A high frequency fatigue dynamic loading testing machine for railway fastener spring bars

Abstract

The present invention relates to a high-frequency fatigue dynamic loading test machine for railway fastener spring bars, comprising a frame (1), a motor (2), a transmission shaft mechanism (3), a loading connecting rod mechanism (4), a loading block (5), a spring bar clamping seat structure (6), a protective cover (7) and a frame table (8), characterized in that the transmission shaft mechanism (3) comprises a small pulley (21), a camshaft (31), a large pulley (33) and a cam (34) on the output shaft of the motor (2), wherein the small pulley (21) is connected to the large pulley (33) through a toothed belt, the large pulley (33) and the cam (34) are installed on the camshaft (31), the loading connecting rod mechanism (4) contacts the cam (34), and the other end is connected to the loading block (5), and the loading block (5) is connected to the spring bar sample (62) installed on the spring bar clamping seat structure (6). Compared with the prior art, the output loading frequency of the loading block of the present invention can reach 5000Hz, and it has the advantages of safety and convenient observation.

Description

Technical Field

[0001] The present invention relates to a fastener spring clip fatigue testing machine in the railway field, in particular to a high-frequency fatigue simulation testing machine for spring clips. Background Art

[0002] As a key component in the railway track structure, the fastener system, especially the spring bars connecting the rails and the tracks, plays an important role in the safe operation of trains.

[0003] At present, the existing testing machines for fatigue testing of fastener spring bars can only perform fatigue tests at low frequencies below 20Hz. With the increase in train speed, especially the opening and operation of a large number of lines such as high-speed railways, the low-frequency test method of spring bars can no longer fully meet the requirements for spring bar design and application. In particular, for spring bars used in high-speed railways, according to many literature reports, the fatigue damage frequency band of spring bars is 500Hz to 700Hz. How to simulate high-frequency tests in the laboratory is beyond the reach of existing low-frequency testing machines or conventional high-frequency vibration test benches. Therefore, for this reason, it is necessary to design and simulate a fatigue test system for spring bars to perform high-frequency movements (≥20Hz). Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a high-frequency fatigue dynamic loading testing machine for railway fastener spring bars that can perform high-frequency dynamic fatigue simulation loading according to the response frequency of the spring bars in actual applications.

[0005] The object of the present invention can be achieved by the following technical scheme: A high-frequency fatigue dynamic loading test machine for railway fastener spring bars, comprising a frame, a motor, a transmission shaft mechanism, a loading connecting rod mechanism, a loading block and a spring bar clamping seat structure, a protective cover and a frame table, characterized in that the transmission shaft mechanism comprises a small pulley, a camshaft, a large pulley and a cam on the motor output shaft, wherein the small pulley is connected to the large pulley through a toothed belt, the large pulley and the cam are installed on the camshaft, the loading connecting rod mechanism contacts the cam, and the other end is connected to the loading block, and the loading block is connected to the spring bar sample installed on the spring bar clamping seat structure;

[0006] When in use, the starting motor drives the small pulley on the output shaft to rotate, thereby driving the large pulley, camshaft and cam to rotate. The cam drives the loading connecting rod mechanism to rotate at a high frequency periodicity, and the high frequency excitation generated is used through the loading block to perform high frequency amplitude excitation and fatigue loading on the pre-installed spring bar specimen installed in the clamp seat spring bar clamp seat structure.

[0007] Furthermore, the cam is an eccentric cam with an eccentricity range of 0mm to 5mm. The cam eccentricity can be adjusted according to the loading frequency and loading amplitude requirements to achieve the first-level low-frequency f1 and amplitude d1 dynamic loading. The range of f1 is 0-50Hz, f1=motor output speed / transmission ratio i, where the transmission ratio i=driving wheel speed / driven wheel speed=(driven wheel diameter / driving wheel diameter) / (1-slip rate); where the driving wheel is a small pulley and the driven wheel is a large pulley.

[0008] Furthermore, the cam is in a prototype or elliptical shape, and n concave-convex polygonal structures with uniform wavelength and wave depth d2 are evenly distributed on its circumferential surface to realize the second-level high-frequency loading, the range of n is 0-200, the high-frequency loading frequency f2 is realized, the range of d2 is 0-1mm; the high-frequency loading frequency f2=n·f1, the range of high-frequency loading frequency f2 is 0-5000Hz,

[0009] The cam may include structures of different diameters and different polygonal orders. Assuming the diameter of the cam is φ, the distance from the buckling point of the spring bar specimen to the fixed end of the loading connecting rod is l1, and the distance from the buckling point of the spring bar specimen to the movable end of the loading connecting rod is l2, then: the amplitude of the spring bar d = d2·l1 / (l1+l2).

[0010] Furthermore, the camshaft is fixed on the frame table through rolling bearing seats at both ends;

[0011] Furthermore, a manual rocker handle is provided at one end of the camshaft to manually adjust the meshing problem between the motor output small pulley and the large pulley and the toothed belt.

[0012] Furthermore, the loading connecting rod mechanism includes a bearing seat, a bearing, a loading connecting rod and a rolling bearing, a rolling bearing is arranged at one end of the loading connecting rod, and the other end is fixed to the bearing seat through a bearing, wherein the rolling bearing is in direct contact with the cam, the bearing seat is fixed on the frame table, and the loading block is connected to the loading connecting rod.

[0013] Furthermore, the rolling bearing rolls periodically at a high frequency around the circumference of the cam, and the loading connecting rod will generate a high-frequency excitation amplitude and transmit the high-frequency amplitude to the loading block. The hardness of the rolling bearing and the cam during high-frequency rolling contact is matched, and the materials of both need to be tempered and quenched.

[0014] Furthermore, the loading block is subjected to high-frequency vibration given by the cam during the test, and is subjected to a preload force given by the spring bar sample, wherein the preload force ranges from 0 to 20 KN.

[0015] Furthermore, the spring clip clamping seat structure includes a clamping seat, studs, and nuts. The spring clip specimen is installed and fixed on the clamping seat according to normal use conditions, and the preload force is adjusted by the studs and nuts at both ends of the clamping seat.

[0016] Furthermore, the spring clip clamping seat structure can be used to install and fatigue test different spring clip sample structures of fasteners, and the spring clip sample structures include "ω" type, "e" type, FC type and spring rod or spring piece;

[0017] Furthermore, strain gauges and sensors will be installed on the loading block and the spring bar sample, and the amplitude and frequency of the spring bar will be recorded through a test recording system.

[0018] Furthermore, the motor is a variable frequency motor, which can respond to the loading frequency modulation according to the use requirements of the spring bar sample, and the frequency modulation range is 0Hz to 100Hz. After passing through the transmission shaft mechanism and the loading connecting rod mechanism, the loading block outputs different loading frequencies.

[0019] Furthermore, the protective cover covers the working platform. During the test, the protective cover is in a fastened protective state to ensure the safety of the test. The protective cover is provided with a transparent observation surface to observe the test situation at any time; the whole test machine adjusts the horizontal state of the whole test machine through the four supporting feet of the frame.

[0020] Compared with the prior art, the test machine of the present invention is designed with an eccentric cam of a special structure, and the surface of the cam is provided with a plurality of protrusions and grooves. When the motor drives the eccentric cam to rotate, the loading connecting rod in contact with the surface of the eccentric cam can generate a high-frequency excitation amplitude, and the loading connecting rod will excite the loading block of the pre-installed spring bar specimen on the clamping seat with a high-frequency amplitude excitation and fatigue loading, and the loading block output loading frequency can reach 5000Hz. At the same time, the protective cover is in a fastened protection state during the test, which ensures the safety of the test, and the protective cover can be provided with a transparent observation surface to observe the test situation at any time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the transmission structure of the present invention.

[0023] Figure 3 It is a schematic diagram of the camshaft transmission structure of the present invention.

[0024] Figure 4 It is a schematic diagram of the cam structure of the present invention.

[0025] Figure 5 It is a schematic diagram of the loading connecting rod structure of the present invention.

[0026] Figure 6 It is a schematic diagram of the amplitude calculation principle of the present invention.

[0027] Figure 7This is a schematic diagram of the structure of the spring clip clamping seat of Example 1.

[0028] Figure 8 This is a schematic diagram of the structure of the spring clip clamping seat of Example 2.

[0029] Fig. 9 This is a schematic diagram of the structure of the spring clip clamping seat of Example 3.

[0030] In the figure, the symbols are as follows: 1. frame; 2. motor; 3. transmission shaft mechanism; 4. loading connecting rod mechanism; 5. loading block; 6. spring clip clamping mechanism; 7. protective cover; 8. frame table; 9. supporting foot; 10. table panel; 11. manual rocker handle; 21. small pulley; 31. camshaft; 32. camshaft bearing; 33 large pulley; 34. cam; 35. rolling bearing seat; 41. bearing seat; 42. bearing; 43. loading connecting rod; 44. rolling bearing; 61. clamping seat; 62. spring clip specimen; 63. stud; 64. nut; 65. spring clip seat; 66. base. DETAILED DESCRIPTION

[0031] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] like Figures 1-2 As shown, a high-frequency fatigue dynamic loading testing machine for railway fastener spring bars comprises a frame (1), a motor (2), a transmission shaft mechanism (3), a loading connecting rod mechanism (4), a loading block (5), a spring bar clamping seat structure (6), a protective cover (7) and a frame table (8), wherein the transmission shaft mechanism (3) comprises a small pulley (21), a camshaft (31), a large pulley (33) and a cam (34) on the output shaft of the motor (2), wherein the small pulley (21) and the large pulley (33) are connected to each other. 3) connected by a toothed belt, the large pulley (33) and the cam (34) are mounted on the camshaft (31), the camshaft (31) is fixed on the frame table (8) through rolling bearing seats (35) at both ends, a camshaft bearing 32 is provided between the camshaft 31 and the rolling bearing seat (35), a manual rocker handle (11) is provided at one end of the camshaft (31), and the meshing problem between the output small pulley (21) of the motor (2) and the large pulley (33) and the toothed belt is manually adjusted, such as Figure 3-4 shown.

[0034] The loading connecting rod mechanism (4) includes a bearing seat (41), a bearing (42), a loading connecting rod (43) and a rolling bearing (44). A rolling bearing (44) is arranged at one end of the loading connecting rod (43), and the other end is fixed to the bearing seat (41) through the bearing (42), wherein the rolling bearing (44) is in direct contact with the cam (34). The bearing seat (41) is fixed on the frame table (8), and the loading block (5) is connected to the loading connecting rod (43). The rolling bearing (44) rolls periodically at a high frequency around the circumference of the cam (34). The loading connecting rod (43) will generate a high-frequency excitation amplitude and transmit the high-frequency amplitude to the loading block (5) to drive the loading block 5 to dynamically load the elastic bar sample 62. When designing the rolling bearing (44) and the cam (34), the hardness matching problem during high-frequency rolling contact is considered, and the materials of both need to be tempered and quenched. Figure 5 shown.

[0035] The spring clip clamping seat structure (6) comprises a clamping seat (61), a stud (63), and a nut (64). The spring clip specimen (62) is fixed on the clamping seat (61) according to normal use conditions, and the preload force is adjusted by the studs (63) and nuts (64) at both ends of the clamping seat (61). Figure 2 , 6 As shown. During the test, the loading block 5 not only bears the high-frequency vibration given by the cam 34, but also bears the preload force given by the spring bar sample 62, and the preload force range is 0-20kN; the loading force of the spring bar sample is adjusted by the studs 63 and nuts 64 at both ends of the spring bar clamping seat structure 6. The spring bar clamping seat structure (6) can be used for the installation and fatigue test of the "ω" type fastener spring bar sample structure.

[0036] The protective cover (7) covers the tabletop 10 of the working platform. During the test, the protective cover (7) is in a fastened protective state to ensure the safety of the test. The protective cover (7) is provided with a transparent observation surface to observe the test situation at any time. The whole test machine is adjusted to a horizontal state through the four supporting feet (9) of the frame (1). Figure 1 shown.

[0037] The working principle of the high-frequency testing machine is as follows: the starting motor 2 drives the small pulley 21 on the output shaft, the toothed belt is connected to the large pulley 33 on the camshaft 31, and the cam 34 on the camshaft 31 is synchronously driven according to the designed transmission ratio. The cam 34 drives the rolling bearing 44 at one end of the loading link mechanism 4 to rotate periodically at a high frequency. The loading link 43 will generate a high-frequency excitation amplitude. The loading link 43 will excite the loading block 5 to perform high-frequency amplitude excitation and fatigue loading on the pre-installed spring bar 62 on the clamping seat 6. During the test, the protective cover 7 is in a buckled protection state. The entire testing machine will adjust the horizontal state of the entire testing machine through the four supporting feet 9 of the frame 1.

[0038] Combination Figure 1 , Figure 2 The motor 2 is a variable frequency motor, which can respond to the loading frequency according to the use requirements of the spring bar sample 62, and the frequency modulation range is 0Hz to 100Hz. After passing through the transmission shaft mechanism 3 and the loading connecting rod mechanism 4, the loading block 5 outputs a loading frequency of up to 5000Hz; the motor output small pulley 21 in the transmission shaft mechanism 3 and the large pulley 33 on the camshaft 31 are connected by a toothed belt, and the transmission ratio i=driving wheel speed / driven wheel speed=(driven wheel diameter / driving wheel diameter) / (1-slip rate), wherein the driving wheel is the small pulley (21) and the driven wheel is the large pulley (33).

[0039] Combination Figure 3 , Figure 4 In order to achieve high-frequency excitation effect on the circumference, the cam structure of the cam 34 is eccentrically set during design, and the eccentricity range is 0mm~5mm. The eccentricity distance of the cam 34 can be adjusted according to the loading frequency and loading amplitude requirements to achieve the first-level low-frequency f1 and amplitude d1 dynamic loading. The range of f1 is 0-50Hz, f1=motor output speed / transmission ratio i, where transmission ratio i=driving wheel speed / driven wheel speed=(driven wheel diameter / driving wheel diameter) / (1-slip rate); the driving wheel is the small pulley 21, and the driven wheel is the large pulley 33.

[0040] There are n polygons evenly distributed on the circumferential surface of the cam 34, and the concave-convex polygonal structure with uniform wavelength and wave depth d2 realizes the second-level high-frequency loading, the range of n is 0-200, and the high-frequency loading frequency f2 is realized, and the range of d2 is 0-1mm; the high-frequency loading frequency f2=n·f1, and the range of the high-frequency loading frequency f2 is 0-5000Hz. The cam 34 can include structures with different diameters and different polygon orders. Assume that the diameter of the cam 34 is φ, the distance from the buckling point of the spring bar sample 62 to the fixed end of the loading connecting rod 43 is l1, and the distance from the buckling point of the spring bar sample 62 to the movable end of the loading connecting rod 43 is l2, then: the amplitude of the spring bar d=d2·l1 / (l1+l2).

[0041] A certain number of uniform wavelengths and wave depth concave-convex structures, the number of wavelengths and wave depths in one cycle can be calculated according to the formula: n = simulation frequency / (selected motor output speed / transmission ratio i), where the transmission ratio i is the same as the above i value, and the cam 34 structure can be designed as a prototype or an ellipse.

[0042] Embodiment 2:

[0043] The main structure of Example 2 is the same as that of Example 1, and the difference lies in the different spring clip clamping mechanism 6. The other structures and implementation methods are the same as those of Example 1. This example is intended to illustrate the difference between the two.

[0044] Combination Figure 8 In this embodiment, since the sample spring bar structure is changed to a FC fastener spring bar, the sample spring bar will be fixed on the base 66 through the spring bar seat 65, and the preload force of the spring bar will be adjusted by the studs 63 and nuts 64 at both ends; the loading block 5 is still connected to the connecting rod, and the loading block 5 directly applies high-frequency amplitude to the middle ring of the sample spring bar.

[0045] Embodiment 3:

[0046] The main structure of the embodiment 3 is the same as that of the embodiment 1, and the difference lies in the different spring clip clamping mechanism 6. The other structures and implementation methods are the same as those of the embodiment 1. This embodiment is intended to illustrate the difference between the two.

[0047] Combination Fig. 9 In this embodiment, since the sample spring bar structure is changed to an "e"-type fastener spring bar, the sample spring bar will be fixed on the base 66 through the spring bar seat 65', and the preload force of the spring bar will be adjusted by the studs 63 and nuts 64 at both ends; the loading block 5 is still connected to the connecting rod, and the loading block 5 directly applies high-frequency amplitude to the rear toe of the sample spring bar.

Claims

1. A high-frequency fatigue dynamic loading testing machine for railway fastener spring bars, comprising a frame (1), a motor (2), a transmission shaft mechanism (3), a loading connecting rod mechanism (4), a loading block (5), a spring bar clamping seat structure (6), a protective cover (7) and a frame table (8), characterized in that: The transmission shaft mechanism (3) comprises a small pulley (21), a camshaft (31), a large pulley (33) and a cam (34) on the output shaft of the motor (2), wherein the small pulley (21) is connected to the large pulley (33) via a toothed belt, the large pulley (33) and the cam (34) are mounted on the camshaft (31), the loading connecting rod mechanism (4) contacts the cam (34), and the other end is connected to a loading block (5), and the loading block (5) is connected to a spring bar sample (62) mounted on a spring bar clamping seat structure (6); When in use, the starting motor (2) drives the small pulley (21) on the output shaft to rotate, thereby driving the large pulley (33), the camshaft (31) and the cam (34) to rotate, and the cam (34) drives the loading connecting rod mechanism (4) to rotate at a high frequency period, and the generated high frequency excitation is used through the loading block (5) to perform high frequency amplitude excitation and fatigue loading on the pre-installed spring clip specimen (62) installed in the spring clip clamping seat structure (6); The cam (34) is an eccentric cam, and the eccentric distance d1 ranges from 0 mm to 5 mm. The eccentric distance of the cam (34) is adjusted according to the requirements of the loading frequency and the loading amplitude to realize the dynamic loading of the first-level low frequency f1 and the amplitude d1. The range of f1 is 0-50 Hz, and f1=motor output speed / transmission ratio i, wherein the transmission ratio i=driving wheel speed / driven wheel speed=(driven wheel diameter / driving wheel diameter) / (1-slip rate); wherein the driving wheel is a small pulley (21), and the driven wheel is a large pulley (33); The cam (34) is elliptical, and a concave-convex polygonal structure with a uniform wavelength and a wave depth d2 of polygonal order n is evenly distributed on its circumferential surface to realize the second-level high-frequency loading, the range of n is 0-200, the high-frequency loading frequency f2 is realized, and the range of d2 is 0-1 mm; the high-frequency loading frequency f2 = n•f1, and the range of the high-frequency loading frequency f2 is 0-5000 Hz, The cam (34) includes structures with different diameters and different polygonal orders. Assuming that the diameter of the cam (34) is φ, the distance from the buckling point of the spring bar specimen (62) to the fixed end of the loading connecting rod (43) is l 1. The distance from the buckling point of the spring bar specimen (62) to the movable end of the loading connecting rod (43) is l 2, then: the amplitude of the spring bar d = d2• l 1 / ( l 1+ l 2).

2. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 1, characterized in that: The camshaft (31) is fixed on the frame table (8) via rolling bearing seats (35) at both ends; A manual rocker handle (11) is provided at one end of the camshaft (31) for manually adjusting the meshing problem between the output small pulley (21) of the motor (2) and the large pulley (33) and the toothed belt.

3. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 1, characterized in that: The loading connecting rod mechanism (4) comprises a bearing seat (41), a bearing (42), a loading connecting rod (43) and a rolling bearing (44); a rolling bearing (44) is arranged at one end of the loading connecting rod (43), and the other end is fixed to the bearing seat (41) through the bearing (42); the rolling bearing (44) is in direct contact with the cam (34); the bearing seat (41) is fixed on the frame table (8); and the loading block (5) is connected to the loading connecting rod (43).

4. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 3, characterized in that: The rolling bearing (44) rolls periodically at a high frequency around the circumference of the cam (34), and the loading connecting rod (43) generates a high frequency excitation amplitude and transmits the high frequency amplitude to the loading block (5). The hardness of the rolling bearing (44) and the cam (34) is matched when they are in high frequency rolling contact, and the materials of both need to be tempered and quenched.

5. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 3, characterized in that: During the test, the loading block (5) is subjected to high-frequency vibration given by the cam (34) and simultaneously to a preload force given by the spring bar specimen (62), wherein the preload force ranges from 0 to 20 kN.

6. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 1, characterized in that: The spring clip clamping seat structure (6) comprises a clamping seat (61), a stud (63), and a nut (64); the spring clip specimen (62) is mounted and fixed on the clamping seat (61) according to normal use conditions, and the preload force is adjusted by means of the studs (63) and nuts (64) at both ends of the clamping seat (61).

7. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 1, characterized in that: The spring clip mounting seat structure (6) is used to carry out installation and fatigue testing of different spring clip sample structures of fasteners, and the spring clip sample structures include "ω" type, "e" type, FC type and spring rods or spring pieces.

8. The high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 1, characterized in that: Strain gauges and sensors are installed on the loading block (5) and the spring bar sample (62), and the amplitude and frequency of the spring bar are recorded through a test recording system.

9. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 1, characterized in that: The motor (2) is a variable frequency motor, which responds to the loading frequency modulation according to the use requirements of the spring bar sample (62), and the frequency modulation range is 0 Hz to 100 Hz. After passing through the transmission shaft mechanism (3) and the loading connecting rod mechanism (4), the loading block (5) outputs different loading frequencies.

10. A high frequency fatigue dynamic loading testing machine for railway fastener spring bars according to claim 1, characterized in that: The protective cover (7) covers the working platform. During the test, the protective cover (7) is in a fastened protective state to ensure the safety of the test. The protective cover (7) is provided with a transparent observation surface to observe the test situation at any time. The horizontal state of the entire test machine is adjusted by the four supporting feet (9) of the frame (1).

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