Air floatation supporting structure for vibration reduction of crystal oscillator and design method

Abstract

The invention relates to the technical field of vibration reduction of crystal oscillators, and particularly discloses an air floatation supporting structure for vibration reduction of a crystal oscillator and a design method. The air floatation supporting structure comprises a piston body used for installing the crystal oscillator, a sleeve which is arranged on the outer side of the piston body in a sleeving mode and is coaxially arranged, and an auxiliary air chamber installed at the bottom of the sleeve. And high-pressure gas in the auxiliary gas chamber enters the sleeve and applies upward acting force to the piston body, so that the piston body and the crystal oscillator on the piston body are stably suspended. The rigidity is reduced through the auxiliary air chamber, the piston body and the crystal oscillator on the piston body are suspended through high-pressure air, and therefore isolation of low-frequency vibration of the crystal oscillator is effectively achieved; therefore, the problems of crystal oscillator frequency drift and phase noise deterioration caused by low-frequency vibration are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal oscillator vibration reduction, and more specifically, to an air-floating support structure and a design method for crystal oscillator vibration reduction. Background Art

[0002] The core component of the crystal oscillator is the piezoelectric crystal, which generates resonance through the mutual conversion between mechanical energy and electrical energy to achieve stable frequency output. In the above application fields, vibration is inevitable. Based on the working principle of the crystal oscillator, vibration will directly cause the frequency drift and phase noise deterioration of the crystal oscillator output signal. Studies have shown that the phase noise deterioration value caused by vibration is between 10dB-50dB, which directly causes the system to not work properly.

[0003] At present, the vibration frequency range of crystal oscillators is mainly 10Hz-2000Hz. The widely used methods such as wire rope vibration absorbers and rubber vibration absorbers have good vibration reduction effects on medium and high frequency vibrations above 200Hz, but they are far from meeting the stringent requirements of equipment for crystal oscillators in terms of stability, accuracy and purity.

[0004] The problem of crystal oscillator frequency drift and phase noise degradation caused by low-frequency vibration has become an extremely important bottleneck problem restricting the improvement of electronic equipment system performance. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an air-floating support structure and a design method for crystal oscillator vibration reduction;

[0006] The solution adopted by the present invention to solve the technical problem is:

[0007] An air-floating support structure for crystal oscillator vibration reduction comprises a piston body for mounting the crystal oscillator, a sleeve sleeved outside the piston body and coaxially arranged, and an auxiliary air chamber mounted at the bottom of the sleeve; high-pressure gas in the auxiliary air chamber enters the sleeve and applies an upward force to the piston body, so that the piston body and the crystal oscillator on the piston body are stably suspended.

[0008] In some possible implementations, the piston body includes a main body which is sleeved in a sleeve and has a concave cavity, and a support plate which is installed on the top of the main body and located on the top of the sleeve; a gap is formed between the outer side of the main body and the inner side of the sleeve.

[0009] In some possible implementations, a plurality of groups of through holes are evenly arranged on the body and along its circumference, and each group of through holes is respectively connected to the concave cavity and the gap.

[0010] In some possible implementations, the sleeve includes a cylinder sleeved on the outside of the main body, and a bottom plate installed at the bottom of the cylinder and cooperating with the cylinder to form a mounting cavity; an air inlet hole connected to the auxiliary air chamber is provided on the bottom plate.

[0011] In some possible implementations, the auxiliary air chamber is provided with an inlet hole connected to a high-pressure air source.

[0012] A design method for an air-floating support structure for crystal vibration reduction based on the above, based on vibration isolation theory, when the excitation frequency is greater than The vibration isolation system can only exert its vibration isolation performance when it is times the natural frequency of the system; the ultra-low stiffness characteristics of the air floating support structure are used to reduce the natural frequency of the entire system and achieve vibration reduction for the crystal oscillator.

[0013] In some possible implementations, the following steps are specifically included:

[0014] Step S1: in the working state, when the entire device is disturbed by the external environment, the motion equation of the entire device is calculated; the disturbances to which the crystal oscillator, the piston body, and the mass block formed by the connecting member for the crystal oscillator and the piston body are subjected are calculated;

[0015] Step S2: Calculate the natural frequency under undamped conditions, calculate the damping ratio, and calculate the gain and limit of the entire device;

[0016] Step S3: Calculate the ideal gas state equation of the entire device to obtain the stiffness.

[0017] In some possible implementations, the step S1 specifically includes:

[0018] Step S11: Calculate the disturbance of the external environment:

[0019] y(t)=|Y|sinωt (1-1);

[0020] |Y| is the amplitude of the external disturbance;

[0021] Step S12: Obtain the motion equation of the entire device (1-2):

[0022]

[0023] We can get: x(t) = |X|sinωt (1-3);

[0024] Where m is the mass of the mass block;

[0025] x(t) is the disturbance of the mass block;

[0026] c is the damping coefficient;

[0027] k is the stiffness;

[0028] |X| is the amplitude of the mass block; is the mass speed; is the acceleration of the mass; is the external disturbance acceleration;

[0029] Step S13: Combine equations (1-1), (1-2), and (1-3) to calculate the disturbance to which the mass block is subjected:

[0030]

[0031] Where i is the imaginary unit;

[0032] t is time;

[0033] ω is the angular frequency.

[0034] In some possible implementations, step S2 specifically refers to:

[0035] Step S21: Define the natural frequency and damping ratio under undamped conditions:

[0036]

[0037]

[0038] Where ω n is the natural frequency of the system under undamped conditions;

[0039] ξ is the damping ratio;

[0040] Step S22: Combine equations (1-4), (1-5), and (1-6) to obtain:

[0041]

[0042]

[0043]

[0044] Among them, H A is the system gain;

[0045] is the system phase.

[0046] In some possible implementations, step S3 specifically includes:

[0047] Step S31: Calculation During the working process, the entire device approximately satisfies the ideal gas state equation:

[0048] (p0+p a )V0=(p+p a )V(1-10);

[0049] Where p0 is the initial pressure;

[0050] pa is the atmospheric pressure;

[0051] V0 is the initial volume of the replicated air chamber;

[0052] p is the pressure after the change;

[0053] V is the volume of the auxiliary air chamber after change;

[0054] Step S32: Obtain the force equation during the working process:

[0055] F = ps(1-11);

[0056] Wherein, F is the supporting force of the air flotation device;

[0057] S is the pressure area;

[0058] Step S33: define stiffness:

[0059]

[0060] From formula (1-10), (1-11) and (1-12), we can get:

[0061]

[0062] Step S34: During the working process, the effective bearing area of ​​the entire device remains unchanged, and it can be obtained that:

[0063]

[0064]

[0065] Therefore, we can get:

[0066]

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] The present invention provides an auxiliary air chamber and suspends the piston body and the crystal oscillator on the piston body through high-pressure gas, thereby effectively isolating the low-frequency vibration of the crystal oscillator; and further effectively solving the crystal oscillator frequency drift and phase noise deterioration caused by low-frequency vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a schematic diagram of the structure of the present invention;

[0070] Figure 2 It is a working state diagram of the present invention;

[0071] Figure 3 is an equivalent schematic diagram of step S11 in the present invention;

[0072] Figure 4 It is the stiffness simulation diagram of the present invention;

[0073] Among them: 1. piston body; 11. main body; 12. support plate; 13. connecting piece; 111. through hole; 2. sleeve; 21. cylinder body; 22. bottom plate; 221. air inlet hole; 3. auxiliary air chamber; 10. crystal oscillator. DETAILED DESCRIPTION

[0074] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. The "first", "second" and similar words mentioned in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "one" or "one" and other similar words do not indicate a quantity restriction, but indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more. For example, multiple positioning columns refer to two or more positioning columns. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] The present invention is described in detail below.

[0076] like Figure 1-Figure 4 As shown:

[0077] An air-floating support structure for vibration reduction of a crystal oscillator 10 comprises a piston body 1 for mounting the crystal oscillator 10, a sleeve 2 which is sleeved outside the piston body 1 and coaxially arranged, and an auxiliary air chamber 3 which is installed at the bottom of the sleeve 2; the high-pressure gas in the auxiliary air chamber 3 enters the sleeve 2 and applies an upward force to the piston body 1, so that the piston body 1 and the crystal oscillator 10 on the piston body 1 are stably suspended; the piston body 1 comprises a body 11 which is sleeved in the sleeve 2 and has a concave cavity, a support plate 1 which is installed on the top of the body 11 and is located on the top of the sleeve 2 2; a gap is formed between the outer side of the body 11 and the inner side of the sleeve 2; a plurality of groups of through holes 111 are evenly arranged on the body 11 and along its circumference, and each group of through holes 111 is connected to the concave cavity and the gap respectively; the sleeve 2 includes a cylinder 21 which is sleeved on the outer side of the body 11, and a bottom plate 22 which is installed at the bottom of the cylinder 21 and cooperates with the cylinder 21 to form a mounting cavity; an air inlet 221 connected to the auxiliary air chamber 3 is arranged on the bottom plate 22; the auxiliary air chamber 3 is provided with an inlet hole connected to the high-pressure air source.

[0078] When in use, the crystal oscillator 10 is mounted on the support plate 12 by means of bolts and other connectors, and the axis of the crystal oscillator 10 is made coaxial with the axis of the support plate 12; then, high-pressure gas is delivered to the auxiliary air chamber 3 through a high-pressure gas source, and the high-pressure gas enters the concave cavity and the gap through the air inlet 221, exerting a force acting on the piston body 1 to move upward, and the high-pressure gas is slowly pressurized, so that a gas discharge gap is formed between the support plate 12 and the top surface of the sleeve 2. At this time, the high-pressure gas is no longer pressurized, and the high-pressure gas is discharged from the gas discharge gap. The crystal oscillator 10 on the piston body 1 will be suspended when the high-pressure gas with stable pressure is continuously input;

[0079] The auxiliary air chamber 3 is provided to make the entire air-floating support structure have low rigidity characteristics, thereby isolating the low-frequency vibration of the crystal oscillator 10 .

[0080] A design method for an air-floating support structure for vibration reduction of a crystal oscillator 10 according to the above, based on vibration isolation theory, when the excitation frequency is greater than The vibration isolation system can only play its vibration isolation performance when the natural frequency of the system is greater than 10 times; the ultra-low stiffness characteristics of the air-floating support structure are used to reduce the natural frequency of the entire system and achieve 10 vibration reduction for the crystal oscillator; specifically, the following steps are included:

[0081] Step S1: in the working state, when the entire device is disturbed by the external environment, the motion equation of the entire device is calculated; the disturbances to which the crystal oscillator 10, the piston body 1, and the mass block formed by the connecting member for the crystal oscillator 10 and the piston body 1 are subjected are calculated;

[0082] In some possible implementations, the step S1 specifically includes:

[0083] Step S11: According to Figure 3 , in the working state, the gas path of high pressure gas is as follows Figure 2 As shown; when the entire device is affected by the external environment, the crystal oscillator 10, bolts, and piston are equivalent to a mass block with a mass of m, and the rest of the parts are equivalent to elastic supports with a damping coefficient of c and a stiffness of k. The disturbance of the external environment is calculated:

[0084] y(t)=|Y|sinωt (1-1);

[0085] |Y| is the amplitude of the external disturbance;

[0086] Step S12: Obtain the motion equation of the entire device (1-2):

[0087]

[0088] We can get: x(t) = |X|sinωt (1-3);

[0089] Where m is the mass of the mass block;

[0090] x(t) is the disturbance of the mass block;

[0091] c is the damping coefficient;

[0092] k is the stiffness;

[0093] |X| is the amplitude of the mass block; is the mass speed; is the acceleration of the mass; is the external disturbance acceleration;

[0094] Step S13: Combine equations (1-1), (1-2), and (1-3) to calculate the disturbance to which the mass block is subjected:

[0095]

[0096] Where i is the imaginary unit;

[0097] t is time;

[0098] ω is the angular frequency.

[0099] Step S2: Calculate the natural frequency under undamped conditions, calculate the damping ratio, and calculate the gain and limit of the entire device; Step S2 specifically refers to:

[0100] Step S2: Calculate the natural frequency under undamped conditions, calculate the damping ratio, and calculate the gain and limit of the entire device;

[0101] Step S3: Calculate the ideal gas state equation of the entire device to obtain the stiffness.

[0102] Step S21: Define the natural frequency and damping ratio under undamped conditions:

[0103]

[0104]

[0105] Where ω n is the natural frequency of the system under undamped conditions;

[0106] ξ is the damping ratio;

[0107] Step S22: Combine equations (1-4), (1-5), and (1-6) to obtain:

[0108]

[0109]

[0110]

[0111] Among them, H A is the system gain;

[0112] is the system phase.

[0113] From formula (1-8), it can be seen that reducing the natural frequency of the device is a necessary means to isolate low-frequency vibrations; from formula 1-5, it can be seen that reducing the mass or reducing the system stiffness can reduce the natural frequency of the system; since the crystal oscillator 10 is a supported object, the natural frequency of the system cannot be reduced by reducing its mass, so reducing the stiffness of the device is the main measure to isolate the low-frequency vibrations of the crystal oscillator 10.

[0114] Step S3: Calculate the ideal gas state equation of the entire device to obtain stiffness. Step S3 specifically includes:

[0115] Step S31: Calculation During the working process, the entire device approximately satisfies the ideal gas state equation:

[0116] (p0+p a )V0=(p+p a )V(1-10);

[0117] Where p0 is the initial pressure;

[0118] p a is the atmospheric pressure;

[0119] V0 is the initial volume of the replicated air chamber;

[0120] p is the pressure after the change;

[0121] V is the volume of the auxiliary air chamber 3 after the change;

[0122] Step S32: Obtain the force equation during the working process:

[0123] F = ps(1-11);

[0124] F is the supporting force of the air flotation device;

[0125] S is the pressure area;

[0126] Step S33: define stiffness:

[0127]

[0128] From formula (1-10), (1-11) and (1-12), we can get:

[0129]

[0130] Step S34: During the working process, the effective bearing area of ​​the entire device remains unchanged, and it can be obtained that:

[0131]

[0132]

[0133] Therefore, we can get:

[0134]

[0135] It can be concluded that the air-floating support structure has a low stiffness characteristic, and the stiffness of the system can be further reduced by increasing the volume of the auxiliary air chamber 3. Its stiffness simulation characteristics are as follows: Figure 4 shown.

[0136] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. An air-floating support structure for crystal oscillator vibration reduction, characterized in that: It includes a piston body for installing a crystal oscillator, a sleeve sleeved outside the piston body and coaxially arranged, and an auxiliary air chamber installed at the bottom of the sleeve; high-pressure gas in the auxiliary air chamber enters the sleeve and applies an upward force to the piston body, so that the piston body and the crystal oscillator on the piston body are stably suspended.

2. The air-floating support structure for crystal oscillator vibration reduction according to claim 1, characterized in that: The piston body comprises a main body which is sleeved in a sleeve and has a concave cavity, and a support plate which is installed on the top of the main body and located on the top of the sleeve; a gap is formed between the outer side of the main body and the inner side of the sleeve.

3. The air-floating support structure for crystal oscillator vibration reduction according to claim 2, characterized in that: A plurality of groups of through holes are evenly arranged on the body along its circumference, and each group of through holes is communicated with the concave cavity and the gap respectively.

4. The air-floating support structure for crystal oscillator vibration reduction according to claim 1, characterized in that: The sleeve comprises a cylinder sleeved on the outside of the main body, and a bottom plate installed at the bottom of the cylinder and cooperating with the cylinder to form a mounting cavity; an air inlet hole communicating with the auxiliary air chamber is arranged on the bottom plate.

5. The air-floating support structure for crystal oscillator vibration reduction according to claim 1, characterized in that: The auxiliary air chamber is provided with an inlet hole connected with a high-pressure air source.

6. A method for designing an air-floating support structure for crystal oscillator vibration reduction according to any one of claims 1 to 5, characterized in that: Based on vibration isolation theory, when the excitation frequency is greater than The vibration isolation system can only exert its vibration isolation performance when it is times the natural frequency of the system; the ultra-low stiffness characteristics of the air floating support structure are used to reduce the natural frequency of the entire system and achieve vibration reduction for the crystal oscillator.

7. The design method of an air-floating support structure for crystal oscillator vibration reduction according to claim 6, characterized in that: The specific steps include: Step S1: in the working state, when the entire device is disturbed by the external environment, the motion equation of the entire device is calculated; the disturbances to which the crystal oscillator, the piston body, and the mass block formed by the connecting member for the crystal oscillator and the piston body are subjected are calculated; Step S2: Calculate the natural frequency under undamped conditions, calculate the damping ratio, and calculate the gain and limit of the entire device; Step S3: Calculate the ideal gas state equation of the entire device to obtain the stiffness.

8. The design method of an air-floating support structure for crystal oscillator vibration reduction according to claim 7, characterized in that: The step S1 specifically includes: Step S11: Calculate the disturbance of the external environment: y(t)=|Y|sinωt (1-1); |Y| is the amplitude of the external disturbance; Step S12: Obtain the motion equation of the entire device (1-2): We can get: x(t) = |X|sinωt (1-3); Where m is the mass of the mass block; x(t) is the disturbance of the mass block; c is the damping coefficient; k is the stiffness; X| is the amplitude of the mass block; is the mass speed; is the acceleration of the mass; is the external disturbance acceleration; Step S13: Combine equations (1-1), (1-2), and (1-3) to calculate the disturbance to which the mass block is subjected: Where i is the imaginary unit; t is time; ω is the angular frequency.

9. The design method of an air-floating support structure for crystal oscillator vibration reduction according to claim 8, characterized in that: The step S2 specifically refers to: Step S21: Define the natural frequency and damping ratio under undamped conditions: Where ω n is the natural frequency of the system under undamped conditions; ξ is the damping ratio; Step S22: Combine equations (1-4), (1-5), and (1-6) to obtain: Among them, H A is the system gain; System phase.

10. The design method of an air-floating support structure for crystal oscillator vibration reduction according to claim 9, characterized in that: The step S3 specifically includes: Step S31: Calculation During the working process, the entire device approximately satisfies the ideal gas state equation: (p0+p a )V0=(p+p a )V(1-10); Where p0 is the initial pressure; p a is the atmospheric pressure; V0 is the initial volume of the replicated air chamber; p is the pressure after the change; V is the volume of the auxiliary air chamber after change; Step S32: Obtain the force equation during the working process: F = ps(1-11); Wherein, F is the supporting force of the air flotation device; S is the pressure area; Step S33: define stiffness: From formula (1-10), (1-11) and (1-12), we can get: Step S34: During the working process, the effective bearing area of ​​the entire device remains unchanged, and it can be obtained that: Therefore, we can get:

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