A method for measuring the torsion and tension relationship and the friction coefficient of a single-sided mounting fastener

Abstract

The application discloses a kind of single-sided installation fastener torsion and measurement method of friction coefficient, not only can accurately measure the tightening torque T of single-sided installation threaded fastener in whole installation process, pre-tightening force F, threaded friction torque Tt, torsion angle and rotation speed etc., and can be obtained according to the relevant formula of torsion and tension relationship of threaded fastening torque coefficient K, threaded friction coefficient μ t , friction torque T of rotating support surface b (T b =T-T t ), support surface friction coefficient μ b And other parameters, simultaneously also solve the disassembly problem after installation is completed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of measuring the connection of threaded fasteners, and particularly relates to a method for measuring the torque-tension relationship and friction coefficient of single-sided installation fasteners. BACKGROUND

[0002] A typical threaded fastener connection refers to a connection structure composed of a bolt, a nut and a clamped part, as shown in the drawing. In engineering, the installation of a threaded fastener is usually achieved by applying a certain tightening torque or torsion angle or pre-tightening force to the bolt or nut. During the installation or disassembly process, the driving side rotates, and the other side generally needs to be stopped. The feature is that it is generally completed on both sides of the clamped part. The torque-tension relationship of the fastener can be obtained on an ordinary torsion-tension testing machine. Figure 1

[0003] In some specific cases in engineering, the fastener can only be inserted into the installation hole from one side of the clamped part and fixed. At this time, a single-sided installation fastener is needed. A commonly used single-sided installation fastener includes a pin body B1, a core rod bolt B2, a pin sleeve B3, and a nut B4, as shown in the drawing. The inside of the pin body B1 and the pin sleeve B3 is a through hole for passing through the core rod bolt B2. The load end of the pin body B1 is a conical body, and the other end is a conical inclined surface that is connected to the inner cone of the pin sleeve B3. The other end of the pin sleeve B3 is connected to the nut B4, and the connecting surface has teeth. When the core rod bolt B2 is tightened, the nut B4 is stopped. The core rod bolt B2 penetrates the pin body B1, the pin sleeve B3 and the nut B4 to engage. Rotating the core rod bolt B2 and the nut B4 produces axial movement, pushing the pin sleeve B3 to move towards the pin body B1, and gradually expanding the outer circle of the inner cone of the pin sleeve B3. When the expanded end surface of the pin sleeve B3 contacts the clamped part, end face bending deformation occurs. When the tightening torque reaches a predetermined value, the deformation of the pin sleeve B3 reaches the best state, and the loading head of the core rod bolt B2 is broken, as shown in the drawing, achieving the purpose of single-sided installation and clamping the clamped part (B5, B6). Figure 2 Figure 3

[0004] The measurement of the torque-tension relationship and friction coefficient of a single-sided installation fastener is the basis for guiding its design and installation. The tightening torque of a single-sided installation fastener is converted into clamping force, which is usually referred to as pre-tightening force. The conversion relationship between the tightening torque and the pre-tightening force is referred to as the torque coefficient, which can be represented by the following formula:

[0005] T = kdF

[0006] ​​​k is called the torque coefficient, d is the nominal diameter of the bolt or nut, T is the tightening torque, and F is the pre-tightening force. In engineering, for a threaded fastening connection at a specific position, the designer needs to determine the pre-tightening force required during installation based on conditions such as load, and then calculate the required tightening torque or torsion angle through the formula, and the obtained tightening torque or torsion angle is used to guide the installation operation.

[0007] The torsional relationship of the threaded fastening can also be expressed by the following formula:

[0008]

[0009] where T is the tightening torque, μ b is the support surface friction coefficient, r b is the effective radius of the support surface, p is the thread pitch, μ t is the thread friction coefficient, r t is the effective radius of the thread, and a is the thread angle. The first term on the right side of the above formula is the support surface friction torque, which can be represented by the symbol T b ; the second term is the equivalent thread friction torque, which can be represented by the symbol T t , that is:

[0010] T b = Fμ b r b

[0011]

[0012] In the prior art, the detection characteristics of the mechanical properties of single-sidedly installed fasteners are single-sided installation and loading test. However, due to the asymmetric stress caused by single-sided contact, bending moment error is easily caused. At the same time, most devices only support static / quasi-static loading, and dynamic load simulation is insufficient, which easily leads to an increase in fatigue life prediction deviation. In addition, the prior art also has the defect that the test piece is not easy to disassemble after single-sided installation and loading.

[0013] Therefore, it is necessary to provide a method for accurately measuring the torsional relationship and friction coefficient of a single-sidedly installed fastener, which is easy to disassemble the test piece. SUMMARY

[0014] The purpose of the present application is to provide a method for measuring the torsional relationship and friction coefficient of a single-sidedly installed fastener to solve the problems of the prior art.

[0015] In order to achieve the above-mentioned purpose, the present application specifically adopts the following technical solutions:

[0016] This invention provides a method for measuring the torsion-tension relationship and friction coefficient of a single-sided fastener. The method employs a measuring device consisting of a fixed support body, a tension-torsion composite sensor, an adjusting wedge, an adjusting screw, a stop clamp, a movable support body, a support plate, a stop pressure plate, a clamp, and a rotational torque and torsion angle sensor, and includes the following steps:

[0017] S1. Fix the fixed support body in place. The fixed support body, adjusting wedge, adjusting screw and movable support body form a loading frame.

[0018] S2. The tension-torsion composite sensor is rigidly mounted on the end face of the fixed bearing body, with axial and circumferential constraints.

[0019] S3. Install the stop clamp on the inner end face of the tension-torsion composite sensor to provide axial and circumferential constraints.

[0020] S4. The movable support body moves along the axial direction of the specimen and is rigidly positioned with the fixed support body. The position can be controlled by adjusting the wedge and adjusting the screw.

[0021] S5. The bearing plate is rigidly installed on the end face of the movable bearing body, with axial and circumferential constraints;

[0022] S6. Insert the single-sided mounting fastener into the bearing plate hole, then install the stop plate, and tighten the end face of the single-sided mounting fastener with screws to achieve axial positioning and circumferential anti-rotation of the specimen.

[0023] S7. Connect the rotational torque and torsion angle sensors to the single-sided mounting fastener loading head via a clamp;

[0024] S8. By adjusting the rotation of the lead screw, the movable support body is moved horizontally. After adjusting to the required distance between the movable support body and the fixed support body, the specimen is loaded.

[0025] S9. Tightening torque T and torsion angle are obtained through rotational torque and torsion angle sensors; preload F and thread friction torque T of the specimen are obtained through tension-torsion composite sensor. t ; through preload F, tightening torque T, thread torque T t The torque coefficient K is calculated, or the thread friction coefficient μ is calculated. t Alternatively, the friction coefficient μ of the supporting surface can be calculated. b ;

[0026] S10. When the experiment ends and the loading head of the single-sided fastener breaks off, turn the adjusting screw down to the lowest position. At this time, the distance between the movable bearing and the fixed bearing is the smallest, and the preload of the single-sided fastener is released. Separate the nut of the single-sided fastener from the core rod bolt.

[0027] Furthermore, the fixed support body is a curved plate structure, the lower end face of the fixed support body can be connected to the application platform, the vertical surface of the fixed support body is perpendicular to the lower end face, the center of the fixed support body is a stepped hole, the stepped hole cooperates with the tension-torsion composite sensor, and is rigidly constrained by the tension-torsion composite sensor through circumferentially distributed fastening screws.

[0028] Furthermore, the tension-torsion composite sensor has a cage-like structure, and the right end face of the tension-torsion composite sensor is a stepped shaft structure, with the outer step rigidly connected to the fixed support body; the left end face of the tension-torsion composite sensor is an inner stepped through hole structure, and the inner stepped through hole is used to install the stop clamp.

[0029] Furthermore, the inner stepped through hole of the tension-torsion composite sensor is fitted with a stop clamp via a pin, thereby constraining the tension-torsion composite sensor axially and circumferentially. The end face of the inner stepped hole of the tension-torsion composite sensor is perpendicular to the center and has two evenly distributed cylindrical pin holes for mounting two cylindrical pins, thus constraining the circumferential rotation of the stop clamp. This allows the tension-torsion composite sensor to measure the preload force F and thread torque T of a fastener mounted on one side. t .

[0030] Furthermore, the stop clamp has a stepped bowl-shaped structure, and its outer end face has two symmetrically distributed grooves that engage with the two cylindrical pins of the tension-torsion composite sensor to transmit the thread torque T of the single-sided fastener. t For the tension-torsion composite sensor; the inner end face of the stop clamp is perpendicular to the center, the central through hole is clearance-fitted with the outer cylinder of the single-sided mounting fastener, and the preload F and thread torque T of the single-sided mounting fastener are specified. t The force is transmitted to a tension-torque composite sensor via a stop clamp, which measures the preload F and thread torque T of the single-sided fastener. t .

[0031] Furthermore, the center of the movable support body is a stepped through hole, and the stepped end face of the movable support body is perpendicular to the stepped through hole, which is used to install the support plate. It is rigidly connected by screws, and the stepped hole is coaxial with the tension-torsion composite sensor.

[0032] Furthermore, the bearing plate is a disc structure with a conical through hole at the center. The conical surface mates with the conical surface at the end of the specimen to constrain the axial movement of the specimen. Four smooth holes are symmetrically arranged on the end face for installing fastening screws. The inner hole of the bearing plate is slightly larger than the outer diameter of the specimen to allow the specimen to pass through. The end face of the bearing plate has two threaded holes for fastening the stop plate.

[0033] Furthermore, the stop plate has two through holes symmetrically distributed at both ends, with the center distance being the same as that of the threaded hole on the end face of the bearing disc. It is connected to the bearing disc by screws. By controlling the tightening force of the screws, the pressure of the raised step on the end face of the stop plate on the single-sided fastener can be controlled, thereby constraining the rotation of the nail body of the single-sided fastener.

[0034] Further, the fixed carrier, the adjusting wedge, the adjusting screw and the movable carrier constitute a bearing frame, the movable carrier moves left and right along the guide column group and the guide rail group through the cooperation of the adjusting screw and the adjusting wedge; the guide rods of the guide column group are rigidly installed on the end face of the movable carrier and symmetrically distributed on the four corners of the movable carrier and perpendicular to the movable carrier, and the linear bearings of the four sets of guide column groups are rigidly installed on the end face of the fixed carrier and perpendicular to the fixed carrier, to realize the parallel displacement of the movable carrier relative to the fixed carrier;

[0035] The guide rail group is installed on the two inclined surfaces of the adjusting wedge, the sliders on both sides are respectively installed on the end faces of the fixed carrier and the movable carrier, the vertical movement of the adjusting wedge drives the horizontal movement of the movable carrier, and the relative position of the movable carrier and the fixed carrier can be controlled by adjusting the vertical position of the adjusting wedge;

[0036] The end of the adjusting screw is connected with the upper end face of the adjusting wedge by a pin, the adjusting screw can rotate freely, the vertical movement of the adjusting screw drives the vertical movement of the adjusting wedge, the upper end of the adjusting screw is engaged with the nut fixed to the fixed carrier, and the horizontal position of the movable carrier is moved by rotating the adjusting screw and moving the adjusting wedge.

[0037] Further, in step S9, the torque coefficient K is calculated by the pre-tightening force F, the tightening torque T and the following formula:

[0038] K = T / (D · F)

[0039] Wherein, D is the diameter of the single-side installed fastener nut.

[0040] The thread friction coefficient μ is calculated by the thread torque T t and the following formula: t

[0041]

[0042] Wherein, p is the single-side installed fastener thread pitch, r t is the effective radius of the thread surface, and α is the thread form angle;

[0043] The support surface friction torque T t is obtained by subtracting the thread torque T b from the tightening torque T, and the support surface friction coefficient μ b is calculated based on the following formula:

[0044] μ b = T b / (F · r b ) ​

[0045] wherein, r b is the effective friction radius of the support surface.

[0046] Compared with the prior art, the present application has the following advantages:

[0047] The method for measuring the torsion and tension relationship and the friction coefficient of the single-sided mounting fastener can not only accurately measure the data such as the tightening torque T, the pre-tightening force F, the thread friction torque T t , the torsion angle and the rotation speed of the single-sided mounting threaded fastener during the entire mounting process, but also can calculate the torque coefficient K, the thread friction coefficient μ t , the friction torque T b (T b =T-T t ) of the rotating support surface, the support surface friction coefficient μ b and other parameters according to the relevant formula of the torsion and tension relationship of the threaded fastening, and solves the dismounting problem after the mounting is completed. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 is a schematic diagram of the connection structure of a typical threaded fastener; Figure 1 wherein, A1 is a bolt, A2 is a nut, A3 is a clamped piece 1, and A4 is a clamped piece 2.

[0049] Figure 2 is a schematic diagram of the structure of a commonly used single-sided mounting fastener (test piece); Figure 2 wherein, B1 is a pin body, B2 is a core rod bolt, B3 is a pin sleeve, and B4 is a nut.

[0050] Figure 3 is a schematic diagram of the structure of a broken head after loading of a commonly used single-sided mounting fastener. Figure 3 wherein, B2 is a core rod bolt, B5 is a clamped piece 3, and B6 is a clamped piece 4.

[0051] Figure 4 is a schematic diagram of the installation of the tensile and torsional composite sensor and the fixed carrier provided by the embodiment of the present application.

[0052] Figure 5 is a schematic diagram of the installation of the tensile and torsional composite sensor and the stop clamp provided by the embodiment of the present application.

[0053] Figure 6 is a schematic diagram of the installation of the movable carrier and the carrier disc provided by the embodiment of the present application. Figure 6 wherein, (a) is a side view, and (b) is a schematic diagram of the structure.

[0054] Figure 7 is a schematic diagram of the installation of the carrier disc and the stop press plate provided by the embodiment of the present application. Figure 7In the drawings, (a) is a side view, (b) is a front view, and (c) is a right side view.

[0055] Figure 8 The structure schematic diagram of the loading framework provided by the embodiment of the present application is shown. Figure 8 In the drawings, (a) is a left view, (b) is a front view, and (c) is a right side view.

[0056] Figure 9 The structure schematic diagram of the measuring device for the torsion and tension relationship and the friction coefficient of the single-sided installation fastener provided by the embodiment of the present application is shown. Figure 1 .

[0057] Figure 10 The structure schematic diagram of the measuring device for the torsion and tension relationship and the friction coefficient of the single-sided installation fastener provided by the embodiment of the present application is shown. Figure 2 . DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0059] The commonly used single-sided installation fastener at present, as shown in FIG. 1, comprises a nail body B1, a core rod bolt B2, a nail sleeve B3, and a nut B4. The inside of the nail body B1 and the nail sleeve B3 is a through hole for passing through the core rod bolt B2. The bearing end of the nail body B1 is a conical body, and the other end conical inclined surface is connected with the inner taper of the nail sleeve B3. The other end of the nail sleeve B3 is connected with the nut B4, and the connecting surface is provided with teeth. The nut B4 is stopped when the core rod bolt B2 is tightened. The core rod bolt B2 penetrates through the nail body B1, the nail sleeve B3, and the nut B4 to engage. The rotation of the core rod bolt B2 and the nut B4 produces axial movement, pushes the nail sleeve B3 to move towards the nail body B1, and gradually expands the outer circle of the inner taper of the nail sleeve B3. When the expanded end surface of the nail sleeve B3 contacts the clamped part, the end surface is bent and deformed. When the tightening torque reaches a predetermined value, the deformation of the nail sleeve B3 reaches the best state, and the loading head of the core rod bolt B2 is broken (as shown in FIG. 2), so as to achieve the purpose of single-sided installation and clamping of the clamped part (B5, B6). Figure 3 Figure 9

[0060] The measuring method for the torsion and tension relationship and the friction coefficient of the single-sided installation fastener provided by the present application is aimed at the commonly used single-sided installation fastener. The measuring device (as shown in FIG. 3 and FIG. 4) is composed of a fixed bearing body 1, a tension and torsion composite sensor 2, an adjusting wedge block 3, an adjusting lead screw 4, a stop clamp 5, a movable bearing body 6, a bearing disc 7, a stop pressing plate 8, a clamp 9, and a rotary torque and torsion angle sensor 10. Figure 4 and​​10 (As shown) and the following steps:

[0061] S1. Fix the fixed support body 1 in place. The fixed support body 1, the adjusting wedge block 3, the adjusting screw 4 and the movable support body 6 form a loading frame.

[0062] Specifically, such as Figure 4 As shown, the fixed support body 1 is a curved plate structure. The lower end face of the fixed support body 1 can be connected to the application platform. The vertical surface of the fixed support body 1 is perpendicular to the lower end face. The center of the fixed support body 1 is a stepped hole. The stepped hole cooperates with the tension-torsion composite sensor 2 and is rigidly constrained by the tension-torsion composite sensor 2 through circumferentially distributed fastening screws.

[0063] S2. The tension-torsion composite sensor 2 is rigidly mounted on the end face of the fixed support body 1 by screws, so that the fixed end of the tension-torsion composite sensor 2 is constrained to the fixed support body 1 in the axial and circumferential directions, so that the tension-torsion composite sensor can measure the preload and torque of the loading end.

[0064] Specifically, such as Figure 5 As shown, the tension-torsion composite sensor 2 has a cage-like structure. The right end face of the tension-torsion composite sensor 2 is a stepped shaft structure, and the outer step is rigidly connected to the fixed bearing 1. The left end face of the tension-torsion composite sensor 2 is an inner stepped through hole structure, and the inner stepped through hole is used to install the stop clamp 5.

[0065] S3. Install the stop clamp 5 on the inner end face of the tension-torsion composite sensor 2 using a pin. The stop clamp 5 provides axial and circumferential constraints to the tension-torsion composite sensor 2, enabling the tension-torsion composite sensor to measure the preload (F) and thread torque (T) of a fastener (test piece) mounted on one side. t ).

[0066] Specifically, such as Figure 6 As shown, the inner stepped through hole of the tension-torsion composite sensor 2 is fitted with a stop clamp 5 via a pin, thereby constraining the tension-torsion composite sensor 2 axially and circumferentially. The end face of the inner stepped hole of the tension-torsion composite sensor 2 is perpendicular to the center and has two evenly distributed cylindrical pin holes for installing two cylindrical pins, thus constraining the circumferential rotation of the stop clamp 5. This allows the tension-torsion composite sensor 2 to measure the preload F and thread torque T of a fastener mounted on one side. t .

[0067] The stop clamp 5 has a stepped bowl-shaped structure, and its outer end face has two symmetrically distributed grooves. It is clamped on the two cylindrical pins of the tension-torque composite sensor 2 to transmit the thread torque T of the fastener installed on one side. t The tension-torsion composite sensor 2 is provided; the inner end face of the stop clamp 5 is perpendicular to the center, the central through hole is in clearance fit with the outer cylinder of the single-sided mounting fastener, and the preload F and thread torque T of the single-sided mounting fastener are specified.t The pre-tightening force F and the thread torque T of the single-sided installation fastener are measured by the tension-torsion composite sensor 2 through the transmission of the stop clamp 5 to the tension-torsion composite sensor 2 t .

[0068] S4, the movable carrier 6 is axially displaced along the test piece, and is rigidly positioned with the fixed carrier 1 through a screw, and the position is controllable through adjustment of the wedge block 3 and the adjusting screw 4.

[0069] Specifically, as shown in Figure 7 , the center of the movable carrier 6 is a stepped through hole, and the stepped end face of the movable carrier 6 is perpendicular to the stepped through hole, which is used to install the bearing disc 7, and is rigidly connected through a screw, and the stepped hole is coaxial with the tension-torsion composite sensor 2.

[0070] S5, the bearing disc 7 is rigidly installed on the end face of the movable carrier 6 through a screw, and is axially and circumferentially constrained.

[0071] Specifically, as shown in Figure 7 , the bearing disc 7 is a disc structure, the center of which is a conical through hole, and the conical surface cooperates with the conical surface of the end of the test piece to constrain the axial movement of the test piece, and the end face is symmetrically arranged with four light holes for installing fastening screws for constraining the circumferential movement of the test piece; the inner hole of the bearing disc 7 is slightly larger than the outer diameter of the test piece, and is used to pass through the test piece; the end face of the bearing disc is provided with two threaded holes for fastening the stop pressing plate 8.

[0072] S6, the single-sided installation fastener is installed in the hole of the bearing disc 7, and then the stop pressing plate 8 is installed, the end face of the single-sided installation fastener is pressed through a screw, and the axial positioning and circumferential rotation of the test piece are realized.

[0073] Specifically, as shown in Figure 8 , the stop pressing plate 8 is symmetrically distributed with two through holes at both ends, and the center distance is the same as that of the threaded hole of the bearing disc end face, and is connected with the bearing disc through a screw, and the pressure of the end face protruding step of the stop pressing plate 8 on the single-sided installation fastener can be controlled by controlling the pressing force of the screw, so as to constrain the rotation of the nail body of the single-sided installation fastener.

[0074] S7, the rotary torque and torsion angle sensor 10 is connected with the loading head of the single-sided installation fastener through the clamp 9.

[0075] The loading head of the single-sided installation fastener (test piece) is transmitted through the rotary torque and torsion angle sensor 10 and the clamp 9, and the rotary torque and torsion angle sensor 10 is used to measure the tightening torque (T) and torsion angle of the single-sided installation fastener (test piece).

[0076] S8, the movable carrier 6 is horizontally moved by rotating the adjusting screw 4, and after the required distance between the movable carrier 6 and the fixed carrier 1 is adjusted, the test piece is loaded.

[0077] Specifically, such as ​ As shown, the fixed support body 1, the adjusting wedge block 3, the adjusting screw 4 and the movable support body 6 form a support frame. The movable support body 6 moves left and right along the guide column group 11 and the guide rail group 12 through the cooperation of the adjusting screw 4 and the adjusting wedge block 3.

[0078] The guide rods of the guide column assembly 11 are rigidly installed on the end face of the movable support body 6 and symmetrically distributed at the four corners of the movable support body 6, and perpendicular to the movable support body 6. The linear bearings of the four sets of guide column assemblies 11 are rigidly installed on the end face of the fixed support body 1 and perpendicular to the fixed support body 1, so as to realize the parallel displacement of the movable support body 6 relative to the fixed support body 1.

[0079] The guide rail assembly 12 is installed on the two inclined surfaces of the adjusting wedge block 3. The sliders on both sides are respectively installed on the end faces of the fixed support body 1 and the movable support body 6. The vertical movement of the adjusting wedge block 3 drives the horizontal movement of the movable support body 6. By adjusting the vertical position of the adjusting wedge block 3, the relative position of the movable support body 6 and the fixed support body 1 can be controlled.

[0080] The end of the adjusting screw 4 is connected to the upper end face of the adjusting wedge 3 and is constrained by a pin. The adjusting screw 4 can rotate freely. The up and down movement of the adjusting screw 4 causes the adjusting wedge 3 to move up and down accordingly. The upper end of the adjusting screw 4 is engaged with the nut fixed to the fixed bearing 1. By rotating the adjusting screw 4, the adjusting wedge 3 moves up and down accordingly, thereby moving the horizontal position of the movable bearing 6.

[0081] S9. The tightening torque T and torsion angle are obtained through the rotational torque and torsion angle sensor 10, and the preload F and thread friction torque T of the specimen are obtained through the tension-torsion composite sensor. t ; through preload F, tightening torque T, thread torque T t The torque coefficient K is calculated, or the thread friction coefficient μ is calculated. t Alternatively, the friction coefficient μ of the supporting surface can be calculated. b .

[0082] Specifically, the torque coefficient K is calculated using the preload F, the tightening torque T, and the following formula:

[0083] K = T / (D·F)

[0084] Where D is the diameter of the single-sided fastener nut.

[0085] Through the thread torque T t The thread friction coefficient μ is calculated using the following formula. t :

[0086]

[0087] Wherein, p is the single-sided installation fastener thread pitch, r t is the effective radius of the thread surface, and a is the thread form angle.

[0088] The tightening torque T is subtracted from the thread torque T t to obtain the support surface friction torque T b , and the support surface friction coefficient μ is calculated based on the following formula: b :

[0089] μ b = T b / (F·r b )

[0090] Wherein, r b is the effective friction radius of the support surface.

[0091] S10, when the experiment ends and the loading head of the single-sided installation fastener is broken, the adjusting screw 4 is rotated downward to the lowest position, at which time the distance between the movable carrier 6 and the fixed carrier 1 is the smallest, and the pre-tightening force of the single-sided installation fastener is unloaded, so that the nut and the core rod bolt of the single-sided installation fastener can be easily separated.

[0092] The position of the adjusting wedge 3 is controlled by rotating the adjusting screw 4, that is, the distance between the movable carrier 6 and the fixed carrier 1 is controlled; for small load models, the torque for driving the adjusting screw 4 is not large, and manual operation can be easily twisted, and a manual driving mode is adopted; for models with larger loads, the torque for driving the adjusting screw 4 is relatively large, and manual operation is relatively laborious at this time, and an electric driving mode is adopted.

[0093] In summary, the test method provided by the present application can not only accurately measure the tightening torque T, pre-tightening force F, thread friction torque Tt, torsion angle and rotation speed and other data of the single-sided installation threaded fastener during the entire installation process, but also can calculate the torque coefficient K, thread friction coefficient μ t , the friction torque T b of the rotating support surface (T b =T-T t ), the support surface friction coefficient μ b and other parameters according to the relevant formula of the torsion and tension relationship of the threaded fastening, and simultaneously solves the disassembly problem after installation.

[0094] The above is only a preferred embodiment of the present application, and is not used to limit the present application, and the patent protection scope of the present application is subject to the claims, and any equivalent structural changes made by using the contents of the specification and drawings of the present application should also be included in the protection scope of the present application.

Claims

1. A method of measuring the torsional relationship and coefficient of friction of a single-sided installation fastener, characterized by, The measurement device is composed of a fixed carrier (1), a tension-torsion composite sensor (2), an adjusting wedge (3), an adjusting screw (4), a stop clamp (5), a movable carrier (6), a bearing disc (7), a stop pressing plate (8), a clamp (9) and a rotating torque and torsion angle sensor (10), and the following steps are adopted: S1, the fixed carrier (1) is fixed, the fixed carrier (1), the adjusting wedge (3), the adjusting screw (4) and the movable carrier (6) form a loading frame; S2, the tension-torsion composite sensor (2) is rigidly installed on the end face of the fixed carrier (1), so that the fixed end of the tension-torsion composite sensor (2) is axially and circumferentially constrained to the fixed carrier (1); S3, the stop clamp (5) is installed on the inner end face of the tension-torsion composite sensor (2), so that the stop clamp (5) is axially and circumferentially constrained to the tension-torsion composite sensor (2); S4, the movable carrier (6) is axially displaced along the test piece and is rigidly positioned with the fixed carrier (1), and the position is controllable through the adjusting wedge (3) and the adjusting screw (4); S5, the bearing disc (7) is rigidly installed on the end face of the movable carrier (6), so that the bearing disc (7) is axially and circumferentially constrained to the movable carrier (6); S6, the single-sided installation fastener is installed in the hole of the bearing disc (7), and then the stop pressing plate (8) is installed, the end face of the single-sided installation fastener is pressed by the screw, so as to realize the axial positioning and circumferential rotation stopping of the test piece; S7, the rotating torque and torsion angle sensor (10) is connected with the loading head of the single-sided installation fastener through the clamp (9); S8, the rotating of the adjusting screw (4) drives the horizontal movement of the movable carrier (6), and after the required distance between the movable carrier (6) and the fixed carrier (1) is adjusted, the test piece is loaded; S9. Tightening torque T and torsion angle are obtained through rotational torque and torsion angle sensors; preload F and thread friction torque T of the specimen are obtained through tension-torsion composite sensor. t ; through preload F, tightening torque T, thread torque T t The torque coefficient K is calculated, or the thread friction coefficient μ is calculated. t Alternatively, the friction coefficient μ of the supporting surface can be calculated. b ; S10, when the experiment is finished and the loading head of the single-sided installation fastener is twisted off, the adjusting screw (4) is rotated to the lowest position, at this time, the distance between the movable carrier (6) and the fixed carrier (1) is the smallest, the pre-tightening force of the single-sided installation fastener is unloaded, and the nut and the core rod bolt of the single-sided installation fastener are separated.

2. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein The fixed carrier (1) is a bent plate structure, the lower end face of the fixed carrier (1) can be connected with an application rack, the vertical surface of the fixed carrier (1) is perpendicular to the lower end face, the center of the fixed carrier (1) is a stepped hole, the stepped hole cooperates with the tension-torsion composite sensor (2), and the tension-torsion composite sensor (2) is rigidly constrained by the circumferentially distributed fastening screws.

3. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein The tension-torsion composite sensor (2) is a cage structure, the right end face of the tension-torsion composite sensor (2) is a stepped shaft structure, the outer step is rigidly connected with the fixed carrier (1); the left end face of the tension-torsion composite sensor (2) is an inner stepped through hole structure, and the inner stepped through hole is used to install the stop clamp (5).

4. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 3, wherein The inner step through hole of the tensile-torsional composite sensor (2) is installed with the pin stop clamp (5), so that the stop clamp (5) is axially and circumferentially constrained with the tensile-torsional composite sensor (2), the inner step hole end surface of the tensile-torsional composite sensor (2) is perpendicular to the center, and is uniformly distributed with two cylindrical pin holes for installing two cylindrical pin shafts, thereby constraining the circumferential rotation of the stop clamp (5), so that the tensile-torsional composite sensor (2) can measure the pre-tightening force F and the thread torque T of the single-side installed fastener t .

5. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein The stop clamp (5) is a stepped bowl structure, and the outer end surface of the stop clamp (5) is provided with two symmetrical and uniformly distributed grooves, which are clamped on the two cylindrical pin shafts of the tension-torsion composite sensor (2) to transmit the thread torque T of the single-sided mounting fastener t The inner end surface of the stop clamp (5) is perpendicular to the center, and the center through hole is matched with the outer cylindrical gap of the single-sided mounting fastener, and the pre-tightening force F and the thread torque T of the single-sided mounting fastener t The pre-tightening force F and the thread torque T of the single-sided mounting fastener are transmitted to the tension-torsion composite sensor (2) through the stop clamp (5) and measured by the tension-torsion composite sensor (2) t .

6. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein The center of the movable carrier (6) is a stepped through hole, the stepped end face of the movable carrier (6) is perpendicular to the stepped through hole, and the stepped through hole is used to install the bearing disc (7) and is rigidly connected by screws, and the stepped hole is coaxial with the tension-torsion composite sensor (2).

7. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein The bearing disc (7) is a disc structure, the center is a conical through hole, the conical surface cooperates with the end conical surface of the test piece to constrain the axial movement of the test piece, and the end surface is symmetrically provided with four light holes for installing fastening screws; the inner hole of the bearing disc (7) is slightly larger than the outer diameter of the test piece, and is used for passing through the test piece; the end surface of the bearing disc is provided with two threaded holes for fastening the stop pressing plate (8).

8. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein The stop pressing plate (8) is symmetrically distributed with two through holes at both ends, the center distance is the same as that of the threaded holes on the end surface of the bearing disc, and is connected with the bearing disc through screws. By controlling the pressing force of the screw, the pressure of the end surface protruding step of the stop pressing plate (8) on the single-sided installation fastener can be controlled, so as to constrain the rotation of the shank of the single-sided installation fastener.

9. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein The fixed bearing body (1), the adjusting wedge block (3), the adjusting lead screw (4) and the movable bearing body (6) constitute a bearing frame, the movable bearing body (6) moves left and right along the guide column group (11) and the guide rail group (12) through the cooperation of the adjusting lead screw (4) and the adjusting wedge block (3); the guide rods of the guide column group (11) are rigidly installed on the end surface of the movable bearing body (6) and are symmetrically distributed on the four corners of the movable bearing body (6) and are perpendicular to the movable bearing body (6), and the linear bearings of the four sets of guide column groups (11) are rigidly installed on the end surface of the fixed bearing body (1) and are perpendicular to the fixed bearing body (1), realizing the parallel displacement of the movable bearing body (6) relative to the fixed bearing body (1); The guide rail group (12) is installed on the two inclined surfaces of the adjusting wedge block (3), the sliders on both sides are installed on the end surfaces of the fixed bearing body (1) and the movable bearing body (6), and the vertical movement of the adjusting wedge block (3) drives the horizontal movement of the movable bearing body (6), and the relative position of the movable bearing body (6) and the fixed bearing body (1) can be controlled by adjusting the vertical position of the adjusting wedge block (3); The end of the adjusting lead screw (4) is connected with the upper end surface of the adjusting wedge block (3) by a pin, the adjusting lead screw (4) can rotate freely, the vertical movement of the adjusting lead screw (4) drives the vertical movement of the adjusting wedge block (3), and the upper end of the adjusting lead screw (4) is engaged with the nut fixed to the fixed bearing body (1), by rotating the adjusting lead screw (4), the adjusting wedge block (3) moves vertically, and then the horizontal position of the movable bearing body (6) is moved.

10. The method of measuring the torsion-lax relationship and the coefficient of friction of a single-sided mounting fastener according to claim 1, wherein In step S9, the torque coefficient K is calculated by the pre-tightening force F, the tightening torque T and the following formula: K = T / (D·F) Wherein, D is the diameter of the nut of the single-sided installation fastener; By the thread torque T t and the thread friction coefficient μ is calculated by the following formula t : where p is the single-sided mounting fastener thread pitch, r t is the effective radius of the thread face, and a is the thread form angle; Subtract the thread torque T from the tightening torque T t Obtain the support surface friction torque T b , and then calculate the support surface friction coefficient μ based on the following formula b : μ b = T b / (F·r b ) where r b is the effective friction radius of the support surface.

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