Low frequency long stroke pull-pull fatigue testing machine

Abstract

The application belongs to the technical field of fatigue testing machine, and discloses a low-frequency long-stroke tensile-tensile fatigue testing machine, which comprises a rack, a front rack and a rear rack, the front rack and the rear rack are fixedly connected, a moving cross beam is arranged on the rear rack and is limitingly connected with the rear rack through a penetrating pin mode, a pressure sensor is installed at the tail of the moving cross beam, a moving cross beam is arranged on the front rack, a test piece is connected between the moving cross beam and the moving cross beam, a guide rail is arranged on the front rack, and the moving cross beam moves along the guide rail, a hoisting system is arranged on the front rack, the hoisting system is connected with the moving cross beam through a steel wire rope, and is used for driving the moving cross beam to reciprocate. The hoisting system is adopted for driving, low-frequency reciprocating loading in a large stroke range can be realized, the structure is simple and reliable, the moving cross beam is accurately positioned through the penetrating pin locking mode, has high bearing capacity, and is suitable for long-stroke fatigue testing of large-size test pieces.

Description

Technical Field

[0001] This invention belongs to the field of fatigue testing machine technology, and particularly relates to a low-frequency long-stroke tensile fatigue testing machine. Background Technology

[0002] Currently, there are two main types of testing machines used for tensile fatigue testing of rigging or slender rods: electro-hydraulic servo fatigue testing machines and pulsating fatigue testing machines.

[0003] The pulsating fatigue testing machine generates periodic unidirectional pulsating hydraulic pressure through a pulsating cylinder, outputting a half-sine pulsating load. Its advantages include high load capacity, low cost, simple structure, and strong adaptability, capable of handling static loads, dynamic loads, and fatigue tests. However, its disadvantages are equally apparent: it can only achieve unidirectional pulsation, the waveform is fixed as a half-sine wave, and its waveform control capability is limited, making it difficult to meet complex loading requirements.

[0004] Electro-hydraulic servo fatigue testing machines can achieve various waveforms and have high control precision in applications with large loads, low frequencies, and long strokes. However, they have the following shortcomings: ① High cost, as large loads require large-diameter cylinders and high-flow-rate oil pumps; ② Long strokes result in huge hydraulic oil demand, leading to a high proportion of oil source costs; ③ High operating costs, requiring continuous cooling, regular replacement of hydraulic oil and seals, resulting in high energy consumption and complex maintenance.

[0005] Therefore, there is an urgent need for a low-frequency, long-stroke tensile fatigue testing machine to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a low-frequency long-stroke tensile fatigue testing machine to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: The present invention provides a low-frequency long-stroke tensile fatigue testing machine, comprising: The frame includes a front frame and a rear frame, which are fixedly connected. A movable crossbeam is mounted on the rear frame and is limitedly connected to the rear frame by a pin. A pressure sensor is installed at the tail of the movable crossbeam. A moving crossbeam is mounted on the front frame, and a test piece is connected between the moving crossbeam and the moving crossbeam. A guide rail is mounted on the front frame, and the moving crossbeam moves along the guide rail. A winch system is installed on the front frame. The winch system is connected to the moving crossbeam via a wire rope and is used to drive the moving crossbeam to reciprocate.

[0008] Preferably, the movable crossbeam includes a crossbeam body, through which a pressure sensor connecting rod passes. One end of the pressure sensor connecting rod is fixedly connected to a rear lifting lug, and a first rope loop fixture is installed on the rear lifting lug via a first tooling pin. The other end of the pressure sensor connecting rod is fixedly connected to a rear beam body. The pressure sensor is fixedly connected to the crossbeam body and located between the crossbeam body and the rear beam body. One end of the test piece is connected to the first rope loop fixture.

[0009] Preferably, multiple side ears are fixedly connected to both sides of the crossbeam body along the vertical direction, and the side ears are provided with crossbeam through holes. Multiple through holes are provided on the rear frame, and the crossbeam through holes are adapted to the through holes.

[0010] Preferably, the moving beam includes a moving beam body, one end of which is fitted with a second rope loop fixture via a second tooling pin, the other end of the test piece is connected to the second rope loop fixture, and the other end of the moving beam body is connected to the hoisting system.

[0011] Preferably, guide rails are provided on both sides of the moving beam body, and the guide rails are slidably connected to the guide rails.

[0012] Preferably, the hoisting system includes a bracket fixedly connected to the front frame, a power system and a first drum are provided on the bracket, the power system is used to drive the first drum to rotate, a plurality of fixed pulleys are installed on the bracket, a plurality of movable pulleys are installed on the moving beam body, and a wire rope is sleeved between the first drum, the fixed pulleys and the movable pulleys.

[0013] Preferably, the power system is a hydraulic motor or a servo motor.

[0014] Preferably, it also includes a return hoisting unit, which includes multiple fixed seats and multiple second drums. The fixed seats and the second drums are both fixedly connected to the front frame. A return pulley is installed on the fixed seat. One end of the return wire rope is fixedly connected to the moving beam body, and the other end of the return wire rope passes through the return pulley and is connected to the second drum.

[0015] Preferably, a first gear, a second gear, and a third gear are fixedly connected to the output end of the power system, the first drum, and the second drum, respectively, and the first gear and the third gear mesh with the second gear.

[0016] Preferably, the front frame and the rear frame are fixedly connected by bolts.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: This invention provides a low-frequency, long-stroke tensile fatigue testing machine. It employs a winch system with a wire rope to drive the moving crossbeam, enabling reciprocating motion over a large stroke range. This makes it particularly suitable for low-frequency, long-stroke fatigue testing conditions. The machine features a simple structure and low cost. The moving crossbeam is connected to the rear frame via a pin-type locking mechanism, allowing for rapid adjustment of its position according to the test piece length. The locking is reliable and effectively avoids the slippage problem of traditional clamping methods under heavy loads. A pressure sensor is located at the tail of the moving crossbeam, directly acquiring test loads and providing accurate and stable test data. The moving crossbeam is guided by guide rails, ensuring straightness and coaxiality during long-stroke motion, improving test repeatability and accuracy. The front and rear frames are fixedly connected to form an integral load-bearing frame, ensuring the rigidity and stability of the entire machine under repeated low-frequency, high-load impacts. This invention utilizes a winch system for driving, enabling low-frequency reciprocating loading over a large stroke range. The structure is simple and reliable. The pin-locking mechanism of the moving crossbeam provides accurate positioning and strong load-bearing capacity, making it suitable for long-stroke fatigue testing of large-size test pieces. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the frame structure of the present invention; Figure 3 This is a schematic diagram of the movable crossbeam structure of the present invention; Figure 4 This is a schematic diagram of the moving beam structure of the present invention; Figure 5 This is a schematic diagram of the hoisting system structure of the present invention; The components are as follows: 1. Frame; 11. Front frame; 12. Rear frame; 13. Through pin hole; 14. Guide rail; 2. Moving crossbeam; 21. Crossbeam body; 22. Pressure sensor connecting rod; 23. Rear lifting lug; 24. First tooling pin; 25. First rope loop tooling; 26. Rear beam body; 27. Pressure sensor; 28. Crossbeam through pin hole; 3. Moving crossbeam; 31. Moving crossbeam body; 32. Second tooling pin; 33. Second rope loop tooling; 34. Guide rail; 4. Hoisting system; 41. Support; 42. Power system; 43. First drum; 44. Fixed pulley; 45. Moving pulley; 46. Fixed seat; 47. Second drum; 48. Return pulley; 5. Test piece. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Reference Figures 1-5 This invention provides a low-frequency long-stroke tensile fatigue testing machine, comprising: The frame 1 includes a front frame 11 and a rear frame 12, which are fixedly connected. The movable crossbeam 2 is mounted on the rear frame 12 and is limited to the rear frame 12 by means of a pin. A pressure sensor 27 is installed at the tail of the movable crossbeam 2. The moving crossbeam 3 is set on the front frame 11. The test piece 5 is connected between the moving crossbeam 2 and the moving crossbeam 3. The guide rail 14 is set on the front frame 11, and the moving crossbeam 3 moves along the guide rail 14. The winch system 4 is installed on the front frame 11. The winch system 4 is connected to the moving crossbeam 3 via a wire rope and is used to drive the moving crossbeam 3 to reciprocate.

[0023] In one embodiment of the present invention, a winch system is used in conjunction with a wire rope to drive the moving crossbeam, enabling reciprocating motion over a large stroke range. This is particularly suitable for fatigue testing conditions involving low frequency and long strokes, and features a simple structure and low cost. The moving crossbeam is connected to the rear frame via a pin-type limiting connection, allowing for rapid adjustment of the crossbeam's position according to the test piece length. The locking is reliable, effectively avoiding the slippage problem of traditional clamping methods under heavy loads. A pressure sensor is located at the tail of the moving crossbeam, allowing for direct acquisition of test loads and accurate and stable test data. The moving crossbeam is guided by guide rails, ensuring straightness and coaxiality during long stroke motion, thus improving test repeatability and accuracy. The front and rear frames are fixedly connected to form an integral load-bearing frame, ensuring the rigidity and stability of the entire machine under repeated impacts from low-frequency, high-load conditions.

[0024] As an optional implementation, the movable crossbeam 2 includes a crossbeam body 21, through which a pressure sensor connecting rod 22 passes. One end of the pressure sensor connecting rod 22 is fixedly connected to a rear lifting lug 23. A first rope loop fixture 25 is installed on the rear lifting lug 23 via a first tooling pin 24. The other end of the pressure sensor connecting rod 22 is fixedly connected to a rear beam body 26. A pressure sensor 27 is fixedly connected to the crossbeam body 21 and located between the crossbeam body 21 and the rear beam body 26. One end of the test piece 5 is connected to the first rope loop fixture 25.

[0025] In one embodiment of the present invention, the first rope loop fixture 25 is installed by the first tooling pin 24, which facilitates the quick replacement of the corresponding rope loop fixture according to the test piece 5 of different specifications, thereby improving the versatility and replacement efficiency of the testing machine; the rear beam 26 serves as the force-applying end of the pressure sensor 27, which can uniformly apply the tension transmitted by the connecting rod to the force-bearing surface of the sensor, ensuring the uniformity of the force on the sensor and the linearity of the measurement.

[0026] As an optional implementation, multiple side ears are fixedly connected to both sides of the crossbeam body 21 along the vertical direction. The side ears are provided with crossbeam through holes 28, and multiple through holes 13 are provided on the rear frame 12. The crossbeam through holes 28 and through holes 13 are adapted to each other.

[0027] In one embodiment of the present invention, multiple side ears are provided with through holes, which cooperate with multiple through holes on the rear frame 12 to realize multi-level height adjustment of the moving crossbeam 2, which can adapt to the testing requirements of test pieces of different lengths.

[0028] As an optional implementation, the moving beam 3 includes a moving beam body 31. One end of the moving beam body 31 is fitted with a second rope loop fixture 33 via a second tooling pin 32. The other end of the test piece 5 is connected to the second rope loop fixture 33, and the other end of the moving beam body 31 is connected to the hoisting system 4.

[0029] In one embodiment of the present invention, a second rope loop fixture 33 is installed at one end of the moving crossbeam body 31 through a second fixture pin 32, which cooperates with the first rope loop fixture 25 to realize the quick clamping and replacement of both ends of the test piece 5; the pin-type installation structure makes the rope loop fixture easy to disassemble and assemble, and facilitates the quick replacement of fixtures of different sizes according to the test piece specifications, thereby improving the test efficiency.

[0030] As an optional implementation, guide rails 34 are provided on both sides of the moving beam body 31, and the guide rails 34 are slidably connected to the guide rails 14.

[0031] In one embodiment of the present invention, guide rails 34 are provided on both sides of the moving beam body 31, forming a double-sided guide with the guide rail 14 on the front frame, which ensures the linear running accuracy of the moving beam 3 in long-stroke reciprocating motion.

[0032] As an optional implementation, the hoisting system 4 includes a bracket 41, which is fixedly connected to the front frame 11. The bracket 41 is equipped with a power system 42 and a first drum 43. The power system 42 is used to drive the first drum 43 to rotate. Multiple fixed pulleys 44 are installed on the bracket 41, and multiple movable pulleys 45 are installed on the moving beam body 31. A wire rope is sleeved between the first drum 43, the fixed pulleys 44 and the movable pulleys 45.

[0033] In one embodiment of the present invention, a transmission method combining a drum and a pulley block is adopted. The pulley block is composed of multiple fixed pulleys 44 and movable pulleys 45, which can achieve large stroke output without increasing the size of the drum and meet the requirements of long stroke test.

[0034] As an alternative implementation, the power system 42 is a hydraulic motor or a servo motor.

[0035] In one embodiment of the present invention, the two power schemes can be flexibly selected according to actual test requirements and field conditions, thereby improving the applicability and configuration flexibility of the testing machine.

[0036] As an optional implementation, a return winch unit is also included. The return winch unit includes multiple fixed seats 46 and multiple second drums 47. Both the fixed seats 46 and the second drums 47 are fixedly connected to the front frame 11. A return pulley 48 is installed on the fixed seat 46. One end of the return wire rope is fixedly connected to the moving crossbeam body 31. The other end of the return wire rope passes through the return pulley 48 and is connected to the second drum 47.

[0037] In one embodiment of the present invention, an independent return hoisting unit is set up, which solves the problem that the wire rope can only transmit tension in one direction, and realizes the active bidirectional drive of the moving crossbeam 3, that is, both loading and return can be completed by power drive.

[0038] As an optional implementation, a first gear, a second gear, and a third gear are fixedly connected to the output end of the power system 42, the first drum 43, and the second drum 47, respectively, with the first gear and the third gear meshing with the second gear.

[0039] In one embodiment of the present invention, the first drum 43 and the second drum 47 can be driven to rotate synchronously by a single power system through gear meshing transmission.

[0040] As an optional implementation, the front frame 11 and the rear frame 12 are fixedly connected by bolts.

[0041] In one embodiment of the present invention, a bolted connection is used to form a reliable integral load-bearing structure between the front frame 11 and the rear frame 12, ensuring the structural rigidity and stability of the whole machine under heavy load reciprocating action.

[0042] In one embodiment of the present invention, before the test, the moving crossbeam 2 is first adjusted to a suitable height on the rear frame 12 and locked using a pin-operated method according to the length of the test piece 5. The two ends of the test piece 5 are connected between the moving crossbeam 2 and the moving crossbeam 3 via the first rope loop fixture 25 and the second rope loop fixture 33, respectively. The hoisting system 4 is started, and the power system 42 drives the first drum 43 to rotate, which in turn drives the moving crossbeam 3 to move along the guide rail 14 to the front end of the front frame 11 via the wire rope and pulley system, thereby applying a tensile load to the test piece 5. The pressure sensor 27 collects the load signal in real time and feeds it back to the control system. When the moving crossbeam 3 reaches the set end point of the stroke, the moving crossbeam 3 returns to its initial position by reversing the return hoisting unit or the first drum 43, completing one loading cycle. By setting the reversing frequency of the power system 42, low-frequency long-stroke reciprocating fatigue loading can be achieved.

[0043] Compared with traditional electro-hydraulic servo fatigue testing machines, the longer the stroke of this invention, the more obvious its advantages become. It is especially suitable for tensile fatigue testing machines or pulse fatigue testing machines with large loads, long strokes, and no need for pressure loads.

[0044] Compared to hydraulic servo testing machines, this application offers significant energy savings, with an energy conversion rate exceeding 90%. In pulsating fatigue testing, the rebound force of the specimen can be used to generate electricity for recovery, further saving energy and reducing operating costs. In terms of manufacturing, the hoisting system has lower material and processing costs compared to complex hydraulic devices, and its control is relatively simple. In terms of usage, it eliminates the enormous heat generated by high-pressure, high-speed flowing hydraulic oil, requiring no independent cooling system, and it also eliminates the need for high-purity hydraulic oil and sliding friction seals, resulting in low maintenance costs. It can achieve compression-tension fatigue, tension-tension fatigue, and pulsating fatigue testing under sinusoidal control, accommodating both long-stroke, low-frequency testing of fiber ropes and short-stroke, high-frequency use of metal rigging, with even lower energy loss, especially in pulsating fatigue testing.

[0045] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0046] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A low-frequency long-stroke tensile fatigue testing machine, characterized in that, include: The frame (1) includes a front frame (11) and a rear frame (12), the front frame (11) and the rear frame (12) being fixedly connected; A movable crossbeam (2) is mounted on the rear frame (12) and is limitedly connected to the rear frame (12) by means of a pin. A pressure sensor (27) is installed at the tail of the movable crossbeam (2). A moving crossbeam (3) is set on the front frame (11), and a test piece (5) is connected between the moving crossbeam (2) and the moving crossbeam (3). A guide rail (14) is set on the front frame (11), and the moving crossbeam (3) moves along the guide rail (14). A hoisting system (4) is installed on the front frame (11). The hoisting system (4) is connected to the moving beam (3) by a wire rope and is used to drive the moving beam (3) to reciprocate.

2. The low-frequency long-stroke tensile fatigue testing machine according to claim 1, characterized in that: The movable crossbeam (2) includes a crossbeam body (21), through which a pressure sensor connecting rod (22) passes. One end of the pressure sensor connecting rod (22) is fixedly connected to a rear lifting lug (23). A first rope loop fixture (25) is installed on the rear lifting lug (23) via a first tooling pin (24). The other end of the pressure sensor connecting rod (22) is fixedly connected to a rear beam body (26). The pressure sensor (27) is fixedly connected to the crossbeam body (21) and located between the crossbeam body (21) and the rear beam body (26). One end of the test piece (5) is connected to the first rope loop fixture (25).

3. The low-frequency long-stroke tensile fatigue testing machine according to claim 2, characterized in that: Both sides of the crossbeam body (21) are fixedly connected with multiple side ears along the vertical direction. The side ears are provided with crossbeam through holes (28), and the rear frame (12) is provided with multiple through holes (13). The crossbeam through holes (28) and the through holes (13) are adapted to each other.

4. The low-frequency long-stroke tensile fatigue testing machine according to claim 1, characterized in that: The moving beam (3) includes a moving beam body (31), one end of which is equipped with a second rope loop fixture (33) via a second tooling pin (32), the other end of which is connected to the second rope loop fixture (33), and the other end of which is connected to the hoisting system (4).

5. A low-frequency long-stroke tensile fatigue testing machine according to claim 4, characterized in that: Guide rails (34) are provided on both sides of the moving beam body (31), and the guide rails (34) are slidably connected to the guide rails (14).

6. A low-frequency long-stroke tensile fatigue testing machine according to claim 4, characterized in that: The hoisting system (4) includes a bracket (41) fixedly connected to the front frame (11). The bracket (41) is equipped with a power system (42) and a first drum (43). The power system (42) is used to drive the first drum (43) to rotate. The bracket (41) is equipped with multiple fixed pulleys (44). The moving beam body (31) is equipped with multiple movable pulleys (45). A wire rope is sleeved between the first drum (43), the fixed pulleys (44) and the movable pulleys (45).

7. A low-frequency long-stroke tensile fatigue testing machine according to claim 6, characterized in that: The power system (42) is a hydraulic motor or a servo motor.

8. A low-frequency long-stroke tensile fatigue testing machine according to claim 6, characterized in that: It also includes a return hoisting unit, which includes multiple fixed seats (46) and multiple second drums (47). The fixed seats (46) and the second drums (47) are both fixedly connected to the front frame (11). A return pulley (48) is installed on the fixed seat (46). One end of the return wire rope is fixedly connected to the moving beam body (31). The other end of the return wire rope passes through the return pulley (48) and is connected to the second drum (47).

9. A low-frequency long-stroke tensile fatigue testing machine according to claim 8, characterized in that: A first gear, a second gear, and a third gear are fixedly connected to the output end of the power system (42), the first drum (43), and the second drum (47), respectively. The first gear and the third gear mesh with the second gear.

10. A low-frequency long-stroke tensile fatigue testing machine according to claim 1, characterized in that: The front frame (11) and the rear frame (12) are fixedly connected by bolts.

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