Multidirectional dynamic vibration absorption device for underground coal mine and design method

Abstract

The invention relates to a multidirectional dynamic vibration absorption device for an underground coal mine and a design method, the device comprises a box body and a vibration absorption main body, the box body is fixedly connected with a vibration main system, and the vibration absorption main body is installed in the box body; and fluid with damping is injected into the box body. The multidirectional dynamic vibration absorption device composed of the simple geometric curved surfaces and the rolling bodies is designed, an external power source is not needed, and vibration energy is consumed through rolling of the rolling bodies and sliding and collision of the vibration absorption bodies, so that the purpose of absorbing and weakening vibration of a main system is achieved; modal analysis is combined with a design method of the dynamic vibration absorber, the mounting position and related design parameters of the vibration absorber are determined according to different modes of a system, and a more effective vibration control method can be provided for the multi-degree-of-freedom system.

Description

Technical Field

[0001] The present application relates to the field of vibration absorption devices, and particularly to a multi-directional dynamic vibration absorption device and a design method for underground coal mines. Background Art

[0002] In order to reduce the vibration response of machinery and structures, especially when it is difficult to avoid resonance under various conditions, the existing method is to install various dynamic vibration absorbers. After adding a vibration absorber to the vibration main system, by appropriately selecting the dynamic parameters of the vibration absorber, the purpose of reducing its forced vibration response can be achieved near the resonance frequency point of the main vibration system. Since the passive dynamic vibration absorber has a simple structure, high stability and reliability, does not require an external power source, and can effectively suppress the vibration of machinery or structures with relatively small frequency changes, it has been applied in many fields. At the same time, the research and development of various passive dynamic vibration absorbers have also been continuously concerned by people.

[0003] Traditional passive dynamic vibration absorbers can only suppress the vibration of machinery or structures with relatively small frequency changes, while active control vibration absorbers have complex structures, high costs, and require additional energy sources. For underground equipment, explosion-proof requirements need to be met, which has limitations. With the current development trend of large capacity and high power of underground equipment such as tunnel drilling rigs and mud pump trucks, the severe vibration of the vehicle body has also increased, causing irreversible impacts on the service life and stability of equipment and accessories. Summary of the Invention

[0004] In order to overcome at least one deficiency in the prior art, the present application provides a multi-directional dynamic vibration absorption device and a design method for underground coal mines.

[0005] In a first aspect, a multi-directional dynamic vibration absorption device for underground coal mines is provided, including: a box body and a vibration absorption main body. The box body is fixedly connected to the vibration main system, and the vibration absorption main body is installed inside the box body; a fluid with damping is injected into the box body;

[0006] The vibration absorption main body includes at least one curved surface shell member. The curved surface shell member includes a first curved surface shell and a second curved surface shell. The first curved surface shell and the second curved surface shell are connected by buckling, and a sealed space is formed inside; rolling bodies are placed in the sealed space, and the rolling bodies can roll in the sealed space when subjected to external excitation;

[0007] At least one first vibration absorption member is installed at one end of the curved surface shell member. The first vibration absorption member includes a first guide rod arranged at one end of the curved surface shell member and a first sleeve installed at the top of the box body; the first guide rod extends into the first sleeve, and a first spring is arranged between the first guide rod and the first sleeve; there is a gap between the first sleeve and the curved surface shell member;

[0008] At the other end of the curved surface housing member, at least one second vibration absorber is installed. The second vibration absorber includes a second sleeve provided at the other end of the curved surface housing member and a second guide rod installed at the bottom end of the box body; the second guide rod extends into the second sleeve, and a second spring is provided between the second guide rod and the second sleeve; there is a gap between the second sleeve and the bottom end of the box body.

[0009] In one embodiment, both the first curved surface housing and the second curved surface housing are processed with arc curved surfaces having roughness, and the arc curved surfaces form the space walls of the sealed space.

[0010] In one embodiment, grooves are provided on both end faces of the first curved surface housing and the second curved surface housing that are opposite to each other, and sealing members are installed in the grooves.

[0011] In one embodiment, the box body is provided with a box body cover plate. The box body cover plate is provided with a box cover seat and a handle. A groove is provided on the box cover seat for installing a sealing member.

[0012] In one embodiment, mounting ear seats are provided at both the top end and the bottom end of the box body for fixedly connecting with the main vibration system or connecting other vibration absorption devices.

[0013] Second, a design method for a multi-directional dynamic vibration absorber used in underground coal mines is provided, including:

[0014] Step 1: Perform modal analysis on the main vibration system to determine at least one mode.

[0015] Step 2: Determine at least one mode that has a greater impact on the performance of the main vibration system among all modes as the key mode, and determine the corresponding position of each key mode as the installation position of the multi-directional dynamic vibration absorber.

[0016] Step 3: Determine the equivalent mass corresponding to each key mode in the main vibration system; if there is 1 key mode, the equivalent mass is the mass of the main vibration system; if there are more than 1 key modes, the equivalent mass corresponding to each key mode is:

[0017] M ei =[φi] T [m][φi]

[0018] where M ei is the equivalent mass corresponding to the i-th key mode, [φi] is the modal matrix corresponding to the i-th key mode, [m] is the mass matrix composed of multiple parts of the main system, and [φi] T is the transpose of [φi];

[0019] Step 4: The main vibration system and the multi-directional dynamic vibration absorber can be regarded as a three-degree-of-freedom model; the three-degree-of-freedom model includes the main vibration system, the box body and the fluid part, the curved surface housing and the rolling body part;

[0020] For any key mode, the equivalent mass corresponding to the key mode in the vibration main system is m1, the mass of the box body and the fluid part is m2, and the mass of the curved surface shell and the rolling element part is m3;

[0021] When the mass ratio μ of the multi-directional dynamic vibration absorber and the vibration main system is known, the parameters of the multi-directional dynamic vibration absorber are determined by the following formulas:

[0022] μ2 = 1.08μ 1.73

[0023] μ1 = μ - μ2

[0024] α = 1.34(μ + 0.33) 0.26

[0025] β = 0.57(μ + 0.457) -0.75

[0026] ζ3 = 0.81μ 0.34

[0027] Wherein, μ1 is the ratio of m2 to m1, μ2 is the ratio of m3 to m1, α is the ratio of the natural frequency of the box body and the fluid part to the natural frequency of the vibration main system, β is the ratio of the natural frequency of the curved surface shell and the rolling element part to the natural frequency of the vibration main system, and ζ3 is the damping ratio of the curved surface shell and the rolling element part.

[0028] Compared with the prior art, the present application has the following beneficial effects: The present application designs a multi-directional dynamic vibration absorber composed of a simple geometric body curved surface and rolling elements, which does not require an external power source, and consumes vibration energy through the rolling of the rolling elements and the sliding and collision of the vibration absorber body, so as to achieve the purpose of absorbing and weakening the vibration of the main system; Combining modal analysis with the design method of the dynamic vibration absorber, determining the installation position and related design parameters of the vibration absorber for different modes of the system, and providing a more effective vibration control method for a multi-degree-of-freedom system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present application can be better understood by referring to the description given below in conjunction with the accompanying drawings. The drawings, together with the following detailed description, are included in this specification and form a part of this specification. In the drawings:

[0030] Figure 1 The structural schematic diagram of the multi-directional dynamic vibration absorber for underground coal mines is shown;

[0031] Figure 2 The structural schematic diagram of the multi-directional dynamic vibration absorber for underground coal mines in another embodiment is shown;

[0032] Figure 3 Shows the longitudinal vibration absorption effect diagram of the multi-directional dynamic vibration absorber of the present application;

[0033] Figure 4 Shows the transverse vibration absorption dynamic model;

[0034] Figure 5 Shows the transverse vibration absorption effect diagram of the multi-directional dynamic vibration absorber of the present application;

[0035] Figure 6 Shows the structural schematic diagram of the multi-directional dynamic vibration absorber for underground coal mines in another embodiment;

[0036] Figure 7 Shows the schematic diagram of the three-degree-of-freedom model.

[0037] Reference numerals:

[0038] 101 - Box cover plate, 102 - Handle, 103 - Box cover seat, 104 - Fluid;

[0039] 201 - First curved surface housing, 202 - Second curved surface housing, 203 - First guide rod, 204 - Second sleeve, 205 - Second guide rod, 206 - First sleeve, 207 - First spring, 208

[0040] - Second spring, 209 - Sealed space, 210 - Rolling body. Detailed implementation manners

[0041] In the following, exemplary embodiments of the present application will be described with reference to the accompanying drawings. For clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many embodiment-specific decisions may be made during the development of any such actual embodiment to achieve the specific goals of the developer, and these decisions may vary with different embodiments.

[0042] Here, it should also be noted that, in order to avoid obscuring the present application with unnecessary details, only the device structures closely related to the solution of the present application are shown in the drawings, while other details less related to the present application are omitted.

[0043] It should be understood that the present application is not limited to the described embodiments only due to the following description with reference to the drawings. In this document, where feasible, embodiments can be combined with each other, features can be replaced or borrowed between different embodiments, and one or more features can be omitted in one embodiment.

[0044] The embodiments of the present application provide a multi-directional dynamic vibration absorber for underground coal mines, Figure 1 Shows the structural schematic diagram of the multi-directional dynamic vibration absorber for underground coal mines, seeFigure 1 , the device includes: a box body and a vibration absorption main body. The box body is fixedly connected to the vibration main system, and the vibration absorption main body is installed inside the box body; a fluid 104 with damping is injected into the box body; here, the fluid can be water or hydraulic oil, etc., and the fluid 104 can fill the box body or the remaining liquid level height.

[0045] The vibration absorption main body includes at least one curved surface shell part. The curved surface shell part includes a first curved surface shell 201 and a second curved surface shell 202. The first curved surface shell 201 and the second curved surface shell 202 are connected by buckling, and a sealed space 209 is formed inside; rolling elements 201 are placed in the sealed space 209, and the rolling elements 201 can roll in the sealed space 209 when subjected to external excitation; here, the rolling elements 201 can be spherical bodies, ellipsoidal bodies, or cylindrical bodies, and the number can be 1 or more. Both the first curved surface shell 201 and the second curved surface shell 202 are processed with arc curved surfaces having roughness, and the arc curved surfaces form the space walls of the sealed space 209.

[0046] Specifically, grooves are provided on both end faces of the first curved surface shell 201 and the second curved surface shell 202 that are oppositely arranged, and seals are installed in the grooves. The seals can be O-ring seals or seals of other materials and shapes.

[0047] At least one first vibration absorption member is installed at one end of the curved surface shell part. The first vibration absorption member includes a first guide rod 203 provided at one end of the curved surface shell part and a first sleeve 206 installed at the top of the box body; the first guide rod 203 extends into the first sleeve 206, and a first spring 207 is provided between the first guide rod 203 and the first sleeve 206; there is a gap between the first sleeve 206 and the curved surface shell part;

[0048] At least one second vibration absorption member is installed at the other end of the curved surface shell part. The second vibration absorption member includes a second sleeve 204 provided at the other end of the curved surface shell part and a second guide rod 205 installed at the bottom end of the box body; the second guide rod 205 extends into the second sleeve 204, and a second spring 208 is provided between the second guide rod 205 and the second sleeve 204; there is a gap between the second sleeve 204 and the bottom end of the box body. Here, the spring can be a linear spring or a non-linear spring according to the actual working conditions.

[0049] In the above embodiment, as Figure 1 shown, one first vibration absorption member and one second vibration absorption member can be provided respectively, Figure 2 shows a structural schematic diagram of a multi-directional dynamic vibration absorption device for underground coal mines in another embodiment. As Figure 2 shown, two first vibration absorption members and two second vibration absorption members can also be provided respectively, or more.

[0050] When the main vibration system receives external vibration excitation, vibrations in different directions are generated. The vibration absorption body moves up and down along the guide rod. When the vibration intensity is high, the second curved surface housing may collide with the lower surface of the box body, and the first curved surface housing may collide with the sleeve on the box cover. The longitudinal vibration of the vibration system is dissipated through the vibration absorption body compressing the spring along the guide rod and through collisions. The sphere rolls in any direction on the arc surface of the curved surface housing and may also collide with the arc surface, which can reduce and absorb the lateral vibration and axial movement of the vibration system.

[0051] Figure 3 The longitudinal vibration absorption effect diagram of the multi-directional dynamic vibration absorber of the present application is shown. In the figure, the vertical axis X1 is the system amplitude magnification factor, and the horizontal axis λ is the ratio of the excitation frequency to the system natural frequency. It can be seen that the vibration absorber involved in the present application has a better vibration absorption effect in longitudinal vibration.

[0052] Figure 4 The lateral vibration absorption dynamic model is shown. Figure 5 The lateral vibration absorption effect diagram of the multi-directional dynamic vibration absorber of the present application is shown. The lateral vibration is mainly absorbed by the movement of the rolling elements in the curved surface. The system can be simplified into a model as shown in Figure 4 By using the fixed-point theory to obtain the optimal design parameters of the vibration absorber and comparing the amplitude magnification factors of the case with and without the vibration absorber installed, it can be seen that the present application can effectively reduce the amplitude of the lateral vibration and effectively avoid the vibration amplitude at the resonance frequency.

[0053] Figure 6 The structural schematic diagram of the multi-directional dynamic vibration absorber for underground coal mines in another embodiment is shown. Two curved surface housing parts can be provided, and the two curved surface housing parts are connected in sequence. The multi-directional dynamic vibration absorber is horizontally installed in the box body, and the rolling element is cylindrical. This installation method can be applied to structures mainly with lateral vibration.

[0054] In other embodiments, the multi-directional dynamic vibration absorbers in each of the foregoing embodiments can be longitudinally stacked and installed to form a two-stage or multi-stage series dynamic vibration absorber.

[0055] In other embodiments, the multi-directional dynamic vibration absorbers in each of the foregoing embodiments can be installed side by side and combined to form a double or multiple parallel dynamic vibration absorber.

[0056] Further, the box body is provided with a box body cover plate 101. A box cover seat 103 and a handle 102 are provided on the box body cover plate 101. A groove is provided on the box cover seat 103 for installing a seal. The box cover seat 103 and the box cover plate 101 are connected by bolts.

[0057] Further, mounting lugs are provided at both the top end and the bottom end of the box body for fixedly connecting with the main vibration system or connecting other vibration absorption devices.

[0058] In summary, the multi-directional dynamic vibration absorber of the present application has the following technical effects:

[0059] 1. Traditional passive dynamic vibration absorbers can only suppress the vibration of machinery or structures with relatively small frequency changes. The vibration absorber of the present application can adapt to different frequency bandwidths and can absorb and consume vibrations in multiple directions.

[0060] 2. Active control vibration absorbers have complex structures, high costs, and require additional energy sources, which have limitations for downhole equipment that needs to meet explosion-proof requirements. The vibration absorber of the present application is composed of simple geometric body surfaces and rolling elements, does not require an external power source, has a simple structure, and has diverse and flexible combination and arrangement methods, and can be widely applied in engineering practice.

[0061] The embodiment of the present application also provides a design method for a multi-directional dynamic vibration absorber for coal mine underground, including:

[0062] Step 1, perform modal analysis on the vibration main system to determine at least one mode; here, the modal analysis method of finite elements can be used to obtain each mode and the corresponding natural frequency of the vibration main system under external vibration excitation.

[0063] Step 2, determine at least one mode that has a greater impact on the performance of the vibration main system among all modes as the key mode, and determine the corresponding position of each key mode as the installation position of the multi-directional dynamic vibration absorber.

[0064] During the process of modal analysis, the mode corresponding to the position with higher energy or significant deformation can be determined according to the waveform as the key mode, and this position is the position corresponding to the key mode. The key mode can be, for example, the second-order mode or the third-order mode.

[0065] Step 3, determine the equivalent mass corresponding to each key mode in the vibration main system; if there is 1 key mode, the equivalent mass is the mass of the vibration main system; if the number of key modes is greater than 1, the equivalent mass corresponding to each key mode is:

[0066] M ei =[φi] T [m][φi]

[0067] where M ei is the equivalent mass corresponding to the i-th key mode, [φi] is the modal matrix corresponding to the i-th key mode, [m] is the mass matrix composed of multiple parts of the main system, and [φi] 1 is the transpose of [φi];

[0068] Step 4: The vibration main system and the multi-directional dynamic vibration absorber can be regarded as a three-degree-of-freedom model; the three-degree-of-freedom model includes the vibration main system, the box and fluid part, the curved surface shell and the rolling body part; Figure 7 The schematic diagram of the three-degree-of-freedom model is shown.

[0069] For any key mode, the equivalent mass corresponding to the key mode in the vibration main system is m1, the spring stiffness is k1, the damping is c1, the mass of the box and fluid part is m2, the spring stiffness is k2, the damping is c2, the mass of the curved surface shell and the rolling body part is m3, the spring stiffness is k3, and the damping is c3. c1 = c2 = 0.

[0070] Establish the motion equation and solve to obtain the amplitude magnification ratio X1 of the main system:

[0071]

[0072] Among them, A, B, C, and D are intermediate parameters.

[0073] μ1 is the ratio of m2 to m1, μ2 is the ratio of m3 to m1, α is the ratio of the natural frequency ω2 of the box and fluid part to the natural frequency ω1 of the vibration main system, β is the ratio of the natural frequency ω3 of the curved surface shell and the rolling body part to the natural frequency ω1 of the vibration main system: ζ3 is the damping ratio of the curved surface shell and the rolling body part; λ is the ratio of the excitation frequency ω to the natural frequency ω1 of the main system.

[0074] Given μ1, optimize the remaining parameters μ2, α, β, and ζ3 to minimize the peak value of the amplitude magnification ratio of the main system. The optimization expression is:

[0075]

[0076] Among them, F, that is, X1, is a function of the parameters μ2, α, β, and ζ3.

[0077] According to the above optimization expression, a large number of optimal parameter examples of the vibration absorber are obtained, and the optimal design parameters of the vibration absorber are obtained through the fitting equation.

[0078] Finally, given the mass ratio μ of the multi-directional dynamic vibration absorber to the vibration main system, μ = μ1 + μ2, determine the parameters of the multi-directional dynamic vibration absorber, using the following formula:

[0079] μ2 = 1.08μ 1.73

[0080] μ1 = μ - μ2

[0081] α = 1.34(μ + 0.33) 0.26

[0082] β = 0.57(μ + 0.457) -0.75

[0083] ζ3 = 0.81μ 0.34

[0084] Wherein, μ1 is the ratio of m2 to m1, μ2 is the ratio of m3 to m1, α is the ratio of the natural frequency of the box body and the fluid part to the natural frequency of the main vibration system, β is the ratio of the natural frequency of the curved surface shell and the rolling element part to the natural frequency of the main vibration system, and ζ3 is the damping ratio of the curved surface shell and the rolling element part.

[0085] As described above, these are only various embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A multi-directional dynamic vibration absorber for underground coal mines, characterized in that, Comprising: A box body and a vibration damping main body, the box body is fixedly connected to the vibration main system, and the vibration damping main body is installed inside the box body; a fluid (104) with damping is injected into the box body; The vibration damping main body includes at least one curved surface shell member, the curved surface shell member includes a first curved surface shell (201) and a second curved surface shell (202), the first curved surface shell (201) and the second curved surface shell (202) are buckled and connected, and a sealed space (209) is formed inside; rolling elements (210) are placed in the sealed space (209), and the rolling elements (210) can roll in the sealed space (209) when subjected to external excitation; At least one first vibration damping member is installed at one end of the curved surface shell member, the first vibration damping member includes a first guide rod (203) provided at one end of the curved surface shell member and a first sleeve (206) installed at the top end of the box body; the first guide rod (203) extends into the first sleeve (206), and a first spring (207) is provided between the first guide rod (203) and the first sleeve (206); there is a gap between the first sleeve (206) and the curved surface shell member; At least one second vibration damping member is installed at the other end of the curved surface shell member, the second vibration damping member includes a second sleeve (204) provided at the other end of the curved surface shell member and a second guide rod (205) installed at the bottom end of the box body; the second guide rod (205) extends into the second sleeve (204), and a second spring (208) is provided between the second guide rod (205) and the second sleeve (204); there is a gap between the second sleeve (204) and the bottom end of the box body.

2. The device according to claim 1, characterized in that, Both the first curved surface shell and the second curved surface shell are processed with arc curved surfaces having roughness, and the arc curved surfaces form the space walls of the sealed space (209).

3. The device according to claim 1, characterized in that, Grooves are provided on both end faces of the first curved surface shell and the second curved surface shell that are oppositely arranged, and sealing members are installed in the grooves.

4. The device according to claim 1, characterized in that, The box body is provided with a box body cover plate (101), the box body cover plate (101) is provided with a box cover seat (103) and a handle (102), and a groove is provided on the box cover seat (103) for installing a sealing member.

5. The device according to claim 1, characterized in that, Mounting ear seats are provided at both the top end and the bottom end of the box body for fixedly connecting to the vibration main system or connecting other vibration damping devices.

6. A design method for a multi-directional dynamic vibration absorber used in underground coal mines, characterized in that, Comprising: Step 1, perform modal analysis on the vibration main system to determine at least one mode; Step 2, determine at least one mode that has a greater impact on the performance of the vibration main system among all modes as the key mode, and determine the position corresponding to each key mode as the installation position of the multi-directional dynamic vibration absorber; Step 3, determine the equivalent mass corresponding to each key mode in the vibration main system; if the key mode is 1, the equivalent mass is the mass of the vibration main system; if the key mode is greater than 1, the equivalent mass corresponding to each key mode is: M ei = [φi] T [m][φi] Among them, M ei is the equivalent mass corresponding to the i-th key mode, [φi] is the mode matrix corresponding to the i-th key mode, [m] is the mass matrix composed of multiple parts divided by the main system, and [φi] T is the transpose of [φi]; Step 4, the vibration main system and the multi-directional dynamic vibration absorber can be regarded as a three-degree-of-freedom model; the three-degree-of-freedom model includes a vibration main system, a box body and a fluid part, a curved surface shell and a rolling body part; For any critical mode, the equivalent mass corresponding to the critical mode in the vibration main system is m1, the mass of the box body and the fluid part is m2, and the mass of the curved surface shell and the rolling body part is m3; When the mass ratio μ of the multi-directional dynamic vibration absorber to the vibration main system is known, determine the parameters of the multi-directional dynamic vibration absorber by using the following formula: μ2 = 1.08μ 1.73 μ1 = μ - μ2 α = 1.34(μ + 0.33) 0.26 β = 0.57(μ + 0.457) -0.75 ζ3 = 0.81μ 0.34 where μ1 is the ratio of m2 to m1, μ2 is the ratio of m3 to m1, α is the ratio of the natural frequency of the box body and the fluid part to the natural frequency of the vibration main system, β is the ratio of the natural frequency of the curved surface shell and the rolling body part to the natural frequency of the vibration main system: ζ3 is the damping ratio of the curved surface shell and the rolling body part.

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