A non-torsion preload loading device and method

Abstract

The present invention provides a non-torsion preload loading device and method, belonging to the technical field of spacecraft mechanisms. The device comprises: a locking rod and a threaded sleeve loading assembly, a thrust bearing, a sensor and a nut which are arranged coaxially therewith and are sequentially installed thereon from bottom to top; the threaded sleeve loading assembly comprises an inner support frame and an outer support frame, and the inner support frame can be rotated, ascended or descended relative to the outer support frame; the moving ring of the thrust bearing is connected to the inner support frame, and the stationary ring of the thrust bearing is connected to the sensor; the nut locks the sensor above the thrust bearing. The non-torsion preload loading device of the present invention is suitable for rod-shaped clamping, is easy to operate, can display the preload in real time, and the clamped device does not bear the torsional load, thereby ensuring the relative position relationship between the multiple components in the clamped device.

Description

Technical Field

[0001] The present invention belongs to the technical field of spacecraft mechanisms, and specifically relates to a non-torsion preload loading device and method, which can prevent a clamped device from being subjected to torque, especially when it involves a serial clamping device and needs to ensure the precise relative position relationship between components. Background Art

[0002] In order to resist the mechanical environment of the launch phase, the moving parts of the spacecraft mechanism need to be fixed on a fixed support, generally using a push rod; to ensure the reliability of the fixation, a certain preload force will be applied to the push rod.

[0003] At present, conventional preload force loading methods are locking nut angle method or locking nut torque control method. Both methods convert the rotational motion between the locking nut and the push rod in the clamping device into the tensile motion of the push rod. When using this method, the clamping device must bear the torque of the locking nut and there is a tendency for relative dislocation.

[0004] When there are position requirements for the pressed device, especially when a push rod is used to press multiple components, and the positions of the multiple components need to be accurately maintained, such as when the pressed device is a reel-type extension rod mechanism, the reel-type extension rod mechanism uses a push rod to press the start-up deployment component, the auxiliary support component, and the elastic reel together. The start-up deployment component is a sliding pair mechanism composed of three sleeves. If the upper and lower base positions are misaligned, the start-up deployment component will be stuck and cannot be deployed. Therefore, conventional torsional preload loading devices and methods are not suitable for preload loading of such mechanisms.

[0005] Guan Facai and others from Shenyang Aerospace Xinguang Group Co., Ltd. disclosed a non-torsion preload loading device (CN105149930A), the driving source of which uses a hydraulic cylinder and a hydraulic pump to achieve the stretching of the push rod. However, due to the heavy weight and large size of the hydraulic system, it is more suitable for large preload loading of large mechanisms, but not suitable for preload loading of small deployment mechanisms. In addition, there is no report on the preload loading method for the loading device. A corresponding loading method needs to be proposed for a dedicated loading device to ensure the correctness of the preload loading. Summary of the invention

[0006] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a non-torsion preload loading device and method, so that the clamped device does not bear the torsional load and the relative position relationship between the multiple components of the clamped device is guaranteed.

[0007] The present invention is achieved through the following technical solutions:

[0008] A first aspect of the present invention provides a non-torsion preload loading device, the non-torsion preload loading device comprising: a locking rod and a threaded sleeve loading assembly, a thrust bearing, a sensor and a nut which are coaxially arranged therewith and sequentially installed thereon from bottom to top;

[0009] The threaded sleeve loading assembly comprises an inner support frame and an outer support frame, wherein the inner support frame can be rotated to rise or fall relative to the outer support frame;

[0010] The moving ring of the thrust bearing is connected to the inner support frame, and the stationary ring of the thrust bearing is connected to the sensor;

[0011] The nut locks the sensor above the thrust bearing.

[0012] A further improvement of the present invention is that a hemispherical joint support and a hemispherical joint are further provided between the sensor and the nut;

[0013] The lower end surface of the hemispherical joint support contacts the upper end surface of the sensor, the hemispherical surface of the hemispherical joint is installed in the hemispherical joint support, and the lower end surface of the nut contacts the upper end surface of the hemispherical joint.

[0014] A further improvement of the present invention is that a large gasket is installed between the thrust bearing and the sensor;

[0015] The lower end surface of the large gasket contacts the upper end surface of the fixed ring of the thrust bearing, and the lower end surface of the sensor contacts the upper end surface of the large gasket.

[0016] A further improvement of the present invention is that the inner support frame and the outer support frame are both cylindrical structures;

[0017] The upper end of the inner support frame is a closed end, and the lower end is an open end. An external thread is provided on the outer wall between the closed end and the open end, and the outer diameter of the portion between the closed end and the open end is smaller than the outer diameter of the closed end; the outer diameter of the closed end is larger than the inner diameter of the outer support frame;

[0018] A central through hole coaxial with the inner support frame is provided at the closed end of the inner support frame, and the diameter of the central through hole is smaller than the inner diameter of the inner support frame;

[0019] An internal thread is provided on the inner wall of the outer support frame; the external thread on the inner support frame is connected with the internal thread on the outer support frame;

[0020] The length of the inner support frame in the axial direction is smaller than the length of the outer support frame in the axial direction;

[0021] The closed end of the inner support frame is located above the upper end surface of the outer support frame, and the open end of the inner support frame is located in the central through hole of the outer support frame and is higher than the lower end surface of the outer support frame;

[0022] An annular groove coaxial with the inner support frame is provided on the upper end surface of the closed end of the inner support frame; the moving ring of the thrust bearing is installed in the annular groove;

[0023] The upper end of the locking rod is located above the nut, and the lower end is located in the central through hole of the outer support frame;

[0024] An external thread is provided on the upper portion of the locking rod, which can cooperate with the nut;

[0025] A connecting hole coaxial with the locking rod is provided at the lower end of the locking rod, and an internal thread is provided on the inner wall of the connecting hole.

[0026] A further improvement of the present invention is that holes perpendicular to the central axis of the inner support frame are respectively opened on both sides of the closed end of the inner support frame, and the two holes are 180 degrees apart on the circumference;

[0027] A loading arm is mounted in each hole;

[0028] The external threads on the inner support frame and the internal threads on the outer support frame are both fine pitch threads;

[0029] The sensor adopts an annular pressure sensor;

[0030] The thrust bearing adopts a thrust ball bearing.

[0031] A second aspect of the present invention provides a method for loading a torsion-free preload, the method comprising:

[0032] Step 1: Obtain the tension F on the top rod of the clamped device A and the strain value of the top rod ε A the relationship between;

[0033] Step 2: Obtain the reading F of the sensor on the non-torsion preload loading device c and the strain value of the top rod ε c the relationship between;

[0034] Step 3: The tension F of the top rod obtained in step 1 A and the strain value of the top rod ε A The relationship between and the sensor reading F obtained in step 2 c and the strain value of the top rod ε c The relationship between the sensor and the c The tension F on the top rod A the relationship between;

[0035] Step 4: According to the designed preload, use the sensor reading F obtained in step 3 c The tension F on the top rod A The relationship between the sensor is used to determine the reading of the sensor, and then the non-torsion preload loading device is used to achieve the compression of the compressed device.

[0036] A further improvement of the present invention is that the operation of step 1 includes:

[0037] Step 101: Take out the push rod of the pressing device, and stick two groups of strain gauges on the push rod, each group of strain gauges includes two strain gauges, the centers of the two strain gauges in each group are located in the same plane perpendicular to the central axis of the push rod, and the centers of the two strain gauges in each group are 180 degrees apart on the circumference; the line connecting the centers of the two strain gauges in the first group is perpendicular to the line connecting the centers of the two strain gauges in the second group;

[0038] Step 102: Install the clamping rod on the universal material testing machine, load it step by step from 0N to 500N, then unload it step by step from 500N to 0N, record the strain value of each strain gauge after each level of loading and calculate the sum of the strain values ​​of each group of strain gauges, record the strain value of each strain gauge after each level of unloading and calculate the sum of the strain values ​​of each group of strain gauges, and then perform the following operations:

[0039] If the sum of the strain values ​​of the two groups of strain gauges is not equal at least once or the strain value of at least one strain gauge is not 0 when unloaded to 0N, it is determined to be abnormal, and the pasting position of the strain gauge is adjusted at this time, and the process returns to step 102;

[0040] If the sum of the strain values ​​of the two groups of strain gauges is equal, and the strain values ​​of each strain gauge are all 0 when unloading to 0N, the preloading is completed and the process goes to step 103;

[0041] Step 103: Perform formal loading: Use gradient loading method to obtain different tensile forces F A The corresponding strain value ε A , and then the tension F on the top rod is obtained by least squares fitting A and the strain value of the top rod ε A The relationship between: F A =f(ε A ).

[0042] A further improvement of the present invention is that the operation of step 2 includes:

[0043] Step 201: remove the ejector rod in the clamped device from the universal material testing machine and install it into the clamped device;

[0044] Step 202: Install the non-torsion preload loading device on the device to be pressed; set the initial preload force F B Equal to the design preload F 设计 ;

[0045] Step 203: Determine the preload force F B Is it greater than F? 设计 +1000, if yes, then go to step 204, if no, then rotate the loading arm lever in the reverse direction to return the loading device to the unloaded state, and then rotate the loading arm lever forward to make the sensor reading reach F B , then tighten the lock nut to reduce the sensor reading to F B - Set the value and record the sensor reading F at this time c and strain value ε c , then calculate F B =F B +P, return to step 203.

[0046] Step 204: Obtain the sensor reading F by least squares fitting c and the strain value of the top rod ε c The relationship between: F c =f(ε c ).

[0047] A further improvement of the present invention is that the operation of step three includes:

[0048] Step 301: Based on F A =f(ε A ) and F c =f(ε c ) relationship, and obtain the relationship between the sensor reading and the tension on the push rod: F A =f(F c );

[0049] Step 302: F 设计 As F A Substitute F A =f(F c ) to obtain the corresponding sensor reading F c , the sensor reading F c As the applied force F 施加 .

[0050] A further improvement of the present invention is that the operation of step 4 includes:

[0051] Step 401: installing the non-torsion preload loading device on the compressed device;

[0052] Step 402: Rotate the loading arm to lift the inner support frame and stretch the ejector rod;

[0053] Step 403: When the sensor reading is (F 施加 +100)N, stop rotating the loading arm;

[0054] Step 404: Tighten the locking nut. When the sensor indicates F 施加 Stop tightening the lock nut;

[0055] Step 405: Rotate the loading arm in the opposite direction, and stop rotating when the reading of the sensor is less than 50N; at this time, loosen the locking rod, separate the locking rod from the top rod, and remove the above-mentioned non-torsion preload loading device.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) The non-torsion preload loading device of the present invention is suitable for rod-shaped compression, is easy to operate, can display the preload in real time, and the compressed device does not bear the torsion load, thereby ensuring the relative position relationship between multiple components in the compressed device;

[0058] (2) The method for converting the actual loading preload force and the indication of the loading device based on the strain of the push rod proposed in the present invention is simple in process, easy to operate, and has high accuracy in preload force loading. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a structural schematic diagram of the non-torsion preload loading device of the present invention;

[0060] Figure 2 It is a structural schematic diagram of a typical serial clamping mechanism applicable to the non-torsion preload loading device of the present invention;

[0061] Figure 3 is a flowchart of the steps of the method of the present invention;

[0062] Figure 4 A schematic diagram of the bonding position of the strain gauge when calibrating the mandrel of the present invention;

[0063] Figure 5 A flowchart of the steps for calibrating the ejector rod of the present invention;

[0064] Figure 6 It is the preload force calibration data in the embodiment of the present invention. DETAILED DESCRIPTION

[0065] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0066] The present invention proposes a torsion-free preload device and a preload method, which prevents the clamped device from being subjected to torque during the preload loading process, thereby ensuring the relative position relationship of various components in the clamped device; and overcomes the problems that conventional preload loading cannot directly display the loaded preload value and the preload loading result cannot be judged.

[0067] The non-torsion preload loading device of the present invention comprises: a locking rod 10 and a threaded sleeve loading assembly, a thrust bearing, a sensor and a nut 9 which are coaxially arranged therewith and sequentially installed thereon from bottom to top; the threaded sleeve loading assembly comprises an inner support frame 6 and an outer support frame 5, and the inner support frame 6 can rotate, rise or fall relative to the outer support frame 5; the moving ring of the thrust bearing is connected to the inner support frame 6, and the stationary ring of the thrust bearing is connected to the sensor; the nut 9 locks the sensor above the thrust bearing.

[0068] Furthermore, since the cross-sectional area of ​​the thrust bearing is relatively small, in order to increase the contact area between the sensor and the thrust bearing, a large gasket 4 is provided between the thrust bearing and the sensor. In order to prevent the locking rod 10 from being subjected to bending moment, a hemispherical joint support 2 and a hemispherical joint 1 are provided between the sensor and the nut 9. The thrust bearing preferably adopts a thrust ball bearing, and the sensor adopts a pressure sensor.

[0069] Specifically, Figure 1 As shown, the non-torsion preload loading device of the present invention comprises a locking rod and a threaded sleeve loading assembly, a thrust ball bearing 8, a large gasket 4, a pressure sensor 3, a hemispherical joint support 2, a hemispherical joint 1, and a nut 9, which are coaxially arranged with the locking rod 10 from bottom to top. The nut 9, the hemispherical joint 1, the hemispherical joint support 2, the pressure sensor 3, the large gasket 4, and the thrust ball bearing 8 are sequentially sleeved on the outside of the locking rod 10 from top to bottom.

[0070] Embodiments of the present invention are as follows:

[0071] [Example 1]

[0072] The threaded sleeve loading assembly includes an inner support frame 6, an outer support frame 5 and a loading arm 7. The inner support frame 6 and the outer support frame 5 are both cylindrical structures. The upper end of the inner support frame 6 is a closed end, and the lower end is an open end. An external thread is arranged on the outer wall between the closed end and the open end, and the outer diameter of the portion between the closed end and the open end is smaller than the outer diameter of the closed end, that is, an annular step is formed on the upper portion of the outer surface of the inner support frame 6. The outer diameter of the closed end is larger than the inner diameter of the outer support frame 5. A central through hole coaxial with the closed end of the inner support frame 6 is provided, and the diameter of the central through hole is smaller than the inner diameter of the inner support frame (that is, the diameter of the hole in the portion between the closed end and the open end).

[0073] The outer support frame 5 is a cylindrical structure, and an internal thread is provided on its inner wall. The outer diameter of the portion between the closed end and the open end of the inner support frame 6 is the same as the inner diameter of the outer support frame, and the external thread of the portion is connected to the internal thread of the outer support frame. The length of the inner support frame 6 in the axial direction is smaller than the length of the outer support frame in the axial direction.

[0074] The inner support frame 6 and the outer support frame 5 are installed coaxially. After installation, the closed end of the inner support frame 6 is located above the upper end surface of the outer support frame 5, that is, the above-mentioned annular step is located above the upper end surface of the outer support frame, and the loading arm rods 7 are respectively installed on both sides of the closed end. The two loading arm rods 7 are installed in a straight line 180 degrees apart on the circumference.

[0075] The loading arm is installed as follows:

[0076] Two holes perpendicular to the central axis of the inner support frame 6 are formed at the closed end thereof, and the two holes are 180 degrees apart on the circumference, and a loading arm 7 is installed in each hole. An internal thread can be provided in the hole, and an external thread can be provided at one end of the loading arm 7. The loading arm 7 is connected to the hole through the internal and external threads, or the loading arm 7 can be fixed to the closed end of the inner support frame by screws.

[0077] The open end of the inner support frame 6 is located in the central through hole of the outer support frame 5 and is higher than the lower end surface of the outer support frame 5, ensuring that when working with the clamped device, only the outer support frame is in contact with the clamped device, and the inner support frame is not in contact with the clamped device. At the same time, it is necessary to ensure that the inner and outer support frames have a certain thread matching length, so as to provide an effective lifting height of the inner and outer support frame assemblies. Preferably, the matching threads between the inner and outer support frames adopt fine pitch threads, which ensures that when the loading arm rotates at the same angle, the lifting height of the inner and outer support frame assemblies is relatively small, and the rotation angle is easy to control.

[0078] [Example 2]

[0079] An annular groove coaxial with the inner support frame 6 is provided on the upper end surface of the closed end, and the moving ring of the thrust ball bearing 8 is installed in the annular groove. The lower end surface of the large gasket 4 contacts the upper end surface of the fixed ring of the thrust ball bearing 8, the lower end surface of the pressure sensor 3 contacts the upper end surface of the large gasket, the lower end surface of the hemispherical joint support contacts the upper end surface of the pressure sensor, the hemispherical surface of the hemispherical joint 1 is installed in the hemispherical joint support 2, and the lower end surface of the nut 9 contacts the upper end surface of the hemispherical joint 1.

[0080] The function of the hemispherical joint 1 is to ensure that the locking rod is only subjected to tensile stress but not bending moment. If the hemispherical joint is not provided, when the components connected in series on the locking rod are not parallel to each other, the locking rod will be subjected to bending moment. After the hemispherical joint is provided, the non-parallel parts of the parts can be adjusted to ensure that the locking rod is not subjected to bending moment.

[0081] After installation, the central axes of the nut, the hemispherical joint, the hemispherical joint support, the pressure sensor, the large gasket, and the thrust ball bearing are all located on the same straight line with the central axis of the locking rod, that is, the various components are coaxially arranged.

[0082] [Example 3]

[0083] The upper end of the locking rod is located above the nut, and the lower end is located in the central through hole of the outer support frame. A connecting hole coaxial with the locking rod is provided at the lower end of the locking rod, and an internal thread is provided on the inner wall of the connecting hole, and the internal thread is used to connect with the external thread on the upper end of the top rod of the clamped mechanism.

[0084] Preferably, the locking rod comprises a small diameter section and a large diameter section which are connected in sequence from top to bottom, the diameter of the small diameter section is smaller than the inner diameter of the central through hole on the closed end of the inner support frame, and the diameter of the large diameter section is larger than the inner diameter of the central through hole on the closed end of the inner support frame, but smaller than the inner diameter of the inner support frame. An external thread is provided on the upper part of the small diameter section for connection with a nut, and the threaded section is longer than the part where the nut is locked. A connecting hole coaxial with the large diameter section is provided, and an internal thread is provided on the inner wall of the connecting hole, thereby ensuring that the locking rod can be connected to the top rod through internal and external threads.

[0085] The pressure sensor adopts a common commercial annular pressure sensor, which has its own force value display.

[0086] When using, Figure 1 The device of the present invention is installed in Figure 2In the existing clamped device (i.e., the reel-type extension rod mechanism) shown in the figure, the clamped device includes a locking nut 201, a push rod (also called a clamping rod) 202, a clamping unlocking device 203, and an auxiliary support assembly 204. A locking release fixing hole 2024 is provided at the lower end of the push rod. An external thread is provided at the top end of the push rod 202, which can be connected to the internal thread in the connecting hole at the bottom end of the locking rod in the device of the present invention. The external support frame and the device of the present invention Figure 2 The diameters of the auxiliary support components 204 in the device shown are the same. In actual installation, the outer support frame in the device of the present invention is placed Figure 2 On the upper auxiliary support assembly in. Figure 2 It is a device to be pressed, that is, the object to be served; the device of the present invention is directly placed on the device to be pressed and directly serves the device to be pressed. When working, the device of the present invention applies a pulling force to the device to be pressed, which is equivalent to pressing the outer part of the device to be pressed, and the top rod of the device to be pressed is pulled upward by the locking rod, so as to realize the function of pressing the surrounding movable parts together by the top rod.

[0087] Specifically, the device of the present invention is combined with Figure 2 The connection method of the clamped device shown is as follows:

[0088] 1. Connect the bottom end of the locking rod in the device of the present invention to the top end of the push rod through internal and external threads, that is, directly tighten the locking rod onto the push rod 202;

[0089] 2. Then, the other parts of the device of the present invention are sequentially sleeved on the locking rod, and the outer support frame of the device of the present invention is directly placed on the auxiliary support assembly 204 of the compressed device.

[0090] 3. After the various components of the device of the present invention are assembled, the nut of the device of the present invention is tightened onto the locking rod.

[0091] [Example 4]

[0092] like Figure 3 As shown, the method of the present invention comprises:

[0093] Step 1: Calibrate the relationship between the stress and strain of the mandrel: Paste the strain gauge on the mandrel, use a universal material testing machine to perform a tensile test on the mandrel, test the strain value of the mandrel when it is subjected to different tensile forces (i.e. preload), and obtain the tensile force F of the mandrel. A The relationship between the strain value of the mandrel and the

[0094] Step 2: Calibrate the relationship between the sensor reading and the mandrel strain: Install the non-torsion preload loading device of the present invention on the pressed device, still use the mandrel with the strain gauge attached in step 1, use the non-torsion preload loading device of the present invention to apply the preload, and test the sensor reading F on the non-torsion preload loading device of the present invention. c The relationship between the strain value of the mandrel and the

[0095] Step 3: The tension F on the top rod obtained in step 1 A The relationship between the strain value of the push rod and the sensor reading F obtained in step 2 c The relationship between the strain value of the push rod and the relationship between the indication of the sensor of the device of the present invention and the tension (i.e., preload) on the push rod is obtained. Based on this relationship, the loading value of the loading device is obtained according to the designed preload.

[0096] Step 4: According to the design preload (this force is a certain F A value, such as 1000N), determine the sensor reading (this force is a certain F c Value, such as 1400N, this 1400N is determined by the relationship in step three), that is, the specified value (that is, the indication of the sensor, that is, the 1400N assumed above), rotate the loading arm to make the indication of the sensor reach the specified value, and realize the clamping of the clamped device, as follows: first, apply a pulling force that is greater than a certain value of the design preload, and the value is generally controlled at 50N~200N (that is, 50-200N greater than the preload); then, tighten the locking nut of the clamped device so that the indication of the sensor is the reading corresponding to the design preload.

[0097] [Example 5]

[0098] Furthermore, if Figure 5 As shown, the step 1 includes the following steps:

[0099] Step 101: Take out the push rod of the clamping device, and stick two sets of strain gauges on the push rod. Each set of strain gauges includes two strain gauges, and the two strain gauges are symmetrically distributed on the push rod. Figure 5 The first set of strain gauges in the embodiment includes a first strain gauge 2021 and a second strain gauge (in Figure 5 The second group of strain gauges includes a third strain gauge 2022 and a fourth strain gauge 2023; the two groups of strain gauges are arranged at an interval of 180 degrees; the two groups of strain gauges are arranged at similar heights in the axial direction of the top rod, and the distance between the two groups cannot exceed 10 cm; the two strain gauges in each group must be strictly controlled to be at the same height.

[0100] like Figure 4As shown, the centers of the two strain gauges in each group are located in the same plane perpendicular to the central axis of the mandrel, and the centers of the two strain gauges in each group are 180 degrees apart on the circumference, and the two groups of strain gauges are 90 degrees apart, that is, the line connecting the centers of the two strain gauges in the first group is perpendicular to the line connecting the centers of the two strain gauges in the second group. When calculating the strain value, the average value of the two strain gauges in one group is selected as the strain value ε on the mandrel (ε below A、 ε B、 ε c The average value of the strain values ​​of the two strain gauges in the same group is taken separately. Since the strain values ​​of the two groups of strain gauges are guaranteed to be consistent, the average value of the two strain gauges in the same group is the same as the average value of the four strain gauges. Therefore, the average value of the strain values ​​of the two strain gauges in the same group can be used. ).

[0101] Step 102: Install the clamping rod on the universal material testing machine. First, test the strain values ​​corresponding to different preload forces on the top rod from 0 to 500N, load at 100N per level, and then unload step by step until 0, for example, 200N, 300N, 400N, 500N, and then unload to 400N, 300N, 200N, 100N until 0, each 100N is a level, record the strain values ​​of each strain gauge after each level of loading and calculate the sum of the strain values ​​of each group of strain gauges, record the strain values ​​of each strain gauge after each level of unloading and calculate the sum of the strain values ​​of each group of strain gauges, and then perform the following operations:

[0102] If the sum of the strain values ​​of the two groups of strain gauges is not equal at least once or the strain value of at least one strain gauge is not 0 when unloaded to 0N, it is determined to be abnormal, and the pasting position of the strain gauge is adjusted at this time, and the process returns to step 102;

[0103] If the sum of the strain values ​​of the two groups of strain gauges is equal (i.e., the sum of the strain values ​​of the first strain gauge and the second strain gauge in the first group after each level of loading and each level of unloading is equal to the sum of the strain values ​​of the third strain gauge and the fourth strain gauge in the second group), and the strain values ​​of each strain gauge are 0 when unloading to 0N, then the preloading is completed and the process goes to step 103.

[0104] Figure 5 The "data interpretation" in the test is to determine whether the sum of the strain values ​​of the two sets of strain gauges is equal, and whether each strain value is 0 when unloaded to 0N.

[0105] Step 103: Carry out formal loading. When the preload force is F 设计 When the actual loading preload is generally (F 设计 +1000)N; Gradient loading method is adopted for loading, and the interval of loading gradient is 100N~200N. The formal loading is generally from 0.8F 设计 ~(F设计 +1000)N, for example 0.8F 设计 +100, 0.8F 设计 +200, 0.8F 设计 +300 until F 设计 +1000. This way different loading forces F are obtained A The corresponding strain value ε A (Whenever a loading force is applied, the strain values ​​of the two strain gauges in the first or second group of strain gauges are obtained, and the average of the two strain values ​​is taken as the strain value corresponding to the loading force. Different loading forces correspond to different strain values.) The relationship between stress and strain is obtained by least squares fitting: F A =f(ε A ).

[0106] [Example 6]

[0107] Furthermore, the step 2 includes the following steps:

[0108] Step 201: remove the ejector rod in the clamped device from the universal material testing machine and install it into the clamped device, and the two sets of strain gauges continue to remain on the ejector rod;

[0109] Step 202: Install the non-torsion preload loading device of the present invention on the clamped device: first, thread the locking rod and the push rod together, then pass the outer support frame through the locking rod, directly place it on the upper surface of the auxiliary support assembly, and adjust the position of the outer support frame to ensure that the outer support frame is coaxial with the locking rod; then, screw the inner support frame into the outer support frame, install the loading arm on the inner support frame, and then sequentially insert the thrust ball bearing, the large gasket, the pressure sensor, the hemispherical joint support, and the hemispherical joint into the locking rod, and then lock the nut; set the initial preload force F B Equal to the design preload F 设计 ;

[0110] Step 203: Determine the preload force F B Is it greater than F? 设计 +1000, if yes, then go to step 204, if no, then rotate the loading arm lever in the reverse direction to return the loading device to the unloaded state, and then rotate the loading arm lever forward to make the sensor reading reach F B , then tighten the lock nut to reduce the sensor reading to F B - Set the value and record the sensor reading F at this time c and strain value ε c , then calculate F B =F B +P, return to step 203.

[0111] The sensor reading load also adopts the step loading method, with the loading gradient P ranging from 100N to 200N. Generally, the initial recording F B Equal to the design preload F 设计 , and then load until (F 设计 +1000)N.

[0112] The loading method is as follows: rotate the loading arm forward, at this time the loading arm drives the inner support frame to rotate, the inner support frame drives the moving ring of the thrust bearing to rotate together, other parts do not rotate, and there is no torque on the locking rod. When the inner support frame rotates, the external thread on it rotates and rises along the internal thread of the outer support frame, which is equivalent to lifting the inner support frame upward, and the locking rod is also lifted upward with the inner support frame. Since the lower end of the locking rod is connected to the upper end of the clamping rod, the lifting of the locking rod will generate a pulling force on the clamping rod, that is, a preload force F is applied to the clamped device. B , the corresponding strain value of the top rod ε B At this time, manually tighten the locking nut of the clamped device to reduce the sensor reading by the set value (such as 100N) (lifting the inner support frame is equivalent to pulling the push rod upward. Since the locking rod and the push rod are connected by threads, the two are a combination. The locking nut is installed on the push rod. At this time, tighten the locking nut on the clamped device to pull the push rod upward. This is equivalent to redistributing the force values ​​on the locking rod and the push rod, and the pressure sensor displays the force value on the upper locking rod. Therefore, tightening the locking nut on the clamped device will reduce the pressure sensor reading at this time), stop tightening the locking nut, and record the sensor reading F at this time. c (i.e. F c =F B -100) and the strain value of the top rod ε c The value by which the sensor reading is reduced by tightening the locking nut (i.e., the set value) depends on the pre-tightening of the locking nut and can be adjusted according to actual conditions. Generally, the set value is controlled between 50N and 200N, and 100N is used in this embodiment.

[0113] Step 204: Obtain the relationship between the sensor reading and strain (F c =f(ε c ).

[0114] That is, before each level of loading, the loading arm is rotated in the opposite direction to return the non-torsion preload loading device of the present invention to the unloaded state, that is, when the sensor reading is 0N, and then loaded to the reading of the sensor corresponding to the level, and then the locking nut is tightened to reduce the sensor reading to the set value.

[0115] For example: Take the loading gradient P as 100, take the set value as 100, first reverse the loading arm to return the loading device to the unloaded state, first apply FB , then tighten the lock nut to F B -100, then reversely rotate the loading arm to return the loading device to the unloaded state, and then apply F B +100, then tighten the lock nut to reduce to F B , then reverse the loading arm to return the loading device to the unloaded state, and then re-apply F B +200, then tighten the lock nut to reduce to F B +100, then reversely rotate the loading arm to return the loading device to the unloaded state, and so on, and finally load to (F 设计 +1000), then tighten the lock nut down to F 设计 +900, each time the locking nut is tightened, the readings of different sensors corresponding to different strain values ​​are recorded, so that the readings of different sensors F are obtained c and strain value ε c Then, the relationship between the sensor reading and strain is obtained by least squares fitting (F c =f(ε c ).

[0116] [Example 7]

[0117] Furthermore, the step three includes the following steps:

[0118] Step 301: Based on F A =f(ε A ) and F c =f(ε c ) relationship, and obtain the relationship between the preload force on the mandrel and the reading of the loading device sensor, that is, F A =f(F c );

[0119] Specifically, get F A =f(F c ) is as follows: A At 0.8F 设计 ~(F 设计 +1000)N, for example, F A1 , F A2 , F A3 …, through F A =f(ε A ) relationship to calculate the corresponding strain values ​​ε1, ε2, ε3…; then substitute the values ​​of ε1, ε2, ε3… into the formula F c =f(ε c ), we can calculate F c1 , F c2 , F c3 …, and finally, through the least squares method, we can get FA =f(F c )’s relationship.

[0120] Step 302: According to the obtained F A =f(F c ) relationship, find the design estimated preload force F 设计 The corresponding sensor reading F 施加 .

[0121] [Embodiment 8]

[0122] Further, step 4 shown includes the following steps:

[0123] Step 401: Install a non-torsion preload loading device according to step 202;

[0124] Step 402: Rotate the loading arm to lift the inner support frame and stretch the ejector rod;

[0125] Step 403: When the reading of the sensor of the loading device is (F 施加 +100)N, stop rotating the loading arm;

[0126] Step 404: Tighten the locking nut. When the reading of the sensor of the loading device is F 施加 Stop tightening the lock nut;

[0127] Step 405: Rotate the loading arm in the opposite direction, and stop rotating when the reading of the sensor is less than 50N; at this time, release the locking rod, separate the locking rod from the top rod, remove the device of the present invention, and complete the loading.

[0128] A specific application of the method of the present invention is as follows:

[0129] The clamped device is a reel-type extension rod mechanism, which needs to apply a preload force of no less than 1000N. Through calibration, the reading loaded on the sensor each time is obtained to be 1200N, which can ensure that the applied preload force is no less than 1000N. The specific loading method is: first load the sensor to an reading of 1200N, then tighten the locking nut so that the sensor reading is 1100N, and finally, unload the device of the present invention to complete the loading. In the calibration process of this example, loading is performed at intervals of 100N, and the preload force is calibrated to 2000N. Among them, the actual loading force on the push rod corresponding to the reading of the sensor each time loading, and the actual loading force on the push rod after tightening the locking nut are as follows Figure 6 As shown. Figure 6 It can be obtained that when the sensor reading is 1200N, the actual preload force on the push rod is 1158.7N; when the locking nut is tightened, the actual preload force on the push rod is 1039.1N, which meets the requirement of not less than 1000N.

[0130] The loading device of the present invention adopts a screw connection method of the inner and outer support frames, and adopts a thrust ball bearing to convert the rotational movement of the loading arm into a stretching action on the push rod, thereby achieving a linear stretching of the push rod and avoiding the generation of torque on the push rod during the loading process. The loading preload force range that the loading device can achieve is 100N to 5000N.

[0131] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the application methods and principles disclosed in the present invention, and it is not limited to the method described in the above specific implementation mode of the present invention. Therefore, the method described above is only preferred and does not have a restrictive meaning.

Claims

1. A non-torsion preload loading device, characterized in that: The non-torsion preload loading device comprises: a locking rod and a threaded sleeve loading assembly, a thrust bearing, a sensor and a nut which are arranged coaxially therewith and are sequentially installed thereon from bottom to top; The threaded sleeve loading assembly comprises an inner support frame and an outer support frame, wherein the inner support frame can be rotated to rise or fall relative to the outer support frame; The moving ring of the thrust bearing is connected to the inner support frame, and the stationary ring of the thrust bearing is connected to the sensor; The nut locks the sensor above the thrust bearing; The inner support frame and the outer support frame are both cylindrical structures; The upper end of the inner support frame is a closed end, and the lower end is an open end. An external thread is provided on the outer wall between the closed end and the open end, and the outer diameter of the portion between the closed end and the open end is smaller than the outer diameter of the closed end; the outer diameter of the closed end is larger than the inner diameter of the outer support frame; A central through hole coaxial with the inner support frame is provided at the closed end of the inner support frame, and the diameter of the central through hole is smaller than the inner diameter of the inner support frame; An internal thread is provided on the inner wall of the outer support frame; the external thread on the inner support frame is connected with the internal thread on the outer support frame; The length of the inner support frame in the axial direction is smaller than the length of the outer support frame in the axial direction; The closed end of the inner support frame is located above the upper end surface of the outer support frame, and the open end of the inner support frame is located in the central through hole of the outer support frame and is higher than the lower end surface of the outer support frame; An annular groove coaxial with the inner support frame is provided on the upper end surface of the closed end of the inner support frame; the moving ring of the thrust bearing is installed in the annular groove; The upper end of the locking rod is located above the nut, and the lower end is located in the central through hole of the outer support frame; An external thread is provided on the upper portion of the locking rod, which can cooperate with the nut; A connecting hole coaxial with the locking rod is provided at the lower end of the locking rod, and an internal thread is provided on the inner wall of the connecting hole; The sensor adopts a pressure sensor; the thrust bearing adopts a thrust ball bearing; The central axes of the nut, the pressure sensor and the thrust ball bearing are all located on the same straight line as the central axis of the locking rod.

2. The non-torsion preload loading device according to claim 1, characterized in that: A hemispherical joint support and a hemispherical joint are also provided between the sensor and the nut; The lower end surface of the hemispherical joint support contacts the upper end surface of the sensor, the hemispherical surface of the hemispherical joint is installed in the hemispherical joint support, and the lower end surface of the nut contacts the upper end surface of the hemispherical joint.

3. The non-torsion preload loading device according to claim 1, characterized in that: A large gasket is installed between the thrust bearing and the sensor; The lower end surface of the large gasket contacts the upper end surface of the fixed ring of the thrust bearing, and the lower end surface of the sensor contacts the upper end surface of the large gasket.

4. The non-torsion preload loading device according to claim 1, characterized in that: Holes perpendicular to the central axis of the inner support frame are respectively opened on both sides of the closed end of the inner support frame, and the two holes are 180 degrees apart on the circumference; A loading arm is mounted in each hole; The external threads on the inner support frame and the internal threads on the outer support frame are both fine pitch threads; The sensor is an annular pressure sensor.

5. A non-torsion preload method, characterized in that: The method comprises: Step 1: Obtain the tension F on the top rod of the clamped device A and the strain value of the push rod ε A the relationship between; Step 2: Obtain the reading F of the sensor on the non-torsion preload loading device as described in any one of claims 1 to 4 c and the strain value of the top rod ε c the relationship between; Step 3: The tension F of the top rod obtained in step 1 A and the strain value of the push rod ε A The relationship between and the sensor reading F obtained in step 2 c and the strain value of the push rod ε c The relationship between the sensor and the c The tension F on the top rod A the relationship between; Step 4: According to the designed preload, use the sensor reading F obtained in step 3 c The tension F on the top rod A The relationship between the sensor is used to determine the indication of the sensor, and then the non-torsion preload loading device as described in any one of claims 1 to 4 is used to achieve the compression of the compressed device.

6. The non-torsion preload loading method according to claim 5, characterized in that: The operation of step one includes: Step 101: Take out the push rod of the pressing device, and stick two groups of strain gauges on the push rod, each group of strain gauges includes two strain gauges, the centers of the two strain gauges in each group are located in the same plane perpendicular to the central axis of the push rod, and the centers of the two strain gauges in each group are 180 degrees apart on the circumference; the line connecting the centers of the two strain gauges in the first group is perpendicular to the line connecting the centers of the two strain gauges in the second group; Step 102: Install the clamping rod on the universal material testing machine, load it step by step from 0N to 500N, then unload it step by step from 500N to 0N, record the strain value of each strain gauge after each level of loading and calculate the sum of the strain values ​​of each group of strain gauges, record the strain value of each strain gauge after each level of unloading and calculate the sum of the strain values ​​of each group of strain gauges, and then perform the following operations: If the sum of the strain values ​​of the two groups of strain gauges is not equal at least once or the strain value of at least one strain gauge is not 0 when unloaded to 0N, it is determined to be abnormal, and the pasting position of the strain gauge is adjusted at this time, and the process returns to step 102; If the sum of the strain values ​​of the two groups of strain gauges is equal, and the strain values ​​of each strain gauge are all 0 when unloading to 0N, the preloading is completed and the process goes to step 103; Step 103: Perform formal loading: Use gradient loading method to obtain different tensile forces F A The corresponding strain value ε A , and then the tension F on the top rod is obtained by least squares fitting A and the strain value of the top rod ε A The relationship between: F A =f(ε A ).

7. The non-torsion preload loading method according to claim 5, characterized in that: The operation of step 2 includes: Step 201: remove the ejector rod in the clamped device from the universal material testing machine and install it into the clamped device; Step 202: Install the non-torsion preload loading device as described in any one of claims 1 to 4 on the device to be pressed; set the initial preload force F B Equal to the design preload F 设计 ; Step 203: Determine the preload force F B Is it greater than F? 设计 +1000, if yes, then go to step 204, if no, then rotate the loading arm lever in the reverse direction to return the loading device to the unloaded state, and then rotate the loading arm lever forward to make the sensor reading reach F B , then tighten the lock nut to reduce the sensor reading to F B - Set the value and record the sensor reading F at this time c and strain value ε c , then calculate F B =F B +P, return to step 203; Step 204: Obtain the sensor reading F by least squares fitting c and the strain value of the top rod ε c The relationship between: F c =f(ε c ).

8. The non-torsion preload loading method according to claim 5, characterized in that: The operation of step three includes: Step 301: Based on F A =f(ε A ) and F c =f(ε c ) relationship, and obtain the relationship between the sensor reading and the tension on the push rod: F A =f(F c ); Step 302: F 设计 As F A Substitute F A =f(F c ) to obtain the corresponding sensor reading F c , the sensor reading F c As the applied force F 施加 .

9. The non-torsion preload loading method according to claim 5, characterized in that: The operation of step 4 includes: Step 401: installing the non-torsion preload loading device as described in any one of claims 1 to 4 on the pressed device; Step 402: Rotate the loading arm to lift the inner support frame and stretch the ejector rod; Step 403: When the sensor reading is (F 施加 +100)N, stop rotating the loading arm; Step 404: Tighten the locking nut. When the sensor indicates F 施加 Stop tightening the lock nut; Step 405: Rotate the loading arm in the opposite direction, and stop rotating when the sensor reading is less than 50N; at this time, loosen the locking rod, separate the locking rod from the top rod, and remove the non-torsion preload loading device as described in any one of claims 1-4.

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