A cantilevered plate reciprocating bending fatigue testing machine and its working method

Abstract

The present application relates to a kind of cantilever flat plate reciprocating bending fatigue testing machine and its working method, including rack, heating system is arranged on the top plate of the rack, the inside of the heating system is provided with the fixed end of the fixed component for fixing the horizontally arranged flat plate sample, the right side of the fixed component is provided with the loading component for being connected with the free end of flat plate sample;Power component is arranged on the bottom plate of the rack, the power output end of the power component is connected with loading component via the vertically reciprocating movable conjugate transmission component, power component drives loading component up and down swing, realizes the reciprocating bending of flat plate sample.The present application is reasonable in design, can be carried out in high temperature environment flat plate sample reciprocating bending fatigue test, it is helpful to the fatigue life research of material in high temperature environment, and high reliability, loading accurate and low cost.

Description

Technical field:

[0002] The invention relates to a cantilever type flat plate reciprocating bending fatigue testing machine and a working method thereof. Background technology:

[0004] Fatigue failure of components can affect production efficiency and thus the economy, and more seriously, endanger workers' lives. To prevent fatigue failure, it is necessary to explore the fatigue life of materials. The current method is to conduct fatigue tests, and the equipment used for fatigue testing is a fatigue testing machine.

[0005] Currently, the most common fatigue testing machine is the bending fatigue testing machine, which is often used for fatigue testing of rod-shaped specimens. Few fatigue testing machines are suitable for bending fatigue testing of flat specimens. In the prior art, Chinese Patent No. 201110124491.7 discloses a reciprocating bending corrosion fatigue testing machine. This testing machine is equipped with multiple eccentric wheel mechanisms on the rotating shaft, which immerses all specimens in a corrosion tank filled with a corrosive medium, enabling simultaneous testing of multiple flat specimens in a corrosive environment. Chinese Patent No. 201820391665.3 discloses a repeated bending fatigue testing device for metal sheets. The loading mechanism of this device uses a crank-slider mechanism to perform fatigue testing on the metal sheet by reciprocating bending in the forward and backward directions. This mechanical structure only allows loading of one specimen at a time. Chinese Patent No. 201921169211.2 discloses a bending fatigue testing device for flat specimens based on a vibration table. This device uses a vibration table as its loading mechanism, which significantly improves testing efficiency. However, these aforementioned flat plate reciprocating bending fatigue testing machines cannot perform fatigue testing in high-temperature environments. Therefore, it is necessary to propose a cantilevered plate reciprocating bending fatigue testing machine. Summary of the invention:

[0007] The present invention aims to improve the problems existing in the above-mentioned prior art. That is, the technical problem to be solved by the present invention is to provide a cantilevered plate reciprocating bending fatigue testing machine and a working method thereof.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a cantilevered flat plate reciprocating bending fatigue testing machine, comprising a frame, a heating system is provided on the top plate of the frame, a fixing assembly for fixing the fixed end of a horizontally arranged flat plate specimen is provided inside the heating system, and a loading assembly for connecting with the free end of the flat plate specimen is provided on the right side of the fixing assembly; a power assembly is provided on the bottom plate of the frame, the power output end of the power assembly is connected to the loading assembly via a conjugate transmission assembly that can move back and forth vertically, and the power assembly drives the loading assembly to swing up and down through the conjugate transmission assembly to realize reciprocating bending of the flat plate specimen.

[0009] Further, the conjugate transmission assembly comprises a yoke block, an eccentric spline shaft, an inner eccentric wheel, an outer eccentric wheel and a bearing, the yoke block is vertically arranged, the middle part of the yoke block is provided with a stepped through hole penetrating in the transverse direction, and the eccentric spline shaft is arranged in the transverse direction and the spline part extends into the stepped through hole; the inner eccentric wheel is provided with a spline hole matched with the spline part of the eccentric spline shaft, and the outer periphery of the left end of the inner eccentric wheel is provided with a limiting flange; the outer eccentric wheel is sleeved on the outer side of the inner eccentric wheel, the right end surface of the outer eccentric wheel is connected with the middle part of the right end surface of the spline part of the eccentric spline shaft through a connecting gasket; and the bearing is sleeved on the left outer side of the outer eccentric wheel, and is located between the limiting flange and the stepped surface of the stepped through hole and is in sliding fit with the left end of the stepped through hole.

[0010] Further, the right end surface of the outer eccentric wheel is provided with a first connecting hole near the edge part, the middle part of the right end surface of the spline part of the eccentric spline shaft is provided with a second connecting hole, and the two ends of the connecting gasket are fixed through the locking bolts matched with the first connecting hole and the second connecting hole.

[0011] Further, the middle part of the top surface of the yoke block is screwed with a vertically arranged upper shaft, the upper end of the upper shaft is connected with the loading assembly through a rod end joint bearing; the middle part of the bottom surface of the yoke block is screwed with a vertically arranged lower shaft, and the lower shaft is in sliding fit with the linear bearing of the circular flange arranged at the right end of the bottom plate of the rack.

[0012] Further, the loading assembly comprises a pair of horizontally arranged Z-shaped swing rods symmetrically distributed in the front and rear directions, the right ends of the swing rods are connected through a joint, the right end of the joint is hinged with the upper end of the rod end joint bearing, the left ends of the swing rods are hinged with the hinge seats fixed on the top plate through longitudinal hinge shafts, and the left end bottoms of the swing rods are fixed with a longitudinally arranged loading plate, and the free end of the flat specimen is locked on the top surface of the loading plate.

[0013] Further, the left end bottoms of the swing rods are provided with a plurality of first locking holes for locking the loading plate in cooperation with the first bolts and are uniformly distributed in the transverse direction; and the left end of the top plate is provided with a plurality of second locking holes for locking the adjusting frame in cooperation with the second bolts and are uniformly distributed in the transverse direction.

[0014] Further, the power assembly comprises a power motor, the output shaft of the power motor is connected with the input shaft of the power head through a shaft coupling, and the output shaft of the power head is the eccentric spline shaft; the left end of the bottom plate is fixed with a motor seat, and the power motor is installed on the top of the motor seat.

[0015] Further, the detection device includes a proximity switch, an electronic counter and an automatic control relay, the proximity switch is installed on the top surface of the motor base right end and is located below the protruding bolt of the shaft coupling, the proximity switch detects the output high potential signal to the electronic counter after the shaft coupling rotates one circle; the common signal line and the low signal line of the automatic control relay are connected in parallel on the support plate, the high signal line of the automatic control relay is installed on the loading plate, when the automatic control relay detects that the common parallel line and the high line are disconnected, the counting channel of the proximity switch is cut off.

[0016] Further, the heating system includes a heating furnace which is arranged outside the fixed assembly and the heating assembly, the bottom of the heating furnace is supported by the bracket fixed on the top plate, the bottom of the heating furnace is provided with a gap hole for the upper end of the conjugate transmission assembly to pass through, the heating furnace is provided with an internal circulation cooling assembly, and the heating furnace is connected with the temperature control box.

[0017] Another technical scheme of the present application is a working method of the cantilever type flat plate reciprocating bending fatigue testing machine, and the working method comprises the following steps: fixing the free end of the flat plate sample to the loading plate, fixing the fixed end of the flat plate sample to the support plate, then adjusting the heating temperature of the heating furnace, starting the power motor, converting the rotary motion of the power motor into the up-down reciprocating linear motion of the conjugate transmission assembly, driving the loading assembly to swing up and down by the conjugate transmission assembly, and driving the flat plate sample to bend up and down by the loading assembly; when the flat plate sample is broken, the automatic control relay detects that the common parallel line and the high line are disconnected, the counting channel of the proximity switch is cut off, the electronic counter cannot receive the proximity switch signal, and the counting is stopped and the current recorded value is kept.

[0018] Compared with the prior art, the present application has the following effects: the present application has reasonable design, can realize the reciprocating bending fatigue test of the flat plate sample in a high temperature environment, is helpful for the material fatigue life research in a high temperature environment, and has high reliability, accurate loading and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a three-dimensional structure schematic diagram of the embodiment of the present application;

[0021] Figure 2 is a front view structure schematic diagram of the embodiment of the present application;

[0022] Figure 3 is Figure 2 omits the structure schematic diagram of the heating system;

[0023] Figure 4 is a top view structure schematic diagram of the embodiment of the present application (omits the heating system);

[0024] Figure 5 isFigure 4 A-A cross-sectional view in the figure;

[0025] Figure 6 is a cross-sectional structure schematic diagram of the conjugate transmission assembly in the embodiment of the present application;

[0026] Figure 7 is a three-dimensional structure schematic diagram of the yoke block in the embodiment of the present application;

[0027] Figure 8 is an eccentricity adjustment schematic diagram in the embodiment of the present application Figure 1 ;

[0028] Figure 9 is an eccentricity adjustment schematic diagram in the embodiment of the present application Figure 2 ;

[0029] Figure 10 is a working principle diagram of the embodiment of the present application;

[0030] Figure 11 is a structure schematic diagram of the flat specimen in the embodiment of the present application;

[0031] Figure 12 is a principle diagram of the repeated bending fatigue test of the flat specimen in the embodiment of the present application;

[0032] Figure 13 is a stress distribution finite element numerical simulation result of the flat specimen in the embodiment of the present application when the amplitude is maximum.

[0033] In the figure:

[0034] 1-horizontal adjustment support type caster; 2-bottom plate; 3-motor base; 4-power motor; 5-proximity switch; 6-coupling; 7-top plate; 8-heating furnace; 81-bracket, 9-power head; 91-eccentric key shaft; 10-conjugate transmission assembly; 101-inner eccentric wheel; 1011-limit flange; 102-outer eccentric wheel; 103-bearing; 104-upper shaft; 105-yoke block; 106-connection gasket; 107-lower shaft; 11-adjustment frame; 12-supporting plate; 130-first high-temperature-resistant nylon pad; 131-second high-temperature-resistant nylon pad; 132-third high-temperature-resistant nylon gasket; 133-high-temperature-resistant nylon sleeve; 14-hinge base; 15-loading plate; 16-rocker; 17-joint; 18-rod end joint bearing, 19-flat specimen; 20-stepped through hole; 21-first connecting hole; 22-second connecting hole; 23-first locking hole; 24-second locking hole; 25-rack; 26-vertical support rod; 27-circular flange linear bearing. DETAILED DESCRIPTION:

[0036] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0037] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] like Figures 1-9 As shown, the present invention provides a cantilevered flat plate reciprocating bending fatigue testing machine, comprising a frame 25. A heating system is provided on the top plate 7 of the frame 25. A fixing assembly is provided within the heating system for fixing the fixed end of a horizontally arranged flat plate specimen. A loading assembly is provided on the right side of the fixing assembly for connecting to the free end of the flat plate specimen 19. A power assembly is provided on the bottom plate 2 of the frame 25. The power output end of the power assembly is connected to the loading assembly via a conjugate transmission assembly 10 that can move back and forth vertically. The power assembly drives the loading assembly to swing up and down through the conjugate transmission assembly, thereby achieving reciprocating bending of the flat plate specimen 19. The flat plate specimens mounted on the fixing assembly and the loading assembly are heated by the heating system. The loading assembly swings up and down driven by the conjugate transmission assembly, and the loading assembly drives the flat plate specimen to bend reciprocally up and down, thereby achieving reciprocating bending fatigue testing of the flat plate specimens in a high-temperature environment, which is beneficial to the study of material fatigue life in high-temperature environments.

[0039] In this embodiment, the frame 25 includes a top plate 7 and a bottom plate 2 that are distributed parallel to each other. The top plate 7 and the bottom plate 2 are connected on all sides via vertical support rods 26. Horizontally adjustable support casters 1 are provided around the bottom of the bottom plate 2 for horizontal adjustment and movement of the entire testing machine.

[0040] In this embodiment, the conjugate transmission assembly 10 includes a yoke 105, an eccentric spline shaft 91, an inner eccentric wheel 101, an outer eccentric wheel 102 and a bearing 103. The yoke 105 is vertically arranged, and a stepped through hole 20 is provided in the middle of the yoke 105 and passes through in the horizontal direction. The left end of the stepped through hole 20 has a large aperture and the right end has a small aperture; the eccentric spline shaft 91 is arranged horizontally, and the spline portion of the eccentric spline shaft 91 extends into the stepped through hole 20; the inner eccentric wheel 101 extends into the stepped through hole 20, and a spline hole is provided on the inner eccentric wheel 101 that matches the spline portion of the eccentric spline shaft 91. The outer periphery of the left end of the inner eccentric wheel 101 A limiting flange 1011 is provided on the side; the outer eccentric wheel 102 extends into the stepped through hole 20, and the outer eccentric wheel 102 is sleeved on the outside of the inner eccentric wheel 101. The right end face of the outer eccentric wheel 102 is connected to the middle part of the right end face of the spline part of the eccentric spline shaft 91 through a connecting gasket 106, so that the eccentric spline shaft 91, the inner eccentric wheel 101 and the outer eccentric wheel 102 are connected into a whole, and the three rotate together; the bearing 103 is sleeved on the outside of the left end of the outer eccentric wheel 102, and the bearing 103 is located between the limiting flange 1011 and the stepped surface of the stepped through hole 20, and the bearing 103 is slidably fitted with the left end of the stepped through hole 20. As the eccentric spline shaft 91 rotates, the bearing 103 mounted on the outer eccentric 102 slides within the left end of the stepped through hole 20 in the yoke 105, causing the yoke 105 to move up and down, thereby achieving reciprocating linear motion. Preferably, the bearing 103 is a deep groove ball bearing. The eccentric spline shaft and the inner and outer eccentric structures achieve reciprocating bending motions of varying amplitudes.

[0041] It should be noted that the eccentric spline shaft has an eccentrically arranged spline portion, the inner eccentric wheel is eccentrically arranged relative to the spline portion, and the outer eccentric wheel is eccentrically arranged relative to the inner eccentric wheel.

[0042] In this embodiment, a first connecting hole 21 is defined on the right end surface of the outer eccentric 102 near the edge, and a second connecting hole 22 is defined in the middle of the right end surface of the spline portion of the eccentric spline shaft 91. The ends of the connecting gasket 106 are secured by locking bolts that engage with the first connecting hole 21 and the second connecting hole 22, respectively. It should be noted that when adjusting the positional relationship between the inner and outer eccentrics and the eccentric spline shaft according to the desired test amplitude, it is necessary to replace the connecting gaskets with different spacings between the first and second connecting holes to accommodate the desired amplitude.

[0043] In this embodiment, the shape of the flat plate specimen 19 is a variable cross-section type in order to achieve the requirement of constant stress, and the flat plate specimen 19 is loaded in a cantilever manner.

[0044] In the embodiment, the loading assembly comprises a pair of Z-shaped swing rods 16 arranged horizontally and symmetrically distributed along the front and rear directions, the distance between the left ends of the swing rods is large, and the distance between the right ends of the swing rods is small; the right ends of the pair of swing rods 16 are connected through a joint 17, the joint 17 can be hinged with the right ends of the pair of swing rods, the right end of the joint 17 is hinged with the upper end of the rod end joint bearing 18; the left ends of the pair of swing rods 16 are respectively hinged with the hinge seats 14 fixed on the top plate 7 through longitudinal hinge shafts, so as to facilitate the up and down swinging of the pair of swing rods 16, the bottom between the left ends of the pair of swing rods 16 is fixed with a longitudinally arranged loading plate 15, and the free end of the flat plate sample 19 is locked on the top surface of the loading plate 15 through bolts.

[0045] In the embodiment, the fixing assembly comprises an adjusting frame 11 vertically fixed on the top surface of the top plate 7, and the top of the adjusting frame 11 is fixed with a longitudinally arranged support plate 12, and the fixed end of the flat plate sample 19 is locked on the top surface of the support plate 12 through bolts.

[0046] In the embodiment, the left end of the pair of swing rods 16 is provided with a plurality of first locking holes 23 arranged along the transverse direction, and the first locking holes 23 are used for locking the loading plate 15 with the first bolts; the left end of the top plate 7 is provided with a plurality of second locking holes 24 arranged along the transverse direction, and the second locking holes 24 are used for locking the adjusting frame 11 with the second bolts. Through the plurality of first locking holes and the plurality of second locking holes, the fixed positions of the loading plate and the adjusting frame can be adjusted along the transverse direction, so as to meet the test requirements of flat plate samples of different lengths.

[0047] In the embodiment, the first high-temperature-resistant nylon pad 130 is arranged between the support plate 12 and the adjusting frame 11, the second high-temperature-resistant nylon pad 131 is arranged at the contact part of the loading plate 15 and the swing rod 16, and the third high-temperature-resistant nylon pad 132 and the high-temperature-resistant nylon sleeve 133 are arranged at the bolt part, so as to achieve insulation.

[0048] In the embodiment, the heating system comprises a heating furnace 8 covering the outside of the fixing assembly and the heating assembly, the bottom of the heating furnace 8 is supported by the support 81 fixed on the top plate 7, the bottom of the heating furnace 8 is provided with a gap hole for facilitating the passing of the upper end of the conjugate transmission assembly, the heating furnace 8 is provided with an internal circulation cooling assembly, and the heating furnace is connected with a temperature control box, so as to meet the test requirements in different temperature environments.

[0049] In the embodiment, the power assembly comprises a power motor 4, the output shaft of the power motor 4 is connected with the input shaft of the power head 9 through the shaft coupling 6, and the output shaft of the power head 9 is an eccentric spline shaft 91; the left end of the bottom plate 2 is fixed with a motor seat 3, and the power motor 4 is installed on the top of the motor seat 3. Further, the power motor is connected with a frequency converter, so as to facilitate the adjustment of the experimental frequency.

[0050] Another embodiment, the frequency converter is also connected with the alarm module, when the power supply voltage of the device is insufficient, the frequency converter detects the power supply voltage required by the power motor 4, the frequency converter will not run to protect the power motor 4, and the alarm provides fault information. When the device starts, the device does not respond and does not run, that is, the power motor 4 is in a fault state or a state that cannot be started. The frequency converter detects whether the power motor is in a normal state. When the power motor 4 is in a starting operation state, the frequency converter will synchronously detect the state of the power motor. If the power motor fails, the frequency converter will stop the operation of the power motor 4 to achieve the purpose of protecting the power motor 4. The power motor 4 fault is detected by the frequency converter and the fault information of the power motor 4 is displayed. The maintenance personnel will repair the power motor 4 according to the fault information detected by the frequency converter.

[0051] Another embodiment, the detection device also includes a proximity switch 5, an electronic counter and an automatic control relay. The proximity switch 5 is installed at the top right end of the motor base 3 and located below the protruding bolt of the shaft coupling 6. The proximity switch 5 detects the high potential signal output to the electronic counter after the shaft coupling 6 rotates one circle. When the power motor 4 rotates, it drives the shaft coupling 6 to rotate. When the shaft coupling 6 rotates one circle, the protruding bolt on the shaft coupling 6 passes through the proximity switch 5, and the proximity switch 5 outputs a high potential signal to the electronic counter. When the electronic counter receives the high potential signal output by the proximity switch 5, it will count once.

[0052] The common signal line of the automatic control relay is parallelly connected with the low signal line on the support plate, and the high signal line of the automatic control relay is connected on the loading plate. When the automatic control relay detects that the common parallel line and the high line are disconnected, it cuts off the counting channel of the proximity switch. Because the counting channel is cut off, the electronic counter cannot accept the proximity switch 5 signal and will stop counting and keep the current recorded value. At the same time, the automatic control relay is also connected with the PLC and the alarm module. When the detection signal is cut off, the automatic control relay outputs a potential signal to the PLC. The PLC receives the output signal of the automatic control relay, enters the internal counting stop program, and sends a work position completion instruction. The power motor 4 stops rotating and sends the instruction to the external control circuit relay. At this time, the external relay is turned on, controls the alarm module to start, and prompts the operator that the work position has completed the experiment.

[0053] In this embodiment, the eccentricity of the eccentric spline shaft 91 is 9mm, the eccentricity of the inner eccentric wheel 101 is 4.4mm, and the eccentricity of the outer eccentric wheel 102 is 2mm. Markings are engraved on the end faces of the eccentric spline shaft 91, the inner eccentric wheel 101 and the outer eccentric wheel 102, which are convenient for test personnel to adjust the amplitude. The eccentricity and the amplitude form a similar triangle, and the formula is:

[0054]

[0055] Wherein s is the amplitude of the test piece; e is the eccentricity; l is the distance from the free end of the flat test piece to the center of the hinged seat, under the shape and size of the test piece, l = 55 mm; L is the center distance of the two holes of the rod piece, L = 140 mm.

[0056] In the embodiment, the upper shaft 104 vertically arranged in the middle of the top surface of the yoke block 105 is screwed, the upper end of the upper shaft 104 is connected with the loading assembly through the rod end joint bearing 18, and the upper shaft 104 moves up and down to drive the loading assembly to act through the rod end joint bearing 18; the lower shaft 107 vertically arranged in the middle of the bottom surface of the yoke block 105 is screwed, and the lower shaft 107 is in sliding fit with the circular flange linear bearing arranged at the right end of the bottom plate 2 of the rack to play a guiding role.

[0057] In the embodiment, when the end surface axis line of the inner eccentric wheel 101 and the outer eccentric wheel 102 is 180° relative to the horizontal plane, the angle a between the end surface axis of the eccentric spline part 91 and the end surface axis of the outer eccentric wheel 102 is adjusted, and the eccentricity and amplitude in the following table can be realized. At this time, the two holes on the connecting gasket 106 correspond to the first connecting hole (located on the outer eccentric wheel 102) and the second connecting hole position (located on the eccentric spline shaft 91), and the hole distance of the two holes is 21.6 mm.

[0058]

[0059] In the embodiment, when the end surface axis line of the inner eccentric wheel 101 and the outer eccentric wheel 102 is 0° relative to the horizontal plane, the angle a between the end surface axis of the eccentric spline part 91 and the end surface axis of the outer eccentric wheel 102 is adjusted, and the eccentricity and amplitude in the following table can be realized. At this time, the two holes on the connecting gasket 106 correspond to the first connecting hole (located on the outer eccentric wheel 102) and the second connecting hole position (located on the eccentric spline shaft 91), and the hole distance of the two holes is 30.4 mm.

[0060]

[0061] The working method of the cantilever type flat plate reciprocating bending fatigue testing machine in the embodiment is as follows: firstly, the positional relationship between the inner and outer eccentric wheels and the eccentric spline shaft 91 is adjusted according to the required amplitude of the test; then, the free end of the flat plate sample 19 is fixed to the loading plate 15, the fixed end of the flat plate sample 19 is fixed to the support plate 12, the temperature control box is opened, the heating temperature of the heating furnace 8 is adjusted, the power motor 4 is started, the rotary motion of the power motor 4 is converted into the up-down reciprocating linear motion of the conjugate transmission assembly 10, the conjugate transmission assembly 10 drives the loading assembly to swing up and down, and the loading assembly drives the flat plate sample 19 to reciprocate up and down; when the flat plate sample 19 breaks, the automatic control relay detects that the common parallel line is disconnected from the high line, the counting channel of the proximity switch is cut off, and since the counting channel is cut off, the electronic counter cannot receive the proximity switch signal, so the counting is stopped and the current recorded value is kept. After the flat plate reciprocating bending fatigue test is stopped, the flat plate sample is taken down after cooling, and the data on the electronic counter is recorded.

[0062] The present application has the following advantages:

[0063] 1. The structure for adjusting the amplitude is special, the eccentric spline shaft-inner and outer eccentric wheel structure is adopted to adjust the amplitude of the flat plate sample, the rotary motion is converted into the up-down reciprocating motion of the upper shaft through the conjugate structure, and then the free end of the flat plate sample is loaded, so that the reliability is good.

[0064] 2. The bending fatigue test of flat plate samples of different lengths can be met, the test requirements of flat plate samples of different lengths are met by adjusting the different positions of the adjusting frame on the top plate or adjusting the position of the loading plate on the swing rod, and the use flexibility is improved.

[0065] 3. The heating system is installed, the flat plate reciprocating bending fatigue test at different temperatures can be realized, and the fatigue life research of materials in a high-temperature environment is helpful.

[0066] If the present application discloses or involves mutually fixedly connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachably fixed connection (for example, connected by using bolts or screws), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, manufactured by using a casting process to form integrally) (obviously, except for the integral forming process).

[0067] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the present application include states or shapes similar, similar or close to them, unless otherwise stated.

[0068] Any of the components provided herein can be assembled components or unitary components manufactured by an integral molding process.

[0069] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent replacements; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application claimed.

Claims

1. A cantilevered plate reciprocating bending fatigue testing machine, characterized in that: The machine comprises a frame, a heating system is provided on the top plate of the frame, a fixing assembly is provided inside the heating system for fixing the fixed end of a horizontally arranged flat sample, and a loading assembly is provided on the right side of the fixing assembly for connecting with the free end of the flat sample; a power assembly is provided on the bottom plate of the frame, a power output end of the power assembly is connected to the loading assembly via a conjugate transmission assembly that can move back and forth vertically, and the power assembly drives the loading assembly to swing up and down through the conjugate transmission assembly to achieve reciprocating bending of the flat sample; The conjugate transmission assembly includes a yoke, an eccentric spline shaft, an inner eccentric wheel, an outer eccentric wheel and a bearing, the yoke is arranged vertically, and a stepped through hole is provided in the middle part of the yoke which penetrates horizontally, the eccentric spline shaft is arranged horizontally and the spline portion extends into the stepped through hole; the inner eccentric wheel is provided with a spline hole which matches the spline portion of the eccentric spline shaft, and a limiting flange is provided on the outer peripheral side of the left end of the inner eccentric wheel; the outer eccentric wheel is sleeved on the outer side of the inner eccentric wheel, and the right end face of the outer eccentric wheel is connected to the middle part of the right end face of the spline portion of the eccentric spline shaft through a connecting gasket; the bearing is sleeved on the outer side of the left end of the outer eccentric wheel, and the bearing is located between the limiting flange and the stepped surface of the stepped through hole and slides with the left end of the stepped through hole; A first connecting hole is formed on the right end surface of the outer eccentric wheel near the edge, and a second connecting hole is formed in the middle of the right end surface of the spline portion of the eccentric spline shaft. Both ends of the connecting gasket are fixed by locking bolts respectively matched with the first connecting hole and the second connecting hole. A vertically arranged upper shaft is screwed to the middle of the top surface of the yoke, and the upper end of the upper shaft is connected to the loading assembly through a rod end joint bearing; a vertically arranged lower shaft is screwed to the middle of the bottom surface of the yoke, and the lower shaft is slidably engaged with a round flange linear bearing arranged at the right end of the bottom plate of the frame; The loading assembly includes a pair of Z-shaped rocker arms that are horizontally arranged and symmetrically spaced along the front and rear directions. The right ends of the pair of rocker arms are connected by a joint, and the right end of the joint is hinged to the upper end of the rod-end joint bearing; the left ends of the pair of rocker arms are respectively hinged to the hinge seats fixed on the top plate through longitudinal hinge shafts, and a longitudinally arranged loading plate is fixed between the bottoms of the left ends of the pair of rocker arms, and the free end of the flat specimen is locked to the top surface of the loading plate; the fixing assembly includes an adjustment frame fixed to the top surface of the top plate, a longitudinally arranged support plate is fixed to the top of the adjustment frame, and the fixed end of the flat specimen is locked to the top surface of the support plate; The bottom of the left end of the pair of swing arms is provided with a plurality of first locking holes evenly spaced in the transverse direction and used to cooperate with the first bolt to lock the loading plate; the left end of the top plate is provided with a plurality of second locking holes evenly spaced in the transverse direction and used to cooperate with the second bolt to lock the adjustment frame; The power assembly includes a power motor, the output shaft of which is connected to the input shaft of the power head via a coupling, and the output shaft of the power head is an eccentric spline shaft; a motor seat is fixed to the left end of the base plate, and the power motor is installed on the top of the motor seat; It also includes a detection device, which includes a proximity switch, an electronic counter and an automatic control relay. The proximity switch is installed at the right end of the top surface of the motor base and is located directly below the protruding bolt position of the coupling. After the proximity switch detects that the coupling rotates one circle, it outputs a high-potential signal to the electronic counter; the common signal line and the low-level signal line of the automatic control relay are installed in parallel on the support plate, and the high-level signal line of the automatic control relay is installed on the loading plate. When the automatic control relay detects that the common parallel line is disconnected from the high-level line, the counting channel of the proximity switch is cut off.

2. The cantilevered plate reciprocating bending fatigue testing machine according to claim 1, characterized in that: The heating system includes a heating furnace covered on the outside of the fixed component and the heating component. The bottom of the heating furnace is supported by a bracket fixed on the top plate. The bottom of the heating furnace is provided with a makeshift hole to facilitate the passage of the upper end of the conjugate transmission component. The heating furnace is provided with an internal circulation cooling component, and the heating furnace is connected to the temperature control box.

3. A method for operating a cantilevered plate reciprocating bending fatigue testing machine, characterized in that: The invention comprises the use of the cantilevered flat plate reciprocating bending fatigue testing machine as described in claim 2, wherein during operation: first, the positional relationship between the inner and outer eccentric wheels and the eccentric spline shaft is adjusted according to the amplitude required for the test; the free end of the flat plate specimen is fixed to the loading plate, and the fixed end of the flat plate specimen is fixed to the support plate; then, the heating temperature of the heating furnace is adjusted, and the power motor is started, and the rotational motion of the power motor is converted into the up and down reciprocating linear motion of the conjugate transmission component, the conjugate transmission component drives the loading component to swing up and down, and the loading component drives the flat plate specimen to bend up and down; when the flat plate specimen breaks, the automatic control relay detects that the common parallel line is disconnected from the high-level line, and will cut off the counting channel of the proximity switch. Since the counting channel is cut off, the electronic counter cannot receive the proximity switch signal and will stop counting and maintain the currently recorded value.

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