CN117302092A

CN117302092A - Lower protective structure with adjustable height and vehicle

Info

Publication number: CN117302092A
Application number: CN202311313563.1A
Authority: CN
Inventors: 邵阳春; 王郑杰; 孟帅; 周鹤; 毛宏泰; 王志坚; 杨磊
Original assignee: Dongfeng Commercial Vehicle Co Ltd
Current assignee: Dongfeng Commercial Vehicle Co Ltd
Priority date: 2023-10-11
Filing date: 2023-10-11
Publication date: 2023-12-29

Abstract

The invention discloses a lower protection structure with adjustable height and a vehicle, and relates to the field of vehicles. The lower protection piece is connected to the frame below the bumper. The driving piece is connected with the lifting assembly and is used for driving the lifting assembly to drive the lower protection piece to lift relative to the vehicle body structure. In another aspect, a vehicle including the lower guard structure is also provided. Through lifting assembly for body construction goes up and down to adjust the ground clearance of lower guard piece, promote whole car trafficability characteristic, compare in through changing or manual regulation lower guard piece, work efficiency is higher, and is also more convenient, has solved among the prior art protection under special road conditions and has left the current problem of restriction vehicle.

Description

Lower protective structure with adjustable height and vehicle

Technical Field

The invention relates to the technical field of vehicles, in particular to a lower protection structure with adjustable height and a vehicle.

Background

The lower protection assembly is a safety structure measure which is more commonly used in the collision safety of the commercial vehicle so as to prevent the opponent vehicle from penetrating into the bottom of the commercial vehicle during collision, thereby reducing the injury. However, when the vehicle is traveling on a road section with poor road conditions and uneven fluctuation, the traveling of the vehicle is limited by the ground clearance of the under-guard.

Currently, the following two schemes are generally adopted for improving the front under protection of the whole car: the buffer device is added on the basis of the original front lower protection assembly, and the front lower protection is comprehensively protected by utilizing the good anti-collision performance of the buffer device; the other is to use a front lower protection assembly with different sizes and different configurations according to different working conditions, so as to adapt to various working conditions.

The buffer device is added, so that the vehicle damage caused by low trafficability can be avoided, but the buffer device is frequently replaced, the protection capability is limited, the damage risk cannot be thoroughly eliminated, and meanwhile, the frequent replacement of the buffer device increases the engineering cost and is not beneficial to long-time engineering operation; the mode of protecting under before changing can ensure engineering cost, but the in-process of protecting under before changing wastes time very much, leads to work efficiency low, and the structure is complicated, and adaptability is poor, can't be applicable to not unidimensional commercial car.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a lower protection structure with adjustable height and a vehicle so as to solve the problem that the lower protection is away from the limit vehicle in the prior art under special road conditions.

In order to achieve the above purpose, the invention adopts the following technical scheme:

in one aspect, the present application provides a height-adjustable lower guard structure comprising:

a lower guard for connection with the vehicle body structure through the lifting assembly;

and the driving piece is connected with the lifting assembly and is used for driving the lifting assembly to drive the lower protection piece to lift relative to the vehicle body structure.

In some alternative embodiments, the lifting assembly includes:

a vertical beam, one end of which is used for being connected with the vehicle body structure, the other end of which is connected with the lower protection piece, and a rack is arranged on the vertical beam along the vehicle height direction;

and a gear connected to an output end of the driving member, the gear being engaged with the rack.

In some alternative embodiments, two vertical beams are spaced apart in the vehicle width direction.

In some alternative embodiments, the racks are provided on opposite side walls of the two vertical beams, the gears are provided correspondingly, and the driving member includes:

the two ends of the worm are respectively provided with threads;

two worm gears coaxially connected with the gears respectively, wherein the worm gears are matched with the threads of the worm;

and the output end of the driving motor is connected with the worm so as to drive the worm to rotate and drive the two gears to synchronously rotate.

In some alternative embodiments, the worm is sleeved with an intermediate gear, and the output end of the driving motor is provided with a driving gear, and the driving gear is meshed with the intermediate gear.

In some alternative embodiments, the lifting assembly further comprises a guide cylinder for connection to the vehicle body structure, and the vertical beam is slidably received in the guide cylinder.

In some alternative embodiments, the guide cylinder is connected to the vehicle body structure by a mount.

In some alternative embodiments, a plurality of reinforcing ribs are provided between the support and the outer wall of the guide cylinder.

In some alternative embodiments, a guide support is connected below the support, the guide support includes a guide plate and a support plate perpendicular to each other to form an L-shaped structure, the lower guard is located at one side of the guide plate, and the driving member is located above the support plate.

In another aspect, the present application also provides a vehicle comprising any one of the above height-adjustable under-guard structures.

Compared with the prior art, the invention has the advantages that: the lifting assembly is lifted relative to the vehicle body structure, so that the ground clearance of the lower protecting piece is adjusted, the trafficability of the whole vehicle is improved, and when the vehicle needs to pass a special road condition, the lower protecting piece can be lifted to improve the trafficability of the vehicle; or when the vehicle loads goods, the chassis of the vehicle is lowered due to the increase of the dead weight, and the height of the lower protection piece can be lifted through the lifting assembly at the moment so as to ensure the normal running of the vehicle. When the vehicle is running on a normal road section without load, the lower protecting piece is lowered to the conventional height so as to meet the safety requirement, and a driver can directly adjust the lower protecting piece through the driving piece.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic illustration of the connection of the structure of an adjustable lower protective structure to a vehicle body structure according to the present invention;

FIG. 2 is an exploded view of the lower shield structure of FIG. 1;

FIG. 3 is a schematic diagram illustrating the cooperation between the lifting assembly and the driving member in FIG. 2;

FIG. 4 is a schematic view of the reinforcing bar of FIG. 1;

FIG. 5 is a graph showing the CAE crash analysis load bearing capacity of an adjustable lower protective structure according to the present invention.

In the figure: 1. a lower guard; 2. a lifting assembly; 21. a vertical beam; 22. a rack; 23. a gear; 24. a guide cylinder; 25. a support; 251. reinforcing ribs; 26. a mounting plate; 27. a guide support; 271. a guide plate; 272. a support plate; 3. a driving member; 31. a worm; 311. an intermediate gear; 32. a turbine; 33. a driving motor; 331. a drive gear; 332. a housing; 34. a rotating shaft; 4. a vehicle body structure.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

In one aspect, as shown in fig. 1, the present application provides a height-adjustable lower protection structure, which includes a lower protection member 1, a lifting assembly 2, and a driving member 3, wherein the lower protection member 1 is lifted relative to a vehicle body structure 4 by the lifting assembly 2, so as to adjust the ground clearance of the lower protection member 1.

Specifically, the lower guard 1 is attached to the vehicle body structure 4 via the lifting assembly 2. Here, the vehicle body structure 4 refers to a vehicle frame, and the lower guard 1 is attached to the vehicle frame below the bumper. The driving member 3 is connected with the lifting assembly 2, and is used for driving the lifting assembly 2 to drive the lower protection member 1 to lift relative to the vehicle body structure 4.

It can be appreciated that when the driving member 3 works, the lower protecting member 1 is adjusted to be at a height from the ground by the lifting assembly 2, so that the lower protecting member 1 can be lifted to improve the trafficability of the vehicle when the vehicle needs to pass a special road condition; or when the vehicle is loaded with goods, the chassis of the vehicle is lowered due to the increase of the self weight, and the height of the lower guard 1 can be lifted by the lifting assembly 2 at this time to ensure the normal running of the vehicle. When the vehicle is traveling in a non-loaded or normal road section, the lower guard 1 is lowered to a conventional height to meet safety requirements.

Preferably, the power switch of the driving part 3 is located in a carriage so as to facilitate a driver to adjust the ground clearance of the lower protection part 1 at any time according to the vehicle condition and road conditions, thereby improving the trafficability of the whole vehicle, adapting to the complex road conditions of the construction site and ensuring the smooth running on the construction site. Compared with the prior art that a buffer device is added, the vehicle has higher trafficability, the lower protective piece 1 is directly lifted to avoid raised road surface obstacles, and the cost that the buffer device is damaged and needs to be replaced frequently in the use process is also reduced; compared with the lower protection piece which is replaced or manually adjusted, the working efficiency is higher and the operation is more convenient.

In some alternative embodiments, as shown in fig. 2 and 3, the lifting assembly 2 includes a vertical beam 21, a rack 22, and a gear 23, wherein one end of the vertical beam 21 is connected to the vehicle body structure 4, and the other end is connected to the lower guard 1, and the rack 22 is provided on the vertical beam 21 in a vehicle height direction; a gear 23 is connected to the output end of the driving element 3, and the gear 23 is engaged with the rack 22.

It will be appreciated that the vertical beam 21 is disposed vertically in the vehicle height direction so that the lower guard 1 is suspended below the vehicle body structure 4 and set to a height from the ground.

In this example, two vertical beams 21 are provided at intervals in the vehicle width direction, corresponding to the two side members of the vehicle frame, respectively, and the other ends of the two vertical beams 21, which are far from the connection with the vehicle body structure 4, are connected with the lower guard 1 so as to better transmit the bearing capacity of the lower guard 1 when being impacted. The driving piece 3 is also connected to the car body structure 4, when the driving piece 3 works, the gear 23 is driven to rotate, and the vertical beam 21 moves relative to the gear 23 through the engagement of the gear 23 and the rack 22, so that the lower protection piece 1 is driven to lift.

Optionally, each gear 23 is provided with a driving member 3 for driving the two vertical beams 21 up and down relative to the body structure 4. It should be noted that the two driving members 3 must be rotated synchronously and at the same rotation speed, so as to prevent the lower guard 1 from jamming during lifting due to the unsynchronization of the two driving members 3.

In some alternative embodiments, the lifting assembly 2 may also be a hydraulic telescopic rod.

In some alternative embodiments, the racks 22 are provided on opposite side walls of the two vertical beams 21, the gears 23 are correspondingly provided with two, the driving member 3 comprises a worm 31, a turbine 32 and a driving motor 33, and two ends of the worm 31 are respectively provided with threads; two worm gears 32 coaxially connected to the gear 23, respectively, the worm gears 32 being screwed to the worm gears 31; the output end of the driving motor 33 is connected with the worm 31 to drive the worm 31 to rotate and drive the two gears 23 to synchronously rotate.

Specifically, the gear 23 and the worm wheel 32 are both connected to the same rotating shaft 34, when the worm 31 is driven by the driving motor 33 to rotate, the worm 31 drives the worm wheels 32 at two ends of the worm 31 to rotate, the worm wheels 32 synchronously drive the gear 23 to rotate together, and the gear 23 rotates and is meshed with the racks 22 on the corresponding vertical beams 21, so that the two vertical beams 21 can synchronously lift together.

It will be appreciated that the worm 31 is driven to rotate by a driving motor 33, so that the two vertical beams 21 at the two ends of the worm 31 can be driven to rise and fall synchronously. Compared with the arrangement of a driving piece on each vertical beam 21, the synchronous effect is better, the structural arrangement can be reduced, and the cost is reduced. The lifting height of the lower guard 1 can be controlled by controlling the number of turns of the driving motor 33, which is convenient and more accurate.

Through the meshing of worm 31 and turbine 32, change the rotation of worm 31 horizontal rotation axis into turbine 32 longitudinal rotation axis, and guarantee can only be worm 31 drive turbine 32 rotation, and turbine 32 unable reverse drive worm 31 rotation, this unidirectional transmission has guaranteed the automatic locking of lower guard 1 in arbitrary high position, has improved the security of lower guard 1.

In this example, the rotation direction of the output end of the driving motor 33 and the rotation direction of the gear 23 are perpendicular to each other, and the rotation of the output end of the driving motor 33 is converted into the rotation of the gear 23 on both sides in the vehicle width direction by the cooperation of the worm wheel 32 and the worm 31, and then the rotation of the gear 23 is converted into the lifting of the vertical beam 21.

When the rack 22 on the vertical beam 21 is engaged with the gear 23 and the vertical beam 21 is lifted, the vertical beam 21 moves along a set track so that the rack 22 can always maintain the engaged state with the gear 23, and the gear 23 and the rack 22 are prevented from being separated to cause transmission failure.

In some alternative embodiments, the worm 31 is sleeved with an intermediate gear 311, the output end of the driving motor 33 is provided with a driving gear 331, and the driving gear 331 is meshed with the intermediate gear 311.

It will be appreciated that the rotation of the output of the drive motor 33 is translated into rotation of the worm 31 by the intermediate gear 311 and the drive gear 331. In this example, the driving motor 33 is disposed in the middle of the worm 31, and is connected with the worm 31 through the meshing of the intermediate gear 311 and the driving gear 331, so that the worm 31 can be better supported and driven to rotate, and the length of the worm 31 is reduced compared with the case that the end of the worm 31 is directly connected to the output end of the driving motor 33. Meanwhile, when the worm 31 and the driving motor 33 need to be replaced or maintained, the disassembly and the assembly are also facilitated.

In this case, the drive motor 33 is provided with a housing 332, the housing 332 being connected to the vehicle body structure 4, the worm 31 passing through the housing 332 and engaging with a drive gear 331 on the output end of the drive motor 33. The turbine 32 and the gear 23 are fixedly arranged on the mounting plate 26 through the rotating shaft 34, and the mounting plate 26 and the shell 332 are fixed in relative position, so that the driving motor 33 can stably drive the gear 23 to rotate.

In some alternative embodiments, the lifting assembly 2 further comprises a guide cylinder 24 for connecting with the vehicle body structure 4, and the vertical beam 21 is slidably sleeved in the guide cylinder 24.

That is, the guide cylinder 24 serves to restrict the sliding direction of the vertical beam 21 and ensure engagement of the rack 22 on the vertical beam 21 with the gear 23.

In this example, the guide cylinder 24 has a cylindrical structure with an opening at the bottom, and the vertical beam 21 extends into the guide cylinder 24 from the opening and is in plug-in fit with the guide cylinder 24. The side wall of the guide cylinder 24 is provided with a avoidance groove which corresponds to the position of the rack 22 and is matched with the rack 22 in size, and the avoidance groove is used for the gear 23 to be meshed with the rack 22.

In some alternative embodiments, the guide cylinder 24 is connected to the vehicle body structure 4 via a support 25.

In this example, the brackets 25 are provided one for each in the vehicle width direction and fixedly connected to the vehicle frame. The two supports 25 correspond to the positions of the frame rails so as to transfer the bearing force of the lower guard 1 when the lower guard 1 is impacted to the frame and improve the impact strength of the lower guard 1. The housing 332 and the guide tube 24 are connected to the brackets 25 located on either side in the vehicle width direction. The worm 31 passes through the two supports 25 at both ends thereof, and is connected to the vertical beam 21 slidably connected to one side of the support 25. That is, the driving member 3 and the lifting assembly 2 are fixedly connected to the frame through the support 25, so that not only is the compactness and stability of the structure improved, but also the driving member 3 and the lifting assembly 2 are arranged in the vehicle width direction, and the maintenance is facilitated.

In some alternative embodiments, a guiding support 27 is further disposed below the support 25, and the guiding support 27 includes a guiding plate 271 and a supporting plate 272 perpendicular to each other, so as to form an L-shaped structure. The opening of the guide support 27 is directed to the lower guard 1 so that the lower guard 1 is positioned at one side of the guide plate 271 and moves on a plane where the guide plate 271 is positioned, and the housing 332 is placed on the support plate 272.

It will be appreciated that the guide support 27 further increases the stability of the connection of the lower guard mechanism to the vehicle body structure, while also limiting displacement of the lower guard 1 in the horizontal direction.

In some alternative embodiments, as shown in fig. 4, a plurality of ribs 251 are provided between the support 25 and the outer wall of the guide cylinder 24.

It will be appreciated that the reinforcement rib 251 serves to reinforce the connection stability of the support bracket 25 and the guide cylinder 24, and to support and reinforce the lower shield 1 when it is subjected to a front horizontal rearward collision force, ensuring that the legal collision strength requirements are met.

Preferably, the reinforcing ribs 251 have a triangular structure.

In some alternative embodiments, the open end of the guide 24 is further provided with a downwardly extending extension plate, which is connected to the support 25, and the connection is also provided with triangular reinforcing ribs 251.

According to the requirements of front lower protection of commercial vehicles, the lower protection collision needs to meet the targets that the P1 point is more than or equal to 80KN and the P2 point is more than or equal to 160 KN. As shown in FIG. 5, in the height-adjustable lower protection structure, through CAE (ComputerAided Engineering, analysis and calculation in engineering design and analysis simulation) collision analysis, the P1 point bearing capacity is 111.3KN, and the P2 point bearing capacity is 383.2KN, so that the requirement of the legal collision strength can be met.

Therefore, although the lower guard 1 can be lifted in the vehicle height direction and is movably connected with the vehicle body structure 4, the connection stability of the lower guard 1 and the vehicle body structure 4 can be enhanced by the arrangement of the structures such as the shell 332, the guide cylinder 24, the support 25 and the guide support 27, so that the lower guard 1 still has higher bearing capacity when being impacted transversely, the safety performance meets and is higher than the national standard, and the lower guard is suitable for popularization and use.

Specifically, as shown in fig. 1, the lower guard structure includes a lower guard 1, a lifting assembly 2, and a driving member 3. The lower guard 1 is connected to the body structure 4 by a lifting assembly 2, and the lower guard 1 is connected to the frame below the bumper. The driving member 3 is connected with the lifting assembly 2, and is used for driving the lifting assembly 2 to drive the lower protection member 1 to lift relative to the vehicle body structure 4.

In some alternative embodiments, the lifting assembly 2 includes a vertical beam 21, a rack 22, and a gear 23, wherein one end of the vertical beam 21 is connected to the vehicle body structure 4, and the other end is connected to the lower guard 1, and the rack 22 is provided on the vertical beam 21 along the vehicle height direction; a gear 23 is connected to the output end of the driving element 3, and the gear 23 is engaged with the rack 22.

In some alternative embodiments, a plurality of ribs 251 are provided between the support 25 and the outer wall of the guide cylinder 24.

Preferably, the reinforcing ribs 251 have a triangular structure.

Therefore, although the lower guard 1 can be lifted in the vehicle height direction and is movably connected with the vehicle body structure 4, the connection stability of the lower guard 1 and the vehicle body structure 4 can be enhanced by the arrangement of the structures such as the shell 332, the guide cylinder 24, the support 25, the guide support 27, the reinforcing ribs 251 and the like, so that the lower guard 1 still has higher bearing capacity when being impacted transversely, the safety performance meets and is higher than the national standard, and the lower guard is suitable for popularization and use.

The working principle of the embodiment of the application is as follows: when the driving motor 33 is started, the output end of the driving motor 33 is reversed, the intermediate gear 311 engaged with the driving motor is rotated clockwise, and simultaneously, both ends (left side and right side) of the worm 31 are driven to rotate clockwise, the worm wheel 32 engaged with the worm 31 is rotated counterclockwise, and the gear 23 and the worm wheel 32 are rotated counterclockwise synchronously, so that the vertical beam 21 fixed with the rack 22 is driven to move upward, and the height of the lower guard 1 is raised accordingly. Conversely, when the down button is pressed, the height of the lower guard 1 is lowered.

According to the height-adjustable lower protection structure and the vehicle, the lifting assembly 2 is lifted relative to the vehicle body structure 4, so that the ground clearance of the lower protection piece 1 is adjusted, and the trafficability of the whole vehicle is improved; the worm 31 is driven to rotate by a driving motor 33, so that the two vertical beams 21 at the two ends of the worm 31 can be driven to synchronously lift; the worm 31 is meshed with the worm wheel 32, so that the rotation of the transverse rotation shaft of the worm 31 is changed into the rotation of the longitudinal rotation shaft of the worm wheel 32, the worm wheel 32 can only be driven by the worm 31 to rotate, the worm wheel 32 cannot reversely drive the worm 31 to rotate, the unidirectional transmission ensures the automatic locking of the lower protection piece 1 at any height position, and the safety of the lower protection piece 1 is improved; by providing the guide support 27, the connection stability of the lower protection mechanism and the vehicle body structure is further increased, and the displacement of the lower protection member 1 in the horizontal direction is also restricted; through the setting of structures such as casing 332, guide cylinder 24, support 25 and direction support 27, can strengthen the connection stability of lower guard 1 and body structure 4 for lower guard 1 still has higher bearing capacity when receiving horizontal striking, and the security performance satisfies and is higher than national standard, is fit for using widely.

In the description of the present application, it should be noted that the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of description of the present application and simplification of the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

It should be noted that in this application, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely a specific embodiment of the application to enable one skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A height-adjustable lower protective structure, comprising:

a lower guard (1) for connection with a vehicle body structure (4) by means of a lifting assembly (2);

the driving piece (3) is connected with the lifting assembly (2) and is used for driving the lifting assembly (2) to drive the lower protection piece (1) to lift relative to the vehicle body structure (4).

2. The height-adjustable lower guard structure according to claim 1, wherein the lifting assembly (2) comprises:

a vertical beam (21) having one end for connection to the vehicle body structure (4) and the other end for connection to the lower guard (1), and a rack (22) provided on the vertical beam (21) in the vehicle height direction;

and a gear (23) connected to the output end of the driving member (3), wherein the gear (23) is meshed with the rack (22).

3. The height-adjustable lower protection structure according to claim 2, wherein the vertical beams (21) are provided at intervals in the vehicle width direction by two.

4. A height-adjustable lower protective structure according to claim 3, wherein said racks (22) are provided on opposite side walls of two of said vertical beams (21), said gears (23) being provided correspondingly in two, said driving member (3) comprising:

a worm (31) with threads at both ends;

two worm gears (32) coaxially connected with the gears (23), wherein the worm gears (32) are matched with the threads of the worm (31);

and the output end of the driving motor (33) is connected with the worm (31) so as to drive the worm (31) to rotate and drive the two gears (23) to synchronously rotate.

5. The height-adjustable lower protection structure according to claim 4, wherein an intermediate gear (311) is sleeved on the worm (31), a driving gear (331) is arranged at the output end of the driving motor (33), and the driving gear (331) is meshed with the intermediate gear (311).

6. The height-adjustable lower guard structure according to claim 2, wherein the lifting assembly (2) further comprises a guide cylinder (24) for connection with the vehicle body structure (4), the vertical beam (21) being slidably sleeved in the guide cylinder (24).

7. The height-adjustable lower protective structure according to claim 6, characterized in that the guide cylinder (24) is connected to the vehicle body structure (4) via a support (25).

8. The height-adjustable lower guard structure according to claim 7, wherein a plurality of reinforcing ribs (251) are provided between the support (25) and the outer wall of the guide cylinder (24).

9. The height-adjustable lower guard structure according to claim 7, characterized in that a guide support (27) is connected below the support (25), the guide support (27) comprising a guide plate (271) and a support plate (272) perpendicular to each other to form an L-shaped structure, the lower guard (1) being located at one side of the guide plate (271), the driving member (3) being located above the support plate (272).

10. A vehicle comprising a height adjustable under-guard structure according to any one of claims 1-9.