A pneumatic vibration isolator

Abstract

A pneumatic vibration isolator includes a shell, a base plate, and a piston. The chamber enclosed by the shell and the piston is a main air chamber, and the chamber formed by the shell and the base plate is a secondary air chamber. A through hole is provided between the main air chamber and the secondary air chamber, and an adaptively adjustable damping component is provided in the through hole. A throttle hole is provided on the adaptively adjustable damping component. The present invention directly adjusts the inner diameter of the throttle hole through the adaptively adjustable damping component without the need for additional control devices. The throttle hole adaptively adjusts the opening size according to the pressure difference between the main air chamber and the secondary air chamber, thereby adjusting the size of the flow resistance. When the pressure difference just appears, the gas flow is prevented from suddenly changing, thereby ensuring that the performance of the pneumatic vibration isolator is more stable.

Description

Technical Field

[0001] The present invention relates to the technical field of air springs, and in particular to a pneumatic vibration isolator. Background Art

[0002] With the development of industries such as smartphones, the market demand for chips is increasing. Ultra-precision machining, as an indispensable link in the chip production and processing process, plays a very important role in obtaining chips with high shape accuracy and surface accuracy. Springs, as the most commonly used buffer devices, play a key role in vibration isolation in the ultra-precision machining link. Traditional coil springs are widely used in vibration isolation technology due to their simple structure, low cost, and easy production. However, due to the linear characteristics and non-adjustability of the coil spring stiffness, its effect on vibration isolation is limited and cannot meet the vibration isolation requirements required for precision machining. Especially for ultra-precision machining in the chip production process, due to the higher requirements for precision, the production and processing process has high requirements that are difficult for ordinary coil springs to fully meet.

[0003] While air springs have a higher cost than conventional coil springs, their overall performance is significantly superior. Air spring stiffness exhibits more ideal nonlinear characteristics, ensuring not only effective vibration isolation during severe vibrations but also precise machining during mild vibrations. However, conventional air springs also have limitations, such as a single design and the inability to dynamically adjust spring characteristics to suit varying operating conditions, which have limited their development to some extent.

[0004] Chinese invention patent CN109356955B discloses an air spring with multiple layers of additional air chambers for a hub-driven electric vehicle. The air spring comprises a main air chamber and an additional air chamber, wherein the main air chamber is a membrane-type flexible rubber airbag structure and the additional air chamber is a rigid multi-layer structure. The main air chamber and the additional air chamber are connected by a gas pipeline, and a throttle orifice with adjustable aperture is provided on the gas pipeline. The throttle damping orifice located on the gas pipeline has high-precision continuous adjustment capability. The rigid multi-layer additional air chamber is composed of multiple layers of cavities, and the different cavities are connected in series by switch valves. A controller can independently control the throttle damping orifice and the switch valve at the same time. By coordinating the control of the inner diameter of the throttle damping orifice and the opening and closing state of the switch valve, the stiffness and damping characteristics of the air spring can be precisely adjusted. However, on ultra-precision machining machines, there are certain limitations on the volume of air springs. Using an external auxiliary adjustment control device will make the air spring too large, which may not be well applied on machine tools. The performance of the air spring is adjusted by controlling the inner diameter of the throttling damping hole and the opening and closing state of the switch valve through a controller. There is no way to achieve adaptive adjustment of the performance of the air spring. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a pneumatic vibration isolator that does not require an external controller and solves the problem of excessive air spring volume.

[0006] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0007] A pneumatic vibration isolator includes a shell, a base plate, and a piston. The chamber enclosed by the shell and the piston is a main air chamber, and the cavity formed by the shell and the base plate is a secondary air chamber. A through hole is provided between the main air chamber and the secondary air chamber, and an adaptive adjustment damping component is provided in the through hole. A throttle hole is provided on the adaptive adjustment damping component.

[0008] The pneumatic vibration isolator's main and auxiliary air chambers are connected by a through-hole. An adaptive damping assembly is located within the through-hole. This adaptive damping assembly deforms according to actual operating conditions, enabling the orifice's inner diameter to change within a specific range, restricting the flow of gas and imparting air damping properties to the pneumatic vibration isolator. The main air chamber is a load-bearing component. The piston's extension and compression cause changes in the air pressure within the main chamber. This pressure change creates a pressure differential between the main and auxiliary chambers. Driven by this pressure differential, the gas within the pneumatic vibration isolator flows between the main and auxiliary chambers through the orifice. Varying the orifice's inner diameter can alter the mass flow rate of the gas between the two chambers. When gas passes through a small orifice, it restricts the flow, resulting in the pneumatic vibration isolator's pronounced air damping properties. Within a certain aperture range, the smaller the orifice's inner diameter, the greater the restriction, and the more pronounced the pneumatic vibration isolator's damping properties. This eliminates the need for manual regulation and eliminates external control devices such as controllers, effectively controlling the volume of the pneumatic vibration isolator to adapt to more application scenarios.

[0009] Furthermore, the shell is a metal shell, and the volume of the secondary air chamber is constant.

[0010] Furthermore, a rubber bag is provided between the piston and the housing. The chamber enclosed by the rubber bag and the housing is a main air chamber. The side of the rubber bag away from the auxiliary air chamber is connected to the piston.

[0011] Furthermore, the through hole includes a first through hole and a second through hole, one end of the first through hole is connected to the main air chamber, the other end of the first through hole is connected to the second through hole, and the end of the second through hole away from the first through hole is connected to the auxiliary air chamber, the diameter of the first through hole is larger than the diameter of the second through hole, and an annular table is provided at the position where the first through hole and the second through hole are connected.

[0012] Furthermore, the adaptive adjustment damping component includes a diaphragm, which is a membrane structure spliced ​​by several movable blades. A first circular hole is provided at the center of the diaphragm, and the side of the diaphragm facing the auxiliary air chamber is connected to the annular table in the through hole.

[0013] Furthermore, the diaphragm is made of rubber. In this way, the movable blade can deform according to actual working conditions, change the aperture of the first circular hole, and thus autonomously adjust the size of the throttle hole opening.

[0014] Optionally, the adaptive adjustment damping assembly includes a first baffle, a second baffle, a third baffle, and a fourth baffle arranged in sequence from top to bottom along the axial direction of the through hole, a second circular hole is provided at the center of the first baffle, the first baffle is connected to the outer edge of the first through hole, a third circular hole is provided at the center of the second baffle, the side of the second baffle away from the main air chamber is connected to the annular table in the through hole, the fourth baffle is connected to the outer edge of the second through hole, the third baffle is connected to the second baffle, and when the third baffle contacts the second baffle, the third baffle covers the third circular hole.

[0015] Furthermore, the first baffle and the second baffle are connected via a plurality of first springs, and the third baffle and the fourth baffle are connected via a plurality of second springs.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the inner diameter of the throttle hole can be directly adjusted through the adaptive adjustment of the damping component without the need for additional control devices, thereby solving the problem of volume limitation; the adaptive adjustment of the damping component can be adaptively adjusted in real time according to the working conditions, which is also more economical and environmentally friendly; the adaptive adjustment of the damping component can adaptively adjust the size of the throttle hole according to the pressure difference between the main air chamber and the auxiliary air chamber, thereby adjusting the size of the flow resistance, avoiding sudden changes in gas flow when the pressure difference just appears, and ensuring that the performance of the pneumatic vibration isolator is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a schematic structural diagram of the present invention in a first embodiment;

[0018] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0019] Figure 3 It is a schematic diagram of the structure of the diaphragm;

[0020] Figure 4 It is a schematic diagram of the deformation of the movable blade when the air pressure in the main air chamber is lower than the air pressure in the auxiliary air chamber;

[0021] Figure 5 It is a schematic diagram of the deformation of the movable blade when the air pressure in the main air chamber is greater than the air pressure in the auxiliary air chamber;

[0022] Figure 6 is a pressure difference-flow characteristic diagram in the first embodiment of the present invention;

[0023] Figure 7 is a diaphragm pressure distribution model in the first embodiment of the present invention;

[0024] Figure 8 It is a simplified mathematical model of the diaphragm deformation in the first embodiment of the present invention;

[0025] Figure 9 1 is a schematic structural diagram of the present invention in a second embodiment;

[0026] Figure 10 yes Figure 9 Enlarged view of point B in the middle;

[0027] Figure 11 is a top view of the first baffle;

[0028] Figure 12 is a top view of the second baffle;

[0029] Figure 13 is a top view of the third baffle;

[0030] Figure 14 is a top view of the fourth baffle;

[0031] Figure 15 is a schematic diagram of adaptively adjusting the deformation of the damping component when the air pressure in the main air chamber is lower than the air pressure in the auxiliary air chamber in the second embodiment;

[0032] Figure 16 It is a schematic diagram of adaptively adjusting the deformation of the damping component when the air pressure in the main air chamber is greater than the air pressure in the auxiliary air chamber in the second embodiment.

[0033] Description of reference numerals:

[0034] 1. Piston; 2. Rubber bag; 3. Main air chamber; 4. Adaptive damping assembly; 5. Housing; 6. Auxiliary air chamber; 7. Base plate; 8. Diaphragm; 801. Movable blade; 802. First circular hole; 9. First baffle; 901. Second circular hole; 10. First spring; 11. Second baffle; 1101. Third circular hole; 12. Third baffle; 13. Fourth baffle; 14. Second spring. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below with reference to the following embodiments. It should be noted that the embodiments and features of the embodiments may be combined unless they conflict. For ease of description, the words "upper," "lower," "left," and "right" appearing below merely indicate the directions of upper, lower, left, and right relative to the accompanying drawings and do not limit the structure.

[0036] Example 1

[0037] like Figure 1 As shown, a pneumatic vibration isolator includes a shell 5, a base plate 7, a piston 1, and a rubber bag 2. The chamber enclosed by the shell 5 and the rubber bag 2 is the main air chamber 3, and the cavity formed by the shell 5 and the base plate 7 is the auxiliary air chamber 6. A through hole is provided between the main air chamber 3 and the auxiliary air chamber 6. An adaptive adjustment damping component 4 is provided in the through hole. A throttle hole is provided on the adaptive adjustment damping component 4. The piston 1 is connected to the rubber bag 2. The shell 5 is a metal shell, and the volume of the auxiliary air chamber 6 is constant. The volume of the auxiliary air chamber 6 is larger than that of the main air chamber 3. The through hole includes a first through hole and a second through hole. One end of the first through hole is connected to the main air chamber 3, the other end of the first through hole is connected to the second through hole, and the end of the second through hole away from the first through hole is connected to the auxiliary air chamber 6. The diameter of the first through hole is larger than the diameter of the second through hole. An annular table is provided at the position where the first through hole and the second through hole are connected.

[0038] like Figure 2 and Figure 3 As shown, the adaptive adjustment damping component 4 includes a diaphragm 8, which is a membrane-type flexible rubber structure composed of several movable blades 801. The movable blades 801 are fan-shaped structures. A first circular hole 802 is provided at the center of the diaphragm 8. The diaphragm 8 is connected to the annular table in the through hole. The movable blades 801 are made of rubber and have a certain elasticity.

[0039] like Figure 4 and Figure 5 As shown, when the pneumatic vibration isolator is in its inoperative state, the movable blade 801 remains horizontal, and the throttle orifice is at a set and constant size. When the piston 1 stretches the rubber bladder 2, the pressure in the secondary air chamber 6 becomes higher than that in the main air chamber 3. When the pneumatic vibration isolator begins to operate and function, the movable blade 8 deforms toward the main air chamber 3, causing air to flow from the secondary air chamber 6 to the main air chamber 3. The greater the pressure difference between the secondary air chamber 6 and the main air chamber 3, the greater the deformation of the movable blade 801, the larger the throttle orifice diameter, and the smaller the flow resistance. When the piston 1 squeezes the rubber bladder 2, the pressure in the main air chamber 3 becomes higher than that in the secondary air chamber 6. The movable blade 801 deforms toward the secondary air chamber 6, causing air to flow from the main air chamber 3 to the secondary air chamber 6. The greater the pressure difference between the main air chamber 3 and the secondary air chamber 6, the greater the deformation of the movable blade 801, the larger the throttle orifice diameter, and the smaller the flow resistance. The movable blade 801 can deform according to actual operating conditions, autonomously adjusting the size of the throttle orifice opening.

[0040] like Figure 7As shown in Figure 1, when the pressures of the main air chamber 3 and the auxiliary air chamber 6 are different and a pressure difference occurs, the entire diaphragm 8 is affected by the air pressure, and the pressure distribution model can be simplified to a uniform load acting on the diaphragm. The diaphragm 8 is deformed under pressure, and its simplified mathematical model is as follows: Figure 8 As shown:

[0041] According to material mechanics and mathematical knowledge, we can calculate:

[0042]

[0043] Where r is the equivalent throttle radius increment, L is the length of the movable blade deformed in the radial direction, ΔP is the pressure difference between the upstream and downstream of the throttle, and H is the bending stiffness of the material.

[0044] Therefore, the equivalent orifice area is:

[0045]

[0046] in, is the initial radius of the throttle hole.

[0047] According to Bernoulli's equation, the mass flow rate through the orifice is:

[0048]

[0049] Where G is the mass flow rate of gas, S e is the area through which the air flows, p1 and p2 are the upstream and downstream pressures, T1 and T2 are the upstream and downstream absolute temperatures, R is the gas constant, and k is the specific heat of air.

[0050] Substituting the equivalent throttle area formula into the equation, we can get the mass flow rate flowing through the throttle hole:

[0051]

[0052] From the above formula, the simulation diagram of the relationship between the mass flow rate of the ordinary throttle airflow and the pressure difference between the main and auxiliary air chambers is as follows: Figure 6 As shown in the middle curve b: After the throttle hole diameter is set, the throttle area S e The pressure difference remains unchanged at all times. As the pressure difference increases, the air flow rate also increases. When the pressure difference is small, the flow rate changes rapidly with the change of the pressure difference. Especially when the pressure difference fluctuates around 0kPa, the flow rate will change dramatically in an instant, which will have a great impact on the performance of the pneumatic vibration isolator.

[0053] The adaptive damping component of the present invention has a variable orifice size that changes with the pressure difference. When a pressure difference appears between the main and auxiliary air chambers, the orifice size will increase accordingly. At this time, the area through which the airflow flows increases, and the amount of air flowing through the orifice increases. When the pressure difference fluctuates around 0kPa, the rate at which the mass flow changes with the pressure difference decreases. In this case, the flow rate does not change significantly in an instant, making the performance of the pneumatic vibration isolator more stable. The simulation diagram of the relationship between the airflow mass flow and the pressure difference between the main and auxiliary air chambers is shown as follows: Figure 6 As shown in the simulation data curve a, Figure 6 In the figure, c is the experimental data point. It can be found from the figure that the change trend of the simulation data curve a is basically consistent with that of the experimental data point c.

[0054] Example 2

[0055] like Figure 9 As shown, a pneumatic vibration isolator includes a shell 5, wherein the upper portion of the shell 5 is provided with a first groove opening upward, and the lower portion of the shell 5 is provided with a second groove opening downward. The chamber enclosed by the first groove and the rubber bladder 2 is the main air chamber 3, and the chamber formed by the second groove and the bottom plate 7 is the auxiliary air chamber 6. A through hole is provided between the main air chamber 3 and the auxiliary air chamber 6, and an adaptive adjustment damping component 4 is provided in the through hole. The side of the rubber bladder 2 away from the main air chamber 3 is connected to the piston 1. The through hole facing the main air chamber 3 is the first through hole, and the through hole facing the auxiliary air chamber 6 is the second through hole. The diameter of the first through hole is larger than the diameter of the second through hole, and an annular table is provided at the position where the first through hole and the second through hole are connected. The shell 5 is a metal shell, and the volume of the auxiliary air chamber 6 is constant.

[0056] like Figure 10 As shown, the throttling damping orifice assembly 4 includes a first baffle 9, a second baffle 11, a third baffle 12, and a fourth baffle 13, which are arranged in order from top to bottom along the axial direction of the through hole. The first baffle 9 has a second circular hole at its center, and the first baffle 9 is connected to the outer edge of the first through hole. The second baffle 11 has a third circular hole at its center. The side of the second baffle 11 away from the main air chamber 3 is connected to the annular table in the through hole. The fourth baffle 13 is connected to the outer edge of the second through hole. The third baffle 12 is connected to the second baffle 11, and the third baffle 12 closes the third circular hole. The first baffle 9 and the second baffle 11 are connected by a plurality of first springs 10, and the third baffle 12 and the fourth baffle 13 are connected by a plurality of second springs 14.

[0057] like Figure 11 and Figure 12As shown, a second circular hole 901 is defined at the center of the first baffle 9, leaving a gap between the first baffle 9 and the edge of the through-hole. A connecting plate with holes is symmetrically positioned on the first baffle 9, connecting the first baffle 9 to the outer wall of the first through-hole via screws. A third circular hole 1101 is defined at the center of the second baffle 11. The second and third circular holes 901 and 1101 have the same diameter, and the outer diameters of the first and second baffles 9 and 11 are the same.

[0058] like Figure 13 、 Figure 14 As shown, the third baffle 12 is a circular baffle with a diameter greater than that of the third circular hole. When the second baffle 11 abuts the third baffle 12, the third baffle 12 completely closes the third circular hole. A connecting plate with a hole is symmetrically arranged along the edge of the fourth baffle 13. The connecting plate connects the fourth baffle 13 to the outer wall of the second through hole via screws, leaving a gap between the fourth baffle 13 and the edge of the through hole. The diameter of the third baffle 12 is the same as that of the fourth baffle 13.

[0059] like Figure 15 and Figure 16 As shown, when the pneumatic isolator is not operating, the first spring 10 and the second spring 14 are at a set length, and the first baffle 9, the second baffle 11, the third baffle 12, and the fourth baffle 13 are all in set positions. The adaptive damping assembly is equivalent to a state without a throttle hole and remains constant. When the piston 1 stretches the rubber bag 2, the air pressure in the auxiliary air chamber 6 is higher than that in the main air chamber 3. The first spring 10 is compressed and deformed, shortening in length. The second spring 14 is tensile and deformed, lengthening in length. The second baffle 11 and the third baffle 12 move upward together, leaning against the main air chamber 3. Air flows from the auxiliary air chamber 6 to the main air chamber 3. The greater the pressure difference between the auxiliary air chamber 6 and the main air chamber 3, the greater the spring deformation, the larger the equivalent throttle hole diameter, and the smaller the flow resistance. When the piston 1 squeezes the rubber bladder 2, the pressure in the main air chamber 3 rises above that in the auxiliary air chamber 6. The second spring 14 deforms under pressure, shortening its length. The second baffle 11 remains in a restricted position, while the third baffle 12 moves downward, leaning toward the auxiliary air chamber 6. Air flows from the main air chamber 3 through the third circular hole 1101 in the second baffle 11 to the auxiliary air chamber 6. The airflow is determined by the volume between the second baffle 11 and the third baffle 12. The greater the pressure difference between the main air chamber 3 and the auxiliary air chamber 6, the greater the spring deformation, the larger the equivalent throttle orifice diameter, and the lower the flow resistance. The baffle can compress either the first spring 10 or the second spring 14 based on the pressure difference between the main air chamber 3 and the auxiliary air chamber 6, thereby adaptively adjusting the size of the equivalent throttle orifice opening.

[0060] Example 1 is a preferred embodiment of the present invention. Both Example 1 and Example 2 can achieve the effect of the throttle orifice size being variable with the pressure difference. After a pressure difference occurs between the main and auxiliary air chambers, the throttle orifice size will increase accordingly. At this time, the area through which the airflow flows increases, and the amount of air flowing through the throttle orifice increases. However, compared to Example 2, the throttle damping orifice assembly proposed in Example 1 has a simpler structure, lower manufacturing and maintenance costs, is less prone to failure, and has less hysteresis in its adaptive adjustment, making the movement process more stable. In summary, Example 1 has a better adaptive adjustment effect.

[0061] The contents illustrated in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications of the present invention by those skilled in the art shall fall within the scope defined by the claims attached to this application.

Claims

1. A pneumatic vibration isolator comprising a housing (5), a base plate (7), and a piston (1), characterized in that: The chamber enclosed by the housing (5) and the piston (1) is the main air chamber (3), and the chamber formed by the housing (5) and the base plate (7) is the auxiliary air chamber (6). A through hole is provided between the main air chamber (3) and the auxiliary air chamber (6), and an adaptively adjustable damping component (4) is provided in the through hole. A throttle hole is provided on the adaptively adjustable damping component (4); The through hole comprises a first through hole and a second through hole, one end of the first through hole is in communication with the main air chamber (3), the other end of the first through hole is in communication with the second through hole, and one end of the second through hole away from the first through hole is in communication with the auxiliary air chamber (6), and an annular table is provided at the connection position between the first through hole and the second through hole; The adaptive adjustment damping component (4) comprises a first baffle (9), a second baffle (11), a third baffle (12), and a fourth baffle (13) which are arranged in sequence from top to bottom along the axial direction of the through hole, wherein a second circular hole (901) is provided at the center of the first baffle (9), and the first baffle (9) is connected to the outer edge of the first through hole, a third circular hole (1101) is provided at the center of the second baffle (11), a side of the second baffle (11) away from the main air chamber (3) is connected to the annular table in the through hole, the fourth baffle (13) is connected to the outer edge of the second through hole, the third baffle (12) is connected to the second baffle (11), and when the third baffle (12) contacts the second baffle (11), the third baffle (12) covers the third circular hole (1101).

2. A pneumatic vibration isolator according to claim 1, characterized in that: The housing (5) is a metal housing, and the volume of the auxiliary air chamber (6) is constant.

3. The pneumatic vibration isolator according to claim 2, characterized in that: A rubber bag (2) is provided between the piston (1) and the housing (5); the chamber enclosed by the rubber bag (2) and the housing (5) is a main air chamber (3); and the side of the rubber bag (2) away from the auxiliary air chamber (6) is connected to the piston (1).

4. A pneumatic vibration isolator according to claim 3, characterized in that: The diameter of the first through hole is greater than the diameter of the second through hole.

5. A pneumatic vibration isolator according to any one of claims 1 to 4, characterized in that: The first baffle (9) and the second baffle (11) are connected via a plurality of first springs (10), and the third baffle (12) and the fourth baffle (13) are connected via a plurality of second springs (14).

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