A low frequency detector with high precision and high stability

Abstract

The invention proposes a low-frequency geophone with high precision and high stability, comprising a shell; a magnetic system, comprising an upper magnetic shoe, a magnet and a lower magnetic shoe which are sequentially installed in the shell from top to bottom; the magnetic system and the shell form a closed magnetic field; an inertial body, comprising and a detection circuit, which is used to detect the movement of the inertial body and cut the induction signal generated by the closed magnetic field and output it; the size of the upper magnetic shoe or the lower magnetic shoe is optimized to meet the following formula: Ld×F2=Lz×F1; in the formula, Ld represents a power arm, which is the length of the elastic element sample in the inertial body; Lz represents a resistance arm, which is the difference between the end face outer diameter and the end face inner diameter of the upper magnetic shoe or the lower magnetic shoe; F1 represents the elastic force of the resistance arm; F2 represents the mass of the inertial body; and the problem of seeking the balance of the geophone vibration system and achieving lower frequency capture when the geophone is captured at a low frequency is solved while satisfying the small-volume core body and the elastic force of the spring sheet resistance arm remains unchanged and the mass of the inertial body is improved.

Description

Technical Field

[0001] The present invention relates to the field of detectors, and in particular to a low-frequency detector with high precision and high stability. Background Art

[0002] As we all know, in the field of exploration and engineering vibration measurement, the application of low-frequency detectors is becoming more and more extensive, and the demand is increasing. From the perspective of market demand, everyone hopes that the natural frequency of the detector is as low as possible and the frequency band is as wide as possible.

[0003] The technicians in this field have achieved a lower natural frequency by increasing the inertial weight of the detector and designing the pattern (pattern) of the detector spring. However, the above measures naturally lead to an increase in the volume of the low-frequency detector, and the resulting imbalance of the structure and mechanical system will inevitably emerge. The specific manifestation is that the detector frequency and distortion are large and unstable, which affects the acquisition effect of the detector and limits its wide-scale promotion and use.

[0004] In addition, the core of the detector has formed an industry consensus, and 25mm and 35mm diameters are usually used as standardized sizes. When changing the power arm Ld to achieve low-frequency response, the variable space is limited by the core diameter and the size change cannot be achieved. That is, it is quite difficult to increase the power arm Ld within the small volume of the standard size. According to the natural frequency formula of the elastic element, it can be known that increasing the gravity F2 of the inertial body can also reduce the natural frequency, which has a great relationship with the inertial body skeleton material. When the inertial body skeleton material is selected to use aluminum alloy material, the natural frequency of the entire detector core can be reduced to 4.5Hz; when the inertial body skeleton material is selected to use high-density paramagnetic and paramagnetic conductive materials such as copper and copper alloys, the natural frequency of the entire detector core can be reduced to 3Hz; and the theoretical density of copper and copper alloys is more than 3 times that of aluminum alloys, which means that the increase in the gravity of the inertial body will reduce the natural frequency that can be captured by the detector.

[0005] The limitation of using a small core of standard size means that the power arm cannot be further increased, but the exponential increase in the gravity of the inertial body will cause the elastic force of the resistance arm to increase exponentially, causing the balance of the detector vibration system to be broken, causing the spring sheet to move axially and radially during operation, resulting in the detector frequency and distortion becoming larger and the stability becoming worse; therefore, it is also necessary to ensure that the elastic force of the spring sheet resistance arm remains unchanged to prevent it from moving axially and radially.

[0006] In summary, the problem that needs to be solved is to make the existing detector meet the three restrictive conditions of the small volume core (i.e., the power arm Ld) remaining basically unchanged, the inertial weight (i.e., F2 increasing), and the elastic force of the resistance arm of the spring sheet itself (i.e., F1) remaining unchanged, while also meeting the balance of the detector vibration system and achieving capture of lower frequencies. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a low-frequency detector with high precision and high stability, which solves the problem of optimizing the low-frequency capture of the detector while satisfying the requirement of maintaining the elastic force of the small-volume core and the spring resistance arm unchanged, and seeking the balance of the detector vibration system and achieving lower frequency capture while increasing the inertial weight.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A low-frequency detector with high precision and high stability, comprising:

[0010] case;

[0011] The magnetic system comprises an upper magnetic shoe, a magnet and a lower magnetic shoe which are sequentially installed in the housing from top to bottom;

[0012] The magnetic system and the shell form a closed magnetic field;

[0013] Inertial bodies, including and

[0014] A detection circuit, used for detecting the movement of the inertial body and cutting the induction signal generated by the closed magnetic field and outputting it;

[0015] The size optimization of the upper magnetic shoe or the lower magnetic shoe satisfies the following formula:

[0016] Ld×F2=Lz×F1

[0017] In the formula,

[0018] Ld represents the power arm, which is the length of the elastic element sample in the inertial body;

[0019] Lz represents a resistance arm, which is the difference between the outer diameter and the inner diameter of the end face of the upper magnetic shoe or the lower magnetic shoe;

[0020] F1 represents the elastic force of the resistance arm;

[0021] F2 represents the gravity of the inertial body.

[0022] Preferably, the inertial body comprises an upper wire rack, a connecting sleeve and a lower wire rack which are sequentially connected and installed in the housing from top to bottom;

[0023] An upper coil is wound on the upper wire rack;

[0024] A lower coil is wound on the lower coil rack, and an outlet end of the lower coil is connected to an outlet end of the upper coil;

[0025] A weight adjustment coil is wound around the connection position between the connecting sleeve and the upper wire rack and the lower wire rack;

[0026] The upper end of the upper wire rack is provided with a first spring sheet and a second spring sheet in sequence, and is fixed by an upper retaining spring;

[0027] The third spring sheet and the fourth spring sheet are sequentially installed at the lower end of the lower wire frame and are limited and fixed by a lower clamping spring.

[0028] Preferably, an insulating sheet is provided between the first spring sheet, the second spring sheet and the upper magnetic shoe.

[0029] Preferably, the detection circuit includes a circuit board mounted on the housing, and a first terminal and a second terminal fixed on the circuit board;

[0030] The first terminal is electrically connected to the magnetic system via an upper inner contact spring sheet, and the magnetic system is electrically connected to the third spring sheet and the fourth spring sheet;

[0031] The first spring sheet and the second spring sheet are electrically connected to the upper coil;

[0032] The third spring sheet and the fourth spring sheet are electrically connected to the lower coil;

[0033] The second terminal is electrically connected to the first spring piece and the second spring piece via an upper external contact spring piece.

[0034] Preferably, an upper contact gasket is provided between the first spring sheet and the second spring sheet.

[0035] Preferably, an upper gasket is provided between the first spring sheet and the upper retaining spring.

[0036] Preferably, a lower contact gasket is provided between the third spring sheet and the fourth spring sheet.

[0037] Preferably, a lower gasket is provided between the fourth spring sheet and the lower retaining spring.

[0038] Preferably, the housing comprises:

[0039] shell;

[0040] An upper cover, mounted on the upper end of the housing and used to connect and fix the upper magnetic shoe;

[0041] A lower top cover is installed at the lower end of the shell and is used to connect and fix the lower magnetic shoe.

[0042] Preferably, the value range of Lz is 9mm~13mm.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. By constructing a new balance formula for the detector vibration system, the inertial weight and the resistance arm (the difference between the inner and outer diameters of the magnetic shoe end face) are linked. When the inertial weight is increased, the resistance arm Lz is adaptively changed, which can not only meet the existing standardized size and small volume core installation, but also enable the elastic element to achieve stable and reliable low-frequency capture under the premise of meeting the natural frequency theoretical formula, effectively improving the manufacturing process efficiency and reducing costs; at the same time, it is easier to achieve lower frequency and distortion for the entire detector during operation;

[0045] 2. By constructing a new balance formula for the detector vibration system, a new balance is formed between the gravity of the inertial body and the resistance arm (the difference between the inner and outer diameters of the magnetic shoe end face) while keeping the size of the small core and the elastic force of the spring resistance arm unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of the structure of an embodiment of the present invention;

[0047] Figure 2 It is the mechanical model diagram of the magnetic shoe and the elastic element;

[0048] Figure 3 is the relationship between frequency and resistance arm Figure 1 ;

[0049] Figure 4 The relationship between distortion and resistance arm Figure 1 ;

[0050] Figure 5 is the relationship between frequency and resistance arm Figure 2 ;

[0051] Figure 6 The relationship between distortion and resistance arm Figure 2 ;

[0052] In the figure, the shell 101, the upper magnetic shoe 102, the upper top cover 103, the upper sealing ring 104, the upper contact gasket 105, the upper gasket 106, the insulating sheet 107, the upper outer contact spring 108, the upper inner contact spring 109, the first terminal 110, the second terminal 111, the circuit board 112, the first spring piece 113, the second spring piece 114, the third spring piece 115, the fourth spring piece 116, the upper retaining spring 117, the upper coil 118, the upper wire rack 119, the weight adjustment coil 120, the lower wire rack 121, the lower coil 122, the lower contact piece 123, the lower contact gasket 124, the lower gasket 125, the lower retaining spring 126, the lower top cover 127, the lower sealing ring 128, the lower magnetic shoe 129, the magnet 130, and the connecting sleeve 131. DETAILED DESCRIPTION

[0053] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0054] like Figure 1 As shown, in an embodiment of the present invention, a low-frequency detector with high precision and high stability is proposed, including a shell and a magnetic system installed in the shell; wherein the magnetic system includes an upper magnetic shoe 102, a magnet 130 and a lower magnetic shoe 129 installed in the shell from top to bottom; a closed magnetic field is formed by the magnetic system and the shell; an inertial body is installed in the shell and is placed outside the magnetic system, and the entire inertial body covers the magnetic system; and a detection circuit is also included for detecting the movement of the inertial body and cutting the induction signal generated by the closed magnetic field and outputting it; the closed magnetic field formed by the shell 101, the magnet 130, the upper magnetic shoe 102 and the lower magnetic shoe 129, during measurement, the inertial body moves relative to the shell to generate a magnetic flux cutting process, and the generated induction signal feeds back the wave detected at that time. In order to improve the current detector core diameter size, continue to explore the detection and response to lower frequencies, and optimize the size of the upper magnetic shoe 102 and / or the lower magnetic shoe 129 to meet the following formula:

[0055] Ld×F2=Lz×F1

[0056] In the formula,

[0057] Ld represents the power arm, which is the length of the elastic element sample in the inertial body;

[0058] Lz represents a resistance arm, which is the difference between the end surface outer diameter and the end surface inner diameter of the upper magnetic shoe 102 or the lower magnetic shoe 129;

[0059] F1 represents the elastic force of the resistance arm;

[0060] F2 represents the gravity of the inertial body;

[0061] The derivation process of the above formula is as follows:

[0062] It is known that the natural frequency formula of the elastic element as a frequency element is ;

[0063] in,

[0064] l, d—— length and cross-sectional dimensions (diameter or length and width) of the elastic element specimen,

[0065] k – constant,

[0066] E—— elastic modulus of material,

[0067] After deformation transformation, the formula is obtained ,

[0068] In this formula,

[0069] k is the stiffness of the elastic element, which has a direct relationship with the elastic modulus.

[0070] m —— the mass of the detector inertial body (mass block),

[0071] Based on the lever principle, the force of the elastic element and the magnetic shoe in the magnetic field is combined with Figure 2 The mechanical model shown can obtain the following parameters:

[0072] D1——Inner diameter of magnetic shoe end face;

[0073] D2——Outer diameter of magnetic shoe end face;

[0074] D3——outer diameter of spring leaf;

[0075] F1——Elastic force of the resistance arm, which affects the natural frequency stability, distortion and contact conductivity of the detector;

[0076] F2——Inertial body (coil frame, coil) power, this force determines the natural frequency;

[0077] F3——Lever fulcrum and fulcrum force, this force affects the capture, stability and distortion of the detector frequency;

[0078] F4——Inertial body (coil frame, coil) power, tangential rotation force generated by dynamic process (irresistible natural force);

[0079] F5——The resistance between rotating gap components relative to F4 is generated with F1 as the leading factor. This force affects the distortion index of the detector and the capture and stability of the natural frequency.

[0080] F6, F7 - radial force components generated by the inertial body (coil frame, coil) in the dynamic process;

[0081] According to the frequency formula and mechanical model, we can get:

[0082] mg=F2;

[0083] l=Ld, Ld is the power arm;

[0084] Ld=D3-D2;

[0085] Lz=D2-D1;

[0086] The formula is derived based on the lever balance principle

[0087] Ld×F2=Lz×F1

[0088] It can be seen from the formula that if Lz remains unchanged while F2 increases exponentially, F1 needs to be increased exponentially. However, F1 is mainly positively correlated with the length of the elastic element. When F1 increases with F2, F3-F7 will become disordered and difficult to coordinate, thus breaking the balance of the detector vibration system; and the elastic element will experience axial and radial movement during operation, which will increase the frequency and distortion of the detector and cause extremely poor stability.

[0089] According to the newly derived formula, it can be known that when F2 increases, F1 remains unchanged and the corresponding resistance arm Lz increases, that is, the outer diameter of the end face of the magnetic shoe is increased. Without changing the length of the elastic element, the entire system satisfies the natural frequency formula and can still be installed in a standardized core after changing the diameter of the magnetic shoe.

[0090] Through the derivation of the new formula, the detector can capture lower frequencies and guide the size changes of the magnetic shoe. Under the constraints of specific size conditions, more suitable parameters can be calculated.

[0091] Under the premise of adapting to the existing core diameter, the resistance arm Lz is preferably in the range of 9mm~13mm. When the Lz value range is 11mm~13mm, the vertical detector can obtain lower frequency and distortion, such as Figure 3 , Figure 4 As shown; when the value range of Lz is 9mm~13mm, the horizontal detector can stably obtain lower frequency and distortion, such as Figure 5 , Figure 6 shown.

[0092] like Figure 1As shown, the inertial body includes an upper wire rack 119, a connecting sleeve 131 and a lower wire rack 121 which are connected and installed in the housing from top to bottom in sequence; an upper coil 118 is wound on the upper wire rack 119; a lower coil 122 is wound on the lower wire rack 121, and the outlet end of the lower coil 122 is connected to the outlet end of the upper coil 118; at the same time, a weight adjustment coil 120 is wound at the connection position between the connecting sleeve 131 and the upper wire rack 119 and the lower wire rack 121; when relative movement occurs, the upper coil 118 and the lower coil 122 will cut the magnetic flux lines to generate signal feedback The current vibration frequency is fed back; the vibration is mainly fed back through the elastic element, and the first spring piece 113 and the second spring piece 114 are sequentially installed on the upper end of the upper wire rack 119, and are fixed by the upper retaining spring 117; the third spring piece 115 and the fourth spring piece 116 are sequentially installed on the lower end of the lower wire rack 121, and are fixed by the lower retaining spring 126; the whole inertial body moves during the detection, and the first spring piece 113 and the second spring piece 114 are in contact, or the third spring piece 115 and the fourth spring piece 116 are in contact, and the generated signal is transmitted through the detection circuit.

[0093] In order to prevent a passage from being formed between the upper magnetic shoe 102 and the first spring piece 113 , the second spring piece 114 , an insulating sheet 107 is provided between the first spring piece 113 , the second spring piece 114 and the upper magnetic shoe 102 .

[0094] During the detection process, the signal is mainly collected and transmitted through the detection circuit, and the signal is actually an electrical signal generated by cutting the magnetic flux lines; wherein the detection circuit includes a circuit board 112 mounted on the housing 101, and a first terminal 110 and a second terminal 111 fixed on the circuit board 112; the first terminal 110 is electrically connected to the magnetic system through the upper inner contact spring 109, and the magnetic system is electrically connected to the third spring sheet 115 and the fourth spring sheet 116; the first spring sheet 113 and the second spring sheet 114 are electrically connected to the upper coil 118;

[0095] The third spring piece 115 and the fourth spring piece 116 are electrically connected to the lower coil 122; the second terminal 111 is electrically connected to the first spring piece 113 and the second spring piece 114 via the upper outer contact spring piece 108; the electrical signal generated when the first spring piece 113 and the second spring piece 114 are in contact is transmitted through the second terminal 111, and the electrical signal generated when the third spring piece 115 and the fourth spring piece 116 are in contact is transmitted through the first terminal 110, and the currently captured vibration frequency can be obtained through subsequent signal processing.

[0096] In order to improve the contact accuracy between the first spring sheet 113 and the second spring sheet 114 and to form a gap between the first spring sheet 113 and the upper retaining spring 117 , an upper contact gasket 105 is provided between the first spring sheet 113 and the second spring sheet 114 ; an upper gasket 106 is provided between the first spring sheet 113 and the upper retaining spring 117 .

[0097] Similarly, a lower contact piece 123 is provided between the third spring piece 115 and the fourth spring piece 116, and a lower gasket 125 is provided between the fourth spring piece 116 and the lower retaining spring 126, which also ensures that the contact accuracy between the third spring piece 115 and the fourth spring piece 116 can be improved when moving downward, and a lower contact piece 123 is provided below the lower contact gasket 124.

[0098] When installing the magnetic system and the inertial body, they are mainly packaged through a shell, and the shell includes an outer shell 101, an upper top cover 103 installed at the upper end of the outer shell 101, and the upper top cover 103 is used to connect and fix the upper magnetic shoe 102; a lower top cover 127 installed at the lower end of the outer shell 101, and the lower top cover 127 is used to connect and fix the lower magnetic shoe 129; thereby the magnetic system and the inertial body are supported and installed to form a whole; wherein, an upper sealing ring 104 is provided between the upper top cover 103 and the outer shell 101, and a lower sealing ring 128 is provided between the lower top cover 127 and the outer shell 101, which play an internal sealing role.

[0099] The derived formula provides a basis for optimizing the design of the outer diameter of the magnetic shoe end face, and while satisfying the requirement that the core diameter of the prior art remains unchanged, it is possible to obtain detection results that capture lower frequencies and distortions.

[0100] In the explanation of the present invention, it should be noted that the terms "first", "second", "third", "fourth", etc. are only for the convenience of description and understanding, and do not limit the number of uses, installation order or importance of specific technical features.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A low-frequency detector with high precision and high stability, characterized in that: include: case; The magnetic system comprises an upper magnetic shoe, a magnet and a lower magnetic shoe which are sequentially installed in the housing from top to bottom; The magnetic system and the shell form a closed magnetic field; an inertial body, which is installed in the housing and placed outside the magnetic system; A detection circuit, used for detecting the movement of the inertial body and cutting the induction signal generated by the closed magnetic field and outputting it; The size optimization of the upper magnetic shoe and / or the lower magnetic shoe satisfies the following formula: Ld×F2=Lz×F1 In the formula, Ld represents the power arm, which is the length of the elastic element sample in the inertial body; D2——Outer diameter of magnetic shoe end face; D3——outer diameter of spring leaf; Ld=D3-D2 Lz represents a resistance arm, which is the difference between the outer diameter and the inner diameter of the end face of the upper magnetic shoe or the lower magnetic shoe; F1 represents the elastic force of the resistance arm; F2 represents the gravity of the inertial body.

2. A low-frequency detector with high precision and high stability according to claim 1, characterized in that: The inertial body comprises an upper wire rack, a connecting sleeve and a lower wire rack which are sequentially connected and installed in the housing from top to bottom; An upper coil is wound on the upper wire rack; A lower coil is wound on the lower coil rack, and an outlet end of the lower coil is connected to an outlet end of the upper coil; A weight adjustment coil is wound around the connection position between the connecting sleeve and the upper wire rack and the lower wire rack; The upper end of the upper wire rack is provided with a first spring sheet and a second spring sheet in sequence, and is fixed by an upper retaining spring; The third spring sheet and the fourth spring sheet are sequentially installed at the lower end of the lower wire frame and are limited and fixed by a lower clamping spring.

3. A low-frequency detector with high precision and high stability according to claim 2, characterized in that: An insulating sheet is provided between the first spring sheet, the second spring sheet and the upper magnetic shoe.

4. A low-frequency detector with high precision and high stability according to claim 3, characterized in that: The detection circuit includes a circuit board mounted on the housing, and a first terminal and a second terminal fixed on the circuit board; The first terminal is electrically connected to the magnetic system via an upper inner contact spring sheet, and the magnetic system is electrically connected to the third spring sheet and the fourth spring sheet; The first spring sheet and the second spring sheet are electrically connected to the upper coil; The third spring sheet and the fourth spring sheet are electrically connected to the lower coil; The second terminal is electrically connected to the first spring piece and the second spring piece via an upper external contact spring piece.

5. A low-frequency detector with high precision and high stability according to claim 4, characterized in that: An upper contact gasket is provided between the first spring sheet and the second spring sheet.

6. A low-frequency detector with high precision and high stability according to claim 5, characterized in that: An upper gasket is provided between the first spring sheet and the upper clamping spring.

7. A low-frequency detector with high precision and high stability according to claim 4, characterized in that: A lower contact pad is provided between the third spring piece and the fourth spring piece.

8. A low-frequency detector with high precision and high stability according to claim 7, characterized in that: A lower gasket is provided between the fourth spring sheet and the lower clamping spring.

9. A low-frequency detector with high precision and high stability according to any one of claims 1 to 8, characterized in that: The housing comprises: shell; An upper cover, mounted on the upper end of the housing and used to connect and fix the upper magnetic shoe; A lower top cover is installed at the lower end of the shell and is used to connect and fix the lower magnetic shoe.

10. A low-frequency detector with high precision and high stability according to claim 9, characterized in that: The value range of Lz is 9mm~13mm.

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