Commercial vehicle double-point front traction structure checking method and commercial vehicle front traction structure

Abstract

The invention relates to a commercial vehicle double-point front traction structure checking method and a commercial vehicle front traction structure, and belongs to the field of vehicle structure design. According to the technical scheme, the commercial vehicle double-point front traction structure checking method comprises the following steps that S1, a traction structure finite element model is established, the traction structure finite element model comprises two frame longitudinal beams, and front traction devices are arranged on the front portions of the two frame longitudinal beams; s2, adding constraint conditions to the finite element model; s3, applying a boundary load to the finite element model, and analyzing the stress of the front traction device; and S4, optimizing the finite element model according to an analysis result. According to the scheme, finite element analysis is adopted, real working conditions of structures such as a traction beam and a frame during towing are simulated by adding constraints, then traction force is simulated and applied, structural checking and optimization are performed on the frame and the front traction device, and the strength performance of the front traction device is ensured in the design stage.

Description

Technical Field

[0001] The invention relates to the field of vehicle structure design, in particular to a commercial vehicle double-point front traction structure verification method and a commercial vehicle front traction structure. Background Art

[0002] Commercial vehicles include freight trucks and buses. The frame structure of freight trucks is significantly different from that of buses and general passenger cars. Freight trucks usually adopt a frame structure with longitudinal and transverse beams, and the vehicle's power system, cab and cargo part are installed on the frame. The traction beam is an indispensable structure for commercial vehicles. When the vehicle loses power and needs to be pulled out of trouble, it can be pulled out of trouble by other vehicles. The traction beam of a commercial vehicle is installed at the front of the frame, usually perpendicular to the longitudinal beam of the frame.

[0003] At present, most commercial vehicles adopt the trailer form of single-point traction, that is, the traction point is located in the middle of the traction beam. It can be seen that during single-point traction, the middle of the traction beam and the two ends connected to the frame longitudinal beam are subjected to tension in opposite directions, which in turn generates a large bending moment on the traction beam, which easily causes deformation of the traction beam.

[0004] Double-point traction can solve the bending moment problem of single-point traction. Specifically, two traction points are set on the traction beam and are located at the two ends of the traction beam, that is, closer to the connection between the frame longitudinal beam, which reduces the distance between the traction force and the reaction force of the frame longitudinal beam. At the same time, the towed vehicle of double-point traction is more stable in the left and right directions.

[0005] During the design phase, the double-point traction structure needs to be checked. Summary of the invention

[0006] Aiming at the problem that a double-point traction structure needs to be calibrated in the design stage, the present invention provides a method for calibrating a double-point front traction structure of a commercial vehicle.

[0007] To achieve the above object, the technical solution adopted by the present invention is a method for verifying the double-point front traction structure of a commercial vehicle, comprising the following steps: S1. Establish a traction structure finite element model, the traction structure finite element model includes two frame longitudinal beams, the front of the two frame longitudinal beams is provided with a front traction device, the front traction device includes a combination bracket respectively fixedly installed at the front end of the two frame longitudinal beams, and a traction beam fixedly installed by the two combination brackets; S2. Add constraints to the finite element model; S3. Apply boundary loads to the finite element model to analyze the stress of the front traction device; S4. Optimize the finite element model based on the analysis results.

[0008] This solution uses finite element analysis to simulate the actual working conditions of the traction beam, frame and other structures when towing by adding constraints, and then simulates the application of traction force to perform structural verification and optimization of the frame and front traction device to ensure the strength performance of the front traction device during the design stage.

[0009] Preferably, the traction structure further includes a rear connecting beam and a front connecting beam, wherein both ends of the rear connecting beam are respectively fixedly connected to the lower rear sides of the two combined brackets, and both ends of the front connecting beam are respectively fixedly connected to the lower front sides of the two combined brackets.

[0010] Preferably, in step S2, the X, Y, Z translational and rotational degrees of freedom of the rear end of the frame are constrained.

[0011] Preferably, in step S3, the boundary load includes a horizontal traction condition and a vertical traction condition, and different conditions are analyzed separately.

[0012] Preferably, the horizontal traction working condition includes: Horizontal oblique traction: Apply traction force F1 at the first end of the traction beam, F1= Fcos(∠a), and apply traction force F2 at the second end of the traction beam, F2= Fcos(∠b); F is the resultant force of F1 and F2, and the direction of F is 50° with the traction beam; Horizontal vertical traction: Apply traction force F3 at the first end of the traction beam, F3= Fcos(∠c), and apply traction force F4 at the second end of the traction beam, F4= Fcos(∠c); F is the resultant force of F3 and F4, and the direction of F is 90° with the traction beam; ∠a, ∠b and ∠c are determined by the length of the traction rope and the traction beam.

[0013] Preferably, the vertical traction working condition includes: Vertical upward traction: Apply traction force F / 2 at both ends of the traction beam, with the direction forming an angle of +6° with the vehicle's forward direction in the vertical plane; Vertical upward traction: Apply traction force F / 2 at both ends of the traction beam, with the direction forming an angle of -6° with the vehicle's forward direction in the vertical plane.

[0014] Set different traction conditions and conduct a comprehensive calibration and analysis of the front traction device.

[0015] Preferred: F=mg / 2 Where: m is the maximum allowable gross mass of a commercial vehicle, in kilograms; g is the acceleration due to gravity, which is 9.8 m / s 2 .

[0016] Preferably, in step S3, the maximum stress of the front traction device does not exceed the tensile strength of its material.

[0017] Preferably, lightweight design is also included: according to the analysis result of step S3, a hollow structure is added or material is removed at a position with low stress, and then re-analysis is performed.

[0018] On the other hand, the present invention also provides a front traction structure for a commercial vehicle, comprising two frame longitudinal beams, combined brackets are respectively installed on the outer sides of the front ends of the two frame longitudinal beams, a traction beam is commonly installed on the front end surfaces of the two combined brackets, both ends of the traction beam are respectively fixedly connected to the two combined brackets, and traction points are provided at both ends of the traction beam; a rear connecting beam and a front connecting beam are also commonly installed on the two combined brackets, both ends of the rear connecting beam are respectively fixedly connected to the lower rear sides of the two combined brackets, and both ends of the front connecting beam are respectively fixedly connected to the lower front sides of the two combined brackets.

[0019] It can be seen from the above technical scheme that the advantages of the present invention are: this scheme adopts a double-point traction beam structure, which can effectively distribute the traction force compared to a single traction beam, so that the front traction beam is more evenly stressed and the stress concentration is reduced; the simulation method used in the optimization process can simulate the traction condition and analyze different traction directions separately, efficiently analyze the stress condition of the front traction beam under various vehicle operating conditions, identify risk points, shorten the development cycle of the front traction beam, and ensure the reliability of the finalized structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0021] Figure 1 It is a structural schematic diagram of the double-point front traction structure in embodiments 1 and 2 of the present invention.

[0022] Figure 2 Schematic diagram of constraint conditions in Embodiment 1 of the present invention.

[0023] Figure 3 Schematic diagram of the traction force under horizontal traction condition in the first embodiment of the present invention Figure 1 .

[0024] Figure 4 Schematic diagram of the traction force under horizontal traction condition in the first embodiment of the present invention Figure 2 .

[0025] Figure 5 It is a schematic diagram of the traction force of the vertical upward traction condition in the first embodiment of the present invention.

[0026] Figure 6 It is a schematic diagram of the traction force of the vertical downward traction condition in the first embodiment of the present invention.

[0027] Description of main reference numerals 1. Frame longitudinal beam, 2. Combined bracket, 3. Traction beam, 4. Traction point, 5. Rear connecting beam, 6. Front connecting beam. DETAILED DESCRIPTION

[0028] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent.

[0029] Embodiment 1 A method for verifying a two-point front traction structure of a commercial vehicle comprises the following steps: S1. Establish Figure 1 The traction structure finite element model shown in the figure includes two frame longitudinal beams, and the front part of the two frame longitudinal beams is provided with a front traction device, and the front traction device includes a combination bracket fixedly installed at the front end of the two frame longitudinal beams, and a traction beam fixedly installed by the two combination brackets; the traction structure also includes a rear connecting beam and a front connecting beam, and the two ends of the rear connecting beam are respectively fixedly connected to the lower rear sides of the two combination brackets, and the two ends of the front connecting beam are respectively fixedly connected to the lower front sides of the two combination brackets; S2. Figure 2 As shown, constraints are added to the finite element model to constrain the X, Y, Z translation and rotation degrees of freedom of the rear end of the frame; S3. Apply boundary loads to the finite element model to analyze the stress of the front traction device. Specifically, the boundary loads include horizontal traction conditions and vertical traction conditions. Different conditions are analyzed separately: Horizontal traction conditions include: Horizontal oblique traction: Apply traction force F1 at the first end of the traction beam, F1= Fcos(∠a), and apply traction force F2 at the second end of the traction beam, F2= Fcos(∠b); the direction of F is 50° with the traction beam; Horizontal vertical traction: Apply traction force F3 at the first end of the traction beam, F3= Fcos(∠c), and apply traction force F4 at the second end of the traction beam, F4= Fcos(∠c); F is the resultant force of F3 and F4, and the direction of F is 90° with the traction beam; In horizontal traction conditions, such as Figure 3 , 4As shown, taking horizontal oblique traction as an example, F is the resultant force of F1 and F2. The reverse extension line of the resultant force passes through the midpoint of the traction beam, that is, the midpoint between the first traction point and the second traction point. ∠a and ∠b pass through the length S of the traction rope ( Figure 4 The sum of the lengths of the two lower hypotenuses of the triangle in the middle) and the length L between the two traction points are determined. S and L are design parameters. After determining the specific values ​​of S and L, ∠a and ∠b can be obtained through trigonometric functions. In the horizontal straight traction condition, the resultant force F is perpendicular to the traction beam. At this time, by analogy Figure 4 , the angles on both sides of F are ∠c (i.e. Figure 4 ∠a and ∠b positions in the graph); Vertical traction conditions include: Vertical upward traction: Figure 5 As shown, a traction force F / 2 is applied to both ends of the traction beam, and the direction forms an angle of +6° with the forward direction of the vehicle in the vertical plane; Vertical upward traction: Figure 6 As shown, a traction force F / 2 is applied to both ends of the traction beam, and the direction forms an angle of -6° with the forward direction of the vehicle in the vertical plane; In the above working conditions, F=mg / 2, where: m is the maximum allowable total mass of the commercial vehicle, in kilograms; g is the acceleration due to gravity, which is 9.8m / s 2 .

[0030] In this step, the maximum stress of the front traction device does not exceed the tensile strength of its material.

[0031] S4. Optimize the finite element model according to the analysis results. Specifically, according to the analysis results of step S3, add a hollow structure or remove material at a location with low stress, and then re-analyze.

[0032] Embodiment 2 A commercial vehicle front traction structure, such as Figure 1 As shown, it includes two frame longitudinal beams 1, and combined brackets 2 are respectively installed on the outer sides of the front ends of the two frame longitudinal beams 1, and a traction beam 3 is commonly installed on the front end surfaces of the two combined brackets 2. The two ends of the traction beam 3 are respectively fixedly connected to the two combined brackets 2, and the two ends of the traction beam 3 are provided with traction points 4; the two combined brackets 2 are also commonly installed with a rear connecting beam 5 and a front connecting beam 6, and the two ends of the rear connecting beam 5 are respectively fixedly connected to the lower rear sides of the two combined brackets, and the two ends of the front connecting beam 6 are respectively fixedly connected to the lower front sides of the two combined brackets.

[0033] It can be seen from the above implementation modes that the beneficial effect of the present invention is that the double-point traction beam structure is adopted in this scheme, which can effectively distribute the traction force compared with the single traction beam, so that the front traction beam is more evenly stressed and the stress concentration is reduced. The simulation method used in the optimization process can simulate the traction condition and analyze different traction directions respectively, so as to efficiently analyze the stress condition of the front traction beam under various vehicle operating conditions, identify risk points, shorten the development cycle of the front traction beam, and ensure the reliability of the finalized structure.

[0034] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for verifying a two-point front traction structure of a commercial vehicle, characterized in that: The following steps are involved: S1. Establish a traction structure finite element model, the traction structure finite element model includes two frame longitudinal beams, the front of the two frame longitudinal beams is provided with a front traction device, the front traction device includes a combination bracket respectively fixedly installed at the front end of the two frame longitudinal beams, and a traction beam fixedly installed by the two combination brackets; S2. Add constraints to the finite element model; S3. Apply boundary loads to the finite element model to analyze the stress of the front traction device; S4. Optimize the finite element model based on the analysis results.

2. The commercial vehicle double-point front traction structure verification method according to claim 1, characterized in that: The traction structure also includes a rear connecting beam and a front connecting beam, wherein two ends of the rear connecting beam are respectively fixedly connected to the lower rear sides of the two combined brackets, and two ends of the front connecting beam are respectively fixedly connected to the lower front sides of the two combined brackets.

3. The commercial vehicle double-point front traction structure verification method according to claim 1, characterized in that: In step S2, the X, Y, Z translational and rotational degrees of freedom of the rear end of the frame are constrained.

4. The commercial vehicle two-point front traction structure verification method according to claim 1, characterized in that: In step S3, the boundary load includes horizontal traction conditions and vertical traction conditions, and different conditions are analyzed separately.

5. The commercial vehicle double-point front traction structure verification method according to claim 4, characterized in that: Horizontal traction conditions include: Horizontal oblique traction: Apply traction force F1 at the first end of the traction beam, F1= Fcos(∠a), and apply traction force F2 at the second end of the traction beam, F2= Fcos(∠b); F is the resultant force of F1 and F2, and the direction of F is 50° with the traction beam; Horizontal vertical traction: Apply traction force F3 at the first end of the traction beam, F3= Fcos(∠c), and apply traction force F4 at the second end of the traction beam, F4= Fcos(∠c); F is the resultant force of F3 and F4, and the direction of F is 90° with the traction beam; ∠a, ∠b and ∠c are determined by the length of the traction rope and the traction beam.

6. The commercial vehicle double-point front traction structure verification method according to claim 4, characterized in that: Vertical traction conditions include: Vertical upward traction: Apply traction force F / 2 at both ends of the traction beam, with the direction forming an angle of +6° with the vehicle's forward direction in the vertical plane; Vertical upward traction: Apply traction force F / 2 at both ends of the traction beam, with the direction forming an angle of -6° with the vehicle's forward direction in the vertical plane.

7. The commercial vehicle two-point front traction structure verification method according to claim 5 or 6, characterized in that: F=mg / 2 Where: m is the maximum allowable gross mass of a commercial vehicle, in kilograms; g is the acceleration due to gravity, which is 9.8 m / s 2 .

8. The commercial vehicle two-point front traction structure verification method according to claim 1, characterized in that: In step S3, the maximum stress of the front traction device does not exceed the tensile strength of its material.

9. The commercial vehicle double-point front traction structure verification method according to claim 1, characterized in that: It also includes lightweight design: according to the analysis results of step S3, hollow structures are added or materials are removed at locations with low stress, and then the analysis is repeated.

10. A commercial vehicle front traction structure, comprising two frame longitudinal beams (1), characterized in that: Combined brackets (2) are respectively installed on the outer sides of the front ends of the two vehicle frame longitudinal beams (1); a traction beam (3) is commonly installed on the front end surfaces of the two combined brackets (2); both ends of the traction beam (3) are respectively fixedly connected to the two combined brackets (2); and traction points (4) are provided at both ends of the traction beam (3); a rear connecting beam (5) and a front connecting beam (6) are also commonly installed on the two combined brackets (2); both ends of the rear connecting beam (5) are respectively fixedly connected to the lower rear sides of the two combined brackets, and both ends of the front connecting beam (6) are respectively fixedly connected to the lower front sides of the two combined brackets.

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