Forklift gantry structural strength simulation analysis method

Abstract

The invention discloses a simulation analysis method for the structural strength of a forklift portal frame, and belongs to the technical field of computer-aided engineering technologies. The forklift portal structural strength simulation analysis method comprises the steps that all sub-portals in a forklift portal are determined, and a corresponding sub-portal model is established for each sub-portal; establishing a relative motion simulation model based on the sub-portal model; defining boundary conditions of the relative motion simulation model; performing nonlinear contact analysis on the relative motion simulation model to obtain a stress state and a deformation state of the sub-portal model; and according to the stress state and the deformation state, generating a simulation analysis result of the structural strength of the forklift portal frame. According to the method, the forklift gantry can be simulated on the premise that the calculated amount is reduced, and the structural strength of the forklift gantry is efficiently detected.

Description

Technical Field

[0001] The present application relates to the field of computer-aided engineering technology, and in particular to a forklift gantry structure strength simulation analysis method. Background Art

[0002] The forklift mast is a key component of the forklift. The forklift mast includes multiple sub-masts such as the inner mast, middle mast and outer mast. The lifting and tilting of goods are achieved through rollers, channel steels, chains and cylinders to ensure the stability and safety of the operation.

[0003] In order to test the structural strength of the forklift mast, the relevant technology usually conducts systematic overall modeling of the forklift mast. However, since the established mast model has many finite element meshes and the roller channel steels of the mast are in nonlinear contact, the amount of calculation is very large, making it impossible for the computer to carry out the calculation, or even if it can be calculated, it is difficult to converge.

[0004] Therefore, how to simulate the forklift mast while reducing the amount of calculation and efficiently detect the structural strength of the forklift mast is a technical problem that technical personnel in this field currently need to solve. Summary of the invention

[0005] The purpose of this application is to provide a forklift mast structural strength simulation analysis method, system, electronic equipment and storage medium, which can simulate the forklift mast while reducing the amount of calculation and efficiently detect the structural strength of the forklift mast.

[0006] In order to solve the above technical problems, the present application provides a forklift gantry structure strength simulation analysis method, comprising:

[0007] Determine all sub-gantry in the forklift gantry, and establish a corresponding sub-gantry model for each of the sub-gantry; wherein each of the sub-gantry is provided with rollers and channel steels, and the sub-gantry model is a finite element mesh model;

[0008] A relative motion simulation model is established based on the sub-gantry model; wherein the relative motion simulation model is used to simulate the relative motion between the roller and the channel steel during the lifting process of the sub-gantry;

[0009] Defining boundary conditions of the relative motion simulation model; wherein the boundary conditions include displacement constraints, forces, contacts and gravity fields;

[0010] Performing nonlinear contact analysis on the relative motion simulation model to obtain the stress state and deformation state of the sub-gantry model;

[0011] The forklift portal frame structure strength simulation analysis result is generated according to the stress state and the deformation state.

[0012] Optionally, defining the boundary conditions of the relative motion simulation model includes:

[0013] defining corresponding displacement constraints for the roller in the relative motion simulation model;

[0014] In the relative motion simulation model, corresponding contacts are defined for the roller and the channel steel.

[0015] Optionally, the forklift mast comprises an inner mast and an outer mast, and the inner mast and the outer mast are further provided with a chain and an oil cylinder;

[0016] Accordingly, the boundary conditions of the relative motion simulation model are defined, including:

[0017] defining corresponding forces for the chain and the cylinder in the relative motion simulation model;

[0018] The force corresponding to the variable load curve is defined in the relative motion simulation model; wherein the variable load curve is used to describe the corresponding relationship between the height of the sub-gantry and the preset load during the sub-gantry lifting process, and the preset load includes the load of the roller and the roller seat.

[0019] Optionally, before defining the force corresponding to the variable load curve in the relative motion simulation model, the method further includes:

[0020] Calculate the load variation information of the roller and the roller seat during the lifting process of the sub-gantry by means of theoretical mechanics calculation or multi-body dynamic software simulation;

[0021] The variable load curve is drawn according to the load change information.

[0022] Optionally, also include:

[0023] In the relative motion simulation model, the structure corresponding to the oil cylinder is simplified into a beam unit.

[0024] Optionally, a corresponding sub-gantry model is established for each of the sub-gantry, including:

[0025] A corresponding sub-gantry model is established for each sub-gantry based on the symmetry plane, wherein the sub-gantry is a left-right symmetrical structure, and the sub-gantry model is a finite element mesh model of half of the sub-gantry.

[0026] Optionally, generating a simulation analysis result of the forklift mast structure strength according to the stress state and the deformation state includes:

[0027] Determine the maximum stress value of the sub-gantry model during the simulation according to the stress state;

[0028] Determine the maximum deformation amount of the sub-gantry model during the simulation process according to the deformation state;

[0029] Determining whether the maximum stress value is less than a stress threshold and the maximum deformation amount is less than a deformation threshold;

[0030] If yes, then generate a simulation analysis result that the structural strength of the forklift mast meets the preset requirements;

[0031] If not, a simulation analysis result is generated indicating that the structural strength of the forklift mast does not meet the preset requirements.

[0032] The present application also provides a forklift gantry structure strength simulation analysis system, the system comprising:

[0033] The first modeling module is used to determine all the sub-gantry in the forklift gantry and establish a corresponding sub-gantry model for each of the sub-gantry; wherein the sub-gantry is provided with rollers and channel steels, and the sub-gantry model is a finite element mesh model;

[0034] A second modeling module is used to establish a relative motion simulation model based on the sub-gantry model; wherein the relative motion simulation model is used to simulate the relative motion between the roller and the channel steel during the lifting process of the sub-gantry;

[0035] A boundary condition definition module, used to define the boundary conditions of the relative motion simulation model; wherein the boundary conditions include displacement constraints, forces, contacts and gravity fields;

[0036] An analysis module, used for performing nonlinear contact analysis on the relative motion simulation model to obtain the stress state and deformation state of the sub-gantry model;

[0037] A judgment module is used to generate a simulation analysis result of the forklift portal frame structure strength according to the stress state and the deformation state.

[0038] The present application also provides a storage medium having a computer program stored thereon, and when the computer program is executed, the steps of the forklift gantry structure strength simulation analysis method are implemented.

[0039] The present application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor calls the computer program in the memory, the steps of the forklift gantry structure strength simulation analysis method are implemented.

[0040] The present application provides a method for simulating and analyzing the structural strength of a forklift gantry. The scheme determines all the sub-gantry in the forklift gantry and establishes a corresponding sub-gantry model for each sub-gantry. Based on the sub-gantry model, the present application can establish a relative motion simulation model for simulating the relative motion between the roller and the channel steel during the lifting process of the sub-gantry, and define the boundary conditions of the relative motion simulation model. By performing nonlinear contact analysis on the relative motion simulation model, the stress state and deformation state of the sub-gantry model can be obtained, and then the structural strength of the forklift gantry can be evaluated. The above process splits and simplifies the forklift gantry, establishes a relative motion simulation model between the split roller and the sub-gantry channel steel, greatly reduces the amount of calculation, and improves the efficiency of simulation analysis. Therefore, the present application can simulate the forklift gantry under the premise of reducing the amount of calculation, and efficiently detect the structural strength of the forklift gantry. The present application also provides a forklift gantry structural strength simulation analysis system, a storage medium and an electronic device, which have the above-mentioned beneficial effects and are not repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 A flow chart of a forklift gantry structure strength simulation analysis method provided in an embodiment of the present application;

[0043] Figure 2 A flowchart of a simulation analysis method based on forklift gantry splitting simplification provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of the overall three-dimensional back view structure of a three-stage gantry provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of the overall three-dimensional front view structure of a three-stage gantry provided in an embodiment of the present application;

[0046] Figure 5 A schematic structural diagram of a finite element mesh model of an inner gantry of a three-stage gantry provided in an embodiment of the present application;

[0047] Figure 6 A schematic structural diagram of a finite element mesh model of a middle gantry of a three-stage gantry provided in an embodiment of the present application;

[0048] Figure 7A schematic structural diagram of a finite element mesh model of an outer gantry of a three-stage gantry provided in an embodiment of the present application;

[0049] Figure 8 A schematic diagram of a gantry constraint setting provided in an embodiment of the present application;

[0050] Fig. 9 A schematic diagram of a roller displacement setting provided in an embodiment of the present application;

[0051] Fig.10 A schematic diagram of loading of a cylinder pressure, chain tension and gravity field provided in an embodiment of the present application;

[0052] Fig.11 A schematic diagram of a variable load curve provided in an embodiment of the present application;

[0053] Fig.12 A diagram showing the hinge point positions of a fork frame of a two-stage gantry provided in an embodiment of the present application;

[0054] Fig.13 A diagram showing the position of the inner door frame hinge points of a two-stage door frame provided in an embodiment of the present application;

[0055] Fig.14 A diagram showing the hinge point positions of a fork frame of a three-stage gantry provided in an embodiment of the present application;

[0056] Fig.15 A diagram showing the position of the inner door frame hinge points of a three-stage door frame provided in an embodiment of the present application;

[0057] Fig.16 A diagram showing the position of the hinge point of the middle mast of a three-stage mast provided in an embodiment of the present application;

[0058] Fig.17 A schematic diagram of the partial structure of a first forklift provided in an embodiment of the present application;

[0059] Fig.18 A schematic diagram of a partial structure of a second forklift provided in an embodiment of the present application;

[0060] Fig.19 A schematic diagram of the partial structure of a third forklift provided in an embodiment of the present application;

[0061] Fig. 20 A schematic diagram of the partial structure of a fourth forklift provided in an embodiment of the present application;

[0062] Fig.21 This is a schematic diagram of the partial structure of a fifth forklift provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0064] See below Figure 1 , Figure 1 A flow chart of a forklift mast structure strength simulation analysis method provided in an embodiment of the present application.

[0065] Specific steps may include:

[0066] S101: determining all sub-gantry in a forklift gantry, and establishing a corresponding sub-gantry model for each of the sub-gantry;

[0067] Among them, this embodiment can be applied to electronic equipment with simulation function, and the structural strength of the forklift mast is determined by simulating the lifting process of each sub-mast in the forklift mast. This embodiment can determine all sub-masts of the forklift mast according to the forklift model or the forklift appearance, and the forklift mast can include a second-level sub-mast, a third-level sub-mast, and a fourth-level or higher sub-mast.

[0068] The above-mentioned sub-gantry is equipped with rollers and channel steels, and the sub-gantry model is a finite element mesh model. The rollers are installed on each sub-gantry to reduce friction and ensure that each part of the gantry can slide smoothly. The channel steel is installed on each sub-gantry to guide the movement of the rollers and ensure that each part of the gantry moves according to the predetermined trajectory.

[0069] If the forklift mast includes a secondary sub-mast, the sub-masts of the forklift mast include an inner mast and an outer mast; if the forklift mast includes a tertiary sub-mast, the sub-masts of the forklift mast include an inner mast, a middle mast and an outer mast. The outer mast is the main supporting structure fixed to the forklift chassis, usually including rollers and channel steels; the middle mast is inside the outer mast, and the rollers slide in the channel steels to achieve up and down movement; the inner mast is inside the middle mast, and the rollers slide in the channel steels of the middle mast to achieve more precise up and down movement.

[0070] S102: establishing a relative motion simulation model based on the sub-gantry model;

[0071] Among them, this step can import the sub-gantry model into the simulation software to obtain a relative motion simulation model. The relative motion simulation model is used to simulate the relative motion between the roller and the channel steel during the lifting process of the sub-gantry (including the lifting process and the lowering process). This embodiment can determine the relative motion equation of the roller and the channel steel according to the relative motion relationship between the sub-gantry models, and then establish a relative motion simulation model based on the above relative motion equation. The gantry roller rolls on the gantry channel steel, and the process corresponding to the relative motion model is: assuming that the inner gantry or the outer gantry is fixed, the roller rolls up and down on the channel steel to simulate the process of the gantry lifting and lowering.

[0072] S103: defining boundary conditions of the relative motion simulation model;

[0073] After establishing the relative motion simulation model, the boundary conditions of the relative motion simulation model can also be defined. The boundary conditions define the physical behavior on the boundary of the motion simulation model, and the above boundary conditions include displacement constraints, forces, contacts, and gravity fields. By defining displacement constraints, forces, contacts, and gravity fields, it can be ensured that the relative motion simulation model can accurately reflect the actual working conditions.

[0074] S104: performing nonlinear contact analysis on the relative motion simulation model to obtain a stress state and a deformation state of the sub-gantry model;

[0075] Among them, this embodiment can use a nonlinear solver to perform nonlinear contact analysis on the relative motion simulation model, and then determine the stress distribution diagram and deformation distribution diagram of the sub-gantry during the lifting process, and obtain the stress state and deformation state of the sub-gantry model.

[0076] S105: generating a simulation analysis result of the forklift mast structure strength according to the stress state and the deformation state.

[0077] Among them, the stress state includes the stress data during the sub-gantry lifting process, and the deformation state simulates the deformation data during the sub-gantry lifting process; according to the combined stress data and deformation data, this step can determine whether the structural strength of the gantry meets the design requirements, and then obtain the simulation analysis results of the structural strength of the forklift gantry. The content of the above simulation analysis results may include: the structural strength of the forklift gantry meets the preset requirements, or the structural strength of the forklift gantry does not meet the preset requirements.

[0078] This embodiment determines all the sub-gantry in the forklift gantry, and establishes a corresponding sub-gantry model for each sub-gantry. Based on the sub-gantry model, this embodiment can establish a relative motion simulation model for simulating the relative motion between the roller and the channel steel during the lifting and lowering process of the sub-gantry, and define the boundary conditions of the relative motion simulation model. By performing nonlinear contact analysis on the relative motion simulation model, the stress state and deformation state of the sub-gantry model can be obtained, and then the structural strength of the forklift gantry can be evaluated. The above process splits and simplifies the forklift gantry, and establishes a relative motion simulation model between the split roller and the sub-gantry channel steel, which greatly reduces the amount of calculation and improves the efficiency of simulation analysis. Therefore, this embodiment can simulate the forklift gantry under the premise of reducing the amount of calculation, and efficiently detect the structural strength of the forklift gantry.

[0079] As for Figure 1 Further introduction to the corresponding embodiment, this embodiment can define the boundary conditions of the relative motion simulation model in the following way: define corresponding displacement constraints (roller center point, rolling freedom, initial position, etc.) for the roller in the relative motion simulation model; define corresponding contacts (such as contact point, force, friction coefficient, etc.) for the roller and the channel steel in the relative motion simulation model.

[0080] Furthermore, the forklift mast comprises an inner mast and an outer mast, and the inner mast and the outer mast are further provided with chains and oil cylinders. The chains are used to transmit lifting force to ensure synchronous movement of the inner mast and the middle mast. The oil cylinders are used to provide lifting force and tilting force to control the lifting and tilting movements of the mast.

[0081] Correspondingly, this embodiment can also define corresponding forces (cylinder pressure, chain tension) for the chain and the cylinder in the relative motion simulation model; this embodiment can also define the forces corresponding to the variable load curve in the relative motion simulation model; wherein, the variable load curve is used to describe the corresponding relationship between the sub-gantry height and the preset load during the sub-gantry lifting process, and the preset load includes the loads of the rollers and the roller seats.

[0082] As for Figure 1 Further introduction to the corresponding embodiment, before defining the force corresponding to the variable load curve in the relative motion simulation model, the variable load curve can also be generated in the following way: calculating the load change information of the roller and the roller seat during the lifting and lowering of the sub-gantry through theoretical mechanics calculations or multi-body dynamics software simulations; and drawing the variable load curve based on the load change information.

[0083] As a feasible implementation, in this embodiment, the structure corresponding to the oil cylinder can be simplified into a beam unit in the relative motion simulation model. The above method can reduce the amount of calculation.

[0084] As for Figure 1 Further introduction to the corresponding embodiment, the sub-gantry is a bilaterally symmetrical structure, and the sub-gantry model can be established in the following manner: a corresponding sub-gantry model is established for each sub-gantry based on the symmetry plane, wherein the sub-gantry model is a finite element mesh model of half of the sub-gantry. The above process utilizes the symmetry of the sub-gantry and only models half of the sub-gantry, which significantly reduces the amount of calculation and calculation time.

[0085] As for Figure 1 Further introduction to the corresponding embodiment can be made in the following way to determine whether the structural strength of the forklift mast meets the preset requirements: determine the maximum stress value of the sub-gantry model in the simulation process (simulating the sub-gantry lifting process) according to the stress state; determine the maximum deformation of the sub-gantry model in the simulation process (simulating the sub-gantry lifting process) according to the deformation state; determine whether the maximum stress value is less than the stress threshold and the maximum deformation is less than the deformation threshold; if so, generate a simulation analysis result that the structural strength of the forklift mast meets the preset requirements; if not, generate a simulation analysis result that the structural strength of the forklift mast does not meet the preset requirements.

[0086] The process described in the above embodiment is explained below through an embodiment in actual application.

[0087] At present, the structural design simulation analysis of forklift gantry only calculates the static strength of certain working conditions (gantry lifting in the middle or lifting to the top), and then refers to the material yield limit and empirical safety factor to determine whether the gantry components meet the structural strength requirements. However, the gantry is a dynamic mechanism at work, and the gantry may not be in the most dangerous state in certain working conditions (lifting in the middle or lifting to the top), so it is not comprehensive to analyze only certain working conditions, so the above simulation method has certain defects; some also systematically model the gantry as a whole, but because the finite element meshes of the established gantry model are large, and the roller channel steels of the gantry are in nonlinear contact, the amount of calculation is very large, making it impossible for the computer to carry out the calculation, or even if it can be calculated, it is not easy to converge; and the chain modeling of the lifting mechanism in the gantry is also relatively cumbersome, which also makes the calculation scale of the gantry model larger, and the difficulty of modeling and calculation is also greater.

[0088] In response to the technical problems existing in the above-mentioned related technologies, this embodiment proposes a gantry strength verification scheme based on nonlinear simulation analysis based on the simplification of forklift gantry splitting. This scheme splits the secondary forklift gantry into an outer gantry and an inner gantry, and splits the tertiary gantry into an outer gantry, a middle gantry and an inner gantry. A simulation model of the relative motion between the roller and the sub-gantry channel steel after splitting is established, the contact between the roller and the channel steel is defined, the displacement of the roller relative to the channel steel is set, and the roller and the roller seat are given a force that changes with the displacement (the relative displacement of the roller and the channel steel refers to the lifting process of the gantry). The simulation model is solved to obtain the stress results of the gantry, and whether the process of lifting the gantry from the bottom to the top meets the structural strength requirements. The variable load of the contact between the roller and the gantry channel steel in this scheme is solved by theoretical mechanics calculation or by multi-body dynamics simulation.

[0089] Compared with only calculating the static strength of the gantry under certain working conditions (gantry lifted to the center or lifted to the top), the analysis method of this embodiment can obtain the stress changes of each component of the gantry during the entire lifting process of the forklift gantry, obtain more comprehensive simulation results, and check whether each component meets the structural strength requirements during the process of the gantry lifting from the bottom to the top; compared with systematic overall modeling and simulation, the modeling and simulation method provided in this embodiment can split and simplify the gantry, and establish a relative motion simulation model of the split roller and the sub-gantry channel steel, which greatly reduces the amount of calculation and improves the efficiency of simulation analysis.

[0090] See also Figure 2 , Figure 2 A flowchart of a simulation analysis method based on the simplification of forklift gantry splitting provided in the embodiment of the present application, the process is as follows: determine the gantry level (two-stage gantry or three-stage gantry) according to the gantry three-dimensional model, split the two-stage gantry into inner gantry and outer gantry, split the three-stage gantry into inner gantry, middle gantry and outer gantry; establish a relative motion simulation model between the roller and the sub-gantry channel steel, define the constraints of the gantry sub-model, define the contact between the roller and the channel steel, assign the roller displacement relative to the gantry channel steel, assign the roller and the roller seat a force that changes with the lifting of the gantry, submit the solution to obtain the simulation stress and deformation results, perform post-processing and check whether the stress of the gantry from the bottom to the top meets the structural strength requirements. This embodiment can calculate the changing loads of the rollers and roller seats during the lifting of the gantry through theoretical mechanics, and can also use multi-body dynamics software to calculate the changing loads of the rollers and roller seats during the lifting of the gantry, so as to draw a variable load curve.

[0091] In the simulation analysis process, the gantry has two-level gantry and three-level gantry according to the number of levels. The two-level gantry is divided into inner gantry and outer gantry, and the three-level gantry is divided into inner gantry, middle gantry and outer gantry. The relative motion simulation models of rollers and sub-gantry channel steels are established respectively; then the constraints of the gantry sub-model are defined, the contact between the rollers and the sub-gantry channel steels is defined, the displacement of the rollers relative to the gantry channel steels is given, and the forces that change with the lifting of the gantry are given to the rollers and roller seats (this force can be obtained through theoretical mechanics calculations or multi-body dynamics software simulation calculations, and then given in the form of variable load curves). Next, the set model is submitted for solution to obtain the corresponding stress and deformation results. Finally, the analysis results are post-processed to check whether the stress of the gantry from the bottom to the top meets the strength requirements.

[0092] The following is an example of a forklift mast obtained in practice to illustrate the above simulation method. The mast uses a 4.5m three-stage mast of a 3.5t counterbalanced forklift, with a rated lifting capacity of 3.5 tons and a load center distance of 500mm. The main structure includes a three-stage mast frame structure (i.e., inner mast, middle mast, outer mast), a fork frame body, a pair of forks, a pair of rear lifting hydraulic cylinders, a front lifting hydraulic cylinder, a pair of rear sprocket mechanisms, a front sprocket structure, etc. Please refer to Figure 3 , Figure 3 A schematic diagram of the overall three-dimensional back view structure of a three-stage gantry provided in an embodiment of the present application, 301 represents an inner gantry, 302 represents a sprocket, 303 represents a chain, 304 represents a middle gantry, 305 represents an outer gantry, and 306 represents a rear lifting hydraulic cylinder.

[0093] See also Figure 4 , Figure 4 A schematic diagram of the overall three-dimensional front view structure of a three-stage mast provided in an embodiment of the present application, 401 represents a fork frame body, 402 represents a front lifting hydraulic cylinder, 403 represents a tilting cylinder seat, 404 represents a tilting hydraulic cylinder, 405 represents a Haver seat, and 406 represents a cargo fork. The Haver seat is a structure used to connect the mast and the drive axle.

[0094] The specific steps of the simulation process are as follows:

[0095] The finite element mesh models of the inner, middle and outer masts are established respectively. Since the mast is a bilaterally symmetrical structure, the contact model of the roller mast channel steel cut in half is preferably used, which can reduce the amount of calculation. The established model is as follows: Figure 5 , Figure 6 and Figure 7 shown. Figure 5 A schematic structural diagram of a finite element mesh model of an inner gantry of a three-stage gantry provided in an embodiment of the present application, Figure 5 The finite element mesh model of the inner portal frame and the directions of the X, Y, and Z axes are shown in FIG. Figure 6A schematic structural diagram of a finite element mesh model of a middle gantry of a three-stage gantry provided in an embodiment of the present application, Figure 6 The finite element mesh model of the middle gantry and the directions of the X, Y, and Z axes are shown in FIG. Figure 7 A schematic structural diagram of a finite element mesh model of an outer gantry of a three-stage gantry provided in an embodiment of the present application, Figure 7 The finite element mesh model of the outer gantry is shown in FIG, as well as the directions of the X, Y, and Z axes.

[0096] The simulation setting steps for the inner mast, middle mast, and outer mast are similar. Here we will explain the simulation analysis steps for the outer mast.

[0097] See also Figure 8 , Figure 8 A schematic diagram of a gantry constraint setting provided in an embodiment of the present application shows that the tilt hydraulic cylinder is simplified into a beam unit, a Havers seat, a symmetric mirror plane, a middle gantry roller, and the directions of the X, Y, and Z axes. Figure 8 Here, (1) represents displacement along X, (2) represents displacement along Y, (3) represents displacement along Z, (5) represents rotation around Y, and (6) represents rotation around Z.

[0098] The lower middle mast roller constrains the displacement in the X direction and the rotation around the Z axis, the lower Haversian seat constrains the displacement in the YZ direction and the rotation around the YZ axis, the tilt cylinder constrains the displacement in the YZ direction, and constrains the X direction of the symmetric mirror surface. Fig. 9 , Fig. 9 A schematic diagram of roller displacement setting provided in an embodiment of the present application. In this embodiment, the displacement of the roller of the middle mast along the positive direction of the Y axis can be further set (i.e., the roller can remain in a vertical state and move along the Y direction in the channel steel), simulating the relative displacement and rolling of the roller and the channel steel during the mast lifting process. Compared with the outer mast, the inner mast has an additional displacement of the side cylinder support seat. The X direction is the left and right direction of the mast or is regarded as the direction along the crossbeam, and the Z direction is the front and back direction of the mast.

[0099] This embodiment loads the cylinder pressure and chain tension (these two forces are constant forces during the slow lifting of the gantry), loads the middle gantry roller contact force and the outer gantry roller shaft contact force that change with the lifting of the gantry, and imparts a gravity field. The above loading forces can also be obtained by simulation and solution using multi-body dynamics software.

[0100] See also Fig.10 , Fig.10A loading schematic diagram of cylinder pressure, chain tension and gravity field provided in an embodiment of the present application, showing the adding positions of outer mast roller shaft contact force (variable force), chain tension (constant force), cylinder pressure (constant force) and middle mast roller contact force (variable force). The tilt hydraulic cylinder in the figure is simplified to a beam unit, and the figure also shows the gravity field G (negative direction of the Y axis).

[0101] In this embodiment, the variable force obtained by theoretical mechanics calculation or multi-body dynamics software simulation can be plotted as a variable load curve, and then assigned to the above-mentioned middle mast roller contact force and outer mast roller shaft contact force. Fig.11 , Fig.11 This is a schematic diagram of a variable load curve provided in an embodiment of the present application, in which the horizontal axis represents the height, the vertical axis represents the force of the roller, and E represents a certain power multiplied by 10.

[0102] After setting the above boundary conditions, submit the nonlinear contact solution to obtain the stress and deformation of the portal frame model, and determine whether the portal frame meets the structural strength requirements.

[0103] The following introduces the process of calculating the forces on two-stage and three-stage portal frames using theoretical mechanics methods.

[0104] The calculation process of the two-stage gantry loading force is as follows:

[0105] The interaction force between the fork frame and the inner mast is calculated by 3D software to confirm the mass of each mast component and the distance from the center of mass to the hinge point. Fig.12 As shown, the fork frame pull seat is the hinge point, and the parameters of the mast components are shown in Table 1. Fig.12 , Fig.12 A diagram of the hinge point positions of a fork frame body of a two-stage gantry provided in an embodiment of the present application, wherein 1201 represents an upper roller, 1202 represents a middle roller, 1203 represents a lower roller, 1204 represents a sprocket seat, and 1205 represents a hinge point.

[0106] Table 1 Parameters of the first type of gantry components

[0107]

[0108] When the fork frame is lifted to the top, the contact relationship between the upper, middle and lower rollers and the inner mast channel steel will change. First, the upper and lower rollers are in contact with the inner mast channel steel. When it is lifted to the top and is about to be lifted, the upper roller is separated from the inner mast channel steel, and the middle and lower rollers are switched to contact with the inner mast channel steel. Therefore, it is necessary to calculate the force of the rollers on the inner mast channel steel in these two working conditions, and measure the spacing between the rollers, and obtain that the spacing between the upper and lower rollers is L1, and the spacing between the middle and lower rollers is L2.

[0109] According to the parameters shown in Table 1, the single-side sprocket seat is subjected to (The force on the sprocket seat is twice the force on the hinge of the fork frame) Calculate according to formula (1):

[0110] Formula (1);

[0111] Roller force under upper and lower single-sided roller contact condition and Calculate according to formula (2):

[0112] Formula (2);

[0113] Roller force in middle and lower single-side roller contact condition and Calculate according to formula (3):

[0114] Formula (3);

[0115] g is the acceleration due to gravity, which is 9.81 m / s 2 .

[0116] The calculation process of the interaction force between the inner and outer gantry is as follows:

[0117] Use 3D software to confirm the mass of each component of the gantry and the distance between the center of mass and the hinge point. Fig.13 The parameters of the various components of the gantry are shown in Table 2.

[0118] Fig.13 This is a diagram of the position of the inner door frame hinge points of a two-stage door frame provided in an embodiment of the present application, in which 1301 represents the hinge point, 1302 represents the pull seat, 1303 represents the outer door frame roller, and 1304 represents the inner door frame roller.

[0119] Table 2 Parameters of the components of the second type of gantry

[0120]

[0121] When the inner mast is lifted to the top, because the outer mast rollers are stationary, the distance between the inner mast rollers and the outer mast rollers will decrease as the mast is lifted. When the mast is not lifted, the distance between the two rollers is the largest. Through measurement, it can be known that the distance at this moment is L3. If the above-mentioned inner mast is lifted by a stroke of S, the distance between the rollers at this moment is (L3-S).

[0122] According to the parameters shown in Table 2, the outer door frame single-side pull seat is subjected to force (The force on the sprocket seat is twice the force on the fork frame hinge) Calculate according to formula (4):

[0123] Formula (4);

[0124] External mast single-side cylinder base load Calculate according to formula (5):

[0125] Formula (5);

[0126] Contact force of single-side roller of inner and outer door frames and Calculate according to formula (6):

[0127] Formula (6);

[0128] The calculation process of the three-level gantry loading force is as follows.

[0129] The interaction force between the fork frame and the inner mast can be calculated by 3D software. The mass of each mast component and the distance from the center of mass to the hinge point can be confirmed by 3D software. Fig.14 The parameters of the various components of the gantry are shown in Table 3.

[0130] Fig.14 A diagram of the hinge point positions of a fork frame body of a three-stage gantry provided in an embodiment of the present application, 1401 represents an upper roller, 1402 represents a middle roller, 1403 represents a lower roller, 1404 represents a sprocket seat, and 1405 represents a hinge point.

[0131] Table 3 Parameters of the third type of gantry components

[0132]

[0133] When the fork frame is lifted by the middle cylinder, the contact relationship between the upper, middle and lower rollers and the inner frame channel steel will change. First, the upper and lower rollers contact the inner frame channel steel. When the fork frame is lifted to the end of the middle cylinder stroke, the upper roller separates from the inner frame channel steel and switches to the middle and lower rollers contacting the inner frame channel steel. Therefore, it is necessary to calculate the force of the rollers on the inner frame channel steel under these two working conditions and measure the roller spacing. The upper and lower roller spacing is L1 and the middle and lower roller spacing is L2.

[0134] According to the parameters shown in Table 3, the force on the sprocket seat on one side (The force on the sprocket seat is twice the force on the fork frame hinge point) Calculate according to formula (7) and formula (8):

[0135] Formula (7);

[0136] Formula (8);

[0137] Indicates the force on the fork hinge point. Indicates that the inner frame pull seat is under force.

[0138] The semi-symmetrical middle cylinder seat of the inner mast bears force Calculate according to formula (9):

[0139] Formula (9);

[0140] Roller force under upper and lower single-sided roller contact condition and Calculate according to formula (10):

[0141] Formula (10);

[0142] Roller force in middle and lower single-side roller contact condition and Calculate according to formula (11):

[0143] Formula (11);

[0144] The interaction force between the inner and middle masts can be calculated by 3D software. The mass of each mast component and the distance from the center of mass to the hinge point can be confirmed by 3D software. Fig.15 The parameters of the various components of the gantry are shown in Table 4. Fig.15 This is a diagram of the position of the inner mast hinge point of a three-stage mast provided in an embodiment of the present application, in which 1501 represents the middle chain wheel seat, 1502 represents the middle mast roller, 1503 represents the inner mast roller, and 1504 represents the hinge point.

[0145] Table 4 Parameters of the fourth type of gantry components

[0146]

[0147] When the inner mast is lifted to the top, because the outer mast rollers are stationary, the distance between the inner and outer mast rollers will decrease as the mast is lifted. When the mast is not lifted, the distance between the two rollers is the largest. Through measurement, it can be known that the distance at this moment is L3. If the inner mast is lifted by a stroke of S, the distance between the rollers at this moment is (L3-S).

[0148] According to the parameters shown in Table 4, the load on the sprocket seat on one side of the outer mast (The force on the middle sprocket seat is twice the force on the inner door frame hinge point) Calculate according to formula (12) and formula (13):

[0149] Formula (12);

[0150] Formula (13);

[0151] Indicates that the inner frame pull seat is under force.

[0152] Contact force of single-side roller of inner and middle mast and Calculate according to formula (6):

[0153] Formula (14);

[0154] The interaction force between the middle and outer masts is determined by 3D software. The mass of each mast component and the distance of the center of mass from the hinge point can be confirmed by 3D software. The location of the hinge point is as follows: Fig.16 The parameters of the various components of the gantry are shown in Table 5. Fig.16 This is a diagram of the position of the hinge point of the middle mast of a three-stage mast provided in an embodiment of the present application, in which 1601 represents the hinge point, 1602 represents the pull seat, 1603 represents the outer mast roller, and 1604 represents the middle mast roller.

[0155] Table 5 Parameters of the fifth type of gantry components

[0156]

[0157] When the inner mast is lifted to the top, because the outer mast rollers are stationary, the distance between the inner and outer mast rollers will decrease as the mast is lifted. When the mast is not lifted, the distance between the two rollers is the largest. Through measurement, it can be known that the distance at this moment is L4. If the inner mast is lifted by a stroke of S´, the distance between the rollers at this moment is (L4-S´).

[0158] According to the parameters shown in Table 5, the outer mast single side cylinder is subjected to force Calculate according to formula (15):

[0159] Formula (15);

[0160] External door frame single side pull seat force Calculate according to formula (16):

[0161] Formula (16);

[0162] External mast single-side cylinder base load Calculate according to formula (17):

[0163] Formula (17);

[0164] Contact force of single-side roller of inner and outer door frames and Calculate according to formula (18):

[0165] Formula (18).

[0166] See also Fig.17 , Fig.17 This is a schematic diagram of the partial structure of the first forklift provided in the embodiment of the present application, and shows a schematic diagram of the positions of the Haversian seat 1701 and the tilt cylinder 1702.

[0167] See also Fig.18 , Fig.18 The schematic diagram of the partial structure of the second forklift provided in the embodiment of the present application, 1801 represents the side cylinder support seat, 1802 represents the limit roller, 1803 represents the lower roller, 1804 represents the upper roller, 1805 represents the middle roller, and 1806 represents the roller shaft. In this embodiment, the side cylinder support seat can be set with a displacement constraint along the Y direction, the limit roller can be set with a displacement constraint along the X direction, a displacement constraint along the Z direction, a rotation constraint around the Y direction, and a rotation constraint around the Z direction, the lower roller can be set with a displacement constraint along the X direction and a rotation constraint around the Z direction, the upper roller can be set with a displacement constraint along the X direction and a rotation constraint around the Z direction, the middle roller can be set with a displacement constraint along the X direction and a rotation constraint around the Z direction, and the roller shaft can be set with a displacement constraint along the Z direction.

[0168] See also Fig.19 , Fig.19 This is a schematic diagram of the partial structure of a third forklift provided in an embodiment of the present application, where 1901 represents a cylinder support seat.

[0169] See also Fig. 20 , Fig. 20 The fourth forklift partial structure diagram provided in the embodiment of the present application, 2001 represents a roller seat, 2002 represents a roller, 2003 represents a chain, 2004 represents a pull rod, 2005 represents an outer mast crossbeam, and the roller is mounted on the shaft of the roller seat. In this embodiment, a lifting side cylinder support can be provided to limit the Y-direction displacement.

[0170] See also Fig.21 , Fig.21 This is a schematic diagram of the partial structure of a fifth forklift provided in an embodiment of the present application, showing a fork frame pulling seat 2101.

[0171] This embodiment adopts a simplified method of gantry splitting, splitting the two-stage gantry into inner and outer gantry, and splitting the three-stage gantry into inner, middle and outer gantry, and then establishes the corresponding relative motion simulation models of the roller and the sub-gantry channel steel. By simplifying the model, the simulation calculation amount is greatly reduced and the simulation efficiency is improved.

[0172] Taking the portal calculation of this embodiment as an example, a workstation with a certain processor is used for calculation. It takes 30 hours to obtain the calculation result of the relative motion simulation model of the roller and channel steel of the three-level portal frame (420,000 grid units), and the convergence is good. The total calculation time of the three sub-models of the inner, middle and outer is about 4 days. If the mechanical energy roller channel steel contact simulation of the whole model without splitting is used, the model will reach 2.4 million grid units, the calculation amount will increase exponentially, the calculation time is expected to be nearly one month, and the nonlinear contact pairs will increase greatly, and the convergence will be greatly reduced.

[0173] This embodiment simulates the whole process of gantry lifting and lowering through the simulation model of the relative motion between the roller and the sub-gantry channel steel, and can obtain the stress change and deformation of the gantry in the whole lifting and lowering process. Compared with the previous method of only calculating the static strength of certain working conditions (gantry lifting to the center or lifting to the top working condition), the simulation analysis method of the present invention obtains more comprehensive stress results. The reliability of the gantry can be improved by analyzing and verifying through the simulation analysis method of the present invention.

[0174] The present embodiment adopts a simplified method of splitting the gantry, which can greatly reduce the amount of calculation compared to overall modeling, and has good convergence, which can greatly improve the simulation efficiency. The present embodiment adopts a simplified method of splitting the gantry, which can overcome the problem that the finite element software cannot model the gantry chain lifting system; although the multi-body dynamics software can establish a chain lifting system, it cannot complete the contact modeling of the roller and the channel steel, and cannot simulate the rolling simulation of the roller on the channel steel when the gantry is lifted. The simulation analysis method of this embodiment can simulate the entire dynamic process of the gantry lifting and lowering. Compared with the analysis method that only calculates the static strength of certain working conditions (gantry lifting in the middle or lifting to the top), the stress results obtained by the analysis method of the present invention are more comprehensive.

[0175] An embodiment of the present application provides a forklift gantry structure strength simulation analysis system, which may include:

[0176] The first modeling module is used to determine all the sub-gantry in the forklift gantry and establish a corresponding sub-gantry model for each of the sub-gantry; wherein the sub-gantry is provided with rollers and channel steels, and the sub-gantry model is a finite element mesh model;

[0177] A second modeling module is used to establish a relative motion simulation model based on the sub-gantry model; wherein the relative motion simulation model is used to simulate the relative motion between the roller and the channel steel during the lifting process of the sub-gantry;

[0178] A boundary condition definition module, used to define the boundary conditions of the relative motion simulation model; wherein the boundary conditions include displacement constraints, forces, contacts and gravity fields;

[0179] An analysis module, used for performing nonlinear contact analysis on the relative motion simulation model to obtain the stress state and deformation state of the sub-gantry model;

[0180] A judgment module is used to generate a simulation analysis result of the forklift portal frame structure strength according to the stress state and the deformation state.

[0181] This embodiment determines all the sub-gantry in the forklift gantry, and establishes a corresponding sub-gantry model for each sub-gantry. Based on the sub-gantry model, this embodiment can establish a relative motion simulation model for simulating the relative motion between the roller and the channel steel during the lifting and lowering process of the sub-gantry, and define the boundary conditions of the relative motion simulation model. By performing nonlinear contact analysis on the relative motion simulation model, the stress state and deformation state of the sub-gantry model can be obtained, and then the structural strength of the forklift gantry can be evaluated. The above process splits and simplifies the forklift gantry, and establishes a relative motion simulation model between the split roller and the sub-gantry channel steel, which greatly reduces the amount of calculation and improves the efficiency of simulation analysis. Therefore, this embodiment can simulate the forklift gantry under the premise of reducing the amount of calculation, and efficiently detect the structural strength of the forklift gantry.

[0182] Furthermore, the process of defining the boundary conditions of the relative motion simulation model by the boundary condition definition module includes: defining corresponding displacement constraints for the roller in the relative motion simulation model; and defining corresponding contacts between the roller and the channel steel in the relative motion simulation model.

[0183] Furthermore, the forklift mast comprises an inner mast and an outer mast, and the inner mast and the outer mast are further provided with chains and oil cylinders;

[0184] Correspondingly, the process of the boundary condition definition module defining the boundary conditions of the relative motion simulation model includes: defining corresponding forces for the chain and the cylinder in the relative motion simulation model; defining the forces corresponding to the variable load curve in the relative motion simulation model; wherein the variable load curve is used to describe the corresponding relationship between the sub-gantry height and the preset load during the sub-gantry lifting process, and the preset load includes the loads of the rollers and the roller seats.

[0185] Furthermore, it also includes:

[0186] The curve generation module is used to calculate the load change information of the roller and the roller seat during the lifting and lowering of the sub-gantry by theoretical mechanics calculation or multi-body dynamic software simulation before defining the force corresponding to the variable load curve in the relative motion simulation model; and is also used to draw the variable load curve according to the load change information.

[0187] Furthermore, it also includes:

[0188] The simplification module is used to simplify the structure corresponding to the cylinder into a beam unit in the relative motion simulation model.

[0189] Furthermore, the process of the first modeling module establishing a corresponding sub-gantry model for each of the sub-gantry includes: establishing a corresponding sub-gantry model for each of the sub-gantry based on a symmetry plane, wherein the sub-gantry is a left-right symmetrical structure, and the sub-gantry model is a finite element mesh model of half of the sub-gantry.

[0190] Furthermore, the process of the judgment module generating the simulation analysis result of the forklift gantry structural strength according to the stress state and the deformation state includes: determining the maximum stress value of the sub-gantry model during the simulation process according to the stress state; determining the maximum deformation amount of the sub-gantry model during the simulation process according to the deformation state; judging whether the maximum stress value is less than the stress threshold and the maximum deformation amount is less than the deformation threshold; if so, generating a simulation analysis result that the structural strength of the forklift gantry meets the preset requirements; if not, generating a simulation analysis result that the structural strength of the forklift gantry does not meet the preset requirements.

[0191] Since the embodiments of the system part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the system part, which will not be repeated here.

[0192] The present application also provides a storage medium on which a computer program is stored, and when the computer program is executed, the steps provided in the above embodiment can be implemented. The storage medium may include: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0193] The present application also provides an electronic device, which may include a memory and a processor, wherein a computer program is stored in the memory, and when the processor calls the computer program in the memory, the steps provided in the above embodiment may be implemented. Of course, the electronic device may also include various network interfaces, power supplies and other components.

[0194] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of this application.

[0195] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

Claims

1. A forklift gantry structural strength simulation analysis method, characterized in that: include: Determine all sub-gantry in the forklift gantry, and establish a corresponding sub-gantry model for each of the sub-gantry; wherein each of the sub-gantry is provided with rollers and channel steels, and the sub-gantry model is a finite element mesh model; A relative motion simulation model is established based on the sub-gantry model; wherein the relative motion simulation model is used to simulate the relative motion between the roller and the channel steel during the lifting process of the sub-gantry; Defining boundary conditions of the relative motion simulation model; wherein the boundary conditions include displacement constraints, forces, contacts and gravity fields; Performing nonlinear contact analysis on the relative motion simulation model to obtain the stress state and deformation state of the sub-gantry model; The forklift portal frame structure strength simulation analysis result is generated according to the stress state and the deformation state.

2. The forklift gantry structural strength simulation analysis method according to claim 1 is characterized in that: Defining the boundary conditions of the relative motion simulation model includes: defining corresponding displacement constraints for the roller in the relative motion simulation model; In the relative motion simulation model, corresponding contacts are defined for the roller and the channel steel.

3. The forklift gantry structural strength simulation analysis method according to claim 2 is characterized in that: The forklift gantry comprises an inner gantry and an outer gantry, and the inner gantry and the outer gantry are further provided with chains and oil cylinders; Accordingly, the boundary conditions of the relative motion simulation model are defined, including: defining corresponding forces for the chain and the cylinder in the relative motion simulation model; The force corresponding to the variable load curve is defined in the relative motion simulation model; wherein the variable load curve is used to describe the corresponding relationship between the height of the sub-gantry and the preset load during the sub-gantry lifting process, and the preset load includes the load of the roller and the roller seat.

4. The forklift gantry structural strength simulation analysis method according to claim 3 is characterized in that: Before defining the force corresponding to the variable load curve in the relative motion simulation model, the method further includes: Calculate the load variation information of the roller and the roller seat during the lifting process of the sub-gantry by means of theoretical mechanics calculation or multi-body dynamic software simulation; The variable load curve is drawn according to the load change information.

5. The forklift gantry structural strength simulation analysis method according to claim 3 is characterized in that: Also includes: In the relative motion simulation model, the structure corresponding to the oil cylinder is simplified into a beam unit.

6. The forklift gantry structural strength simulation analysis method according to claim 1 is characterized in that: A corresponding sub-gantry model is established for each of the sub-gantry, including: A corresponding sub-gantry model is established for each sub-gantry based on the symmetry plane, wherein the sub-gantry is a left-right symmetrical structure, and the sub-gantry model is a finite element mesh model of half of the sub-gantry.

7. The forklift gantry structural strength simulation analysis method according to claim 1, characterized in that: Generating a simulation analysis result of the forklift gantry structure strength according to the stress state and the deformation state includes: Determine the maximum stress value of the sub-gantry model during the simulation according to the stress state; Determine the maximum deformation amount of the sub-gantry model during the simulation process according to the deformation state; Determining whether the maximum stress value is less than a stress threshold and the maximum deformation amount is less than a deformation threshold; If yes, then generate a simulation analysis result that the structural strength of the forklift mast meets the preset requirements; If not, a simulation analysis result is generated indicating that the structural strength of the forklift mast does not meet the preset requirements.

8. A forklift gantry structure strength simulation analysis system, characterized in that: include: The first modeling module is used to determine all the sub-gantry in the forklift gantry and establish a corresponding sub-gantry model for each of the sub-gantry; wherein the sub-gantry is provided with rollers and channel steels, and the sub-gantry model is a finite element mesh model; A second modeling module is used to establish a relative motion simulation model based on the sub-gantry model; wherein the relative motion simulation model is used to simulate the relative motion between the roller and the channel steel during the lifting process of the sub-gantry; A boundary condition definition module, used to define the boundary conditions of the relative motion simulation model; wherein the boundary conditions include displacement constraints, forces, contacts and gravity fields; An analysis module, used for performing nonlinear contact analysis on the relative motion simulation model to obtain the stress state and deformation state of the sub-gantry model; A judgment module is used to generate a simulation analysis result of the forklift portal frame structure strength according to the stress state and the deformation state.

9. An electronic device, characterized in that: It comprises a memory and a processor, wherein the memory stores a computer program, and when the processor calls the computer program in the memory, the steps of the forklift portal frame structure strength simulation analysis method as claimed in any one of claims 1 to 7 are implemented.

10. A storage medium, characterized in that: The storage medium stores computer executable instructions, and when the computer executable instructions are loaded and executed by the processor, the steps of the forklift portal frame structure strength simulation analysis method according to any one of claims 1 to 7 are implemented.

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