CN116519328A - Device and method for testing fatigue reliability of weight-related parts for loader - Google Patents
Device and method for testing fatigue reliability of weight-related parts for loader Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 80
- 238000000034 method Methods 0.000 title claims description 44
- 238000011068 loading method Methods 0.000 claims abstract description 69
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- 238000001228 spectrum Methods 0.000 claims description 38
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- 238000006073 displacement reaction Methods 0.000 claims description 14
- 229910000831 Steel Inorganic materials 0.000 claims description 12
- 239000010959 steel Substances 0.000 claims description 12
- 238000012545 processing Methods 0.000 claims description 6
- 239000010720 hydraulic oil Substances 0.000 claims description 5
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- 238000012935 Averaging Methods 0.000 claims description 3
- 230000001133 acceleration Effects 0.000 claims description 3
- 239000003921 oil Substances 0.000 claims description 3
- 238000009661 fatigue test Methods 0.000 abstract description 15
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- 238000004364 calculation method Methods 0.000 description 3
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
- G01M17/007—Wheeled or endless-tracked vehicles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M13/00—Testing of machine parts
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention discloses a fatigue reliability test device and a loading method for a weight-closing part for a loader, wherein the fatigue reliability test device comprises a front frame support, a rear frame support, an actuator and a rigid wall; the front frame support is used for supporting the front frame and enabling the front frame to follow when the loader acts; the rear frame support is used for supporting the rear frame; one end of the actuator is adjustably mounted on the rigid wall, and the other end of the actuator is connected with the loader bucket. The fatigue reliability test device for the weight-closing part for the loader is applicable to fatigue tests of working devices of loaders of different types, and the structural spacing of the weight-closing part is adjustable. According to the fatigue reliability test loading method for the working device of the loader, the force sensor is used for acquiring the hinge point force, and the obtained time course of the loading force of the actuator is consistent with that of actual damage, so that the loading in a laboratory is facilitated.
Description
Technical Field
The invention relates to a fatigue reliability test device and a loading method for a weight-related part for a loader, and belongs to the technical field of fatigue tests.
Background
The front frame of the loader is used as a basic structure for supporting the working device and bears the combined action of tension and compression, bending and impact loads from all directions. At present, the fatigue test devices for the working devices of the loader are more, and the fatigue test devices and the loading method which are specially used for the front frame of the loader are few, and the hinge point of the front frame is rigidly fixed when the fatigue test of the working devices is carried out, so that the stress and the movement modes of the front frame are greatly different from the actual working states, and therefore, the fatigue test of the front frame can not be completed when the fatigue test is carried out on the working devices.
The existing loader test load spectrum processing technology generally draws a test spectrum according to the equivalent relation between the bending moment of the section of the movable arm and the equivalent external force, and the method only carries out equivalent calculation on specific points, so that the method is accurate only on the specific points and has no universality. In addition, the existing processing methods of the test load spectrum have certain errors on the global fatigue evaluation of the structure, or the processed load spectrum is inconvenient for loading in a laboratory. There is therefore a need for improved methods of acquiring and processing loader load spectrum.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides the fatigue reliability test device for the weight-related parts for the loader, which not only can be used for the fatigue test of the front frame of the loader, but also can complete the fatigue test of the front frame of the loader and the working device at one time.
The invention also provides a fatigue reliability test loading method of the weight-related part for the loader, which can facilitate the bench test of sinusoidal loading spectrum blocks, and the obtained loading force time history of the actuator is consistent with the actual damage, so that the loading in a laboratory is facilitated.
In order to achieve the above purpose, the invention adopts a fatigue reliability test device for a weight-closing member for a loader, which comprises a front frame support, a rear frame support, an actuator and a rigid wall;
the two front frame supports are symmetrically arranged, each front frame support comprises a front support body, a front frame connecting plate, a cylinder and V-shaped fixing blocks are arranged on each front support body, the lower two V-shaped fixing blocks are fixed on each front support body, the cylinder is fixed between the lower two V-shaped fixing blocks, the upper two V-shaped fixing blocks are fixed at the bottoms of the front frame connecting plates, the cylinder is in clearance fit with the upper two V-shaped fixing blocks, and the front frame supports are used for supporting the front frame and enabling the front frame to follow up when the loader acts;
the two rear frame supports are symmetrically arranged, each rear frame support comprises a rear support body, a rear frame connecting plate and rectangular connecting square steel are arranged on each rear support body, each rectangular connecting square steel is provided with a rectangular connecting block and a slotted hole matched with the rectangular connecting block in shape, and each rear frame support is used for supporting a rear frame;
one end of the actuator is adjustably mounted on the rigid wall, and the other end of the actuator is connected with the loader bucket.
As an improvement, the actuator comprises a hydraulic cylinder, an actuator fixing seat and a bucket fixing seat;
the two ends of the hydraulic cylinder are respectively connected with the actuator fixing seat and the bucket fixing seat through spherical hinge joints, and the hydraulic cylinder can rotate around the spherical hinge joints.
As an improvement, the actuator fixing seat is arranged on the rigid wall, and a plurality of through holes are formed in the actuator fixing seat.
As an improvement, the rigid wall is provided with a plurality of mounting holes.
As an improvement, a triangular reinforcing plate is arranged between the rear frame connecting plate and the rectangular connecting square steel.
The improved bicycle frame comprises a base, wherein a plurality of T-shaped grooves are formed in the base, and the rigid wall, the front frame support and the rear frame support are movably mounted on the base through bolts.
In addition, the invention also provides a loading method for the fatigue reliability test of the weight-related part for the loader, and the loading device for the fatigue reliability test of the weight-related part for the loader is adopted;
firstly, acquiring data such as tested hinge point force, system pressure, oil cylinder displacement and the like, and processing to obtain a bucket tooth tip load spectrum;
then, calculating root mean square values of the vertical and horizontal loads of the bucket tooth point load spectrum in each shoveling process by extracting the vertical and horizontal loads of the bucket tooth point load spectrum in the shoveling process, and averaging the root mean square values of the vertical and horizontal loads of all shoveling processes to obtain the magnitudes of the vertical loads and the horizontal loads of the bucket tooth point in the shoveling process, so that the loading angle of the test actuator is determined;
and finally, determining an oblique loading load spectrum of the test actuator according to the load in the vertical direction of the load spectrum in the bucket tooth sharp digging process and the loading angle of the test actuator, and further determining a sinusoidal loading spectrum block of the bench test.
As an improvement, determining the hinge point force time histories of the left movable arm and the bucket, the hinge point force time histories of the right movable arm and the bucket under a local coordinate system according to the force sensor data;
determining the displacement time history of the movable arm cylinder and the rocker arm cylinder in the movement process according to the data of the displacement sensor;
determining an included angle between a Y axis of a local coordinate system at a zero moment and a vertical direction, an angle time history of a bucket and the ground and an angle time history of a pull rod and a Y axis of the local coordinate system according to the displacement time history of the movable arm cylinder and the displacement time history of the rocker arm cylinder;
determining the component force time histories of the pull rod force in all directions under the local coordinate system according to the angle time histories of the pull rod and the Y axis of the local coordinate system;
determining the bucket tooth tip load time histories under the local coordinate system according to the hinge point force time histories of the left movable arm and the bucket, the hinge point force time histories of the right movable arm and the bucket and the component force time histories of the pull rod force in all directions under the local coordinate system;
determining the bucket tooth tip load time history in the whole movement process under the global coordinate system according to the bucket tooth tip load time history under the local coordinate system, the angle time history of the bucket and the ground, and the included angle between the Y axis of the zero-moment position local coordinate system and the vertical direction;
extracting the bucket tooth tip load time histories in the shoveling process according to the bucket tooth tip load time histories in the whole motion process under the global coordinate system;
determining a loading angle of the test actuator according to the load time history of the tooth tip of the bucket in the shoveling process;
determining the loading force time history of the test actuator according to the loading time history of the bucket tooth tip in the vertical direction and the loading angle of the test actuator in the shoveling process;
removing singular values from test data to obtain a series of load cycles with different amplitude values and average values, dividing the load amplitude values into spectrums according to multistage unequal intervals, compiling an acceleration spectrum of the structure by utilizing a relative equivalent damage principle, and simulating a real operation load according to the operation characteristics of a loader by adopting a low-high-low loading sequence to obtain test loading spectrum blocks, wherein loading waves are sine waves;
and loading the obtained load spectrum of the test actuator onto the fatigue reliability test device of the weight-related part for the loader through the actuator.
Compared with the prior art, the fatigue reliability test device for the weight-closing part for the loader has the advantages that the front frame support can ensure that the front frame follows when the loader acts, the front frame support and the rear frame support can simulate the supporting effect of tires on the front frame and the rear frame, the loading hydraulic cylinder on the actuator can rotate around the spherical hinge joints distributed at the front end and the rear end of the front frame support and can load the resultant force of the vertical load and the horizontal load born by the actual working device of the loader on the bucket of the loader, the fatigue reliability test device can be used for the fatigue test of the front frame of the loader, the fatigue test of the front frame of the loader and the fatigue test result of the working device can be completed at one time, the fatigue reliability test result of the front frame of the loader and the fatigue reliability test result of the working device of the loader are closer to the actual working result, the test error is reduced, and test support is better provided for the fatigue reliability simulation of the weight-closing part of the loader. The fatigue reliability test device for the weight-closing part for the loader is applicable to fatigue tests of working devices of loaders of different types, and the structural spacing of the weight-closing part is adjustable.
According to the fatigue reliability test loading method for the working device of the loader, the force sensor is used for acquiring the hinging point force, the loading angle of the test actuator is determined according to the loading time history of the bucket tooth tip in the shoveling process, and the loading time history of the actuator is determined according to the loading time history of the bucket tooth tip in the vertical direction and the loading angle of the test actuator in the shoveling process.
Drawings
FIG. 1 is a schematic view of a structure of a load lock fatigue reliability test apparatus for a loader according to the present invention;
FIG. 2 is a schematic view of the structure of the front frame support in the load lock weight fatigue reliability test apparatus of the present invention;
FIG. 3 is a schematic view of the structure of the rear frame support in the load lock weight fatigue reliability test apparatus of the present invention;
FIG. 4 is a schematic view of the structure of an actuator in the load lock fatigue reliability test device according to the present invention;
FIG. 5 is a schematic view of the mounting structure of the load lock fatigue reliability test apparatus for a loader according to the present invention;
FIG. 6 is a flow chart of a method of processing a loader test load spectrum of the present invention;
FIG. 7 is a schematic diagram of a local coordinate system of the present invention;
FIG. 8 is a schematic diagram of a global coordinate system of the present invention;
FIG. 9 is a schematic representation of a calculation of bucket tooth tip load in a local coordinate system in accordance with the present invention;
FIG. 10 is a schematic illustration of the calculation of loading force for a test actuator of the present invention;
FIG. 11 is a loading schematic of the present invention;
FIG. 12 is a graph showing the loading force Fload time history of an actuator according to the present invention;
in the figure: 1. the hydraulic device comprises a base, 1-1, a T-shaped groove, 2, a rigid wall, 2-1, a mounting hole, 3, an actuator, 3-1, a hydraulic cylinder, 3-2, a spherical hinge joint, 3-3, an actuator fixing seat, 3-4, a bucket fixing seat, 4, a front frame support, 4-1, a front frame connecting plate, 4-2, a cylinder, 4-3, a V-shaped fixing block, 4-4, a front support body, 5, a rear frame support, 5-1, a rear frame connecting plate, 5-2, rectangular connecting square steel, 5-3, rectangular connecting blocks, 5-4, triangular reinforcing plates, 5-5, a rear support body, 6 and a bucket.
Detailed Description
The present invention will be described in further detail below in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the terms used herein in this description of the invention are for the purpose of describing particular embodiments only and are not intended to be limiting of the invention.
As shown in fig. 1, 2 and 3, a fatigue reliability test device for a weight-related part for a loader comprises a front frame support 4, a rear frame support 5, an actuator 3 and a rigid wall 2;
the two front frame supports 4 are symmetrically arranged, each front frame support 4 comprises a front support body 4-4, a front frame connecting plate 4-1, a cylinder 4-2 and four V-shaped fixing blocks 4-3 are arranged on the front support body 4-4, the lower two V-shaped fixing blocks 4-3 are fixed on the front support body 4-4, if the lower two V-shaped fixing blocks 4-3 can be fixed in a welding or bolting mode, the cylinder 4-2 is fixed between the lower two V-shaped fixing blocks 4-3, the upper two V-shaped fixing blocks 4-3 are fixed at the bottom of the front frame connecting plate 4-1, the cylinder 4-2 is in clearance fit with the upper two V-shaped fixing blocks 4-3, and the front frame support 4 is used for supporting a front frame and enabling the front frame to follow up when a loader acts;
the two rear frame supports 5 are symmetrically arranged, the rear frame support 5 comprises a rear support body 5-5, a rear frame connecting plate 5-1 and a rectangular connecting square steel 5-2 are arranged on the rear support body 5-5, rectangular connecting blocks 5-3 perpendicular to the rectangular connecting square steel 5-2, triangular reinforcing plates 5-4 and slotted holes matched with the rectangular connecting blocks 5-3 in shape are symmetrically arranged on the rectangular connecting square steel 5-2, the rectangular connecting blocks 5-3 can be effectively arranged on the rectangular connecting square steel 5-2 through the slotted holes, and the stability of the whole structure is improved by means of the cooperation of the rectangular connecting square steel 5-2, the rectangular connecting blocks 5-3 and the triangular reinforcing plates 5-4; the rear frame support 5 is used for supporting a rear frame, and the front and rear frame supports can simulate the supporting effect of tires on the front and rear frames;
one end of the actuator 3 is adjustably mounted on the rigid wall 2, and the other end is connected with the loader bucket.
As a modification of the embodiment, as shown in fig. 1 and 4, the actuator 3 includes a hydraulic cylinder 3-1, a spherical joint 3-2, an actuator fixing base 3-3, and a bucket fixing base 3-4;
the two ends of the hydraulic oil cylinder 3-1 are respectively connected with the actuator fixing seat 3-3 and the bucket fixing seat 3-4 through spherical hinge joints 3-2, the hydraulic oil cylinder 3-1 can rotate around the spherical hinge joints 3-2 distributed at the front end and the rear end of the hydraulic oil cylinder, and the resultant force of the vertical load and the horizontal load born by the actual working of the working device of the loader can be loaded on the bucket of the loader; the actuator fixing seat 3-3 is used for connecting the actuator 3 with the rigid wall 2, a series of equidistant through holes are formed in the actuator fixing seat 3-3, and the bucket fixing seat 3-4 is used for connecting the hydraulic cylinder 3-1 and the bucket 6.
As an improvement of the embodiment, as shown in fig. 1 and fig. 4, a series of equidistant through holes are formed in the actuator fixing seat 3-3, further, a plurality of mounting holes 2-1 matched with the through holes in the actuator fixing seat 3-3 are formed in the rigid wall 2, and the connection positions of the actuator 3 and the rigid wall 2 can be effectively adjusted by means of matching the through holes with the mounting holes 2-1.
As an improvement of the embodiment, as shown in fig. 5, the device further comprises a base 1, wherein a plurality of rows of T-shaped grooves 1-1 which are arranged in parallel at equal intervals are arranged on the base 1;
the rigid wall 2, the front frame support 4 and the rear frame support 5 are movably mounted on the base 1 through T-shaped bolts, so that the distance between each part is adjustable, and the device is suitable for fatigue tests of loader working devices of different models.
In addition, the invention also provides a loading method for the fatigue reliability test of the weight-related part for the loader, and the loading device for the fatigue reliability test of the weight-related part for the loader is adopted;
firstly, acquiring data such as tested hinge point force, system pressure, oil cylinder displacement and the like, and processing to obtain a bucket tooth tip load spectrum;
then, calculating root mean square values of the vertical and horizontal loads of the bucket tooth point load spectrum in each shoveling process by extracting the vertical and horizontal loads of the bucket tooth point load spectrum in the shoveling process, and averaging the root mean square values of the vertical and horizontal loads of all shoveling processes to obtain the magnitudes of the vertical loads and the horizontal loads of the bucket tooth point in the shoveling process, so that the loading angle of the test actuator is determined;
and finally, determining an oblique loading load spectrum of the test actuator according to the load in the vertical direction of the load spectrum in the bucket tooth sharp digging process and the loading angle of the test actuator, and further determining a sinusoidal loading spectrum block of the bench test.
In the test, the actuator 3 obliquely arranged between the rigid wall 2 and the bucket 6 provides loading force, the loading position of the shoveling working condition is at the position which is far from the front end of the cutting edge of the bucket of the loader in the front-back direction, and the loading position of the bucket 6 in the left-right direction is at the middle position.
When the actuator 2 is extended, pressure is provided downwards, and the component forces formed in the horizontal direction and the vertical direction respectively simulate the insertion resistance and the digging resistance of the wheel loader; the upward lifting force is provided when the actuator 2 is contracted, and the impact of the stack on the bucket bottom plane caused by the inclination of the bucket bottom plane in the horizontal direction during the insertion operation of the loader is simulated. And respectively communicating the large cavity and the small cavity of the movable arm cylinder at two sides, locking the locking valve, observing internal leakage and sedimentation in the test process, and supplementing pressure by adopting a loader after a certain amount of internal leakage and sedimentation is reached.
In the fatigue test process, a plurality of time nodes are selected, a dynamic stress test device is used, for example, a force sensor is used for acquiring hinge point force, and dynamic stress data acquisition is carried out on the front frame. The front frame stress measurement point positions should be selected by referring to the finite element analysis results and combining with after-sales service records of similar structural products, and the stress measurement points should include stress concentration points and possible dangerous points.
As shown in fig. 6-12, the specific flow is as follows:
determining the hinge point force time histories of the movable arm (left) and the bucket, the hinge point force time histories of the movable arm (right) and the bucket in a local coordinate system according to the force sensor data;
the local coordinate system is shown in fig. 7, the center of the hinge point of the movable arm and the bucket is taken as an origin, the connecting line of the origin, the pull rod and the hinge point of the bucket is taken as a Y-axis forward direction, the origin is crossed and is vertical to the Y-axis, the pull rod is directed from the origin to the X-axis forward direction, and the Z-axis is determined by a right-hand rule;
the global coordinate system is shown in fig. 8, the stress point of the bucket is taken as an origin, the direction parallel to the ground and pointing to the pull rod is taken as the X-axis forward direction, the vertical upward direction is taken as the Y-axis forward direction, and the Z-axis is determined by the right-hand rule;
the angle is positive with counterclockwise rotation and negative with clockwise rotation;
determining the displacement time histories of the movable arm cylinder and the rocker arm cylinder according to the displacement sensor data;
establishing a dynamic model of a loader working device in dynamic software;
adjusting the dynamic model to the zero-moment positions of the movable arm cylinder and the rocker arm cylinder;
obtaining an included angle between a Y axis and a vertical direction of a local coordinate system of the zero time position;
performing kinematic simulation according to the displacement time histories of the movable arm cylinder and the rocker arm cylinder to obtain the angle time histories of the bucket and the ground and the angle time histories of the pull rod and the Y-axis of the local coordinate system;
determining the component force time histories of the pull rod force in all directions under the local coordinate system according to the angle time histories of the pull rod and the Y axis of the local coordinate system, wherein the component force time histories of the pull rod force in all directions under the local coordinate system are specifically shown in (1) to (2):
Fx＝F*sinA； (1)
Fy＝F*cosA； (2)
wherein Fx is the component force of the pull rod force on the X axis under the local coordinate system, fy is the component force of the pull rod force on the Y axis under the local coordinate system, F is the pull rod force, A is the angle between the pull rod and the Y axis of the local coordinate system;
the bucket tooth tip load in the local coordinate system is calculated as shown in fig. 9, specifically:
the mechanical equilibrium equations are considered under the local coordinate system as shown in (3) to (7),
∑Fx＝0：Fcx+Fax+Fbx+Fix＝0； (3)
∑Fy＝0：-Fcy+Fay+Fby+Fiy＝0 (4)
∑Mx＝0：Mcx+Fby*L2–Fay*L2＝0； (5)
∑My＝0：Mcy+Fax*L2–Fbx*L2＝0； (6)
∑Mz＝0：Mcz+(Fay+Fby+Fiy)*L3–(Fax+Fbx)*L4–Fix*(L1+L4)＝0； (7)
wherein a refers to a movable arm (left) and a bucket hinge point, b refers to a movable arm (right) and a bucket hinge point, i refers to a pull rod and a bucket hinge point, c refers to a bucket stress point, fax is a component force of an a point hinge point force on an X axis under a local coordinate system, fay is a component force of an a point hinge point force on a Y axis under a local coordinate system, fbx is a component force of a b point hinge point force on an X axis under a local coordinate system, fby is a component force of a b point hinge point force on a Y axis under a local coordinate system, fix is a component force of an i point hinge point force on an X axis under a local coordinate system, fix is a component force of an i point hinge point force on a Y axis under a local coordinate system, fcx is a component force of a bucket stress on an X axis under a local coordinate system, fcy is a component force of a bucket stress on a Y axis under a local coordinate system, mcx is a torque of a bucket stress on an X axis under a local coordinate system, mcy is a torque of a bucket stress on a Y axis under a local coordinate system, mcz is a torque of a point under a local coordinate system, L1 is a point is an origin, L2 is a projected distance of a point from an origin on an origin, and a distance of a point is a projected distance of a from an origin on an origin is 3 from the origin, and a distance of a point is a projected distance of an origin is from the origin;
calculating the bucket tooth point load in the whole movement process under the global coordinate system from the bucket tooth point load under the local coordinate system, wherein the bucket tooth point load is specifically as shown in (8) to (12):
Fx＝cos(B+C)*fx+sin(B+C)*fy； (8)
Fy＝-sin(B+C)*fx+cos(B+C)*fy； (9)
Mx＝mx； (10)
My＝my； (11)
Mz＝mz； (12)
wherein Fx, fy, mx, my, mz is the component force of the bucket tooth tip load along the X axis, the component force along the Y axis, the torque around the X axis, the torque around the Y axis and the torque around the Z axis in the global coordinate system, fx, fy, mx, my, mz is the component force of the bucket tooth tip load along the X axis, the component force along the Y axis, the torque around the X axis, the torque around the Y axis and the torque around the Z axis in the local coordinate system, the angle B is the included angle between the Y axis and the vertical direction in the zero moment position, and the angle C is the angle between the bucket and the ground;
according to the load time history of the bucket tooth tip in the whole motion process under the global coordinate system, extracting the load time history of the bucket tooth tip in the shoveling process by using the values of Fx and Fy;
the test actuator is placed obliquely between the rigid wall 2 and the bucket 6 to apply a load, and the loading angle of the test actuator is determined mainly by referring to the relation between the bucket tooth tips Fx and Fy during the shoveling process. And (3) analyzing load data of Fx and Fy in the load spectrum of fig. 12 under the ground digging gesture, and comprehensively determining a loading angle by considering the average value and the root mean square value to obtain an included angle between the placement of the actuator and the horizontal direction of 40.6 degrees.
As known from finite element simulation, the influence of the vertical acting force on the structural stress level is far greater than that of the horizontal acting force, so Fy is taken as a main basis when the loading force is calculated, and the loading force F and the horizontal load Fx of the test actuator are calculated by combining the loading angle, and the loading spectrum of the loading force Fof the actuator is shown in FIG. 10:
F＝Fy/sinD； (13)
f is the loading force of the test actuator, fy is the component force of the load of the tooth tip of the bucket along the Y axis in the shoveling process under the global coordinate system, and the angle D is the included angle between the test actuator and the horizontal direction.
And eliminating some singular values with little influence on fatigue damage from test data to obtain a series of load cycles with different amplitude values and average values, dividing the load amplitude values into spectrums according to multi-stage unequal intervals, compiling an acceleration spectrum of the structure by utilizing a relative equivalent damage principle, and simulating a real operation load according to the operation characteristics of a loader by adopting a low-high-low loading sequence to obtain a test loading spectrum block, wherein a loading wave is a sine wave, and a loading schematic diagram is shown in fig. 12.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, or alternatives falling within the spirit and principles of the invention.
Claims (8)
1. The fatigue reliability test device for the weight-closing part for the loader is characterized by comprising a front frame support (4), a rear frame support (5), an actuator (3) and a rigid wall (2);
the two front frame supports (4) are symmetrically arranged, each front frame support (4) comprises a front support body (4-4), a front frame connecting plate (4-1), a cylinder (4-2) and V-shaped fixing blocks (4-3) are arranged on each front support body (4-4), the two V-shaped fixing blocks (4-3) below are fixed on the front support bodies (4-4), the cylinder (4-2) is fixed between the two V-shaped fixing blocks (4-3) below, the two V-shaped fixing blocks (4-3) above are fixed at the bottoms of the front frame connecting plates (4-1), the cylinder (4-2) is in clearance fit with the two V-shaped fixing blocks (4-3) above, and the front frame supports (4) are used for supporting the front frame and enabling the front frame to follow up when the loader acts;
the two rear frame supports (5) are symmetrically arranged, the rear frame supports (5) comprise rear support bodies (5-5), rear frame connecting plates (5-1) and rectangular connecting square steel (5-2) are arranged on the rear support bodies (5-5), rectangular connecting blocks (5-3) and slotted holes matched with the rectangular connecting blocks (5-3) in shape are arranged on the rectangular connecting square steel (5-2), and the rear frame supports (5) are used for supporting a rear frame;
one end of the actuator (3) is adjustably arranged on the rigid wall (2), and the other end of the actuator is connected with the loader bucket.
2. The device for testing fatigue reliability of a weight-related member for a loader according to claim 1, wherein the actuator (3) comprises a hydraulic cylinder (3-1), an actuator fixing base (3-3) and a bucket fixing base (3-4);
the two ends of the hydraulic oil cylinder (3-1) are respectively connected with the actuator fixing seat (3-3) and the bucket fixing seat (3-4) through spherical hinge joints (3-2), and the hydraulic oil cylinder (3-1) can rotate around the spherical hinge joints (3-2).
3. The device for testing the fatigue reliability of the weight closing member for the loader according to claim 2, wherein the actuator fixing seat (3-3) is arranged on the rigid wall (2), and a plurality of through holes are formed in the actuator fixing seat (3-3).
4. A load lock weight fatigue reliability test apparatus according to claim 3, wherein the rigid wall (2) is provided with a plurality of mounting holes (2-1).
5. The fatigue reliability test device for the weight closing member for the loader according to claim 1, wherein a triangular reinforcing plate (5-4) is arranged between the rear frame connecting plate (5-1) and the rectangular connecting square steel (5-2).
6. The device for testing the fatigue reliability of the weight closing member for the loader according to claim 1 is characterized by further comprising a base (1), wherein a plurality of T-shaped grooves (1-1) are formed in the base (1), and the rigid wall (2), the front frame support (4) and the rear frame support (5) are movably mounted on the base (1) through bolts.
7. A load method of a fatigue reliability test of a weight-related member for a loader, characterized in that the load device for a fatigue reliability test of a weight-related member for a loader according to any one of claims 1 to 6 is used;
firstly, acquiring data such as tested hinge point force, system pressure, oil cylinder displacement and the like, and processing to obtain a bucket tooth tip load spectrum;
then, calculating root mean square values of the vertical and horizontal loads of the bucket tooth point load spectrum in each shoveling process by extracting the vertical and horizontal loads of the bucket tooth point load spectrum in the shoveling process, and averaging the root mean square values of the vertical and horizontal loads of all shoveling processes to obtain the magnitudes of the vertical loads and the horizontal loads of the bucket tooth point in the shoveling process, so that the loading angle of the test actuator is determined;
and finally, determining an oblique loading load spectrum of the test actuator according to the load in the vertical direction of the load spectrum in the bucket tooth sharp digging process and the loading angle of the test actuator, and further determining a sinusoidal loading spectrum block of the bench test.
8. The method for loading a load lock for a loader according to claim 7, comprising:
determining the hinge point force time histories of the left movable arm and the bucket, the hinge point force time histories of the right movable arm and the bucket and the pull rod force time histories under the local coordinate system according to the force sensor data;
determining the displacement time history of the movable arm cylinder and the rocker arm cylinder in the movement process according to the data of the displacement sensor;
determining an included angle between a Y axis of a local coordinate system at a zero moment and a vertical direction, an angle time history of a bucket and the ground and an angle time history of a pull rod and a Y axis of the local coordinate system according to the displacement time history of the movable arm cylinder and the displacement time history of the rocker arm cylinder;
determining the component force time histories of the pull rod force in all directions under the local coordinate system according to the angle time histories of the pull rod and the Y axis of the local coordinate system;
determining the bucket tooth tip load time histories under the local coordinate system according to the hinge point force time histories of the left movable arm and the bucket, the hinge point force time histories of the right movable arm and the bucket and the component force time histories of the pull rod force in all directions under the local coordinate system;
determining the bucket tooth tip load time history in the whole movement process under the global coordinate system according to the bucket tooth tip load time history under the local coordinate system, the angle time history of the bucket and the ground, and the included angle between the Y axis of the zero-moment position local coordinate system and the vertical direction;
extracting the bucket tooth tip load time histories in the shoveling process according to the bucket tooth tip load time histories in the whole motion process under the global coordinate system;
determining a loading angle of the test actuator according to the load time history of the tooth tip of the bucket in the shoveling process;
determining the loading force time history of the test actuator according to the loading time history of the bucket tooth tip in the vertical direction and the loading angle of the test actuator in the shoveling process;
removing singular values from test data to obtain a series of load cycles with different amplitude values and average values, dividing the load amplitude values into spectrums according to multistage unequal intervals, compiling an acceleration spectrum of the structure by utilizing a relative equivalent damage principle, and simulating a real operation load according to the operation characteristics of a loader by adopting a low-high-low loading sequence to obtain test loading spectrum blocks, wherein loading waves are sine waves;
and loading the obtained load spectrum of the test actuator onto the fatigue reliability test device of the weight-related part for the loader through the actuator.
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| CN202310520881.9A CN116519328A (en) | 2023-05-10 | 2023-05-10 | Device and method for testing fatigue reliability of weight-related parts for loader |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310520881.9A CN116519328A (en) | 2023-05-10 | 2023-05-10 | Device and method for testing fatigue reliability of weight-related parts for loader |
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