Mass damper using pressure motor

Abstract

To provide a mass damper using a pressure motor capable of easily and surely discharging air from a pipe of a working fluid after finishing assembling work of the mass damper.SOLUTION: The mass damper 1A has the housing 6 provided in the communication path 4 communicating with the first and second fluid chambers 2f and 2g, and includes the geared motor 5 that converts the flow of the working oil HF into rotational motion, the drain pipe 61 connected to the drain path of the housing 6, and the first to third hydraulic couplers 63 to 65 provided on both sides of the housing 6 of the communication path 4 and in the drain path. After the air in the gear motor 5 and the drain pipe 61 is discharged to the pressure accumulating chamber 23 of the first accumulator 21 and the communication passage 4 by setting the first and second hydraulic couplers 63, 64 to the open mode and the third hydraulic coupler 65 to the press-in mode, the air in the pressure accumulating chamber 23 of the first accumulator 21 and the communication passage 4 is discharged to the outside from one of the hydraulic couplers 63, 64 by setting one of the hydraulic couplers 63, 64 to the open mode and the other to the press-in mode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mass damper that uses a pressure motor to convert the pressure of a working fluid that flows due to vibration into the rotational motion of a rotating mass in order to suppress vibration of a structure or the like, and in particular to a mass damper that has an air vent function to discharge air that has become mixed in the piping of the working fluid. [Background technology]

[0002] A known example of a conventional pressure motor-type mass damper is disclosed in Patent Document 1. This mass damper uses a gear motor as a pressure motor and includes a cylinder filled with a working fluid, a piston slidably disposed within the cylinder and dividing the interior of the cylinder into first and second fluid chambers, a communication passage bypassing the piston and communicating with the first and second fluid chambers, a pressure motor having a housing disposed in the communication passage and converting the pressure of the working fluid into rotational motion, and a rotary mass connected to the pressure motor. The cylinder and piston are connected to first and second portions of a structure. Furthermore, in the mass damper disclosed in Patent Document 2, also disclosed by the present applicant, a drain pipe is provided between a drain passage of the housing and the communication passage to discharge the working fluid from the housing to the first or second fluid chamber.

[0003] In this configuration, when the structure vibrates, the piston slides within the cylinder in response to the relative displacement of the first and second parts, causing the working fluid to flow from the first or second fluid chamber into the communicating passage, and the pressure of the working fluid caused by this flow is converted into rotational motion of the pressure motor, driving the rotating mass to rotate, thereby exerting a vibration suppression effect on the structure. Furthermore, when the pressure inside the housing increases during operation of the mass damper, the working fluid is discharged into the first or second fluid chamber through the drain pipe and the communicating passage, preventing the pressure inside the housing from increasing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-94680 [Patent Document 2] Japanese Patent Application Publication No. 2023-91698 Summary of the Invention [Problem to be solved by the invention]

[0005] In hydraulic equipment, it is generally known that when air gets into the hydraulic oil piping, cavitation occurs as the hydraulic oil pressure drops, resulting in abnormal noise (rumble), vibration, and malfunction. In contrast, with the conventional mass damper described above, it is inevitable that a certain amount of air will get into the piping when assembling the gear motor, connecting passage, drain piping, etc., making it difficult to fill the piping with hydraulic oil completely free of air. Air is particularly likely to accumulate in the bent portion of the drain piping connecting the housing's drain passage to the connecting passage. In contrast, conventional mass dampers do not have a means for effectively removing trapped air from the piping. Therefore, cavitation occurs during mass damper operation, causing problems such as abnormal noise, vibration, and malfunction when the gear motor rotates.

[0006] The present invention has been made to solve the above-mentioned problems, and has as its object to provide a mass damper using a pressure motor that can easily and reliably discharge air from the working fluid piping after the assembly work of the mass damper is completed, thereby preventing the occurrence of cavitation and the resulting malfunctions during operation of the mass damper. [Means for solving the problem]

[0007] To achieve this object, a mass damper using a pressure motor according to the invention of claim 1 comprises a cylinder filled with a working fluid, a piston slidably provided within the cylinder and dividing the interior of the cylinder into a first fluid chamber and a second fluid chamber, a communication passage bypassing the piston and communicating with the first and second fluid chambers, a housing having a drain passage communicating with the communication passage and for discharging the working fluid, a rotating body accommodated in the housing, a pressure motor for converting the pressure of the working fluid flowing through the communication passage as the piston slides into rotational motion of the rotating body, a rotating mass that is rotationally driven by the pressure motor and thereby exerts a vibration suppressing effect, and a rotating mass connected at one end to the drain passage of the housing and at the other end to the working fluid the pressure motor and the drain piping are provided in communication with a drain section from which hydraulic fluid is discharged, first and second hydraulic couplers provided on both sides of the housing of the communication passage, and a third hydraulic coupler provided in the drain passage, and the air in the pressure motor and the drain piping is discharged into the communication passage by setting the first and second hydraulic couplers in an open mode and the third hydraulic coupler in a press-in mode in which the hydraulic fluid is pressurized, and then by setting one of the first and second hydraulic couplers in the open mode, the other of the first and second hydraulic couplers in the press-in mode, and the third hydraulic coupler in a closed mode, the air in the communication passage is discharged to the outside from the open one of the first and second hydraulic couplers.

[0008] The mass damper of the present invention uses a pressure motor, and as the piston slides in the cylinder, working fluid flows from the first or second fluid chamber to the communication passage and the housing of the pressure motor. The pressure of the working fluid caused by this flow is converted into rotational motion of the rotor of the pressure motor, which rotates and drives the rotating mass, thereby achieving a vibration suppression effect. Furthermore, when the pressure inside the housing increases during operation of the mass damper, the working fluid inside the housing is discharged from the drain passage through the drain pipe to the discharge part, thereby preventing the pressure inside the housing from increasing.

[0009] Furthermore, according to the present invention, first and second hydraulic couplers are provided on both sides of the housing of the communicating passage, and a third hydraulic coupler is provided in the drain passage. Then, for example, after the assembly work of the mass damper (assembly of components and injection of hydraulic fluid) is completed, the first and second hydraulic couplers are set to an open mode and the third hydraulic coupler is set to a press-in mode in which the hydraulic fluid is pressurized, thereby discharging air from the pressure motor and the drain piping into the communicating passage. Thereafter, one of the first and second hydraulic couplers is set to the open mode, the other of the first and second hydraulic couplers is set to the press-in mode, and the third hydraulic coupler is set to a closed mode, thereby discharging air from the open one of the first and second hydraulic couplers to the outside.

[0010] Hydraulic couplers generally have the ability to automatically open and close in response to the connection and disconnection of the hose-side coupler connected to the hydraulic hose, and to minimize the intrusion of air into the coupler during installation. Therefore, by setting the modes of the first to third hydraulic couplers as described above after completing the assembly of the mass damper, air can be easily and reliably discharged to the outside from the working fluid piping, such as the pressure motor and drain piping, while minimizing the intrusion of air during mode switching. As a result, the occurrence of cavitation during operation of the mass damper and the resulting malfunctions can be prevented.

[0011] The invention according to claim 2 is a mass damper using a pressure motor according to claim 1, characterized in that the communication passage has a pair of vertical sections that communicate with the first and second fluid chambers, respectively, and a horizontal section that is connected between the upper ends of the pair of vertical sections, and the first and second hydraulic couplers are respectively disposed near the connection between the pair of vertical sections and the horizontal section.

[0012] According to this configuration, the first and second hydraulic couplers are positioned near the connection between a pair of vertical and horizontal sections of the communicating passage, so that air discharged into the communicating passage can be guided to the upper first and second hydraulic couplers without being mixed into the first and second fluid chambers below the vertical sections, thereby enabling smooth air bleeding.

[0013] In order to achieve the above object, a mass damper using a pressure motor according to the invention of claim 3 comprises a cylinder filled with a working fluid, a piston slidably provided within the cylinder and dividing the interior of the cylinder into a first fluid chamber and a second fluid chamber, a housing having a communication passage bypassing the piston and communicating with the first and second fluid chambers, a communication passage communicating with the communication passage and for discharging the working fluid, and a rotor accommodated in the housing, the pressure motor converting the pressure of the working fluid flowing through the communication passage as the piston slides into rotational motion of the rotor, a rotating mass that is rotationally driven by the pressure motor and exhibits a vibration suppression effect, and a horizontally extending rotor connected to the drain passage of the housing. The drain pipe has a housing-side passage portion and a discharge-side passage portion extending downward from near the end of the housing-side passage portion and communicating with the discharge portion from which the working fluid is discharged; a pipe coupling tee having first and second pipe portions extending coaxially with each other and a third pipe portion extending at a right angle from between the first and second pipe portions, the first pipe portion having a tapered threaded hole formed therein, the second pipe portion being connected to an upper end of the discharge-side pipe portion of the drain pipe, and the third pipe portion being connected to an end of the housing-side pipe portion; a tapered plug having a tapered thread screwed into the threaded hole of the first pipe portion; and a check valve provided in the discharge-side passage portion of the drain pipe and allowing only the flow of working fluid from the housing side to the discharge side.

[0014] In the mass damper of the present invention, the drain pipe has a housing-side passage connected to the drain passage of the housing and a discharge-portion-side passage extending downward from near the end of the housing-side passage, and the discharge-portion-side passage communicates with the discharge port from which the working fluid is discharged and is provided with a check valve that allows the working fluid to flow only from the housing side to the discharge port. According to this configuration, when the pressure inside the housing rises, the check valve opens and the working fluid inside the housing is discharged from the drain passage to the discharge port via the housing-side passage and the discharge-portion-side passage of the drain pipe, thereby releasing the pressure inside the housing and preventing it from becoming too high.

[0015] According to the present invention, the housing-side passage portion and the discharge-side passage portion of the drain pipe are connected via a pipe joint tee. The pipe joint tee has first and second pipe portions that are coaxial with each other and a third pipe portion that is perpendicular to the first and second pipe portions, with a tapered threaded hole formed in the upper first pipe portion, the lower second pipe portion connected to the upper end of the discharge-side pipe portion, and the third pipe portion connected to the end of the housing-side pipe portion. A tapered screw is threaded into the threaded hole of the first pipe portion, and these threaded hole and screw form a tapered plug.

[0016] With this configuration, for example, after the assembly of the mass damper is completed, the tapered plug can be loosened while the working fluid is still in the tapered plug. This allows air that has collected from the housing, the drain passage, and other components and is present in the drain piping to be guided above the tapered plug and easily and reliably discharged to the outside. Then, by tightening the tapered plug, the high airtightness of the tapered plug prevents air from entering from the outside through the tapered plug. This keeps the piping of the mass damper air-free, thereby preventing the occurrence of cavitation and resulting problems during operation of the mass damper.

[0017] The invention according to claim 4 is characterized in that, in the mass damper using the pressure motor according to claim 3, the check valve has a valve body, and is configured so that, with the tapered plug removed, the valve body is manually pushed down to open the valve, thereby discharging air present below the check valve upward.

[0018] According to this configuration, with the tapered plug removed, the valve element of the check valve can be manually pushed down to open the valve, thereby directing air that has collected from the discharge portion of the working fluid, etc., and is present below the check valve in the discharge portion-side pipeline section upward and discharging it to the outside via the tapered plug.

[0019] The invention according to claim 5 is a mass damper using a pressure motor according to claim 3 or 4, further comprising an accumulator arranged above a housing-side passage portion of the drain pipe for storing a part of the pressure of the working fluid in the drain pipe, wherein the accumulator further comprises a casing communicating with the housing-side passage portion, a piston provided within the casing so as to be slidable in the vertical direction and defining a pressure accumulator chamber in a lower portion within the casing, and a tapered plug for the accumulator having a tapered screw hole formed to penetrate the piston in the vertical direction, and a tapered screw screwed into the screw hole from above.

[0020] In this configuration, when the pressure of the working fluid in the drain pipe rises, the working fluid flows from the housing-side passage into the accumulator's pressure accumulator chamber and compresses the set spring via the piston, thereby storing a portion of the working fluid's pressure in the accumulator, more reliably preventing pressure buildup inside the housing. Furthermore, in this configuration, the accumulator is disposed above the housing-side passage of the drain pipe, making it difficult to discharge air present in the accumulator's pressure accumulator chamber using the tapered plug of claim 1, which is disposed at approximately the same height as the housing-side passage. In this regard, according to this configuration, the accumulator piston is provided with an accumulator tapered plug, and by loosening this tapered plug, air accumulated in the accumulator's pressure accumulator chamber can be guided above the piston and easily discharged.

[0021] The invention according to claim 6 is characterized in that the mass damper using the pressure motor according to claim 3 or 4 further comprises an air-bleeding check valve that is provided at the top of the communicating passage and that discharges air present in the communicating passage by manually pushing down the ball.

[0022] With this configuration, by manually pushing down the ball of the check valve for bleeding air, air that has collected from the first fluid chamber, the second fluid chamber, etc. and is present in the connecting passage can be guided above the check valve and discharged. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a partially cutaway longitudinal sectional view of a mass damper according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a vertical cross-sectional view showing a mass damper according to a second embodiment, with a portion cut away. [Figure 3] FIG. 11 is a vertical cross-sectional view showing a mass damper according to a third embodiment, with a portion cut away. [Figure 4] FIG. 10 is a vertical cross-sectional view showing a mass damper according to a fourth embodiment, with a portion cut away. [Figure 5] FIG. 10 is a vertical cross-sectional view showing a mass damper according to a fifth embodiment, with a portion cut away. [Figure 6] FIG. 10 is a vertical cross-sectional view showing a mass damper according to a sixth embodiment, with a portion cut away. [Figure 7] FIG. 13 is a vertical cross-sectional view showing a mass damper according to a seventh embodiment, with a portion cut away. DETAILED DESCRIPTION OF THE INVENTION

[0024] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. As shown in Fig. 1, a mass damper 1A according to a first embodiment of the present invention includes a cylinder 2, a piston 3 slidably provided within the cylinder 2, an inverted U-shaped communication passage 4 that bypasses the piston 3 and communicates with the inside of the cylinder 2, a gear motor 5 serving as a pressure motor and disposed within the communication passage 4, and a flywheel 9 connected to an output shaft 8 of the gear motor 5. The communication passage 4 is composed of a pair of vertical portions 4a, 4a that communicate with first and second fluid chambers 2f, 2g (described later) of the cylinder 2, and a horizontal portion 4b that connects the upper ends of the vertical portions 4a, 4a.

[0025] The cylinder 2 has a cylindrical peripheral wall 2a and first and second end walls 2b, 2c integrally provided at both ends of the peripheral wall 2a, and these three walls 2a-2c define the internal space of the cylinder 2. The central portion of the peripheral wall 2a in the axial direction forms a rod fitting portion 2d with a large wall thickness (small inner diameter), and the space between the rod fitting portion 2d and the second end wall 2c forms a rod accommodating portion 2e. A second mounting fixture FL2 is attached to the second end wall 2c via a ball joint BJ.

[0026] The piston 3 is axially slidably disposed within the cylinder 2, dividing the internal space of the cylinder 2 into a first fluid chamber 2f and a second fluid chamber 2g. The first and second fluid chambers 2f, 2g and the communication passage 4 are filled with hydraulic oil HF. The hydraulic oil HF is a normal hydraulic oil with an appropriate viscosity.

[0027] A piston rod 10 is integrally and concentrically provided with the piston 3. The piston rod 10 is composed of a first rod portion 10a extending from the piston 3 to one side in the axial direction (the left side in FIG. 1) and a second rod portion 10b extending to the other side (the right side in FIG. 1). The first rod portion 10a is supported by the first end wall 2b while penetrating it in a liquid-tight manner, and partially protrudes outside the cylinder 2. A first mounting fixture FL1 is attached to the tip end of the first rod portion 10a via a ball joint BJ. The second rod portion 10b is supported by the rod fitting portion 2d of the cylinder 2 while being fitted in a liquid-tight manner, and is partially accommodated in the rod accommodation portion 2e.

[0028] The second rod portion 10b is provided with an accumulator (hereinafter referred to as the "first accumulator") 21 to accommodate the temperature expansion of the hydraulic oil HF. The first accumulator 21 temporarily stores a portion of the pressure inside the cylinder 2 that increases with the temperature rise of the hydraulic oil HF, etc. The first accumulator 21 includes a hollow casing portion 22 formed in approximately two-thirds of the range toward the tip of the second rod portion 10b, a piston 24 slidably provided within the casing portion 22 and defining a pressure accumulator chamber 23 on the piston 3 side, and a set spring 25 that biases the piston 24 toward the pressure accumulator chamber 23. A rod communication hole 10c is also formed coaxially in the second rod portion 10b. One end of the rod communication hole 10c is connected to the pressure accumulator chamber 23, and the other end is connected to the piston communication hole 3a of the piston 3.

[0029] Meanwhile, the piston 3 is formed with first and second communication holes that penetrate the piston 3 in the axial direction and communicate with the first and second fluid chambers 2f, 2g, a third communication hole that extends vertically to connect the first and second communication holes, and a piston communication hole 3a that extends from the center of the third communication hole to both sides in the axial direction and communicates with the rod communication hole 10c. The first communication hole is provided with check valves 26, 26 on both sides of the third communication hole. Each check valve 26 is configured to allow hydraulic oil HF to flow only from the third communication hole side to the first or second fluid chamber 2f, 2g side. The second communication hole is provided with orifices 27, 27 on both sides of the third communication hole.

[0030] In the above configuration, when the pressure inside the cylinder 2 increases due to a rise in the temperature of the hydraulic oil HF or the like, the hydraulic oil HF slowly flows from the first and second fluid chambers 2f, 2g through the second communication hole of the piston 3, the orifices 27, 27, the third communication hole, the piston communication hole 3a, and the rod communication hole 10c into the accumulator chamber 23 of the first accumulator 21. As a result, the set spring 25 is compressed via the piston 24, and a portion of the pressure inside the first and second fluid chambers 2f, 2g is stored in the accumulator 21, thereby avoiding problems caused by a rise in pressure due to a rise in the temperature of the hydraulic oil HF or the like.

[0031] When the temperature of the hydraulic oil HF drops from this state, the hydraulic oil HF in the accumulator chamber 23 is returned to the first and second fluid chambers 2f, 2g via the rod communication hole 10c, the piston communication hole 3a, the third communication hole, the opened check valves 26, 26, and the first communication hole, thereby releasing the pressure accumulated in the accumulator 21 and restoring the original state.

[0032] Furthermore, a first communication passage 3b and a second communication passage 3c for relief purposes are formed in the piston 3, penetrating in the axial direction. A first relief valve 11 and a second relief valve 12 are provided in the first and second communication passages 3b and 3c, respectively. The first and second relief valves 11 and 12 have the same configuration, are configured as normally closed valves, and include a valve body and a spring that biases the valve body in the valve closing direction.

[0033] The first relief valve 11 closes the first communication passage 3b until the pressure of the hydraulic oil HF in the first fluid chamber 2f reaches a predetermined pressure, and then opens the first communication passage 3b when the predetermined pressure is reached. This allows the pressure in the first fluid chamber 2f to escape to the second fluid chamber 2g via the first communication passage 3b, and is limited to a pressure equal to or lower than the predetermined pressure. Similarly, the second relief valve 12 closes the second communication passage 3c until the pressure in the second fluid chamber 2g reaches a predetermined pressure, and then opens the second communication passage 3c when the predetermined pressure is reached. This allows the pressure in the second fluid chamber 2g to escape to the first fluid chamber 2f via the second communication passage 3c, and is limited to a pressure equal to or lower than the predetermined pressure.

[0034] The gear motor 5 is, for example, an internal gear type and is arranged in the horizontal portion 4b of the communication passage 4. The gear motor 5 has a housing 6 that communicates with the communication passage 4 via two inlets and outlets 6a, 6a, a rotatable input gear and an output gear (neither shown) that are housed in the housing 6 and mesh with each other, and an output shaft 8 that is integral with the output gear. The housing 6 is supported on the peripheral wall 2a of the cylinder 2. A drain passage (not shown) for discharging the hydraulic oil HF is also provided within the housing 6. The output shaft 8 is supported liquid-tightly in the housing 6 via a seal (not shown). Note that an external gear type may be used as the gear motor 5 instead of the internal gear type.

[0035] The flywheel 9 is made of a material with a relatively large specific gravity, such as steel, and is formed, for example, in a disk shape. The flywheel 9 is provided integrally with the output shaft 8 and coaxially therewith.

[0036] The mass damper 1A also includes a drain hose 61 for discharging hydraulic oil HF from the housing 6. The drain hose 61 is flexible, with one end connected to a drain passage in the housing 6 and the other end connected to the first rod portion 10a of the piston rod 10, with the hose being attached in a loosened state overall. More specifically, the other end of the drain hose 61 is connected to a second rod communicating hole 10d formed in the first rod portion 10a. One end of the second rod communicating hole 10d opens to the outer peripheral surface of the first rod portion 10a, extends coaxially with the first rod portion 10a, and the other end communicates with the piston communicating hole 3a. The other end of the drain hose 61 is provided with a check valve 62 that allows only the flow of hydraulic oil HF and air from the housing 6 toward the piston rod 10.

[0037] To bleed air from the mass damper 1A, first and second hydraulic couplers 63, 64 are provided at the left and right ends of the horizontal section 4b of the communication passage 4 (the upper ends of each vertical section 4a), and a third hydraulic coupler 65 is provided in the drain passage of the housing 6. These hydraulic couplers 63-65 are paired with hose-side couplers (none of which are shown) to which hydraulic hoses are connected, and have the function (automatic opening and closing function) of opening the passage (opening the valve) when the hose-side coupler is attached and closing the passage (closing the valve) when the hose-side coupler is detached. Furthermore, because the connecting surfaces of the hydraulic couplers 63-65 and the hose-side couplers are flat, the intrusion of air into the interior during attachment and the dripping of liquid to the outside during detachment are minimized.

[0038] Furthermore, hydraulic hoses connected to the hose-side couplers include a press-in hose connected to a hydraulic oil tank or pump (neither of which are shown) for pressurizing hydraulic oil HF into the mass damper 1A, and a release hose that is open to the outside for discharging hydraulic oil HF and air from the mass damper 1A. With the above configuration, each of the first to third hydraulic couplers 63 to 65 can be set to one of the following three modes depending on whether or not the hose-side coupler is connected (connected / disconnected) and the type of hydraulic hose. A. Closed mode in which the hose side coupler and hydraulic hose are not connected and are closed B. Pressurization mode in which the hose side coupler and pressurization hose are connected and hydraulic oil HF is pressurized C. Open mode in which the hose side coupler and discharge hose are connected and open to the outside

[0039] 1, reference numeral 51 denotes a hydraulic oil filling hole formed in the rod fitting portion 2d of the cylinder 2 for filling the hydraulic oil HF into the second fluid chamber 2g, and reference numeral 52 denotes a check valve for preventing backflow provided near the inlet of the hydraulic oil filling hole 51. Reference numerals 53 and 53 also denote pedestals provided on the cylinder 2 for preventing the mass damper 1A from rotating or tipping over.

[0040] Although not shown, the mass damper 1A having the above configuration is attached, for example, between two relatively displaceable parts of a structure (for example, an upper beam and a lower beam) via first and second mounting fixtures FL1 and FL2, and is used as a seismic control device. The operation of the mass damper 1A will be described below.

[0041] 1 shows the initial state of the mass damper 1A, and when the structure vibrates during an earthquake or other event, the piston 3 reciprocates within the cylinder 2 in response to the relative displacement between the two parts to which the mass damper 1A is attached. As a result, the hydraulic oil HF within the first or second fluid chamber 2f, 2g is pushed out by the piston 3, flows into the communicating passage 4, and after flowing through the housing 6 of the gear motor 5, flows into the second or first fluid chamber 2g, 2f.

[0042] The pressure caused by the flow of this hydraulic oil HF is converted into rotational motion of the input gear and output gear of the gear motor 5, and the flywheel 9 integrated with the output shaft 8 is rotated, thereby exerting a rotational inertia mass effect (inertia force). In addition, a viscous damping effect (viscous force) is exerted due to the flow resistance when the hydraulic oil HF flows through the communicating passage 4, the inside of the gear motor 5, etc., and this, in addition to the rotational inertia mass effect, exerts an effect of suppressing vibration of the structure. The above operation can be similarly obtained in each of the mass dampers 1B to 1G of the second to seventh embodiments described below.

[0043] Furthermore, for example, when the response of the structure to a long-period earthquake motion input causes the mass damper 1A and the gear motor 5 to operate for a long period of time, the pressure inside the housing 6 increases and becomes greater than the pressure in the accumulator chamber 23 of the first accumulator 21, and the check valve 62 opens. This causes a portion of the hydraulic oil HF inside the housing 6 to be discharged to the accumulator chamber 23 of the first accumulator 21 via the drain passage inside the housing 6, the drain hose 61, the second rod communicating hole 10d, the piston communicating hole 3a, and the rod communicating hole 10c. As a result, the pressure inside the housing 6 is released to the first accumulator 21, preventing the pressure inside the housing 6 from increasing.

[0044] Furthermore, according to the mass damper 1A of this embodiment, after assembly, air can be bled from the piping of the hydraulic oil HF by setting the modes of the first to third hydraulic couplers 63 to 65. Air bleed is performed, for example, in the following procedure.

[0045] (1) Bleeding air from the cylinder unit A motor unit assembled from the communication passage 4, gear motor 5, and drain hose 61, and a cylinder unit assembled from the cylinder 2, piston 3, and piston rod 10 are prepared, and air is bled from the cylinder unit using conventional technology to ensure that there is no air inside the cylinder 2 or the first accumulator 21.

[0046] (2) Air discharge from gear motors and drain hoses Next, after connecting and assembling the motor unit and the cylinder unit, the first and second hydraulic couplers 63, 64 are set to the open mode, and the third hydraulic coupler 65 is set to the pressurized mode. As a result, hydraulic oil HF is pressurized into the drain passage of the housing 6, so that air in the gear motor 5 and the drain hose 61 is discharged into the accumulator chamber 23 of the first accumulator 21 and the communicating passage 4, and hydraulic oil HF and air in amounts approximately equal to the amount pressed in from the third hydraulic coupler 65 are discharged to the outside from the first and second hydraulic couplers 63, 64. In this case, because the first and second hydraulic couplers 63, 64 are arranged at the top of the vertical portions 4a, 4a of the communicating passage 4, air is not mixed into the first and second fluid chambers 2f, 2g from the communicating passage 4. Furthermore, the check valve 62 prevents air remaining in the second rod communicating hole 10d, the piston communicating hole 3a, the rod communicating hole 10c, the accumulator chamber 23 of the first accumulator 21, etc. from returning to the gear motor 5 or the drain hose 61. This ensures that no air is present in the gear motor 5 or the drain hose 61.

[0047] (3) Pressurizing hydraulic oil and air into the first accumulator Next, after all of the first to third hydraulic couplers 63-65 are set to the closed mode, one of the first and second hydraulic couplers 63, 64, for example, the first hydraulic coupler 63, is set to the pressurization mode. As a result, the pressure in both the first fluid chamber 2f and the second fluid chamber 2g increases due to the pressurized hydraulic oil HF, and the pressurized hydraulic oil HF is pressurized into the accumulator chamber 23 while compressing the set spring 25 of the first accumulator 21 through the orifice 27 of the second communication hole, the third communication hole, the piston communication hole 3a, the rod communication hole 10c, etc. As a result, with the set spring 25 fully compressed, the accumulator chamber 23 becomes filled with hydraulic oil HF containing air.

[0048] (4) Discharge of hydraulic oil and air from the first accumulator Thereafter, the first hydraulic coupler 63 is switched from the press-fit mode to the close mode, and the other hydraulic coupler, the second hydraulic coupler 64, is set to the open mode. As a result, the hydraulic oil HF in the accumulator chamber 23 together with air is discharged into the second fluid chamber 2g via the rod communicating hole 10c and the open-side check valve 26, and further discharged from the second hydraulic coupler 64 via the vertical portion 4a of the communicating passage 4. The above steps (3) and (4) may be repeated by reversing the press-fit mode and the open mode between the first and second hydraulic couplers 63, 64.

[0049] (5) Air discharge due to rotation of gear motor Next, one of the first and second hydraulic couplers 63, 64, for example the first hydraulic coupler 63, is set to the open mode, and the other, for example the second hydraulic coupler 64, is set to the pressurized mode. As a result, hydraulic oil HF is pressurized into the second fluid chamber 2g, causing the piston 3 to move toward the first fluid chamber 2f. After reaching the stroke end, the hydraulic oil HF flows through the communicating passage 4, causing the gear motor 5 to rotate. As a result, air in the communicating passage 4 and the gear motor 5 is discharged from the first hydraulic coupler 63 together with an amount of hydraulic oil HF equivalent to the amount pressurized. This operation may be repeated while reversing the setting of the open mode and the pressurized mode between the first and second hydraulic couplers 63, 64.

[0050] As described above, according to this embodiment, after assembling the mass damper 1A, the modes of the first to third hydraulic couplers 63 to 65 are switched while hydraulic oil HF is pressure-injected into the drain passage of the housing 6 via these hydraulic couplers. Air is then discharged along with the hydraulic oil HF from the gear motor 5, the drain passage, the drain hose 61, and the connecting passage 4, thereby effectively purging air from the hydraulic oil HF piping. As described above, the first to third hydraulic couplers 63 to 65 have the function of automatically opening and closing in response to the attachment and detachment of the hose-side couplers and the characteristic of minimizing the intrusion of air into the interior during installation. As a result, the piping of the mass damper 1A can be maintained air-free, thereby preventing the occurrence of cavitation and resulting problems during operation of the mass damper 1A.

[0051] Next, a mass damper 1B according to a second embodiment of the present invention will be described with reference to Fig. 2. In Fig. 2, components that are the same as or equivalent to those in the mass damper 1A of the first embodiment are given the same reference numerals. This also applies to Figs. 3 to 7, which show the other embodiments.

[0052] As is clear from a comparison with FIG. 1, the mass damper 1B differs from the mass damper 1A of the first embodiment in that the drain hose 61 is eliminated and the mass damper 1B is provided with a drain pipe 31 for discharging the hydraulic oil HF from the housing 6 and an accumulator for the drain pipe (hereinafter referred to as the "second accumulator") 41 for temporarily storing part of the pressure in the drain pipe 31.

[0053] The drain pipe 31 is formed in an inverted U shape and includes a horizontal pipe section 31a and left and right vertical pipe sections 31b, 31b extending downward from both ends of the horizontal pipe section 31a. The drain pipe 31 is connected to the drain passage of the housing 6 at the center of the horizontal pipe section 31a, and is connected to both ends of the communicating passage 4 (the connection between the vertical section 4a and the horizontal section 4b) at the lower ends of the vertical pipe sections 31b, 31b. Each vertical pipe section 31b is provided with a check valve 34 immediately above the connection with the communicating passage 4. The check valve 34 has a ball as a valve element and is configured to only allow the flow of hydraulic oil HF from the housing 6 side to the communicating passage 4 side.

[0054] In addition, as a configuration for bleeding air from the mass damper 1B, first and second hydraulic couplers 63, 64 are provided near the left and right ends of the horizontal section 4b of the connecting passage 4, and a third hydraulic coupler 65 is provided in the drain passage of the housing 6, as in the first embodiment.

[0055] The second accumulator 41 is provided in one of the vertical pipe sections 31b and arranged so as to protrude to the side thereof. The second accumulator 41 has a casing 42 that communicates with the vertical pipe section 31b, a piston 44 that is provided within the casing 42 so as to be able to slide horizontally and that defines a pressure accumulation chamber 43 within the casing 42, and a set spring 45 that biases the piston 44 toward the pressure accumulation chamber 43.

[0056] Furthermore, with the elimination of the drain hose 61, the second rod communicating hole 10d of the piston rod 10 to which the drain hose 61 was connected in the first embodiment has also been eliminated. As a result, the pressure accumulator chamber 23 of the first accumulator 21 communicates with the first and second fluid chambers 2f, 2g via the rod communicating hole 10c, the piston communicating hole 3a, and the check valve 26. The rest of the configuration of the mass damper 1B is the same as that of the mass damper 1A of the first embodiment.

[0057] With the above configuration, when the pressure inside the housing 6 increases due to prolonged operation of the mass damper 1B and the gear motor 5, and becomes greater than the pressure of the lower-pressure one of the first and second fluid chambers 2f, 2g, the check valve 34 on that side opens. This causes a portion of the hydraulic oil HF inside the housing 6 to be discharged to the first or second fluid chamber 2f, 2g via the drain passage, the horizontal pipe section 31a and vertical pipe section 31b of the drain piping 31, and the vertical section 4a of the communication passage 4. As a result, the pressure inside the housing 6 is released to the first or second fluid chamber 2f, 2g, preventing the pressure inside the housing 6 from increasing.

[0058] Furthermore, in the above-described situation, when the pressure of the hydraulic oil HF upstream of the check valve 34 in the drain pipe 31 does not decrease significantly due to a delayed response or leakage from the check valve 34, or an increase in pressure on the communicating passage 4 and cylinder 2 (fluid chamber) side, the hydraulic oil HF flows from the drain pipe 31 into the accumulator chamber 43 of the second accumulator 41 and compresses the set spring 45 via the piston 44. As a result, a portion of the pressure of the hydraulic oil HF is stored in the second accumulator 41, and an increase in pressure inside the housing 6 is reliably prevented.

[0059] Furthermore, in the mass damper 1B of this embodiment, as in the first embodiment, after assembly, air can be bled from the piping for the hydraulic oil HF by setting the modes of the first to third hydraulic couplers 63 to 65. Air bleed is performed, for example, in the following procedure.

[0060] (1) Bleeding air from the cylinder unit A motor unit assembled from the connecting passage 4, drain pipe 31, gear motor 5, and second accumulator 41, and a cylinder unit assembled from the cylinder 2, piston 3, and piston rod 10 are prepared, and air is bled from the cylinder unit using conventional technology to ensure that no air is present inside the cylinder 2 or the first accumulator 21.

[0061] (2) Air discharge from gear motors and drain hoses Next, after connecting and assembling the motor unit and the cylinder unit, the first and second hydraulic couplers 63, 64 are set to the open mode, and the third hydraulic coupler 65 is set to the pressurized mode. As a result, hydraulic oil HF is pressurized into the drain passage of the housing 6, and air in the gear motor 5, drain pipe 31, and second accumulator 41 is discharged into the communicating passage 4 via the open left and right check valves 34, and hydraulic oil HF and air in amounts approximately equal to the amount pressurized from the third hydraulic coupler 65 are discharged to the outside from the first and second hydraulic couplers 63, 64. In this case, because the first and second hydraulic couplers 63, 64 are arranged near the connection between the vertical sections 4a, 4a and the horizontal section 4b of the communicating passage 4, air is not mixed into the first and second fluid chambers 2f, 2g from the communicating passage 4.

[0062] (3) Air discharge due to rotation of gear motor Next, while maintaining the third hydraulic coupler 65 in the closed mode, one of the first and second hydraulic couplers 63, 64, for example the first hydraulic coupler 63, is set to the open mode, and the other, for example the second hydraulic coupler 64, is set to the pressurized mode. As a result, hydraulic oil HF is pressurized into the second fluid chamber 2g, causing the piston 3 to move toward the first fluid chamber 2f. After reaching the stroke end, the hydraulic oil HF flows through the communicating passage 4, causing the gear motor 5 to rotate. As a result, air in the communicating passage 4 and the gear motor 5 is discharged from the first hydraulic coupler 63 together with an amount of hydraulic oil HF approximately equal to the amount pressurized. This operation may be repeated while reversing the setting of the open mode and the pressurized mode between the first and second hydraulic couplers 63, 64.

[0063] As described above, in this embodiment, as in the first embodiment, when assembling the mass damper 1B, the modes of the first to third hydraulic couplers 63 to 65 are switched, and the hydraulic oil HF is pressurized into the drain passage of the housing 6 via these hydraulic couplers 63 to 65, and air is discharged together with the hydraulic oil HF from the gear motor 5, the drain passage, and the connecting passage 4, thereby effectively bleeding air from the piping for the hydraulic oil HF, etc.

[0064] Next, a mass damper 1C according to a third embodiment of the present invention will be described with reference to Fig. 3. As is clear from a comparison with Fig. 2, the mass damper 1C differs from the mass damper 1B of the second embodiment in that the first to third hydraulic couplers 63 to 65 are eliminated, the second accumulator 41 for the drain piping is disposed in the horizontal pipe section 31a rather than the vertical pipe section 31b, and the horizontal pipe section 31a and the vertical pipe sections 31b, 31b are joined via a pipe joint tee 32.

[0065] Each pipe coupling tee 32 has a first pipe section 32a and a second pipe section 32b that extend coaxially with each other, and a third pipe section 32c that extends at a right angle between the first and second pipe sections 32a, 32b. A tapered screw hole (not shown) is formed in the upper first pipe section 32a, the lower second pipe section 32b is connected to the upper end of the vertical pipe section 31b of the drain pipe 31, and the third pipe section 32c is connected to the end of the horizontal pipe section 31a. A tapered screw is screwed into the screw hole of the first pipe section 32a from above, and these screw hole and screw form a tapered plug 33 for the drain pipe.

[0066] The check valves 34 are provided in each vertical pipe section 31b and are arranged immediately below the second pipe section 32b of the pipe joint tee 32. The check valves 34 have a ball as a valve element and are configured to allow only the flow of hydraulic oil HF from the housing 6 side to the communicating passage 4 side.

[0067] The second accumulator 41 is provided in the horizontal pipe portion 31a and arranged to protrude upward therefrom. The second accumulator 41 has a casing 42 that communicates with the horizontal pipe portion 31a, a piston 44 that is arranged within the casing 42 so as to be able to slide vertically and define a pressure accumulation chamber 43 at the bottom of the casing 42, and a set spring 45 that biases the piston 44 toward the pressure accumulation chamber 43.

[0068] A tapered screw hole (not shown) that penetrates vertically is formed in the piston 44. A tapered screw is screwed into this screw hole from above, and the screw hole and screw form a tapered plug 46 for the second accumulator.

[0069] The basic operation of the mass damper 1C of this embodiment is the same as that of the mass damper 1B of the second embodiment. For example, when the pressure inside the housing 6 increases due to prolonged operation of the mass damper 1C and the gear motor 5, the check valve 34 on the lower pressure side of the first or second fluid chamber 2f, 2g opens, causing a portion of the hydraulic oil HF inside the housing 6 to be discharged into the first or second fluid chamber 2f, 2g, thereby preventing an increase in pressure inside the housing 6. Furthermore, when the pressure of the hydraulic oil HF upstream of the check valve 34 in the drain pipe 31 does not decrease significantly, the hydraulic oil HF flows from the horizontal pipe portion 31a into the accumulator chamber 43 of the second accumulator 41, causing a portion of the pressure of the hydraulic oil HF to be accumulated in the second accumulator 41, thereby reliably preventing an increase in pressure inside the housing 6.

[0070] Furthermore, with the mass damper 1C of this embodiment, air can be bled from the piping for the hydraulic oil HF by operating the tapered plug 33 and check valve 34 for the drain piping. Specifically, for example, after the assembly work of the mass damper 1C (assembly of components and injection of hydraulic oil HF) is completed, the tapered plug 33 is filled with hydraulic oil HF and the screws of the tapered plug 33 are removed. As a result, air that has collected from the housing 6, the drain passage, and the like and is present in the horizontal pipe portion 31a of the drain piping 31 is guided above the tapered plug 33 and discharged to the outside.

[0071] Furthermore, with the tapered plug 33 removed, the ball of the check valve 34 is manually pushed down to open it. As a result, air that has collected from the first and second fluid chambers 2f, 2g and the communicating passage 4 and is present below the check valve 34 in the vertical pipe section 31b is guided above the check valve 34 and discharged to the outside via the tapered plug 33. By operating the tapered plug 33 and the check valve 34 in the above manner, air can be easily and reliably discharged from the piping for the hydraulic oil HF after the assembly work of the mass damper 1C is completed.

[0072] Thereafter, when the tapered plug 33 is tightened, the high airtightness of the tapered plug 33 prevents air from entering from the outside through the tapered plug 33. As a result, the piping of the mass damper 1C can be kept air-free, and therefore the occurrence of cavitation and the resulting defects during operation of the mass damper 1C can be prevented.

[0073] Furthermore, by loosening the tapered plug 46 of the second accumulator 41, the air present in the pressure accumulation chamber 43 of the second accumulator 41 can be guided above the piston 44 via the tapered plug 46 located above it, and can be easily discharged.

[0074] Next, a mass damper 1D according to a fourth embodiment of the present invention will be described with reference to Fig. 4. As is clear from a comparison with Fig. 3, the mass damper 1D differs from the mass damper 1C of the third embodiment in that the second accumulator 41 for the drain pipe is provided between the pipe coupling tee 32 and the check valve 34 in one of the vertical pipe sections 31b rather than in the horizontal pipe section 31a, and in that a tapered plug is not provided on the piston 44 of the second accumulator 41. The second accumulator 41 is attached to the vertical pipe section 31b with the accumulator chamber 43 communicating with the vertical pipe section 31b and the piston 44 and set spring 45 aligned horizontally.

[0075] According to this configuration, as in the third embodiment, for example, after the assembly of the mass damper 1D is completed, the tapered plug 33 is filled with hydraulic oil HF, and by removing the screws of the tapered plug 33 and pushing down the ball of the check valve 34, air can be easily and reliably discharged from the horizontal pipe portion 31a and the vertical pipe portion 31b of the drain piping 31. Furthermore, by operating the tapered plug 33 and the check valve 34 in this manner, air present in the accumulator chamber 43 of the second accumulator 41 is efficiently discharged to the outside via the upper tapered plug 33.

[0076] Next, a mass damper 1E according to a fifth embodiment of the present invention will be described with reference to Fig. 5. As is clear from a comparison with Fig. 3, the mass damper 1E differs from the mass damper 1C of the third embodiment in the arrangement of the drain pipe and tapered plug 33, the absence of a second accumulator 41, and the provision of a check valve 72 for air bleeding in the communication passage 4. The drain pipe 71 of this embodiment is located on one upper side of the housing 6 and has a short horizontal pipe portion 71a and a hose portion 71b, with the two portions 71a and 71b joined to each other by a pipe joint tee 32.

[0077] One end of the horizontal pipe section 71a is connected to the drain passage of the housing 6, protrudes horizontally to one side from the housing 6, and the other end is connected to the third pipe section 32c of the pipe joint tee 32. A tapered plug 33 is provided in the first pipe section 32a of the pipe joint tee 32, and the second pipe section 32b is connected to one end of the hose section 71b.

[0078] The hose portion 71b is flexible and is attached in a loose state between the second pipe portion 32b of the pipe joint tee 32 and the first rod portion 10a of the piston rod 10. The other end of the hose portion 71b is connected to a second rod communicating hole 10d formed in the first rod portion 10a. The second rod communicating hole 10d opens at one end to the outer circumferential surface of the first rod portion 10a, extends coaxially with the first rod portion 10a, and communicates with the piston communicating hole 3a at the other end. A check valve 34 is provided in the hose portion 71b directly below the second pipe portion 32b of the pipe joint tee 32.

[0079] In addition, check valves 72, 72 for bleeding air are provided at the top of both ends of the communication passage 4. The check valves 72 only allow fluid to flow from the top to the bottom, and are configured to open when the ball is manually pushed from above.

[0080] In this configuration, when the pressure inside the housing 6 increases and becomes greater than the pressure in the accumulator chamber 23 of the first accumulator 21, the check valve 34 opens. As a result, a portion of the hydraulic oil HF inside the housing 6 is discharged to the accumulator chamber 23 of the first accumulator 21 via the drain passage, the horizontal pipe portion 71a and hose portion 71b of the drain pipe 71, the second rod communicating hole 10d, the piston communicating hole 3a, and the rod communicating hole 10c. As a result, the pressure inside the housing 6 is released to the first accumulator 21, preventing the pressure inside the housing 6 from increasing.

[0081] In this case, due to the function of the first accumulator 21, the pressure in the accumulator chamber 23 is maintained at a low pressure that is significantly lower than the pressure in the first or second fluid chamber 2f, 2g on the high-pressure side, which increases with the movement of the piston 3. Therefore, the pressure acting on the drain pipe 71 and the check valve 34 is significantly smaller than in the mass damper 1C of the third embodiment, in which the drain pipe 31 is connected to the first and second fluid chambers 2f, 2g and the check valve 34 is disposed in the drain pipe 31. As a result, there are advantages in that the risk of leakage of the hydraulic oil HF from the connection portion of the drain pipe 71 is reduced and an inexpensive check valve with low pressure resistance can be used.

[0082] Furthermore, during operation of the mass damper 1E, the flexible hose portion 71b of the drain pipe 71 follows the piston rod 10 well, so that even if the pipe is repeatedly pushed and pulled, problems such as damage due to bending and leakage of the hydraulic oil HF are reliably prevented.

[0083] Furthermore, for example, after completing the assembly of the mass damper 1E, by performing the same operations as in the third embodiment on the tapered plug 33 and the check valve 34, it is possible to easily and reliably discharge air from the horizontal pipe portion 71a and hose portion 71b of the drain piping 71. Furthermore, by manually pushing down the ball of the check valve 72, it is possible to discharge air that has collected from the first and second fluid chambers 2f, 2g, the communicating passage 4, and is present below the check valve 72.

[0084] Next, a mass damper 1F according to a sixth embodiment of the present invention will be described with reference to Fig. 6. As is clear from a comparison with Fig. 3, the mass damper 1F differs from the mass damper 1C of the third embodiment in that the drain pipe 31 is provided only on one side (the right side in the figure) of the housing 6 and the second accumulator 41, and that a check valve 72 for bleeding air is provided in the communication passage 4, as in the fifth embodiment.

[0085] In this embodiment, the horizontal pipe section 31a of the drain pipe 31 extends horizontally to one side from between the housing 6 and the second accumulator 41, and the vertical pipe section 31b extends downward from near the end of the horizontal pipe section 31a, and the two pipe sections 31a, 31b are joined to each other by a pipe joint tee 32. The lower end of the vertical pipe section 31b is connected to a hydraulic oil fill hole 51 formed in the rod fitting section 2d of the cylinder 2. A check valve 34 is provided near the inlet of the hydraulic oil fill hole 51 and also serves to prevent backflow when hydraulic oil HF is filled into the second fluid chamber 2g. The check valves 72 for bleeding air are configured in the same way as in the fifth embodiment and are located at the top of both ends of the communication passage 4.

[0086] In this configuration, when the pressure inside the housing 6 increases and becomes greater than the pressure in the second fluid chamber 2g, the check valve 34 opens, causing a portion of the hydraulic oil HF inside the housing 6 to be discharged into the second fluid chamber 2g through the drain passage, the horizontal pipe section 31a and the vertical pipe section 31b of the drain piping 31, and the hydraulic oil injection hole 51. This allows the pressure inside the housing 6 to be released into the second fluid chamber 2g, preventing the pressure inside the housing 6 from increasing.

[0087] Furthermore, for example, after completing the assembly of the mass damper 1F, the tapered plug 33 can be filled with hydraulic oil HF and then loosened to easily and reliably discharge air present in the horizontal pipe portion 31a and the vertical pipe portion 31b of the drain pipe 31. Furthermore, by loosening the tapered plug 46 of the second accumulator 41, the air present in the accumulator chamber 43 of the second accumulator 41 can be guided above the piston 44 via the tapered plug 46 and discharged. Furthermore, by manually pushing down the ball of the check valve 72, air that has collected from the first and second fluid chambers 2f, 2g, the communicating passage 4, and is present below the check valve 72 can be discharged.

[0088] Next, a mass damper 1G according to a seventh embodiment of the present invention will be described with reference to Fig. 7. As is clear from a comparison with Fig. 3, the mass damper 1G differs from the mass damper 1C of the third embodiment in the destination to which the vertical pipe sections 31b, 31b of the drain pipe 31 are connected.

[0089] Specifically, one vertical pipe section 31b (left side in FIG. 7) is connected to the apex of one end of the communicating passage 4, and the check valve 34 is disposed in a position immediately below the pipe joint tee 32 of the vertical pipe section 31b. The other vertical pipe section 31b (right side in FIG. 7) is connected to the hydraulic oil fill hole 51 of the rod fitting section 2d, as in the sixth embodiment, and the check valve 34 is disposed near the inlet of the hydraulic oil fill hole 51. In addition, a check valve 72 for bleeding air is disposed at the apex of the other end of the communicating passage 4.

[0090] According to this configuration, for example, after completing the assembly of the mass damper 1G, for the left vertical pipe portion 31b, air can be easily and reliably discharged from the horizontal pipe portion 31a and the vertical pipe portion 31b by performing the same operations as in the third embodiment on the tapered plug 33 and the check valve 34. For the right vertical pipe portion 31b, air can be discharged from the horizontal pipe portion 31a and the vertical pipe portion 31b by loosening the tapered plug 33. Furthermore, as in the sixth embodiment, air present in the accumulator chamber 43 can be discharged upward by loosening the tapered plug 46 of the second accumulator 41, and air present in the communicating passage 4 can be discharged by manually pressing down the ball of the check valve 72.

[0091] The present invention is not limited to the embodiments described above and can be implemented in various ways. For example, the first and second embodiments show specific air bleeding methods that involve switching the modes of the first to third hydraulic couplers 63 to 65. These methods are merely examples, and may, of course, be modified to suit the configuration of the mass damper within the spirit and scope of the present invention.

[0092] In addition, in the embodiments other than the first and fifth embodiments, the second accumulator 41 for the drain pipe is provided to deal with a pressure rise in the drain pipe 31 due to a delayed response or leakage of the check valve 34. However, the present invention is not limited to this, and if the possibility of such a pressure rise is low, the second accumulator 41 may be omitted.

[0093] Furthermore, in the sixth and seventh embodiments, the check valve 34 is disposed in the hydraulic oil fill hole 51 so as to also function as a check valve for preventing backflow of the injected hydraulic oil HF, but in addition to this check valve 34, a manually opened check valve may be provided in the vertical pipe section 31b immediately below the pipe coupling tee 32. Furthermore, in the first, second and fifth embodiments, the first and second hydraulic couplers 63, 64 and the check valve 72 are used to inject hydraulic oil HF and to put a certain pressure into the first accumulator 21, so it goes without saying that the hydraulic oil fill hole 51 and the check valve 52 may be omitted.

[0094] Furthermore, in the embodiment, a gear motor is used as the pressure motor, but other types of pressure motors, such as a piston motor, a vane motor, or a screw motor, may also be used. Also, in the embodiment, normal hydraulic oil HF is used as the working fluid for the damper, but it goes without saying that other appropriate working fluids may also be used. In addition, the detailed configuration can be changed as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0095] 1A Mass damper according to the first embodiment 1B Mass damper according to the second embodiment 1C Mass damper according to the third embodiment 1D Mass damper according to the fourth embodiment 1E Mass damper according to the fifth embodiment 1F Mass damper according to the sixth embodiment 1G Mass damper according to the seventh embodiment 2 cylinders 2f 1st fluid chamber (discharge part) 2g 2nd fluid chamber (discharge part) 3 pistons 4 passages 4a Vertical section 4b Horizontal part 5 Gear motor (pressure motor) 6. Housing 8 Output shaft (rotating body) 9 Flywheel (rotating mass) 23 Accumulator chamber (discharge section) of first accumulator 31 Drain piping 31a Horizontal pipe section (housing side passage section) 31b Vertical pipe section (discharge side passage section) 32 Pipe fitting tee 32a 1st pipe section 32b 2nd pipe section 32c 3rd pipe section 33 Tapered plug 34 Check valve 41 Second accumulator (accumulator) 42 Casing 43 Pressure accumulator 44 Piston 45 sets of springs 46 Tapered plug for accumulator 61 Drain hose (drain piping) 62 Check valve for air bleeding 63 First hydraulic coupler 64 Second hydraulic coupler 65 3rd hydraulic coupler 71 Drain piping 71a Horizontal pipe section (housing side passage section) 71b Hose section (discharge section side passage section) 72 Check valve for air bleeding HF hydraulic oil (working fluid)

Claims

1. a cylinder filled with a working fluid; a piston slidably disposed within the cylinder, the piston dividing the interior of the cylinder into a first fluid chamber and a second fluid chamber; a communication passage that bypasses the piston and communicates with the first and second fluid chambers; a pressure motor having a housing which is in communication with the communication passage and has a drain passage for discharging the working fluid, and a rotor housed in the housing, and which converts the pressure of the working fluid flowing through the communication passage as the piston slides into rotational motion of the rotor; a rotating mass that exhibits a vibration suppression effect by being rotationally driven by the pressure motor; a drain pipe having one end connected to the drain passage of the housing and the other end communicating with a discharge portion through which the working fluid is discharged; a first hydraulic coupler and a second hydraulic coupler provided on both sides of the housing in the communication passage, and a third hydraulic coupler provided in the drain passage, a pressure motor-using mass damper configured to discharge air from within the pressure motor and the drain pipe into the communication passage by setting the first and second hydraulic couplers to an open mode and setting the third hydraulic coupler to a press-in mode in which a hydraulic fluid is pressurized, and then to discharge air from within the communication passage to the outside from the open one of the first and second hydraulic couplers by setting one of the first and second hydraulic couplers to the open mode, the other of the first and second hydraulic couplers to the press-in mode, and the third hydraulic coupler to a closed mode.

2. 2. The mass damper using a pressure motor according to claim 1, wherein the communication passage has a pair of vertical portions that communicate with the first and second fluid chambers, respectively, and a horizontal portion connected between upper ends of the pair of vertical portions, and the first and second hydraulic couplers are respectively disposed near connections between the vertical portions and the horizontal portions.

3. a cylinder filled with a working fluid; a piston slidably disposed within the cylinder, the piston dividing the interior of the cylinder into a first fluid chamber and a second fluid chamber; a communication passage that bypasses the piston and communicates with the first and second fluid chambers; a pressure motor having a housing which is in communication with the communication passage and has a drain passage for discharging the working fluid, and a rotor housed in the housing, and which converts the pressure of the working fluid flowing through the communication passage as the piston slides into rotational motion of the rotor; a rotating mass that exhibits a vibration suppression effect by being rotationally driven by the pressure motor; a drain pipe including: a housing-side passage portion connected to the drain passage of the housing and extending horizontally; and a discharge-portion-side passage portion extending downward from near an end of the housing-side passage portion and communicating with a discharge portion from which the working fluid is discharged; a pipe coupling tee having a first pipe portion and a second pipe portion extending coaxially with each other, and a third pipe portion extending perpendicularly from between the first and second pipe portions, wherein a tapered screw hole is formed in the first pipe portion, the second pipe portion is connected to an upper end of the discharge portion side pipe line portion of the drain pipe, and the third pipe portion is connected to an end of the housing side pipe line portion; a tapered plug having tapered threads screwed into the threaded hole of the first pipe portion; a check valve provided in the discharge portion-side passage portion of the drain pipe, the check valve allowing only the flow of working fluid from the housing side to the discharge portion side; A mass damper using a pressure motor, comprising:

4. 4. The mass damper using a pressure motor according to claim 3, wherein the check valve has a valve body, and is configured so that air present below the check valve is discharged upward by pushing down the valve body with the tapered plug removed.

5. an accumulator disposed above the housing-side passage portion of the drain pipe for storing a portion of the pressure of the working fluid in the drain pipe; the accumulator includes a casing communicating with the housing-side passage portion, a piston slidably disposed in the casing in a vertical direction and defining a pressure accumulator chamber in a lower portion of the casing, and a set spring biasing the piston toward the pressure accumulator chamber, 5. The mass damper using a pressure motor according to claim 3 or 4, further comprising an accumulator tapered plug having a tapered screw hole formed to penetrate the piston in the up-down direction, and a tapered screw screwed into the screw hole from above.

6. 5. The mass damper using a pressure motor according to claim 3, further comprising an air vent check valve provided at a top of the communication passage, the check valve discharging air present in the communication passage when a valve body is pressed down.

Images