Gantry machining center lathe bed design method and lathe bed structure

Abstract

The invention discloses a gantry machining center lathe bed design method and a lathe bed structure. The method comprises the following steps that a finite element analysis model is established; analyzing key working conditions of the lathe bed through a finite element analysis model and extracting a result; topological optimization is carried out according to the extracted result, and a topological optimization result is obtained; and designing the structure of the lathe bed according to an optimization result. By means of the steps, it can be avoided that due to direct superposition of loads of multiple working conditions for analysis, large deformation under one working condition possibly shields small deformation under another working condition, and the accuracy of bed body deformation analysis is improved. The purpose of controlling the rigidity of the lathe bed and the machining precision of the whole machine at the same time can be achieved, the rigidity-weight ratio of the obtained lathe bed structure is high, and the machining precision of the whole machine is effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing, and in particular to a bed design method and bed structure of a gantry machining center. Background Art

[0002] The bed design of the gantry machining center takes into account a variety of factors, including assembly deformation caused by gravity and processing deformation caused by cutting force. If these two working conditions are simply superimposed and analyzed, the larger deformation under one working condition may obscure the smaller deformation under another working condition, thereby affecting the accuracy of the bed deformation analysis; the original bed rigidity is relatively low and the accuracy cannot be accurately controlled. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the existing gantry machining center bed design that comprehensively considers multiple factors, including assembly deformation caused by gravity and machining deformation caused by cutting force. If these two working conditions are simply superimposed and analyzed, the larger deformation under one working condition may obscure the smaller deformation under another working condition, thereby affecting the accuracy of the bed deformation analysis; the original bed has a relatively low rigidity and weight, and cannot accurately control the defect of precision.

[0004] To this end, the present invention provides a method for designing a bed of a gantry machining center, comprising: establishing a finite element analysis model; analyzing the key working conditions of the bed through the finite element analysis model and extracting results; performing topological optimization according to the extracted results and obtaining topological optimization results; performing structural design of the bed according to the optimization results; and verifying the results of the designed bed structure.

[0005] Optionally, the above step of "establishing a finite element analysis model" includes the following steps:

[0006] Determine the model components: The model includes the bed, guide rails, slides, sliders, columns, beams, saddles, rams and spindles;

[0007] Determine boundary conditions: impose fixed constraints on the bottom mounting surface of the bed;

[0008] Determine the connection between components: set fixed constraints on the bottom mounting surface of the bed, the bed and the guide rail are bound together, the guide rail, slider and slide seat are bound together, the slide seat and the column are bound together, the column and the crossbeam are bound together, the crossbeam and the saddle are bound together, and the ram, saddle and spindle are bound together.

[0009] Optionally, the key working conditions in the above step of “analyzing the key working conditions of the bed through the finite element analysis model and extracting the results” include the first key working condition and the second key working condition:

[0010] The first critical working condition is the deformation and load on the bed under the gravity of the components above the bed;

[0011] The second critical working condition is the deformation and stress condition of the bed when the cutting force acts on the spindle end face.

[0012] Optionally, the above step of "analyzing the first critical working condition of the bed through the finite element analysis model and extracting the results" includes the following steps:

[0013] Set the first critical working condition load: apply the standard earth gravity vertically downward. In the first critical working condition, the gravity of the bed itself is not considered, and the material density of the bed is set to 0;

[0014] Extraction of the first critical working condition results: extract the force load of each slider on the bed guide rail, including the X-axis, Y-axis and Z-axis components, and obtain several load values. The maximum load value among the several load values ​​is extracted and recorded as L1; the strain energy of the bed under the first critical working condition load is extracted as U1.

[0015] Optionally, the above step of “analyzing the second critical working condition of the bed through the finite element analysis model and extracting the results” includes the following steps:

[0016] Set the second critical working condition load: move the saddle to the middle position of the beam, move the ram to the lowest position along the Z axis, implement the maximum torque to calculate the components of the cutting force in the X axis, Y axis and Z axis, and apply the cutting force to the spindle end face;

[0017] Extraction of the results of the second critical working condition: extract the load on each slider on the bed guide rail, including the X-, Y-, and Z-axis components, and obtain several load values. The maximum load value among the several load values ​​is extracted and recorded as L2; ​​the strain energy of the bed under the second critical working condition load is extracted as U2.

[0018] Optionally, the load on the slider is a bending moment and a force on the upper surface of the slider.

[0019] Optionally, the above step of “performing topology optimization according to the extracted results and obtaining topology optimization results” includes the following steps:

[0020] Select topology optimization method: Use the topology optimization method of variable density method to remove the material on the non-force transmission path and retain the material on the force transmission path;

[0021] Optimize the topology analysis model: simplify the model under the first and second key working conditions, retain only the bed, and replace the loads of other components on the bed with the extracted loads L1 or L2;

[0022] Topology optimization of the first critical working condition: Load the load L1 extracted from the first critical working condition onto the guide rail surface of the bed in a discrete form;

[0023] Topology optimization of the second critical working condition: Load the load L2 extracted from the second critical working condition onto the guide surface of the bed in a discrete form;

[0024] Optimized area: Fill the inside of the bed with a solid, and the resulting solid structure is used as the optimized area;

[0025] Optimization goal: Minimizing the quality of the optimized area is the goal, and the retained material quality fraction is equal to the optimized bed quality / solid bed quality.

[0026] Optionally, the above step of "verifying the results of the designed bed structure" includes the following steps:

[0027] First critical working condition verification: using the structure designed in step 4, according to the first critical working condition method in step 2, calculate the X-direction deformation, Y-direction deformation and Z-direction deformation of the bed, and verify;

[0028] Verification of the second critical working condition: Using the structure designed in step 4, calculate the X-direction deformation, Y-direction deformation, and Z-direction deformation of the bed according to the second critical working condition method in step 2, and verify them.

[0029] Optionally, the above step of "verifying the results of the designed bed structure" includes the following steps:

[0030] The result meets the requirements and outputs the final result, or

[0031] Repeat step 2 or step 1 until the result meets the requirements and output the final result.

[0032] A bed structure is designed by adopting the above-mentioned gantry machining center bed design method, comprising a bed body and supporting legs, wherein two supporting legs are provided, and the two supporting legs are arranged oppositely on both sides of the bed body; bolt holes are opened on the supporting legs; the bed body and the two supporting legs enclose a cavity;

[0033] Among them, a plurality of reinforcing ribs are provided on the inner side of the cavity and around the bolt hole, and the reinforcing ribs include a first reinforcing rib provided in the cavity, the outer surface of the first reinforcing rib is adapted to the inner wall of the cavity, and a groove is provided at the bottom end of the first reinforcing rib to make the first reinforcing rib U-shaped.

[0034] The technical solution provided by the present invention has the following advantages:

[0035] 1. A design method for the bed of a gantry machining center has solved the above problems. Figure 1The method flow chart shown in the figure includes the following steps: step S1, establishing a finite element analysis model; step S2, analyzing the key working conditions of the bed through the finite element analysis model and extracting the results; step S3, performing topological optimization according to the extracted results and obtaining the topological optimization results; step S4, performing structural design of the bed according to the optimization results; step S5, verifying the results of the designed bed structure. In the design process, by establishing a finite element analysis model and analyzing the key working conditions and extracting the results through the finite element analysis model, the finite element analysis method can be used for structural design, and a complete quantitative design method can be given, which can realize the consideration of the influence of various working condition loads on the bed when designing the gantry machining bed, and prevent the direct superposition of multiple working condition loads for analysis, which may cause a larger deformation under one working condition to cover up a smaller deformation under another working condition, thereby improving the accuracy of the bed deformation analysis. Then, topology optimization is performed based on the analysis results of the extracted various working loads, and the topology optimization results are obtained. On this basis, the structural design of the bed is carried out, and the results are verified. The purpose of simultaneously controlling the bed stiffness and the processing accuracy of the whole machine can be achieved. According to the above method, a gantry machining center bed is designed with a high rigidity-to-weight ratio, and the processing accuracy of the whole machine is effectively controlled.

[0036] 2. The present invention uses the finite element analysis method to carry out structural design, provides a complete quantitative design method, establishes a key working condition analysis model - establishes a topology optimization analysis condition - constructs evaluation indicators - clarifies optimization constraints - topology optimization - parameter optimization - performance verification - iterative optimization, and realizes the quantitative design of the stiffness and precision of the gantry machining center bed. The deformation of the bed caused by the reaction force of the spindle cutting and the assembly deformation are comprehensively considered, and the comprehensive performance of the bed and its weighted performance parameters are constructed and evaluated. After the optimization is completed, verification and iterative optimization are carried out to achieve the purpose of controlling the stiffness of the bed and the processing accuracy of the whole machine at the same time; the constraints and optimization goals of the topology optimization are optimized, so that the optimization results can provide clear guidance for the design of the bed structure. The bed designed by the above method has a high rigidity-to-weight ratio, improves the structural rigidity, reduces the weight, improves the processing accuracy of the machine tool, and can also improve the dynamic performance of the machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A method flow chart of the gantry machining center bed design method provided in the present invention;

[0039] Figure 2 It is a finite element analysis model in the gantry machining center bed design method provided in the present invention;

[0040] Figure 3 It is a force diagram of the first key working condition in the design method of the gantry machining center bed provided in the present invention;

[0041] Figure 4 It is a force diagram of the second key working condition in the design method of the gantry machining center bed provided in the present invention;

[0042] Figure 5 It is a force diagram of the first key working condition of topology optimization in the design method of the gantry machining center bed provided in the present invention;

[0043] Figure 6 It is a force diagram of the second key working condition of topology optimization in the gantry machining center bed design method provided in the present invention;

[0044] Figure 7 It is one of the topological density cloud maps in the gantry machining center bed design method provided in the present invention;

[0045] Figure 8 The second topological density cloud map in the gantry machining center bed design method provided in the present invention;

[0046] Fig. 9 A bottom view of the bed structure provided in the present invention;

[0047] Fig.10 A side inner cross-sectional view of the bed structure provided in the present invention;

[0048] Description of reference numerals:

[0049] 1-bed; 11-bed body; 12-supporting feet;

[0050] 2 – Guide rails;

[0051] 3-sliding seat;

[0052] 4 – pillar;

[0053] 5 – crossbar;

[0054] 6 – Sliding saddle;

[0055] 7 – ram;

[0056] 8 – main axis;

[0057] 9 - First reinforcement rib. DETAILED DESCRIPTION

[0058] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0060] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0062] Example 1

[0063] At present, the design of the bed 1 of the gantry machining center takes into account multiple factors, including assembly deformation caused by gravity and machining deformation caused by cutting force. If these two working conditions are simply superimposed and analyzed, the larger deformation under one working condition may obscure the smaller deformation under another working condition, thereby affecting the accuracy of the deformation analysis of the bed 1; the original bed 1 has a relatively low rigidity and weight, and the accuracy cannot be accurately controlled.

[0064] To this end, this embodiment provides a design method for a gantry machining center bed 1 to solve the above-mentioned problems. Figure 1 The method flow chart shown in FIG. 1 comprises the following steps:

[0065] Step S1, establishing a finite element analysis model;

[0066] Step S2, analyzing the key working conditions of the bed 1 through a finite element analysis model and extracting results;

[0067] Step S3, performing topology optimization according to the extracted results, and obtaining topology optimization results;

[0068] Step S4, performing structural design of the bed 1 according to the optimization result;

[0069] Step S5, verifying the designed bed structure.

[0070] In the design process, by establishing a finite element analysis model, and analyzing and extracting the results of key working conditions through the finite element analysis model, the finite element analysis method can be used for structural design, and a complete quantitative design method can be given, which can realize the consideration of the influence of various working condition loads on the bed 1 when designing the gantry machining bed 1, and prevent the direct superposition of multiple working condition loads for analysis, which may cause the larger deformation under one working condition to cover the smaller deformation under another working condition, thereby improving the accuracy of the deformation analysis of the bed 1. Then, according to the analysis results of the extracted multiple working condition loads, topology optimization is carried out, and the topology optimization results are obtained. On this basis, the structure of the bed 1 is designed, and the results are verified, which can achieve the purpose of controlling the stiffness of the bed 1 and the processing accuracy of the whole machine at the same time. According to the above method, a gantry machining center bed 1 is designed, which has a high rigidity-to-weight ratio and the processing accuracy of the whole machine is effectively controlled.

[0071] Figure 2 It is a finite element analysis model in the design method of the gantry machining center bed 1; in this embodiment, step S1, establishing a finite element analysis model; includes the following sub-steps:

[0072] Determine the model components: the model includes the bed 1, guide rail 2, slide 3, slider, column 4, crossbeam 5, saddle 6, ram 7 and spindle 8;

[0073] Determine the boundary conditions: apply fixed constraints to the bottom mounting surface of bed 1;

[0074] Determine the connection between the components: set a fixed constraint on the bottom mounting surface of the bed 1, the bed 1 and the guide rail 2 are bound together, the guide rail 2, the slider and the slide seat 3 are bound together, the slide seat 3 and the column 4 are bound together, the column 4 and the crossbeam 5 are bound together, the crossbeam 5 and the saddle 6 are bound together, and the ram 7, saddle 6 and spindle 8 are bound together. Among them, the column 4, the crossbeam 5, the saddle 6, the ram 7 and the spindle 8 are all arranged above the slider, and the connection structure between the saddle 6 and the crossbeam 5, including the lead screw nut and the lead screw, is also arranged above the slider. Therefore, when performing a force analysis on the bed 1, the above components can be regarded as a whole. In this embodiment, this whole will be used to analyze the force acting on the bed 1.

[0075] In this embodiment, step S2, the key working conditions of the bed 1 are analyzed through a finite element analysis model and the key working conditions in the extracted results include a first key working condition and a second key working condition: the first key working condition is the deformation and load of the bed 1 under the gravity of the parts above the bed 1; the second key working condition is to analyze the deformation and force of the bed 1 when the cutting force acts on the bed 1.

[0076] Specifically, Figure 3 As shown, Figure 3 This is the first key working condition force diagram in the design method of the gantry machining center bed 1 provided in this embodiment. Figure 4 As shown, Figure 4 It is the force diagram of the second critical working condition in the design method of the gantry machining center bed 1 provided in this embodiment.

[0077] Specifically, step S2.1, analyzing the first critical working condition of the bed 1 through the finite element analysis model and extracting the results specifically includes the following sub-steps:

[0078] Step S2.1.1, setting the first critical working condition load: applying the standard earth gravity vertically downward, ignoring the gravity of the bed 1 itself in the first critical working condition, and setting the material density of the bed 1 to 0;

[0079] Step S2.1.2, extract the results of the first critical working condition: extract the force load of each slider on the guide rail 2 of the bed 1, including the X-axis, Y-axis and Z-axis components, and obtain several load values. The maximum load value among the several load values ​​is extracted and recorded as L1; extract the strain energy of the bed 1 under the first critical working condition load as U1. Figure 3 As shown, A in the figure shows multiple sliders under one of the slide seats 3. When extracting the force load of each slider on the guide rail 2 of the bed 1, it is also necessary to extract the force load on multiple sliders under another slide seat 3.

[0080] Specifically, step S2.2, analyzing the second critical working condition of the bed 1 through the finite element analysis model and extracting the results specifically includes the following sub-steps:

[0081] Step S2.2.1, setting the second critical working condition load: moving the saddle 6 to the middle position of the beam 5, moving the ram 7 to the lowest position along the Z axis, implementing the maximum torque to calculate the components of the cutting force in the X axis, Y axis and Z axis, and applying the cutting force to the end face of the spindle 8;

[0082] Step S2.2.2, extract the results of the second critical working condition: extract the load on each slider on the guide rail 2 of the bed 1, including the X, Y, and Z axis components, and obtain several load values. The maximum load value among the several load values ​​F is extracted and recorded as L2; ​​the strain energy of the bed 1 under the second critical working condition load is extracted as U2. Figure 4 As shown, point B in the figure shows multiple sliders under one of the slide seats 3. When extracting the force load of each slider on the guide rail 2 of the bed 1, it is also necessary to extract the force load on multiple sliders under another slide seat 3.

[0083] The loads on the slider in step S2.1.1 and step S2.2.2 are the bending moment and force on the upper surface of the slider.

[0084] Step S3, performing topology optimization according to the extracted results, and obtaining the topology optimization results specifically includes the following sub-steps:

[0085] Step S3.1, select a topology optimization method: use a topology optimization method of variable density method to remove materials on non-force transmission paths and retain materials on force transmission paths;

[0086] Step S3.2, optimizing the topological analysis model: simplifying the models under the first key working condition and the second key working condition, retaining only the bed 1, and replacing the loads of other components on the bed 1 with the extracted loads L1 or L2;

[0087] Step S3.2.1, topology optimization first key condition: Figure 5 As shown, the load L1 extracted from the first critical working condition is loaded onto the guide rail 2 surface of the bed 1 in a discrete form;

[0088] Step S3.2.2, topology optimization second key condition: Figure 6 As shown, the load L2 extracted from the second critical working condition is loaded onto the surface of the guide rail 2 of the bed 1 in a discrete form;

[0089] Specifically, the discrete form mentioned in step S3.2.1 and step S3.2.2 is that L1 or L2 is used as the load and the entire surface of the guide rail 2 of the bed 1 is used as the force-bearing surface.

[0090] Step S3.3, optimizing area: filling the interior of the bed 1 with a solid body, and the obtained solid structure is used as the optimization area;

[0091] Step S3.4, optimization goal: minimize the mass of the optimization area, and the retained material mass fraction is equal to the mass of the optimized bed 1 / the mass of the solid bed 1.

[0092] Step S4, performing structural design of the bed 1 according to the optimization result;

[0093] Step S4.1: Obtain two topological density cloud maps through step S3, such as Figure 7 and Figure 8 As shown, the structure design of the bed 1 is performed through two topological density cloud maps;

[0094] like Fig. 9 and Fig.10 As shown, the bed 1 includes a bed body 11 and supporting legs 12, two supporting legs 12 are provided, and the two supporting legs 12 are relatively arranged on both sides of the bed body 11; bolt holes are provided on the supporting legs 12; the bed body 11 and the two supporting legs 12 enclose a cavity; a plurality of reinforcing ribs are provided on the inner side of the cavity and around the bolt holes, and the reinforcing ribs include a first reinforcing rib 9 provided in the cavity, and the outer surface of the first reinforcing rib 9 is adapted to the inner wall of the cavity. Specifically, in order to ensure the structural strength of the bed body 11, a plurality of transverse and longitudinal reinforcing ribs are installed below the bed body 11, and the upper surface of the first reinforcing rib 9 should be provided with a plurality of transverse and longitudinal mounting grooves corresponding to the above-mentioned plurality of transverse and longitudinal reinforcing ribs, so as to ensure that the upper surface of the first reinforcing rib 9 is arranged in a fit with the lower surface of the bed body 11. Similarly, the side surface of the first reinforcing rib 9 is arranged corresponding to the inner wall shape of the two supporting members, and no further elaboration is made here. A groove is provided at the bottom end of the first reinforcing rib 9 to make the first reinforcing rib 9 U-shaped. Through the above arrangement, the reinforcing ribs are used to support the structures at both ends, so that the loads at the middle position of the bed 1 and the guide rails 2 on both sides are transferred to the foot. The rigidity of the entire bed structure and the better force transmission path are improved. A second reinforcing rib is set at the position where the bolt hole is opened on the support foot 12 to improve the rigidity at the foot bolt hole.

[0095] Step S5, verifying the results of the designed bed structure includes the following sub-steps:

[0096] Step S5.1, first critical working condition verification: using the structure designed in step S4, calculate the deformation of the bed 1 in the X direction, Y direction and Z direction according to the first critical working condition method in step 2, and verify; the verification in this step can refer to the strain energy U1 extracted in step S2.1.2.

[0097] Step S5.2, second critical working condition verification: using the structure designed in step S4, according to the second critical working condition method in step 2, calculate the X-direction deformation, Y-direction deformation and Z-direction deformation of the bed 1, and verify. The verification in this step can refer to the strain energy U2 extracted in step S2.2.2.

[0098] Through the above steps, if the result meets the requirements and the final result is output, if the result does not meet the requirements, the cause is analyzed to see if it is caused by the optimization settings in step 2. If so, repeat step 2 and reset the parameters in step 2 until the result meets the requirements. If it is not caused by the optimization settings in step 2, repeat step 1 to modify the model components, boundary conditions, and connections between components.

[0099] In this embodiment, the structural design is carried out with the help of finite element analysis method, and a complete quantitative design method is given to establish a key working condition analysis model - establish a topology optimization analysis condition - construct evaluation indicators - clarify optimization constraints - topology optimization - parameter optimization - performance verification - iterative optimization, so as to realize the quantitative design of the stiffness and precision of the gantry machining center bed 1. The deformation and assembly deformation of the bed 1 caused by the reaction force of the spindle 8 cutting are comprehensively considered, and the comprehensive performance and weighted performance parameters of the bed 1 are constructed and evaluated. After the optimization is completed, verification and iterative optimization are carried out to achieve the purpose of controlling the stiffness of the bed 1 and the machining precision of the whole machine at the same time; the constraints and optimization goals of the topology optimization are optimized, so that the optimization results can provide clear guidance for the bed structure design. The bed 1 designed by the above method has a high rigidity-to-weight ratio, improves the structural rigidity, reduces the weight, improves the machining precision of the machine tool, and can also improve the dynamic performance of the machine tool.

[0100] Example 2

[0101] This embodiment provides a bed structure, which is designed by the design method of the gantry machining center bed 1 in embodiment 1. Fig. 9 and Fig.10 As shown, the bed 1 includes a bed body 11 and supporting legs 12, two supporting legs 12 are provided, and the two supporting legs 12 are relatively arranged on both sides of the bed body 11; bolt holes are provided on the supporting legs 12; the bed body 11 and the two supporting legs 12 enclose a cavity; a plurality of reinforcing ribs are provided on the inner side of the cavity and around the bolt holes, and the reinforcing ribs include a first reinforcing rib 9 provided in the cavity, and the outer surface of the first reinforcing rib 9 is adapted to the inner wall of the cavity. Specifically, in order to ensure the structural strength of the bed body 11, a plurality of transverse and longitudinal reinforcing ribs are installed below the bed body 11, and the upper surface of the first reinforcing rib 9 should be provided with a plurality of transverse and longitudinal mounting grooves corresponding to the above-mentioned plurality of transverse and longitudinal reinforcing ribs, so as to ensure that the upper surface of the first reinforcing rib 9 is arranged in a fit with the lower surface of the bed body 11. Similarly, the side surface of the first reinforcing rib 9 is arranged corresponding to the inner wall shape of the two supporting members, and no further elaboration is made here. A groove is provided at the bottom end of the first reinforcing rib 9 to make the first reinforcing rib 9 U-shaped. Through the above arrangement, the reinforcing ribs are used to support the structures at both ends, so that the loads at the middle position of the bed 1 and the guide rails 2 on both sides are transferred to the foot. The rigidity of the entire bed structure and the better force transmission path are improved. A second reinforcing rib is set at the position where the bolt hole is opened on the support foot 12 to improve the rigidity at the foot bolt hole.

[0102] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for designing a bed of a gantry machining center, characterized in that: include: Establish finite element analysis model; Analyze the key working conditions of the bed (1) through a finite element analysis model and extract the results; Perform topology optimization based on the extracted results and obtain topology optimization results; Performing structural design of the bed (1) according to the optimization result; The results of the designed bed (1) structure are verified.

2. The method for designing a gantry machining center bed according to claim 1, characterized in that: The step "Establishing a finite element analysis model" includes the following steps: Determine the model components: the model includes a bed (1), a guide rail (2), a slide seat (3), a slider, a column (4), a crossbeam (5), a saddle (6), a ram (7) and a spindle (8); Determine the boundary conditions: apply fixed constraints to the bottom mounting surface of the bed (1); Determine the connection between the components: set a fixed constraint on the bottom mounting surface of the bed (1); the bed (1) and the guide rail (2) are bound together; the guide rail (2), the slider and the slide seat (3) are bound together; the slide seat (3) and the column (4) are bound together; the column (4) and the crossbeam (5) are bound together; the crossbeam (5) and the saddle (6) are bound together; and the ram (7), the saddle (6) and the spindle (8) are bound together.

3. The method for designing a gantry machining center bed according to claim 2, characterized in that: The key working conditions in the step "analyzing the key working conditions of the bed (1) by means of a finite element analysis model and extracting the results" include a first key working condition and a second key working condition: The first critical working condition is the deformation and load on the bed (1) under the action of gravity of components above the bed (1); The second critical working condition is the deformation and stress condition of the bed (1) when the cutting force on the end face of the spindle (8) acts.

4. The method for designing a gantry machining center bed according to claim 3, characterized in that: The step of "analyzing the first critical working condition of the bed (1) by means of a finite element analysis model and extracting the results" comprises the following steps: Setting the first critical working condition load: applying the standard earth gravity vertically downward, ignoring the gravity of the bed (1) itself in the first critical working condition, and setting the material density of the bed (1) to 0; Extraction of the results of the first critical working condition: extract the force load of each slider on the guide rail (2) of the bed (1), including the X-axis, Y-axis and Z-axis components, obtain a number of load values, extract the maximum load value among the several load values ​​and record it as L1; extract the strain energy of the bed (1) under the first critical working condition load as U1.

5. The method for designing a gantry machining center bed according to claim 3, characterized in that: The step of "analyzing the second critical working condition of the bed (1) by means of a finite element analysis model and extracting the results" comprises the following steps: Setting the second critical working condition load: moving the saddle (6) to the middle position of the beam (5), moving the ram (7) to the lowest position along the Z axis, implementing the maximum torque to calculate the components of the cutting force in the X axis, the Y axis and the Z axis, and applying the cutting force to the end face of the spindle (8); Extraction of the results of the second critical working condition: extract the load on each slider on the guide rail (2) of the bed (1), including the X-, Y-, and Z-axis components, to obtain a number of load values, and extract the maximum load value among the several load values ​​as L2; ​​extract the strain energy of the bed (1) under the second critical working condition load as U2.

6. The method for designing a gantry machining center bed according to claim 4 or 5, characterized in that: The load on the slider is the bending moment and force on the upper surface of the slider.

7. The method for designing a gantry machining center bed according to claim 1, characterized in that: The step of "performing topology optimization according to the extracted results and obtaining topology optimization results" includes the following steps: Select topology optimization method: Use the topology optimization method of variable density method to remove the material on the non-force transmission path and retain the material on the force transmission path; Optimizing the topological analysis model: simplifying the model under the first key working condition and the second key working condition, retaining only the bed (1), and replacing the loads of other components on the bed (1) with the extracted loads L1 or L2; Topology optimization of the first critical working condition: loading the load L1 extracted from the first critical working condition onto the surface of the guide rail (2) of the bed (1) in a discrete form; Topology optimization of the second critical working condition: loading the load L2 extracted from the second critical working condition onto the surface of the guide rail (2) of the bed (1) in a discrete form; Optimization area: Fill the inside of the bed (1) with a solid, and the resulting solid structure is used as the optimization area; Optimization objective: The objective is to minimize the mass of the optimized area, and the mass fraction of the retained material is equal to the mass of the optimized bed (1) / the mass of the solid bed (1).

8. The method for designing a gantry machining center bed according to claim 7, characterized in that: The step of "checking the results of the designed bed (1) structure" includes the following steps: First critical working condition verification: using the structure designed in step 4, according to the first critical working condition method in step 2, calculate the X-direction deformation, Y-direction deformation and Z-direction deformation of the bed (1), and verify; Second critical working condition verification: using the structure designed in step 4, according to the second critical working condition method in step 2, calculate the X-direction deformation, Y-direction deformation and Z-direction deformation of the bed (1), and verify them.

9. The method for designing a gantry machining center bed according to claim 7, characterized in that: The step of "checking the results of the designed bed (1) structure" includes the following steps: The result meets the requirements and outputs the final result, or Repeat step 2 or step 1 until the result meets the requirements and output the final result.

10. A bed structure, designed by using the design method for a gantry machining center bed (1) according to any one of claims 1 to 9, characterized in that: The machine comprises a bed body (11) and supporting legs (12), wherein two supporting legs (12) are provided, and the two supporting legs (12) are arranged oppositely on two sides of the bed body (11); bolt holes are provided on the supporting legs (12); and the bed body (11) and the two supporting legs (12) enclose a cavity; A plurality of reinforcing ribs are provided on the inner side of the cavity and around the bolt hole, and the reinforcing ribs include a first reinforcing rib (9) provided in the cavity, the outer surface of the first reinforcing rib (9) is adapted to the inner wall of the cavity, and a groove is provided at the bottom end of the first reinforcing rib (9) so that the first reinforcing rib (9) is U-shaped.

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