JP6468430B2 - Body front structure - Google Patents

Description

  The present invention relates to a vehicle body front portion structure that disperses a collision load input from a front portion of a subframe.

  At the front of the vehicle body of the automobile (vehicle), there are provided a front side member extending forward of the passenger compartment and a sub-frame that is disposed below the front side member and supports a power unit, a suspension, and the like. . Recently, in order to attenuate the suspension input transmitted to the front side member, each end portion of the subframe and the front side member are fixed using elastic fixing portions. Many elastic fixing parts are provided with a cylindrical elastic mount part composed of rubber bushes at each end of the subframe, and the elastic mount part is fastened to the lower part of the front side member with a fastening member such as a bolt member. Thus, the sub frame is elastically fixed to the front and rear portions of the front side member.

In such a vehicle, the load at the time of frontal collision of the vehicle is received by the subframe and transmitted to the floor side member behind the front side member to reduce the collision load, so that the vehicle compartment side of the subframe, power unit, etc. The intrusion to is suppressed.
By the way, when the vehicle collides with the front and the subframe is pushed rearward, in the elastic fixing portion behind the subframe, the bolt member supporting the elastic mount portion falls down to the rear of the vehicle body with the front side member side as a fulcrum. Occur. When the bolt member falls backward, a tensile load in the pulling direction acts on the bolt member, so that the bolt member falls off from the elastic mount portion, and the subframe may drop off at the initial stage of the collision. If the subframe falls off at the initial stage of the collision, the collision load cannot be fully supported. For this reason, there is a problem that the collision load cannot be effectively reduced, and the amount of intrusion into the vehicle compartment side of the power unit, the subframe, or the like increases.

  Therefore, the elastic fixing part (elastic mount part) that supports the rear of the subframe is connected to the floor side member behind the front side member using a reinforcing member such as a stay, and the collision load applied from the front part of the subframe is applied to the floor side member. A structure for transmitting to the side has been proposed (see Patent Documents 1 and 2).

JP 2012-206653 A Japanese Patent No. 5597682

  By the way, depending on the structure of the vehicle body, the elastic fixing portion (elastic mounting portion) behind the subframe protrudes from the lower end of the front side member rear portion (kick-up portion). A step is formed between the lower end and the floor side member. When the step is generated, the reinforcing member that connects the elastic fixing portion (elastic mounting portion) and the side member is forced to have a bent shape that follows the step between the lower end of the elastic fixing portion and the floor side member.

In the case of such a reinforcing member, since the reinforcing member is easily deformed as much as it is bent in accordance with the level difference, a sufficient reaction force cannot be obtained with respect to the collision load from the front portion of the subframe. May not be reduced sufficiently. For this reason, the reinforcing member has to be increased in rigidity and strength by increasing the thickness of the material or changing the material.
However, simply increasing the rigidity and strength of the reinforcing member causes an increase in weight and cost, so there is room for improvement.

  Accordingly, an object of the present invention is to provide a vehicle body front structure that improves the yield strength of the elastic fixing portion at the rear of the subframe against a collision load at the time of a frontal collision with a simple configuration that suppresses an increase in cost and weight.

  An aspect of the present invention includes a side member having a front side member extending in the vehicle front-rear direction in front of the vehicle compartment, a floor side member extending in the vehicle front-rear direction below the vehicle compartment, and a lower side of the front side member. A sub-frame that supports the suspension member, an elastic fixing portion that is provided at a rear end portion of the sub-frame and is fixed to a lower portion of the front side member via an elastic mount portion, and a floor behind the elastic fixing portion and the sub-frame. And a reinforcing bracket for connecting the side member in the vehicle front-rear direction. One end of the reinforcing bracket is fixed to the lower end of the elastic mount portion and extends obliquely upward to the rear of the vehicle, and the other end is fixed to the floor side member. The first support leg and branched from one end of the first support leg to extend obliquely upward to the rear of the vehicle, and the branched end is different from the first support leg. A second support leg fixed to a member at the lower part of the chamber, a wall part provided to fill the space between the first support leg and the second support leg and to face the elastic mount part in the vehicle front-rear direction, and a wall part And a recess into which the elastic mount portion fits when the elastic mount portion tilts toward the rear side of the vehicle body.

  According to the present invention, it is possible to improve the yield strength of the elastic fixing portion at the rear portion of the subframe with a simple configuration that suppresses an increase in cost and weight.

The perspective view which shows each part of the vehicle body front part structure which concerns on one Embodiment of this invention. The perspective view which expands and shows the periphery of a reinforcement bracket. The perspective view of each part of the reinforcing bracket together with the elastic fixing part. Sectional drawing in alignment with the AA in FIG. Sectional drawing explaining the behavior of the reinforcement bracket at the time of the front collision of a vehicle.

Hereinafter, the present invention will be described based on an embodiment shown in FIGS.
FIG. 1 shows a vehicle body front structure which is a main part of the present invention. In FIG. 1, reference numeral 1 denotes a vehicle compartment portion in which a front seat, a rear seat (none of them are shown), and the like are arranged. The power unit accommodating part formed in the front part of the compartment part 1 is each shown (all are shown with the dashed-two dotted line).
As shown in FIG. 1, the vehicle has a pair of side member members 9 arranged at intervals in the vehicle width direction, extending in the vehicle front-rear direction from the front end portion to the rear end of the vehicle. The side member member 9 includes a front side member 17 extending in the vehicle front-rear direction in front of the vehicle compartment portion 1 and a floor side member 15 extending in the vehicle front-rear direction below the vehicle compartment portion 1.

  Below the compartment 1, the pair of floor side members 15, a pair of side sills 13 disposed on the outermost side of the compartment 1 on both sides in the vehicle width direction of the floor side members 15, and a front end portion of the side sill 13 And a front gusset 18 (corresponding to the gusset of the present application) for connecting between the floor side member 15 and the floor side member 15 is provided. Incidentally, both the side sill 13 and the floor side member 15 are constituted by closed cross-section members extending along the vehicle body longitudinal direction, and the front gusset 18 is constituted by a member extending in the vehicle width direction.

On the other hand, the front side member 17 extends forward from the front portion of the floor side member 15 via a kick-up portion 17a that bends in the vertical direction in front of the passenger compartment 1. A frame-shaped subframe 19 is disposed below the front side member 17.
For example, the sub-frame 19 is spanned between a pair of side frames 21 respectively disposed on the lower side from the front part to the rear part (behind the kick-up part 17a) of the front side member 17 and the front and rear parts of the same side frame 21. It is formed in a square frame shape having the front and rear frames 23a and 23b. Each part of the suspension member 11 of the front wheel 7 (an arm, a shock absorber, a spring, etc .: only a part is shown) is supported on both sides (vehicle width direction) of the sub-frame 19 to support the front wheel 7. Incidentally, for example, the rear frame 23b of the sub-frame 19 supports the rear portion of the power train by a mount member (none of which is shown). And each edge part of the front-back direction of each side frame 21 is elastically supported by the front side member 17 immediately above via the elastic fixing | fixed part 25 and 26, respectively.

  That is, the elastic fixing portion 26 on the rear side of the side frame 21 is a cylinder in which, for example, a bolt member 31 as a fastening member can be inserted into the rear end portion of the side rail 21 as shown in FIGS. An elastic mount portion 29 (vertical direction) is provided. Specifically, the elastic mount portion 29 includes, for example, as shown in FIGS. 2 to 4, an outer cylinder 33 coupled to the end of the side frame 21, an inner cylinder 34 through which the bolt member 31 is inserted, and an outer cylinder 33. And a rubber bush 35 provided between the inner cylinder 34 and the inner cylinder 34. Then, the bolt member 31 is inserted into the inner cylinder 34 of the elastic mount portion 29 from below, and the bolt member 31 is fastened to the lower portion of the front side member 17 directly above, specifically, the lower portion of the kick-up portion 17a. As a result, the rear end portion (elastic fixing portion 26) of the side frame 21 is fixed to the lower portion of the front side member 17. Similarly, the elastic fixing portion 25 at the front end of the side frame 21 is also fixed to the lower portion of the front side member 17 using the elastic mount portion 37, and the entire sub frame 19 is elastically supported by the front side member 17. Thereby, suspension input (vibration or the like) input from the suspension member 11 of the front wheel 7 can be prevented from being transmitted from the front side member 17 to the vehicle compartment 1 side. In addition, since the same structure as the elastic mount part 29 is used for the elastic mount part 37, it abbreviate | omits about a detailed structure.

A reinforcing bracket 39 (reinforcement) that connects the elastic fixing portion 26 and a member below the vehicle compartment portion 1 in the front-rear direction to the elastic fixing portion 26 at the rear end portion of the subframe 19, that is, the rear end portion of the side frame 21. Member).
The reinforcing bracket 39 receives a collision load from the front part of the subframe 19 at the time of a frontal collision of the vehicle and suppresses the falling of the elastic mount part 29 to the rear side. This is the part to be transmitted to the front gusset 18). The same structure is used for both left and right. Of these, the structure of the reinforcing bracket 39 on one side will be described as a representative example with reference to the perspective views of FIGS. 2 and 3 and the sectional view of FIG. 4 (A-A line in FIG. 2).

  As shown in FIGS. 2 to 4, the reinforcing bracket 39 is made of a sheet metal member, and has a V shape from the lower portion of the elastic mount portion 29 so as to connect the lower portion of the elastic mount portion 29 to the floor side member 15 and the front gusset 18. It has the V-shaped leg 41 extended in this. The V-shaped leg 41 has one end fixed to the lower end of the elastic mount portion 29 and the other end extending linearly from the lower portion of the elastic mount 29 toward the front end portion of the rear floor side member 15. And a second support leg 45 that branches in a V shape from the lower end of the elastic mount portion 29 and extends obliquely toward the front gusset 18, which is a member at the lower part of the vehicle compartment that is different from the first support leg 43. Yes. That is, the 1st support leg 43 and the 2nd support leg 45 are branched in the V shape where a space | interval gradually expands from one end part.

  Of these, the first support leg 43 is fixed to the lower end of the front side of the floor side member 15 provided at one end and a fixed seat 47 fixed to the lower part of the elastic mount 29 and the other end. The fixed seat portion 49 and the intermediate portion 51 extending continuously from the fixed seat portion 47 to the fixed seat portion 49 in a band shape are formed. The first support leg 43 is bent in the vertical direction by the difference in the height direction between the lower end of the elastic mount 29 and the lower end of the front side member 15 because the elastic mount 29 protrudes downward. It has a stepped shape. Specifically, the intermediate portion 51 is bent between the fixed seat portion 47 and the fixed seat portion 49 having different heights so as to be inclined in the vertical direction. That is, the intermediate portion 51 is formed so as to extend obliquely upward and rearward of the vehicle from the fixed seat portion 47 at one end portion toward the fixed seat portion 49 at the other end portion. Then, in a state where the fixed seat portion 47 is overlapped with the lower end of the elastic mount portion 29, the sub frame 19 (elastic mount portion 29) is fastened together by a bolt member 31 that fixes the front side member 17. It is fixed to the lower end. On the other hand, the fixed seat portion 49 is fixed to the lower end of the floor side member 15 behind the kick-up portion 17a by, for example, a bolt member 55. The fixed seat portion 47, the fixed seat portion 49, and the intermediate portion 51 are surrounded by a continuous flange portion 53, and the rigidity of the first support leg 43 is ensured.

  Further, the second support leg 45 is fixed to the lower end of the front gusset 18 provided at the branch end 57 branched from the fixed seat 47 in the form of a V shape with the first support leg 43. The fixed seat portion 59 and the intermediate portion 61 extending continuously from the branch portion 57 to the fixed seat portion 59 in a belt shape are formed. The second support leg 45 is also a step that is bent in the vertical direction by the difference in height between the lower end of the elastic mount 29 and the lower end of the front gusset 18 as the elastic mount 29 protrudes downward. It is made into a shape. Specifically, the intermediate portion 61 is bent between the fixed seat portion 47 and the fixed seat portion 59 having different heights so as to be inclined and extend in the vertical direction. That is, the intermediate portion 61 is formed to extend obliquely upward and rearward of the vehicle from the fixed seat portion 47 at one end toward the fixed seat portion 59. And the fixed seat part 59 is fixed to the lower end of the front gusset 18 with the bolt member 63, for example. Note that the periphery of the fixed seat portion 59 and the intermediate portion 61 is also surrounded by the flange portion 53, and the rigidity of the second support leg 45 is ensured.

In this way, the reinforcing bracket 39 has the V-shaped leg 41 composed of the first support leg 43 and the second support leg 45 branched in a V-shape, so that the collision load applied from the front portion of the subframe 19 is reduced. Via the first support leg 43 and the second support leg 45, it can be efficiently distributed and transmitted to the front gusset 18 on the floor side member 15 and the side sill 13 side.
In addition, the reinforcing bracket 39 continues to the subframe 19 even after it is deformed by a collision load (frontal collision) while suppressing the collapse of the elastic mount portion 29 of the elastic fixing portion 26 at the rear end portion of the subframe 19. The structure is devised so that it can continue to transmit the collision load to the front side member 15 and the side sill in response to the collision load from the front.

  That is, the wall portion 65 is provided between the V-shaped legs 41 of the reinforcing bracket 39, that is, between the first support legs 43 and the second support legs 45 branched in a V-shape. A recess 67 that is recessed toward the rear of the vehicle body is formed in the central portion of the wall portion 65.

  Specifically, as shown in FIGS. 2 and 3, the wall portion 65 is provided so as to fill a V-shaped open portion between the first support leg 43 and the second support leg 45 forming the V-shaped leg 41, for example. It is done. Here, the wall portion 65 is provided so as to block the region of the open portion from the top of the V-shaped open portion to the intermediate portion of the support legs 43 and 45. And the wall part 65 is provided so that it may incline in the up-down direction along the extension direction of the intermediate parts 51 and 61 of the 1st support leg 43 and the 2nd support leg 45. As shown in FIG. Thereby, the wall part 65 is arrange | positioned so that the elastic mount part 29 may be opposed in an outer peripheral direction. That is, the inclined wall portion 65 is provided so as to face the elastic mount portion 29 from the vehicle rear side.

  The concave portion 67 is provided near the fixed seat portion 47 in the wall portion 65, and is formed so that the concave portion gradually becomes deeper toward the fixed seat portion 47 side (lower side). The concave portion 67 is provided to face the elastic mount portion 29. Specifically, the recess 67 is formed as a recess that receives the lower corner portion 29a that is the outer peripheral edge of the elastic mount portion 29 when the elastic mount portion 29 is tilted rearward of the vehicle body. More specifically, the concave portion 67 is a collision load applied from the front portion of the subframe 19, and the support members 43 and 45 and the wall portion 65 are bent and deformed rearward of the vehicle body, and the bolt member 31 fixing the elastic mount portion 29 is formed. When the front side member 17 is tilted to the rear of the vehicle body by a predetermined amount with the fulcrum as a fulcrum, the lower corner portion 29a of the elastic mount portion 29 pushed out to the rear side of the vehicle body, that is, a recess having a size to fit the lower end edge of the outer cylinder 33 Is formed. For example, the concave portion 67 corresponds to the shape of the lower corner portion 29a (lower end edge portion of the outer cylinder 33) of the elastic mount portion 29 when tilted as shown in FIGS. It is formed with a semicircular recess that gradually increases in depth as it approaches. Incidentally, of the concave shape of the concave portion 67, 67a is a ridge line corresponding to the lower corner portion 29a of the elastic mount 29, 67b is a bottom surface corresponding to the lower surface of the lower corner portion 29a connected to the ridge line 67a, and 67c is the above-mentioned Side wall surfaces (side surfaces) corresponding to the outer peripheral surface of the lower corner portion 29a connected to the ridgeline 67a are shown.

  That is, when the reinforcing bracket 39 is deformed by the collision load and the elastic mount portion 29 (bolt member 31) is inclined by a predetermined amount toward the rear of the vehicle body, the lower corner portion 29a of the elastic mount portion 29 fits in the recess 67. The elastic mount portion 29 is fitted in the recess 67 so that the inclination (retreat) of the elastic mount portion 29 and the deformation of the reinforcing bracket 39 are suppressed. Thereby, the reinforcement bracket 39 obtains a reaction force against the collision load even after the deformation starts, and can receive the collision load for a longer period.

Next, the operation and effect of this embodiment at the time of frontal collision of the vehicle will be described with reference to FIGS. 4 and 5A and 5B.
For example, it is assumed that a collision load F <b> 1 is applied to the front part of the front side member 17 or the front part of the subframe 19 due to a frontal collision of the vehicle.
Then, the front side member 17 transmits to the floor side member 15 behind the kick-up portion 17a while absorbing the collision load F1 which is compressed and deformed from the front end portion.

On the other hand, the collision load F <b> 1 applied to the subframe 19 is a floor side member via the first support legs 43 and the second support legs 45 of the reinforcement bracket 39 that reinforces the elastic mount 29 at the rear end of the subframe 19. 15 and front gusset 18.
When the reinforcing bracket 39 cannot withstand the applied collision load F1, the intermediate portions 51 and 61 of the first support leg 43 and the second support leg 45 are curved backward as shown in FIG. Begin to transform. That is, the reinforcing bracket 39 begins to bend and deform backward. Due to the deformation of the reinforcing bracket 39, as shown in the two-dot chain line in FIG. 2 and FIG. 5A, the bolt member 31 has the first support leg 43 at the rear of the vehicle body as a fulcrum with the front side rail 17 side as a fulcrum. Tilt between the second support legs 45. That is, the elastic mount portion 29 is tilted rearward of the vehicle body and fits into the recess 67.

Specifically, the lower corner portion 29a of the elastic mount portion 29 pushed out to the rear of the vehicle body enters the recess 67, and is brought into contact with and caught by the side wall surface 67c. 5A indicates a state in which only the lower corner portion 29a and the wall surface portion near the ridge line 67a of the recess 67 are in contact with each other.
As the bending deformation of the reinforcing bracket 39 proceeds, the contact area of the elastic mount portion 29 with respect to the side wall surface 67c of the recess 67 gradually increases as shown in FIG. Thereby, the resistance of the reinforcement bracket 39 with respect to the elastic mount portion 29 is increased, and the retraction of the elastic mount portion 29 is suppressed by the reinforcement bracket 39. At the same time, the deformation of the reinforcing bracket 39 is further suppressed by the elastic mount portion 29. That is, the reinforcing bracket 29 can receive the collision load F1 while maintaining the reaction force even in the deformed state.

Therefore, since the reinforcing bracket 39 can obtain a reaction force against the collision load F1 for a while after starting to deform, the floor side member receives the collision load F1 from the front portion of the subframe 19 longer than the conventional one. 15 or the front gusset 18 on the side sill 13 side.
In particular, the region (contact area) where the outer peripheral surface of the elastic mount 29 and the side wall surface 67c of the recess 67 come into contact with each other increases as the deformation of the reinforcing bracket 39 progresses, so that the collision load F1 can be effectively absorbed. The collision load F1 is transmitted to the side rail 15 and the side sill 13. In addition, as the deformation progresses, the load application position also changes from the initial lowest α position to the β position approaching the front side rail 17 as shown in FIG. In addition, the bending moment applied to the elastic mount 29 can be suppressed. Thereby, the collision load F1 can be received by the reinforcing bracket 39 for a longer period of time, and the collision load F1 can be effectively reduced. That is, the yield strength of the elastic fixing portion 26 at the rear end portion of the subframe 19 can be improved.

In addition, the structure for transmitting the collision load F1 is such that the V-shaped open portion between the first support leg 43 and the second support leg 45 arranged in the V shape is closed by the wall portion 65, and the elastic mount portion is formed on the wall portion 65. It is only necessary to form the concave portion 67 for receiving 29, the structure is simple, and an increase in cost and weight can be minimized.
In addition, the concave portion 67 is an opening corresponding to a part of the lower corner portion 29a of the elastic mount portion 29, and the depth becomes closer to the fixed seat portion 47 (one end portion of the reinforcing bracket 39) of the V-shaped leg 41. Since the shape corresponding to the posture of the elastic mount part 29 that falls in advance, such as a gradually increasing dent shape, is set in advance, the elastic mount part 29 that falls can be most effectively received, and is most effective for transmitting the collision load F1. It is valid.

As described above, the collision load F1 acting on the sub-frame 19 can be effectively distributed and transmitted to the floor side member 15 and the side sill 13 with a simple configuration that suppresses an increase in cost and weight. The yield strength of the elastic fixing portion 26 at the rear end of the frame 19 can be improved.
It should be noted that the configurations and combinations thereof in the above-described embodiment are merely examples, and it is needless to say that additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention. Nor. Further, the present invention is not limited by the embodiment, and needless to say, is limited only by the “claims”.

1 Car compartment 9 Side member member 11 Suspension member 13 Side sill 15 Floor side member 17 Front side member 18 Front gusset (gusset)
19 Subframe 26 Elastic fixing portion 29 Elastic mounting portion 31 Bolt member 39 Reinforcing bracket 41 V-shaped leg 43 First support leg 45 Second support leg 65 Wall portion 67 Recessed portion

Claims (4)

A side member member having a front side member extending in the vehicle front-rear direction in front of the vehicle compartment and a floor side member extending in the vehicle front-rear direction below the vehicle compartment;
A subframe disposed below the front side member to support the suspension member;
An elastic fixing portion provided at a rear end portion of the subframe and fixed to a lower portion of the front side member via an elastic mount portion;
A reinforcing bracket for connecting the elastic fixing portion and the floor side member behind the subframe in the vehicle front-rear direction;
The reinforcing bracket is
A first support leg having one end portion fixed to the lower end of the elastic mount portion and extending obliquely upward rearward of the vehicle, and the other end portion fixed to the floor side member;
A second support leg that is branched from one end of the first support leg and extends obliquely upward to the rear of the vehicle, and the branched end is fixed to a member at the lower part of the vehicle compartment that is different from the first support leg;
A wall portion that fills a space between the first support leg and the second support leg and is provided to face the elastic mount portion in the vehicle front-rear direction;
A vehicle body front part structure comprising: a recess provided in the wall portion, into which the elastic mount portion is fitted when the elastic mount portion tilts toward the rear side of the vehicle body.   The vehicle body front part structure according to claim 1, wherein the concave portion is formed so as to gradually increase in depth as it approaches one end portion of the first support leg.   3. The vehicle body front structure according to claim 1, wherein the first support leg and the second support leg are branched in a V shape with a gap gradually increasing from the one end. 4. The lower part of the passenger compartment is
A side sill extending in the vehicle front-rear direction on the outside in the vehicle width direction of the floor side member;
A gusset that extends in the vehicle width direction at the front of the vehicle compartment and connects the floor side member and the side sill;
The vehicle body front part structure according to any one of claims 1 to 3, wherein the second support leg is fixed to the gusset.

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