Bolt anti-fatigue test bench

Abstract

The utility model relates to the technical field of bolt tests, and discloses a bolt anti-fatigue test bench. Comprising a detection table, a cross beam located above the detection table, a guide column arranged on the detection table and penetrating through the cross beam, a lifting air cylinder arranged on the detection table and used for driving the cross beam to move, an upper clamp arranged on the lower side of the cross beam, a lower clamp arranged on the upper side of the detection table and a servo actuator arranged on the upper side of the cross beam. The two semicircular sleeves are located on the two sides of the upper clamp body and the two sides of the lower clamp body respectively and used for wrapping after splicing, connecting shells are arranged on the outer walls of the middles of the semicircular sleeves, electric heating wires distributed along the circumferential sides of the connecting shells are arranged in the connecting shells, and a plurality of strip-shaped holes communicated with the interiors of the connecting shells are formed in the inner walls of the semicircular sleeves; a controller used for controlling the temperature of the electric heating wire is arranged on the outer side of the connecting shell, a temperature detector used for detecting the temperature in the semicircular sleeve is arranged on the semicircular sleeve located on one side, and an opening and closing assembly used for adjusting the position of the semicircular sleeve is arranged between the guide column and the semicircular sleeve.

Description

Technical Field

[0001] This utility model belongs to the field of bolt testing technology, and specifically relates to a bolt fatigue resistance testing bench. Background Technology

[0002] The bolt fatigue test bench is a process testing instrument used in mechanical engineering and transportation engineering.

[0003] The core objective of bolt fatigue testing is to evaluate its performance degradation under dynamic loads. The following key indicators can be determined through testing:

[0004] Fatigue life: The number of cycles required for a bolt to go from its initial state to complete fracture, used to determine maintenance or replacement cycles.

[0005] Fatigue limit (durability limit): The limit of a bolt's lifespan at an infinite lifespan (e.g., 1×10⁻⁶). 7 The maximum stress amplitude that does not fail under multiple cycles provides a safety threshold for design.

[0006] Currently, Chinese patent CN212963929U, published on April 13, 2021, discloses a testing machine for axial fatigue and lateral vibration of fasteners. It includes a parallel frame base and a crossbeam, with a testing device mounted on the frame base. A crossbeam lifting mechanism is located between the crossbeam and the frame base, and a hydraulic servo drive mechanism is mounted on the crossbeam. The hydraulic servo drive mechanism is connected to the testing device via a detection device. The hydraulic servo drive mechanism includes a main cylinder, an accumulator, a valve plate, and a servo valve. The accumulator is connected to the main cylinder via the valve plate and the servo valve. The main cylinder is located at the bottom of the crossbeam, and its piston rod is connected to the testing device via the detection device. The detection device includes a load sensor assembly and a displacement measuring device. The load sensor assembly is connected between the main cylinder and the testing device and is used to measure the axial or lateral force on the sample. The displacement measuring device is mounted on the crossbeam and is used to measure the real-time displacement of the piston rod of the main cylinder during vibration.

[0007] This testing machine, which can perform axial fatigue and lateral vibration tests on fasteners, uses upper and lower clamps to hold and fix bolts, and then fatigue testing can be performed.

[0008] Meanwhile, Chinese patent publication number CN203132933U, published on August 14, 2013, discloses a large bolt low-temperature fatigue testing device, including a low-temperature environment chamber. The low-temperature environment chamber is composed of a hollow cylindrical irregular-shaped vertical Dewar, with a coaxial through hole at each of its upper and lower ends. The upper and lower pull rods are connected to a clamping system set inside the low-temperature environment chamber through the two through holes. The clamping system is used to clamp the test bolts. The upper and lower pull rods are connected to an external power source.

[0009] This large-scale bolt low-temperature fatigue testing device uses liquid nitrogen to provide a low-temperature environment for the bolts by passing liquid nitrogen into a low-temperature environment chamber, and can then test the bolt's fatigue resistance under low-temperature conditions.

[0010] Temperature is one of the important factors affecting bolt fatigue. The strength and toughness of bolts will change under different temperature environments, thus affecting the service life of bolts. However, the existing technology only provides bolt fatigue performance testing under low temperature environment, and cannot provide high temperature environment, which is not conducive to comprehensive testing of bolt fatigue performance under different temperature environments. Utility Model Content

[0011] The purpose of this invention is to provide a bolt fatigue testing bench that can provide different temperature environments for the bolts to be tested.

[0012] The above-mentioned technical objective of this utility model is achieved through the following technical solution: a bolt fatigue testing bench, including a testing bench, a crossbeam located above the testing bench, a guide post set on the testing bench and passing through the crossbeam, a lifting cylinder set on the testing bench and used to drive the crossbeam to move, an upper clamp set on the lower side of the crossbeam, a lower clamp set on the upper side of the testing bench, a servo actuator set on the upper side of the crossbeam, and two semi-circular sleeves respectively located on both sides of the upper clamp and the lower clamp for splicing and wrapping. A connecting shell is provided on the outer wall of the middle part of the semi-circular sleeve. An electric heating wire is provided inside the connecting shell and distributed along the periphery of the connecting shell. A plurality of strip holes communicating with the inside of the connecting shell are opened on the inner wall of the semi-circular sleeve. A controller for controlling the temperature of the electric heating wire is provided on the outside of the connecting shell. A temperature detector for detecting the temperature inside the semi-circular sleeve is provided on one side of the semi-circular sleeve. An opening and closing component for adjusting the position of the semi-circular sleeve is provided between the guide post and the semi-circular sleeve.

[0013] A further feature of this invention is that both the upper and lower ends of the semicircular sleeve are provided with sealing rings for respectively abutting against the outer walls of the upper and lower clamps.

[0014] A further feature of this invention is that the sealing rings are provided in multiple portions and are evenly spaced along the vertical direction.

[0015] The present invention is further configured as follows: the opening and closing assembly includes a guide shaft disposed on the outer wall of the upper and lower ends of the semicircular sleeve, a guide hole opened on the guide post for the guide shaft to pass through, a connecting arm disposed between the ends of the two guide shafts away from the semicircular sleeve, a through hole opened in the middle of the connecting arm, a rotating shaft passing through the through hole, a threaded end disposed at one end of the rotating shaft, a threaded hole opened on the guide post for threaded connection of the threaded end, a limiting ring disposed on the rotating shaft and located on both sides of the through hole, and a knob disposed at the end of the rotating shaft away from the threaded end.

[0016] A further feature of this invention is that the semicircular sleeve is also provided with a refrigerant pipe for supplying liquid nitrogen.

[0017] A further feature of this invention is that the refrigerant pipe includes two semicircular pipes located on the sides of the two semicircular sleeves respectively.

[0018] In summary, this utility model has the following beneficial effects:

[0019] 1. When it is necessary to test the fatigue resistance of bolts under different temperature environments, after the upper and lower clamps are connected to the bolts, the two semi-circular sleeves are spliced ​​together and wrapped around the upper and lower clamps using the opening and closing components. Then, the heating wire inside the connecting shell is energized by the controller, and the current input to the heating wire is adjusted by the controller to control the temperature generated by the heating wire. The heat generated by the heating wire can simulate a high-temperature environment for the bolts, and the temperature is monitored by a temperature detector. Finally, different temperature environments can be provided for the bolts to be tested.

[0020] 2. By using sealing rings at both the upper and lower ends of the semi-circular sleeve, the sealing rings can abut against the outer walls of the upper and lower clamps, thereby reducing the heat loss;

[0021] 3. Multiple sealing rings are set and evenly distributed in the vertical direction. When the length of the bolt to be tested changes, thus changing the distance between the upper and lower clamps, the multiple sealing rings can stably abut the upper clamp at different height positions.

[0022] 4. When two semicircular sleeves need to be spliced ​​and wrapped between the upper and lower clamps, the guide shaft is moved in the guide hole by pushing the connecting arm. Then the two semicircular sleeves can move towards each other. When the semicircular sleeves are about to be spliced, the threaded end can be threaded into the threaded hole, so that the two semicircular sleeves are spliced ​​and locked. When the two semicircular sleeves need to be separated, the threaded end in the threaded hole is unscrewed first. Then the two semicircular sleeves can be moved towards each other, and finally the opening and closing of the semicircular sleeve positions can be completed.

[0023] 5. When a low-temperature environment is required for the bolt, the refrigerant pipe is also installed on the semi-circular sleeve. After the two semi-circular sleeves are spliced ​​and wrapped between the upper and lower clamps, the refrigerant pipe can be connected to the liquid nitrogen pipe. Then, liquid nitrogen can be injected between the two semi-circular sleeves to simulate a low-temperature environment for the bolt. The temperature can be monitored by a temperature detector. Finally, different temperature environments can be provided for the bolt to be tested.

[0024] 6. The refrigerant pipe consists of two semicircular pipes located on the sides of the two semicircular sleeves. When the two semicircular sleeves are spliced ​​together, the two semicircular pipes can be spliced ​​together. Since the semicircular pipes are located on the sides of the semicircular sleeves, interference between the semicircular pipes and the heating wire can be avoided. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of this utility model;

[0027] Figure 2 This is a schematic diagram showing the connection relationship between the semicircular sleeve and the opening / closing component in this utility model;

[0028] Figure 3 This is a partial sectional view of the connection relationship between the guide post, the semi-circular sleeve and the opening and closing assembly in this utility model, wherein the heating wire is represented by a dashed line.

[0029] In the diagram, 1. Testing platform; 11. Guide column; 12. Lifting cylinder; 13. Lower clamp; 2. Crossbeam; 21. Upper clamp; 22. Servo actuator; 3. Semicircular sleeve; 31. Connecting shell; 32. Heating wire; 33. Strip hole; 34. Controller; 35. Temperature detector; 36. Sealing ring; 37. Refrigerant pipe; 371. Semicircular pipe; 4. Opening and closing assembly; 41. Guide shaft; 42. Guide hole; 43. Connecting arm; 44. Through hole; 45. Rotating shaft; 46. Threaded end; 47. Threaded hole; 48. Limiting ring; 49. Knob. Detailed Implementation

[0030] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0031] A bolt fatigue resistance testing bench, with reference to Figure 1This bolt fatigue testing bench includes a testing platform 1, a crossbeam 2, guide columns 11, a lifting cylinder 12, an upper clamp 21, a lower clamp 13, a servo actuator 22, and two semi-circular sleeves 3. The crossbeam 2 is located above the testing platform 1, while the guide columns 11 are fixed to both sides of the testing platform 1 by bolts and pass through the crossbeam 2. The lifting cylinder 12 is connected at its lower end to the testing platform 1 and at its upper end to the side of the crossbeam 2. The upper clamp 21 is connected to the lower side of the crossbeam 2, and the lower clamp 13 is connected to the upper side of the testing platform 1. The servo actuator 22 is connected to the upper side of the crossbeam 2 and to the upper clamp 21. The force provided by the servo actuator 22 simulates the bolt's operating environment. Since the connection structure between the servo actuator 22, the upper clamp 21, and the lower clamp 13 is existing technology, the specific structure will not be described here.

[0032] Reference Figure 1 , Figure 2 , Figure 3 The two semicircular sleeves 3 are located on both sides of the upper clamp 21 and the lower clamp 13, respectively, and are used for splicing and wrapping. The middle outer wall of the semicircular sleeve 3 is integrally provided with a connecting shell 31. In order to facilitate the observation of the bolts, both the semicircular sleeve 3 and the connecting shell 31 are made of transparent high-temperature resistant material. The connecting shell 31 is equipped with heating wires 32 distributed along the periphery of the connecting shell 31. At the same time, the inner wall of the semicircular sleeve 3 has multiple strip holes 33 that communicate with the inside of the connecting shell 31. The outer side of the connecting shell 31 is also equipped with a device for controlling the heating. The controller 34 for the temperature of wire 32 includes a temperature detector 35 for detecting the temperature inside the semicircular sleeve 3, which is located on one side; at the same time, a refrigerant pipe 37 for supplying liquid nitrogen is connected to the semicircular sleeve 3, and the refrigerant pipe 37 includes two semicircular pipes 371 located on the sides of the two semicircular sleeves 3 respectively; the upper and lower ends of the semicircular sleeve 3 are connected to sealing rings 36 for respectively abutting against the outer walls of the upper clamp 21 and the lower clamp 13, and multiple sealing rings 36 are provided and evenly spaced along the vertical direction.

[0033] Reference Figure 1 , Figure 2 , Figure 3An opening and closing assembly 4 for adjusting the position of the semicircular sleeve 3 is also provided between the guide post 11 and the semicircular sleeve 3. The opening and closing assembly 4 includes a guide shaft 41, a guide hole 42, a connecting arm 43, a through hole 44, a rotating shaft 45, a threaded end 46, a threaded hole 47, a limiting ring 48, and a knob 49. There are two guide shafts 41, which are respectively fixed to the outer walls of the upper and lower ends of the semicircular sleeve 3 by bolts. The guide shafts 41 extend horizontally. The guide hole 42 is opened on the guide post 11 and allows the guide shaft 41 to pass through. The connecting arm 43 is... Bolts are fixed between the ends of the two guide shafts 41 away from the semi-circular sleeve 3; a through hole 44 is opened in the middle of the connecting arm 43, and the rotating shaft 45 passes through the through hole 44. At the same time, the threaded end 46 is integrally set at one end of the rotating shaft 45, and the threaded hole 47 is opened on the guide post 11 for threaded connection of the threaded end 46. The limiting ring 48 is integrally set on the rotating shaft 45 and located on both sides of the through hole 44, and the outer diameter of the limiting ring 48 is larger than the inner diameter of the through hole 44. At the same time, the knob 49 is welded to the end of the rotating shaft 45 away from the threaded end 46.

[0034] Principle: When it is necessary to test the fatigue resistance of bolts under different temperature environments, after the upper clamp 21 and lower clamp 13 complete the connection of the bolt, the guide shaft 41 is moved in the guide hole 42 by pushing the connecting arm 43. Then, the two semi-circular sleeves 3 can move towards each other. When the two semi-circular sleeves 3 are about to be spliced, the threaded end 46 can be threaded into the threaded hole 47, so that the two semi-circular sleeves 3 are spliced ​​and locked. Then, the heating wire 32 in the connecting shell 31 is energized by the controller 34, and the current input to the heating wire 32 is adjusted by the controller 34 to control the temperature generated by the heating wire 32. The heat generated by the heating wire 32 can simulate a high temperature environment for the bolt, and the temperature is monitored by the temperature detector 35.

[0035] When a low-temperature environment is required for the bolt, the refrigerant pipe 37 is also provided on the semi-circular sleeve 3. After the two semi-circular sleeves 3 are spliced ​​and wrapped between the upper clamp 21 and the lower clamp 13, the refrigerant pipe 37 can be connected to the liquid nitrogen pipe. Then, liquid nitrogen can be injected between the two semi-circular sleeves 3 to simulate a low-temperature environment for the bolt. The temperature is monitored by the temperature detector 35. Finally, different temperature environments can be provided for the bolt to be tested.

Claims

1. A bolt fatigue testing bench, comprising a testing bench (1), a crossbeam (2) located above the testing bench (1), a guide column (11) disposed on the testing bench (1) and passing through the crossbeam (2), a lifting cylinder (12) disposed on the testing bench (1) and used to move the crossbeam (2), an upper clamp (21) disposed on the lower side of the crossbeam (2), a lower clamp (13) disposed on the upper side of the testing bench (1), and a servo actuator (22) disposed on the upper side of the crossbeam (2), characterized in that: It also includes two semi-circular sleeves (3) located on both sides of the upper clamp (21) and the lower clamp (13) respectively, which are used for wrapping after splicing. A connecting shell (31) is provided on the outer wall of the middle part of the semi-circular sleeve (3). A heating wire (32) is provided inside the connecting shell (31) and distributed along the periphery of the connecting shell (31). Multiple strip holes (33) communicating with the inside of the connecting shell (31) are provided on the inner wall of the semi-circular sleeve (3). A controller (34) for controlling the temperature of the heating wire (32) is provided on the outside of the connecting shell (31). A temperature detector (35) for detecting the temperature inside the semi-circular sleeve (3) is provided on one side of the semi-circular sleeve (3). An opening and closing component (4) for adjusting the position of the semi-circular sleeve (3) is provided between the guide post (11) and the semi-circular sleeve (3).

2. The bolt fatigue test bench according to claim 1, characterized in that: Both ends of the semicircular sleeve (3) are provided with sealing rings (36) for abutting against the outer walls of the upper clamp (21) and the lower clamp (13), respectively.

3. A bolt fatigue test rig according to claim 2, wherein: The sealing rings (36) are provided in multiple sizes and are evenly spaced along the vertical direction.

4. The bolt fatigue test bench according to claim 1, characterized in that: The opening and closing assembly (4) includes a guide shaft (41) disposed on the outer wall of the upper and lower ends of the semicircular sleeve (3), a guide hole (42) opened on the guide post (11) for the guide shaft (41) to pass through, a connecting arm (43) disposed between the ends of the two guide shafts (41) away from the semicircular sleeve (3), a through hole (44) opened in the middle of the connecting arm (43), a rotating shaft (45) passing through the through hole (44), a threaded end (46) disposed at one end of the rotating shaft (45), a threaded hole (47) opened on the guide post (11) for the threaded end (46) to be threadedly connected, a limiting ring (48) disposed on the rotating shaft (45) and located on both sides of the through hole (44), and a knob (49) disposed at the end of the rotating shaft (45) away from the threaded end (46).

5. The bolt fatigue test bench according to claim 1, characterized in that: The semi-circular sleeve (3) is also provided with a refrigerant pipe (37) for supplying liquid nitrogen.

6. A bolt fatigue test rig according to claim 5, wherein: The refrigerant pipe (37) includes two semicircular pipes (371) located on the sides of the two semicircular sleeves (3).

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