) such that the value of the X axis gradually decreases. Furthermore, in the fifth state ST5, the composite elastic element E120 extends further to the left of the plane of the paper (see Figure 5(f)), so the absolute value of the internal load F120 also gradually increases due to this extension.

[0065] Of particular note is that the starting point of the fifth state ST5 has a predetermined pressure. From this state, the piston 24 begins to move to the left in the plane of the paper, and the endpoint of the fifth state ST5, when the movement is completed, has a higher pressure than the pressure in the first state ST1. This is thought to be due to the internal load F120 caused by the differential pressure that occurred when transitioning from the third state ST3 to the fourth state ST4.

[0066] [Method for controlling hydraulic dampers] Referring to Figure 7, the method for controlling the hydraulic damper 1 in this embodiment will be described. Here, the method for controlling the hydraulic damper 1 can be realized by two operating modes.

[0067] In the first embodiment, the opening and closing control of the first on / off control valve 31, the second on / off control valve 32, and the mutual on / off control valve 33 is performed by the functions of the hydraulic circuit elements constituting the hydraulic adjustment module 3. In the first embodiment, sensors for measuring the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22, and a controller that generates control signals for each control valve using data obtained from the sensors are not required. In the second embodiment, the hydraulic damper 1 is equipped with sensors and a controller, and the opening and closing control of the first on / off control valve 31, the second on / off control valve 32, and the mutual on / off control valve 33 is performed by the control signals output by the controller. A specific example of the hydraulic damper 1 operating in the first embodiment will be described later as the first embodiment. A specific example of the hydraulic damper 1 operating in the second embodiment will be described later as the second embodiment.

[0068] The following describes a method for controlling a hydraulic damper, using a hydraulic damper 1 operating in the first mode as an example. In the following description, the operation of the hydraulic damper 1 is referred to as "step S". The operation of the hydraulic damper 1 described as "step S" is an active operation that occurs due to a preset function of the hydraulic damper 1. Furthermore, the event that triggers the operation of the hydraulic damper 1 is referred to as "event N".

[0069] First, in the first state ST1 where no earthquake has occurred (see Figures 4(a), 4(b), and 4(c)), the hydraulic damper 1 enters the first hydraulic circuit configuration H1 (step S1). Step S1 includes closing the first on / off control valve 31 (step S11), closing the second on / off control valve 32 (step S12), and closing the mutual on / off control valve 33 (step S13). These steps S11, S12, and S13 may be performed in any order.

[0070] Next, let's assume an earthquake occurs (event N1). Due to the earthquake, the piston 24 begins to move toward the first hydraulic chamber 21, resulting in a second state ST2 (event N2: see Figures 4(d), 4(e), and 4(f)). While in the second state ST2, the hydraulic damper 1 maintains the first hydraulic circuit configuration H1 (step S2).

[0071] Next, the direction of the external load reverses (event N3). As a result, the direction of movement of the piston 24 reverses (event N4). The state in which the direction of movement of the piston 24 is reversed is the third state ST3 (see Figures 4(g), 4(h), and 4(i)). When the third state ST3 is reached, the hydraulic damper 1 switches from the first hydraulic circuit configuration H1 to the second hydraulic circuit configuration H2 (step S3). Step S3 includes maintaining the closure of the first on / off control valve 31 (step S31), maintaining the closure of the second on / off control valve 32 (step S32), and switching the mutual on / off control valve 33 from closed to open (step S33). These steps S31, S32, and S33 may be performed in any order.

[0072] Next, the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 balance out (event N5). When the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 balance out, the hydraulic damper 1 switches from the second hydraulic circuit configuration H2 to the third hydraulic circuit configuration H3 (step S4). Step S4 includes switching the mutual on / off control valve 33 from open to closed (step S41), switching the first on / off control valve 31 from closed to open (step S42), and maintaining the closed state of the second on / off control valve 32 (step S43). Step S41 is performed before step 42. Step S43 is the maintenance of the closed state, so the order of steps S41 and S42 does not matter.

[0073] The pressure in the first hydraulic chamber 21 is released. The state in which the pressure in the first hydraulic chamber 21 is released is the fourth state ST4 (see Figures 5(a), 5(b), and 5(c)). The first on / off control valve 31 of the hydraulic damper 1 switches from closed to open (step S42). As a result, the pressure in the first hydraulic chamber 21 decreases, and the piston 24 moves from the second hydraulic chamber 22 towards the first hydraulic chamber 21 due to the internal load F120 based on the differential pressure between it and the second hydraulic chamber 22 (step N6).

[0074] When the pressure in the first hydraulic chamber 21 is in equilibrium with the pressure in the accumulator 38 (event N7), the hydraulic damper 1 switches from the third hydraulic circuit configuration H3 to the first hydraulic circuit configuration H1 (step S5). Step S5 includes switching the first on / off control valve 31 from open to closed (step S51), maintaining the closed position of the second on / off control valve 32 (step S52), and maintaining the closed position of the mutual on / off control valve 33 (step S53). These steps S51, S52, and S53 may be performed in any order.

[0075] In the fifth state ST5 (event N8: see Figures 5(d), 5(e), and 5(f)), when all of the first on / off control valve 31, the second on / off control valve 32, and the mutual on / off control valve 33 are closed, the hydraulic damper 1 becomes the first hydraulic circuit configuration H1. Then, steps S2 to S5 are executed again. Note that the position Lb1 shown by the dashed line in Figure 5(d) is the position of the structural connection part 110c when the building 100 is in the first state ST1, which is not deformed.

[0076] [Mechanism of Action and Effects] The embodiments described in detail above relate to a hydraulic damper for seismic control used to reduce building sway caused by vibrational external forces F100 such as earthquakes and wind, a control method for a hydraulic damper on / off control valve that controls the on / off control valve, and a hydraulic damper used in the method.

[0077] Seismic damping technologies applicable to structures are being investigated. For example, one seismic damping technology involves using oil dampers attached to the structure to absorb energy imparted to it by earthquakes and other seismic events. Generally, the damping coefficient of an oil damper is constant. As a result, there is a limit to the amount of energy that can be absorbed, due to constraints not only on the rigidity of the damping device itself, but also on the rigidity of the connecting members that attach the damping device to the structure, and the rigidity caused by the deformation of the surrounding frame in which the damping device is installed.

[0078] Japanese Patent Publication No. 2002-013310 discloses a variable damping device for seismic isolation structures, and Japanese Patent Publication No. 2006-153068 discloses a hydraulic damper with a damping coefficient switching mechanism. These devices have an on / off control valve provided in the flow path of the oil damper. By controlling the opening of the on / off control valve to either fully open or fully closed, the amount of energy absorbed can be improved. This control makes it possible to maximize the amount of energy absorbed under the constraints caused by the rigidity mentioned above.

[0079] Japanese Patent Publication No. 2014-163502 discloses a control method for a hydraulic damper on / off control valve. The apparatus to which this control method is applied further includes a hydraulic tank in addition to the hydraulic damper and on / off control valve. With this hydraulic tank and on / off control valve, energy supplied to the structure can be regenerated, and the regenerated energy can be repurposed for vibration damping. As a result, the amount of energy absorbed is further improved.

[0080] The device disclosed in Japanese Patent Publication No. 2014-163502 includes a hydraulic tank and three on / off control valves as components for energy regeneration. Consequently, the structure of the additional components to the hydraulic damper becomes complex.

[0081] Therefore, this embodiment describes a hydraulic damper and a control method for the hydraulic damper that exceed the theoretically maximum energy absorption amount of the Maxwell model by utilizing an accumulator and a hydraulic chamber without adding a hydraulic tank.

[0082] The hydraulic damper 1 comprises a cylinder 23 having an internal space 20 filled with hydraulic fluid, a piston 24 positioned inside the cylinder 23 that divides the internal space 20 into a first hydraulic chamber 21 and a second hydraulic chamber 22 and moves back and forth inside the cylinder 23, and hydraulic adjustment modules 3 connected to the first hydraulic chamber 21 and the second hydraulic chamber 22, respectively. The hydraulic adjustment module 3 is connected to the first hydraulic chamber 21 via a first open passage P1 and to the second hydraulic chamber 22 via a second open passage P2, and includes an accumulator 38 for releasing the pressure in the first hydraulic chamber 21 and the second hydraulic chamber 22, with one end connected to the first hydraulic chamber 21 and the other end connected to the second The system includes: a mutual on / off control valve 33 provided in a mutual flow path P3 connected to the hydraulic chamber 22, which switches between opening to allow the movement of hydraulic fluid from the first hydraulic chamber 21 to the second hydraulic chamber 22 and from the second hydraulic chamber 22 to the first hydraulic chamber 21, and closing to prohibit the movement of hydraulic fluid; a first on / off control valve 31 provided in the first open flow path P1, which switches between opening to allow the movement of hydraulic fluid from the first hydraulic chamber 21 to the accumulator 38, and closing to prohibit the movement of hydraulic fluid; and a second on / off control valve 32 provided in the second open flow path P2, which switches between opening to allow the movement of hydraulic fluid from the second hydraulic chamber 22 to the accumulator 38, and closing to prohibit the movement of hydraulic fluid.

[0083] The hydraulic adjustment module 3 of the hydraulic damper 1 includes a mutual on / off control valve 33, a first on / off control valve 31, and a second on / off control valve 32. In this configuration, for example, when the hydraulic pressure in the high-pressure side first hydraulic chamber 21 begins to decrease, the mutual on / off control valve 33 can be opened. This moves the hydraulic fluid from the high-pressure side first hydraulic chamber 21 to the low-pressure side second hydraulic chamber 22, thereby balancing the hydraulic pressure between the pair of hydraulic chambers, the first and second hydraulic chambers. Furthermore, since the hydraulic adjustment module 3 has a first on / off control valve 31, when the differential pressure between the first hydraulic chamber 21 and the second hydraulic chamber 22 is eliminated, the first on / off control valve 31 can be switched from closed to open, moving the hydraulic fluid from the high-pressure side first hydraulic chamber 21 to the accumulator 38. This creates a differential pressure between the first hydraulic chamber 21 and the second hydraulic chamber 22. As a result, the load of the hydraulic damper 1 can be offset, increasing the amount of energy absorbed.

[0084] Furthermore, since the hydraulic damper 1 does not have an auxiliary hydraulic tank, the configuration of the hydraulic circuit can be simplified. As a result, the energy absorption capacity can be improved while simplifying the structure of the hydraulic damper. In addition, since an accumulator 38, which is provided in general hydraulic dampers, can be used as the pressure release section, it is possible to suppress the increase in size compared to general hydraulic dampers and also suppress the increase in cost.

[0085] The hydraulic adjustment module 3 switches between a first hydraulic circuit configuration in which the mutual control valve 33 is closed, the first control valve 31 is closed, and the second control valve 32 is closed; a second hydraulic circuit configuration in which the mutual control valve 33 is open, the first control valve 31 is closed, and the second control valve 32 is closed; and a third hydraulic circuit configuration in which the mutual control valve 33 is closed, and one of the first control valve 31 and the second control valve 32 is open while the other is closed. This configuration allows for an appropriate improvement in energy absorption.

[0086] The hydraulic adjustment module 3 switches between the first hydraulic circuit configuration, the second hydraulic circuit configuration, and the third hydraulic circuit configuration in that order. This configuration allows for an appropriate improvement in energy absorption.

[0087] The hydraulic adjustment module 3 switches between the first hydraulic circuit configuration, the second hydraulic circuit configuration, and the third hydraulic circuit configuration based on the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22. This allows the first hydraulic circuit configuration, the second hydraulic circuit configuration, and the third hydraulic circuit configuration to be switched based on the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22, without having to rely on, for example, the direction of piston movement.

[0088] The hydraulic adjustment module 3 configures itself as a first hydraulic circuit when the pressure in the first hydraulic chamber 21 increases in response to the movement of the piston 24. When the direction of movement of the piston 24 reverses, it switches from the first hydraulic circuit configuration to a second hydraulic circuit configuration in which the mutual on / off control valve 33 is open and the first on / off control valve 31 and the second on / off control valve 32 are closed. When the differential pressure between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 falls below a threshold, it configures itself as a third hydraulic circuit configuration in which the first on / off control valve 31 is open and the second on / off control valve 32 is closed. This configuration allows for an appropriate improvement in energy absorption. Specifically, when the differential pressure between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 falls below a threshold, the third hydraulic circuit configuration, in which the first on / off control valve 31 is open and the second on / off control valve 32 is closed, can create a differential pressure between the first hydraulic chamber 21 and the second hydraulic chamber 22. This differential pressure acts in the opposite direction to the direction of movement of the piston 24. As a result, the amount of energy absorbed can be increased by offsetting the load.

[0089] In other words, when the building deforms and the pressure in the first hydraulic chamber 21 increases, the springs of the hydraulic damper 1 and braces 103a and 103b store the building's vibration energy. At the moment when the vibration of the building 100 reverses (i.e., when the pressure in the first hydraulic chamber 21 begins to decrease), the hydraulic fluid is rapidly moved to the second hydraulic chamber 22 to equalize the pressures in the first and second hydraulic chambers 21 and 22. Subsequently, the first on / off control valve 31 is opened to move the hydraulic fluid from the first hydraulic chamber 21 to the accumulator 38, rapidly creating a differential pressure between the first and second hydraulic chambers 21 and 22. This offsets the load on the hydraulic damper 1, increasing the amount of energy absorbed.

[0090] A method for controlling a hydraulic damper includes: a first step of prohibiting the outflow of hydraulic fluid from the first hydraulic chamber 21 and the second hydraulic chamber 22 when the pressure in the first hydraulic chamber 21 increases in response to the movement of the piston 24; a second step of allowing the movement of hydraulic fluid from the first hydraulic chamber 21 to the second hydraulic chamber 22 when the direction of movement of the piston 24 reverses; and a third step of prohibiting the movement of hydraulic fluid from the first hydraulic chamber 21 to the second hydraulic chamber 22 and releasing the pressure in the first hydraulic chamber 21 when the differential pressure between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 falls below a threshold. This method for controlling a hydraulic damper, like the hydraulic damper 1, can improve energy absorption while simplifying the structure of the hydraulic damper.

[0091] <First Example> Figure 8 is a hydraulic circuit diagram of the hydraulic adjustment module 3A provided in the hydraulic damper 1A according to the first embodiment. The hydraulic adjustment module 3A has, as its main elements, a first on-off valve 51 and a second on-off valve 52. The first on-off valve 51 functions as a mutual on-off control valve 33. As an element for switching the operation of the first on-off valve 51, the hydraulic adjustment module 3A has a pilot operated valve 54. In addition, the flow path connecting these elements is provided with a buffer 62, orifices 60, 63, 64, a variable orifice 65, check valves 66, 67, and a relief valve 68. The second on-off valve 52 functions as either the first on-off control valve 31 or the second on-off control valve 32 depending on the position of the directional control valve 55. The position of the directional control valve 55 follows the relationship between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22. Furthermore, the hydraulic adjustment module 3A has a first switching valve 53. The first switching valve 53 functions as an element that releases the pressure accumulated in the buffer 62. The hydraulic adjustment module 3A also includes a relief valve 39 for releasing excessive pressure in the first hydraulic chamber 21 and a relief valve 40 for releasing excessive pressure in the second hydraulic chamber 22.

[0092] The hydraulic adjustment module 3A further includes a directional control valve 55. Depending on the relationship between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22, the directional control valve 55 connects one of the first hydraulic chamber 21 and the second hydraulic chamber 22 to the first on-off valve 51 and the other of the first hydraulic chamber 21 and the second hydraulic chamber 22 to the second on-off valve 52.

[0093] <First Hydraulic Circuit Configuration> The first hydraulic circuit configuration H1 is in a state where the first on-off valve 51 is closed and the second on-off valve 52 is also closed. Assume that the pressure in the first hydraulic chamber 21 is higher than the pressure in the second hydraulic chamber 22. In this state, the pressure acting on the right side 55b of the directional control valve 55 is greater than the pressure acting on the left side 55a, so the first hydraulic chamber 21 is connected to the front surface 51a of the first on-off valve 51 and the second hydraulic chamber 22 is connected to the front surface 52a of the second on-off valve 52. When the pressure in the first hydraulic chamber 21 is high and the pressure in the first hydraulic chamber 21 is rising, the pressure acting on the left side 54a of the pilot-operated valve 54 is less than the sum of the pressure acting on the right side 54b of the pilot-operated valve 54 and the spring pressure, so the pilot-operated valve 54 is closed. At this time, the first on-off valve 51 is in a closed state. Furthermore, the first on-off valve 51 functions as a mutual on-off control valve 33 because it prohibits the movement of hydraulic fluid 200 from the first hydraulic chamber 21 to the second hydraulic chamber 22. Also, the second on-off valve 52 functions as the first on-off control valve 31 because it prohibits the movement of hydraulic fluid 200 from the first hydraulic chamber 21 to the accumulator 38.

[0094] The pressure from the first hydraulic chamber 21, stored in the buffer 62, acts on the back surface 52b of the second on-off valve 52. Since the pressure from the first hydraulic chamber 21 acting on the back surface 52b of the second on-off valve 52 is higher than the pressure from the second hydraulic chamber 22 acting on the front surface 52a of the second on-off valve 52, the second on-off valve 52 closes. At this time, the second on-off valve 52 prevents the movement of hydraulic fluid 200 from the second hydraulic chamber 22, and thus functions as a second on-off control valve 32.

[0095] <Second Hydraulic Circuit Configuration> The second hydraulic circuit configuration H2 is achieved when the first on-off valve 51 is open and the second on-off valve 52 is closed. The pressure in the first hydraulic chamber 21 is higher than the pressure in the second hydraulic chamber 22, but the pressure in the first hydraulic chamber 21 has begun to decrease. A check valve 66 is provided in the flow path between the buffer 62 and the first hydraulic chamber 21. This check valve 66 maintains a high pressure state in the buffer 62. In this state, the pressure from the buffer 62 acting on the left side 54a of the pilot-operated valve 54 (the maximum pressure in the first hydraulic chamber 21) becomes higher than the pressure in the first hydraulic chamber 21 acting on the right side 54b of the pilot-operated valve 54. As a result, the pilot-operated valve 54 opens. When the pilot-operated valve 54 opens, the pressure acting on the back surface 51b of the first on-off valve 51 becomes lower than the pressure acting on the front surface 51a of the first on-off valve 51, so the first on-off valve 51 opens. As a result, a flow path is formed from the first hydraulic chamber 21 through the directional control valve 55 and the first on-off valve 51. This flow path corresponds to the mutual flow path P3 shown in Figure 2. At this time, the first on-off valve 51 allows the movement of hydraulic fluid 200 from the first hydraulic chamber 21 to the second hydraulic chamber 22, and therefore functions as a mutual on-off control valve 33.

[0096] Furthermore, the pressure from the buffer 62 acting on the back surface 52b of the second on-off valve 52 (the maximum pressure of the first hydraulic chamber 21) is higher than the decreasing pressure of the first hydraulic chamber 21 acting on the front surface 52a of the second on-off valve 52. Therefore, the second on-off valve 52 is closed. At this time, the second on-off valve 52 prevents the movement of hydraulic fluid 200 from the second hydraulic chamber 22, and thus functions as the second on-off control valve 32. In other words, whether the second on-off valve 52 functions as the first on-off control valve 31 or the second on-off control valve 32 is determined by the state of the directional control valve 55. Therefore, in the first embodiment, the first on-off control valve 31 and the second on-off control valve 32 shown in Figure 2, etc., are realized by a single second on-off valve 52.

[0097] <Third hydraulic circuit configuration> The third hydraulic circuit configuration H3 is achieved when the first on-off valve 51 is closed and the second on-off valve 52 is open. Assume that the pressure in the first hydraulic chamber 21 is in equilibrium with the pressure in the second hydraulic chamber 22, and furthermore, the pressure in the second hydraulic chamber 22 is slightly greater than the pressure in the first hydraulic chamber 21. In this state, first, the pressure acting on the left side 55a of the directional control valve 55 is greater than the pressure acting on the right side 55b, so the first hydraulic chamber 21 is connected to the front surface 52a of the second on-off valve 52 and the second hydraulic chamber 22 is connected to the front surface 51a of the first on-off valve 51. During this time, when the pressure in the first hydraulic chamber 21 is in equilibrium with the pressure in the second hydraulic chamber 22, the pressures acting on the left side 53a and the right side 53b of the first switching valve 53 are also in equilibrium. As a result, the buffer 62 of the first switching valve 53 is connected to the accumulator 38. As a result, the pressure acting on the left side 54a of the pilot-operated valve 54 balances with the pressure acting on the right side 54b of the pilot-operated valve 54, and the spring on the right side 54b closes the pilot-operated valve 54. Consequently, the first on-off valve 51 closes. At this time, the first on-off valve 51 functions as a mutual on-off control valve 33 because it prevents the movement of hydraulic fluid 200 from the second hydraulic chamber 22 to the first hydraulic chamber 21. Furthermore, when the pressure accumulated in the buffer 62 is released, the pressure acting on the back surface 52b of the second on-off valve 52 becomes lower than the pressure in the first hydraulic chamber 21 that has reached a balanced state acting on the front surface 52a of the second on-off valve 52. Therefore, the second on-off valve 52 opens, and a flow path is formed from the first hydraulic chamber 21 to the accumulator 38. This flow path corresponds to the first open flow path P1 shown in Figure 2. At this time, the second on-off valve 52 functions as the first on-off control valve 31 because it allows the movement of the hydraulic fluid 200 from the first hydraulic chamber 21 to the accumulator 38.

[0098] Even the hydraulic damper 1A according to the first embodiment can perform the same operation as the hydraulic damper 1 according to the embodiment. Therefore, the hydraulic damper 1A according to the first embodiment can improve energy absorption while simplifying the configuration of the hydraulic damper 1, similar to the hydraulic damper 1 according to the embodiment.

[0099] <Second Example> Figure 9 is a hydraulic circuit diagram of the hydraulic damper 1B according to the second embodiment. In the hydraulic damper 1B, the opening and closing of the first on-off valve 51 and the second on-off valve 52 are controlled by the controller 71. The hydraulic damper 1B according to the second embodiment is a semi-active type.

[0100] The hydraulic adjustment module 3B of the second embodiment includes a first on-off valve 51, a second on-off valve 52, a directional control valve 55, a first solenoid valve 69, and a second solenoid valve 70 as elements constituting the hydraulic circuit. Furthermore, the hydraulic adjustment module 3B of the second embodiment further includes an orifice 74 and a variable orifice 75 associated with the second on-off valve 52. The arrangement and function of the first on-off valve 51, the second on-off valve 52, and the directional control valve 55 are generally the same as in the first embodiment, so a detailed explanation is omitted. The first solenoid valve 69 is connected between the back surface 51b of the first on-off valve 51 and the accumulator 38, and switches the opening and closing of the first on-off valve 51 to each other. The second solenoid valve 70 is connected between the back surface 52b of the second on-off valve 52 and the accumulator 38, and switches the opening and closing of the second on-off valve 52 to each other. The hydraulic adjustment module 3B of the second embodiment may also have a displacement meter 79 for measuring the displacement of the piston rod 25.

[0101] The first solenoid valve 69 and the second solenoid valve 70 switch between open and closed states in response to the first control signal C69 and the second control signal C70 provided by the controller 71. For example, when the first solenoid valve 69 is closed, the first on-off valve 51 is also closed. When the first solenoid valve 69 is open, the first on-off valve 51 is also open.

[0102] The hydraulic adjustment module 3B of the second embodiment includes a controller 71, a first pressure sensor 72, and a second pressure sensor 73 as elements for controlling the hydraulic circuit. The first pressure sensor 72 obtains a first pressure value D21 of the first hydraulic chamber 21 and passes the first pressure value D21 to the controller 71. The second pressure sensor 73 obtains a second pressure value D22 of the second hydraulic chamber 22 and passes the second pressure value D22 to the controller 71.

[0103] The controller 71 generates a first control signal C69 and a second control signal C70 using the first pressure value D21 and the second pressure value D22. The controller 71 then provides the first control signal C69 to the first solenoid valve 69 and the second control signal C70 to the second solenoid valve 70.

[0104] <First Hydraulic Circuit Configuration> The controller 71 controls the first control signal C69 and the second control signal C70 to realize the first hydraulic circuit configuration H1 when the following conditions are met. Condition: When the first pressure value D21 and the second pressure value D22 are equal to each other, and the first pressure value D21 and the second pressure value D22 are also equal to the pressure of the accumulator 38. Or, when both the first pressure value D21 and the second pressure value D22 are below a predetermined threshold. Condition: When either the first pressure value D21 or the second pressure value D22 is increasing over time.

[0105] <Second Hydraulic Circuit Configuration> The controller 71 outputs a first control signal C69 to the first solenoid valve 69. The controller 71 does not output a second control signal C70 to the second solenoid valve 70. As a result, the first on-off valve 51 opens and the second on-off valve 52 closes, thus realizing the second hydraulic circuit configuration H2. The controller 71 outputs the first control signal C69 and does not output the second control signal C70 in order to realize the second hydraulic circuit configuration H2 when the following conditions are met. Condition: When the larger of the two pressure values, D21 (first pressure value) and D22 (second pressure value), begins to decrease from its maximum value over time.

[0106] <Third hydraulic circuit configuration> The controller 71 does not output the first control signal C69 to the first solenoid valve 69. The controller 71 outputs the second control signal C70 to the second solenoid valve 70 to open the second solenoid valve 70. As a result, the first on-off valve 51 closes and the second on-off valve 52 opens, thus realizing the third hydraulic circuit configuration H3. The controller 71 does not output the first control signal C69 and outputs the second control signal C70 in order to realize the third hydraulic circuit configuration H3 when the following conditions are met. Condition: When the first pressure value D21 and the second pressure value D22 are equal to each other, and both the first pressure value D21 and the second pressure value D22 are higher than the pressure of the accumulator 38. Or, when both the first pressure value D21 and the second pressure value D22 are higher than a predetermined threshold.

[0107] Even the hydraulic damper 1B according to the second embodiment can perform the same operation as the hydraulic damper 1 according to the embodiment by instruction from the controller 71. The hydraulic damper 1 according to the second embodiment is composed of a solenoid valve, a pressure sensor, and a controller, etc., which simplifies the overall structure of the hydraulic damper while improving the amount of energy absorbed. Furthermore, compared to the hydraulic damper 1A according to the first modified example, a control circuit including a pilot operating valve 54 and a buffer 62 for controlling the mutual opening and closing control valve 33 is not required, thus further simplifying the mechanism of the hydraulic damper.

[0108] <Third Example> Figure 10 shows a hydraulic damper 1C according to the third embodiment. In the hydraulic damper 1C, the opening and closing of the first on-off valve 51 is controlled by a pilot-operated valve 54, and the opening and closing of the second on-off valve 52 is controlled by a controller 71. The hydraulic damper 1C according to the third embodiment is a hybrid type.

[0109] The hydraulic adjustment module 3C of the third embodiment includes, as elements constituting the hydraulic circuit, a first on-off valve 51, a second on-off valve 52, a directional control valve 55, a pilot-operated valve 54, and a second solenoid valve 70. Furthermore, the hydraulic adjustment module 3C of the third embodiment further includes a variable orifice 75 attached to the second solenoid valve 70. The arrangement and function of these elements are generally the same as those of the first and second embodiments, so a detailed explanation is omitted.

[0110] The second solenoid valve 70 switches from closed to open when it receives the second control signal C70 from the controller 71. When the second solenoid valve 70 is closed, the second on-off valve 52 is also closed. When the second solenoid valve 70 is open, the second on-off valve 52 is also open.

[0111] <First Hydraulic Circuit Configuration> The first hydraulic circuit configuration H1 is in a state where the first on-off valve 51 is closed and the second on-off valve 52 is also closed. The mechanism for closing the first on-off valve 51 is the same as that described in the first embodiment. The mechanism for closing the second on-off valve 52 is the same as that described in the second embodiment.

[0112] <Second Hydraulic Circuit Configuration> In the second hydraulic circuit configuration H2, the first on-off valve 51 is open and the second on-off valve 52 is closed. The mechanism for opening the first on-off valve 51 is the same as that described in the first embodiment. The mechanism for closing the second on-off valve 52 is the same as that described in the second embodiment.

[0113] <Third hydraulic circuit configuration> In the third hydraulic circuit configuration H3, the first on-off valve 51 is closed and the second on-off valve 52 is open. The mechanism for closing the first on-off valve 51 is the same as that described in the first embodiment. The mechanism for opening the second on-off valve 52 is the same as that described in the second embodiment.

[0114] Even the hydraulic damper 1C according to the third embodiment can perform the same operation as the hydraulic damper 1 according to the embodiment. Therefore, similar to the hydraulic damper 1 according to the embodiment, it is possible to improve the energy absorption amount while simplifying the structure of the hydraulic damper.

[0115] <Fourth Example> Figure 11 shows a hydraulic damper 1D according to the fourth embodiment. The hydraulic damper 1D of the fourth embodiment is obtained by replacing the second on-off valve 52 with a second switching valve 78 in the hydraulic adjustment module 3A of the hydraulic damper 1A of the first embodiment. The second switching valve 78 is, for example, a spool valve.

[0116] The hydraulic adjustment module 3D of the fourth embodiment includes a first on-off valve 51, a directional control valve 55, a pilot-operated valve 54, a first switching valve 53, and a second switching valve 78 as elements constituting the hydraulic circuit. The arrangement and function of the first on-off valve 51, pilot-operated valve 54, directional control valve 55, and first switching valve 53 are generally the same as in the first embodiment, so a detailed explanation is omitted.

[0117] The second switching valve 78 corresponds to the first on / off control valve 31 or the second on / off control valve 32 shown in Figure 3. The second switching valve 78 is located between the directional control valve 55 and the accumulator 38. The second switching valve 78 connects the first hydraulic chamber 21 or the second hydraulic chamber 22 to the accumulator 38 depending on the relationship between the pressure of the first hydraulic chamber 21 and the pressure of the second hydraulic chamber 22. Specifically, the second switching valve 78 switches between a configuration in which the first hydraulic chamber 21 or the second hydraulic chamber 22 is connected to the accumulator 38 and a configuration in which the first hydraulic chamber 21 or the second hydraulic chamber 22 is disconnected from the accumulator 38. When the pressure of the first hydraulic chamber 21 is higher than the pressure of the second hydraulic chamber 22, the second switching valve 78 disconnects the second hydraulic chamber 22 from the accumulator 38. Furthermore, the second switching valve 78 disconnects the first hydraulic chamber 21 from the accumulator 38 when the pressure in the second hydraulic chamber 22 is higher than the pressure in the first hydraulic chamber 21. In addition, the second switching valve 78 connects either the first hydraulic chamber 21 or the second hydraulic chamber 22 to the accumulator 38 when the pressure in the first hydraulic chamber 21 is equal to the pressure in the second hydraulic chamber 22.

[0118] <First Hydraulic Circuit Configuration> The first hydraulic circuit configuration H1 is a state in which the first on-off valve 51 is closed and the second switching valve 78 is also closed. In other words, the first hydraulic circuit configuration H1 is a state in which the flow path between the low-pressure hydraulic chamber of the first hydraulic chamber 21 and the second hydraulic chamber 22 and the accumulator 38 is closed. The mechanism for closing the first on-off valve 51 is the same as that of the first on-off valve 51 described in the first embodiment. For example, in the second state ST2, when the pressure in the first hydraulic chamber 21 is high, the pressure in the first hydraulic chamber 21 is higher than the pressure in the second hydraulic chamber 22, so the second switching valve 78 is closed.

[0119] <Second Hydraulic Circuit Configuration> In the second hydraulic circuit configuration H2, the first on-off valve 51 is open and the second switching valve 78 is closed. The mechanism for opening the first on-off valve 51 is the same as that described in the first embodiment. After the first on-off valve 51 is opened, for example, when the hydraulic fluid 200 moves from the first hydraulic chamber 21, which has a relatively higher pressure, to the second hydraulic chamber 22, which has a relatively lower pressure, the pressure difference between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 decreases over time, but the pressure in the first hydraulic chamber 21 remains higher than the pressure in the second hydraulic chamber 22. Therefore, the second switching valve 78 is closed.

[0120] <Third hydraulic circuit configuration> In the third hydraulic circuit configuration H3, the first on-off valve 51 is closed and the second switching valve 78 is open. The mechanism for closing the first on-off valve 51 is the same as that described in the first embodiment. For example, as the pressure difference between the pressure in the first hydraulic chamber 21 and the pressure in the second hydraulic chamber 22 decreases over time, when the pressure in the first hydraulic chamber 21 becomes equal to the pressure in the second hydraulic chamber 22, the pressure acting on the left side 78a of the second switching valve 78 becomes equal to the pressure acting on the right side 78b of the second switching valve 78. As a result, the second switching valve 78 opens.

[0121] Even the hydraulic damper 1D according to the fourth embodiment can perform the same operation as the hydraulic damper 1 according to the embodiment. Therefore, similar to the hydraulic damper 1 according to the embodiment, it is possible to improve the energy absorption amount while simplifying the structure of the hydraulic damper.

[0122] <Example 5> Figure 12 shows a hydraulic damper 1E according to the fifth embodiment. The hydraulic adjustment module 3E of the fifth embodiment has a first on-off valve 51E which includes a poppet valve 51p and a spool valve 51s. The hydraulic adjustment module 3E of the fifth embodiment also has orifices 79 and 80 attached to the first on-off valve 51E. Furthermore, the hydraulic adjustment module 3E of the fifth embodiment has a check valve 81 attached to the second on-off valve 52.

[0123] The spool valve 51s is located in the passage P9 connecting the first hydraulic chamber 21 and the second hydraulic chamber 22. The spool valve 51s allows the movement of hydraulic fluid between the first hydraulic chamber 21 and the second hydraulic chamber 22 during minute vibrations such as those caused by wind. That is, during minute vibrations such as those caused by wind, even if the pilot operating valve 54 is open, the poppet valve 51p may not open, and the movement of hydraulic fluid between the first hydraulic chamber 21 and the second hydraulic chamber 22 may not be permitted. In this case, when the pilot operating valve 54 is open and the poppet valve 51p is closed, the spool valve 51s allows the movement of hydraulic fluid between the first hydraulic chamber 21 and the second hydraulic chamber 22 in the passage P9. When the poppet valve 51p is open, the spool valve 51s switches to a closed state, which prohibits the movement of hydraulic fluid between the first hydraulic chamber 21 and the second hydraulic chamber 22 in the passage P9.

[0124] Even the hydraulic damper 1E according to the fifth embodiment can perform the same operation as the hydraulic damper 1 according to the embodiment. Therefore, similar to the hydraulic damper 1 according to the embodiment, it is possible to improve the energy absorption amount while simplifying the structure of the hydraulic damper.

[0125] The first on-off valve 51 includes a poppet valve 51p and a spool valve 51s. This allows the spool valve 51s to switch between opening, which allows the movement of hydraulic fluid between the first hydraulic chamber 21 and the second hydraulic chamber 22, and closing, which prohibits the movement of the hydraulic fluid, when a minute vibration acts on the valve that prevents the poppet valve 51p from operating. Thus, the amount of energy absorbed by the hydraulic damper when minute vibrations act on it can be improved.

[0126] <Variation> The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. For example, the accumulator 38 may be replaced with a hydraulic tank. Also, instead of moving the hydraulic fluid from the high-pressure first hydraulic chamber 21 to the low-pressure second hydraulic chamber 22, the hydraulic fluid may be moved from the first hydraulic chamber 21 to the hydraulic tank.

[0127] <Note> This disclosure also includes the following components:

[0128] This disclosure relates to a hydraulic damper comprising [1] a cylinder, a piston that reciprocates within the cylinder, hydraulic chambers provided on both sides of the piston, and a first on / off control valve connected to a flow path connecting the two hydraulic chambers, which can be switched between open and closed, The hydraulic damper is connected to the hydraulic cylinder and includes an accumulator capable of storing pressurized oil, The hydraulic damper is equipped with a second on / off control valve connected to a flow path that connects both hydraulic chambers and the accumulator, and which can be switched between open and closed. In a hydraulic damper, while the pressure in one hydraulic chamber is rising, all control valves remain closed and pressure is stored in a buffer. When the pressure in that hydraulic chamber begins to decrease, the first on-off control valve is opened, and when the pressure difference between the left and right hydraulic chambers is eliminated, the first on-off control valve closes again. This is a damping coefficient switching type hydraulic damper characterized by incorporating a mechanism that rapidly reduces the pressure in one cylinder chamber by opening the second on / off control valve provided in the flow path connecting the left and right cylinder chambers and the accumulator, thereby creating a differential pressure again, and then closing the second on / off control valve.

[0129] This disclosure is [2] "A hydraulic damper as described in [1] above, comprising a controller that receives a signal from a pressure gauge provided in the hydraulic damper and controls a solenoid valve that pilot-operates the on / off control valve, and enabling the on / off control of the second on / off control valve at the timing described in [1] above."

[0130] This disclosure is [3] "A hydraulic damper described in [1] above, characterized in that a spool valve that moves due to the pressure difference between the left and right cylinder chambers, or a pressure regulating valve that is opened by pilot operation by the spool valve, is used as the second on / off control valve to enable on / off control." [Explanation of Symbols]

[0131] 1, 1A, 1B, 1C, 1D, 1E… Hydraulic damper, 20… Internal space, 21… First hydraulic chamber, 22… Second hydraulic chamber, 23… Cylinder, 24… Piston, 25a, 25b… Piston rod, 3, 3A, 3B, 3C, 3D, 3E… Hydraulic adjustment module (hydraulic adjustment section, hydraulic adjustment device), 31… First on / off control valve, 32… Second on / off control valve, 33… Mutual on / off control valve, 38… Accumulator (pressure release section), 200… Hydraulic fluid, H1… First hydraulic circuit configuration, H2… Second hydraulic circuit configuration, H3… Third hydraulic circuit configuration, P1… First open passage, P2… Second open passage, P3… Mutual passage.

Claims

1. A cylinder having an internal space filled with hydraulic fluid, A piston is positioned inside the cylinder, dividing the internal space into a first hydraulic chamber and a second hydraulic chamber, and moving back and forth inside the cylinder. The system comprises a hydraulic adjustment unit connected to the first hydraulic chamber and the second hydraulic chamber, The hydraulic adjustment unit is A pressure release section is connected to the first hydraulic chamber via a first open passage and to the second hydraulic chamber via a second open passage, for releasing the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber. A mutual opening and closing control valve is provided in a mutual flow path, one end of which is connected to the first hydraulic chamber and the other end of which is connected to the second hydraulic chamber, and which switches between opening, which allows the movement of hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber and from the second hydraulic chamber to the first hydraulic chamber, and closing, which prohibits the movement of hydraulic fluid. A first on / off control valve is provided in the first open passage and switches between opening, which allows the movement of the hydraulic fluid from the first hydraulic chamber to the pressure release section, and closing, which prohibits the movement of the hydraulic fluid. A hydraulic damper having a second on / off control valve provided in the second open passage, which switches between opening to allow the movement of the hydraulic fluid from the second hydraulic chamber to the pressure release section and closing to prohibit the movement of the hydraulic fluid.

2. The hydraulic adjustment unit is A first hydraulic circuit configuration in which the mutual on / off control valve is closed, the first on / off control valve is closed, and the second on / off control valve is closed, A second hydraulic circuit configuration in which the mutual opening / closing control valve is open, the first opening / closing control valve is closed, and the second opening / closing control valve is closed, The hydraulic damper according to claim 1, wherein the mutual opening / closing control valve is closed, and a third hydraulic circuit configuration is configured such that one of the first opening / closing control valve and the second opening / closing control valve is open and the other is closed, and the two configurations are switched between each other.

3. The hydraulic adjustment unit is The hydraulic damper according to claim 2, which switches in the order of the first hydraulic circuit configuration, the second hydraulic circuit configuration, and the third hydraulic circuit configuration.

4. The hydraulic adjustment unit is The hydraulic damper according to claim 2, wherein the first hydraulic circuit configuration, the second hydraulic circuit configuration, and the third hydraulic circuit configuration are switched to each other based on the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber.

5. The hydraulic adjustment unit is When the pressure in the first hydraulic chamber increases in accordance with the movement of the piston, the first hydraulic circuit configuration is set as follows: When the direction of movement of the piston is reversed, the configuration switches from the first hydraulic circuit configuration to the second hydraulic circuit configuration in which the mutual opening / closing control valve is open and the first opening / closing control valve and the second opening / closing control valve are closed. The hydraulic damper according to claim 4, wherein the third hydraulic circuit configuration is such that when the differential pressure between the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber falls below a threshold, the first on / off control valve is open and the second on / off control valve is closed.

6. A hydraulic adjustment device for a hydraulic damper comprising: a cylinder having an internal space filled with hydraulic fluid; and a piston disposed inside the cylinder, dividing the internal space into a first hydraulic chamber and a second hydraulic chamber, and moving back and forth inside the cylinder, A pressure release section is connected to the first hydraulic chamber via a first open passage and to the second hydraulic chamber via a second open passage, for releasing the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber. A mutual opening and closing control valve is provided in a mutual flow path, one end of which is connected to the first hydraulic chamber and the other end of which is connected to the second hydraulic chamber, and which switches between opening, which allows the movement of hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber and from the second hydraulic chamber to the first hydraulic chamber, and closing, which prohibits the movement of hydraulic fluid. A first on / off control valve is provided in the first open passage and switches between opening, which allows the movement of the hydraulic fluid from the first hydraulic chamber to the pressure release section, and closing, which prohibits the movement of the hydraulic fluid. A hydraulic adjustment device comprising: a second open-flow channel provided therein, which switches between opening to allow the movement of the hydraulic fluid from the second hydraulic chamber to the pressure release section and closing to prohibit the movement of the hydraulic fluid.

7. A method for controlling a hydraulic damper comprising a cylinder having an internal space filled with hydraulic fluid, and a piston disposed inside the cylinder, dividing the internal space into a first hydraulic chamber and a second hydraulic chamber, and moving back and forth inside the cylinder, A first step is to prevent the outflow of the hydraulic fluid from the first and second hydraulic chambers when the pressure in the first hydraulic chamber increases in accordance with the movement of the piston, A second step is to allow the movement of the hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber when the direction of movement of the piston is reversed, A method for controlling a hydraulic damper, comprising: a third step of prohibiting the movement of the hydraulic fluid from the first hydraulic chamber to the second hydraulic chamber and releasing the pressure in the first hydraulic chamber when the differential pressure between the pressure in the first hydraulic chamber and the pressure in the second hydraulic chamber falls below a threshold.

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