Electrodynamic vibration table moving coil framework based on peek material

Abstract

The invention discloses an electrodynamic vibration table moving coil framework based on a peek material, and relates to the field of vibration control, the electrodynamic vibration table moving coil framework comprises a table top, an upper end frame, a plurality of rib plates, a support ring and an inner frame, a short circuit ring sleeves the outer side wall of the support ring, a driving coil is wound on the outer side of the inner frame, and the table top, the upper end frame, the plurality of rib plates, the support ring and the inner frame are made of the peek material; the integral moving coil framework is made of a peek material, and the slotting design of a supporting ring below a rib plate is omitted; a driving coil is wound in the inner frame; a traditional moving coil framework has electrical conductivity, induced current can be generated in the framework under the influence of a driving coil, relatively high thermal power can be generated due to motion current generated by up-down motion, and the framework does not generate corresponding thermal power, so that the temperature of a moving coil in operation can be greatly reduced; the framework adopts an integral structure and cancels a support ring slotting design, so that the integral first-order frequency of the moving coil is greatly improved, the transverse strength of the moving coil is improved, and the use environment of the electric vibration table is expanded.

Description

Technical Field

[0001] The invention relates to the field of vibration control, and in particular to a dynamic frame of an electric vibration table based on peek materials. Background Art

[0002] Vibration testing technology is widely used in aviation, aerospace, construction, automobile and other fields. Currently, the most common vibration testing equipment is electric vibration table and hydraulic vibration table, which can meet most of the current testing needs. Electric vibration table is not only used for reliability verification of various products, but also for product performance identification and environmental adaptability assessment.

[0003] The working principle of the electric vibration table is the principle of electromagnetic induction. When the rated voltage is applied to the upper excitation coil and the lower excitation coil, a certain amount of current will be generated. Given that a constant magnetic field is provided by the excitation coil and the central magnetic pole, the driving coil (moving coil) is supplied with alternating current. The moving coil is subjected to alternating electromagnetic force under the action of the constant magnetic field. By controlling the size and polarity of the alternating electromagnetic force, the required vibration waveform can be generated. At present, domestic electric vibration tables have made great progress in research and production. However, with the increase in the thrust of the vibration table, some defects of the existing vibration table are also exposed.

[0004] The maximum value of the magnetic induction intensity of the existing electric vibration table is generally taken as a constant value due to the influence of the relative magnetic permeability characteristics of the material. According to the theoretical formula, in this case, the thrust of the electric vibration table mainly depends on the effective length of the moving coil and the size of the current passed into the moving coil. Therefore, in order to increase the thrust, the effective length of the moving coil is greatly increased, and the overall volume of the vibration table is increased. Another way to increase the thrust is to increase the current in the moving coil, which causes the moving coil to generate a lot of heat during operation. The source of heat is partly conductor loss and partly eddy current loss generated in the moving coil frame. At present, water cooling is usually used for heat dissipation of large-thrust vibration tables, and the test on the cooling system is becoming increasingly greater. In addition, water-cooled electric vibration tables are prone to burning of the moving coil and excitation of the vibration table due to pipeline leakage.

[0005] At the same time, the dynamic coil frame and driving coil of the current electric vibration table are a combined structure of upper and lower parts, connected together in the middle by epoxy resin and other materials, which greatly reduces the stiffness and first-order frequency of the dynamic coil, making the high-frequency characteristics of the electric vibration table poor, especially the first-order frequency of the large-thrust vibration table usually does not exceed 1500Hz. For high-frequency tests, it is easy to have uncontrolled responses due to the poor characteristics of the table body itself. For a large-thrust vibration table, if the mass of the dynamic coil frame is reduced, the effective thrust of the vibration table can be increased. And according to the design principle of the electric vibration table, its first-order frequency can be increased. Summary of the invention

[0006] The purpose of the present invention is to design a dynamic coil frame of an electric vibration table based on peek material in order to solve the above problems.

[0007] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0008] The dynamic coil skeleton of an electric vibration table based on peek material comprises a table top, an upper end frame, a plurality of rib plates, a support ring and an inner frame, a short-circuit ring is mounted on the outer wall of the support ring, a driving coil is wound around the outer side of the inner frame, reserved screw holes are arranged on the table top, the table top is fixed to the upper end face of the upper end frame, the upper ends of the plurality of rib plates are fixedly connected to the lower end face of the upper end frame, the lower ends of the plurality of rib plates extend into the inner side of the support ring, the rib plates are fixedly connected to the inner side of the support ring, the height of the lower end of the rib plates is lower than the height of the upper end of the inner frame, the second end of the support ring is fixedly connected to the inner frame, and the table top, the upper end frame, the plurality of rib plates, the support ring and the inner frame are made of polyetheretherketone peek material.

[0009] The beneficial effects of the present invention are: the peek material is made into an integral dynamic coil skeleton, including a dynamic coil table, an upper end frame, a rib plate, a driving coil inner frame, etc. At the same time, the slot design of the support ring below the rib plate is cancelled. The driving coil is wound in the inner frame; the traditional dynamic coil skeleton is conductive, and an induced current will be generated in the skeleton under the influence of the driving coil. At the same time, a dynamic current will be generated due to the up and down movement, thereby generating a large thermal power. The new skeleton will not generate corresponding thermal power, so the temperature of the dynamic coil during operation can be greatly reduced. In addition, the new dynamic coil adopts an integral configuration and cancels the slot design of the support ring, which greatly improves the overall first-order frequency of the dynamic coil, while improving the lateral strength of the dynamic coil and expanding the use environment of the electric vibration table. The above improvements can effectively improve the comprehensive performance of the electric vibration table. It has the characteristics of high operating reliability and superior performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of a support ring in the prior art;

[0011] Figure 2 It is a schematic diagram of the dynamic coil frame of the electric vibration table based on the peek material of the present invention;

[0012] Figure 3 It is a schematic diagram of the support ring in the dynamic coil of the dynamic coil frame of the electric vibration table based on peek material of the present invention.

[0013] The corresponding figures are as follows:

[0014] 1-table top, 2-upper frame, 3-rib plate, 4-support ring, 5-inner frame, 6-short-circuit ring, 7-slotted design, 8-non-slotted design. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0018] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0019] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0020] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0022] The dynamic coil skeleton of an electric vibration table based on peek material comprises a table top, an upper end frame, a plurality of rib plates, a support ring and an inner frame, a short-circuit ring is mounted on the outer wall of the support ring, a driving coil is wound around the outer side of the inner frame, reserved screw holes are arranged on the table top, the table top is fixed to the upper end face of the upper end frame, the upper ends of the plurality of rib plates are fixedly connected to the lower end face of the upper end frame, the lower ends of the plurality of rib plates extend into the inner side of the support ring, the rib plates are fixedly connected to the inner side of the support ring, the height of the lower end of the rib plates is lower than the height of the upper end of the inner frame, the second end of the support ring is fixedly connected to the inner frame, and the table top, the upper end frame, the plurality of rib plates, the support ring and the inner frame are made of polyetheretherketone peek material.

[0023] The table top, the upper end frame, a plurality of rib plates, a support ring and an inner frame are integrally formed.

[0024] The plurality of rib plates are arranged in a circular array with the central axis of the support ring of the table as the center.

[0025] The number of rib plates is 10 or 8.

[0026] At present, the electric vibration table system is increasingly testing the cooling system as the thrust increases. The temperature of the dynamic coil is relatively high during actual operation. Under long-term operation, the cooling system cannot ensure that the dynamic coil works at a reliable operating temperature in real time, so it is very easy for the dynamic coil to burn out. The existing vibration table has different degrees of damage after being disassembled and inspected after working at full load for a period of time. In addition, the current dynamic coils connect the frame and the drive coil in an upper and lower combination. In order to reduce the induced eddy current, the skirt is also slotted. The slotting methods include half slotting and full slotting, such as Figure 1 As shown in the figure, the first-order frequency and lateral strength of the moving coil are reduced, and test deviations are likely to occur during high-frequency excitation.

[0027] Based on the above reasons, this method uses peek material as the frame of the electric vibration table. Peek material has good material properties such as high strength, good insulation performance, and corrosion resistance. It is also a non-conductive non-metallic material and can be used in the design of the dynamic frame. Its specific design structure is as follows Figure 2 As shown in the figure, the components include the dynamic coil table, upper end frame, rib plate, support ring, inner frame, etc. The above parts adopt an integral configuration, and no longer separate the dynamic coil frame from the driving coil part in the connection combination. This improvement measure is a key factor in improving the first-order frequency of the dynamic coil. The interface connected to the airbag is reserved at the bottom of the dynamic coil frame to ensure the reliable transmission of the system's exciting force. Since there is no need to consider the influence of the eddy current effect, the slot at the skirt below the rib plate is eliminated, such as Figure 3 As shown. The axial first-order frequency and lateral strength of the dynamic coil are further improved, so that the dynamic coil can maintain good strength in a lateral centrifugal environment.

[0028] In actual use, this dynamic coil frame can be cooled by air or water. If air cooling is used, the winding complexity of the dynamic coil drive coil can be greatly simplified, the operating reliability of the dynamic coil can be improved, and the dynamic coil can be prevented from burning due to water cooling pipe leakage or mechanical damage. The dynamic coil of the electric vibration table using this design method can be installed in a vertical arm form in a centrifugal environment. At present, in the vibration and centrifugal composite environment test system, if the excitation equipment is an electric vibration table, it is installed and used in a straight arm form. When the dynamic coil is designed in an integrated manner, the electric vibration table can be installed in a vertical arm form because the lateral strength is greatly improved.

[0029] The table is consistent with the conventional dynamic coil frame table, and the reserved screw holes can be directly or indirectly connected to the test piece according to the needs. The upper end frame forms a whole with the table and plays a supporting role. The rib plate adopts a symmetrical configuration of 10 pieces (or 8 pieces), which can increase the first-order axial frequency of the dynamic coil. At the same time, the support ring under the rib plate cancels the original slot design, and the ring is a whole. This change can increase the first-order axial frequency and lateral strength of the dynamic coil. The length of the support ring under the rib plate is extended to the bottom of the traditional dynamic coil drive coil to form an integral dynamic coil configuration, and the drive coil is wrapped around the outside of the inner frame and packaged. The short-circuit ring is connected to the outside of the support ring on the lower side of the rib plate.

[0030] The dynamic coil adopts an integral structure instead of the traditional upper and lower connection structure to increase its first-order frequency and meet the high-frequency response.

[0031] Since there is no need to consider the influence of eddy current effect, the slot design of the support ring under the rib plate is eliminated, which further improves the first-order frequency and lateral strength of the dynamic coil.

[0032] The dynamic coil frame is made of non-metallic materials, which greatly reduces eddy current loss and heat generation. Therefore, air cooling is used to dissipate heat from the dynamic coil instead of the original complex water cooling system.

[0033] The power and heat generated by the dynamic coil frame of the original dynamic coil form are calculated through analytical formulas. The dynamic coil frame based on peek material is a non-metallic material and will not generate this part of power. The dynamic coil, short-circuit ring, and frame are mutually coupled due to the electromagnetic induction effect. Since the current flowing into the dynamic coil is large, it can be regarded as the primary winding of the transformer. The current in the short-circuit ring and the frame is relatively small, and can be regarded as the two secondary windings of the transformer. According to the equivalent circuit model, the following equation can be obtained:

[0034] ;

[0035] By solving the problem, we can get the induced current in the short-circuit ring and the frame. and :

[0036] ;

[0037] The short-circuit ring is designed as an outer single short-circuit ring. Its self-inductance and resistance value can be calculated according to the analytical formula. The self-inductance of the skeleton can be taken as 0.1~0.2 times of the self-inductance of the short-circuit ring according to the size. Since the short-circuit ring and the moving coil are closely connected, the leakage flux is very small, and the coupling coefficient can be close to 1. The gap between the skeleton and the driving coil is large, resulting in large leakage flux. Therefore, the coupling coefficient between the skeleton and the short-circuit ring is <0.5. The coupling between the short-circuit ring and the skeleton can be taken by multiplying the product of the above coupling coefficients by a coefficient, which is generally about 0.2.

[0038] The induced current density of the skeleton is derived as:

[0039] ;

[0040] In actual work, in addition to the induced current, the dynamic coil frame will also generate motional current due to the cutting of magnetic lines of force by up and down movement. The motional current density is calculated as follows:

[0041] ;

[0042] The derivation results show that the motional current density is only related to the speed of the skeleton movement and the skeleton resistivity, and the magnetic induction intensity B at the location of the skeleton is a certain value according to the actual situation. Since the thermal power generated by the skeleton's induced current and motional current can be directly superimposed, the total heating power can be easily calculated according to the thermal power formula. When peek material is used as the dynamic coil skeleton, since the material is a non-metallic material, there is no need to consider the above thermal power, so the temperature of the dynamic coil during operation can be significantly reduced.

[0043] The first-order frequency can be calculated by treating the moving coil as a two-degree-of-freedom or three-degree-of-freedom model. In the two-degree-of-freedom model, the mass of the table is assumed to be m1 and the mass of the rib plate is assumed to be m. 01 The mass of the connecting part is m2, the masses of the moving coil and the remaining part are m3 and m 02 . And define it as follows:

[0044] ;

[0045] Assume that the axial tensile and compressive stiffness of the table top is K 01 , the axial bending stiffness is K 02 , the axial stiffness of the winding frame is K 03 , the axial stiffness of the moving coil is K 04 , the stiffness of the table top is defined as: , the dynamic stiffness is: ; ; The first-order frequency of the moving coil as a whole is:

[0046] ;

[0047] like , , , the two-degree-of-freedom model can be changed to a three-degree-of-freedom model. Under the three-degree-of-freedom model, the first and second order resonance frequencies of the system are:

[0048] ;

[0049] Where: ;

[0050] The corresponding first-order frequency can be calculated based on the material properties. In addition, the density of peek material is about half of that of aluminum alloy material. Under the same size, the effective thrust of the platform can be increased, and the increase depends on the mass of the platform itself.

[0051] Since the peek material used is non-metallic, it will not generate eddy current loss and motional current loss, which greatly reduces the heat accumulated in the dynamic coil during use. It can reduce the requirements of the dynamic coil on the cooling system and does not require a complex water cooling system, thereby improving the reliability of the system.

[0052] The first-order frequency of the electric vibration table based on the moving coil of the present invention is greatly improved, which can meet the needs of high-frequency tests and effectively avoid the unstable control of the excitation test system under high-frequency excitation. At the same time, the lateral strength of the moving coil is greatly improved, and the excitation system can be installed in the vertical arm direction under the centrifugal field. The heat generation of the moving coil can be reduced by air cooling, without the need for a complex water cooling pipeline system, which improves the reliability and comprehensive performance of the excitation system.

[0053] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. The dynamic frame of the electric vibration table based on peek material is characterized by: It includes a table top, an upper end frame, multiple rib plates, a support ring and an inner frame. The short-circuit ring is mounted on the outer wall of the support ring, the drive coil is wound around the outer side of the inner frame, reserved screw holes are provided on the table top, the table top is fixed to the upper end surface of the upper end frame, the upper ends of the multiple rib plates are fixedly connected to the lower end surface of the upper end frame, the lower ends of the multiple rib plates penetrate into the inner side of the support ring, the rib plates are fixedly connected to the inner side of the support ring, the height of the lower end of the rib plates is lower than the height of the upper end of the inner frame, the second end of the support ring is fixedly connected to the inner frame, and the table top, the upper end frame, the multiple rib plates, the support ring and the inner frame are made of polyetheretherketone peek material.

2. The dynamic frame of the electric vibration table based on peek material according to claim 1 is characterized in that: The table top, the upper end frame, a plurality of rib plates, a support ring and an inner frame are integrally formed.

3. The dynamic coil frame of the electric vibration table based on peek material according to claim 1 is characterized in that: The plurality of rib plates are arranged in a circular array with the central axis of the support ring of the table as the center.

4. The dynamic frame of the electric vibration table based on peek material according to claim 3 is characterized in that: The number of rib plates is 10 or 8.

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