CN111400820B - Method for determining connection point of non-bearing type electric automobile frame, non-bearing type electric automobile frame and electric automobile - Google Patents

Method for determining connection point of non-bearing type electric automobile frame, non-bearing type electric automobile frame and electric automobile Download PDF

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Publication number
CN111400820B
CN111400820B CN201811645896.3A CN201811645896A CN111400820B CN 111400820 B CN111400820 B CN 111400820B CN 201811645896 A CN201811645896 A CN 201811645896A CN 111400820 B CN111400820 B CN 111400820B
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frame
vehicle
connection point
modal
determining
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CN111400820A (en
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穆峰
张葆华
孙喜冬
甄林涛
孙志伟
许占高
李子新
陈立冬
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Great Wall Motor Co Ltd
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Great Wall Motor Co Ltd
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60KARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K1/00Arrangement or mounting of electrical propulsion units
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60KARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K1/00Arrangement or mounting of electrical propulsion units
    • B60K1/04Arrangement or mounting of electrical propulsion units of the electric storage means for propulsion
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D24/00Connections between vehicle body and vehicle frame
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D24/00Connections between vehicle body and vehicle frame
    • B62D24/02Vehicle body, not intended to move relatively to the vehicle frame, and mounted on vibration absorbing mountings, e.g. rubber pads
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/60Other road transportation technologies with climate change mitigation effect
    • Y02T10/70Energy storage systems for electromobility, e.g. batteries

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Body Structure For Vehicles (AREA)

Abstract

The invention provides a method for determining a frame connection point of a non-bearing electric automobile, which is used for determining the position of a frame body connection point on a frame and comprises the steps of establishing a three-dimensional model of a frame structure; importing the established three-dimensional model into finite element processing software to carry out finite element gridding processing and output a grid file; importing the grid file into simulation software, inputting simulation frequency, and simulating a frame modal diagram under the frequency; and using the vehicle frame modal value in the vehicle frame modal graph and using the modal node or the lowest modal position in each region as the position of the connecting point. The invention also provides a non-bearing type automobile frame and an automobile, wherein the connection point is determined by the determination method. The connection point position determined by the determination method can realize large rigid connection between the frame and the vehicle body, realize the strength complementation of the frame and the vehicle body, and the frame and the vehicle body can bear the force as a whole, thereby being beneficial to realizing the weight reduction design of the whole vehicle.

Description

Method for determining connection point of non-bearing type electric automobile frame, non-bearing type electric automobile frame and electric automobile
Technical Field
The invention relates to the technical field of vehicle design and development, in particular to a method for determining a frame connection point of a non-bearing electric vehicle. The invention also relates to a non-bearing type automobile frame for determining the position of the connecting point by the determination method and a non-bearing type automobile with the frame.
Background
In the prior art, the structure of the automobile body is mainly divided into a bearing type body and a non-bearing type body. The load-bearing type vehicle body does not have a chassis structure which can bear external force independently, and only supports all parts by the vehicle body, namely the whole vehicle body is used as a whole without an independent girder design, the vehicle body is mounted on the vehicle body through an auxiliary frame in a hanging mode, and the load of the vehicle body is transmitted to wheels through a hanging device. The load-bearing type vehicle body structure has the advantages of small weight, high vehicle stability, low cost, light weight, low oil consumption, good comfort and the like, but the non-load-bearing type vehicle body structure also has the defects of poor vehicle body rigidity, particularly poor diagonal distortion resistance rigidity and the like.
The non-bearing body is also called as a chassis girder frame, and is provided with an independent girder, namely a frame, and a special chassis stress structure, wherein core components such as an engine, a transmission and the like are arranged on the frame. The frame as a whole is a foundation for supporting the whole vehicle, and the body part for the whole person to sit on is another whole on the whole structure. The frame and the upper vehicle body are mainly connected by suspension, the chassis is lower, the vehicle body part is upper, and the vehicle body only bears the weight of drivers and passengers without considering the auxiliary effect of the vehicle body on the frame bearing.
The non-bearing type vehicle body has the advantages of independent vehicle frame, high chassis strength, good anti-bumping performance, non-uniform stress of the four wheels, and no transmission to the vehicle body, so the deformation of the carriage is small, the stability and the safety are good, and the noise in the carriage is low. However, the non-bearing type body structure also has the disadvantages of being heavy, high in mass center of the automobile and poor in high-speed running stability, and particularly the heavy weight of the non-bearing type body structure causes higher cost of the whole automobile and often high oil consumption when the automobile is used.
With the continuous development of the electrification technology and the gradual shortage of petroleum resources, electric vehicles are gradually moving to the lives of people and are accepted by more and more people, and with the improvement of the living standard of people in China, vehicle types with large space, good stability and good safety, such as SUV vehicle types, are popular with more and more people, so that the electric SUV vehicle types are quietly popular products in the domestic automobile market.
For an electric vehicle, an important standard for measuring the quality of the electric vehicle is the duration of the endurance mileage, and if the electric vehicle wants to obtain a higher endurance mileage, a very important means for pursuing light weight by weight reduction design is not negligible. At this time, for a non-load-bearing electric vehicle model with a frame structure, if a relatively high rigid connection between the frame and the vehicle body can be performed, so that the connection rigidity between the frame and the vehicle body is improved, the strength complementation between the frame and the vehicle body is realized, and the characteristic similar to the load-bearing vehicle body structure is achieved, so that a relatively good whole vehicle weight reduction effect can be obtained.
However, in the prior art, aiming at the connection with great rigidity between the vehicle frame and the vehicle body, how to determine the position of the connecting point of the vehicle frame and the vehicle body becomes a difficult problem, and no report related to the connection is found in the published documents.
Disclosure of Invention
In view of the above, the present invention is directed to a method for determining a connection point of a frame of a non-load-bearing electric vehicle, so as to determine a connection point position on the frame, where a connection with a vehicle body with high rigidity is performed.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method for determining the connection point of a non-bearing electric vehicle frame is used for determining the position of the connection point for connecting the vehicle frame and a vehicle body on the vehicle frame, wherein motors are arranged at least at the rear end of the front end and the rear end of the vehicle frame, a battery pack is fixedly arranged at the middle part of the vehicle frame, the connection points on the vehicle frame are a plurality of connection points which are dispersedly arranged at different areas of the vehicle frame, and the method for determining the position of the connection point comprises the following steps:
s1, establishing a three-dimensional model of a frame structure according to a development design target of a whole vehicle;
s2, importing the established three-dimensional model of the frame structure into finite element processing software, carrying out finite element meshing processing on a three-dimensional model file of the frame structure by using the finite element processing software, and outputting a meshed grid file;
s3, importing the grid file output in the step S2 into modal simulation software, defining a simulation frequency interval, simulating a frame mode of the frame model under a first-order frequency in the frequency interval by using the modal simulation software, and outputting a frame mode diagram under the first-order frequency;
and S4, counting modal values of all positions on the frame in the frame modal graph corresponding to the first-order frequency, and taking the modal nodes or the lowest modal positions in all regions in the frame modal graph under the first-order frequency as the positions of the connection points between the frame and the vehicle body in the region.
Further, the frame structure three-dimensional model can be established through CATIA, UG or Pro/E, the finite element processing software is ANSA or HypermeSh, and the simulation software is NASTRAN or ABAQUS.
Further, the frequency interval is from 1HZ to the fixed frequency of the motor carried by the frame.
Further, the positions of the body connecting points of each frame on the frame are symmetrically arranged relative to the width center line of the frame.
Further, the finite element meshing process in step S2 includes the following steps:
s21, removing redundant geometric figures including points, lines and round corners;
s22, performing a median plane drawing operation, and performing grid division on the median plane;
s23, creating a gridding division file and a quality inspection file to generate a grid, and inspecting the grid quality, correcting errors and poor-quality grids;
s24, separating the grid from the geometric model, deleting the originally imported frame structure model file, creating a welding unit and a rigid node, defining the material thickness and the material properties including the elastic modulus E, the NU Poisson' S ratio and the RHO density, and exporting the grid file.
Further, the simulation in step S3 includes the following steps:
s31, creating a frame model generated by the grid file with the selected and imported attributes, and defining the thickness of the material;
s32, giving the material attribute and the material thickness to the frame model;
s33, creating a simulation environment, and defining a simulation frequency interval;
and S34, the ND calculates the order in the frequency interval, a control guidance calculation link solver is established to carry out corresponding calculation commands, and a simulated first-order vehicle frame modal diagram is derived.
Furthermore, the area of the frame, which can be used as the connecting point between the frame and the vehicle body, at least meets the following conditions: easily the frame shaping does not influence the automobile body molding does benefit to the frame with assemble between the automobile body to and accord with the motorcycle type function definition.
Further, the vehicle type function is defined to be a passenger vehicle or a freight vehicle.
Compared with the prior art, the invention has the following advantages:
the frame connection point determining method is based on the characteristic of small motor vibration, the frame model is simulated, and the mode node or the lowest mode position in each area is used as the connection point position, so that the weakest point of vibration superposition in each area of the frame can be used as the connection point between the frame and the vehicle body, and the connection point is weak in vibration, so that high-rigidity connection between the frame and the vehicle body can be performed, the strength complementation between the frame and the vehicle body is realized, the integral bearing stress of the frame and the vehicle body can be realized, and the effect of weight reduction design of the whole vehicle is facilitated.
Another objective of the present invention is to provide a non-load-bearing type vehicle frame, wherein at least the rear end of the front end and the rear end of the frame is provided with a motor, the middle of the frame is fixedly provided with a battery pack, and the frame is provided with a plurality of connectors for connecting with a vehicle body, the connectors are located at the positions of the connection points between the frame and the vehicle body determined by the above determination method, and the connectors are elastic connectors or rigid connectors.
Further, the elastic connecting piece is suspended.
According to the non-bearing type electric automobile frame, the connecting piece is arranged at the connecting point position determined by the determination method, so that high-rigidity connection between the frame and the automobile body can be realized, the strength between the frame and the automobile body is complementary, the frame and the automobile body can bear stress as a whole, and the whole automobile is lightened.
In addition, the invention also provides a non-bearing type automobile which is provided with the non-bearing type automobile frame.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic structural view of a vehicle frame according to an embodiment of the present invention;
FIG. 2 is a schematic structural view of the front end of the frame according to the embodiment of the present invention;
FIG. 3 is a schematic structural view of the front end of the frame according to the embodiment of the present invention;
FIG. 4 is a schematic structural view of a center portion of the vehicle frame according to an embodiment of the present invention;
FIG. 5 is a schematic structural view of the rear end of the vehicle frame according to the embodiment of the present invention;
in the figure:
1-front end structure, 2-middle structure, 3-back end structure;
101-longitudinal beam, 102-front shock absorber tower, 103-collapse beam, 104-anti-collision beam assembly, 105-water tank mounting frame, 106-supporting beam, 107-shock absorber tower reinforcing bracket, 108-front cross beam, 109-front bottom guard plate, 1010-supporting side beam, 1011-reinforcing beam, 1012-suspension mounting seat and 1013-front motor mounting bracket;
201-battery pack;
301-rear shock absorber tower, 302-rear cross beam, 303-tower top support frame, 304-rear motor mounting bracket, 305-rear anti-collision beam, 306-reinforcing rod, 307-rear bottom guard plate.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
Example one
The embodiment relates to a method for determining a frame connection point of a non-bearing electric automobile, which is used for determining the position of a connection point for connecting a frame and an automobile body on the frame in the non-bearing electric automobile. As a preferred embodiment, the motors are respectively installed at the front end and the rear end of the frame, the battery pack is fixedly installed in the middle of the frame, and the connection points for connecting the frame and the vehicle body on the frame are distributed in a plurality of different areas of the frame, so that the frame and the vehicle body can be stably and reliably connected through the connection at a plurality of different positions, and a complete vehicle body structure is formed.
As for the frame structure of the electric vehicle of the present embodiment, an exemplary structure is shown in fig. 1, and the frame structure integrally includes three parts, namely a front end structure 1, a middle structure 2 and a rear end structure 3, the motors 4 respectively disposed at two ends are respectively located in the front end structure 1 and the rear end structure 3, and the battery pack belongs to a part of the middle structure 2. It should be noted that, except for the front end structure 1 and the rear end structure 3, it is needless to say that the motors may be provided only at the rear end, and the following method for determining the positions of the frame connection points is the same.
Specifically, as shown in fig. 2 and 3 in combination, the front end structure 1 of the vehicle frame of the present embodiment includes side members 101 on both sides, a front shock absorber mounting tower 102 fixedly attached to each side member 101, and a crash beam assembly 104 attached between the front ends of the side members 101 on both sides, a radiator mounting bracket 105 for mounting and fixing a radiator of a vehicle on the rear side of the crash beam assembly 104, and a front cross member 108 disposed below the radiator mounting bracket 105 and attached between the side members 101 on both sides.
Wherein, the crashproof roof beam assembly 104 can be connected with the end of longeron 101 through water tank mounting bracket 105, and crashproof roof beam assembly 104 also preferably adopts two crashproof roof beam bodies that arrange from top to bottom to obtain corresponding to the good protection under the high low-speed collision. The crush beam 103 is further provided between the tank mount 105 and the front absorber tower 102 corresponding to the upper impact beam body, and a suspension mount 1012 is provided on the other side of the front absorber tower 102 with respect to the crush beam 103, so that the force transmission of the crush beam 103 to the side member 101 is realized by the front absorber tower 102 and the suspension mount 1012.
In the front end structure 1 of this embodiment, a supporting edge beam 1010 is further connected between the two ends of the top of the tank mounting bracket 105 and the front absorber towers 102 on the two sides, and a reinforcing beam 1011 is also provided on the inner side of the supporting edge beam 1010 on the two sides and connected between the tank mounting bracket 105 and the front absorber towers 102 on the two sides, and the stability of the tank mounting bracket 105 can be improved by the reinforcing beam 1011. In this embodiment, in order to improve the stability of the arrangement of the two side front absorber towers 102 and improve the structural rigidity of the two side front absorber towers, a absorber tower reinforcing bracket 107 is connected between the tops of the two front absorber towers 102, and a supporting beam 106 is also connected near the bottoms of the two side front absorber towers 102.
In this embodiment, the front motor mounting brackets 1013 are also fixedly connected to the suspension mounting seats 1012 on the two sides, and the motor 4 at the front end structure 1 is fixedly connected between the front motor mounting brackets 1013 on the two sides, so as to directly and fixedly connect with the side stringers 101 on the two sides. Further, a front floor panel 109 fixed to the front cross member 108 is provided between the side members 101 on both sides at the bottom of the front end structure 1. Suspension connecting brackets for connecting swing arms and the like in the front suspension are also arranged on the longitudinal beam 101, and the structure and the arrangement of the suspension connecting brackets can be found in the existing Macpherson suspension arrangement mode, so that the detailed description is omitted.
The middle structure 2 of the vehicle frame of the present embodiment is as shown in fig. 4, and specifically includes longitudinal beams 101 on both sides, and further includes a battery pack 201 directly fixed between the longitudinal beams 101 on both sides. The battery pack 201 is integrally composed of a bottom case and a cover plate covering the bottom case, the longitudinal beams 101 specifically connecting the upper and lower sides can be connected with the bottom case through bolts, a battery module, a battery management module and a cooling module are arranged in the bottom case, and the battery module, the electric field management module and the cooling module can refer to related structures in a power battery in the conventional electric vehicle.
In order to improve the structural strength of the middle structure 2 and to have better longitudinal force transmission performance and side impact performance, in this embodiment, the longitudinal beam 101 at the middle structure 2 has a straight beam body, and a partition arranged along the transverse direction of the frame is configured in the bottom case in the battery pack 201, and two ends of the partition extend to two ends of the bottom case in the width direction so as to be connected with the longitudinal beam 101 through the edge portion of the bottom case, so that a reinforcing rib structure between the longitudinal beams 101 at two sides can be formed. In addition, in terms of arrangement, in this embodiment, the bolts for connecting the bottom case and the longitudinal beams 101 may be arranged corresponding to the end portions of the partitions, that is, the bolts are located on the extension lines of the partitions, so that the purpose of connecting strength between the battery pack 201 and the longitudinal beams 101 can also be achieved.
The rear end structure 3 of the present embodiment is specifically shown in fig. 5, and specifically includes longitudinal beams 101 on both sides, a rear absorber tower 301 connected to the longitudinal beams 101 on both sides, respectively, and a rear cross member 302 and a rear impact beam 305 connected between the longitudinal beams 101 on both sides. In order to improve the structural strength of the rear shock absorber tower 301, a tower top support frame 303 is also arranged on one side of the rear shock absorber tower 301, the tower top support frame 303 is connected between the rear shock absorber tower 301 and the longitudinal beams 101, rear motor mounting brackets 304 are fixedly connected to the tower top support frames 303 on the two sides respectively, and the motor 4 in the rear end structure 3 is connected between the rear motor mounting brackets 304 on the two sides so as to be directly and fixedly connected with the longitudinal beams 101 on the two sides.
In the rear end structure 3, a reinforcing bar 306 is provided behind the rear cross member 302 in a cross arrangement, and a rear floor panel 307 is also fixed to the rear cross member 302. In this embodiment, rear suspension mounting brackets are also disposed on the longitudinal beams 101 on both sides of the rear end structure 3, the rear shock absorber tower 301 and the tower top support frame 304, and the arrangement and structure of these rear suspension mounting brackets can refer to the existing five-link independent suspension structure, which is not described herein again.
Based on the above description of the frame structure, the method for determining the location of the connection point in the present embodiment includes the following steps as a whole. Before the following steps of determining the positions of the connection points are introduced, it should be noted that the establishment of the three-dimensional model of the frame structure can be performed by CATIA, UG or Pro/E, the operation of finite element meshing can be performed by ANSA or HypermeSh, and the modal simulation can be performed by NASTRAN or ABAQUS. In the embodiment, the whole determination method is described by specifically adopting CATIA modeling, ANSA for finite element meshing and NASTRAN for frame modal simulation as an example.
The method for determining the position of the connection point in the embodiment specifically comprises the following steps:
s1, modeling: according to the development and design target of the whole vehicle, a frame structure model is established through CATIA software, namely a three-dimensional model diagram of the frame is drawn, and the established frame structure model is output as a frame structure model file in Stp format;
step S2, gridding treatment step: importing the frame structure model file in the Stp format exported in the step S1 into ANSA software, carrying out finite element meshing on the imported frame model file by using the ANSA software, and outputting a meshed grid file;
s3, simulation: importing the grid file output in the step S2 into NASTRAN software, defining a simulation frequency interval, simulating a frame mode of a frame model at a first-order frequency in the frequency interval by using the NASTRAN software, and outputting a frame mode diagram at the first-order frequency;
s4, analyzing and determining: and counting modal values of each position on the frame in the frame modal graph corresponding to the first-order frequency output by the NASTRAN software, and taking the modal node or the lowest modal position in each area in the frame modal graph under the first-order frequency as the position of the connection point between the frame and the body of the area, thereby obtaining the positions of the connection points between the frame and the body of the frame at different areas on the whole frame.
For the above determining steps, in detail, the basic architecture of the vehicle model determined after the vehicle model pre-research is completed, the design objectives of each part and assembly, and the structural parameters based on the objectives, the architecture and each parameter can realize the establishment of the three-dimensional digifax of the vehicle frame.
The finite element meshing process in step S2 specifically includes the following steps.
Step S21: removing redundant geometric figures containing points, lines and round corners;
step S22: performing a mid-plane extraction operation, and performing mesh division on the mid-plane;
step S23: creating a gridding division file and a quality inspection file to generate a gridding, and inspecting the quality of the gridding, correcting errors and poor-quality gridding;
step S24: separating the grid from the geometric model, deleting the originally imported frame structure model file, creating a welding unit and a rigid node, defining the material thickness and the material properties including the elastic modulus E, the NU Poisson's ratio and the RHO density, and then exporting the processed grid file.
The frame model file after finite element gridding processing is obtained through the step-by-step execution of the steps, and then the frame model file can be introduced into NASTRAN software for modal simulation. In this case, it should be noted that, in the simulation processing of step S3, the frequency range defined in the simulation is specifically 1HZ to the fixed frequency of the motor mounted on the vehicle body frame. The starting frequency 1HZ here is the frequency of the occupants of the car, i.e. the frequency of the human body is generally 1-1.6HZ, so the simulation of the frame mode is performed starting from 1 HZ.
In addition, the simulation process of step S3 in this embodiment also includes the following steps.
Step S31: establishing a frame model generated by a grid file with the selected and imported attributes, and defining the thickness of a material;
step S32: assigning material properties and material thickness to the frame model;
step S33: creating a simulation environment and defining a simulation frequency interval;
step S34: and the ND calculates the order in the frequency interval, creates a control guidance calculation link solver to carry out a corresponding calculation command, and derives a simulated vehicle frame modal diagram under the first-order frequency.
After the vehicle frame modal diagram under the first-order frequency is simulated and output through NASTRAN software, statistical analysis of the first-order modal diagram can be executed to determine the positions of the connecting points in each area. Specifically, taking a certain region as an example, the modal values at various positions in the region have high values and low values, so that the modal values at all positions in the region are summed and counted to find a modal node (i.e., a point where the modal shape coefficient is zero) or a lowest modal position, which is also the position of a connecting point used for connecting the vehicle frame and the vehicle body in the region. Of course, it is possible that the modal nodes or lowest modes occupy a larger area in the entire region, and then the appropriate final position may be determined by combining the initial selection conditions with the initial selection positions described below.
In addition to the above-mentioned specific steps of modeling, gridding, simulation, and statistical analysis to determine the positions of the connection points, it should be considered that the positions of the connection points between the vehicle frame and the vehicle body, which are determined on the vehicle frame, should preferably be symmetrically arranged with respect to the center line of the width of the vehicle frame. Furthermore, the selection of the aforementioned region of the frame in which the connection points can be arranged should also satisfy at least the following condition: easily the frame shaping does not influence the automobile body molding does benefit to the frame with assemble between the automobile body to and accord with the motorcycle type function definition.
The vehicle type function definition includes a passenger vehicle or a cargo vehicle, and the vehicle type function definition is considered because the connection point positions corresponding to different vehicle types and the number of the connection points are different. For example, in the case of passenger cars, since the passenger cars are more comfortable, less vibration and noise of the lower car body are transmitted to the engine room, and the connection points on the frame should be of a resilient structure such as suspension, and the number of connection points is as large as possible. For cargo vehicles, such as pick-up trucks, the rear cargo box requires stability due to the major consideration of load-carrying factors, and the comfort requirement is low, so the attachment points for the rear cargo box portion of the pick-up truck can be directly rigidly attached, such as by bolts, and the attachment points can be selected according to the load-carrying capacity design.
In addition, it should be noted that, in the embodiment, the selection of the area for arranging the connection points on the frame based on the conditions of easy formation of the frame, no influence on the shape of the vehicle body, convenient assembly between the frame and the vehicle body, and conformity with the vehicle type function definition is not necessary for determining the connection point positions of the frame and the vehicle body, that is, when determining the connection point positions, the areas can be arbitrarily specified without considering the above conditions, and the connection point positions of different areas can be finally found by the determination step.
However, it is necessary to preliminarily select an area suitable for arranging the connection point on the vehicle frame through the above conditions, and finally determine a suitable connection point in the determination step combined with the present embodiment, in view of not affecting the vehicle frame structure, not affecting the vehicle body shape, contributing to the improvement of the convenience of the vehicle body and the vehicle frame connection, and effectively reducing the influence of the excitation source on the engine room.
In this embodiment, the positions of the connection points determined on the frame through the above determining steps can be shown as D1-D8 in fig. 1. After determining the positions of the connection points through the determining step of the embodiment, the connection between the vehicle frame and the vehicle body can be performed through an elastic connection structure such as a suspension or a rigid connection structure such as a bolt according to different vehicle types. The connecting points of all the areas are low-modal or node positions of the frame, so that the weakest point of vibration superposition in all the areas of the frame can be used as the connecting point between the frame and the body, the weak vibration of the connecting point can realize high-rigidity connection between the frame and the body, the strength complementation of the frame and the body is realized, the integral bearing stress of the frame and the body can be realized, and the effect of weight reduction design of the whole vehicle is favorably realized.
Example two
The present embodiment relates to a non-load-bearing type vehicle frame, wherein a plurality of connecting members for connecting with a vehicle body are installed on the vehicle frame, each connecting member is located at a connecting point between the vehicle frame and the vehicle body determined by the determining method of the first embodiment, and the connecting members are elastic connecting members or rigid connecting members, and when the elastic connecting members are selected, the elastic connecting members are preferably suspended.
The embodiment also relates to a non-bearing type automobile, and the non-bearing type automobile frame is arranged on the non-bearing type automobile.
According to the non-load-bearing electric vehicle frame and the electric vehicle, the connecting piece is arranged at the connecting point position determined by the determination method in the first embodiment, so that high-rigidity connection between the frame and the vehicle body can be realized, the strength between the frame and the vehicle body is complementary, the frame and the vehicle body can bear stress as a whole, the whole vehicle is beneficial to realizing weight reduction, and the practicability is good.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (11)

1. A method for determining a connection point of a frame of a non-bearing electric vehicle is used for determining the position of a connection point for connecting the frame and a vehicle body on the frame, and is characterized in that: the method for determining the positions of the connection points comprises the following steps:
s1, establishing a three-dimensional model of a frame structure according to a development design target of a whole vehicle;
s2, importing the established three-dimensional model of the frame structure into finite element processing software, carrying out finite element meshing processing on a three-dimensional model file of the frame structure by using the finite element processing software, and outputting a meshed grid file;
s3, importing the grid file output in the step S2 into modal simulation software, inputting a simulation frequency interval, simulating a frame mode of a frame model under a first-order frequency in the frequency interval by using the modal simulation software, and outputting a frame mode graph under the first-order frequency;
and S4, counting modal values of all positions on the frame in the frame modal graph corresponding to the first-order frequency, and taking the modal nodes or the lowest modal positions in all regions in the frame modal graph under the first-order frequency as the positions of the connection points between the frame and the vehicle body in the region.
2. The method for determining the frame connection point of the non-load bearing electric vehicle according to claim 1, wherein: the frame structure three-dimensional model can be established through CATIA, UG or Pro/E, the finite element processing software is ANSA or HypermeSh, and the simulation software is NASTRAN or ABAQUS.
3. The method for determining the frame connection point of the non-load bearing electric vehicle according to claim 1, wherein: the frequency interval is from 1HZ to the fixed frequency of the motor carried by the frame.
4. The method for determining the frame connection point of the non-load bearing electric vehicle according to claim 1, wherein: the positions of the connection points of the vehicle bodies of the frames are symmetrically arranged relative to the width center line of the frames.
5. The method for determining the frame connection point of the non-self-supporting electric vehicle according to claim 1, wherein: the finite element gridding processing in the step S2 comprises the following steps:
s21, removing redundant geometric figures including points, lines and round corners;
s22, performing a median plane drawing operation, and performing grid division on the median plane;
s23, creating a gridding division file and a quality inspection file to generate a grid, and inspecting the grid quality, correcting errors and poor-quality grids;
s24, separating the grid from the geometric model, deleting the originally imported frame structure model file, creating a welding unit and a rigid node, defining the material thickness and the material properties including the elastic modulus E, the NU Poisson' S ratio and the RHO density, and exporting the grid file.
6. The method for determining the frame connection point of the non-self-supporting electric vehicle according to claim 1, wherein: the simulation in step S3 includes the following steps:
s31, creating a frame model generated by the grid file with the selected and imported attributes, and defining the thickness of the material;
s32, giving the material attribute and the material thickness to the frame model;
s33, establishing a simulation environment, and defining a simulation frequency interval;
and S34, the ND calculates the order in the frequency interval, a control guidance calculation link solver is created to carry out corresponding calculation commands, and a simulated first-order vehicle frame modal diagram is derived.
7. The method for determining the frame connection point of the non-self-supporting electric vehicle according to any one of claims 1 to 6, wherein: the area of the frame, which can be used as a connecting point between the frame and the vehicle body, at least meets the following conditions: easily the frame shaping does not influence the automobile body molding does benefit to the frame with assemble between the automobile body to and accord with the motorcycle type function definition.
8. The method for determining the frame connection point of the non-load bearing electric vehicle according to claim 7, wherein: the vehicle type function definition comprises that the vehicle is a passenger vehicle or a freight vehicle.
9. The utility model provides a non-formula electric automobile frame that bears which characterized in that: the front end and the rear end of the frame are provided with motors at least at the rear end, the middle part of the frame is fixedly provided with a battery pack, the frame is provided with a plurality of connecting pieces for connecting with a vehicle body, the connecting pieces are positioned at the connecting points between the frame and the vehicle body determined by the determination method of any one of claims 1 to 8, and the connecting pieces are elastic connecting pieces or rigid connecting pieces.
10. The non-load bearing electric vehicle frame of claim 9, wherein: the elastic connecting piece is suspended.
11. The utility model provides a non-formula electric automobile that bears which characterized in that: the non-vehicular electric vehicle has a non-vehicular electric vehicle frame according to claim 9 or 10.
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