A kind of cylindrical pin single shear bearing performance detection device suitable for solid launch cabin section connection

Abstract

This invention relates to a device for testing the single-shear load-bearing capacity of cylindrical pins used in solid rocket module connections, belonging to the field of rocket engines. It includes an upper pull plate, a lower pull plate, a locking sleeve, and a cylindrical pin. The lower pull plate is placed vertically. The upper pull plate is placed vertically above the lower pull plate and mates with the side of the lower pull plate. The cylindrical pin is axially and horizontally embedded at the mating point of the upper and lower pull plates. The locking sleeve is fitted onto the outer walls of the upper and lower pull plates. The top of the upper pull plate and the bottom of the lower pull plate are connected to an external universal tensile testing machine. A vertical tensile force is applied to the upper and lower pull plates by the external universal tensile testing machine to test the single-shear load-bearing capacity of the cylindrical pin. This invention solves the problem that existing cylindrical pin shear load-bearing capacity testing devices are not suitable for testing the single-shear load-bearing capacity of cylindrical pins used in solid rocket module connections.

Description

Technical Field

[0001] This invention belongs to the field of rocket engines and relates to a device for testing the load-bearing capacity of a single shear pin used in the connection of solid rocket motor sections. Background Technology

[0002] In multi-pulse solid-state engines, cylindrical pins with external straps are generally used for axial positioning and connection between sections. The length of such cylindrical pins is generally less than twice the pin diameter. The axial load between sections is mainly applied to the outer surface of the cylindrical pin in the form of single shear. Therefore, the single shear load-bearing capacity of the cylindrical pin directly affects the connection reliability of the engine product. Thus, it is crucial to accurately test the single shear load-bearing capacity of the cylindrical pin.

[0003] The current testing device and method for the shear bearing capacity of cylindrical pins are basically modified based on GB / T 13683-1992 "Test Method for Shear Pins". It is more suitable for testing the double shear bearing capacity of pins, but not for the single shear bearing capacity of pins. In addition, it requires that the length of the cylindrical pin be not less than four times the pin diameter. Therefore, this testing device is not suitable for testing the single shear bearing capacity of cylindrical pins used for solid engine compartment connections. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a device for testing the single shear load-bearing capacity of cylindrical pins used in the connection of fixed-engine compartments, thus solving the problem that existing cylindrical pin shear load-bearing capacity testing devices are not suitable for testing the single shear load-bearing capacity of cylindrical pins used in the connection of fixed-engine compartments.

[0005] The solution of the present invention is:

[0006] A device for testing the single-shear load-bearing capacity of a cylindrical pin used in the connection of a fixed-engine compartment includes an upper pull plate, a lower pull plate, a locking sleeve, and a cylindrical pin. The lower pull plate is placed vertically. The upper pull plate is placed vertically above the lower pull plate and abuts against the side of the lower pull plate. The cylindrical pin is axially and horizontally embedded at the joint between the upper and lower pull plates. The locking sleeve is fitted onto the outer walls of the upper and lower pull plates. The top of the upper pull plate and the bottom of the lower pull plate are connected to an external universal tensile testing machine. A vertical tensile force is applied to the upper and lower pull plates by the external universal tensile testing machine to test the single-shear load-bearing capacity of the cylindrical pin.

[0007] In the aforementioned device for testing the load-bearing capacity of a cylindrical pin single shear for connecting fixed-engine compartments, the upper pull plate is an inverted L-shaped plate structure; a first threaded connecting rod section is vertically provided on the top of the upper pull plate; a first mounting hole is provided at the mating side wall of the upper pull plate and the lower pull plate; and a first locking sleeve limiting step is provided on the outer side wall of the upper pull plate.

[0008] In the aforementioned device for testing the load-bearing capacity of a cylindrical pin single shear for connecting fixed-engine compartment sections, the pull-down plate is an L-shaped plate structure; a second threaded connecting rod section is vertically provided at the bottom of the pull-down plate; a second mounting hole is provided at the mating side wall of the pull-down plate and the upper pull-down plate; and a second locking sleeve limiting step is provided on the outer side wall of the pull-down plate.

[0009] In the aforementioned single-shear bearing capacity testing device for cylindrical pins used in the connection of fixed-engine compartments, the upper pull plate and the lower pull plate cooperate to install the cylindrical pin in the first mounting hole and the second mounting hole; after the docking is completed, the locking sleeve is fitted onto the outer wall of the upper pull plate and the lower pull plate for locking; after the upper pull plate and the lower pull plate are docked, the first locking sleeve limiting step and the second locking sleeve limiting step form an annular step; the shaft end of the locking sleeve is fixed and limited by the annular step.

[0010] In the aforementioned device for testing the single-shear bearing capacity of cylindrical pins used in the connection of fixed-engine compartments, the materials of the upper pull plate, lower pull plate, and locking sleeve have higher hardness and strength than those of the cylindrical pin.

[0011] In the aforementioned device for testing the single-shear bearing capacity of a cylindrical pin used in the connection of a fixed-engine compartment, the thickness of the upper and lower pull plates is 1.6 to 2 times the outer diameter of the cylindrical pin; the diameters of the first and second mounting holes are both 0.05 to 0.1 mm larger than the outer diameter of the cylindrical pin; the depths of the first and second mounting holes are both 1 to 2 mm larger than 0.5 times the height of the cylindrical pin; the first and second mounting holes are located at the center of the mating surfaces of the upper and lower pull plates, respectively.

[0012] In the aforementioned device for testing the load-bearing capacity of a single shear pin for connecting a fixed-engine compartment, the thickness of both the first locking sleeve limiting step and the second locking sleeve limiting step is 5mm; the upper surfaces of both the first locking sleeve limiting step and the second locking sleeve limiting step are located 0.75 times the outer diameter of the cylindrical pin below the mounting hole; no locking sleeve limiting step is provided on the mating surface of the first locking sleeve limiting step and the second locking sleeve limiting step.

[0013] In the aforementioned device for testing the load-bearing capacity of a cylindrical pin for connecting fixed-engine compartments, the nominal thread size of both the first threaded connecting rod segment and the second threaded connecting rod segment is M12; the effective thread length is not less than 20mm.

[0014] In the aforementioned device for testing the load-bearing capacity of a cylindrical pin single shear for connecting fixed-engine compartments, the locking sleeve is a hollow cubic structure with openings at both the top and bottom; the wall thickness of the locking sleeve is 5mm.

[0015] In the aforementioned device for testing the load-bearing capacity of a cylindrical pin single shear for connecting fixed-engine compartments, the length and width of the inner surface of the locking sleeve are 0.1-0.2 mm larger than the outer surface contour dimensions of the upper and lower pull plates after they are joined.

[0016] The beneficial effects of this invention compared to the prior art are:

[0017] (1) The present invention uses the form of upper and lower pull plates to install cylindrical pins and perform shear loading, so it can be applied to shear tests of cylindrical pins with different lengths and outer diameters, and is more versatile than the shearing device modified according to the principle of GB / T 13863.

[0018] (2) The present invention adopts the method of upper and lower pull plates and locking sleeve, which can be closer to the actual working conditions of the compartment when the engine product is in service, and can perform single shear load performance testing on the cylindrical pin.

[0019] (3) The present invention provides a device for testing the single shear bearing capacity of cylindrical pins used in the connection of fixed engine compartments, which solves the problem that the existing cylindrical pin shear bearing capacity testing devices are not suitable for testing the single shear bearing capacity of cylindrical pins used in the connection of fixed engine compartments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the cylindrical pin single shear bearing performance testing device of the present invention;

[0021] Figure 2 This is a cross-sectional view of the cylindrical pin single shear bearing performance testing device of the present invention;

[0022] Figure 3 This is a schematic diagram of the upper pull-out plate structure of the present invention;

[0023] Figure 4 This is a schematic diagram of the pull-down plate structure of the present invention;

[0024] Figure 5 This is a schematic diagram of the locking sleeve of the present invention. Detailed Implementation

[0025] The present invention will be further described below with reference to the embodiments.

[0026] This invention provides a device for testing the single shear load-bearing capacity of cylindrical pins used in the connection of fixed-engine compartments, solving the problem that existing cylindrical pin shear load-bearing capacity testing devices are not suitable for testing the single shear load-bearing capacity of cylindrical pins used in the connection of fixed-engine compartments.

[0027] Cylindrical pin single shear bearing capacity testing device, such as Figure 1 , Figure 2As shown, the assembly specifically includes an upper pull plate 1, a lower pull plate 2, a locking sleeve 3, and a cylindrical pin 4. The lower pull plate 2 is placed vertically. The upper pull plate 1 is placed vertically above the lower pull plate 2 and is aligned with the side of the lower pull plate 2. The cylindrical pin 4 is axially and horizontally embedded at the joint between the upper pull plate 1 and the lower pull plate 2. The locking sleeve 3 is fitted onto the outer walls of the upper pull plate 1 and the lower pull plate 2. The top of the upper pull plate 1 and the bottom of the lower pull plate 2 are both connected to an external universal tensile testing machine. A vertical tensile force is applied to the upper pull plate 1 and the lower pull plate 2 using the external universal tensile testing machine to test the single shear bearing capacity of the cylindrical pin 4.

[0028] The materials of the upper pull plate 1, lower pull plate 2, and locking sleeve 3 have higher hardness and strength than those of the cylindrical pin 4.

[0029] like Figure 3 As shown, the upper pull plate 1 is an inverted L-shaped plate structure; a first threaded connecting rod section 11 is vertically provided at the top of the upper pull plate 1; a first mounting hole 12 is provided at the mating side wall of the upper pull plate 1 and the lower pull plate 2; a first locking sleeve limiting step 13 is provided on the outer side wall of the upper pull plate 1. Figure 4 As shown, the pull-down plate 2 has an L-shaped plate structure; a second threaded connecting rod section 21 is vertically provided at the bottom of the pull-down plate 2; a second mounting hole 22 is provided at the side wall where the pull-down plate 2 and the pull-up plate 1 meet; a second locking sleeve limiting step 23 is provided on the outer side wall of the pull-down plate 2.

[0030] The upper pull plate 1 and the lower pull plate 2 cooperate to install the cylindrical pin 4 in the first mounting hole 12 and the second mounting hole 22; after the docking is completed, the locking sleeve 3 is fitted onto the outer wall of the upper pull plate 1 and the lower pull plate 2 for locking; after the upper pull plate 1 and the lower pull plate 2 are docked, the first locking sleeve limiting step 13 and the second locking sleeve limiting step 23 form an annular step; the shaft end of the locking sleeve 3 is fixed and limited by the annular step.

[0031] Specific parameter design:

[0032] The thickness of the upper pull plate 1 and the lower pull plate 2 is 1.6 to 2 times the outer diameter of the cylindrical pin 4; the diameter of the first mounting hole 12 and the second mounting hole 22 is 0.05 to 0.1 mm larger than the outer diameter of the cylindrical pin 4; the depth of the first mounting hole 12 and the second mounting hole 22 is 1 to 2 mm larger than 0.5 times the height of the cylindrical pin 4; the first mounting hole 12 and the second mounting hole 22 are located at the center of the mating surface of the upper pull plate 1 and the lower pull plate 2, respectively.

[0033] The thickness of the first locking sleeve limiting step 13 and the second locking sleeve limiting step 23 is 5mm; the upper surfaces of the first locking sleeve limiting step 13 and the second locking sleeve limiting step 23 are both located 0.75 times the outer diameter of the cylindrical pin 4 below the mounting hole; the mating surface of the first locking sleeve limiting step 13 and the second locking sleeve limiting step 23 is not provided with a locking sleeve limiting step.

[0034] The nominal thread size of the first threaded connecting rod section 11 and the second threaded connecting rod section 21 is M12; the effective thread length is not less than 20mm.

[0035] like Figure 5 As shown, the locking sleeve 3 is a hollow cubic structure with openings at both the top and bottom; the wall thickness of the locking sleeve 3 is 5mm. The length and width dimensions of the inner surface of the locking sleeve 3 are 0.1-0.2mm larger than the outer contour dimensions of the upper pull plate 1 and the lower pull plate 2 after they are joined together.

[0036] Example

[0037] A device for testing the single-shear load-bearing capacity of cylindrical pins used in the connection of fixed-engine compartments is provided. The device allows cylindrical pins of different sizes to be installed in their respective mounting holes via an upper pull plate 1 and a lower pull plate 2, achieving a mating connection. A locking sleeve 3 is installed on the outer surfaces of the upper and lower pull plates, and is fixed and limited by locking sleeve limiting steps 13 and 23 on the outer sides of the upper and lower pull plates. Finally, the device is connected to a universal tensile testing machine via threaded connecting rods 11 and 21 on the upper and lower pull plates to complete the single-shear load-bearing capacity test of the cylindrical pin 4.

[0038] Specifically, the thickness of the upper pull plate 1 is 1.6 to 2 times the pin diameter, including the cylindrical pin 4 mounting hole feature, the locking sleeve limiting feature, and the threaded connecting rod feature;

[0039] The diameter of the mounting hole for the cylindrical pin 4 on the upper pull plate is 0.05mm to 0.1mm larger than the outer diameter of the cylindrical pin 4, and the depth of the mounting hole is 1mm to 2mm larger than 0.5 times the height of the cylindrical pin 4. The center of the mounting hole for the cylindrical pin 4 is located at the center of the mating surfaces of the upper and lower pull plates. The thickness of the limiting step of the locking sleeve of the upper pull plate is 5mm. The position of the upper surface of the step should be 0.75 times the outer diameter of the cylindrical pin 4 below the mounting hole of the cylindrical pin 4 on the upper and lower pull plates (based on the vertical upward direction of the threaded rod of the upper pull plate). The limiting step should be distributed on the three vertical sides of the upper pull plate other than the mating surface. The nominal thread size of the threaded connecting rod of the upper pull plate is M12. The nominal thread diameter can be appropriately increased according to the increase of the outer diameter of the cylindrical pin 4, and the effective thread length is not less than 20mm.

[0040] Specifically, the thickness of the pull-down plate is 1.6 to 2 times the pin diameter, including features such as cylindrical pin 4 mounting holes, locking sleeve limiting features, and threaded mounting rod features;

[0041] The diameter of the mounting hole for the cylindrical pin 4 in the pull-down plate is 0.05mm to 0.1mm larger than the outer diameter of the cylindrical pin 4, and the depth of the mounting hole is 1mm to 2mm larger than 0.5 times the height of the cylindrical pin 4. The center of the mounting hole for the cylindrical pin 4 is located at the center of the mating surfaces of the upper and lower pull-down plates. The thickness of the limiting step of the locking sleeve of the pull-down plate is 5mm. The position of the upper surface of the step should be 0.75 times the outer diameter of the cylindrical pin 4 below the mounting hole of the cylindrical pin 4 in the upper and lower pull-down plates, with the pull-down plate threaded rod pointing vertically downward. The limiting step should be distributed on the three vertical sides of the pull-down plate other than the mating surface. The nominal thread size of the threaded connecting rod of the pull-down plate is M12 or above. The nominal thread diameter can be appropriately increased according to the increase of the outer diameter of the cylindrical pin 4, and the effective thread length is not less than 20mm.

[0042] Specifically, the thickness of the locking sleeve is 5mm. The length and width of the inner surface of the locking sleeve should be 0.1mm to 0.2mm larger than the outer contour of the upper and lower pull plates after they are mated. The height of the locking sleeve should be equal to the distance between the upper surface of the upper pull plate (lower surface of the lower pull plate) and the upper surface of the limiting step (lower surface of the lower pull plate).

[0043] Example 1

[0044] In a specific embodiment of this invention, a device for testing the single shear load-bearing capacity of cylindrical pins used in fixed-section connections was employed. Installed on a universal tensile testing machine, the single shear load-bearing capacity of 24 cylindrical pins with an outer diameter of Ф12mm, an inner diameter of M5, and a height of 11.5mm were tested. The single shear failure load of all products was within the range of 65.95kN to 67.6kN, with a single shear load data dispersion coefficient Cv of 0.82%. This example successfully solved the problem of testing the single shear load-bearing capacity of cylindrical pins with different lengths and outer diameters, with data fluctuation within 1%, indicating valid test data.

[0045] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A device for testing the single-shear bearing capacity of cylindrical pins used in the connection of fixed engine compartment sections, characterized in that: The device includes an upper pull plate (1), a lower pull plate (2), a locking sleeve (3), and a cylindrical pin (4); wherein, the lower pull plate (2) is placed vertically; the upper pull plate (1) is placed vertically above the lower pull plate (2) and is connected to the side of the lower pull plate (2); the cylindrical pin (4) is axially and horizontally embedded at the joint between the upper pull plate (1) and the lower pull plate (2); the locking sleeve (3) is fitted on the outer wall of the upper pull plate (1) and the lower pull plate (2); the top of the upper pull plate (1) and the bottom of the lower pull plate (2) are connected to an external universal tensile testing machine; the upper pull plate (1) and the lower pull plate (2) are subjected to vertical tensile force by the external universal tensile testing machine to realize the single shear bearing capacity test of the cylindrical pin (4); The upper pull plate (1) is an inverted L-shaped plate structure; a first threaded connecting rod section (11) is vertically provided on the top of the upper pull plate (1); a first mounting hole (12) is provided at the mating side wall of the upper pull plate (1) and the lower pull plate (2); a first locking sleeve limiting step (13) is provided on the outer side wall of the upper pull plate (1). The pull-down plate (2) is an L-shaped plate structure; a second threaded connecting rod section (21) is vertically provided at the bottom of the pull-down plate (2); a second mounting hole (22) is provided at the side wall where the pull-down plate (2) and the pull-up plate (1) meet; a second locking sleeve limiting step (23) is provided on the outer side wall of the pull-down plate (2). The locking sleeve (3) is a hollow cubic structure with openings at both the top and bottom ends; The upper pull plate (1) and the lower pull plate (2) cooperate to install the cylindrical pin (4) in the first mounting hole (12) and the second mounting hole (22); after the docking is completed, the locking sleeve (3) is fitted onto the outer wall of the upper pull plate (1) and the lower pull plate (2) for locking; after the upper pull plate (1) and the lower pull plate (2) are docked, the first locking sleeve limiting step (13) and the second locking sleeve limiting step (23) form an annular step; the shaft end of the locking sleeve (3) is fixed and limited by the annular step.

2. The device for testing the single-shear bearing capacity of cylindrical pins used in the connection of fixed-engine compartments according to claim 1, characterized in that: The materials of the upper pull plate (1), lower pull plate (2) and locking sleeve (3) have higher hardness and strength than those of the cylindrical pin (4).

3. The device for testing the single-shear bearing capacity of cylindrical pins used in the connection of fixed-engine compartments according to claim 2, characterized in that: The thickness of the upper pull plate (1) and the lower pull plate (2) is 1.6 to 2 times the outer diameter of the cylindrical pin (4); the diameter of the first mounting hole (12) and the second mounting hole (22) is 0.05 to 0.1 mm larger than the outer diameter of the cylindrical pin (4); the depth of the first mounting hole (12) and the second mounting hole (22) is 1 to 2 mm larger than 0.5 times the height of the cylindrical pin (4); the first mounting hole (12) and the second mounting hole (22) are located at the center of the mating surface of the upper pull plate (1) and the lower pull plate (2), respectively.

4. The device for testing the single-shear bearing capacity of a cylindrical pin used in the connection of a fixed engine compartment according to claim 3, characterized in that: The thickness of the first locking sleeve limiting step (13) and the second locking sleeve limiting step (23) is 5mm; the upper surfaces of the first locking sleeve limiting step (13) and the second locking sleeve limiting step (23) are both located at 0.75 times the outer diameter of the cylindrical pin (4) below the mounting hole; the mating surfaces of the first locking sleeve limiting step (13) and the second locking sleeve limiting step (23) are not provided with locking sleeve limiting steps.

5. The device for testing the single-shear bearing capacity of a cylindrical pin used in the connection of a fixed engine compartment according to claim 4, characterized in that: The nominal thread size of both the first threaded connecting rod segment (11) and the second threaded connecting rod segment (21) is M12; the effective thread length is not less than 20mm.

6. The device for testing the single-shear bearing capacity of cylindrical pins used in the connection of fixed-engine compartments according to claim 1, characterized in that: The wall thickness of the locking sleeve (3) is 5mm.

7. The device for testing the single-shear bearing capacity of cylindrical pins used in the connection of fixed-engine compartments according to claim 6, characterized in that: The length and width of the inner surface of the locking sleeve (3) are 0.1-0.2 mm larger than the outer surface contour of the upper pull plate (1) and the lower pull plate (2) after they are joined.

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