JP7585838B2 - Vehicle front structure - Google Patents

Description

The present invention relates to a vehicle front structure.

There is a demand for a vehicle front structure that is effective against a frontal collision in which the impact force is input to the outside of the side member, a so-called small overlap collision (sometimes called a small offset collision). This is because research into actual collision types shows that small overlap collisions occur frequently. Vehicles are equipped with a structure (crushable zone) that absorbs the collision energy by crushing part of the vehicle body during a collision, but in a small overlap collision, the vehicle body is difficult to crush. This is because in a small overlap collision, the collision load is input to the outside of the side member, so there is less of a part that is crushed.

The following Patent Document 1 discloses a vehicle front structure that takes small overlap collisions into consideration. The structure disclosed in Patent Document 1 aims to reduce damage to the front of the passenger compartment space (survival space) caused by the front wheels that are pushed backward against the vehicle body by an obstacle (another vehicle, a wall, etc.) during a small overlap collision. The vehicle disclosed in Patent Document 1 has a ladder frame structure, and a cabin is mounted on the ladder frame. A cab bracket that mounts this cabin protrudes laterally from the side member (side rail) of the ladder frame, and an inclined member that extends from the front to the rear from the inside of the vehicle body toward the outside is provided on the front of the cab bracket. The front wheels that are pushed backward against the vehicle body during a small overlap collision are deflected to the side and outward by this inclined member, reducing damage to the front of the passenger compartment space (cabin) caused by the front wheels. In addition, by pushing the front wheels to the side and outward, the collision load input to the side member via the front wheels is also reduced.

Patent No. 6052226

However, the vehicle front structure disclosed in Patent Document 1 only takes into account the behavior of the front wheels in a plan view, and does not take into account the possibility that the front wheels may be flipped upward by the inclined members. If the front wheels are flipped upward, a load may be input to the front of the vehicle interior space via the wheel house or front fender. The object of the present invention is to provide a vehicle front structure that can more reliably reduce the collision load input to the vehicle body via the front wheels during a small offset collision.

The vehicle front body structure according to the present invention includes a tire control bar and a tire catcher. The tire control bar extends outward from the side member and is positioned in front of the front wheels and above the center of rotation of the front wheels. The tire catcher extends outward from the side member and is positioned behind the front wheels. The tire catcher includes an inclined surface at its front that faces downward and forward.

The present invention makes it possible to more reliably reduce the collision load input to the vehicle body through the front wheels during a small offset collision.

1 is a plan view of a vehicle front structure according to an embodiment (vehicle static state). FIG. FIG. 2 is a side view of the vehicle front structure (vehicle static state). FIG. 2 is a perspective view of a tire control bar in the vehicle front structure. FIG. 2 is a perspective view of a tire catcher in the vehicle front structure. FIG. 4 is a plan view of the vehicle front structure (first stage of collision). FIG. 4 is a side view of the vehicle front structure (first stage of collision). FIG. 4 is a plan view of the vehicle front structure (second stage of collision). FIG. 4 is a side view of the vehicle front structure (second stage of collision). FIG. 4 is a plan view of the vehicle front structure (third stage of collision). FIG. 4 is a side view of the vehicle front structure (third stage of collision). FIG. 4 is a plan view of the vehicle front structure (fourth collision stage). FIG. 4 is a side view of the vehicle front structure (fourth collision stage). FIG. 4 is a plan view of the vehicle front structure (fifth collision stage). FIG. 4 is a side view of the vehicle front structure (fifth stage of collision).

The vehicle front structure according to the embodiment will be described with reference to the drawings. The vehicle front structure according to the embodiment controls the behavior of the front wheels 3 during a small overlap collision. First, the configuration of the vehicle front structure will be described based on the vehicle static state (stopped state) shown in Figures 1A and 1B.

The vehicle front structure of this embodiment is a front structure for a pickup truck having a ladder frame structure, and is equipped with a pair of side members 1 (also called side rails). Each side member 1 has a rectangular closed cross section. Figures 1A and 1B show the left half of the vehicle, and the right half is constructed symmetrically. A cabin (not shown) is placed on the front of the ladder frame including the side members 1, and a cargo bed (not shown) is placed on the rear.

The front portion of the side member 1 is positioned above (see FIG. 1B) and inside (see FIG. 1A) its rear portion. That is, the front portion of the side member 1 comprises a lower portion (outer portion) 1L, an upper portion (inner portion) 1U, and a transition portion 1T that smoothly connects the lower portion 1L and the upper portion 1U. The lower portion 1L and the upper portion 1U are formed linearly, but the transition portion 1T is formed curved in order to smoothly connect the lower portion 1L and the upper portion 1U. Note that in order to avoid contact with the front wheels 3 being steered, the upper portion (inner portion) 1U is positioned inside the lower portion (outer portion) 1L.

A front bumper reinforcement 6 is attached to the tip of the upper portion 1U via a weak portion 1X. The weak portion 1X is formed so as to be crushed by a frontal collision load to absorb the collision energy, and is also called a crash box. The weak portion 1X (crash box) has multiple beads formed at right angles to the front-to-rear direction of the vehicle to facilitate crushing. The weak portion 1X (crash box) may be formed as a separate part, or may be formed integrally with the front end of the side member 1.

The front wheel 3 described above is attached to the side member 1 (upper part 1U) via a conventional front suspension 2. There are various types of suspension, but the front suspension 2 in this embodiment is primarily a double wishbone suspension with upper arms 2U and lower arms 2L that can swing up and down. A hub carrier (not shown) is attached between the upper arms 2U and lower arms 2L, and the front wheel 3 is rotatably attached to a hub (not shown) held by the hub carrier.

The front suspension 2 also includes a bracket 2A fixed to the side member 1. A damper (not shown) and a coil spring (not shown) are attached between the lower arm 2L and the bracket 2A. The hub carrier is also provided with a knuckle arm (not shown), to which the tip of a tie rod (not shown) of a steering gear box is connected. The vehicle of this embodiment is a four-wheel drive vehicle, and is connected to a power plant (internal combustion engine and transmission: not shown) mounted at the front of the vehicle by a drive shaft (not shown). The outer end of the drive shaft is attached to the front wheels 3, and the inner end is connected to a front differential unit integrated with the transmission. The rear wheels are connected to the power train via a propeller shaft, a rear differential unit, and a drive shaft.

The vehicle front structure of this embodiment further includes a tire control bar 4 and a tire catcher 5 to control the behavior of the front wheel 3 during a small overlap collision. The tire control bar 4 is cantilevered outward from the outer surface of the weakened portion 1X of the side member 1 described above, and its tip is a free end. In other words, the tire control bar 4 is located forward of the front wheel 3 and behind the front bumper reinforcement 6. As shown in FIG. 3, the tire control bar 4 is bent upward midway and then bent again to become horizontal. The base end portion of the tire control bar 4 is formed as a front end cab mount bracket 4X that supports the lower front corner of the cabin from below.

The tire control bar 4 basically has a rectangular closed cross section, but the diagonally extending central part and the horizontally extending outer part have inclined surfaces 4S facing downward toward the rear. The part where the inclined surfaces 4S are formed has a closed pentagonal cross section. The inclined surfaces 4S are located in front of the front wheel 3 in a straight-ahead state. The tip of the tire control bar 4 also protrudes at least outward from the tire center plane. The tire center plane is a plane perpendicular to the rotation center axis O, including the center of the width of the front wheel 3 on the rotation center axis O of the front wheel 3 (the rotation center of the front wheel 3). Note that, because the front wheel 3 has a toe angle and a camber angle set, the tire center plane CP is slightly inclined and not perpendicular to the horizontal plane.

The tire control bar 4 (particularly the portion located in front of the front wheel 3 in a straight-ahead state) is located above the center of rotation of the front wheel 3 described above. In this embodiment, the tire control bar 4 extends outward from the outer surface of the upper portion 1U, which is located above the lower portion 1L. Furthermore, the outer portion of the tire control bar 4 itself is located above the base end portion. Therefore, the tire control bar 4 (particularly the portion located in front of the front wheel 3 in a straight-ahead state) is located sufficiently above the center of rotation of the front wheel 3 described above. However, the tire control bar 4 is not located above the top of the front wheel, and is preferably located at a height approximately halfway between the center of rotation of the front wheel 3 and the top.

On the other hand, the tire catcher 5 extends outward from the outer surface of the transition portion 1T of the side member 1 described above. In other words, the tire catcher 5 is located rearward of the front wheel 3. The tire catcher 5 is formed using a front pillar cab mount bracket 5X that supports the lower part of the front pillar of the cabin from below. A rear pillar cab mount bracket (not shown) that supports the lower part of the rear pillar of the cabin from below is also provided on the side member 1. The front part (front surface) of the tire catcher 5 is formed with an inclined surface 5S that faces forward and downward. Here, the lower edge of the inclined surface 5S is located below the above-mentioned center of rotation of the front wheel 3.

As described above, the tire catcher 5 extends outward from the transition portion 1T. Since the transition portion 1T is curved inward in a plan view, the width of the inclined surface 5S in the vehicle width direction can be made long. In this embodiment, the front edge of the tire catcher 5 is located at approximately the same height as the center of rotation of the front wheel 3. Since the front pillar cab mount bracket 5X is located approximately below the front pillar of the cabin, a passenger compartment is formed behind the tire catcher 5. A box-shaped member is welded to the front underside of the plate-shaped front pillar cab mount bracket 5X to form a closed cross section so that the tire catcher 5 is not easily crushed or dropped off from the side member 1 by a collision load from the front. The box-shaped member is also welded to the side of the side member 1.

Next, referring to Figures 4A to 8B, the behavior of the front wheel 3 that is thought to occur during a small overlap collision in the vehicle front structure having the above-mentioned configuration will be described. Note that here, a small overlap collision with an obstacle X will be described, and the obstacle X will be described as an example of an object that hardly moves after a collision (e.g., a wall). Note that in Figures 4A to 8B, the elastic deformation (deflection) of the tire of the front wheel 3 is not accurately depicted. For convenience, the tire is shown in a static state. As described above, in a small overlap collision, the obstacle X collides with the vehicle outside the side member 1. In other words, this is a type of collision in which the side member 1 cannot fully receive the impact load, and the vehicle body frame structure cannot fully absorb the collision energy.

Figures 4A and 4B show the initial stage of the collision (first collision stage). Since the vehicle collides with the obstacle X on the outside of the side member 1, the speed reduction due to the collision is small, and the vehicle continues to move forward due to inertia even after colliding with the obstacle X. As a result, the cantilevered tire control bar 4 is bent backward with respect to the vehicle body by the obstacle X and contacts the upper part of the front wheel 3 (other parts such as a fender liner may be interposed between the two). The front wheel 3 is pressed downward from the upper front by the tire control bar 4, that is, against the road surface. The above-mentioned inclined surface 4S of the tire control bar 4 effectively presses the front wheel 3 downward. The front wheel 3 pressed downward (to the road surface) tries to stay in that position, but the vehicle body continues to move forward due to inertia.

5A and 5B show the next second stage of the collision. As mentioned above, the inside of the front wheel 3 is connected to the vehicle body by the tie rod, the suspension arms 2U and 2L, and the drive shaft. These connections do not come off during normal driving, but they can come off due to the impact of a collision. However, until the connection comes off, the front wheel 3, which tries to stay in that position, is pulled from the inside as the vehicle body moves forward due to inertia. Therefore, the front wheel 3 is steered in the toe-out direction while being pressed downward by the tire control bar 4. If the front wheel 3 comes into contact with the inclined part in the middle of the tire control bar 4, this steering in the toe-out direction is promoted. At this time, the connection between the tie rod and the knuckle arm may come off due to the collision. As a result, the front wheel 3 begins to be pulled down so that the outer surface faces upward.

6A and 6B show the next third stage of the collision. Even after the second collision state described above, the vehicle continues to move forward due to inertia. During this process, the front wheel 3 is further pulled down while being pressed downward by the tire control bar 4, and the connection with the vehicle body described above may be gradually released. The drive shaft also comes out on the differential unit side or the hub side. The front wheel 3 is pulled down as if it is caught up in the steering in the toe-out direction described above, and comes into contact with the inclined surface 5S of the tire catcher 5, which has moved forward together with the vehicle body moving forward due to inertia. Since the inclined surface 5S is facing forward and downward, the front wheel 3 is guided by the inclined surface 5S as the vehicle body moves further forward due to inertia, and is pushed below the tire catcher 5 by the obstacle X. Furthermore, due to the further inertial movement of the vehicle body forward, the tire control bar 4 will eventually be completely bent or broken.

7A and 7B show the next fourth stage of the collision. The front wheel 3, which is pulled down with its outer side facing up and guided downward by the tire catcher 5, is guided by the inclined surface 5S due to further inertial movement toward the front of the vehicle body and slips under the tire catcher 5. Since the lower edge of the inclined surface 5S is located below the center of rotation of the front wheel 3, the front wheel 3 is pushed sufficiently downward. 8A and 8B show the next fifth stage of the collision. Since there is also a side member 1 (transition part 1T) on the inside, the front wheel 3 is pushed under the tire catcher 5 (and the lower part 1L) in a nearly horizontal position. Depending on the collision type, it is possible that the front wheel 3 may fall outward so as to be separated from the vehicle body, but even in this case, the front wheel 3 is moved away from the cabin (vehicle interior space). As a result, damage to the front part of the cabin (vehicle interior space) by the front wheel 3 is avoided. Damage to the front part and lower part of the front door can also be avoided.

In the first collision mode, the tire control bar 4 extends from the weak portion 1X, which is easily deformed by the moment force transmitted through the tire control bar 4. Therefore, the tip of the tire control bar 4 is easily moved rearward. The weak portion 1X may be damaged even in a minor offset collision, but if the weak portion 1X is configured as a separate part called a crash box, it will be sufficient to replace only the crash box (and the tire control bar 4 extended from it). Repairs to the side member 1 in a minor collision can be avoided.

In addition, at the time of collision, the front wheels 3 may be steered, but in a small overlap collision at a large steering angle at low speed, the collision will not result in damage to the front of the passenger compartment. In a medium to high speed collision where damage to the front of the passenger compartment is possible, the steering angle is small, so the behavior of the front wheels 3 is controlled as described above. In addition, the vertical position of the vehicle body relative to the front wheels 3 at the time of collision may change slightly due to vehicle body pitching caused by road surface conditions and vehicle acceleration/deceleration. However, the tire control bar 4 is positioned above the center of rotation of the front wheels 3, and the inclined surface 5S of the tire catcher 5 also faces forward and downward, so the behavior of the front wheels 3 is controlled as described above.

According to this embodiment, the vehicle body front structure is configured with a tire control bar 4 and a tire catcher 5. The tire control bar 4 extends outward from the side member 1 and is disposed in front of the front wheel 3 and above the center of rotation of the front wheel 3. The tire catcher 5 extends outward from the side member 1 and is disposed behind the front wheel 3, and has an inclined surface 5S facing downward in front of it. Therefore, at the beginning of a small offset collision, the tire control bar 4 controls the front wheel 3 to be pulled down so that the outer surface faces upward, and then the tire catcher 5 controls the front wheel 3 to be pushed downward in the passenger compartment space. As a result, the collision load input to the vehicle body (particularly the front part of the passenger compartment space) through the front wheel 3 during a small offset collision can be more reliably reduced.

In this embodiment, the tire control bar 4 has an inclined surface 4S at its rear that faces downward and rearward. Therefore, the inclined surface 4S can more reliably press the front wheel 3 downward at the beginning of the collision. As a result, the behavior of the front wheel 3, which is pulled down so that its outer surface faces upward, can be more reliably controlled.

In this embodiment, the lower edge of the inclined surface 5S of the tire catcher 5 is positioned below the center of rotation of the front wheel 3. Therefore, the inclined surface 5S can reliably push the front wheel 3 further downward. In other words, the front wheel 3 can be moved farther away from the passenger compartment space, more reliably avoiding damage to the passenger compartment space (and the front door).

In this embodiment, the tire control bar 4 extends outward from the side of the weak portion 1X of the side member 1. Because the rigidity of the weak portion 1X is lower (than the main portion of the side member 1), the tire control bar 4 can be brought into contact with the upper part of the front wheel 3 more reliably and earlier in the initial stage of a collision. As a result, the behavior of the front wheel 3 being pulled down so that its outer surface faces upward can be realized more reliably and earlier.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the front suspension 2 was a double wishbone type, but this is not limited to this. Regardless of the suspension type, the behavior control of the front wheels 3 during the small overlap described above can be performed. This is because the connection by the suspension allows the wheels to move relative to the vehicle body (and to turn in the case of the front wheels), and so can come off in the event of a collision. Also, in the above embodiment, a drive shaft was connected to the front wheels 3. However, even if a drive shaft is not connected to the front wheels 3, such as in a FR vehicle, the behavior control of the front wheels 3 during the small overlap described above can be performed.

Furthermore, the above-mentioned inclined surfaces 4S and 5S are formed as inclined flat surfaces, but they may be formed as inclined curved surfaces. For example, if the tire control bar 4 is formed from a round bar, the outer peripheral surface of the lower rear side thereof will be an inclined curved surface facing downward toward the rear. That is, such an inclined curved surface can also realize the behavior of the front wheel 3 being pulled down so that the outer surface faces upward at the beginning of the collision, as with the above-mentioned inclined surface 4S. Similarly, the behavior of the front wheel 3 being pushed downward can also be realized with respect to the inclined surface 5S. Furthermore, in the above embodiment, the obstacle X is described as something that hardly moves after the collision (e.g., a wall). However, even if the obstacle X is something that can move after the collision (e.g., another vehicle), the vehicle body will continue to move forward due to inertia in a small overlap collision, so the behavior of the front wheel 3 can be controlled in almost the same way.

1 Side member 1X Weakened portion 3 Front wheel 4 Tire control bar 4S Inclined surface (of tire control bar 4) 5 Tire catcher 5S Inclined surface (of tire catcher 5) 6 Front bumper reinforcement O Rotational center axis (of front wheel 3)

Claims (4)

A vehicle front structure,
a tire control bar extending laterally outward from the side member and disposed in front of the front wheels and above the rotation center of the front wheels;
a tire catcher extending laterally outward from an outer surface of a portion of the side member that curves from the inner side to the outer side in the vehicle width direction and disposed behind the front wheel,
A vehicle front structure, wherein the tire catcher has, at its front portion, an inclined surface facing forward and downward. The vehicle front structure according to claim 1, wherein the tire control bar has a rearwardly and downwardly facing inclined surface at its rear. The vehicle front structure according to claim 1 or 2, wherein the lower edge of the inclined surface of the tire catcher is positioned below the center of rotation. The vehicle front structure according to any one of claims 1 to 3, wherein the tire control bar extends outward from the side of a weak part formed at the front end of the side member to which a front bumper reinforcement is attached.

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