Cam type vibration test device

Abstract

The present invention discloses a cam type shock test device, including a foundation, a base on the foundation, a cam type shock device and a vibration table, the cam type shock device includes a mounting base, a reduction motor, a reduction motor bracket, a cam shaft system component and a roller shaft system component mounted on the cam shaft system component, the cam shaft system component includes a camshaft and a bearing end cover, a bearing seat, a bearing spacer, a snail cam and a deep groove ball bearing on the camshaft, the roller shaft system component includes a roller shaft and a T-block on the roller shaft, a support seat is arranged on the top of the T-block, a waveform generator and a work surface are arranged in sequence from bottom to top above the support seat, the extension table includes a support frame and an extension disk above the support frame, the bottom of the extension disk extends from the lower middle part of the support frame and is connected to the top of the work surface. The present invention can be widely used in shock test assessments of various large-size and heavy-weight specimens.

Description

Technical Field

[0001] The invention belongs to the technical field of testing, and in particular relates to a cam type vibration test device. Background Art

[0002] The vibration test is one of the main test methods for evaluating the reliability of ship electronic equipment. It is often used to evaluate the adaptability and integrity of ship electronic equipment in the repetitive low-intensity impact environment caused by waves during navigation. It is an important item in the environmental identification test of ship electronic equipment. Ship electronic equipment is the core hub of the ship power system and is directly related to the stable operation and reliable power supply of the ship power system. The vibration caused by the instantaneous impact of waves, strong winds or sudden external forces is an environmental condition that ship equipment often encounters during navigation operations. The vibration usually acts on the ship equipment in the form of inertial load. The main direction of the vibration acceleration is along the vertical direction of the ship deck. The vibration acceleration caused by the same environment is much larger than its vibration acceleration, and the vibration can cause permanent damage such as imbalance of equipment force, damage to structural parts, loosening and breaking of fasteners. Vibration is of great significance to the stability and reliability of ship navigation and is one of the actual environmental conditions for the use of ships. The application of ship electronic equipment in ships has become an important part of modern navigation technology. With the rapid development of science and technology, modern navigation has put forward more stringent requirements on the performance, size and operation efficiency of ships. Electronic equipment on ships is the key to improving navigation safety and efficiency. With the growth of demand, the size and weight of ship electronic equipment are also increasing accordingly to adapt to the more complex and changeable navigation environment. This puts higher requirements on the expansion and adjustment capabilities of the vibration test system for large-sized and large-mass test pieces. At the same time, the vibration test system must be monitorable and can collect and monitor real-time data. For the vibration test of large-sized and large-mass test pieces, the traditional method of using impact tables or vibration tables, which is not efficient and cost-effective, is no longer feasible. In response to the above problems, it is necessary to design a vibration test device with large load-bearing capacity, conforming to the vibration test characteristics of periodic reciprocating motion, meeting certain economic benefits requirements, and capable of stable and reliable operation, so as to realize the vibration test assessment of large-sized and large-mass test pieces, which provides a theoretical reference basis for the vibration resistance design and reliability of ship electronic equipment, and is of great significance.

[0003] When conducting vibration tests on large-sized and heavy specimens, the following requirements are imposed on the vibration test device: (1) It can achieve periodic reciprocating motion under a load of 15T; (2) It can be connected to an expansion table to achieve scalability and flexibility to meet the vibration test assessment of large-sized specimens; (3) It can input test conditions into the supporting PLC control cabinet to realize automatic control of the cam-type vibration test device and meet the adjustability target of different test conditions; (3) The sensor feedback signal is processed by the data acquisition instrument and output to the upper computer of the vibration measurement system for display and recording to achieve real-time collection and monitoring of vibration test data; (4) The half-sine impact pulse required by the vibration test is generated by the waveform generator. By adjusting the material, thickness, number and drop height of the waveform generator, different pulse duration and peak acceleration requirements can be met. By adjusting the reduction motor parameter settings and then adjusting the rotational angular velocity of the snail cam, different pulse repetition frequencies can be obtained; (5) It can run smoothly, perform efficient and reliable work, and is easy to maintain in the later stage, with low loss and low cost.

[0004] The existing vibration test generally involves mounting the test piece on a working surface of an impact table or a vibration table through a fixed fixture for vibration testing. However, there are several problems with the vibration test of large-sized and heavy specimens: (1) Since the impact table or vibration table has a limited load-bearing capacity, the vibration test of large-mass specimens requires the selection of a specific large-tonnage impact table or vibration table for assessment in combination with the test conditions, which is not universal; (2) Since the impact table or vibration table has an expansion table of fixed size, the vibration test of large-sized specimens not only requires the additional design and processing of the table expansion adapter plate, but also requires the consideration of the additional load on the impact table or vibration table caused by the weight of the table expansion adapter plate, which may cause the work surface to become unstable and overturn, posing a potential safety risk; (3) During the test, it is very easy to cause irreversible damage to the dynamic coil, upper guide and other devices or mechanical components of the impact table or vibration table, resulting in equipment performance degradation or failure, and high subsequent maintenance and repair costs; (4) The vibration test of large-sized and heavy specimens is carried out using a traditional impact table or vibration table, which is more time-consuming and labor-intensive to implement in terms of test time and test cost. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a cam type vibration test device.

[0006] The present invention provides the following technical solutions:

[0007] A cam type vibration test device, including a foundation, a base on the foundation, a cam type vibration device and an expansion platform, the cam type vibration device including a mounting base, a reduction motor, a reduction motor bracket, a cam shaft system component and a roller shaft system component mounted above the cam shaft system component, the reduction motor including a reducer and a servo motor, the cam shaft system component including a camshaft and a bearing end cover, a bearing seat, a bearing spacer, a snail cam and a deep groove ball bearing on the camshaft, the camshaft is connected to the rotating shaft of the reduction motor through a chain coupling, the lower end of the bearing seat is connected to an adapter plate, the adapter plate is connected to the The mounting base is connected, the roller shaft system components include a roller shaft and a T-shaped block on the roller shaft, the roller shaft is installed in cooperation with the slot on the snail cam, a support seat is arranged on the top of the T-shaped block, four feet are arranged on the bottom of the support seat, a waveform generator and a work table are arranged above the support seat from bottom to top, the extension table includes a support frame and an extension disk above the support frame, a guide support and an airbag assembly are arranged between the support frame and the extension disk, the support frame is connected to the base, the bottom of the extension disk extends from below the middle of the support frame and is connected to the top of the work table.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] 1. The present invention has a strong load-bearing capacity. According to the large load capacity of the cam-type shock device and the working characteristics of the mechanical transmission, it can realize periodic reciprocating motion under a load of 15T.

[0010] 2. The present invention has scalability and flexibility. By keeping the working table interface of the cam-type vibration test device consistent with the bottom interface of the electric and hydraulic vibration table extension tables, it can be connected to the currently used conventional extension tables to expand the table size to 2500mm×2500mm. At the same time, the extension table can be flexibly designed and processed to meet the expansion needs of larger sizes.

[0011] 3. The present invention can generate the semi-sine shock pulse required by the shock test through the waveform generator. By adjusting the material, thickness and quantity of the waveform generator and the drop height, different pulse durations and peak accelerations can be obtained. By adjusting the reduction motor parameter settings and then adjusting the rotational angular velocity of the snail cam, different pulse repetition frequencies can be obtained.

[0012] 4. The present invention has certain economy, can run smoothly, perform efficient and reliable work, has good bearing capacity and stability, is easy to maintain in the later stage, has low loss and low price, and greatly reduces the equipment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This invention is a schematic diagram Figure 1 ;

[0014] Figure 2 This invention is a schematic diagram Figure 2 ;

[0015] Figure 3 It is a schematic diagram of a cam type shock device;

[0016] Figure 4 is a schematic diagram of the mounting base;

[0017] Figure 5 is a schematic diagram of the adapter board;

[0018] Figure 6 It is a schematic diagram of the camshaft;

[0019] Figure 7 is a schematic diagram of a snail cam;

[0020] Figure 8 is a schematic diagram of a waveform generator;

[0021] Fig. 9 It is a schematic diagram of a T-block;

[0022] Fig.10 is a schematic diagram of the support seat;

[0023] Fig.11 It is a schematic diagram of the combined structure of the support base and the mounting block;

[0024] Fig.12 This is a diagram of the limit block. Figure 1 ;

[0025] Fig.13 This is a diagram of the limit block. Figure 2 ;

[0026] Fig.14 It is a schematic diagram of the combined structure of the support seat and the limit block;

[0027] Fig.15 It is a schematic diagram of the combined structure of the support seat, the limit block and the mounting block;

[0028] Fig.16 It is a schematic diagram of the camshaft system components;

[0029] Fig.17 It is a schematic diagram of the combined structure of the roller shaft system components, support seat, limit block and mounting block;

[0030] Fig.18 It is a schematic diagram of the combined structure of the adapter plate, cam shaft system components, roller shaft system components, support seat, limit block and mounting block;

[0031] Fig.19 It is a schematic diagram of the expansion station;

[0032] Fig. 20 is a schematic diagram of the support frame;

[0033] Fig.21 This is a schematic diagram of the expansion disk;

[0034] Fig. 22 is a schematic diagram of a guide support;

[0035] Fig.23 is a schematic diagram of an air bag assembly;

[0036] Fig.24 It is a schematic diagram of the column base;

[0037] Fig.25 It is a principle block diagram of the present invention;

[0038] Fig.26 This is a mechanical model diagram of a cam type shock test device;

[0039] Fig. 27 is a schematic diagram of a waveform generator;

[0040] Fig.28 It is the relationship diagram between the dynamic load coefficient of rubber and the hardness HS;

[0041] Fig.29 It is the relationship diagram between rubber shear modulus G and hardness HS;

[0042] Fig.30 is a schematic diagram of a parallel waveform generator;

[0043] Fig.31 It is a schematic diagram of a series waveform generator.

[0044] Among them, 1-foundation, 2-base, 3-mounting base, 311-first groove, 312-second groove, 4-reduction motor, 41-reducer, 42-servo motor, 5-reduction motor bracket, 6-camshaft, 7-bearing end cover, 8-bearing seat, 9-bearing spacer, 10-snail cam, 101-slot, 11-deep groove ball bearing, 12-chain coupling, 13-adapter plate, 14-roller shaft, 15-T-block, 16-support seat, 17-waveform generator generator, 18-working table, 19-support frame, 20-expansion plate, 21-guide support, 211-support block, 212-telescopic tube, 22-airbag assembly, 221-support block, 222-airbag, 23-limit block, 131-limit block I, 232-limit block II, 24-mounting block, 25-column base, 26-compressed air source, 27-PLC control cabinet, 28-power distribution cabinet, 29-acceleration sensor, 30-data acquisition instrument, 31-host computer. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0046] like Figure 1-Figure 31 As shown, a cam type vibration test device includes a foundation 1, a base 2 on the foundation 1, a cam type vibration device and an expansion platform, the cam type vibration device includes a mounting base 3, a reduction motor 4, a reduction motor bracket 5, a cam shaft system component and a roller shaft system component mounted above the cam shaft system component, the reduction motor 4 includes a reducer 41 and a servo motor 42, the cam shaft system component includes a camshaft 6 and a bearing end cover 7, a bearing seat 8, a bearing spacer 9, a snail cam 10 and a deep groove ball bearing 11 on the camshaft 6, the camshaft 6 is connected to the rotating shaft of the reduction motor 4 through a chain coupling 12, the lower end of the bearing seat 8 is connected to the adapter plate 13, and the adapter plate 13 is connected to the mounting base 3, The roller shaft system components include a roller shaft 14 and a T-shaped block 15 on the roller shaft 14, the roller shaft 14 is installed in cooperation with the slot 101 on the snail cam 10, a support seat 16 is arranged on the top of the T-shaped block 15, and four feet are arranged on the bottom of the support seat 16, a waveform generator 17 and a work table 18 are arranged above the support seat 16 from bottom to top, the expansion table includes a support frame 19 and an expansion disk 20 above the support frame 19, a guide support 21 and an airbag assembly 22 are arranged between the support frame 19 and the expansion disk 20, the support frame 19 is connected to the base 2, and the bottom of the expansion disk 20 extends from the bottom of the middle of the support frame 19 and is connected to the top of the work table 18.

[0047] The cam type vibration test device has four foot side walls at the bottom of the support seat 16 provided with limit blocks 23 , the bottom surface of the support seat 16 is provided with a mounting block 24 , and the top of the T-shaped block 15 is connected to the mounting block 24 .

[0048] The cam type vibration test device has a first groove 311 and a second groove 312 disposed on its mounting base 3 , and the adapter plate 13 is connected to the bottom of the first groove 311 .

[0049] The cam-type vibration test device has four second grooves 312 , and the four feet at the bottom of the support seat 16 are respectively arranged corresponding to each second groove 312 .

[0050] The cam-type vibration test device has a support frame 19 that is a square frame. The guide support member 21 includes a support block 211 and a telescopic tube 212 in the middle of the support block 211. The airbag assembly 22 includes a support 221 and an airbag 222 above the support 221. The top of the telescopic tube 212 and the top of the airbag 222 are fixedly connected to the bottom of the expansion plate 20. The bottom of the support block 211 and the bottom of the support 221 are correspondingly connected to the frame of the support frame 19.

[0051] In the cam type shock test device, acceleration sensors 29 are installed at the four corners of the expansion plate 20 , and the acceleration signals detected by each acceleration sensor 29 are collected by a data acquisition device 30 and transmitted to a host computer 31 .

[0052] There are 7 bearing seats 8, 12 bearing spacers 9, 6 snail cams 10, 7 deep groove ball bearings 11, and 7 T-beams 15.

[0053] The base 2 is a standard model specimen manufactured by mechanical processing and has a universal standard interface. The base 2 serves as the supporting structure of the extension table, which makes the working process of the extension table relatively smooth, providing stable and reliable protection for the test process. At the same time, it can effectively avoid long-term load and damage to the cam-type vibration test device, thereby ensuring the stability and bearing capacity of the entire test system.

[0054] The mounting base 3 is a supporting component of the cam-type vibration test device, and its main function is to ensure the bearing capacity, stability and rigidity of the structure and to transmit dynamic loads.

[0055] The reduction motor 4 is an integrated structure consisting of a reduction gear 41 and a servo motor 42. The specification of the reduction gear 41 is FKBR220-L2, and the specification of the servo motor 42 is V7E-M18D-7R515-D2, both of which are standardized products selected according to test conditions. As a power transmission mechanism, the reduction motor 4 can not only change the rotation speed of the output shaft by reducing the rotation speed of the servo motor, but also adjust the output shaft torque as needed.

[0056] The reduction motor bracket 5 mainly plays the role of fixing and bearing the reduction motor 4 .

[0057] The camshaft 6 transmits the power of the reduction motor 4 to the passive component, thereby driving the roller shaft 14 to realize the operation of the equipment.

[0058] The bearing end cover 7 is a device for sealing the bearing, and its main functions are sealing, positioning and supporting. It can not only effectively protect the bearing from pollution and damage from the external environment, but also ensure the correct position of the bearing during normal operation of the equipment, and can also reduce the wear and friction of the bearing to ensure the stable operation of the equipment.

[0059] The bearing seat 8 is a component used to support the bearing, and plays the role of fixing the bearing, bearing the load and ensuring the normal operation of the bearing.

[0060] The bearing spacer 9 is mainly used to separate the bearings during transmission, to protect and support the bearings, to avoid friction caused by direct contact, and thus to cause bearing wear, which can effectively enhance the stability of the bearings and improve work efficiency.

[0061] The snail cam 10 is a main component for realizing vertical lifting and dropping during the shock test. When the camshaft 6 drives the snail cam 10 to rotate, the roller shaft 14 engaged on the snail cam 10 follows and performs periodic clearance motion.

[0062] The deep groove ball bearing 11 is used to transmit the torque of the reduction motor 4 and convert the motor power into mechanical power. It has the characteristics of strong radial bearing capacity, small friction resistance and high operating efficiency. It can withstand large radial and axial loads, and because of its small friction coefficient and torque, it helps to reduce equipment energy consumption and improve operational smoothness and stability. In addition, it can effectively reduce the bearing support force, reduce friction loss and energy loss, and improve mechanical operating efficiency.

[0063] The main function of the chain coupling 12 is to connect the shaft of the reducer 4 and the camshaft 6, transmit motion and torque, and compensate for the installation error between the shafts.

[0064] The adapter plate 13 is used to connect the bearing seat 8 and the mounting base 3. The mounting base 3 is provided with a first groove 311 and a second groove 312. Specifically, the adapter plate 13 is connected to the bottom of the first groove 311 on the mounting base 3, that is, the adapter plate 13, the camshaft 6, the bearing end cover 7 on the camshaft 6, the bearing seat 8, the bearing spacer 9, the snail cam 10 and the deep groove ball bearing 11 are all in the first groove 311.

[0065] The T-shaped block 15 and the support seat 16 are load-bearing members driven by the roller shaft 14 , and the adapter block 24 on the support seat 16 is used to connect the T-shaped block 15 and the support seat 16 .

[0066] The stopper 23 includes a stopper I 231 and a stopper II 232 of different sizes, which are composed of self-lubricating copper plates. The main function is to position the support seat 16, and to restrict the load-bearing member to only move up and down linearly, thereby avoiding displacement and deviation during the test. Specifically, the stopper 23 is in close contact with the inner wall of the second groove 312 and moves up and down in the second groove 312 together with the four feet of the support seat 16.

[0067] The work surface 18 is the main bearing component of the cam type vibration test device and is used for fixing the test piece fixture and installing the expansion table.

[0068] The support frame 19 is used to support the tabletop and reduce the load on the moving coil.

[0069] The mounting interface at the bottom of the expansion tray 20 is connected to the work surface 18 by bolts and gaskets, and the support frame 19 of the expansion table falls on the base 2. The expansion table and the base 2 are not fixed to facilitate the follow-up movement of the expansion table. According to the position and size requirements of the support frame 19, a modular installation arrangement can be performed, which greatly improves the flexibility of the structure, has the characteristics of simple structure, efficient construction, reusability and safety assurance, and can effectively improve the test efficiency.

[0070] The guide support member 21 is used to solve the problem of excessive eccentric load moment of the table when the center of gravity of a large-sized and heavy test piece is offset, thereby meeting the requirements of eccentric load moment and uniformity of the test.

[0071] The airbag assembly 22 consists of a support 221 and an airbag 222. The model of the airbag 222 is JBF-115-1. The support 221 is used to support and fix the airbag 222. The airbag 222 is made of high-elastic rubber material, has good durability and shock absorption, can effectively absorb and disperse vibration energy, and protect the safety of the expansion platform and surrounding structures; the airbag 222 is inflated and pressurized by a compressed air source 26 to provide stable and flexible support for the expansion disk 20, thereby improving the stability and reliability of the cam-type vibration test device.

[0072] Four column seats 25 are placed at the four corners of the support frame 19 to prevent the airbag 222 in the airbag assembly 22 from being damaged by being squeezed by the expansion disk 20 for a long time. The expansion disk 20 is connected to the guide support 21 and the airbag assembly 22, and the airbag 222 in the airbag assembly 22 is inflated and pressurized by the compressed air source 26, and the four column seats 25 are removed.

[0073] The vibration control is completed by the vibration control system, which includes a PLC control cabinet 27 and a power distribution cabinet 28. The PLC control cabinet 27 and the power distribution cabinet 28 are connected by cables, and the PLC control cabinet 27 and the reduction motor 4 of the cam-type vibration test device are connected by control lines and power lines. The control line is mainly used to transmit the control signal of the PLC control cabinet 27 to the reduction motor 4 of the cam-type vibration test device, and the power line mainly transmits electric energy to drive the reduction motor 4 of the cam-type vibration test device. The main function of the power distribution cabinet 28 is to receive and distribute electric energy, and then distribute the electric energy from the main power supply to the cam-type vibration test device through the PLC control cabinet 27, so as to ensure that the electric energy can be safely and stably transmitted to the cam-type vibration test device.

[0074] The PLC control cabinet 27 is mainly used for automatic control, and its core is a programmable logic controller. It processes the input signal through a preset program, and then outputs the corresponding control signal to realize the automatic control of the cam type vibration test device. The test conditions can be set through the operation panel on the PLC control cabinet 27, and it can be automatically adjusted according to different test conditions. The operation has the advantages of integration, convenience and intelligence, which greatly improves work efficiency and equipment performance.

[0075] The vibration measurement is completed by the vibration measurement system, which includes an acceleration sensor 29, a data acquisition device 30 and a host computer 31. The acceleration sensor 29, the data acquisition device 30 and the host computer 31 are connected in sequence for real-time monitoring of visual data, which can effectively and timely discover and solve abnormal test conditions to achieve real-time collection and monitoring of vibration test data. The vibration acceleration signal is picked up by the acceleration sensor 29, and the acceleration signal is sent to the pre-charge amplifier by the sensor cable. The charge amplifier converts the signal into a voltage signal for amplification, and the signal is sampled by the data acquisition device 30 to realize the collection of the signal. The collected signal is displayed, analyzed and processed in real time by the host computer 31 of the vibration measurement system, and can also be saved for secondary processing.

[0076] The waveform generator 17 is a device for forming a semi-sine shock pulse waveform. It simulates a typical undamped single-degree-of-freedom spring mass system by combining the falling mass and the waveform generator. It is one of the important components of the shock test device and can effectively play the role of buffering, shock absorption, vibration isolation and protection, reduce the transmission and diffusion of shock, and protect the parts of the equipment from damage.

[0077] The waveform generator 17 is used as a buffer medium, usually made of elastic materials such as rubber or felt, to generate the half-sine impact pulse required by the shock test. The snail cam 10 is driven to rotate by the reduction motor 4, and its working curve surface gradually approaches and contacts the roller shaft 14, and then lifts the work table 18 to the highest position. When the snail cam 10 rotates to the highest position, the work table will fall freely on the waveform generator 17 above the mounting base 3 to generate an upward acceleration, thereby forming the first collision. This cycle repeats, and when the required total number of collisions is reached, the machine can be shut down. The impact stiffness K of the ideal half-sine wave can be calculated through the calculation formula of the drop impact principle and the pulse duration and load mass required by the test. The thickness and combination form of the waveform generator are confirmed according to the waveform generator design, and the final design of the waveform generator is completed to generate the specified half-sine waveform, and further verified through pre-test and monitoring data to confirm the feasibility of the test plan.

[0078] (1) Drop shock principle

[0079] The cam-type shock test device simulates a typical undamped single-degree-of-freedom spring-mass system by dropping the table (including the load) onto the waveform generator. Its motion mode is simplified as follows: Fig.26 shown.

[0080] Assuming that the waveform generator stiffness K is linear, the dynamic equation of the system is:

[0081]

[0082] From the initial conditions hour, , Solving the differential equation yields:

[0083]

[0084] in, is the natural frequency of the system, and the impact acceleration amplitude is obtained:

[0085]

[0086] Impact duration for:

[0087]

[0088] The maximum deformation A of the waveform generator is:

[0089]

[0090] Initial Speed for:

[0091]

[0092] in, is the maximum overload.

[0093] The required stiffness K of the waveform generator is:

[0094]

[0095] The ideal half-sine wave impact stiffness K can be obtained by using formula 7 and the pulse duration and load mass of the test conditions.

[0096] (2) Waveform transmitter design

[0097] Static elastic design of waveform generator: When designing rubber buffer pads, the stiffness and dynamic allowable stress of rubber must be considered. Generally, the half-sine waveform generator (buffer) is designed to be cylindrical, such as Fig. 27 As shown, its stiffness is calculated by the following formula:

[0098]

[0099] in:

[0100]

[0101] Where: S is the shape factor of the rubber; D is the free width of the rubber cushion; H is the free height of the rubber cushion;

[0102]

[0103] Where: i is the influence coefficient of the geometric shape and hardness of the rubber spring; m is the proportional coefficient; S is the shape factor of the rubber; HS is the Shore hardness of the rubber (30-95);

[0104]

[0105] Where: G is the shear modulus of rubber, such as Fig.28 As shown;

[0106]

[0107] Where: E a is the apparent elastic modulus of rubber;

[0108] Dynamic elastic design of waveform generator: Rubber is a viscoelastic body, its strain lags behind stress, and the value of shear modulus is different from the value of static apparent shear modulus. When subjected to impact load or dynamic load (generally ), should be calculated according to the dynamic shear modulus. When calculating, it should be determined by testing as close to the use conditions of the rubber spring as possible. If the requirements are not high, the rubber hardness HS can be used to Fig.29 The dynamic load coefficient is given. The dynamic shear modulus is calculated by the following formula:

[0109]

[0110] Where: Gd is the dynamic elastic trimming modulus of rubber; j is the dynamic load coefficient of rubber;

[0111] If a single waveform generator cannot meet the requirements, several waveform generators can be used in combination. Fig.30 As shown, the stiffness calculation formula is as follows:

[0112]

[0113] Where: K is the parallel rubber stiffness; l i k is the distance from the center of a single rubber to the parallel center; i is the single rubber stiffness;

[0114] Series combination reference Fig.31 As shown, the stiffness calculation formula is as follows:

[0115]

[0116] Where: K is the series rubber stiffness; k i is the single rubber stiffness;

[0117] Allowable stress design of waveform generator: When designing a rubber waveform generator, the allowable stress and allowable strain of the rubber material under dynamic loads must also be considered. The specific parameters are shown in Table 1.

[0118] Table 1 Allowable stress and allowable strain of rubber materials under dynamic loads

[0119] state Allowable stress / MPa Allowable strain (%) compression ±1 5

[0120] By adjusting the material, thickness, quantity and drop height of the waveform generator to meet different pulse duration and peak acceleration requirements, and then adjusting the parameter settings of the reduction motor and the rotation angular velocity of the snail cam, different pulse repetition frequencies can be obtained. It also has the working goals of stability, reliability, high efficiency, monitorability and economy, so as to realize the vibration test assessment of large-sized and heavy specimens in an open environment.

[0121] The specific steps of the test are as follows:

[0122] 1. The base 2 is stably and reliably connected to the foundation 1 through large-diameter screws, pads, and nuts.

[0123] 2. Embed the deep groove ball bearing 11 and the bearing seat 8 into the camshaft 6 in sequence by heating and fitting, and then embed the bearing spacer 9 and the snail cam 10 into the camshaft 6 in sequence. Perform shaft end configuration along the camshaft 6, and arrange them alternately in the order of deep groove ball bearing 11, bearing seat 8, bearing spacer 9, snail cam 10, and bearing spacer 9. Install the bearing end cover 7 at the end of the camshaft 6 to complete the structural assembly of the camshaft system components.

[0124] 3. Insert the roller shaft 14 into the seven T-shaped blocks 15 in sequence, and fix the T-shaped blocks 15 at both ends to the roller shaft 14 through bolts and gaskets to complete the structural assembly of the roller shaft system components.

[0125] 4. Install two sizes of limit blocks 23 on the sides of the four feet of the support seat 16 respectively, connect the threaded holes on the seven T-shaped blocks 15 with the threaded holes on the seven mounting blocks 24 on the bottom of the support seat 16 in sequence through bolts and gaskets, fix the adapter plate 13 to the mounting base 3 through bolts and gaskets, fix the seven bearing seats 8 of the cam shaft system components on the adapter plate 13 in sequence, and then place the roller shaft system components on the slot 101 of the snail cam 10, install the waveform generator 17 and the work table 18 in sequence from bottom to top above the support seat 16, connect the reducer 41 and the servo motor 42 to form a reduction motor 4, connect the camshaft 6 and the rotating shaft of the reduction motor 4 through the chain coupling 12 to form a transmission main shaft, connect the reduction motor bracket 5 to the mounting base 3 through bolts and gaskets, and complete the assembly of the cam type vibration device.

[0126] 5. Hoist the support frame 19 onto the foundation 1, and then install the guide support 21 and the airbag assembly 22 in sequence by bolts, washers and nuts. Place four column seats 25 at the four corners of the support frame 19 to prevent the airbag 222 in the airbag assembly 22 from being squeezed and damaged by the expansion plate 20 for a long time. Hoist the expansion plate 20 to the top of the support frame 19, align it with the holes reserved on the expansion plate 20 for connecting the guide support 21 and the airbag assembly 22, and finally slowly lower it to keep the center of the expansion plate 20 consistent with that of the support frame 19. Connect the guide support 21 and the airbag assembly 22 to the expansion plate 20 by bolts and washers respectively, and complete the assembly of the expansion platform.

[0127] 6. Insert bolts into the installation interface at the bottom of the expansion table, hoist the expansion table to the top of the working table 18 of the cam-type vibration test device, and connect the installation interface at the bottom of the expansion table with the working table 18 of the cam-type vibration test device through bolt positioning. The support frame 19 at the bottom of the expansion table falls on the base 2. The expansion table and the base 2 are not fixed to facilitate the follow-up movement of the expansion table.

[0128] 7. Reasonably place the PLC control cabinet 27 according to the test site, connect the PLC control cabinet 27 and the power distribution cabinet 28 through cables, and connect the PLC control cabinet 27 and the reduction motor 4 of the cam-type vibration test device through control lines and power lines.

[0129] 8. Use adhesive to bond four acceleration sensors 29 to the monitoring positions at the four corners of the expansion disk 20, connect the acceleration sensor 29 and the data acquisition instrument 30 through signal lines, and then connect the data acquisition instrument 30 to the host computer 31 through a network cable. After confirming that the installation is complete, check all connections to ensure that the power supply and signal lines are securely connected, start the system, and measure whether the acceleration sensor 29 is working properly and accurately monitoring the vibration data.

[0130] 9. Before the test begins, the airbag 222 in the airbag assembly 22 is inflated and pressure maintained through the compressed air source 26, and the four column seats 25 placed at the four corners of the support frame 19 are removed. By inputting the test conditions on the operation panel of the PLC control cabinet 27, the reduction motor 4 can be driven to lift and drop the expansion table to meet the requirements of the vibration test state, and the smoothness, continuity and stability of the process can be observed.

[0131] 10. The impact stiffness K of the ideal half-sine wave can be calculated by using the drop impact principle calculation formula (7) and the test requirements of pulse duration and load mass. The thickness and combination form of the waveform generator 17 are confirmed according to the waveform generator design, and the final design of the waveform generator 17 is completed. It is further verified through preliminary tests and monitoring data to confirm the feasibility of the test plan.

[0132] 11. After connecting the transfer fixture to the expansion table through bolts and gaskets, lift the test piece to the center of the expansion table, align it with the installation hole and slowly lower it, and finally complete the assembly connection of the test piece through bolts and gaskets.

[0133] 12. The vibration test conditions are realized through the vibration control system, and the real-time collection and monitoring of vibration test data are realized through the vibration measurement system.

[0134] In this way, the accuracy of vibration tests on large-sized and heavy specimens in open environments can be assessed.

[0135] In summary, the cam-type shock device in the present invention can realize periodic reciprocating motion under a load of 15T, and can truly simulate the shock test environment of large-sized and heavy-weight specimens. The expansion table can meet the requirements of test eccentric load torque and uniformity, and its bottom interface is consistent with the interface of the work surface of the cam-type shock test device, so as to achieve the scalability and flexibility requirements of the shock test of large-sized and heavy-weight specimens. The base can be installed and arranged in a modular manner according to the position and size requirements of the support frame, so as to improve the flexibility of the structure and meet the load-bearing and size requirements of various types of expansion tables. The shock measurement system collects the signals of the acceleration sensor through the data acquisition instrument, and displays, analyzes and processes them in real time through the upper computer of the shock measurement system to realize real-time collection and monitoring of the shock test data. At the same time, the layout of the acceleration sensor follows the principle of multi-point relative layout and comparison of monitoring data, so that the monitoring results are accurate, authentic and referenceable, which plays a guiding role in the analysis of the shock test. The waveform generator can generate the half-sine impact pulse required by the shock test. The impact stiffness K of the ideal half-sine wave is determined through test conditions. The stiffness K of the waveform generator is then verified through calculation to complete the final design of the waveform generator to generate the specified half-sine waveform, thereby achieving accuracy assessment of the shock test for large-size and heavy specimens in an open environment.

[0136] The present invention can be widely used in the assessment of vibration tests on various large-size and heavy-weight specimens, as well as the design and construction of vibration test systems.

[0137] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A cam type vibration test device, characterized in that: The invention comprises a foundation (1), a base (2) on the foundation (1), a cam-type vibration device and an expansion platform. The cam-type vibration device comprises a mounting base (3), a reduction motor (4), a reduction motor bracket (5), a cam shaft system component and a roller shaft system component mounted on the top of the cam shaft system component. The reduction motor (4) comprises a reducer (41) and a servo motor (42). The cam shaft system component comprises a camshaft (6) and a bearing end cover (7) on the camshaft (6), a bearing seat (8), a bearing spacer (9), a snail cam (10) and a deep groove ball bearing (11). The camshaft (6) is connected to the rotating shaft of the reduction motor (4) by a chain coupling (12). The lower end of the bearing seat (8) is connected to an adapter plate (13). The adapter plate (13) is connected to the mounting base (3). The roller shaft system component comprises a camshaft (6) and a bearing end cover (7) on the camshaft (6). The bearing seat (8) is connected to an adapter plate (13). The adapter plate (13) is connected to the mounting base (3). The invention relates to a roller shaft (14) and a T-shaped block (15) on the roller shaft (14), wherein the roller shaft (14) is mounted in cooperation with the slot (101) on the snail cam (10), a support seat (16) is arranged on the top of the T-shaped block (15), and four feet are arranged on the bottom of the support seat (16), and a waveform generator (17) and a work table (18) are arranged above the support seat (16) in order from bottom to top, and the expansion table comprises a support frame (19) and an expansion plate (20) above the support frame (19), and a guide support member (21) and an airbag assembly (22) are arranged between the support frame (19) and the expansion plate (20), and the support frame (19) is connected to the base (2), and the bottom of the expansion plate (20) extends from below the middle of the support frame (19) and is connected to the top of the work table (18).

2. The cam type shock test device according to claim 1, characterized in that: The four foot side walls at the bottom of the support seat (16) are provided with limit blocks (23), the bottom surface of the support seat (16) is provided with a mounting block (24), and the top of the T-shaped block (15) is connected to the mounting block (24).

3. The cam type vibration test device according to claim 1, characterized in that: The mounting base (3) is provided with a first groove (311) and a second groove (312), and the adapter plate (13) is connected to the bottom of the first groove (311).

4. The cam type vibration test device according to claim 3, characterized in that: There are four second grooves (312), and four feet at the bottom of the support seat (16) are respectively arranged corresponding to each second groove (312).

5. The cam type vibration test device according to claim 1, characterized in that: The support frame (19) is a square frame, the guide support member (21) comprises a support block (211) and a telescopic tube (212) in the middle of the support block (211), the airbag assembly (22) comprises a support (221) and an airbag (222) above the support (221), the top of the telescopic tube (212) and the top of the airbag (222) are both fixedly connected to the bottom of the expansion plate (20), and the bottom of the support block (211) and the bottom of the support (221) are both correspondingly connected to the frame of the support frame (19).

6. The cam type vibration test device according to claim 1, characterized in that: Acceleration sensors (29) are installed at the four corners of the expansion disk (20), and acceleration signals detected by each acceleration sensor (29) are collected by a data acquisition device (30) and transmitted to a host computer (31).

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