Variable cross-section hydraulic fluid inerter device and system and inerter coefficient adjusting method

Abstract

The invention relates to a variable cross-section hydraulic fluid inerter device and an inerter coefficient adjusting method.The variable cross-section hydraulic fluid inerter device comprises a piston rod, a first piston fixedly connected to the piston rod, a variable cross-section hydraulic cylinder and a second piston, the variable cross-section hydraulic cylinder is of a sleeve structure internally provided with an annular protrusion, and a first cavity is formed in the inner side of the annular protrusion; the outer side of the annular protrusion forms a second cavity in the variable-section hydraulic cylinder, the first piston is matched with the first cavity, the second piston is matched with the second cavity, and the piston rod penetrates through the second piston. Compared with the prior art, the piston rod pushes the pistons with different sections in different strokes, so that controllable change and accurate control of the inerter coefficient along with the strokes are realized, the structure is simple and compact, and the operation is stable.

Description

Technical Field

[0001] The present invention relates to the field of high-end equipment manufacturing, and particularly to a variable cross-section hydraulic fluid inertance device, system and inertance coefficient adjustment method. Background Art

[0002] Currently, a variety of fluid inertance devices have been developed, such as a fluid inertance container with a piston rod inside, a double-cylinder fluid inertance device, a passive frequency adaptive fluid inertance device, etc. Most of these fluid inertance devices are only innovative in working forms and fail to achieve variable inertance coefficients of the fluid inertance container, so they have fewer applicable occasions. Among them, a passive frequency adaptive fluid inertance device only realizes the adaptive change based on frequency and fails to achieve variable inertance coefficients based on stroke. In actual use, for example, when installed between layers in a frame structure, an inertance container with a variable inertance coefficient based on stroke often has a greater application prospect. For a variable cross-section fluid inertance device, its inertance coefficient is variable based on stroke, and the inertance coefficients of each stage can be adjusted by flexibly adjusting the area of the piston, which can adapt to various shock absorption occasions.

[0003] Application CN118208519A discloses an adjustable multi-spiral tube fluid inertance container, which changes the pitch of the spiral tube through the linear and rotational motion of the lead screw and the lead screw nut, so as to achieve adjustable inertance coefficient within a certain range. The pitch changes with the relative motion relationship between the lead screw nut, making it difficult to accurately adjust the inertance coefficient and unable to achieve the device obtaining the required inertance coefficient according to the stroke. At the same time, the device has a complex structure and is difficult to manufacture. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defect that the inertance coefficient cannot be quantitatively adjusted with the stroke in the above-mentioned existing technologies, and to provide a variable cross-section hydraulic fluid inertance device, system and inertance coefficient adjustment method.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The present invention provides a variable cross-section hydraulic fluid inertance device, including a piston rod and a first piston, the first piston is fixedly connected to the piston rod, and is characterized in that it further includes a variable cross-section hydraulic cylinder and a second piston; the variable cross-section hydraulic cylinder is a sleeve structure with an annular protrusion inside, a first cavity is formed inside the annular protrusion, a second cavity is formed outside the annular protrusion in the variable cross-section hydraulic cylinder, the first piston is matched with the first cavity, the second piston is matched with the second cavity, and the piston rod passes through the second piston.

[0007] Furthermore, the cross-sectional area of the first piston is smaller than that of the second piston.

[0008] Furthermore, the cross-section of the first piston matches the shape and size of the cross-section of the first cavity of the variable cross-section hydraulic cylinder, and the cross-section of the second piston matches the shape and size of the cross-section of the second cavity of the variable cross-section hydraulic cylinder.

[0009] Further, the number of the second pistons is two, which are arranged on both sides of the first piston, and the number of the second cavities is two, which are respectively located on both sides of the first cavity.

[0010] Furthermore, the internal cavity of the variable cross-section hydraulic cylinder is in a dumbbell shape with larger ends and smaller middle, the shapes of the first cavity and the two second cavities are both cylinders, and the bottom diameter of the cylinder of the second cavity at both ends is larger than the bottom diameter of the cylinder of the first cavity in the middle.

[0011] Furthermore, it further includes permanent magnets, which include a first permanent magnet group and a second permanent magnet group. The first permanent magnet group includes a first left permanent magnet and a first right permanent magnet. The first left permanent magnet is installed on the left side of the left second cavity, and the first right permanent magnet is installed on the left side of the left second piston. The second permanent magnet group includes a second left permanent magnet and a second right permanent magnet. The second left permanent magnet is installed on the right side of the right second piston, and the second right permanent magnet is installed on the right side of the right second cavity. The first left permanent magnet and the first right permanent magnet are mutually repulsive in magnetic poles, and the second left permanent magnet and the second right permanent magnet are mutually repulsive in magnetic poles. When the piston rod moves in the direction away from the bottom of the second cavity of the variable cross-section hydraulic cylinder, the second piston is reset under the action of the permanent magnets.

[0012] Further, it further includes a connecting piece, and the connecting piece is connected to the structure that needs shock absorption.

[0013] Further, it further includes a first oil port, a second oil port and a spiral tube. The first oil port and the second oil port are located on different sides of the first piston, and the first oil port and the second oil port are connected by a spiral tube arranged outside the variable cross-section hydraulic cylinder.

[0014] Furthermore, the hydraulic system includes a variable cross-section hydraulic fluid inertia device.

[0015] According to another aspect of the present invention, there is provided an inertia coefficient adjustment method, including the following steps:

[0016] Obtain the inertia coefficient requirement of the application scenario to be applied, adjust the movement stroke of the piston rod, and calculate the inertia coefficient of the variable cross-section hydraulic fluid inertia device until the inertia coefficient requirement is met;

[0017] The calculation expression of the inertia coefficient of the variable cross-section hydraulic fluid inertia device is

[0018]

[0019] In the formula, m inis the inertia coefficient, x is the movement stroke of the piston rod, x 1 is the movement stroke of the piston rod when the first piston 4 contacts the second piston, x 2 is the one-way maximum stroke of the piston rod (2), A 1 is the working area of the first piston 4, A 2 is the working area of the second piston 6, A 3 is the cross-sectional area of the solenoid tube 7, r 1 is the radius of the solenoid tube 7, h is the pitch of the solenoid tube 7, l is the length of the solenoid tube 7, and ρ is the density of the liquid in the hydraulic cylinder.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The present invention provides a movable second piston outside the first piston. When the first piston does not contact the second piston, the inertia coefficient of the device is related to the cross-sectional area of the first piston. When the piston rod axially moves under the action of an external driving force until the first piston contacts the second piston, the piston rod continues to move and pushes the second piston to move in the second cavity of the variable cross-section hydraulic cylinder. Since the cross-sectional area of the second piston is larger than that of the first piston, the inertia coefficient changes at this time, and its value is related to the cross-sectional area of the second piston. By pushing pistons with different cross-sections at different strokes of the piston rod, a controllable change of the inertia coefficient with the stroke is achieved, which can adapt to various shock-absorbing scenarios.

[0022] 2. The present invention conducts a theoretical analysis on the structural characteristics of the variable cross-section hydraulic fluid inertia device, and obtains the calculation formula of the inertia coefficient at different strokes, so that the movement stroke of the piston rod can be quickly adjusted according to the inertia coefficient requirements of the application scenario.

[0023] 3. The inertia coefficient of each stage can be easily adjusted by replacing the sizes of the two pistons, and it has high flexibility in practical applications.

[0024] 4. Both the second piston and the second cavity of the variable cross-section hydraulic cylinder are arranged bidirectionally, which improves the operation stability of the inertia device and facilitates the installation and use of the inertia device.

[0025] 5. The mechanical form of the present invention is simple and easy to implement, and can meet the installation requirements of narrow or special spaces. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of a variable cross-section hydraulic fluid inertia device;

[0027] In the figure, 1. Connecting piece, 2. Piston rod, 3. First oil port, 4. First piston, 5. Variable cross-section hydraulic cylinder, 501. First cavity of the hydraulic cylinder, 502. Second cavity of the hydraulic cylinder, 6. Second piston, 7. Solenoid tube, 8. Permanent magnet, 9. Second oil port. Detailed implementation manners

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] As shown in Figure 1 , the present invention relates to a variable cross-section hydraulic fluid inertance device, including a connecting member 1, a piston rod 2, a first oil port 3, a first piston 4, a variable cross-section hydraulic cylinder 5, a second piston 6, a spiral tube 7, a permanent magnet 8, and a second oil port 9. The connecting member 1 is connected to the structure that needs to be shock-absorbed. The piston rod 2 is fixedly connected to the first piston 4. The first piston 4 is installed in the first cavity 501 of the variable cross-section hydraulic cylinder 5. The first oil port 3 and the second oil port 9 are opened in the variable cross-section hydraulic cylinder 5. The first oil port 3 and the second oil port 9 are located on the opposite sides of the first piston 4. The first oil port 3 and the second oil port 9 are connected by a spiral tube 7 arranged outside the variable cross-section hydraulic cylinder 5. The second piston 6 is installed in the second cavity 502 of the variable cross-section hydraulic cylinder 5. When the piston rod 2 axially moves to a certain extent under the action of an external driving force, the first piston 4 will contact the second piston 6. At this time, the two can be regarded as the same sealed piston, and the cross-sectional area is the area of the second piston 6. When the piston rod 2 continues to move, it will push the second piston 6 to move in the second cavity 502 of the variable cross-section hydraulic cylinder 5. The permanent magnets 8 are respectively installed on the side of the second piston 6 opposite to the bottom of the variable cross-section hydraulic cylinder 5 and the bottom of the second cavity 502 of the variable cross-section hydraulic cylinder 5.

[0030] The piston rod 2 axially moves under the action of an external driving force, driving the first piston 4 to slide inside the first cavity 501 of the variable cross-section hydraulic cylinder 5, so that the liquid in the variable cross-section hydraulic cylinder 5 enters and exits the spiral tube 7 through the first oil port 3 and the second oil port 9, thereby simulating the mechanical behavior of inertance; when the piston rod 2 moves to a certain stroke, the first piston 4 will contact the second piston 6. At this time, the two can be regarded as the same sealed piston, and the cross-sectional area is the area of the second piston 6. When the piston rod 2 continues to move, it will push the second piston 6 to move in the second cavity 502 of the variable cross-section hydraulic cylinder 5. At this time, the inertance coefficient of the fluid inertance container increases. When the piston rod 2 moves in the reverse direction, the second piston 6 will be reset under the action of the permanent magnet 8.

[0031] As a preferred technical solution, the cross-section of the first piston is circular, the cross-section of the second piston is an annular shape with a hole in the center, the cross-sectional radius of the first piston is smaller than the outer edge radius of the cross-section of the second piston, and the piston rod passes through the inner hole of the second piston.

[0032] The inertia coefficient derivation of the variable cross-section hydraulic fluid inertance device proposed by the present invention is as follows:

[0033] As Figure 1 shown, assume that the working area of the first piston 4 is A 1 , and the working area of the second piston 6 is A 2 , the cross-sectional area of the spiral tube 7 is A 3 , the radius is r 1 , the pitch is h, the length is l, the density of the liquid in the hydraulic cylinder is ρ, and when the piston rod 2 moves from the central position to the right by x 1 , the first piston 4 contacts the second piston 6, and the one-way maximum stroke of the piston rod 2 is x 2 .

[0034] During the analysis process, it is assumed that the piston is completely sealed, the liquid in the hydraulic cylinder completely flows into the spiral tube, and the fluid is incompressible.

[0035] When the stroke of the piston rod 2 from the central position to the right is 0 to x 1 :

[0036] The dynamic model of the fluid in the first hydraulic cylinder passing through the spiral tube can be expressed as:

[0037]

[0038] In the formula: F 1 is the force applied to the first screw rod, m in1 is the inertia coefficient, and x is the relative displacement of the first piston 4 relative to the variable cross-section hydraulic cylinder 5.

[0039] The mass m 1 of the fluid in the spiral tube 7 can be expressed as:

[0040] m 1 = ρA 3 l (2)

[0041] When the stroke of the piston rod 2 is x, according to the principle of fluid volume conservation, we can obtain:

[0042]

[0043] In the formula: h is the pitch of the spiral tube, r 1 is the spiral radius of the slender spiral tube, and θ is the corresponding rotation angle of the fluid entering the spiral tube.

[0044] The rotational inertia J generated by the fluid rotating in the spiral tube is:

[0045]

[0046] According to the law of conservation of energy, we can obtain:

[0047]

[0048] Substituting equations (2), (3), and (4) into equation (5) gives the inertia capacitance coefficient m in1 as:

[0049]

[0050] The stroke of the piston rod 2 moving to the right is x 1 ~x 2 when:

[0051] At this time, the second piston 6 starts to work, and the generated inertia capacitance coefficient can be obtained according to the above derivation as:

[0052]

[0053] In summary, the inertia capacitance coefficient m of this device in The formula is:

[0054]

[0055] where x is the stroke of the piston rod moving to the right from the central position.

[0056] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A variable cross-section hydraulic fluid inertia device, comprising a piston rod (2) and a first piston (4), wherein the first piston (4) is fixedly connected to the piston rod (2), characterized in that: It also includes a variable-section hydraulic cylinder (5) and a second piston (6); the variable-section hydraulic cylinder (5) is a sleeve structure with an annular protrusion inside, the inner side of the annular protrusion forms a first cavity (501), and the outer side of the annular protrusion forms a second cavity (502) in the variable-section hydraulic cylinder (5); the first piston (4) cooperates with the first cavity (501), the second piston (6) cooperates with the second cavity (502), and the piston rod (2) passes through the second piston (6).

2. A variable cross-section hydraulic fluid inertia device according to claim 1, characterized in that: The cross-sectional area of ​​the first piston (4) is smaller than the cross-sectional area of ​​the second piston (6).

3. A variable cross-section hydraulic fluid inertia device according to claim 2, characterized in that: The cross-section of the first piston (4) matches the cross-section shape and size of the first cavity (501) of the variable-section hydraulic cylinder (5), and the cross-section of the second piston (6) matches the cross-section shape and size of the second cavity (502) of the variable-section hydraulic cylinder (5).

4. A variable cross-section hydraulic fluid inertia device according to claim 1, characterized in that: The number of the second pistons (6) is two and they are arranged on both sides of the first piston (4); the number of the second cavities (502) is two and they are respectively located on both sides of the first cavity (501).

5. A variable cross-section hydraulic fluid inertia device according to claim 4, characterized in that: The internal cavity of the variable cross-section hydraulic cylinder (5) is in a dumbbell shape with large ends and a small middle. The first cavity (501) and the two second cavities (502) are both cylindrical in shape. The diameter of the bottom surface of the cylinder of the second cavities (502) at the two ends is larger than the diameter of the bottom surface of the cylinder of the first cavity (501) in the middle.

6. A variable cross-section hydraulic fluid inertia device according to claim 4, characterized in that: It also includes a permanent magnet (8), the permanent magnet (8) includes a first permanent magnet group and a second permanent magnet group, the first permanent magnet group includes a first left permanent magnet and a first right permanent magnet, the first left permanent magnet is installed on the left side of the second cavity (502) on the left side, the first right permanent magnet is installed on the left side of the second piston (6) on the left side, the second permanent magnet group includes a second left permanent magnet and a second right permanent magnet, the second left permanent magnet is installed on the right side of the second piston (6) on the right side, the second right permanent magnet is installed on the right side of the second cavity (502) on the right side, the first left permanent magnet and the first right permanent magnet have magnetic poles that repel each other, and the second left permanent magnet and the second right permanent magnet have magnetic poles that repel each other, and when the piston rod (2) moves in a direction away from the bottom of the second cavity (502) of the variable cross-section hydraulic cylinder (5), the second piston (6) is reset under the action of the permanent magnet (8).

7. A variable cross-section hydraulic fluid inertia device according to claim 1, characterized in that: It also comprises a connecting member (1), wherein the connecting member (1) is connected to a structure requiring shock absorption.

8. The variable cross-section hydraulic fluid inertia device according to claim 1, characterized in that: It also includes a first oil port (3), a second oil port (9) and a spiral tube (7), wherein the first oil port (3) and the second oil port (9) are located on different sides of the first piston (4), and the first oil port (3) and the second oil port (9) are connected via a spiral tube (7) arranged outside the variable-section hydraulic cylinder (5).

9. A hydraulic system, characterized in that: The hydraulic system comprises a variable cross-section hydraulic fluid inertia device as described in any one of claims 1-8.

10. A method for adjusting the inertia coefficient of a variable cross-section hydraulic fluid inertia device according to any one of claims 1 to 8, characterized in that: The following steps are involved: Obtaining the inertia coefficient requirement of the application scenario, adjusting the movement stroke of the piston rod, and calculating the inertia coefficient of the variable-section hydraulic fluid inertia device until the inertia coefficient requirement is met; The calculation expression of the inertia coefficient of the variable cross-section hydraulic fluid inertia device is: In the formula, m in is the inertia coefficient, x is the movement stroke of the piston rod, x1 is the movement stroke of the piston rod when the first piston (4) contacts the second piston (6), x2 is the maximum unidirectional stroke of the piston rod (2), A1 is the working area of ​​the first piston (4), A2 is the working area of ​​the second piston (6), A3 is the cross-sectional area of ​​the spiral tube (7), r1 is the radius of the spiral tube (7), h is the pitch of the spiral tube (7), l is the length of the spiral tube (7), and ρ is the density of the liquid in the hydraulic cylinder.

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