D-pillar lower joint structure and automobile

Abstract

The application discloses a D-column lower joint structure and a car, and relates to the technical field of cars, wherein the D-column lower joint structure comprises a first connecting shell part and a second connecting shell part, the inner side of the first connecting shell part is formed with a first cavity, the first connecting shell part is formed with a first mounting surface corresponding to the inner side of a tail door opening of a sunroof car, the second connecting shell part is arranged in a concave shape, and the concave end opening of the second connecting shell part is connected with the first mounting surface; the technical scheme provided by the application forms a double-cavity connecting structure through the first connecting shell part and the second connecting shell part, the overall structural strength of the first connecting shell part can be improved through the second connecting shell part, in particular, the torsional stiffness and the mode of the first connecting shell part can be effectively improved, and the structure in the scheme can arrange the lower back door lock and the fixing part of the retractor fixing plate on the complete second connecting shell part, and has a great improvement effect on the stiffness and strength of the lower back door lock and the fixing part mounting point of the retractor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobiles, in particular to a D-column lower joint structure and an automobile. BACKGROUND

[0002] With the improvement of people's living standards, automobiles have become the main means of transportation in people's lives. The body stiffness of an automobile is an important measure of the safety of a vehicle. The body frame of an automobile is assembled from multiple independent single frame structures. In order to ensure the overall connection performance between the frames, a joint structure is usually used to fixedly connect two adjacent frame structures.

[0003] In a liftgate automobile, two tailgate structures are generally included. The mounting structure of the two tailgates is mounted on the tail frame structure of the automobile. The tail frame structure of the automobile corresponds to the structural connection between the lower end of the D-column of the automobile body and the lower frame of the tail. A specific joint structure, i.e., a D-column lower joint structure, is generally used to connect the two. The traditional D-column lower joint structure is usually composed of a plate structure or a single-cavity structure formed by a D-column outer plate, a D-column inner plate, and a partition plate. This traditional single-cavity structure can only strengthen the local part of the D-column lower joint structure. The effect of improving the torsional stiffness and modal of the overall frame structure of the automobile body is very limited. The D-column lower joint structure plays a crucial role in the torsional modal and torsional stiffness of the automobile body and the back door modal performance. In particular, it is difficult to improve the back door modal of a vehicle with a liftgate back door. A weak D-column lower joint structure often causes abnormal noise of the automobile body or the back door in the later stage, which is difficult to solve and has a long cycle. SUMMARY

[0004] The main purpose of the present application is to provide a D-column lower joint structure and an automobile, which aims to solve the problem that the traditional D-column lower joint structure has a very limited effect on improving the torsional stiffness and modal of the overall frame structure of the automobile body. In particular, it is difficult to improve the back door modal of a vehicle with a liftgate back door. A weak D-column lower joint structure often causes abnormal noise of the automobile body or the back door in the later stage, which is difficult to solve and has a long cycle.

[0005] To achieve the above purpose, the D-column lower joint structure is applied to a liftgate automobile, and the D-column lower joint structure comprises:

[0006] a first connecting shell portion, which has a first cavity formed on the inner side, and a first mounting surface formed on the inner side of the tailgate opening of the liftgate automobile; and

[0007] a second connecting shell portion, which is concave downward and has a second cavity formed between the second connecting shell portion and the first mounting surface.

[0008] The first connecting shell part comprises a rear wall inner panel left side plate, a tail lamp seat plate and a side wall outer plate, which are sequentially connected to form the first cavity

[0009] The D-column lower joint structure further comprises a rear wall inner panel and a rear wall outer plate.

[0010] The rear wall inner panel left side plate is in an L-shaped structure, comprising a first plate part and a second plate part connected to each other, the first plate part is arranged opposite to the rear wall sealing plate, the second plate part is arranged corresponding to the side wall outer plate, and a side of the second plate part away from the first cavity forms the first mounting surface.

[0011] The second plate part, the side wall outer plate and the tail lamp seat plate are all connected to the rear wall outer plate, and the rear wall inner panel is connected to the second plate part and the rear wall outer plate.

[0012] A rear wall sealing plate is arranged between the rear wall outer plate and the rear wall inner panel left side plate in the first cavity.

[0013] In an embodiment, the first connecting shell part comprises a rear wall inner panel left side plate, a tail lamp seat plate and a side wall outer plate, which are sequentially connected to form the first cavity.

[0014] In an embodiment, the rear wall inner panel left side plate is in an L-shaped structure, comprising a first plate part and a second plate part connected to each other, the first plate part is arranged opposite to the rear wall sealing plate, the second plate part is arranged corresponding to the side wall outer plate, and a side of the second plate part away from the first cavity forms the first mounting surface.

[0015] In an embodiment, the second plate part is arranged in an arc shape, and the lower concave end opening of the second connecting shell part is welded to the arc-shaped first mounting surface.

[0016] In an embodiment, the second connecting shell part is arranged corresponding to the lower end part of the moon roof car's back door.

[0017] A plurality of mounting holes are arranged on the groove bottom of the lower concave groove of the second connecting shell part, the plurality of mounting holes are communicated between the inside and outside of the second cavity, and a back door fixing structure is arranged at the plurality of mounting holes.

[0018] In an embodiment, the back door fixing structure comprises a door lock structure fixing part and a retractor fixing part, and the door lock structure fixing part and the retractor fixing part are respectively fixedly installed at the plurality of mounting holes.

[0019] In an embodiment, the second cavity is provided with a door lock fixing reinforcement plate and a retractor fixing part fixing reinforcement plate corresponding to the positions of the plurality of mounting holes, and the door lock structure fixing part and the retractor fixing part are respectively mounted on the door lock fixing reinforcement plate and the retractor fixing part fixing reinforcement plate.

[0020] The application further provides an automobile comprising the D-pillar lower joint structure.

[0021] a first connecting shell part, an inner side of which is formed with a first cavity, and a first mounting surface corresponding to an inner side of a tail gate opening of the sky-door automobile is formed on the first connecting shell part; and

[0022] a second connecting shell part, which is provided in a concave shape and has a second cavity formed between the second connecting shell part and the first mounting surface.

[0023] The second connecting shell part is arranged corresponding to an end part of a lower back door of the sky-door automobile.

[0024] The D-pillar lower joint structure according to the application comprises a double-cavity connecting structure formed by the first connecting shell part and the second connecting shell part. Specifically, a first connecting end of the first connecting shell part is connected to a lower end of a D-pillar of the automobile, and a second connecting end is connected to a lower frame of a tail gate frame of the automobile. The first connecting shell part is provided in a cavity structure, and an inner side of the first connecting shell part is formed with a first cavity. The cavity structure increases the stress support area of the first connecting shell part, thereby effectively ensuring the strength of the first connecting shell part. In order to further improve the connection performance of the first connecting shell part, a second connecting shell part is arranged on a first mounting surface corresponding to an inner side of a tail gate opening of the sky-door automobile. The second connecting shell part is provided in a concave shape, and a concave end of the second connecting shell part is connected to the first mounting surface. Due to the concave structure, a second cavity is formed between the second connecting shell part and the first mounting surface. The second connecting shell part improves the overall structural strength of the first connecting shell part, and effectively improves the torsional rigidity and modal of the first connecting shell part.

[0025] In addition, the lower back door of the sky-door automobile has a certain load bearing effect, and the rigidity and strength of the mounting points of the lower back door lock and the retractor fixing part are very high. The structure in the application can arrange the door lock and the retractor fixing part fixing reinforcement plate on the complete second connecting shell part. Compared with the traditional mounting and fixing mode, the convenience is greatly improved, and the rigidity and strength of the mounting points of the lower back door lock and the retractor fixing part are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on the drawings shown without any creative effort.

[0027] Figure 1 The structure schematic diagram of the D-pillar lower joint structure corresponding to one side of the vehicle body is provided in the present application.

[0028] Figure 2 The structure schematic diagram of the D-pillar lower joint structure corresponding to one side of the vehicle body is provided in the present application. Figure 1 The partial structure schematic diagram of the D-pillar lower joint structure after being cut at A-A in the present application.

[0029] Figure 3 The structure schematic diagram of the D-pillar lower joint structure corresponding to one side of the vehicle body is provided in the present application. Figure 1 The structure schematic diagram of the D-pillar lower joint structure corresponding to one side of the vehicle body is provided in the present application.

[0030] Figure 4 The back structure schematic diagram of the automobile frame containing the D-pillar lower joint structure in the present application. Figure 1 The back structure schematic diagram of the automobile frame containing the D-pillar lower joint structure in the present application.

[0031] Explanation of the reference signs:

[0032] 100, D-pillar lower joint structure; 1, first connecting shell part; 11, rear wall inner panel left side plate; 111, first plate part; 112, second plate part; 113, first mounting surface; 12, tail lamp seat plate; 13, side wall outer plate; 14, first cavity; 2, second connecting shell part; 21, second cavity; 23, mounting hole; 3, lower back door fixing structure; 31, retractor fixing part; 32, door lock structure fixing part; 33, retractor fixing part fixing reinforcement plate; 34, door lock fixing reinforcement plate; 4, rear wall inner plate; 5, rear wall outer plate; 6, rear wall sealing plate.

[0033] 200, automobile.

[0034] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, and for those skilled in the art, other embodiments can be obtained based on the drawings shown without any creative effort.

[0036] It should be noted that if the embodiments of the present application involve directionality indication (such as up, down, left, right, front, back, etc.), the directionality indication is only used to explain the relative position relationship, motion condition, etc. between components in a certain posture, and if the certain posture changes, the directionality indication also changes accordingly.

[0037] In addition, if the embodiments of the present application involve the description of "first", "second" and the like, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the present application.

[0038] With the improvement of people's living standard, the automobile has become the main traffic tool in people's life process, and the body stiffness of the automobile itself is an important measure of the safety of a car. The body frame of the automobile is assembled by a plurality of independent single frame structures, in order to ensure the overall connection performance between the frames, a joint structure is usually used to connect two adjacent frame structures. In the sky door automobile, two flat opening tail door structures are generally included, and the mounting structure of the two tail doors is mounted on the tail frame structure of the automobile itself. The frame structure of the automobile tail corresponds to the structure connection between the lower end of the D column of the automobile body and the lower frame of the tail, and a specific joint structure is usually used to connect them, that is, the lower joint structure of the D column. The traditional D column lower joint structure is usually composed of a plate structure or a single cavity structure formed by a D column outer plate, a D column inner plate and a partition plate. This traditional single cavity structure can only play a certain reinforcing role in the local part of the D column lower joint structure, and the effect of improving the torsional stiffness and modal of the overall frame structure of the automobile body is very limited. The lower joint structure of the D column plays a crucial role in the torsional modal and torsional stiffness of the automobile body and the back door modal performance, especially for the back door modal of the vehicle with sky back door, which is particularly difficult to improve. The weakness of the D column lower joint structure often causes the later abnormal noise of the automobile body or the back door, which is difficult to solve and has a long cycle.

[0039] The present application provides a D column lower joint structure 100.

[0040] Please refer to Figures 1 to 3In an embodiment of the present application, a D-pillar lower joint structure 100 is disclosed, in a vehicle body frame structure, the entire vehicle body frame is assembled by a plurality of frame structure members, the frame structure member at the vehicle tail position includes the D-pillar structure of the vehicle body frame and the underframe structure at the tail door, and a stable connection relationship needs to be formed between the above two structure members to ensure the integrity and stability of the entire vehicle tail structure frame. In order to further ensure the connection performance between the D-pillar structure of the vehicle body frame and the underframe structure at the tail door, a specific joint structure is generally used to connect between the two, that is, the D-pillar lower joint structure. The traditional D-pillar lower joint structure is usually composed of a plate structure or a single-cavity structure formed by a D-pillar outer plate, a D-pillar inner plate and a partition plate. Such a traditional single-cavity structure can only play a certain reinforcing role in the local part of the D-pillar lower joint structure, and the effect of improving the torsional stiffness and modal is very limited. The D-pillar lower joint structure of the vehicle plays a crucial role in the torsional modal and torsional stiffness of the vehicle body and the back door modal performance, especially for vehicles with a sky door, the back door modal is particularly difficult to improve, and the weak D-pillar lower joint structure often causes abnormal noise of the vehicle body or the back door in the later stage, which is difficult to solve and has a long cycle. Considering the above problems, in the embodiment, the D-pillar lower joint structure of the sky door vehicle is designed and improved to increase the torsional modal and stiffness performance. Specifically, the D-pillar lower joint structure 100 includes a first connection shell part 1 and a second connection shell part 2, wherein the two ends of the first connection shell part 1 are respectively formed with a first connection end and a second connection end, the first connection end corresponds to the lower end of the D-pillar of the vehicle to form a connection, and the second connection end is used to form a connection with the lower frame of the tail door frame of the vehicle. The first connection shell part 1 is provided as a cavity structure, a first cavity 14 is formed on the inner side of the first connection shell part 1, and the stress support area of the entire first shell part is improved by the cavity structure, thereby effectively ensuring the strength of the first shell part. However, a single cavity structure cannot improve the overall modal of the back door of the sky door vehicle, so in the embodiment, a second connection shell part 2 is arranged on the first mounting surface 113 corresponding to the inner side of the tail door opening of the sky door vehicle of the first connection shell part 1, the second connection shell part 2 is arranged in a concave shape, and a fixed connection is formed between the concave end opening of the second connection shell part 2 and the first mounting surface 113. At the same time, due to the arrangement of the above-mentioned concave structure, a second cavity 21 is formed between the second connection shell part 2 and the first mounting surface 113. By arranging the second connection shell part 2, the overall structural strength of the first connection shell part 1 can be improved, especially the torsional stiffness and modal of the first connection shell part 1 can be effectively improved.

[0041] The first connecting shell part 1 comprises a rear wall inner panel left side plate 11, a tail lamp seat plate 12 and a side wall outer plate 13. The rear wall inner panel left side plate 11, the tail lamp seat plate 12 and the side wall outer plate 13 are sequentially connected between horizontal end portions to form a columnar support structure. The first cavity 14 is an internal cavity structure formed after the plate structure is enclosed. In this embodiment, the cavity support structure has multiple support stress surfaces. Compared with a single plate connection mode, the connection performance is greatly improved.

[0042] The rear wall inner panel left side plate 11 is specifically provided in an L-shaped structure and comprises a first plate portion 111 and a second plate portion 112. The first plate portion 111 and the second plate portion 112 are at a certain angle and are integrally formed. The first plate portion 111 is opposite to the rear wall sealing plate 6 corresponding to the outer side of the automobile tail. The side wall outer plate 13 is a structure plate on the outer side of the automobile tail. The second plate portion 112 is arranged corresponding to the side wall outer plate 13, and a side of the second plate portion 112 away from the first cavity 14 forms the first mounting surface 113. The rear wall inner panel left side plate 11 is provided in an L-shaped structure and comprises two structure plate portions. The cavity support structure formed by the rear wall inner panel left side plate 11, the tail lamp seat plate 12 and the side wall outer plate 13 is a four-structure surface support structure. Two plate surfaces are integrally formed and have good integrity. It is also conceivable that the structure plates are connected to each other, and the connection mode is not limited to resistance spot welding and laser welding.

[0043] The second plate portion 112 corresponds to the inner side of the tail opening of the sun and moon door automobile. The joint position is a corner connection position. In order to form a transition surface and improve the overall strength of the corresponding plate, the second plate portion 112 is provided in an arc-shaped structure. The opening edge of the lower concave end opening of the second connecting shell part 2 is also provided in an arc-shaped structure, and the lower concave end opening of the second connecting shell part 2 is welded to the arc-shaped first mounting surface 113. The second connecting shell part 2 can effectively strengthen the first cavity 14.

[0044] The tail door structure of the sky-to-ground door automobile is different from the conventional automobile tail door structure, and the tail door is composed of an upper tail door and a lower tail door which are opened horizontally. The horizontally opened sky-to-ground door structure has been very popular, and generally has the following advantages: first, when taking and placing small items, only the upper door needs to be opened, which is very convenient; second, because the upper and lower doors are opened, the required rear space when opening the door is small, which is convenient for opening and closing the tail door when parking the car close to the wall; third, when driving the off-road vehicle to the wild for play, the lower tail door can be placed down, which is a good resting platform, and the trousers will not be stained with mud on the rear bumper; fourth, compared with the full flip type, the pressure on the roof and hinge will be smaller, which can reduce the deformation of the vehicle compartment. The D-pillar lower joint structure 100 in the scheme corresponds to the position of the lower tail door. Specifically, the second connecting shell part 2 is arranged at the lower back door end part of the sky-to-ground door automobile, and a plurality of mounting holes 23 are arranged at the groove bottom of the lower groove of the second connecting shell part 2, for mounting the lower back door fixing structure 3. In the open state, the lower tail door has a certain load capacity under certain use conditions, so the lower back door fixing structure 3 needs to have good support, so that the horizontally placed lower tail door has good support ability.

[0045] Specifically, the lower back door fixing structure 3 includes a door lock structure fixing part 32 and a retractor fixing part 31, and the door lock structure fixing part 32 and the retractor fixing part 31 are respectively fixed and installed at the plurality of mounting holes 23, and then the corresponding door lock device and retractor device are installed at the corresponding positions, through the above structure, the locking structure and the pulling structure of the lower tail door can be arranged at the two end positions of the lower tail door, and the door lock structure fixing part 32 is arranged at the two end positions of the lower back door, compared with the conventional arrangement of the door lock structure fixing part 32 at the middle position of the lower tail door, the flatness of the support surface of the lower back door structure is guaranteed, and the taking and placing of items is more convenient.

[0046] Meanwhile, the door lock fixing plate 34 and the retractor fixing plate 33 are arranged in the second cavity 21 corresponding to the positions of the mounting holes 23, the door lock structure fixing plate 32 and the retractor fixing plate 31 are respectively arranged on the door lock fixing plate 34 and the retractor fixing plate 33, and the door lock structure fixing plate 32 and the retractor fixing plate 31 are arranged on the second connecting shell 2 through the door lock fixing plate 34 and the retractor fixing plate 33, so that the door lock structure fixing plate 32 and the retractor fixing plate 31 can be arranged on the second connecting shell 2, and the door lock structure fixing plate 32 and the retractor fixing plate 31 are respectively arranged on the corresponding fixing plates, compared with the traditional mounting and fixing mode, the above mode not only greatly improves the convenience, but also greatly improves the rigidity and strength of the mounting points of the door lock structure fixing plate 32 and the retractor fixing plate 31, especially for the top-hinged door structure vehicle, the mounting stability of the lower back door structure can improve the overall stability of the entire door structure to a certain extent.

[0047] The D-pillar lower joint structure 100 further comprises a rear wall inner panel 4 and a rear wall outer panel 5, the rear wall inner panel 4 and the rear wall outer panel 5 correspond to the second connecting end, as shown in Figure 1 and Figure 2 The second plate part 112, the side wall outer panel 14 and the tail lamp seat plate 12 are connected with the rear wall outer panel 5, and the rear wall inner panel 4 is connected with the second plate part 112 and the rear wall outer panel 5, as shown in the drawings, the rear wall outer panel 5 connects a plurality of plate structures at one end of the second connecting end, and the rear wall outer panel 5 is a special-shaped structure, the second plate part 112, the side wall outer panel 14 and the tail lamp seat plate 12 are respectively arranged at different plate end positions of the rear wall outer panel 5, so as to further connect and fix one end of the first connecting shell 1 formed by the above plate structures, and the rear wall inner panel 4 is connected with the second plate part 112 and the rear wall outer panel 5, so as to extend the cavity structure of the second connecting end and strengthen the overall structural strength of the first connecting shell 1.

[0048] In order to further improve the stability of the first cavity 14, the rear wall sealing plate 6 is arranged between the rear wall outer panel 5 and the rear wall inner panel left plate 11 in the first cavity 14, as shown in Figure 2As shown, the rear outer panel 5 and the side outer wall of the second plate part 112 are in a fixed connection state, and the first cavity 14 has a certain height in the vertical direction. In order to further improve the torsional stiffness of the first connecting shell part 1, a rear wall 6 is arranged between the rear outer panel 5 and the left plate part 11 of the rear inner panel, and the rear wall 6 is arranged horizontally. The rear outer panel 5 and the left plate part 11 of the rear inner panel are connected as a whole in the horizontal direction, the stability of the shape of the first cavity 14 is ensured, and the torsional stiffness of the rear part of the vehicle body and the back door mode of the entire D-column lower joint structure 100 are also obviously improved.

[0049] As Figures 1 to 4 The application also provides an automobile 200, which comprises the D-column lower joint structure 100, and the specific structure of the D-column lower joint structure 100 is as described above. Since the automobile 200 adopts all the technical solutions of the above-mentioned embodiments, at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments are achieved, and the beneficial effects will not be described here.

[0050] The above-mentioned is only an exemplary embodiment of the application, and does not limit the patent scope of the application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like within the technical concept of the application and the content of the specification and drawings are included in the patent protection scope of the application.

Claims

1. A D-pillar under-joint structure, applied to automobiles with top and bottom doors, characterized in that, The D-pillar lower joint structure comprises: a first connecting shell portion, an inner side of which is formed with a first cavity, and the first connecting shell portion is formed with a first mounting surface corresponding to an inner side of a tailgate opening of the sunroof vehicle; and a second connecting shell portion, which is arranged in a concave shape, and an opening of a concave end of the second connecting shell portion is connected with the first mounting surface, so that a second cavity is formed between the second connecting shell portion and the first mounting surface; the first connecting shell portion comprises a rear wall inner panel left side plate, a tail lamp seat plate and a side wall outer panel, which are sequentially connected to enclose the first cavity the D-pillar lower joint structure further comprises a rear wall inner panel and a rear wall outer panel; the rear wall inner panel left side plate is in an L-shaped structure, which comprises a first plate portion and a second plate portion connected with each other, the first plate portion is arranged opposite to the rear wall sealing plate, the second plate portion is arranged corresponding to the side wall outer panel, and a side of the second plate portion away from the first cavity forms the first mounting surface; the second plate portion, the side wall outer panel and the tail lamp seat plate are connected with the rear wall outer panel, and the rear wall inner panel is connected with the second plate portion and the rear wall outer panel; a rear wall sealing plate is arranged between the rear wall outer panel and the rear wall inner panel left side plate in the first cavity.

2. The D-pillar lower joint structure of claim 1, wherein the second plate portion is arranged in an arc shape, and the concave end opening of the second connecting shell portion is welded with the arc-shaped first mounting surface.

3. The D-pillar lower joint structure of claim 1, wherein the second connecting shell portion is arranged corresponding to an end portion of a lower back door of the sunroof vehicle; a groove bottom of a concave groove of the second connecting shell portion is provided with a plurality of mounting holes, the plurality of mounting holes are communicated between inner and outer sides of the second cavity, and the lower back door fixing structure is arranged at the plurality of mounting holes.

4. The D-pillar lower joint structure of claim 3, wherein the lower back door fixing structure comprises a door lock structure fixing portion and a retractor fixing portion, and the door lock structure fixing portion and the retractor fixing portion are respectively fixedly installed at the plurality of mounting holes.

5. The D-pillar lower joint structure of claim 4, wherein the second cavity is provided with a door lock fixing reinforcement plate and a retractor fixing portion fixing reinforcement plate fixedly connected with the second connecting shell portion corresponding to positions of the plurality of mounting holes, and the door lock structure fixing portion and the retractor fixing portion are respectively installed on the door lock fixing reinforcement plate and the retractor fixing portion fixing reinforcement plate.

6. An automobile characterized by comprising: The D-pillar lower joint structure comprises: a first connecting shell portion, an inner side of which is formed with a first cavity, and the first connecting shell portion is formed with a first mounting surface corresponding to an inner side of a tailgate opening of the sunroof vehicle; and a second connecting shell portion, which is arranged in a concave shape, and an opening of a concave end of the second connecting shell portion is connected with the first mounting surface, so that a second cavity is formed between the second connecting shell portion and the first mounting surface; the first connecting shell portion comprises a rear wall inner panel left side plate, a tail lamp seat plate and a side wall outer panel, which are sequentially connected to enclose the first cavity the D-pillar lower joint structure further comprises a rear wall inner panel and a rear wall outer panel; the rear wall inner panel left side plate is in an L-shaped structure, which comprises a first plate portion and a second plate portion connected with each other, the first plate portion is arranged opposite to the rear wall sealing plate, the second plate portion is arranged corresponding to the side wall outer panel, and a side of the second plate portion away from the first cavity forms the first mounting surface; the second plate portion, the side wall outer panel and the tail lamp seat plate are connected with the rear wall outer panel, and the rear wall inner panel is connected with the second plate portion and the rear wall outer panel; a rear wall sealing plate is arranged between the rear wall outer panel and the rear wall inner panel left side plate in the first cavity. the second plate portion is arranged in an arc shape, and the concave end opening of the second connecting shell portion is welded with the arc-shaped first mounting surface. the second connecting shell portion is arranged corresponding to an end portion of a lower back door of the sunroof vehicle; a groove bottom of a concave groove of the second connecting shell portion is provided with a plurality of mounting holes, the plurality of mounting holes are communicated between inner and outer sides of the second cavity, and the lower back door fixing structure is arranged at the plurality of mounting holes. the lower back door fixing structure comprises a door lock structure fixing portion and a retractor fixing portion, and the door lock structure fixing portion and the retractor fixing portion are respectively fixedly installed at the plurality of mounting holes. the second cavity is provided with a door lock fixing reinforcement plate and a retractor fixing portion fixing reinforcement plate fixedly connected with the second connecting shell portion corresponding to positions of the plurality of mounting holes, and the door lock structure fixing portion and the retractor fixing portion are respectively installed on the door lock fixing reinforcement plate and the retractor fixing portion fixing reinforcement plate. The D-pillar lower joint structure comprises:

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