Test sample, test clamp and test method for rotary riveting rocker arm assembly of gas compressor

Abstract

The invention provides a test sample, a test fixture and a test method for a rotary riveting rocker arm assembly of a gas compressor. The invention discloses a test sample for a rotary riveting rocker arm assembly of a gas compressor. The test sample is used for measuring shear stress of fracture at a rotary riveting joint of a rocker arm in the rotary riveting rocker arm assembly. The test sample comprises a rocker arm sample and a rocker arm pin sample. The rocker arm sample comprises a connecting part and a testing part. The connecting part is used for being connected with a test clamp. The test part is provided with a riveting hole, and the rocker pin sample is riveted in the riveting hole. The rocker arm sample is flat-plate-shaped. The material strength of the rocker arm sample is smaller than that of the rocker arm pin. The test sample can improve the measurement accuracy.

Description

Technical Field

[0001] This invention relates to the technical field of air compressors, and more particularly to a test specimen, test fixture, and test method for an air compressor riveted rocker arm assembly. Background Technology

[0002] The large passenger engine is a typical high-bypass turbofan engine, developed to meet the power requirements of my country's large civil aircraft. Compared to large transport engines, the large passenger engine has requirements for longer lifespan, higher reliability, and better economy. With the increasing bypass ratio and performance of commercial engines, the demands for reliability and economy are also increasing. The 0-3 stage rocker arms in the engine's VSV (Variable Stator Vane) mechanism are made of Ti-6Al-4V (domestic grade TC4) material. Due to the performance requirements of the compressor VSV adjustment mechanism, the rocker arms need to undergo torsional elastic deformation to adjust the rotation of the linkage ring. Compared to rigid stainless steel rocker arms, the TC4 material rocker arms, due to their elastic deformation under operating conditions, are called flexible rocker arms, and their advantage is that the linkage ring will not deform during use.

[0003] The TC4 flexible rocker arm is connected to the A286 material pin by riveting. During engine operation, the rotation of the flexible rocker arm adjustment linkage ring will cause shear stress in the riveting area between the rocker arm and the pin. Since A286 is harder than TC4, the flexible rocker arm (TC4) end will break prematurely.

[0004] However, the riveting structure of the aforementioned flexible rocker arm and pin is not widely used, and there are no reference standards or test standards for the rocker arm and pin riveting connection components in the industry. Furthermore, due to the complex structure of the actual flexible rocker arm, it is impossible to accurately measure its fracture shear stress and the fracture shear strength at the riveting connection of the flexible rocker arm. Consequently, it is impossible to obtain the safety factor, lifespan, fracture mode, and other characteristics of the flexible rocker arm in design and use, thus affecting the performance and reliability of the compressor. Summary of the Invention

[0005] The purpose of this invention is to provide a test specimen, test fixture, and test method for a compressor riveting rocker arm assembly, which can improve the accuracy of measurement.

[0006] One aspect of the present invention provides a test specimen for a compressor riveting rocker arm assembly, used to measure the shear stress at the riveting connection of the rocker arm in the riveting rocker arm assembly upon fracture; the test specimen includes a rocker arm specimen and a rocker arm pin specimen; wherein, the rocker arm specimen includes a connecting portion and a testing portion; the connecting portion is used to connect with a test fixture; the testing portion has a riveting hole, and the rocker arm pin specimen is riveted to the riveting hole; the rocker arm specimen is flat; the material strength of the rocker arm specimen is less than the material strength of the rocker arm pin specimen.

[0007] In one embodiment, the test portion of the rocker arm sample includes a test end and a connecting neck connecting the test end and the connecting portion; the outer peripheral edge of the test end is arc-shaped, and the rivet hole and the outer peripheral edge of the test end are concentrically arranged.

[0008] In one embodiment, the rocker arm pin sample includes an unriveted portion and a riveted portion; the riveted portion passes through the riveting hole of the rocker arm sample to be riveted to the riveting hole of the rocker arm sample.

[0009] In one embodiment, the connecting portion of the rocker arm specimen has a connecting hole for connecting with the test fixture; the center of the connecting hole and the center of the rivet hole are both located on the central axis of the rocker arm specimen.

[0010] In one embodiment, the material of the rocker arm specimen is AMS4911 TC4 titanium alloy; the material of the rocker arm pin specimen is AMS5731 A286 alloy.

[0011] Another aspect of the present invention provides a test fixture for a compressor riveted rocker arm assembly, used to test a test specimen of the compressor riveted rocker arm assembly as described in any of the above embodiments; the test fixture includes a first clamping structure for clamping the rocker arm specimen and a second clamping structure for clamping the rocker arm pin specimen connected to the rocker arm specimen; both the first clamping structure and the second clamping structure are connected to the testing machine, and the testing machine is used to apply a tensile load to the first clamping structure and the second clamping structure.

[0012] In one embodiment, the first clamping structure includes a first clamping member and a first limiting member; the first clamping member is provided with a first limiting hole through which the first limiting member passes, and the first limiting member can pass through the first limiting hole of the first clamping member and the rivet hole of the rocker arm sample, so as to fix the rocker arm sample to the first clamping member.

[0013] In one embodiment, the first clamping member is provided with a receiving groove for accommodating at least a portion of the connecting portion of the rocker arm sample; the connecting portion can be inserted into the receiving groove, the first limiting hole of the first clamping member passes through the receiving groove, and the first limiting hole and the rivet hole of the rocker arm sample are correspondingly provided, so that the first limiting member can pass through the rivet hole of the rocker arm sample located in the receiving groove.

[0014] In one embodiment, the second clamping structure includes a second clamping member and a second limiting member; the second clamping member is provided with a receiving portion for accommodating at least a portion of the rocker pin sample and a second limiting hole for the second limiting member to pass through; when the rocker pin sample is located in the receiving portion, the second limiting member and the second limiting hole cooperate to generate a clamping force acting on the rocker pin sample to press the rocker pin sample into the receiving portion.

[0015] In one embodiment, the second clamping member includes a base and a mating block; wherein the mating block is detachably disposed on the base; when the mating block is disposed on the base, the groove on the mating block and the groove on the base are opposite to each other to form the receiving portion; the base is provided with a receiving groove for receiving at least a portion of the rocker arm pin sample and the test end of the rocker arm sample, and the receiving groove and the receiving portion are connected.

[0016] In one embodiment, the second limiting member and the second limiting hole are threadedly connected; the second limiting member can abut against the riveted portion of the rocker arm pin sample, and during the threaded engagement of the second limiting member and the second limiting hole, the second limiting member generates a clamping force acting on the riveted portion.

[0017] Another aspect of the present invention provides a testing method for a compressor riveted rocker arm assembly, applied to a test fixture for a compressor riveted rocker arm assembly as described in any of the above embodiments; the testing method includes: riveting the rocker arm pin sample to the riveting hole of the rocker arm sample; assembling the rocker arm sample into a first clamping structure and assembling the rocker arm pin sample into a second clamping structure; fixing the first clamping structure and the second clamping structure to a testing machine; turning on the testing machine and applying a tensile load to the first clamping structure and the second clamping structure through the testing machine; and determining the shear strength of the rocker arm sample based on the fracture conditions of the rocker arm sample under different tensile loads.

[0018] The test specimen for the compressor riveted rocker arm assembly of this invention simulates a real flexible rocker arm using a rocker arm specimen and a rocker arm pin specimen simulating the rocker arm pin riveted to a real flexible rocker arm. The rocker arm specimen retains some structural features of a flexible rocker arm and is designed as a flat plate. This overcomes the problems of real flexible rocker arms being unable to be fixed to the testing machine due to stepped protrusions, and the complex stress conditions that prevent the measurement of pure shear stress after fixing, which makes it impossible to measure the pure shear stress. This invention allows for the measurement of pure shear stress using the test specimen, eliminating measurement errors caused by other irrelevant features of the real flexible rocker arm and improving measurement accuracy. Furthermore, this invention measures the shear stress at fracture of a real flexible rocker arm and characterizes its fracture mode, providing crucial support for the design and use of flexible rocker arms for adjustable stator blades of compressors, including safety factors, lifespan, and fracture modes. Attached Figure Description

[0019] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0020] Figure 1 This is a schematic diagram of a test specimen of a compressor riveting rocker arm assembly according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of a rocker arm pin sample before riveting, according to an embodiment of a test specimen of a compressor riveting rocker arm assembly based on the present invention.

[0022] Figure 3 yes Figure 2 The diagram shown is a schematic of the rocker pin sample after riveting.

[0023] Figure 4 yes Figure 2 The rocker arm pin sample shown is riveted to Figure 1 A schematic diagram of the rocker arm sample shown;

[0024] Figure 5 This is a schematic diagram of an embodiment of a test fixture for a compressor riveting rocker arm assembly according to the present invention;

[0025] Figure 6 yes Figure 5 A cross-sectional view of the test fixture shown;

[0026] Figure 7 yes Figure 5 A schematic diagram of the first clamping element of the test fixture shown;

[0027] Figure 8 yes Figure 5 A schematic diagram of the base of the test fixture shown;

[0028] Figure 9 yes Figure 5 A schematic diagram of the mating blocks of the test fixture shown;

[0029] Figure 10 This is a schematic flowchart of an embodiment of the test method for a compressor riveting rocker arm assembly according to the present invention;

[0030] Figure 11a This is a schematic diagram of a first example of the shear fracture surface of the rivet hole of a rocker arm specimen obtained by the test method according to the present invention;

[0031] Figure 11b This is a schematic diagram of a second example of the shear fracture surface of the rivet hole of a rocker arm specimen obtained by the test method according to the present invention;

[0032] Figure 11c This is a schematic diagram of a third example of the shear fracture surface of the rivet hole of a rocker arm specimen obtained by the test method according to the present invention;

[0033] Figure 11d This is a schematic diagram of a fourth example of the shear fracture surface of the rivet hole of a rocker arm specimen obtained by the test method according to the present invention;

[0034] Figure 12a It is a combination Figures 11a to 11d A schematic diagram of an example of a shear fracture surface;

[0035] Figure 12b yes Figure 12a A schematic diagram of the cross-section of the fracture surface;

[0036] Figure 13a This is the load-stroke curve of a rocker arm specimen with a nominal thickness of 1.02 mm under a riveting pressure of 1.3 MPa.

[0037] Figure 13b This is the load-stroke curve of the rocker arm specimen with a nominal thickness of 1.27 mm under a riveting pressure of 1.1 MPa in a shear test according to the present invention;

[0038] Figure 13c The load-stroke curve of the rocker arm specimen with a nominal thickness of 1.27 mm under a riveting pressure of 1.3 MPa is shown.

[0039] Figure 13d The load-stroke curve of the rocker arm specimen with a nominal thickness of 1.27 mm under a riveting pressure of 1.5 MPa is shown.

[0040] Figure 13e This is the load-stroke curve of a rocker arm specimen with a nominal thickness of 1.52 mm under a riveting pressure of 1.3 MPa. Detailed Implementation

[0041] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the invention and not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the invention without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0042] As used herein, the terms “first” and “second” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the individual components.

[0043] Figure 1 and Figure 2 An embodiment of a test specimen for a compressor riveted rocker arm assembly of the present invention is shown. The test specimen for the compressor riveted rocker arm assembly of the present invention is used to measure the shear stress at the riveted joint of the rocker arm in the riveted rocker arm assembly, that is, the shear strength at the riveted joint on the rocker arm used for riveting with the rocker arm pin. The test specimen includes a rocker arm specimen 100 and a rocker arm pin specimen 200. The rocker arm specimen 100 is designed for the flexible rocker arm in a riveted rocker arm assembly of a real compressor's VSV mechanism, and the rocker arm pin specimen 200 is designed for the rocker arm pin riveted to the flexible rocker arm in the riveted rocker arm assembly. The rocker arm specimen 100 and the rocker arm pin specimen 200 of the present invention are designed to simulate a real riveted rocker arm assembly.

[0044] like Figure 1 As shown, the rocker arm specimen 100 includes a connecting portion 110 and a testing portion 120. The connecting portion 110 is used to connect with a testing fixture. The testing fixture is a tooling used to hold the rocker arm specimen 100 and the rocker arm pin specimen 200, and is further connected to a testing machine for shear stress measurement. The testing portion 120 has a riveting hole 123, to which the rocker arm pin specimen 200 is riveted.

[0045] This invention measures the shear stress of a real flexible rocker arm fracture and characterizes its fracture mode, providing crucial support for the design and use of flexible rocker arms for compressor adjustable stator blades in terms of safety factor, lifespan, and fracture mode.

[0046] The rocker arm sample 100 is flat, which can overcome: 1) the real flexible rocker arm due to the corresponding Figure 1The connection portion 110 shown has a tapered step protrusion that prevents it from being fixed to the fixture; 2) After the real flexible rocker arm is fixed, it will tilt, and its central axis and the tensile load applied by the testing machine will not be on the same straight line. The complex stress situation will lead to the problem that it is impossible to measure its pure shear stress. The test specimen of the present invention can measure the pure shear stress, eliminate the measurement error caused by other irrelevant characteristics of the real flexibility, and improve the accuracy of the measurement.

[0047] In this embodiment, the material strength of the rocker arm specimen 100 is less than that of the rocker arm pin specimen 200, which can simulate the material strength between a real flexible rocker arm and a rocker arm pin. To match the parameter characteristics of the 0-3 level flexible rocker arm and rocker arm pin in a real VSV mechanism, the material of the rocker arm specimen 100 can be AMS4911TC4 (i.e., Ti-6Al-4V, domestic grade TC4) titanium alloy, and the material of the rocker arm pin specimen 200 can be AMS5731 A286 (domestic grade, strength 896MPa after solution treatment and aging, elongation 15%) alloy. Of course, other materials can also be used for the rocker arm specimen 100 and the rocker arm pin specimen 200; this invention does not impose any limitations.

[0048] In one embodiment, the test portion 120 of the rocker arm sample 100 includes a test end 121 and a connecting neck 122 connecting the test end 121 and the connecting portion 110. For example... Figure 1 As shown, from left to right, the components are the connecting portion 110, the connecting neck 122, and the test end 121. The connecting neck 122 and the connecting portion 110 retain some features that do not affect shear stress measurement, such as the connecting hole 111 for the test fixture connection. The test end 121 retains the characteristics of a real flexible rocker arm, namely the shape of the test end 121, the shape and diameter of the rivet hole 123, to maximize the reproduction of the riveted connection characteristics of a real flexible rocker arm. Specifically, the outer periphery of the test end 121 is arc-shaped, and the outer periphery of the rivet hole 123 and the test end 121 are concentrically arranged. This ensures that the cross-sectional area of ​​the shear fracture surface remains consistent, facilitating the calculation of the shear test structure. The centers of the connecting hole 111 and the rivet hole 123 are both located on the central axis of the rocker arm specimen 100.

[0049] The nominal thickness of the rocker arm sample 100 can be selected from three specifications: 1.02mm, 1.27mm, and 1.52mm. The specific thickness still needs to be measured from the processed sample; the dimensional accuracy is ±0.1mm, and the roughness is not greater than Ra 0.4μm. The diameter of the rivet hole 123 is 4.3mm (0 / +0.015), and the chamfer dimension of the rivet hole 123 is 0.45±0.05mm.

[0050] refer to Figure 2 and Figure 3 Rocker arm pin sample 200 includes located at Figure 2The upper unriveted portion 210 and the lower riveted portion 220. The riveted portion 220 passes through the riveting hole 123 of the rocker arm sample 100 and is riveted to it. Specifically, the height of the unriveted portion 210 is 4.9±1mm, and the diameter of the flash after upsetting is 7.2±0.8mm. Therefore, the height of the unriveted portion 210 of the riveted rocker arm will vary within the range of 3.9mm to 5.9mm. The rocker arm pin sample 200 of the present invention is consistent with the characteristics of a real rocker arm pin. Figure 4 The diagram illustrates the riveting state of a test specimen with rocker arm pin specimen 200 riveted to rocker arm specimen 100. The riveting pressure is determined based on the material strength of rocker arm specimen 100 and rocker arm pin specimen 200. In an embodiment where rocker arm specimen 100 is made of AMS4911 TC4 titanium alloy and rocker arm pin specimen 200 is made of AMS5731 A286 alloy (domestic grade), the riveting pressure can be selected as 1.1 MPa, 1.3 MPa, or 1.5 MPa.

[0051] like Figure 5 and Figure 6 As shown, the test fixture for the compressor riveting rocker arm assembly of the present invention is used to test the test specimen of the compressor riveting rocker arm assembly described above. The test fixture includes a first clamping structure 300 for clamping the rocker arm specimen 100 and a second clamping structure 400 for clamping the rocker arm pin specimen 200 connected to the rocker arm specimen 100. Both the first clamping structure 300 and the second clamping structure 400 are connected to a testing machine, which applies a tensile load to the first clamping structure 300 and the second clamping structure 400.

[0052] Both the first clamping structure 300 and the second clamping structure 400 are fixed by threaded connection between their ends and the testing machine.

[0053] Combination Figures 5 to 7 In one embodiment, the first clamping structure 300 includes a first clamping member 310 and a first limiting member 320. The first clamping member 310 is provided with a first limiting hole 311 through which the first limiting member 320 passes. The first limiting member 320 can pass through the first limiting hole 311 of the first clamping member 310 and the rivet hole 123 of the rocker arm sample 100, so that the rocker arm sample 100 is fixed to the first clamping member 310.

[0054] like Figure 7As shown, the first clamping member 310 is provided with a receiving groove 312 for accommodating at least a portion of the connecting portion 110 of the rocker arm sample 100. The thickness of the receiving groove 312 is adapted to the thickness of the rocker arm sample 100. The connecting portion 110 can be inserted into the receiving groove 312. The first limiting hole 311 of the first clamping member 310 passes through the receiving groove 312, and the first limiting hole 311 and the riveting hole 123 of the rocker arm sample 100 are correspondingly provided so that the first limiting member 320 can pass through the riveting hole 123 of the rocker arm sample 100 located in the receiving groove 312.

[0055] Specifically, the connecting part 110 of the rocker arm sample 100 is first inserted into the receiving groove 312, and then the first limiting member 320 is passed through the first limiting hole 311, the connecting hole 111 of the rocker arm sample 100, and the first limiting hole 311 on the other side, so as to fix the rocker arm sample 100 and the first clamping structure 300.

[0056] Combination Figure 5 , Figure 8 and Figure 9 The second clamping structure 400 includes a second clamping member 410 and a second limiting member 420. The second clamping member 410 is provided with a receiving portion 411 for accommodating at least a portion of the rocker arm pin sample 200 and a second limiting hole 412 through which the second limiting member 420 passes. When the rocker arm pin sample 200 is located in the receiving portion 411, the second limiting member 420 and the second limiting hole 412 cooperate to generate a clamping force acting on the rocker arm pin sample 200, thereby pressing the rocker arm pin sample 200 tightly within the receiving portion 411.

[0057] refer to Figure 8 and Figure 9 The second clamping member 410 includes a base 413 and a mating block 414. The mating block 414 is detachably mounted on the base 413. The mating block 414 and the base 413 can be connected by bolts. When the mating block 414 is mounted on the base 413, the groove 414a on the mating block 414 and the groove 413a on the base 413 face each other, forming a receiving portion 411. The base 413 is provided with a receiving groove 415 for receiving at least a portion of the rocker arm pin sample 200 and the test end 121 of the rocker arm sample 100; the receiving groove 415 and the receiving portion 411 are connected.

[0058] In one embodiment, the second limiting member 420 and the second limiting hole 412 are threadedly connected. The second limiting member 420 can abut against the riveted portion 220 of the rocker arm pin sample 200. During the threaded engagement of the second limiting member 420 and the second limiting hole 412, the second limiting member 420 generates a clamping force acting on the riveted portion 220. The degree of fixation between the rocker arm pin sample 200 and the base 413 can be adjusted by the distance the second limiting member 420 is screwed in.

[0059] refer to Figure 9 One end of the groove 413a of the base 413 and one end of the groove 414a of the mating block 414 are respectively provided with steps 414a and 414b, which are adapted to the annular protrusion 230 of the rocker pin sample 200. The annular protrusion 230 of the rocker pin sample 200 can be locked in the steps 414a and 414b to improve the fixing effect.

[0060] The groove 413a of the base 413 and the groove 414a of the mating block 414 both have semi-circular cross sections, and the receiving part 411 formed by the two has a circular cross section, which is consistent with the cross-sectional shape of the rocker arm pin sample 200.

[0061] Specifically, first place the unriveted portion 210 of the rocker arm pin sample 200 into Figure 8 The groove 413a of the base 413 is shown. Then the mating block 414 is connected to the base 413. Finally, the second limiting member 420 is screwed into the second limiting hole 412 until the end of the second limiting member 420 abuts against the riveted part 220 of the rocker pin sample 200, so that the rocker pin sample 200 can be pressed onto the base 413.

[0062] The test fixture of the present invention is divided into a first clamping structure 300 and a second clamping structure 400, which can respectively fix the rocker arm sample 100 and the rocker arm pin sample 200, with good fixing effect, which can improve the accuracy and reliability of test results.

[0063] like Figure 10 As shown, the testing method for the compressor riveting rocker arm assembly of the present invention is applied to the test fixture of the compressor riveting rocker arm assembly. The testing method of the present invention includes steps S100 to S500:

[0064] In step S100, the rocker arm pin sample 200 is riveted to the rivet hole 123 of the rocker arm sample 100.

[0065] In step S200, the rocker arm sample 100 is assembled to the first clamping structure 300, and the rocker arm pin sample 200 is assembled to the second clamping structure 400.

[0066] In step S300, the first clamping structure 300 and the second clamping structure 400 are fixed to the testing machine.

[0067] In step S400, the testing machine is turned on, and tensile loads are applied to the first clamping structure 300 and the second clamping structure 400 through the testing machine.

[0068] In step S500, the shear strength of the rocker arm specimen 100 is determined based on the fracture conditions of the rocker arm specimen 100 under different tensile loads.

[0069] Based on three different thickness specifications of rocker arm samples 100 and different selected riveting pressures, the above steps S100 to S500 can be repeated.

[0070] The testing machine of this invention can be a Shimadzu AG-100KN universal testing machine, which can generate tensile force.

[0071] According to the shear test results, shear failure occurred at the riveting joint of rocker arm specimen 100. Figures 11a to 11d As shown, there are four types of fracture surfaces. (Reference) Figure 12a Among them, fracture 3 is a normal fracture, which is pulled apart after necking on both sides. When this type of fracture occurs, the shear stroke is large. Fractures 1, 2 and 4 are all cuts, but the fracture locations are different. After fracture on one side, the structure loses its load-bearing capacity and the load drops sharply. Figure 12b The cross-section of the shear fracture surface is shown, and the shear strength is calculated from the cross-sectional area of ​​the shear fracture surface.

[0072] The shear load-stroke curve obtained by the test method according to the present invention is as follows: Figures 13a to 13e As shown. Since this shear test is a non-standard test and the specimen shape is irregular, the shear load-stroke curve is not converted into a stress-strain curve here.

[0073] However, to compare the influence of riveting process parameters on shear performance, the maximum load of the curve is divided by the cross-sectional area at the fracture location. Rivet holes 123 are concentric circles, and their cross-sectional areas are all obtained through... Figure 12b The calculated strengths are shown in Table 1.

[0074]

[0075] Table 1 Shear test results

[0076] In Table 1, the nominal thickness of rocker arm specimen 100 in group 1 is 1.02 mm, and the riveting pressure is 1.3 MPa. The nominal thickness of rocker arm specimen 100 in group 2 is 1.27 mm, and the riveting pressure is 1.1 MPa. The nominal thickness of rocker arm specimen 100 in group 3 is 1.27 mm, and the riveting pressure is 1.3 MPa. The nominal thickness of rocker arm specimen 100 in group 4 is 1.27 mm, and the riveting pressure is 1.5 MPa. The nominal thickness of rocker arm specimen 100 in group 5 is 1.52 mm, and the riveting pressure is 1.3 MPa.

[0077] The parameters of specimens 1, 2 and 3 in the same group are the same. Each group is tested 3 times, and the average value of the 3 test results is taken as the average strength value of the group.

[0078] When the nominal thickness of the rocker arm sample 100 is 1.27 mm, the strength will increase with the riveting pressure. When the riveting pressure is 1.5 MPa, the average strength reaches 862.78 MPa.

[0079] According to Table 1, the rocker arm specimen 100 with a fixed riveting pressure of 1.3 MPa and a nominal thickness of 1.27 mm has the highest strength.

[0080] The testing method of this invention can simulate the actual stress state of the flexible rocker arm of the VSV mechanism under engine operation, reflecting the actual stress location and direction. This invention measures the shear stress at the fracture of a real flexible rocker arm and characterizes its fracture mode, providing crucial support for the design and use of the flexible rocker arm of the compressor's adjustable stator blades in terms of safety factor, lifespan, and fracture mode.

[0081] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A test sample of a pressurized air compressor riveting rocker arm assembly, for measuring a shearing stress of a riveting joint fracture of a rocker arm in the riveting rocker arm assembly; characterized in that The test sample comprises a rocker arm sample and a rocker pin sample; wherein The rocker arm sample comprises a connecting portion and a test portion; The connecting portion is used for connecting with a test fixture; The test portion is provided with a riveting hole, and the rocker pin sample is riveted in the riveting hole; The rocker arm sample is in a flat plate shape; The material strength of the rocker arm sample is less than that of the rocker pin sample.

2. The test sample of claim 1, wherein, The test portion of the rocker arm sample comprises a test end and a connecting neck connecting the test end and the connecting portion; The outer peripheral edge of the test end is in an arc shape, and the riveting hole and the outer peripheral edge of the test end are concentrically arranged.

3. The test sample of claim 2, wherein, The rocker pin sample comprises an un-riveted portion and a riveted portion; The riveted portion passes through the riveting hole of the rocker arm sample to be riveted with the riveting hole of the rocker arm sample.

4. The test sample of claim 3, wherein, The connecting portion of the rocker arm sample is provided with a connecting hole for connecting with the test fixture; The center of the connecting hole and the center of the riveting hole are located on the central axis of the rocker arm sample.

5. A test sample according to claim 3 or 4, wherein, The material of the rocker arm sample is AMS4911 TC4 titanium alloy; The material of the rocker pin sample is AMS5731 A286 alloy.

6. A test fixture for a pressurized gas compressor swaging rocker arm assembly, comprising: A test fixture for testing the test sample of the pressurized air compressor riveting rocker arm assembly according to any one of claims 3 to 5; The test fixture comprises a first clamping structure for clamping the rocker arm sample and a second clamping structure for clamping the rocker pin sample connected with the rocker arm sample; The first clamping structure and the second clamping structure are connected with a test machine, and the test machine is used for applying a tensile load to the first clamping structure and the second clamping structure.

7. The test fixture of claim 6, wherein, The first clamping structure comprises a first clamping piece and a first limiting piece; The first clamping piece is provided with a first limiting hole through which the first limiting piece can pass, so that the rocker arm sample can be fixed to the first clamping piece by the first limiting piece passing through the first limiting hole and the riveting hole of the rocker arm sample.

8. The test fixture of claim 7, wherein, The first clamping piece is provided with a receiving groove for accommodating at least part of the connecting portion of the rocker arm sample; The connecting portion can be inserted into the receiving groove, the first limiting hole of the first clamping piece penetrates through the receiving groove, and the first limiting hole and the riveting hole of the rocker arm sample are correspondingly arranged, so that the first limiting piece can pass through the riveting hole of the rocker arm sample located in the receiving groove.

9. The test fixture of any one of claims 6 to 8, wherein, The second clamping structure comprises a second clamping piece and a second limiting piece; The second clamping piece is provided with a receiving part for accommodating at least part of the rocker pin sample and a second limiting hole through which the second limiting piece can pass; When the rocker pin sample is located in the receiving part, the second limiting piece and the second limiting hole cooperate to generate a pressing force acting on the rocker pin sample, so as to press the rocker pin sample in the receiving part.

10. The test fixture of claim 9, wherein, The second clamping piece comprises a base and a matching block; wherein The matching block is detachably arranged on the base. The recesses on the fitting block and the recesses on the base are opposite to form the receiving part when the fitting block is arranged on the base; The base is provided with a receiving groove for receiving at least part of the rocker pin sample and the test end of the rocker sample, and the receiving groove and the receiving part are in communication.

11. The test fixture of claim 10, wherein, The second limiting member and the second limiting hole are threadedly connected; The second limiting member can abut against the riveting part of the rocker pin sample, and the second limiting member generates a pressing force acting on the riveting part during the threaded cooperation of the second limiting member and the second limiting hole.

12. A method of testing a pressurized gas canister swaging rocker assembly, the method comprising: The test fixture is applied to the compressor riveting rocker assembly as claimed in any one of claims 6-11; The test method comprises: riveting the rocker pin sample to the riveting hole of the rocker sample; assembling the rocker sample to the first clamping structure and assembling the rocker pin sample to the second clamping structure; fixing the first clamping structure and the second clamping structure to a testing machine; starting the testing machine to apply a tensile load to the first clamping structure and the second clamping structure through the testing machine; determining the shear strength of the rocker sample according to the fracture of the rocker sample under different tensile loads.

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