FRONT STRUCTURE FOR ELECTRIC VEHICLES

Abstract

[Problem to be solved] To enable the deformation of a front structure in an intended deformation mode to effectively absorb impact energy when a shock load is applied to the front structure of an electric vehicle. [Solution] In the front structure for the electric vehicle, an inner part 21 with varying stiffness is provided on a front part in an inner part of a front longitudinal member 10; in the inner part with varying stiffness 21, several sections with low stiffness 21a and several sections with high stiffness 21b are arranged alternately in a front-rear direction of the vehicle; and on the front longitudinal member 10 behind the inner part with varying stiffness 21, a weak part 25 is provided which has a lower stiffness than the sections with high stiffness 21b.

Description

[Technical field]

[0001] The present invention relates to front structures for electric vehicles. [State of the art]

[0002] A vehicle front section has a mechanism for absorbing impact energy caused by a shock load when subjected to an impact load, such as that caused by a frontal collision or the like. For example, as disclosed in patent literature 1, a structure is known that is provided with a weak part on an element constituting the front section of a vehicle body.

[0003] The structure disclosed in patent literature 1 comprises front longitudinal members arranged on opposite sides in the front section of the vehicle in the direction of the vehicle's width, and a subframe arranged beneath the front longitudinal members, each front longitudinal member having a portion with varying stiffness and the subframe having a weaker portion. When an impact load is applied to the front of the vehicle body from the front, elements such as a bumper support and a bumper support extension in this structure are compressed immediately after the impact to absorb some of the impact energy caused by the shock load. The shock load is then transferred to the front longitudinal member and the subframe.

[0004] The variable-stiffness section provided in the front longitudinal member has a recessed section located on a central portion of the front longitudinal member in the front-to-rear direction of the vehicle. This recessed section deforms to bend inwards towards the width of the vehicle when subjected to an impact load. Additionally, the weaker portion of the subframe deforms to bend downwards when subjected to an impact load.

[0005] In this way, in the structure of the above example, the part with different stiffness and the weak part are deformed in order to stably absorb the impact energy caused by a shock load, for example, when a shock load acts on the bumper support and the like of the front of the vehicle. [List of reference literature][Patent literature]

[0006] [Patent Literature 1] JP 2016-150685 A [Summary of the invention][Problems to be solved by the invention]

[0007] Additionally, in a structure where a weak point is present on each of several elements comprising the front of a vehicle body, such as the structure in the example above, not every weak point can deform in an intended mode when subjected to an impact load. For example, immediately after an impact load acts on the front of the vehicle body, a bumper support and the like are compressed, and depending on the magnitude and direction of deformation of these elements, an unintended load transfer occurs to a front longitudinal member and a subframe, such that only one of a part with differing stiffness and the weak point can deform. In such a case, it can be difficult to absorb the impact as intended.

[0008] For example, if the weaker part of the subframe is designed to be stiffer than the part with the different stiffness, and if an impact load is applied due to a frontal collision, only the part with the different stiffness can deform. In such a case, the front longitudinal member can be excessively compressed, and therefore the deflection of an instrument panel subjected to the impact load can be greater than expected.

[0009] In the structure of the above example, there is therefore room to improve the deformation of the element that makes up the front of the vehicle in an intended deformation mode in order to absorb the impact energy caused by the shock load when a shock load acts on the front structure of the vehicle due to a frontal impact or the like.

[0010] The present invention was devised to solve the above problem, and one of its objectives is to provide a front structure for an electric vehicle that is capable of deforming the front structure in an intended deformation mode and effectively absorbing impact energy when a shock load is applied to the front structure of the electric vehicle. [Means of solving the problems]

[0011] To achieve the above objective, a front structure of an electric vehicle according to the present invention comprises longitudinal members (lateral elements) arranged in a front part of the vehicle on opposite sides in the direction of the vehicle width and extending in a front-rear direction of the vehicle, and a motor frame arranged under the longitudinal members in the vehicle and supporting an electric motor.In the front structure of the electric vehicle, a section with varying stiffness is provided on a front part in an inner part of the longitudinal member in the direction of the vehicle width, in which several sections with low stiffness and several sections with high stiffness, which have a higher stiffness than the sections with low stiffness, are arranged alternately in the front-rear direction of the vehicle, and behind the section with varying stiffness on the longitudinal member of the vehicle, a weak section is provided which has a lower stiffness than the sections with high stiffness. [Advantageous effect of the invention]

[0012] When an impact load acts on the front structure of an electric vehicle, it is possible according to the present invention to deform the front structure in an intended deformation mode and to effectively absorb impact energy. [Brief description of the drawings] [ Fig. 1] Fig. Figure 1 is a schematic perspective view showing an embodiment of a front structure of an electric vehicle according to the present invention. [ Fig. 2] Fig. Figure 2 is a schematic side view of a front longitudinal member on the left side of Fig. 1. Viewed from the inside in the direction of the vehicle width. [ Fig. 3] Fig. Figure 3 is a top view of the front longitudinal member of Fig. 2. [ Fig. 4] Fig. Figure 4 is a schematic perspective view showing a state in which an inner element of the front longitudinal member of Fig. 2 has been taken. [ Fig. 5] Fig. Figure 5 is a schematic side view of the front longitudinal member and the like. Fig. 2. Viewed from the outside in the direction of the vehicle width. [ Fig. 6] Fig. Figure 6 is a schematic perspective view of the front longitudinal beam and the like. Fig. 2nd view from below. [ Fig. 7] Fig. Figure 7 is a bottom view of the front longitudinal member on the left side of Fig. 1 and its surroundings as seen from below inside the vehicle. [ Fig. 8] Fig. 8 is a top view of Fig. 1 with an engine frame (not shown) from Fig. 1, which represents a state in which a reinforcing plate on the right side is not shown. [Emphasis of the invention]

[0013] In the following, an embodiment of a front structure of an electric vehicle according to the present invention is described with reference to the drawings ( Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. 8) described. In the drawings, arrow Fr indicates the front in a front-to-rear direction of the vehicle. In the description of the embodiment, “a front part (front end) and a rear part (rear end)” correspond to the front part and the rear part in a front-to-rear direction of the vehicle. Arrows R and L indicate the right and left sides when an occupant in the vehicle is facing forward. Furthermore, arrow U points upward in the vertical direction of the vehicle.

[0014] The front structure for the electric vehicle of the present embodiment comprises front longitudinal members 10 (lateral elements) which are arranged in a width direction of the vehicle on opposite sides in a front part of the vehicle and extend in a front-rear direction of the vehicle, and a motor frame 45 which is arranged under each front longitudinal member 10 in the vehicle and carries an electric motor 1.Furthermore, in the front structure, on a front part in an inner part of the front longitudinal member 10 in the direction of the vehicle width, an inner part with varying stiffness 21 (part with varying stiffness) is provided, in which several sections with low stiffness 21a and several sections with high stiffness 21b, which have a higher stiffness than the sections with low stiffness 21a, are arranged alternately in the front-rear direction of the vehicle, and on the inner part of the front longitudinal member 10 in the direction of the vehicle width, which is located in the vehicle behind the inner part with varying stiffness 21, a weak part 25 is provided, which has a lower stiffness than the sections with high stiffness 21b.

[0015] As in Fig. As shown in Figure 1, the front structure of the electric vehicle of the present embodiment is arranged forward within the vehicle from a dashboard 51. The dashboard 51 is a metal sheet that separates a vehicle compartment (passenger compartment) from an engine compartment, extends in the direction of the vehicle width to connect opposite sides of a vehicle body in the direction of the vehicle width, and extends upwards from a front part of a floor panel 53, which forms a floor part of the vehicle compartment. That is to say, the front structure of the present embodiment is arranged in the engine compartment and comprises the front longitudinal member 10, the engine frame 45, a strut 19, a subframe 35, and a strut tower 31. Each element is described below.

[0016] The front longitudinal members 10 are arranged on opposite sides of the front of the vehicle in the width direction and on the inside of the front wheels (not shown) in the direction of the vehicle width. Each front longitudinal member 10 is a high-rigidity element made of a metal material and is part of a vehicle frame.

[0017] The front longitudinal member 10, located at the front of the vehicle starting from the dashboard 51, extends in the front-to-rear direction of the vehicle. The front longitudinal member 10 located beneath the dashboard 51 extends outwards in the direction of the vehicle's width as it extends rearwards and is connected to a side sill 55. Like the front longitudinal member 10, the side sill 55 is a high-rigidity element made of a metal material and is part of the vehicle frame. The side sill 55 in this example extends in the front-to-rear direction of the vehicle and is connected to an outer part of the floor panel 53 in the vehicle's width direction.

[0018] The front longitudinal member 10 of the present embodiment comprises a front inner element 11 (inner wall section, front element), a rear inner element 12 (rear element), an outer element 13 (outer wall section), an inner curved element 14, and an outer curved element 15. The inner section with differential stiffness 21 and the weak section 25 are provided in the front inner element 11. Additionally, an outer section with differential stiffness 22, which is described below, is provided in the outer element 13. The inner section with differential stiffness 21, the outer section with differential stiffness 22, and the weak section 25 are described in detail below.

[0019] First, the front inner element 11 is described. As in Fig. 2 and Fig. As shown in Figure 6, the front inner element 11 comprises an inner wall part 11a, a top part 11c, a bottom part 11d, an upper flange part 11e, and a lower flange part 11f. The front inner element 11 has a hat-shaped cross-section that opens outwards in the direction of the vehicle width. The inner wall part 11a has a wall surface that faces inwards in the direction of the vehicle width, has a predetermined length in the vertical direction of the vehicle, and extends in the front-to-rear direction of the vehicle. Furthermore, as shown in Figure 6, the inner wall part 11 is 11a. Fig. Figure 2 shows that an inner recess 11b is provided in a central part of the inner wall section 11a in the vertical direction of the vehicle. This recess extends outwards in the width direction of the vehicle and in the front-to-rear direction. The inner recess 11b has rib lines at its upper and lower ends and ensures a predetermined stiffness against a load acting in the front-to-rear direction. In other words, the inner recess 11b acts as a bulge that increases the stiffness of the inner wall section 11a.

[0020] As in Fig. 1 and Fig. As shown in Figure 3, the upper part 11c is a part that extends outwards from an upper end of the inner wall part 11a in the direction of the vehicle width and extends essentially horizontally in the front-to-rear direction of the vehicle. As shown in Fig. 6 and Fig. As shown in Figure 7, the underside part 11d is a portion that extends outwards from a lower end of the inner wall part 11a in the direction of the vehicle width, and a rear section of the underside part 11d is slightly inclined downwards as it runs backwards in the vehicle. As shown in Fig. As shown in Figure 2, the upper flange part 11e projects upwards from an outer end of the upper part 11c in the direction of the vehicle width and extends along the outer end of the upper part 11c in the front-to-rear direction of the vehicle. The lower flange part 11f projects downwards from an outer end of the lower part 11d in the direction of the vehicle width and extends along the outer end of the lower part 11d in the front-to-rear direction of the vehicle.

[0021] As in Fig. 2 and Fig. As shown in Figure 6, the rear inner element 12 is a high-stiffness element, for example made of high-tensile steel, and is connected to a rear portion of the front inner element 11. Like the front inner element 11, the rear inner element 12 comprises an inner wall section 12a, a top section 12c, a bottom section 12d, an upper flange section 12e, and a lower flange section 12f, and has a hat-shaped cross-section that opens outwards in the direction of the vehicle width. The inner wall section 12a of the rear inner element 12 has a wall surface that faces inwards in the direction of the vehicle width, has a predetermined length in the vertical direction of the vehicle, and extends in the front-to-rear direction of the vehicle.Furthermore, an inner recess 12b is provided in a central section of the inner wall part 12a in the vertical direction of the vehicle, projecting outwards in the width direction of the vehicle. The inner recess 12b extends in the front-to-rear direction of the vehicle. The inner recess 12b has rib lines at its upper and lower ends and ensures a predetermined stiffness against a load acting in the front-to-rear direction. That is, the inner recess 12b acts as a bulge that increases the stiffness of the inner wall part 12a. A front section of the inner wall part 12a of the rear inner element 12 is connected to a rear section of the inner wall part 11a of the front inner element 11.

[0022] As in Fig. 1 and Fig. As shown in Figure 4, the upper part 12c of the rear inner element 12 is a portion that extends outwards from an upper end of the inner wall part 12a in the direction of the vehicle width. Furthermore, the upper part 12c is curved downwards as it runs rearward within the vehicle. The lower part 12d of the rear inner element 12 is a portion that extends outwards from a lower end of the inner wall part 12a in the direction of the vehicle width and is curved downwards as it runs rearward within the vehicle.

[0023] As in Fig. As shown in Figure 2, the upper flange part 12e projects upwards from an outer end of the upper part 12c in the direction of the vehicle width and extends along the outer end of the upper part 12c in the front-to-rear direction of the vehicle. The lower flange part 12f projects downwards from the outer end of the lower part 11d in the direction of the vehicle width and extends along the outer end of the lower part 11d in the front-to-rear direction of the vehicle. The upper part 12c, the lower part 12d, the upper flange part 12e, and the lower flange part 12f of the rear inner element 12 are each connected to the upper part 11c, the lower part 11d, the upper flange part 11e, and the lower flange part 11f of the front inner element 11.

[0024] As in Fig. 4 and Fig. As shown in Figure 5, the outer element 13 is an element that is connected to an outer part of the front inner element 11 in the direction of the vehicle width and to an outer part of the rear inner element 12 in the direction of the vehicle width, has a predetermined length in the vertical direction of the vehicle, and extends in the front-to-rear direction of the vehicle. An upper part of the outer element 13 is connected by spot welding to the upper flange part 11e of the front inner element 11 and the upper flange part 12e of the rear inner element 12, and a lower part of the outer element 13 is connected by spot welding to the lower flange part 11f of the front inner element 11 and the lower flange part 12f of the rear inner element 12.

[0025] Furthermore, as in Fig. Figure 2 shows an outer recess 13b, which extends inwards in the width direction of the vehicle, on a central portion of the outer element 13 in the vertical direction of the vehicle, corresponding to the front inner element 11 and the inner wall portion 12a of the rear inner element 12. The outer recess 13b extends in the front-to-rear direction of the vehicle in the same way as the inner recess 11b. The outer recess 13b has rib lines at its upper and lower ends and ensures a predetermined stiffness against a load acting in the front-to-rear direction. That is, the outer recess 13b acts as a bulge that increases the stiffness of the outer element 13.The front longitudinal beam 10 has a closed cross-sectional structure with an essentially rectangular shape formed by the inner element and the outer element 13, and ensures a predetermined stiffness.

[0026] As in Fig. 6 and Fig. As shown in Figure 7, the inner curved element 14 is connected to a rear portion of the rear inner element 12. The inner curved element 14 comprises an inner wall portion 14a, a bottom portion 14d, an outer flange portion 14g, and an inner flange portion 14h. The inner wall portion 14a of the inner curved element 14 has a wall surface that faces inwards in the direction of the vehicle width and is curved outwards towards the rear of the vehicle in the direction of the vehicle width. A front portion of the inner curved element 14 is connected to the inner wall portion 12a of the rear inner element 12. The inner wall portion 14a is designed to gradually shorten towards the rear of the vehicle in the vertical direction of the vehicle. Furthermore, an outer portion of a lower cross member 40, which is described below, is spot-welded to the inner wall portion 14a in the direction of the vehicle width.The underside part 14d of the inner curved element 14 is a part that extends outwards from a lower end of the inner wall part 14a in the direction of the vehicle width, is curved outwards towards the rear of the vehicle in the direction of the vehicle width, and is also curved downwards within the vehicle. An outer part in the direction of the vehicle width in a rear section of the underside part 14d is connected to the side sill 55.

[0027] The outer flange part 14g projects upwards from an outer end of the underside part 14d and is curved along the outer end of the underside part 14d in the direction of the vehicle width. The inner flange part 14h projects inwards from an upper end of the inner wall part 14a in the direction of the vehicle width and is curved along the upper end of the inner wall part 14a. A central portion of the lower cross member 40 is connected to the inner flange part 14h in the width direction of the vehicle.

[0028] The outer curved element 15 is connected to a rear portion of the outer element 13, has a predetermined length in the vertical direction of the vehicle, and is curved outwards towards the rear of the vehicle in the direction of the vehicle's width. A lower portion of the outer curved element 15 is spot-welded to the outer flange portion 14g of the inner curved element 14. Additionally, a rear portion of the outer curved element 15 can be connected to the side sill 55.

[0029] As in Fig. 1 and Fig. As shown in Figure 5, the motor frame 45 is a frame for supporting the electric motor 1 for propulsion and is a high-rigidity element made of a metal material. The motor frame 45 comprises a frame body section 45a, which extends in the direction of the vehicle width, and side frame sections 45b, which extend forward in the vehicle from opposite sides of the frame body section 45a in the direction of the vehicle width. Each side frame section 45b is located below the front longitudinal member 10. A front section of the side frame section 45b is connected to the front part of the front longitudinal member 10 via the strut 19. Furthermore, a body coupling section 45c is provided on a central section of the side frame section 45b in the front-rear direction of the vehicle.The body coupling part 45c extends upwards in the vehicle from an upper part of the side frame part 45b, and an upper section of the body coupling part 45c is coupled to a lower part of the front longitudinal member 10 via a mounting bracket 48, which is described below.

[0030] As in Fig. As shown in Figure 1, the strut 19 is a metal part that extends in the vertical direction of the vehicle and is, like the front longitudinal member 10 and similar parts, part of the vehicle frame. The strut 19 has a front part 19a and an inner part 19b. An upper section of the front part 19a is connected to a front end of the front longitudinal member 10, and a lower section of the front part 19a is connected to the side frame part 45b of the engine frame 45. In addition, an outer flange part 13f is provided at a front end of the outer element 13, projecting outwards in the direction of the vehicle width, and the front part 19a of the strut 19 is connected to the outer flange part 13f.

[0031] Here, the parts with different stiffnesses 21 and 22 are described. As in Fig. 1 and Fig. As shown in Figure 2, the parts with different stiffnesses 21 and 22 are provided on a front part of the front longitudinal member 10 and are designed to be weaker than a rear part of the front longitudinal member 10. The parts with different stiffnesses 21 and 22 have the inner part with different stiffness 21 and the outer part with different stiffness 22.

[0032] The inner part with varying stiffness 21 is provided on a front section of the inner wall part of the front longitudinal member 10 in the direction of the vehicle width. In this example, as in Fig. 1 and Fig. As shown in Figure 2, the inner part with varying stiffness 21 is provided on a front part of the front longitudinal member 10 in the inner wall section 11a of the front inner element 11. Furthermore, the inner part with varying stiffness 21 is configured by an alternating arrangement of several sections with low stiffness 21a and several sections with high stiffness 21b in the front-rear direction of the vehicle.

[0033] In this example, each section with low stiffness 21a in the inner part with varying stiffness 21 is a recess groove that extends outwards in the direction of the vehicle width and in the vertical direction of the vehicle. As in Fig. As shown in Figure 2, two low-stiffness sections 21a are provided on the inner wall section 11a, located above the inner recess section 11b and spaced apart from each other in a front-to-rear direction. Furthermore, two low-stiffness sections 21a are provided on the inner wall section 11a, located below the inner recess section 11b and spaced apart from each other in a front-to-rear direction. The low-stiffness section 21a above the inner recess section 11b and the low-stiffness section 21a below the inner recess section 11b are vertically oriented in the vertical direction of the vehicle. The low-stiffness sections 21a located in the front and vertically oriented are positioned at a distance further rearward in the vehicle than the front end of the inner wall section 11a of the front inner element 11.

[0034] The high-stiffness section 21b of the inner part with varying stiffness 21 is a section arranged adjacent to the low-stiffness section 21a in the front-to-rear direction of the vehicle and is provided on the inner wall part 11a in front of and behind the low-stiffness section 21a. That is to say, like the low-stiffness section 21a, the high-stiffness section 21b is also provided on each inner wall part 11a located above the inner recess part 11b and on each inner wall part 11a located below the inner recess part 11b.

[0035] At the front and rear ends of the low-stiffness section 21a, web lines are formed that run in the vertical direction of the vehicle. If, for example, an impact load acts on the front end of the front longitudinal member 10 due to a frontal collision or the like, a web line becomes the starting point of the deformation, and the variable-stiffness section 21 can be deformed and compressed in the front-to-rear direction of the vehicle.

[0036] The outer part with varying stiffness 22 is provided on a front part in the outer wall section of the front longitudinal member 10 in the direction of the vehicle width. In this example, as in Fig. 3 and Fig. As shown in Figure 4, the outer part with varying stiffness 22 is provided on a front part of the outer element 13 of the front longitudinal member 10. Like the inner part with varying stiffness 21, the outer part with varying stiffness 22 is also configured by an alternating arrangement of several sections with low stiffness 22a and several sections with high stiffness 22b in the front-rear direction of the vehicle.

[0037] Each low-stiffness section 22a of the outer part with varying stiffness 22 is a recess groove cut inwards in the direction of the vehicle width and extending in the vertical direction of the vehicle. As in Fig. 4 and Fig. As shown in Figure 5, two low-stiffness sections 22a are provided on the outer element 13, located above the outer recess part 13b, and two additional low-stiffness sections 22a are provided on the outer element 13, located below the outer recess part 13b. The low-stiffness section 22a above the outer recess part 13b and the low-stiffness section 22a below the outer recess part 13b are vertically oriented in the vertical direction of the vehicle. The vertically oriented low-stiffness sections 22a located in the front part are spaced further back in the vehicle than the front end of the inner wall part 11a of the front inner element 11.

[0038] As in Fig. As shown in Figure 4, the high-stiffness section 22b of the outer part with varying stiffness 22, like the high-stiffness section 21b of the inner part with varying stiffness 21, is a section that is arranged adjacent to the low-stiffness section 22a in the front-to-rear direction of the vehicle and is provided on the outer element 13 in front of and behind the low-stiffness section 22a. That is, like the low-stiffness sections 22a, the high-stiffness sections 22b are also provided above and below the outer recess part 13b.

[0039] As in Fig. As shown in Figure 3, the low-stiffness section 22a and the high-stiffness section 22b of the outer part with different stiffness 22 are also arranged to correspond to the low-stiffness section 21a and the high-stiffness section 21b of the inner part with different stiffness 21. For example, the low-stiffness section 22a of the outer part with different stiffness 22 is arranged outwards in the direction of the vehicle width from the low-stiffness section 21a of the inner part with different stiffness 21 and is arranged such that it is aligned with the low-stiffness section 21a in the vertical direction of the vehicle.Accordingly, the high-stiffness section 22b of the outer part with different stiffness 22 is arranged outwards in the direction of the vehicle width from the high-stiffness section 21b of the inner part with different stiffness 21 and is arranged such that it is aligned with the high-stiffness section 21b in the vertical direction of the vehicle.

[0040] Furthermore, as in Fig. Figure 5 shows that at least one section of the part with different stiffness 21 and 22 is arranged further rearward in the vehicle than the front end of the engine frame 45. In this example, the front end sections of the inner part with different stiffness 21 and the outer part with different stiffness 22 are arranged further forward in the vehicle than a front end section of the side frame part 45b of the engine frame 45.

[0041] The weak part 25 is described below. The weak part 25 is provided in the front longitudinal member 10, is located in the vehicle behind the inner part with different stiffness 21, and has a lower stiffness than the inner part with different stiffness 21. In this example, as in Fig. 2 and Fig. 3 shown, the weak part 25 is provided inside in the direction of the vehicle width in a middle part of the front longitudinal member 10 in the front-rear direction of the vehicle and is designed to be weaker than the rear part of the front longitudinal member 10.

[0042] As in Fig. As shown in Figure 2, the weak part 25 is located essentially at the rear of the central section of the inner wall part 11a of the front inner element 11 in the front-to-rear direction of the vehicle. In this example, the weak part 25 is positioned at a first distance behind the inner part with differential stiffness 21 (part with differential stiffness) and at a second distance from a rear end of the front inner element 11. The first distance in the front-to-rear direction of the vehicle is set to be longer than the second distance in the front-to-rear direction of the vehicle.

[0043] The weak part 25 of the present embodiment is a recess groove that extends outwards in the direction of the vehicle width and in the vertical direction of the vehicle, the weak part 25 extending continuously from the upper end of the inner wall part 11a of the front inner element 11 to its lower end. As shown in Fig. As shown in Figure 2, the width of the recess groove of the weak part 25, located above the inner recess part 11b, is essentially uniform from the upper end of the inner wall part 11a to the upper end of the inner recess part 11b, in the front-to-rear direction of the vehicle. The width of the weak part 25, which is provided on the inner recess part 11b, decreases downwards from the upper end of the inner recess part 11b. The width of the recess groove of the weak part 25, which lies below the inner recess part 11b, is essentially uniform from the lower end of the inner recess part 11b to the lower end of the inner wall part 11a. If an impact load acts on the front end of the front longitudinal member 10 due to a frontal collision or the like, the weak part 25 can be deformed to bend convexly outwards in the direction of the vehicle width.

[0044] Both the parts with differing stiffness 21, 22 and the weak part 25 are provided in the front longitudinal member 10, so that when an impact load acts on the front part of the front longitudinal member 10, the load can be transferred to both the parts with differing stiffness 21, 22 and the weak part 25. That is, when an impact load acts, the front longitudinal member 10 can deform in an intended deformation mode in order to effectively absorb the impact energy caused by the impact load.

[0045] When an impact load is applied to the front of the vehicle due to a frontal collision or similar event, the low-stiffness section 21a, located between two high-stiffness sections 21b of the inner part with differing stiffness 21, is deformed and compressed in the front-to-rear direction of the vehicle. Similarly, the low-stiffness section 22a, located between two high-stiffness sections 22b of the outer part with differing stiffness 22, is compressed in the front-to-rear direction of the vehicle. The multiple low-stiffness sections 21a and 22a of the parts with differing stiffness 21 and 22 are compressed successively from front to rear.

[0046] Providing the inner part 21 with a different stiffness allows the inner section of the front part of the front longitudinal member 10 to be compressed. This can trigger the front part of the front longitudinal member 10 to deform in such a way that the front longitudinal member 10 bends outwards.

[0047] For example, if an object (collecting object) of a predetermined length in the vertical direction of the vehicle collides with the front of the vehicle, an impact load is exerted on the front of the vehicle. If a lower section of the front of the vehicle is located further forward than an upper section, the colliding object will collide with a front part of the engine frame 45 before colliding with the front longitudinal member 10 and then with the front part of the front longitudinal member 10. That is, the time at which the colliding object collides with the front longitudinal member 10 is slightly later than the time at which the colliding object collides with the engine frame 45.

[0048] If an impact load acts on the front of the vehicle in a longitudinal direction of the front longitudinal member 10 (in this example, a horizontal direction perpendicular to the vehicle width), even a small difference in the time of impact causes an inclination in the direction in which the impact load acts, relative to the longitudinal direction of the front longitudinal member 10. Therefore, if a load acts in a direction that is inclined relative to the longitudinal direction (axial direction) of the front longitudinal member 10, the load can initiate bending deformation in the parts with different stiffnesses 21 and 22.

[0049] When an impact load acts on the parts with different stiffnesses 21 and 22, the parts with different stiffnesses are deformed such that the section with lower stiffness 21a of the inner part with different stiffness 21 and the section with lower stiffness 22a of the outer part with different stiffness 22 are compressed. That is, the inner part with different stiffness 21 and the outer part with different stiffness 22 are deformed to be compressed in the longitudinal (axial) direction of the front longitudinal member 10. Through deformation of the inner part with different stiffness 21 and the outer part with different stiffness 22, some of the impact energy generated by the impact load is absorbed.

[0050] Subsequently, part of the impact load is transferred to the weak part 25, which is located further back than the parts with different stiffnesses 21 and 22. This causes the weak part 25 to deform, bending convexly outwards in the direction of the vehicle's width. Therefore, the amount of deformation of the weak part 25 (the amount by which the weak part 25 deforms outwards) can be set to be greater than the amount of deformation of the parts with different stiffnesses 21 and 22 (an amount of axial compression deformation, an amount of compression deformation in the front-to-rear direction). That is, the weak part 25 can absorb more impact energy than the amount of impact energy absorbed by the parts with different stiffnesses 21 and 22.

[0051] Since the central part of the front longitudinal member 10 is deformed in the front-to-rear direction of the vehicle to bend outwards, the weak part 25 is also deformed to be pushed outwards in the direction of the vehicle's width. With such deformation, the impact energy caused by a shock load can be absorbed not only by the deformation of the parts with different stiffnesses 21 and 22 and the weak part 25, but also by the entire front longitudinal member 10.

[0052] Since the deformation amount of the weak part 25 can be set to a large extent, impact energy transmitted further rearward than the dashboard 51 can be effectively reduced. That is, according to the present embodiment, it is possible to reduce the amount by which the dashboard 51 is retracted when an impact load acts on the front of the vehicle.

[0053] As in Fig. 1, Fig. 2 to Fig. As shown in Figure 3, in the present embodiment, the parts with differing stiffness 21 and 22 are provided on an inner and an outer part of the front longitudinal member 10 in the direction of the vehicle width, as described above. The parts with differing stiffness 21 and 22 provided on the inner and outer parts are each configured by an alternating arrangement of the sections with low stiffness 21a and 22a and the sections with high stiffness 21b and 22b in the front-to-rear direction of the vehicle. In this example, in the inner part with differing stiffness 21 and in the outer part with differing stiffness 22, the sections with low stiffness 21a and 22a and the sections with high stiffness 21b and 22b are arranged to form a so-called bellows shape.

[0054] As a result, the sections with low stiffness 21a and 22a and the sections with high stiffness 21b and 22b of the parts with different stiffnesses 21 and 22 are arranged in pairs in the direction of the vehicle width, so that the front part of the front longitudinal member 10 tends to be compressed like a bellows. As a result, the front part of the front longitudinal member 10 tends to be compressed in the longitudinal direction of the front longitudinal member 10.

[0055] Furthermore, the front structure of the present embodiment, as described above, comprises the strut 19, which covers a front end portion of the front longitudinal member 10, and an inner part 19b (extension portion) is provided on an inner part of the strut 19 in the direction of the vehicle width, extending rearward into the vehicle. The extension portion 19b is connected to the outer flange portion 13f of the front longitudinal member 10.

[0056] The strut 19 exerts an impact load on the front end of the front longitudinal member 10, and the inner part with different stiffness 21 is compressed, which can provide a trigger for the front longitudinal member 10 to deform in order to bend outwards.

[0057] In the front part of the front longitudinal member 10, the outer flange part 13f is provided at the front end of the outer element 13, so that the stiffness of the outer part in the direction of the vehicle width can be set higher than the stiffness of the inner part. Part of the load acting on the front longitudinal member 10 is transferred to the rear of the vehicle via the inner part 19b of the strut 19 along the inner wall part 11a of the front inner element 11, and part of the load is transferred outwards in the direction of the vehicle width via the front part 19a or the like of the strut 19.

[0058] Even at a stage where the load is transferred from the parts of the front longitudinal member 10 with differing stiffness 21 and 22 to the rear of the vehicle, and the weak part 25 begins to deform to bend outwards, the trajectory of a colliding object remains unchanged, and the impact load is transferred to the rear of the vehicle. Therefore, while the inner part with differing stiffness 21 and the outer part with differing stiffness 22 are compressed to absorb the impact, the deformation of the weak part 25 to bend outwards is favored, and an impact-absorbing effect can be maintained.

[0059] Furthermore, in the present embodiment, as described above, the outer flange part 13f is provided on an outer section of the front longitudinal member 10 in the direction of the vehicle width, and the front section 19a of the strut 19 is connected to the outer flange part 13f. In addition, through holes 21c and 21d are formed in the inner section 21 of the front longitudinal member 10, which has different stiffnesses. In this example, as in Fig. As shown in Figure 2, long through holes 21c extending in the vertical direction of the vehicle are formed in the low-stiffness sections 21a below the low-stiffness sections 21a, which are arranged on the front side of the inner part with different stiffness 21, and in the inner recess part 11b, which lies between the upper low-stiffness section 21a and the lower low-stiffness section 21a, a round through hole 21d is also formed on the front side.

[0060] By providing these through holes 21c and 21d, the stiffness of the parts with different stiffnesses 21 and 22 in the inner part of the front longitudinal member 10 is set lower than in the outer part. That is, the stiffness of the inner part with different stiffness 21 is lower than the stiffness of the outer part with different stiffness 22.

[0061] In the configuration of the present embodiment described above, the weak part 25 is deformed upon impact, bending convexly outwards in the direction of the vehicle width. Here, the outer flange part 13f and the front part 19a of the strut 19 are connected in front of the outer part with differential stiffness 22, and the long through holes 21c and the round through hole 21d are provided in the inner part with differential stiffness 21 to reduce the stiffness, so that the sections with low stiffness 21a located on the front of the inner part with differential stiffness 21 are deformed and compressed first when the impact load acts on the front side element 10. Subsequently, the inner part with differential stiffness 21 and the outer part with differential stiffness 22 are deformed in a bellows shape.

[0062] In this way, by initiating compression deformation from the inner part with differing stiffness 21, an impact load, which is transferred from the parts with differing stiffness 21 and 22 to the weaker part 25, is transferred in a direction that is slightly inclined outwards in the direction of the vehicle width, while extending rearwards in the vehicle. That is, the inner part with differing stiffness 21 is compressed first, and a load transfer path is created from the inner section in the front part of the front longitudinal member 10 to the outer section in the rear part. Fig. For example, in step 3 a transmission path is formed in the direction of arrow X. This allows the weak part 25 to be deformed more reliably, so that it bends outwards in a spreading direction in the direction of the vehicle width.

[0063] Furthermore, in the present embodiment, a projecting flange section (projecting section) is provided in an upper part of the longitudinal member located above the through holes 21c and 21d. In this example, a projecting flange section 11e1 is provided on a front section of the upper flange part 11e of the front inner element 11. This can increase the stiffness of the section in which the projecting flange section 11e1 is provided, thereby facilitating the deformation of the sections in which the through holes 21c and 21d are formed.

[0064] Furthermore, as described above, the strut 19 extends in the vertical direction of the vehicle, with the strut 19 having a lower portion connected to the engine frame 45, and the front end of the engine frame 45 being located on the front of the vehicle near the parts with differing stiffness 21 and 22. In this example, the lower section of the front portion 19a of the strut 19 is connected to a front portion of the side frame part 45b of the engine frame 45. Additionally, the front portion of the side frame part 45b of the engine frame 45 is located further on the front of the vehicle than the parts with differing stiffness 21 and 22.

[0065] When an impact load acts on the front of the vehicle, as described above, the rearward impact load acts on the front section of the side frame member 45b of the engine frame 45, and then on the front part of the front longitudinal member 10. That is, a force acts that moves the engine frame 45 rearward within the vehicle before the load acts on the front longitudinal member 10. Therefore, the stress is concentrated on the parts 21 and 22 with different stiffness. This allows the impact load to be transmitted more reliably through the parts with different stiffness 21 and 22, and the impact energy can therefore be absorbed by the parts with different stiffness 21 and 22. It is also possible to adjust the position of the engine frame 45 so that the load is slightly concentrated on the parts with different stiffness 21 and 22.

[0066] Furthermore, in the present embodiment, the electric motor 1 has a front end that is positioned further rearward in the vehicle than the front ends of the parts with different stiffnesses 21 and 22, and the front end of the motor frame 45 is positioned in the vehicle in front of the front end of the front longitudinal member 10. In this example, the parts with different stiffnesses 21 and 22 are positioned further forward in the vehicle than the electric motor 1, as shown in Fig. Figure 5 shows that the front sections with low stiffness 21a and 22a, located beneath the sections with low stiffness 21a and 22a of the parts with different stiffnesses 21 and 22, are positioned further forward in the vehicle than the electric motor 1. With this arrangement, a certain amount of impact energy is absorbed by the parts with different stiffnesses 21 and 22, and the impact load is then transferred to the electric motor 1. That is, since the load is transferred to the electric motor 1 in a state where the impact energy has been reduced by the impact load, the protective effect for the electric motor 1 can be increased.

[0067] Since in the present embodiment the front end of the engine frame 45 is arranged in front of the front end of the front longitudinal member 10 in the vehicle, the front end of the engine frame 45 is also arranged in front of the parts with different stiffness 21 and 22 in the vehicle.

[0068] When an impact load acts on the front of the vehicle and the parts with different stiffnesses 21 and 22 are compressed, a force acts on the motor frame 45 that tends to move it towards the rear of the vehicle. Therefore, the motor frame 45 moves towards the rear of the vehicle by an amount corresponding to the compression of the parts with different stiffnesses 21 and 22 (within a range where the parts can be compressed). This protects the electric motor 1 and its peripheral components.

[0069] Since the engine frame 45 is shifted towards the rear of the vehicle, a load is concentrated on the front parts of the front longitudinal member 10 (parts with different stiffness 21 and 22), and the deformation mode can be easily controlled.

[0070] Additionally, the parts with different stiffnesses 21 and 22 have a concave section and a convex section oriented in the front-to-rear direction of the vehicle, with the concave section being the low-stiffness section 21a and the convex section being the high-stiffness section 21b. Since the concave section is the low-stiffness section 21a, it can be deformed to compress it. Furthermore, since the low-stiffness section 21a, which is the concave section, is located on the inner section of the front part of the front longitudinal member 10, it can be used as a starting point for bending the weak part 25 outwards. This allows the front longitudinal member 10 to be deformed in the intended deformation mode.

[0071] Furthermore, the weak part 25, as described above, is provided on the middle part in the front-rear direction of the vehicle in an inner part of the front longitudinal member 10 in the direction of the vehicle width, is recessed outwards in the direction of the vehicle width and extends in the vertical direction of the vehicle, so that it is possible to cause a deformation in which the weak part 25 bends convexly outwards in the direction of the vehicle width.

[0072] Furthermore, the front longitudinal member 10 of the present embodiment comprises, as shown in Fig. Figure 2 shows the front inner element 11 (front element), which extends in the front-to-rear direction of the vehicle, and the rear inner element 12 (rear element), which is connected to the rear part of the front inner element 11 and extends from the rear to the rear of the vehicle. The parts with differing stiffness 21 and 22 and the weak part 25 are provided in the front inner element 11. Furthermore, as described above, the rear inner element 12 consists of a high-tensile-strength steel plate and has a higher stiffness than the front inner element 11.

[0073] As a structure that increases the stiffness of the rear section more than that of the front section of the longitudinal beam 10, the rear section is also formed from an element with high stiffness, but is not limited to this. The stiffness can be increased, for example, by enlarging the cross-sectional shape of the rear section. Furthermore, the stiffness can be increased by providing a reinforcing structure, such as a ribbed structure, on the rear section.

[0074] Since, in the present embodiment, the inner part with differential stiffness 21 and the weak part 25 are provided in the front inner element 11, the load is transferred to both the inner part with differential stiffness 21 and the weak part 25, and the inner part with differential stiffness 21 and the weak part 25 can deform as intended. Furthermore, since the weak part 25 extends from the upper end to the lower end of the front inner element 11, as shown in Fig. As shown in Figure 2, the weak part 25 can be more reliably deformed to bend outwards, and the deformation mode can be achieved as intended.

[0075] Since the weak part 25 is deformed to bend outwards, the front longitudinal member 10 is also deformed away from a device such as the electric motor 1, which is located in the vehicle in front of the dashboard 51, and from a wiring harness or line carrying high voltage. Therefore, the front longitudinal member 10 can be prevented from pressing on or damaging the device or the like. Additionally, in the present embodiment, the front longitudinal member 10 is located below a skirt longitudinal member 52, which extends forward in the vehicle from an outer part of the strut tower 31 in an outer part of the dashboard 51 in the direction of the vehicle width, so that the skirt longitudinal member 52 cannot easily prevent the weak part 25 from deforming in such a way as to bend outwards.

[0076] Additionally, the front structure of the present embodiment, as described above, comprises the strut tower 31 and the subframe 35, as described above. As in Fig. 1, Fig. 7 and Fig. As shown in Figure 8, the strut tower 31 is connected to each of the front longitudinal members 10 on opposite sides in the direction of the vehicle width and extends in the vertical direction of the vehicle.

[0077] As in Fig. As shown in Figure 1, the strut tower 31 is located in the front of the vehicle on the outer part of the instrument panel 51, extending towards the vehicle's width. The strut tower 31 is made of a metal material and comprises an inner part 31a, a front part 31b, and a top part 31c. The inner part 31a has a wall surface that faces inwards towards the vehicle's width. A flange is provided on a rear section of the inner part 31a, which is connected to the instrument panel 51 by spot welding.

[0078] The front section 31b has a wall surface that extends outwards from a front section of the inner section 31a in the direction of the vehicle width. The subframe 35 is connected to the front section 31b. Furthermore, the inner section 31a and the front section 31b are formed as a single piece. The top section 31c is a separate element from the inner section 31a and the front section 31b and is connected to an upper section of the inner section 31a and an upper section of the front section 31b.

[0079] Inside the strut tower 31, i.e., in a space outside the inner part 31a in the direction of the vehicle width, a coil spring, a shock absorber, and the like are arranged, forming a suspension. An upper part of the shock absorber is attached to the upper part 31c. The strut tower 31 exhibits high rigidity, particularly in the vertical direction of the vehicle, and is capable of effectively absorbing a load transmitted by the shock absorber or the like.

[0080] As in Fig. As shown in Figure 1, the subframe 35 is an element that extends from the strut towers 31 in the direction of the vehicle width at the front of the vehicle to connect the strut towers 31 on opposite sides, and is made of a metal material. In this example, the subframe 35 comprises a central element 36 arranged in a middle section in the direction of the vehicle width, and outer extension elements 37 arranged outside the central element 36 in the direction of the vehicle width.

[0081] The central element 36 is a part that extends in the direction of the vehicle width and is located in the vehicle at a distance in front of the instrument panel 51. Each outer extension element 37 is connected to an outer end of the central element 36 in the direction of the vehicle width. The outer extension element 37 extends outward from the outer end of the central element 36 in the direction of the vehicle width to a point corresponding to the outer part of the front longitudinal member 10, and extends from this point inclined upwards as it runs rearward in the direction of the vehicle width. A flange is provided in a rear portion of the outer extension element 37, and the flange is connected by spot welding to the front portion 31b of the strut tower 31. Furthermore, an outer end of the outer extension element 37 is connected to the skirt longitudinal member 52. As shown in Fig. 2 and Fig. As shown in Figure 6, a lower part of the outer extension element 37 is arranged at intervals from the upper part 11c of the front inner element 11 of the front longitudinal member 10 and from the upper part 12c of the rear inner element 12. Additionally, the outer extension element 37 is arranged above the weak part 25, as shown in Figure 6. Fig. 2 shown.

[0082] For example, an electrical component is attached to the subframe 35. Since the subframe 35 is connected to the skirt longitudinal member 52 and the strut tower 31, the electrical component can be securely mounted. Because the subframe 35 and the front longitudinal member 10 are positioned with a gap between them, the subframe 35 is prevented from reducing the deformation of the front longitudinal member 10.

[0083] Furthermore, in the present embodiment, the engine frame 45 is connected to the front longitudinal member 10 via the mounting bracket 48, as shown in Fig. 2 shown, and the fastening bracket 48 is connected below the weak part 25. As shown in Fig. As shown in Figure 4, the fastening bracket 48 has a box shape with an opening on the top and is made of a metal material.

[0084] Additionally, in the present embodiment, as in Fig. 7 and Fig. Figure 8 shows the floor panel 53 of the vehicle compartment arranged further rearward in the vehicle than the front longitudinal member 10, and a reinforcing plate 18, extending in the direction of the vehicle width, is connected to the front part of the floor panel 53. The lower cross member 40, extending in the direction of the vehicle width, is connected below the reinforcing plate 18, and the inner curved element 14 and the outer curved element (a rear part of a rear element) are connected below the reinforcing plate 18.

[0085] The description of the present embodiment is an exemplary description of the present invention and does not limit the invention as claimed in the claims in any way. Furthermore, the configuration of the parts of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope as claimed in the claims.

[0086] For example, in the present embodiment, the inner part with varying stiffness 21 is provided on each of the inner wall parts 11a, which are arranged above and below the inner recess part 11b in the front part of the front inner element 11, but are not limited to this. For example, the inner part with varying stiffness 21 can also be provided on the inner recess part 11b. [List of reference symbols] 1 electric motor 10 Front longitudinal beams (side element) 11 front inner element (front element) 11a Interior wall section 11b inner recess part 11c Top part 11d Subside part 11e upper flange part 11e1 protruding flange part (protruding part) 11f lower flange part 12 rear inner element (rear element) 12a Interior wall section 12b inner recess part 12c Top part 12d bottom part 12E upper flange part 12f lower flange part 13 outer element 13b outer recess part 13f outer flange part 14 inner curved element 14a Interior wall section 14d Subside part 14g outer flange part 14h inner flange part 15 outer curved element 19 strut 19a Front part 19b Inner part (extension part) 21 inner part with different stiffness (part with different stiffness) 21a Section with low stiffness 21b section with high stiffness 21c long through hole 21d round through hole 22 outer part with different stiffness (part with different stiffness) 22a Section with low stiffness 22b section with high stiffness 25 weak part 31 Strut tower 31a inner part 31b Front part 31c Top part 35 subframes 36 central element 37 outer extension element 40 lower crossbeam 45 engine frame 45a Frame body part 45b side frame part 45c Body coupling part 45d shaft element 48 mounting brackets 51 Dashboard 52 apron longitudinal beams 53 Floor plate 55 side skirts QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2016-150685 A

[0006]

Claims

Front structure for an electric vehicle, comprising: longitudinal members arranged on opposite sides in a width direction of the vehicle in a front part of the vehicle and extending in a front-to-rear direction of the vehicle, and a motor frame arranged under each of the longitudinal members in the vehicle and supporting an electric motor, characterized in that: on a front part in an inner part of the longitudinal member in the direction of the vehicle width, a part with varying stiffness is provided, in which several sections with low stiffness and several sections with high stiffness, which have a higher stiffness than the sections with low stiffness, are arranged alternately in the front-to-rear direction of the vehicle; and on the longitudinal member in the vehicle behind the part with varying stiffness, a weak part is provided which has a lower stiffness than the parts with high stiffness. Front structure for the electric vehicle according to claim 1, wherein the longitudinal member has an inner wall part directed inwards in the direction of the vehicle width and an outer wall part arranged outwards from the inner wall part in the direction of the vehicle width, the part with differential stiffness is provided on each of a front section of the inner wall part and a front section of the outer wall part, and the positions of a low-stiffness section and a high-stiffness section of the part with differential stiffness on the inner wall part correspond to the positions of a low-stiffness section and a high-stiffness section of the part with differential stiffness on the outer wall part in the front-rear direction of the vehicle. Front structure for the electric vehicle according to claim 1, further comprising a strut covering a front end part of the longitudinal member, wherein an extension part is provided on an inner part of the strut in the direction of the vehicle width, which extends rearward in the vehicle, and the extension part is connected to the longitudinal member. Front structure for the electric vehicle according to claim 1, wherein on an outer section in the direction of the vehicle width in a front part of the longitudinal member an outer flange part is provided which projects in the direction of the vehicle width, and the strut is connected to the outer flange part, and a through hole is formed in the part with different stiffness of the longitudinal member. Front structure for the electric vehicle according to claim 4, wherein a projecting section is provided in an upper part of the longitudinal member, which is located above the through-hole, which projects upwards. Front structure for the electric vehicle according to claim 3, wherein the strut extends in the vertical direction of the vehicle, the strut has a lower part which is connected to the motor frame, and a front end of the motor frame is arranged at the front of the vehicle near the part with different stiffness. Front structure for the electric vehicle according to claim 1, wherein the electric motor has a front end that is arranged further rearward in the vehicle than a front end of the part with different stiffness, and the front end of the motor frame is arranged in the vehicle in front of a front end of the longitudinal member. Front structure for the electric vehicle according to one of claims 1 to 7, wherein in the part with different stiffness concave sections and convex sections are aligned in the front-rear direction of the vehicle, wherein the concave sections form the sections with low stiffness and the convex sections form the sections with high stiffness. Front structure for the electric vehicle according to one of claims 1 to 7, wherein the weak part is provided on a central part in the front-rear direction of the vehicle in an inner part of the longitudinal member in the direction of the vehicle width, is excluded in the direction of the vehicle width and extends in a vertical direction of the vehicle.

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