A mounting structure for a commercial vehicle's entry step assembly and a commercial vehicle

Abstract

This invention discloses a mounting structure for a commercial vehicle's upper step assembly, including a cab-end step front mounting bracket assembly, a cab-end step rear mounting bracket assembly, and a chassis-end step mounting bracket assembly. The cab-end step front mounting bracket assembly includes a first main body, which is formed by bending tubing. The chassis-end step mounting bracket assembly includes a second main body, with a first bent pipe connected to one end face of the second main body, and two second bent pipes connected to the same end face. The second main body is fixed to the chassis-end step via a third upper connection point, a third middle connection point, and the second bent pipes are fixed to the chassis-end step via a third lower connection point. This invention improves the connection strength of the step assembly mounting structure while ensuring its performance.

Description

Technical Field

[0001] This invention discloses a mounting structure for a vehicle entry step assembly, which belongs to the field of commercial vehicle technology, specifically a mounting structure for a commercial vehicle entry step assembly. Technical Background

[0002] In existing technology, the entire step assembly mounting structure of commercial vehicles consists of a cab-end step mounting bracket assembly and a chassis-end step mounting bracket assembly. Both the cab-end and chassis-end step mounting bracket assemblies are typically welded and assembled from dozens of large stamped parts (see...). Figure 1 Stamped parts are typically made of 3-4mm thick sheet metal. To maximize the overall strength of the step mounting bracket, most stamped parts are designed with self-overlapping reinforcement structures, resulting in a material utilization rate of less than 42%. Furthermore, due to the complex part structure design and high precision requirements for product fit, the stamping production process for most parts involves more than four steps, and the initial tooling investment is also significant, leading to a high overall production cost. Moreover, in actual application, insufficient overall strength of the step mounting bracket and uneven distribution of mounting points in the step assembly result in inadequate support during stress, causing maximum displacement of some points in the step assembly to exceed 10mm. This reduces the durability of the step assembly, leading to excessive local stress and cracking later on. Therefore, there is an urgent need to invent a new type of onboard step assembly mounting structure that can solve the above-mentioned technical defects without changing the vehicle body mounting points. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings in the technical background and provide a commercial vehicle step assembly mounting structure. This structure, without altering the vehicle body mounting points, reduces the maximum stress value of the step mounting bracket under load by redesigning the step mounting bracket structure and optimizing and evenly distributing the mounting points on the bracket assembly. The newly designed mounting structure is mainly composed of tubing and castings, which improves the assembly connection strength compared to stamped structures. CAE analysis of its structure shows an overall safety factor of over 1.62 and a durability of over 4.56E+06 cycles. Simultaneously, complex large stamped parts are eliminated and replaced with smaller, reinforced stamped structures, resulting in a more compact and rational overall product structure. The overall material utilization rate is increased to over 64%, and each component's manufacturing process is reduced to 2-3 steps. This also facilitates the assembly of the step with the vehicle and the rapid disassembly and replacement of components, saving production costs.

[0004] This application provides a mounting structure for a commercial vehicle's upper step assembly, comprising a front mounting bracket assembly for the cab-end step, a rear mounting bracket assembly for the cab-end step, and a frame-end step mounting bracket assembly for fixing the cab-end floor longitudinal beam and the cab-end step. The front and rear mounting bracket assemblies are located above the frame-end step mounting bracket assembly. The front mounting bracket assembly includes a first main body made of bent tubing with a width-to-length ratio <1:10. The bending direction of the tubing is at a 45° angle to the step mounting surface, and the connection points are parallel to the step mounting surface. The upper end of the first main body is fixed to the cab-end floor longitudinal beam via a connection point, and the first main body is fixed to the cab-end step via a first upper connection point, a first middle connection point, and a first lower connection point. The upper end of the cab-end step rear mounting bracket assembly is fixed to the longitudinal beam of the cab floor via a connection point. The cab-end step rear mounting bracket assembly is fixed to the cab-end step via a second upper connection point, a second middle connection point, and a second lower connection point. The frame-end step mounting bracket assembly includes a second main body. A first bent pipe is connected to one side end face of the second main body. Two second bent pipes are connected to one side end face of the second main body. The second main body is fixed to the frame-end step via a third upper connection point. The second main body is fixed to the frame-end step via a third middle connection point. The second bent pipes are fixed to the frame-end step via a third lower connection point. The first bent pipe is fixed to the frame mounting longitudinal beam. The first bent pipe is located above the second bent pipes. The curvature of the first bent pipe is 45°. The curvature of the second bent pipe is 45°. The first bent pipe and the second bent pipe are at an angle of "". "In terms of structural arrangement, the end of the first bend is connected to a mounting base, and the mounting base is provided with mounting holes arranged in an isosceles triangle. The first bend is fixed to the longitudinal beam of the frame end by bolts connected in the mounting holes. A reinforcing plate is welded between the two second bends. The reinforcing plate is provided with mounting holes, and the reinforcing plate is fixed to the end step of the frame end by bolts connected in the mounting holes."

[0005] In a preferred embodiment of the present invention, the second main body is a reinforced stamped structural component.

[0006] In a preferred embodiment of the present invention, the second main body is provided with positioning and mounting holes for inserting the first bent pipe and the second bent pipe.

[0007] In a preferred embodiment of the present invention, the first bend and the second bend are respectively inserted into the corresponding positioning and mounting holes and then welded and fixed to the second main body.

[0008] In a preferred embodiment of the present invention, the first upper connection point and the second upper connection point are located at the same height, and the first middle connection point and the second middle connection point are located at the same height.

[0009] In a preferred embodiment of the present invention, the distance between the first upper connection point and the first middle connection point is L1, and the distance between the first middle connection point and the first lower connection point is L2, where L1:L2=2:1.

[0010] In a preferred embodiment of the present invention, the distance between the second upper connection point and the second middle connection point is L1, and the distance between the second middle connection point and the second lower connection point is L2, where L1:L2=2:1.

[0011] In a preferred embodiment of the present invention, the distance between the third upper connection point and the third middle connection point is L3, and the distance between the third connection point and the third lower connection point is L4, where L3:L4=2:1.

[0012] In a preferred embodiment of the present invention, the diameter of the first bend is 60 mm and the diameter of the second bend is 45 mm.

[0013] The present invention also discloses a commercial vehicle, which includes a commercial vehicle upper step assembly mounting structure.

[0014] The beneficial technical effects of this invention patent are as follows: This invention has the advantages of simple structure, convenient assembly and good stability. While ensuring its performance, this invention can improve the connection strength of the step assembly mounting structure, greatly simplify the production assembly process and tooling investment, and make it easier to quickly assemble and connect with the step and body, which is in line with the development trend of lean production in automobiles. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the installation structure of the upper step assembly in the prior art;

[0016] Figure 2 This is an assembly diagram of the mounting structure of the upper step assembly for a commercial vehicle according to the present invention;

[0017] Figure 3 This is a schematic diagram of the installation structure of the commercial vehicle upper step assembly according to the present invention;

[0018] Figure 4 This is a schematic diagram of the installation structure of the commercial vehicle upper step assembly according to the present invention;

[0019] Figure 5This is a schematic diagram of the cab-end step front mounting bracket assembly of a commercial vehicle upper step assembly mounting structure according to the present invention;

[0020] Figure 6 This is a schematic diagram of the cab-end step rear mounting bracket assembly of a commercial vehicle upper step assembly mounting structure according to the present invention;

[0021] Figure 7 This is a schematic diagram of the assembly of the vehicle frame end step mounting bracket of the commercial vehicle upper step assembly mounting structure of the present invention;

[0022] Figure 8 This is a schematic diagram of the cab-end step front mounting bracket assembly of a commercial vehicle upper step assembly mounting structure according to the present invention;

[0023] Figure 9 This is a schematic diagram of the vehicle frame end step mounting bracket assembly of the commercial vehicle upper step assembly mounting structure of the present invention;

[0024] Figure 10 This is a schematic diagram of the reinforcing plate of the frame end step mounting bracket assembly of the commercial vehicle upper step assembly mounting structure of the present invention;

[0025] Figure 11 This is a schematic diagram of the mounting base for the reinforcing plate connecting the vehicle frame end step mounting bracket assembly to the vehicle frame end of the present invention, which is a mounting structure for the vehicle step assembly of a commercial vehicle.

[0026] Figure 12 This is a schematic diagram of the reinforcing plate of the cab-end step mounting bracket assembly of a commercial vehicle upper step assembly mounting structure according to the present invention;

[0027] Figure 13 This is a schematic diagram of the reinforcing plate of the frame end step mounting bracket assembly of the commercial vehicle upper step assembly mounting structure of the present invention;

[0028] Figure 14 This is a side view of the reinforcing plate of the vehicle frame end step mounting bracket assembly of the commercial vehicle upper step assembly mounting structure of the present invention. Detailed Implementation

[0029] The technical solutions (including preferred technical solutions) of the present invention will be further described in detail below with reference to the accompanying drawings and by way of listing some optional embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] This invention discloses a mounting structure for a commercial vehicle's upper step assembly, comprising a front mounting bracket assembly A for the cab-end step, a rear mounting bracket assembly B for the cab-end step, and a frame-end step mounting bracket assembly C for fixing the cab-end floor longitudinal beam 1 and the cab-end step 2. The front mounting bracket assembly A and the rear mounting bracket assembly B are located above the frame-end step mounting bracket assembly C. The invention is characterized in that the front mounting bracket assembly A includes a first main body A-1. The first main body A-1 is made of bent tubing with a width-to-length ratio of <1:10. The bending direction of the tubing is at a 45° angle to the step mounting surface, and the connection points of the tubing are parallel to the step mounting surface. The upper end of the first main body A-1 is fixed to the longitudinal beam 1 of the cab floor via a connection point. The first main body A-1 is fixed to the cab-end step 2 via a first upper connection point, a first middle connection point, and a first lower connection point. The upper end of the cab-end step rear mounting bracket assembly B is connected to the cab via a connection point. Floor longitudinal beam 1 is fixedly connected. The cab-end step mounting bracket assembly B is fixedly connected to the cab-end step 2 via a second upper connection point, a second middle connection point, and a second lower connection point. The frame-end step mounting bracket assembly C includes a second main body C-1. A first bent pipe C-2 is connected to one side end face of the second main body C-1, and two second bent pipes C-3 are connected to one side end face of the second main body C-1. The second main body C-1 is fixedly connected to the frame-end step 4 via a third upper connection point. The second main body C-1... The second bend C-3 is fixed to the frame end step 4 via the third connection point, and the first bend C-2 is fixed to the frame mounting longitudinal beam 3. The first bend C-2 is located above the second bend C-3, and the bending arc of the first bend C-2 is 45° (which is beneficial for transmitting the force from the step to the vehicle body through the tube, effectively reducing the influence of bending moment on the length of the tube). The bending arc of the second bend C-3 is also 45°, and the first bend C-2 is located above the second bend C-3 in a " "Structural layout (a reinforcing bracket can be welded onto the stamped part to reduce the stress value at the connection between the stamped part and the pipe. The stamped bracket is designed with an observation hole to facilitate the addition of oil from the adjacent oil pump). The end of the first bend C-2 is connected to the mounting base C-4. The mounting base C-4 is provided with mounting holes arranged in an isosceles triangle. The first bend C-2 is fixed to the longitudinal beam 1 at the end of the frame by bolts connected in the mounting holes. A reinforcing plate C-5 is welded between the two second bends C-3. The reinforcing plate C-5 is provided with mounting holes. The reinforcing plate C-5 is fixed to the step 2 at the end of the cab by bolts connected in the mounting holes."

[0031] It should be noted that the main body of the cab-end step mounting bracket assembly B of the present invention is simplified based on the original stamped part. Its uppermost part is the mounting bracket connected to the longitudinal beam of the cab. The original structure has two mounting brackets connected to the step at the top and middle. When the lower part of the step is under stress, the mounting bracket lacks effective support. The new design adds a welded bracket and a lower bracket connection point at the bottom, forming a parallel arrangement with the mounting points of the front mounting bracket. The original cab step mounting bracket had five connection points at the top and middle. When the lower part of the step is under stress, the entire mounting bracket lacks an effective support transmission path, resulting in local deformation of the step exceeding 10mm in extreme cases. The mounting points of the new design are located on the front and rear sides of the step, and the distance between the mounting points is greater than 75% of the total height of the step. The front and rear mounting brackets form a three-row "ladder-shaped" connection stress-bearing structure. The spacing ratio of the upper, middle, and lower mounting points is designed according to 2:1, which ensures a more uniform stress distribution when the lower part of the step is under stress, effectively reducing the risk of local stress concentration.

[0032] It should be noted that the frame-end step mounting bracket assembly C of the present invention is welded together from tubing and castings. The tubing is connected by stamped parts, and stamped reinforcement brackets are welded locally to reduce the stress limit value at the connection point between the stamped parts and the tubing. Based on the stress boundary conditions, CAE analysis shows that φ60mm tubing is used for the steel pipe connected to the frame, and two φ45mm tubing is used for the step end. There are four mounting points on both sides of the stamped parts (upper and middle), and two mounting points are arranged at the bottom where the stress deformation is greatest, supported by two tubing. The original four mounting points (upper and lower) have been optimized to six mounting points (upper, middle, and lower). The design concept of the frame-end step mounting points is consistent with that of the cab-end mounting points, with three rows of "ladder-shaped" connecting stress-bearing structures. The spacing ratio of the upper, middle, and lower mounting points is still designed according to 2:1.

[0033] The overall step installation structure of this invention has 12 installation points arranged symmetrically on the left and right sides according to the vehicle body and step structure, forming a total of 6 rows of "ladder-shaped" connection structure. The spacing ratio of the upper, middle and lower installation points on the cab and frame ends is designed according to 2:1, which makes the stress distribution more uniform when under force and reduces the risk of excessive local stress.

[0034] This invention, without altering the vehicle body mounting points, reduces the maximum stress value of the step mounting bracket by redesigning its structure and optimizing and evenly distributing the mounting points on the bracket assembly. The newly designed mounting structure is mainly composed of tubing and castings, which improves the assembly connection strength compared to stamped structures. CAE analysis of its structure shows an overall safety factor of over 1.62 and a durability of over 4.56E+06 cycles. Simultaneously, complex large stamped parts are eliminated and replaced with smaller, reinforced stamped structures, resulting in a more compact and rational overall product structure. The overall material utilization rate is increased to over 64%, and each component's manufacturing process is reduced to 2-3 steps. This also facilitates the assembly of the step with the vehicle and the rapid disassembly and replacement of components, saving production costs.

[0035] Preferably, the second main body C-1 is a reinforced stamped structural component.

[0036] Preferably, the second main body C-1 is provided with positioning and mounting holes for inserting the first bent pipe C-2 and the second bent pipe C-3.

[0037] Preferably, the first bend C-2 and the second bend C-3 are respectively inserted into the corresponding positioning and mounting holes and then welded and fixed to the second main body C-1.

[0038] Preferably, the first upper connection point and the second upper connection point are at the same height, and the first middle connection point and the second middle connection point are at the same height.

[0039] Preferably, the distance between the first upper connection point and the first middle connection point is L1, and the distance between the first middle connection point and the first lower connection point is L2, where L1:L2=2:1.

[0040] Preferably, the distance between the second upper connection point and the second middle connection point is L1, and the distance between the second middle connection point and the second lower connection point is L2, where L1:L2=2:1.

[0041] Preferably, the distance between the third upper connection point and the third middle connection point is L3, and the distance between the third connection point and the third lower connection point is L4, where L3:L4=2:1.

[0042] Preferably, the diameter of the first bend C-2 is 60mm and the diameter of the second bend C-3 is 45mm.

[0043] Preferably, the connection between the frame end step mounting assembly and the frame of the present invention adopts a casting structure. The casting and the tube are connected by insertion and then arc welding is used to ensure the stability of the overlap. At the same time, the casting is provided with three mounting holes evenly distributed in an isosceles triangle. It is connected and fixed to the frame by three bolts, which ensures the overall installation and fixing strength of the frame end step.

[0044] Preferably, most of the stamping parts at the pipe connection part of the present invention are designed as U-shaped or similar structures, forming a "mouth" - shaped closed structure with the pipe, and the installation structure strength is better than that of the "L" - shaped bracket.

[0045] The present invention also discloses a commercial vehicle, which includes an installation structure for the upper vehicle step assembly of the commercial vehicle.

[0046] After the implementation of the present invention, without changing the vehicle body mounting points, by redesigning the step mounting bracket structure, optimizing and evenly distributing the mounting points on the bracket assembly, the maximum limit stress value when the step mounting bracket is stressed can be reduced; the main body of the newly designed installation structure is composed of pipes and castings, which improves the connection strength of its assembly compared with the stamping structure. Through the CAE analysis of its structure, the overall safety factor reaches more than 1.62, and the durability reaches more than 4.56E+06 times. At the same time, complex large stamping parts are cancelled and changed to small stamping strengthening structures. The overall structure of the product is more compact and reasonable, the overall material utilization rate is increased to more than 64%, and each sub - part process is also reduced to within 2 - 3 processes. It is also more convenient for the assembly of the step and the whole vehicle and the rapid disassembly and replacement of components, saving production costs.

[0047] The present invention first redistributes and evenly optimizes the mounting points on the step mounting bracket assembly, and overall optimizes the original stamping, welding, and assembly structure into a welding structure composed of pipes, castings, and small stamping brackets. The entire step mounting bracket structure is optimized from 9 original mounting points to 12 mounting points arranged in two columns, forming a 6 - row "ladder - type" connection structure. After the step assembly is stressed, the stress distribution is significantly reduced compared with before. The installation structure of the upper vehicle step assembly is designed as a structural component mainly composed of pipes and castings, and the main structure strength is better than that of the stamping structure; at the same time, small U - shaped stamping brackets are welded on the main structure, and the brackets and the main body form a "mouth" - shaped closed structure, and the installation point structure strength is significantly better than the previous L - shaped bracket; the design structure of the stamping bracket is simple and can be quickly realized by bending with a simple bending die or a bending machine, reducing the investment in complex dies.

[0048] The above are only the preferred embodiments of the present invention and do not limit the present invention. Any modifications, combinations, substitutions, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A mounting structure for a commercial vehicle's upper step assembly, comprising a front mounting bracket assembly (A) for the cab floor longitudinal beam (1) and a rear mounting bracket assembly (B) for the cab end step (2), and a frame end step mounting bracket assembly (C) for fixing the cab floor longitudinal beam (1) and the cab end step (2), wherein the front mounting bracket assembly (A) and the rear mounting bracket assembly (B) are located above the frame end step mounting bracket assembly (C), characterized in that: The cab-end step front mounting bracket assembly (A) includes a first main body (A-1), which is made of bent tubing with a width-to-length ratio of <1:

10. The bending direction of the tubing is at 45° to the step mounting surface, and the connection point of the tubing is parallel to the step mounting surface. The first main body (A-1) is fixed to the cab floor longitudinal beam (1) through a connection point, and the first main body (A-1) is fixed to the cab-end step (2) through a first upper connection point, a first middle connection point, and a first lower connection point. The upper end of the cab-end step rear mounting bracket assembly (B) is fixed to the cab floor longitudinal beam (1) through a connection point, and the cab-end step rear mounting bracket assembly (B) is fixed to the cab-end step (2) through a second upper connection point, a second middle connection point, and a second lower connection point. The frame-end step mounting bracket... The assembly (C) includes a second main body (C-1), a first bent pipe (C-2) connected to one side end face of the second main body (C-1), and two second bent pipes (C-3) connected to one side end face of the second main body (C-1). The second main body (C-1) is fixed to the frame end step (4) via a third upper connection point, the second main body (C-1) is fixed to the frame end step (4) via a third middle connection point, and the second bent pipes (C-3) are fixed to the frame end step (4) via a third lower connection point. The first bent pipe (C-2) is fixed to the frame mounting longitudinal beam (3). The first bent pipe (C-2) is located above the second bent pipes (C-3). The bending arc of the first bent pipe (C-2) is 45°, the bending arc of the second bent pipe (C-3) is 45°, and the first bent pipe (C-2) is located above the second bent pipe (C-3) at an angle of " "In terms of structural arrangement, the end of the first bend (C-2) is connected to a mounting base (C-4), and the mounting base (C-4) is provided with mounting holes arranged in an isosceles triangle. The first bend (C-2) is fixed to the frame mounting longitudinal beam (3) by bolts connected in the mounting holes. A reinforcing plate (C-5) is welded between the two second bends (C-3). The reinforcing plate (C-5) is provided with mounting holes, and the reinforcing plate (C-5) is fixed to the frame end step (4) by bolts connected in the mounting holes." 2. The mounting structure for the commercial vehicle entry step assembly according to claim 1, characterized in that: The second main body (C-1) is a reinforced stamped structural component.

3. The mounting structure for the commercial vehicle entry step assembly according to claim 2, characterized in that: The second main body (C-1) is provided with positioning and mounting holes for inserting the first bent pipe (C-2) and the second bent pipe (C-3).

4. The commercial vehicle entry step assembly mounting structure according to claim 3, characterized in that: The first bend (C-2) and the second bend (C-3) are respectively inserted into the corresponding positioning and mounting holes and then welded and fixed to the second main body (C-1).

5. The mounting structure for the commercial vehicle entry step assembly according to claim 1, characterized in that: The first upper connection point and the second upper connection point are at the same height, and the first middle connection point and the second middle connection point are at the same height.

6. The mounting structure for the commercial vehicle entry step assembly according to claim 5, characterized in that: The distance between the first upper connection point and the first middle connection point is L1, and the distance between the first middle connection point and the first lower connection point is L2, with L1:L2=2:

1.

7. The mounting structure for the commercial vehicle entry step assembly according to claim 5, characterized in that: The distance between the second upper connection point and the second middle connection point is L1, and the distance between the second middle connection point and the second lower connection point is L2, with L1:L2=2:

1.

8. The mounting structure for the commercial vehicle entry step assembly according to claim 1, characterized in that: The distance between the third upper connection point and the third middle connection point is L3, and the distance between the third middle connection point and the third lower connection point is L4, where L3:L4=2:

1.

9. The mounting structure for the commercial vehicle entry step assembly according to claim 1, characterized in that: The diameter of the first bend (C-2) is 60 mm, and the diameter of the second bend (C-3) is 45 mm.

10. A commercial vehicle, characterized in that: Including the commercial vehicle upper step assembly mounting structure as described in any one of claims 1-9.

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