Vehicle frame structure

Abstract

The invention provides a vehicle frame structure. The vehicle frame structure includes: a pair of rear side members (34) extending in a vehicle front-rear direction at a lower portion of a vehicle (10); and a first cross member (44b) connecting the pair of rear side members (34), the first cross member (44b) including: an intermediate member (56) extending in a vehicle width direction at a position lower than the rear side members (34) and located at a lower side of the motor unit (50); and a pair of connecting members (58) extending obliquely downward from the rear side member (34) toward the end of the intermediate member (56) in the vehicle width direction.

Description

[0001] This application is a divisional application of the invention patent application with Chinese national application number 2020105886071, application date June 24, 2020, and invention name “Vehicle Frame Structure”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of Japanese Patent Application No. 2019-121188 filed on June 28, 2019, the entire contents of which including specification, claims, drawings, and abstract are hereby incorporated by reference. Technical Field

[0004] In this specification, a vehicle frame structure provided at a lower portion of a vehicle is disclosed. Background Art

[0005] An electric vehicle having a motor as a power source has long been widely known. In the electric vehicle, a motor unit formed by unitizing the motor and a gear for reducing the output of the motor is housed in a power unit chamber. The power unit chamber is usually located at the front lower part or the rear lower part of the vehicle. In order to ensure a relatively wide vehicle compartment, it is required to eliminate the ineffective space of the power unit chamber as much as possible and to miniaturize the power unit chamber.

[0006] Here, there has been known a technique in which a pair of side members extending in the vehicle front-rear direction and a cross member connecting the pair of side members are provided in the power unit chamber, and the cross member is disposed below the motor unit.

[0007] For example, Patent Document 1 discloses a structure for supporting a motor unit by using two transverse members arranged in a row in the front-rear direction of a vehicle. In Patent Document 1, the left and right ends of the rear transverse member are bent upward, thereby making the middle portion of the rear transverse member in the vehicle width direction lower than the side members and the motor unit. With the above structure, it is possible to ensure a wide space above the middle portion of the rear transverse member, and thus it is possible to suppress the installation height of the motor unit arranged above the middle portion to be low.

[0008] Prior Art Literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2011-116250

[0011] However, in Patent Document 1, a portion of the lateral member that extends in the vehicle width direction at a lower position compared to the side member (hereinafter referred to as the "intermediate portion") and a portion that connects the intermediate portion to the side member (hereinafter referred to as the "connection portion") are formed of a single continuous member. In this case, a relatively large bent portion needs to be provided at the portion where the transition is made from the intermediate portion to the connection portion. Above and below this bent portion, it is difficult to arrange the members, which easily results in ineffective space. That is to say, as in Patent Document 1, when the intermediate portion and the connection portion of the lateral member are constituted by a single continuous member, the ineffective space in the power unit chamber cannot be sufficiently reduced.

[0012] Therefore, in this specification, a vehicle frame structure capable of further reducing the ineffective space in the power unit chamber is disclosed. Summary of the Invention

[0013] The vehicle frame structure disclosed in this specification is characterized in that it includes: a pair of side members that extend in the vehicle longitudinal direction at the lower part of the vehicle; a first lateral member that connects the pair of side members, and the first lateral member includes: an intermediate member that extends in the vehicle width direction at a lower position compared to the side member and is located below the motor unit; a pair of connection members that are connected to both ends of the intermediate member in the vehicle width direction and each extend downward or obliquely downward in a manner that tends from the side member toward the end of the intermediate member in the vehicle width direction.

[0014] By configuring the first lateral member to include an intermediate member and a pair of connection members connected to both ends of the intermediate member in the vehicle width direction, it is also possible not to provide a relatively large bent portion at both ends of the first lateral member in the vehicle width direction. Moreover, since there is no bent portion, the ineffective space in the power unit chamber can be reduced.

[0015] In this case, the following manner can also be adopted, that is, the connection member is detachably coupled to the end of the intermediate member in the vehicle width direction through a coupling member.

[0016] By adopting the related structure, the motor unit can be easily removed from the vehicle by approaching and operating from the lower side of the vehicle to remove the intermediate member from the connection member. Moreover, thereby the maintainability of the motor unit can be improved.

[0017] Further, the following configuration may be adopted, that is, a second lateral member is further provided, which connects the pair of side members at a position outside the first lateral member in the vehicle longitudinal direction, and the middle portion of the second lateral member in the vehicle width direction faces the motor unit in the vehicle longitudinal direction.

[0018] With the structure described above, when a vehicle collision occurs, the collision load is input to the second lateral member prior to the motor unit, so that the collision load input to the motor unit can be reduced, and the motor unit can be more reliably protected.

[0019] In this case, the following configuration may be adopted, that is, a torsion bar is provided, which extends outward in the vehicle longitudinal direction from the lower part of the motor unit and is coupled to the bottom surface of the second lateral member.

[0020] By providing the torsion bar described above, the swing of the motor unit can be reduced. In addition, by coupling the torsion bar to the bottom surface of the second lateral member, it is possible to approach and operate from the lower side of the vehicle, and the torsion bar can be easily removed from the vehicle.

[0021] In addition, the following configuration may be adopted, that is, the intermediate member is linear and extends straight in the vehicle width direction.

[0022] In this way, by simplifying the shape of the intermediate member, it is difficult to generate ineffective space, and the manufacturing cost of the intermediate member can be reduced.

[0023] According to the vehicle frame structure disclosed in this specification, the ineffective space in the power unit chamber can be further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A perspective view for observing the vehicle from the outside.

[0025] Figure 2 A perspective view inside the vehicle for observing the front of the vehicle from the center of the vehicle.

[0026] Figure 3 A perspective view inside the vehicle for observing the rear of the vehicle from the front of the vehicle.

[0027] Figure 4 A perspective view observed from the side of the main frame of the vehicle.

[0028] Figure 5 A perspective view observed from the rear of the main frame of the vehicle.

[0029] Figure 6 A schematic view for observing the power unit chamber from the side.

[0030] Figure 7 is a perspective view of the first transverse member.

[0031] Figure 8 is an exploded perspective view of the first transverse member.

[0032] Figure 9 is a front view of the periphery of the end in the vehicle width direction of the first transverse member.

[0033] Figure 10 is a front view of the periphery of the end in the vehicle width direction of the transverse member of the comparative example. Detailed Description of the Invention

[0034] Hereinafter, the structure of the vehicle 10 will be described with reference to the drawings. In addition, in each of the drawings referred to below, "Fr", "Up", and "L" respectively represent the front of the vehicle, the upper part of the vehicle, and the left side in the vehicle width direction.

[0035] First, with reference to Figures 1 to 5 , a brief description of the overall structure of the vehicle 10 will be given. Figure 1 is a perspective view of observing the vehicle 10 from the outside. In addition, Figure 2 is a perspective view inside the vehicle observing the front of the vehicle from the center of the vehicle, Figure 3 is a perspective view inside the vehicle observing the rear of the vehicle from the front part of the vehicle. Moreover, Figure 4 , Figure 5 is a perspective view of the main frame 12 of the vehicle 10.

[0036] The vehicle 10 is used as a bus that travels along a specified route in a specific area in an autonomous driving mode while transporting passengers. However, the usage mode of the vehicle 10 disclosed in this specification can be appropriately changed. For example, the vehicle 10 can also be used as a movable business space. For example, the vehicle 10 can also be used as a retail store that displays and sells various goods, or a restaurant that cooks and provides meals. In addition, as another mode, the vehicle 10 can also be used as an office for conducting office work or negotiating with customers. In addition, the vehicle 10 can also be used as a taxi, bus, or transport vehicle for transporting customers or goods. In addition, the usage scenario of the vehicle 10 is not limited to business. For example, the vehicle 10 can also be used as a personal means of transportation. In addition, the driving mode or driving speed of the vehicle 10 can also be appropriately changed.

[0037] The vehicle 10 is an electric vehicle having a driving motor as a prime mover, and a main battery (not shown) for supplying power to the driving motor is mounted under the floor of the vehicle 10. As Figure 1As shown, the vehicle 10 does not have an engine hood or a trunk, but has a substantially rectangular parallelepiped-shaped outer shape with a front end face and a rear end face standing upright in a substantially vertical manner. A pair of front wheels 18 are provided near the front end of the vehicle 10, and a pair of rear wheels 20 are provided near the rear end. On the side surface of the vehicle 10, a relatively large window 13 is provided. In addition, at the center of the left side surface of the vehicle 10, a double-opening sliding-type door 22 that opens and closes in a sliding manner in the front-rear direction of the vehicle is provided.

[0038] On the front end face of the vehicle 10, a window 13 that functions as a windshield and a lamp arrangement portion 14 disposed below the window 13 are provided. On the lamp arrangement portion 14, signal lamps 15 for making people outside the vehicle aware of the presence and operating conditions of the vehicle through light are arranged. At the lower end of the lamp arrangement portion 14, a grille 24 for guiding external air into the vehicle is provided. The rear end face of the vehicle 10 has substantially the same structure as the front end face of the vehicle, with the window 13 and the lamp arrangement portion 14 arranged vertically, and a grille 24 is arranged at the lower end of the lamp arrangement portion 14. Therefore, the vehicle 10 in this example has a substantially front-rear symmetric appearance.

[0039] As Figure 2 shown, in the front part of the passenger compartment of the vehicle 10, an operation panel 26 for receiving instructions from the operator is provided. In addition, the front end of the floor panel 76 bulges upward, thereby forming a seat 28 on which the occupant can sit facing the rear of the vehicle. Similarly, as Figure 3 shown, the rear end of the floor panel 76 bulges, thereby forming a seat 28 on which the occupant can sit facing the front of the vehicle. Around the door 22 in the passenger compartment, no large interior decoration items such as seats are fixedly provided, thereby ensuring a wide space.

[0040] The vehicle 10 in this example has a body-on-frame structure in which a box-shaped body 16 is mounted on a trapezoidal main frame 12. As Figure 4 , Figure 5 shown, the main frame 12 is roughly divided into a front portion Pf located between a pair of front wheels 18, a rear portion Pr located between a pair of rear wheels 20, and a central portion Pc located between the front portion Pf and the rear portion Pr. On the front portion Pf, a pair of front side members 30 extending in the front-rear direction of the vehicle and three front transverse members 42a, 42b, 42c connecting the pair of front side members 30 are provided. The front transverse member 42c connects the rear ends of the two front side members 30 to each other. From the upper surface of the front side member 30, a suspension tower 36 for mounting an air suspension (not shown) is erected.

[0041] The rear portion Pr is also provided with a pair of rear side members 34 extending in the vehicle front-rear direction, and rear cross members 44a, 44b, 44c connecting the pair of rear side members 34, in the same manner as the front portion Pf. The rear cross member 44a connects the front ends of the two rear side members 34 to each other. From the upper surface of the rear side member 34, a suspension tower 36 for mounting an air suspension (not shown) is erected.

[0042] On the central portion Pc, a pair of central side members 32 extending in the vehicle front-rear direction, and a plurality of intermediate cross members 46a, 46b, 46c, 46d, 46e connecting the pair of central side members 32 are provided. The intermediate cross member 46a connects the front ends of the pair of central side members 32 to each other, and the intermediate cross member 46e connects the rear ends of the pair of central side members 32 to each other. In addition, the intermediate cross member 46b is adjacently provided behind the intermediate cross member 46a, and the intermediate cross member 46d is adjacently provided in front of the intermediate cross member 46e. In other words, at the front end and the rear end of the central portion Pc, two intermediate cross members 46 extending in the vehicle width direction are arranged in a stacked manner in the front-rear direction. Thereby, deformation of the central portion Pc is more effectively prevented.

[0043] Here, from Figure 4 , Figure 5 it can be clearly known that the central portion Pc is located lower than the front portion Pf and the rear portion Pr. Therefore, at the boundary between the central portion Pc and the front portion Pf, a recoil member 41 extending vertically to connect the front cross member 42c and the intermediate cross member 46a is provided. Similarly, at the boundary between the central portion Pc and the rear portion Pr, a recoil member 41 extending vertically to connect the intermediate cross member 46e and the rear cross member 44a is also provided.

[0044] The cross members and side members other than the intermediate cross member 46c are square tubular members with a rectangular cross section. In addition, although all side members and cross members are simply shown in Figure 4 , Figure 5 they are all formed with through holes 51 (triangular holes in the illustrated example) on their sides or upper and lower surfaces, as shown in the "Detailed Content of Part A" in Figure 4 . By forming the through holes 51 involved, the weight of the main frame 12 can be significantly reduced. In addition, by forming the through holes 51, a part of the wiring and piping can pass through the through holes 51 and penetrate into the interior of the square tubular side members or cross members.

[0045] On the main frame 12 as described above, a prime mover, a power transmission device, a brake device, a traveling device, a suspension device, a steering device, an electrical device, etc. are assembled, and a chassis is constituted. Here, as described above, the front portion (the portion corresponding to the front portion Pf) and the rear portion (the portion corresponding to the rear portion Pr) of the floor panel 76 bulge upward. Most of the above-described prime mover and various devices are arranged in the lower space of the bulging portion of the floor panel 76. In particular, in the space below the bulging portion at the rear of the floor panel 76 (the lower rear corner portion of the vehicle 10 and the portion between a pair of rear wheels 20), a motor unit 50 including a traveling motor is housed. Therefore, hereinafter, the space below the bulging portion at the rear of the floor panel 76 will be referred to as the "power unit chamber 48".

[0046] The box-shaped body 16 is assembled on the main frame 12. On the outer side surfaces of the side members 30, 32, 34, a plurality of cab support brackets 39 for loading and fixing the body 16 are protrudingly formed. As Figure 1 shown, the body 16 has, for example, columns 38 extending in the vehicle up-and-down direction, and beams 40 extending in the front-rear direction along the boundary between the side surface and the top surface of the vehicle 10.

[0047] Next, the arrangement of the motor unit 50 will be described with reference to Figure 6 FIG. Figure 6 FIG. 12 is a schematic view for observing the power unit chamber 48 from the side. The motor unit 50 is a component in which, in addition to the traveling motor, units such as a gear set for transmitting the output of the traveling motor are unitized and housed in a housing. As described above, the motor unit 50 is housed in the power unit chamber 48 under the rear floor of the vehicle 10.

[0048] In the power unit chamber 48, there are a pair of rear side members 34 extending in the vehicle front-rear direction, and three rear transverse members 44a, 44b, 44c extending in the vehicle width direction and connecting the pair of rear side members 34. Hereinafter, the middle rear transverse member 44b among the three rear transverse members 44a, 44b, 44c will be referred to as the "first transverse member 44b". In addition, the rear transverse member 44 located behind (i.e., outside in the vehicle front-rear direction) the first transverse member 44b will be referred to as the "second transverse member 44c".

[0049] As Figure 6 shown, the motor unit 50 is suspended and held above the first transverse member 44b by a motor mounting bracket 52 mounted on the rear side member 34. In addition, the shape and mounting position of the motor mounting bracket 52 can be appropriately changed.

[0050] Starting from the bottom of the motor unit 50, a torsion bar 54 extends rearwardly toward the rear of the vehicle 10. The torsion bar 54 is coupled to the bottom surface of the second transverse member 44c. Further, by fixing the torsion bar 54 to the second transverse member 44c, the swing of the motor unit 50 about the vertical axis is effectively prevented.

[0051] Here, as described above, the motor unit 50 is disposed above the first transverse member 44b. When the arrangement height of the first transverse member 44b is relatively high, correspondingly, the upper surface height of the motor unit 50 also becomes high, and thus the arrangement height of the floor panel 76 serving as the upper surface of the power unit chamber 48 also becomes high. As a result, the space inside the passenger compartment may become narrow. In the present example, in order to suppress the arrangement of the motor unit 50 to a lower level, both end portions of the first transverse member 44b extend downward from the rear side member 34, and the middle portion of the first transverse member 44b is located below the rear side member 34. In another expression method, in the present example, the first transverse member 44b on which the motor unit 50 is mounted is formed in a substantially U-shaped that opens upward when viewed from the front. By adopting the structure described above, the arrangement height of the motor unit 50 can be suppressed to a lower level, and thus a wider passenger compartment space can be ensured.

[0052] The structure of the first transverse member 44b will be described in more detail. Figure 7 FIG. is a perspective view of the first transverse member 44b, Figure 8 is an exploded perspective view of the first transverse member 44b. The first transverse member 44b is roughly divided into an intermediate member 56 and a pair of connecting members 58. The intermediate member 56 is a frame member that extends in the vehicle width direction at a position lower than the rear side member 34. As Figure 7 , Figure 8 shown, the intermediate member 56 is a square tube having a substantially rectangular cross section. Further, the intermediate member 56 has a substantially fixed upper surface height and is in a substantially linear shape that extends straight in the vehicle width direction when viewed from above. The motor unit 50 is suspended and held above the intermediate member 56 by a motor mounting bracket 52. Alternatively, the motor unit 50 may not be suspended and held, but may be loaded and fixed on the intermediate member 56. In this case, the vehicle front-rear direction dimension of the intermediate member 56 is not necessarily fixed, and the front-rear direction dimension may be locally increased only for the loading portion of the motor unit 50. Further, as another method, a plate for loading the motor unit 50 may be added near the loading portion of the motor unit 50 in the intermediate member 56.

[0053] The connecting member 58 is a member connected to both ends in the vehicle width direction of the intermediate member 56. Each connecting member 58 extends downward or obliquely downward from the rear side member 34 toward the intermediate member 56. The connecting member 58 is a member completely separate from the intermediate member 56, and the intermediate member 56 is connected to the connecting member 58 by a connection method such as bonding or welding. In this example, in order to improve the maintainability of the motor unit 50, the intermediate member 56 and the connecting member 58 are bolted together so that both the intermediate member 56 and the connecting member 58 can be separated without being damaged. In addition, the intermediate member 56 may use other coupling members instead of bolts, such as pins or screws, so as to be detachably coupled to the connecting member 58.

[0054] The connecting member 58 further includes a root portion 64, a main board 62, and a pair of connecting plates 60. The root portion 64, the main board 62, and the connecting plates 60 are joined together by welding. The main board 62 is a flat plate-shaped member arranged in a posture substantially orthogonal to the longitudinal axis direction of the intermediate member 56. A substantially rectangular cutout 62a is formed at the lower end of the main board 62. The outer shape of the cutout 62a is substantially the same as the outer shape of the intermediate member 56, and when installing, the intermediate member 56 is inserted into the cutout 62a. The root portion 64 is a member having one end welded to the main board 62 and the other end welded to the rear side member 34.

[0055] On both sides of the cutout 62a of the main board 62, a pair of connecting plates 60 that are vertically erected in the orthogonal direction with respect to the surface of the main board 62 are welded. When the intermediate member 56 is inserted into the cutout 62a, the connecting plates 60 overlap with the front wall 56f or the rear wall 56r of the intermediate member 56 in the front-rear direction. In addition, on the connecting plates 60, two plate-side holes 68 arranged in the vertical direction are formed. Similarly, member-side holes 70 are formed at positions of the front wall 56f and the rear wall 56r of the intermediate member 56 that overlap with the plate-side holes 68. And at a portion of the inner peripheral surface of the intermediate member 56 corresponding to the member-side holes 70, a nut (not shown) that is screwed with the coupling bolt 66 is arranged. Moreover, in a state where the intermediate member 56 is inserted into the cutout 62a, by passing the coupling bolt 66 through the plate-side holes 68 and the member-side holes 70 and screwing it with the nut, the intermediate member 56 is connected to the connecting member 58.

[0056] Here, as clearly described in the description so far, the intermediate member 56 is bolted to the connecting member 58 and is in a state of being detachable from the connecting member 58 fixed to the rear side member 34. By adopting the related structure, the maintainability of the motor unit 50 can be improved. That is, although it is necessary to remove the motor unit 50 from the motor mounting bracket 52 when maintaining the motor unit 50, it can also be assumed that in this case, the first lateral member 44b across the power unit chamber 48 will prevent the removal of the motor unit 50. According to this example, when the motor unit 50 is to be taken out of the vehicle, the intermediate member 56 located below the motor unit 50 is separated from the connecting member 58 (the coupling bolt 66 is removed), and the intermediate member 56 is removed from the vehicle 10. After that, the connection between the motor unit 50 and the motor mounting bracket 52 is released, and the motor unit 50 is taken out from the lower side of the vehicle. At this time, by simply removing the intermediate member 56 below the motor unit 50 in advance, it is possible to easily release the connection with the motor mounting bracket 52 and take out the motor unit 50 from the lower side. Moreover, the maintainability of the motor unit 50 is thus improved.

[0057] In addition, as clearly described in the description so far, in this example, the first lateral member 44b is composed of the intermediate member 56 extending in the vehicle width direction and the connecting member 58 which is an independent member from the intermediate member 56. By adopting the related structure, the invalid space in the power unit chamber 48 can be reduced. For this, reference is made to Figure 9 , Figure 10 for description. Figure 9 is the front view of the periphery of the vehicle width direction end of the first lateral member 44b of this example. In addition, Figure 10 is the front view of the periphery of the vehicle width direction end of the lateral member 100 of the comparative example.

[0058] As described so far, in this example, in order to suppress the installation height of the motor unit 50 to be relatively low, the first lateral member 44b on which the motor unit 50 is mounted is set to a substantially U-shaped such that the middle part is lower than the two end parts. As Figure 10 shown, in order to obtain the same shape, it is also considered to make the two ends of the lateral member 100 in the vehicle width direction bend upward as they tend to the outside. In this case, the middle part 100a of the lateral member 100 and the connecting part 100b connecting the middle part 100a to the rear side member 34 are formed by a continuous single member. In the related structure, it is also possible to make the middle part 100a located lower than the rear side member 34, and further suppress the installation height of the motor unit 50 to be relatively low.

[0059] However, in Figure 10In the structure shown, a relatively large bending portion 100c needs to be provided at the portion where the transition is made from the middle portion 100a to the connecting portion 100b. Above and below this bending portion 100c, it is difficult to arrange components, which is likely to result in ineffective space. That is, even if one wants to load components above the bending portion 100c, it will not be possible to stably load the components because the loading surface is curved. In addition, although it is also considered to suspend and hold components below the bending portion 100c, since the lower space 102 of the bending portion 100c becomes a substantially triangular space as Figure 10 shown, the shape of the components that can be arranged without waste is restricted. That is, as Figure 10 shown, when the middle portion 100a and the connecting portion 100b are formed by a continuous single component, the transition region D from the rear side member 34 to the middle portion 100a is often large, which is likely to generate ineffective space.

[0060] On the other hand, in this example, as repeatedly described, the middle component 56 extending in the vehicle width direction and the connecting component 58 connecting the middle component 56 to the rear side member 34 are constituted by separate components. As a result, there is no need to provide a relatively large bending portion on the first transverse member 44b, and thus the connecting component 58 and the middle component 56 can be connected at a relatively steep angle (for example, approximately 90 degrees). Moreover, by adopting the structure involved, the transition region D from the rear side member 34 to the middle component 56 can be significantly reduced compared with Figure 10 the comparative example. Thus, the ineffective space in the power unit chamber 48 can be reduced, and the space efficiency of the power unit chamber 48 can be improved. If another expression method is adopted, even if the size of the supported motor unit 50 is the same, according to the technology of this example, compared with Figure 10 the technology of the comparative example, the size of the transverse member can also be reduced. As a result, according to the technology of this example, the power unit chamber 48 can be miniaturized, and further the vehicle 10 can be miniaturized.

[0061] In addition, a second transverse member 44c is arranged behind the first transverse member 44b (outside in the vehicle front-rear direction). The two end portions of the second transverse member 44c are bent such that its middle portion is lower than the two end portions (refer to Figure 5 ). However, although the arrangement height of the middle portion of the second transverse member 44c is lower than that of the rear side member 34, it is higher than that of the middle component 56 of the first transverse member 44b. As a result, as Figure 6 shown, the middle portion of the second transverse member 44c is opposed to the motor unit 50 in the front-rear direction. By adopting the arrangement involved, the motor unit 50 can be more reliably protected during a rear collision.

[0062] That is, in the case where an obstacle (e.g., another vehicle traveling behind) collides with the rear of the vehicle, the collision load is input to the second lateral member 44c prior to the motor unit 50. Moreover, part or all of the collision load is dispersed and transmitted to the second lateral member 44c or the rear side member 34 connected to the second lateral member 44c, and is absorbed by the deformation and flexure of these components. As a result, the collision load input to the motor unit 50 can be significantly reduced, thereby effectively preventing damage to the motor unit 50.

[0063] In addition, in this example, the bottom surface of the second lateral member 44c is made to be approximately the same height as the torsion bar 54, and the torsion bar 54 is coupled to the bottom surface of the second lateral member 44c. By coupling the torsion bar 54 to the second lateral member 44c, as described above, the swing of the motor unit 50 about the vertical axis can be reduced. In addition, when the motor unit 50 is normally removed from the vehicle 10, access and operation are performed from the lower side of the vehicle 10. By coupling the torsion bar 54 extending from the motor unit 50 to the bottom surface of the second lateral member 44c, the torsion bar 54 and the motor unit 50 can be easily removed from the lower side of the vehicle 10. As a result, the maintainability of the motor unit 50 can be improved.

[0064] In addition, the structure described so far is an example, and as long as the first lateral member includes an intermediate member 56 that extends in the vehicle width direction at a position lower than the side member, and a pair of connecting members 58 that extend downward or obliquely downward in a manner that converges from the side member toward the vehicle width direction end of the intermediate member 56, other structures can also be changed. For example, in this example, the connecting member 58 is composed of a plurality of components (main board 62, connecting board 60, and root 64) that are welded to each other, but the connecting member 58 can be a single component or can be composed of a combination of more components. In addition, as long as the intermediate member 56 is located below the motor unit 50, other structures can also be appropriately changed. For example, the intermediate member 56 can also be composed of a combination of a plurality of components that are divided vertically, horizontally, or longitudinally. In addition, the intermediate member 56 and the connecting member 58 only need to be independent components, and do not necessarily have to be a detachable structure. That is, the intermediate member 56 and the connecting member 58 can also be connected in a non-separable manner, for example, by being joined together by welding.

[0065] In addition, although the power unit chamber 48 has been provided at the lower rear portion of the vehicle 10 in the description so far, the power unit chamber 48 may be provided at other locations, such as the lower front portion of the vehicle 10, as long as it is located at the lower portion of the vehicle 10. When the power unit chamber 48 is provided at the lower front portion of the vehicle 10, the second lateral member opposed to the motor unit 50 in the vehicle front-rear direction may be provided in front of the first lateral member located below the motor unit 50. Also, although in this example, a substantially box-shaped vehicle that implements low-speed autonomous driving has been described as an example, the vehicle frame structure disclosed in this example may also be mounted on other types of vehicles.

[0066] Reference Signs

[0067] 10…Vehicle; 12…Main frame; 13…Window; 14…Lamp arrangement section; 15…Signal lamp; 16…Body; 18…Front wheel; 20…Rear wheel; 22…Door; 24…Grille; 26…Operation panel; 28…Seat; 30…Front side member; 32…Central side member; 34…Rear side member; 36…Suspension tower; 38…Column; 40…Beam; 41…Recoil member; 42a, 42b, 42c…Front lateral member; 44a…Rear lateral member; 44b…First lateral member; 44c…Second lateral member; 46a, 46b, 46c, 46d, 46e…Intermediate lateral member; 48…Power unit chamber; 50…Motor unit; 51…Through hole; 52…Motor mount; 54…Torsion bar; 56…Intermediate member; 58…Linking member; 60…Linking plate; 62…Main board; 62a…Cutout; 64…Root; 66…Binding bolt; 68…Hole on the plate side; 70…Hole on the member side; 76…Floor panel; 100…Lateral member; 100a…Intermediate portion; 100b…Linking portion; 100c…Bending portion; D…Transition region; Pc…Central portion; Pf…Front portion; Pr…Rear portion.

Claims

1. A vehicle frame structure, characterized in that, Comprising: A pair of side members extending along the longitudinal direction of the vehicle at the lower part of the vehicle; A first transverse member connecting the pair of side members, The first transverse member comprising: An intermediate member extending along the vehicle width direction at a position lower than the side member, located below the motor unit, and having a fixed upper surface height; A pair of connecting members bolted to both ends of the intermediate member in the vehicle width direction, and each extending downward or obliquely downward in a manner tending from the side member toward the vehicle width direction end of the intermediate member.

2. The vehicle frame structure according to claim 1, characterized in that The connecting member is welded to the side member.

3. The vehicle frame structure according to claim 1, characterized in that The bolt connection is implemented by inserting a bolt along the longitudinal direction of the vehicle.

4. The vehicle frame structure according to claim 1, characterized in that The main frame of the vehicle is trapezoidal in shape, The main frame includes the pair of side members and the first transverse member.

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