Polyurethane foam pad shock absorber for railway vehicle and using method of polyurethane foam pad shock absorber

Abstract

The invention relates to the technical field of railway vehicle damping, in particular to a polyurethane foam pad damper for a railway vehicle and a using method thereof.The polyurethane foam pad damper for the railway vehicle comprises a plurality of bases which are arranged between vehicle floor interlayers and connected end to end, each base is of a hollow cuboid structure, and the surface of each base is subjected to anodic oxidation treatment; the multi-layer composite vibration reduction unit is composed of a polyurethane foam layer and a high-damping rubber layer nested in the polyurethane foam layer, the molecular structure of the polyurethane foam layer is in a porous cell form, and the internal porous cell form is in internal and external surrounding type gradient distribution, that is, the outer-layer aperture of the polyurethane foam layer is smaller than the inner-layer aperture of the polyurethane foam layer. The polyurethane foam layer and the high-damping rubber layer are compounded, the polyurethane foam layer adopts aperture gradient distribution, the outer-layer small-aperture foam quickly responds to high-frequency vibration, and the inner-layer large-aperture foam absorbs low-frequency energy and covers full-band vibration suppression, so that vibration transmission is attenuated, noise in a vehicle is reduced, and the comfort of passengers is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration damping for rail vehicles, and particularly to a polyurethane foam pad shock absorber for rail vehicles and its usage method. Background Technique

[0002] The vibration damping system is an indispensable part of rail vehicles, which can effectively improve the running smoothness and comfort of trains. Especially in high-speed trains, urban rail transit, and structures that require high sound insulation. It can effectively improve the sound insulation performance of double-layer structures. On rail vehicles, the floor is a sandwich structure. By changing parameters such as the stiffness, hardness, and damping of the connection between the double-layer floors, the sound insulation performance of the floor structure can be effectively improved, thereby suppressing vibrations and noises inside the vehicle.

[0003] The patent application No. CN202010053099.7 discloses a rail vehicle shock absorber, which includes a base assembly with an oil storage cylinder sealed and fixed at the inner end; an oil cylinder disposed inside the oil storage cylinder, and one end of the oil cylinder is sealed and fixedly connected to the inner end of the base assembly; an end cover assembly, which is sealed and fixedly connected to the other end of the oil cylinder and the oil storage cylinder; a piston assembly disposed inside the oil cylinder; a piston rod assembly passing through the end cover assembly; rubber joints are provided at the outer ends of the piston rod assembly and the base assembly; damping valves for externally adjusting the damping force magnitude are provided on both the base assembly and the end cover assembly. In the present invention, damping valves for externally adjusting the damping force magnitude are provided on both the base assembly and the end cover assembly, and the adjustment is very convenient without disassembling the entire shock absorber, thereby greatly improving the adjustment efficiency of the valve system damping force.

[0004] Traditionally, using rubber as a vibration damping component is prone to aging and has poor stiffness stability in high and low temperature environments, resulting in a decline in sound insulation performance and high maintenance costs; single-material shock absorbers are difficult to cover broadband vibrations and cannot adapt to dynamic load changes under complex working conditions of rail vehicles. Summary of the Invention

[0005] In order to overcome the defects in the prior art, the purpose of the present invention is to provide a polyurethane foam pad shock absorber for rail vehicles and its usage method, which improves the broadband vibration damping performance through material compounding and structural optimization, introduces an intelligent adjustment module to achieve dynamic stiffness adaptation, and is applicable to vibration suppression and noise control of the double-layer floor structure of rail vehicles, especially for the requirements of high-frequency vibration energy absorption and dynamic stiffness adjustment, so as to solve the problems raised in the above background technique.

[0006] To achieve the above purpose, the present invention provides a polyurethane foam pad shock absorber for rail vehicles, including a number of bases connected end to end and placed between the sandwich layers of the vehicle floor. The bases are in a hollow cuboid structure and their surfaces are anodized. A number of pressure-resistant plates are symmetrically provided inside the bases, and a number of pressure-resistant cavities are provided between the pressure-resistant plates and the inner walls of the bases; The multi-layer composite vibration reduction unit is composed of a polyurethane foam layer and a high damping rubber layer embedded therein, wherein the molecular structure of the polyurethane foam layer is in the form of porous cells, and the porous cell morphology inside the polyurethane foam layer is in the form of an inner-outer surrounding gradient distribution, that is, the outer pore size of the polyurethane foam layer is smaller than the inner pore size; The intelligent adjustment module is embedded in the bottom surface of the polyurethane foam layer and includes a pressure sensor and a stiffness adjustment component. The stiffness adjustment component changes the filling gas pressure in a plurality of pressure-resistant cavities by receiving pressure change information from the pressure sensor, thereby adjusting the base stiffness in real time.

[0007] As a further improvement of the technical solution, nano-silicon dioxide particles are added to the polyurethane foam layer, accounting for 1%-3% by mass, with an internal pore size of 0.1-10um, and the ratio of the dynamic elastic modulus to the static elastic modulus of the polyurethane foam layer is 1.5-2.0.

[0008] As a further improvement of the technical solution, the high damping rubber layer is a composite of nitrile rubber and graphene, with a thickness of 2-5 mm and a loss factor of ≥0.25.

[0009] As a further improvement of the technical solution, the stiffness adjustment component includes an air pump, a plurality of pipes leading into a plurality of bases, and a solenoid valve installed at the end of each pipe.

[0010] As a further improvement of the technical solution, a connecting sleeve is arranged between the ends of two adjacent bases, a plurality of sealing sleeves are arranged inside the connecting sleeve, and the two ends of the plurality of sealing sleeves are adapted to be matched with the plurality of pressure-resistant cavities at the ends of the two adjacent bases.

[0011] As a further improvement of the technical solution, the connecting sleeve and the plurality of sealing sleeves are made of high-damping rubber to form an integrally formed structure.

[0012] As a further improvement of the technical solution, limiting ribs are protruding from both side edges of the top surface of the base, and the polyurethane foam layer is snap-fitted with a pair of limiting ribs.

[0013] As a further improvement of the technical solution, the base and the plurality of pressure-resistant plates are made of 6061-T6 aluminum material to form an integrally formed structure.

[0014] As a further improvement of the technical solution, the multilayer composite vibration damping unit and the base contact surface are bonded with epoxy resin adhesive, the mixed density of the adhesive is 1.35±0.05g / cm³, and the tensile strength after curing is ≥4MPa.

[0015] The present invention provides a method for using a polyurethane foam pad shock absorber for a rail vehicle, comprising the following steps: S1. Arrange and fix a plurality of bases in a head-to-tail array between the double floors of a rail vehicle; S2, and butt the ends of two adjacent bases through a connecting sleeve; S3, then install a plurality of pipes on one side of a plurality of bases and connect them to an air pump; S4. When the vehicle floor is subjected to the excitation of the ground, the vibration energy is transmitted from the outer floor to the inner floor, and then the vibration energy transmitted to the inner floor is effectively reduced through the base and the multi-layer composite vibration reduction unit; S5, when the polyurethane foam layer is subjected to external force, the porous cell structure will deform, consuming a large amount of energy through air damping and mechanical damping, thereby absorbing and dispersing vibration energy; S6. The vibration frequency is collected in real time through the pressure sensor, and according to the preset algorithm, the pipeline on the corresponding side of the base is dynamically triggered to open and inflate to change the gas pressure in several pressure-resistant cavities, thereby adjusting the base stiffness in real time to promote the attenuation of vibration transmission.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The polyurethane foam pad shock absorber for rail vehicles and the use method thereof are compounded by setting a polyurethane foam layer and a high damping rubber layer, and the polyurethane foam layer adopts a pore size gradient distribution. The outer layer of small-pore foam quickly responds to high-frequency vibrations, and the inner layer of large-pore foam absorbs low-frequency energy, covering the entire frequency band of vibration suppression, thereby attenuating vibration transmission, reducing noise inside the vehicle, and significantly improving passenger comfort.

[0017] 2. The polyurethane foam pad shock absorber for rail vehicles and its use method, through the intelligent adjustment module, adjusts the gas pressure in the pressure-resistant cavity through the air pump and the solenoid valve. The overall stiffness of the shock absorber can be continuously adjusted within the range of 500-1000N / mm, which is suitable for different working conditions of rail vehicle starting, braking and cornering. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the drawings are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art, under the guidance of the present invention, select various possible shapes and proportional dimensions to implement the present invention according to specific circumstances.

[0019] Figure 1 It is a schematic diagram of the partial assembly structure of the present invention; Figure 2 It is a disassembled diagram of the base assembly of the present invention; Figure 3 It is a schematic diagram of the overall sound insulation effect of the present invention; Figure 4 It is a schematic diagram of the overall vibration reduction attenuation trend of the present invention; Figure 5 This is the overall vibration transmission path diagram of the present invention; The meanings of the various labels in the figure are as follows: 100, base; 110, compression plate; 120, connecting sleeve; 121, sealing sleeve; 130, limiting rib; 200, multi-layer composite vibration damping unit; 300, pressure sensor; Specific embodiments

[0020] Combined with the description of the specific embodiments of the present invention and the accompanying drawings, the details of the present invention can be more clearly understood. However, the specific embodiments of the present invention described herein are only for the purpose of explaining the present invention and cannot be understood in any way as a limitation of the present invention. Under the teaching of the present invention, the concepts of those skilled in the art are based on any possible deformations of the present invention, and all of these should be regarded as belonging to the scope of the present invention. The terms "installation" and "connection" should be understood in a broad sense, which can be directly connected or indirectly connected through an intermediate medium.

[0021] The orientation or positional relationship indicated by the terms "central axis", "vertical", "horizontal", "front", "rear", "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", etc. used herein is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, in the description of the present invention, the meaning of "several" is two or more, unless otherwise specifically defined.

[0022] Please refer to Figures 1 - 5 As shown, the present invention provides a polyurethane foam pad shock absorber for rail vehicles, including a number of base 100 connected end to end and placed between the vehicle floor interlayers. It has a hollow cuboid structure and its surface is anodized to improve corrosion resistance; a number of compression plates 110 are symmetrically arranged inside the base 100, and the base 100 and a number of compression plates 110 are made of 6061-T6 aluminum alloy to form an integrally formed structure; a number of compression cavities are provided between a number of compression plates 110 and the inner wall of the base 100 to reduce weight and ensure stiffness; The multi-layer composite vibration damping unit 200 is composed of a polyurethane foam layer and a high damping rubber layer nested inside it. The molecular structure of the polyurethane foam layer is in a pore-like cell form, and the pore-like cell form inside it is in an inner and outer surrounded gradient distribution, that is, the outer pore diameter of the polyurethane foam layer is smaller than the inner pore diameter; the outer pore diameter is 0.1 - 1 μm, and the inner pore diameter is 5 - 10 μm, enhancing the broadband vibration absorption ability; the polyurethane foam layer is prepared by gradient foaming technology, and the foaming temperature is controlled to decrease from the center to the edge to form a pore diameter gradient distribution; The intelligent adjustment module is embedded in the bottom surface of the polyurethane foam layer 21 and includes a pressure sensor 300 and a stiffness adjustment component. The stiffness adjustment component changes the filling gas pressure in a number of compressive cavities by receiving the pressure change information of the pressure sensor 300, thereby adjusting the stiffness of the base 100 in real time.

[0023] Furthermore, nano-silica particles are added to the polyurethane foam layer, with a mass ratio of 1%-3%, to improve the dynamic elastic modulus and creep resistance; its internal pore diameter is 0.1-10um, and the ratio of the dynamic elastic modulus to the static elastic modulus of the polyurethane foam layer is 1.5-2.0; the dynamic modulus is significantly higher than the static modulus, indicating that the material has a higher stiffness response under vibration loads such as high-frequency impact or cyclic stress. This characteristic enables the polyurethane foam to quickly adapt to changes in vibration frequency and effectively absorb vibration energy in the frequency band of 50-200Hz, reducing the transmission of vibration to the interior of the vehicle; in addition, the higher dynamic modulus ratio indicates that the material significantly improves the energy dissipation efficiency through the compression-rebound cycle of the cell structure, combined with air damping and internal friction of the material, during the dynamic deformation process, thereby reducing the vibration transmission rate; that is, through the differential response of the material mechanical properties, the core technical effects of broadband vibration reduction, durability improvement, and dynamic and static load adaptation are achieved.

[0024] Furthermore, the high-damping rubber layer is a composite of nitrile rubber and graphene, with a thickness of 2-5mm, and its loss factor ≥0.25, adapting to extreme temperatures of -40°C to 80°C.

[0025] Specifically, the stiffness adjustment component includes an air pump, a number of pipes leading into a number of bases 100, and solenoid valves installed at the ends of each pipe. The pipes penetrate into a number of compressive cavities, and by adjusting the gas pressure in the number of compressive cavities, the stiffness of the base 100 can be continuously adjusted within the range of 500-1000N / mm to adapt to different operating conditions of the rail vehicle.

[0026] Furthermore, a connecting sleeve 120 is provided between the ends of two adjacent bases 100. A number of sealing sleeves 121 are provided inside the connecting sleeve 120, and the two ends of the number of sealing sleeves 121 are correspondingly and adaptively sleeved with a number of compressive cavities at the ends of two adjacent bases 100, so that the bases 100 are connected to each other; the connecting sleeve 120 and the number of sealing sleeves 121 are integrally formed of high-damping rubber.

[0027] Furthermore, limiting ribs 130 are convexly provided on both sides of the top surface of the base 100, and the polyurethane foam layer is clamped and matched with the pair of limiting ribs 130, so that the polyurethane foam layer can be positioned and aligned during bonding.

[0028] Furthermore, the contact surface between the multi-layer composite vibration damping unit 200 and the base 100 is bonded with an epoxy resin adhesive. After the pretreatment of the base 100 according to the process of "cleaning - grinding - cleaning", the bonding is carried out. The ratio of the main agent to the curing agent of the adhesive is 2:1, the amount of glue applied is 0.35 - 0.5 kg / m², heat curing treatment is adopted, the mixed density of the adhesive is 1.35 ± 0.05 g / cm³, and the tensile strength after curing is ≥ 4 MPa.

[0029] The usage method of the polyurethane foam pad shock absorber for rail vehicles of the present invention includes the following steps: S1. A number of bases 100 are arranged and fixed in a head-to-tail array between the double floors of the rail vehicle; the contact surface between the base 100 and the vehicle floor is bonded with a two-component acrylic glue; S2. The ends of adjacent two bases 100 are docked through a connecting sleeve 120; S3. Then a number of pipes are installed on one side of a number of bases 100 and connected to an air pump; S4. When the vehicle floor is excited by the ground, the vibration energy is transmitted from the outer floor to the inner floor, and then the vibration energy transmitted to the inner floor is effectively reduced through the base 100 and the multi-layer composite vibration damping unit 200; S5. When the polyurethane foam layer is subjected to an external force, the pore-like cell structure will deform, and a large amount of energy is consumed through two ways of air damping and mechanical damping, thereby absorbing and dispersing the vibration energy; S6. The vibration frequency is collected in real time through a pressure sensor 300, and the gas pressure in a number of compression cavities is changed by dynamically triggering the pipes on one side of the corresponding base 100 to be opened and inflated according to a preset algorithm, and then the stiffness of the base 100 is adjusted in real time to make the vibration transmission attenuation rate ≥ 25 dB. Embodiment

[0030] When the structure is subjected to forced vibration, Ze represents the impedance of the outer floor, Zi represents the impedance of the elastic support, Za represents the impedance of the inner floor, Ve represents the vibration velocity of the outer floor, and Va represents the vibration velocity of the inner floor.

[0031] The vibration transmission attenuation rate is expressed as: | = 20lg| | When the impedance Zi of the elastic support is much smaller than the impedance of the inner floor, the vibration transmission can be effectively attenuated. Therefore, good vibration damping effect can be obtained through the design of the polyurethane foam pad shock absorber.

[0032] The length of the base 100 is 160 mm, the width is 50 mm, and the height is 51 mm; The upper and lower surfaces of the base 100 have a thickness of 2.5 mm, the compressive plate 110 has a thickness of 1.5 mm, and the height of the base 100 is 41 mm; The polyurethane foam layer is of type SR110, with a length of 160 mm, a width of 46 mm, and a height of 12.5 mm; the mechanical loss factor is 0.14, the applicable temperature range is -30°C to 70°C, the static elastic modulus is 0.83 N / mm², and the dynamic elastic modulus is 1.52 N / mm². The sound insulation effect of the polyurethane foam is as Figure 3 shown.

[0033] It should be noted that the above embodiments are only for explaining the technical concept and features of the present invention, and the purpose is to enable those familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. Polyurethane foam pad shock absorber for rail vehicles, characterized in that: The invention comprises a plurality of bases (100) connected end to end and placed between the vehicle floor interlayers, the bases (100) are in a hollow rectangular structure and the surface of the bases (100) is anodized, a plurality of pressure-resistant plates (110) are symmetrically arranged inside the bases (100), and a plurality of pressure-resistant cavities are arranged between the plurality of pressure-resistant plates (110) and the inner wall of the bases (100); The multi-layer composite vibration damping unit (200) is composed of a polyurethane foam layer and a high damping rubber layer embedded therein, wherein the molecular structure of the polyurethane foam layer is in a porous cell form, and the porous cell form inside the polyurethane foam layer is in an inner-outer surrounding gradient distribution, that is, the outer layer pore size of the polyurethane foam layer is smaller than the inner layer pore size; An intelligent adjustment module is embedded in the bottom surface of the polyurethane foam layer (21), and comprises a pressure sensor (300) and a stiffness adjustment component. The stiffness adjustment component changes the filling gas pressure in a plurality of pressure-resistant cavities by receiving pressure change information from the pressure sensor (300), thereby adjusting the stiffness of the base (100) in real time.

2. The polyurethane foam pad shock absorber for rail vehicles according to claim 1, characterized in that: Nano silicon dioxide particles are added to the polyurethane foam layer, accounting for 1% to 3% by mass, and the internal pore diameter is 0.1 to 10 um. The ratio of the dynamic elastic modulus to the static elastic modulus of the polyurethane foam layer is 1.5 to 2.

0.

3. The polyurethane foam pad shock absorber for rail vehicles according to claim 2, characterized in that: The high damping rubber layer is a composite of nitrile rubber and graphene, with a thickness of 2-5 mm. Its loss factor is ≥0.

25.

4. The polyurethane foam pad shock absorber for rail vehicles according to claim 3, characterized in that: The stiffness adjustment component comprises an air pump, a plurality of pipes passing into a plurality of bases (100), and a solenoid valve installed at the end of each pipe.

5. The polyurethane foam pad shock absorber for rail vehicles according to claim 4, characterized in that: A connecting sleeve (120) is provided between the ends of two adjacent bases (100), a plurality of sealing sleeves (121) are provided inside the connecting sleeve (120), and the two ends of the plurality of sealing sleeves (121) are adapted to be correspondingly connected to the plurality of pressure-resistant cavities at the ends of the two adjacent bases (100).

6. The polyurethane foam pad shock absorber for rail vehicles according to claim 5, characterized in that: The connecting sleeve (120) and the plurality of sealing sleeves (121) are made of high-damping rubber to form an integrally formed structure.

7. The polyurethane foam pad shock absorber for rail vehicles according to claim 6, characterized in that: Limiting ribs (130) are protruding from both sides of the top surface of the base (100), and the polyurethane foam layer is snap-fitted with a pair of limiting ribs (130).

8. The polyurethane foam pad shock absorber for rail vehicles according to claim 7, characterized in that: The base (100) and the plurality of pressure-resistant plates (110) are made of 6061-T6 aluminum material to form an integrally formed structure.

9. The polyurethane foam pad shock absorber for rail vehicles according to claim 8, characterized in that: The contact surfaces of the multilayer composite vibration damping unit (200) and the base (100) are bonded with epoxy resin adhesive, and the mixed density of the adhesive is 1.35±0.05 g / cm 3 , the tensile strength after curing is ≥4MPa.

10. A method for using a polyurethane foam pad shock absorber for a rail vehicle, the polyurethane foam pad shock absorber for a rail vehicle according to claim 9, characterized in that: The following steps are involved: S1. Arrange and fix a plurality of bases (100) in a head-to-tail array between the double floors of a rail vehicle; S2, and connecting the ends of two adjacent bases (100) via a connecting sleeve (120); S3, installing a plurality of pipes on one side of a plurality of bases (100) and connecting them to an air pump; S4. When the vehicle floor is subjected to vibration from the ground, the vibration energy is transmitted from the outer floor to the inner floor, and then the vibration energy transmitted to the inner floor is effectively reduced through the base (100) and the multi-layer composite vibration reduction unit (200); S5, when the polyurethane foam layer is subjected to external force, the porous cell structure will deform, consuming a large amount of energy through air damping and mechanical damping, thereby absorbing and dispersing vibration energy; S6. The vibration frequency is collected in real time through the pressure sensor (300), and according to a preset algorithm, the pipeline on one side of the corresponding base (100) is dynamically triggered to open and inflate, thereby changing the gas pressure in the plurality of pressure-resistant cavities, thereby adjusting the stiffness of the base (100) in real time, thereby promoting vibration transmission attenuation.

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