JP6791000B2 - Suspension arm - Google Patents

Description

The present invention relates to a suspension arm mounted on a vehicle.

In a vehicle such as an automobile, there is a vehicle provided with a suspension arm as a member constituting a suspension device that supports the wheels. The suspension arm is provided in the suspension mechanism, for example, to control the movement of the front wheels. For example, Patent Document 1 describes a suspension arm provided in a suspension mechanism. The suspension arm described in Patent Document 1 is connected to a suspension member, and is configured to release the connection with the suspension member when the suspension arm receives a predetermined load due to a collision.

JP-A-2015-157539

The present inventor has obtained the following recognition about the suspension arm.
From the viewpoint of protecting the occupants in the cabin in the event of a vehicle collision, it is desired to reduce the collision load of the wheels on the cabin during a small overlap collision (small lap collision). For this reason, it is conceivable to control the trajectories of the tires and wheels (hereinafter referred to as wheels) in the event of a collision to reduce damage to the cabin.

In order to control the trajectory of the wheel, it is conceivable to add a structural member for disconnection to the front connecting portion of the suspension member with the suspension arm so that the front connecting portion is detached from the suspension member in the event of a collision. However, in this configuration, a structural member for detachment is additionally provided to the suspension member, and it is considered that the weight of the vehicle increases due to the added structural member and the manufacturing cost increases. It is also possible that the detachment load at the time of collision is not always stable.
From this, the present inventor has recognized that the suspension arm has a problem to be improved from the viewpoint of more reliably disconnecting the front connecting portion from the suspension member in the event of a collision.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a suspension arm capable of more reliably detaching the front connecting portion from the suspension member in the event of a collision.

In order to solve the above problems, the suspension arm of an embodiment of the present invention is a suspension arm interposed between a knuckle supporting the front wheels of a vehicle and a suspension member, and is a knuckle connecting portion connected to the knuckle. And a front connecting portion and a rear connecting portion connected to the suspension member. The front connecting portion is provided in front of the rear connecting portion in the front-rear direction of the vehicle, and the front connecting portion has a fragile portion so that the front connecting portion breaks when a collision load at the time of a vehicle collision is input to the front wheels. The fragile portion is provided and has a shape that extends along the vehicle front-rear direction and is recessed in the vehicle vertical direction in the vicinity of the base of the cylindrical portion of the front connecting portion, and is based on the center position of the cylindrical portion in the vehicle vertical direction. It is provided at a position closer to either side of the vehicle in the vertical direction, and the knuckle connecting portion is provided on the side opposite to the fragile portion with the center of the shearing force of the suspension arm in between when viewed in the vertical direction of the vehicle. ..

According to this aspect, since the moment load in the breaking direction acts on the fragile portion provided in the front connecting portion at the time of collision, it is possible to break the fragile portion more reliably.

According to the present invention, it is possible to provide a suspension arm capable of more reliably detaching the front connecting portion from the suspension member in the event of a collision.

It is a rear view of the suspension mechanism provided with the suspension arm which concerns on embodiment. It is a top view of the suspension mechanism of FIG. It is a top view of the suspension arm of FIG. It is a side view of the suspension arm of FIG. It is a side view which shows the periphery of the fragile part of the suspension arm of FIG. It is sectional drawing which cut along the AA line of the suspension arm of FIG. It is a schematic diagram explaining the state before the collision of the suspension arm of FIG. It is a schematic diagram explaining the state at the time of a collision of the suspension arm of FIG. It is a schematic diagram explaining the state in which the fragile portion of the suspension arm of FIG. 1 is broken.

The present inventor considered from the viewpoint of reducing the collision load on the cabin of the front wheels at the time of a small overlap collision (hereinafter, simply referred to as a collision), and obtained the following findings.
In order to reduce this collision load, it is conceivable to provide a fragile portion that is easily deformed by the collision load in the vicinity of the connecting portion of the suspension member with the suspension arm. In this case, if the suspension member has a fragile portion, the rigidity of the connecting portion in the vehicle width direction may decrease. Further, in order to reduce the collision load, it is conceivable to provide the suspension member with a structural member configured to be detached in the event of a collision. In this case, it is conceivable that the structural member for detachment causes an increase in weight and cost. Further, in order to reduce the collision load, it is conceivable to provide the suspension arm with a crimping portion that is plastically deformed and released when a load is applied to the front wheels. In this case, it is conceivable that the work man-hours for forming the crimping portion on the suspension arm will increase, and the detachment load may not be stable.

Therefore, the present inventor provides a fragile portion formed so that the connecting portion of the suspension arm to the suspension member breaks at the time of collision, and twists the fragile portion by applying a rotational moment to more reliably secure the fragile portion. I devised a configuration to break it. In this case, compared to a configuration in which a fragile portion is simply provided, the fragile portion can be easily broken by twisting the fragile portion, so that the rigidity of the fragile portion at the time of non-collision can be set higher. Become.
The embodiment was devised based on such thoughts, and its specific configuration will be described below.

Hereinafter, the present invention will be described with reference to each drawing based on a preferred embodiment. In the embodiments and modifications, the same or equivalent components and members are designated by the same reference numerals, and redundant description will be omitted as appropriate. In addition, the dimensions of the members in each drawing are shown enlarged or reduced as appropriate for easy understanding. In addition, some of the members that are not important for explaining the embodiment in each drawing are omitted and displayed.
Also, terms including ordinal numbers such as 1st and 2nd are used to describe various components, but this term is used only for the purpose of distinguishing one component from other components. The components are not limited by.

[Embodiment]
The suspension arm 10 according to the embodiment will be described with reference to each figure. FIG. 1 is a rear view schematically showing a suspension mechanism 100 including the suspension arm 10 according to the embodiment. FIG. 2 is a plan view schematically showing the suspension mechanism 100. In FIGS. 1 and 2, the description of members that are not important for explaining the embodiment is omitted. Hereinafter, the description will be given based on the XYZ Cartesian coordinate system. The X-axis direction corresponds to the front-rear direction of the vehicle, the Y-axis direction corresponds to the left-right width direction of the vehicle, and the Z-axis direction corresponds to the vertical direction of the vehicle. The Y-axis direction and the Z-axis direction are orthogonal to the X-axis direction, respectively.

The suspension mechanism of the vehicle includes a symmetrically configured mechanism that supports the left front wheel and the right front wheel, respectively. The suspension mechanism 100 is a mechanism that supports the left front wheel. The suspension mechanism 100 mainly includes a suspension arm 10, a suspension member 32, a ball joint 34, a knuckle 36, an axle 38, a wheel hub 40, a tire 42, a brake disc 44, and a strut mechanism 48. Including. The wheel hub 40 and the tire 42 are coupled to each other to form the front wheel 20.

The suspension member 32 is a skeleton that supports the links of the suspension mechanism 100. Suspension members are sometimes also referred to as subframes. The suspension member 32 supports the front connecting portion 14 and the rear connecting portion 16 inside the vehicle of the suspension arm 10. With this configuration, the outer portion of the suspension arm 10 in the X-axis direction is rotatably supported in the Z-axis direction with respect to the suspension member 32.

The ball joint 34 is composed of a ball stud (not shown) and a socket (not shown) that makes spherical contact with the ball stud (not shown). The ball joint 34 is interposed between the suspension arm 10 and the knuckle 36, and connects the knuckle 36 to the suspension arm 10. The lower end side of the ball joint 34 is fixed to the knuckle connecting portion 12 provided at the outer end portion of the suspension arm 10 on the vehicle side. The knuckle 36 is interposed between the suspension arm 10 and the strut mechanism 48 via a ball joint 34, and connects them. The knuckle 36 rotatably supports the axle 38 via a bearing (not shown).

The wheel hub 40 and the tire 42 are connected to the axle 38. The lower end of the strut mechanism 48 is connected to the upper part of the knuckle 36, and the upper end of the strut mechanism 48 is connected to the vehicle body. The suspension mechanism 100 configured in this way supports the front wheels 20 on the vehicle body together with other link members. When a vehicle collides with a small overlap, a load in the X-axis direction is input to the front wheels 20 from the front to the rear (from the top to the bottom in FIG. 2), and the loads are the axle 38, the knuckle 36, and the ball. It is transmitted to the knuckle connecting portion 12 of the suspension arm 10 via the joint 34. That is, a load from the front to the rear in the X-axis direction is input to the knuckle connecting portion 12 of the suspension arm 10 when a small overlap collision occurs.

(Suspension arm)
FIG. 3 is a plan view of the suspension arm 10 according to the embodiment. FIG. 4 is a side view of the suspension arm 10. FIG. 5 is a side view showing the periphery of the fragile portion 10 m of the suspension arm 10. The suspension arm 10 is interposed between the knuckle 36 supporting the front wheel 20 and the suspension member 32 in the suspension mechanism 100. The suspension arm 10 is configured to rotatably support the front wheels 20 up and down. The suspension arm is sometimes referred to as the lower arm.

The suspension arm 10 of this example mainly includes a first arm portion 10a, a second arm portion 10b, a knuckle connecting portion 12, a front connecting portion 14, and a rear connecting portion 16. A fragile portion 10 m is provided on the front connecting portion 14. The first arm portion 10a is an arm extending along the X-axis direction, which is the vehicle front-rear direction. The second arm portion 10b is an arm extending along the Y-axis direction, which is the vehicle width direction. The suspension arm 10 of this example has a substantially L-shape in a plan view by including the first arm portion 10a and the second arm portion 10b.

As shown in FIG. 4, the suspension arm 10 has a strip-shaped contour elongated in the Y-axis direction in a side view. The suspension arm 10 is not particularly limited in material and forming method as long as it can achieve the desired rigidity and weight. The suspension arm 10 of this example is formed from a steel plate by press working.

The front connecting portion 14 of this example is connected to the suspension member 32 on the front side of the rear connecting portion 16 (see also FIG. 2). The front connecting portion 14 may be connected to the suspension member 32 by, for example, a rubber columnar bush (not shown). The front connecting portion 14 may include a cylindrical portion 14b provided inside the vehicle in the Y-axis direction of the second arm portion 10b. The cylindrical portion 14b has a tube shape with openings provided on both sides in the X-axis direction. The front connecting portion 14 may be connected to the suspension member 32 by a cylindrical member (not shown) inserted into the cylindrical portion 14b. The cylindrical member may be made of an elastic material such as rubber.

The rear connecting portion 16 of this example is connected to the suspension member 32 on the rear side of the front connecting portion 14 (see also FIG. 2). The rear connecting portion 16 includes a coupling hole portion 16b formed at a rear end portion of the first arm portion 10a. The coupling hole portion 16b may be a circular hole in a plan view penetrating vertically. The rear connecting portion 16 may be connected to the suspension member 32 by a fastening member (not shown) via, for example, a rubber bush (not shown) fitted in the coupling hole portion 16b. The front connecting portion 14 and the rear connecting portion 16 are configured to serve as rotation fulcrums when the knuckle connecting portion 12 rotates up and down in a state of being connected to the suspension member 32.

The fragile portion 10m is a portion that is easily deformed by a collision load acting on the suspension arm 10 via the front wheel 20. The fragile portion 10m is provided at the front connecting portion 14 to separate the suspension arm 10 from the suspension member 32. The fragile portion 10m may be provided in the vehicle interior in the Y-axis direction of the second arm portion 10b near the base of the cylindrical portion 14b of the front connecting portion 14. As shown in FIG. 5, the fragile portion 10m of this example has a shape recessed in the Z-axis direction in the vicinity of the base of the cylindrical portion 14b.

The fragile portion 10m of the suspension arm 10 is configured to be easily deformed by a collision load input via a knuckle connecting portion 12 or the like. The suspension arm 10 is configured such that when the fragile portion 10m breaks, the cylindrical portion 14b of the front connecting portion 14 is separated from the second arm portion 10b. The dimension H and the shape dimension of the recess of the fragile portion 10 m can be set by simulation corresponding to a desired deformation load.

FIG. 6 is a vertical cross-sectional view of the suspension arm 10 cut along the line AA by a vertical plane. This figure shows a vertical cross section of the second arm portion 10b as viewed in the Y-axis direction, which is the longitudinal direction thereof. The vertical cross section of the suspension arm 10 includes a pair of raised portions 10f that are raised upward and a recess 10d that is recessed downward between the pair of raised portions 10f. Each raised portion 10f includes an edge portion 10e extending upward from the outer end and an arc-shaped portion extending inward from the upper portion of the edge portion. The recess 10d includes a central portion extending substantially flat laterally and a portion extending upward from both ends of the central portion and connecting to the inside of each raised portion 10f. The width of the recess 10d in the X-axis direction is set to be about twice the width of each raised portion 10f in the X-axis direction. One raised portion 10f, the concave portion 10d, and the other raised portion 10f are integrally and continuously formed of steel plates having substantially the same thickness. Therefore, the lower surface of each raised portion 10f has a concave shape that is recessed upward, and the lower surface of the concave portion 10d has a protruding shape that protrudes downward.

The fragile portion 10m is provided closer to any one side of the front connecting portion 14 in the vehicle vertical direction (Z-axis direction). In this example, as shown in FIGS. 4 and 5, the front connecting portion 14 is provided downward in the Z-axis direction. The knuckle connecting portion 12, which is a load input point, is provided on the side opposite to the fragile portion 10m with the center Q of the shearing force of the suspension arm 10 interposed therebetween. The center of the shearing force is a specific point at which the cross section is not twisted regardless of the direction of the load. In the suspension arm 10 of this example, as shown in FIG. 6, in the cross section of the second arm portion 10b, it is set to substantially the central portion in the X-axis direction and the Z-axis direction. The position of the center Q of the shearing force can be obtained by simulation. In this example, as shown in FIG. 6, in the AA cross section of the suspension arm 10, the center Q of the shearing force is offset downward from the load input center P from the knuckle connecting portion 12, which is the load input point. It is placed in position.

In the suspension arm 10 configured in this way, the input load F as shown by the arrow in FIG. 3 is applied to the knuckle connecting portion 12 by the collision load input to the front wheels. A counterclockwise moment load is applied to the fragile portion 10 m in accordance with the input load F and the effective length L of the second arm portion 10b.

Further, when the input load F is applied, as shown in FIG. 6, a clockwise rotational moment M is applied to the fragile portion 10 m in a side view. As described above, since the moment load in two directions is intensively applied to the fragile portion 10 m due to the collision load, the fragile portion 10 m is more reliably broken.

Next, with respect to the suspension arm 10 configured in this way, the behavior of the front wheels 20 when a collision load is input and the fragile portion 10 m is broken will be described with reference to FIGS. 7 to 9. FIG. 7 is a schematic view illustrating a state of the suspension arm 10 before the collision. FIG. 8 is a schematic view illustrating a state of the suspension arm 10 at the time of collision. FIG. 9 is a schematic view illustrating a state in which the fragile portion 10 m of the suspension arm 10 is broken.

In the state of FIG. 7, when an impact load is input to the front wheel 20, as shown in FIG. 8, the middle of the second arm portion 10b of the suspension arm 10 begins to deform, and at the same time, the collision load is applied to the fragile portion 10m. As a result, the moment load is applied intensively. When the fragile portion 10m is broken by intensively applying the moment load to the fragile portion 10m, the front connecting portion 14 of the suspension arm 10 is separated from the suspension member 32 as shown in FIG. When the front connecting portion 14 is disengaged, as shown by arrows G and E in FIG. 9, the front wheel 20 largely abducts with the rear connecting portion 16 as a fulcrum to absorb energy at the time of collision, and the front wheel 20 is stable. Then, it collides with the rocker 46 in a state of being inclined sideways. Alternatively, the brake disc 44 or the like is swept out to the outside of the vehicle by abducting a large amount. In this case, damage to the cabin can be suppressed as compared with the case where the front wheels 20 collide in the vertical direction.

The operation and effect of the suspension arm 10 according to the embodiment of the present invention configured as described above will be described.

The suspension arm 10 according to the embodiment is a suspension arm 10 interposed between the knuckle 36 supporting the front wheel 20 of the vehicle and the suspension member 32, and is a knuckle connecting portion 12 connected to the knuckle 36 and a suspension. The front connecting portion 14 and the rear connecting portion 16 connected to the member 32 are provided, the front connecting portion 14 is provided in front of the rear connecting portion 16 in the vehicle front-rear direction, and the front connecting portion 14 is provided at the time of a vehicle collision. A fragile portion 10 m formed so as to break the front connecting portion 14 when the collision load of the above is input to the front wheels is provided, and the fragile portion 10 m is provided on either side of the front connecting portion 14 in the vehicle vertical direction. The knuckle connecting portion 12 is provided on the opposite side of the fragile portion 10 m with the center of the shearing force of the suspension arm 10 interposed therebetween.

According to this configuration, a moment load in the breaking direction can be applied to the fragile portion 10 m of the front connecting portion 14 at the time of a collision, so that the fragile portion 10 m is easily broken as compared with the case where this moment load does not act. Can be made to. By breaking the fragile portion 10m, the suspension arm 10 can be abducted around the rear connecting portion 16 at the time of a small overlap collision to reduce the collision load on the cabin. That is, it is possible to convert the collision energy into the rotational motion of the suspension arm and absorb it to reduce the collision load acting on the cabin.

The above description has been made based on the embodiment of the present invention. It will be appreciated by those skilled in the art that these embodiments are exemplary and that various modifications and modifications are possible within the claims of the invention, and that such modifications and modifications are also within the claims of the present invention. It is about to be done. Therefore, the descriptions and drawings herein should be treated as exemplary rather than limiting.

Hereinafter, a modified example will be described. In the drawings and description of the modified examples, the same or equivalent components and members as those in the embodiment are designated by the same reference numerals. The description that overlaps with the embodiment will be omitted as appropriate, and the configuration different from the embodiment will be mainly described.

(First modification)
In the embodiment, an example in which the suspension arm 10 is formed from a steel plate by press working has been described, but the present invention is not limited to this. The suspension arm 10 may be formed from another material such as an aluminum alloy by another step. In this case, the weight of the suspension arm can be reduced.

(Second modification)
In the embodiment, an example in which the suspension arm 10 has an L-shape in a plan view has been described, but the present invention is not limited to this. The present invention may be applied to a suspension arm having a shape other than the L shape, such as a substantially A shape, a substantially H shape, and a substantially I shape.

(Third modification example)
In the embodiment, an example in which the suspension arm 10 constitutes a so-called strut type suspension mechanism has been described, but the present invention is not limited to this. The present invention may be applied to a suspension arm that constitutes a suspension mechanism other than the strut type, such as a multi-link type suspension mechanism.

According to the above-described modification, the same actions and effects as those of the respective embodiments are obtained.

Any combination of the above-described embodiments and the embodiments and modifications is also useful as an embodiment of the present invention. The new embodiments resulting from the combination have the effects of the combined embodiments and variants.

10 ... Suspension arm, 10a ... 1st arm, 10b ... 2nd arm, 12 ... Knuckle connection, 14 ... Front connection, 16 ... Rear connection, 20 ... Front wheel, 32.・ Suspension member, 34 ・ ・ Ball joint, 36 ・ ・ Knuckle, 100 ・ ・ Suspension mechanism.

Claims (1)

A suspension arm that is interposed between the knuckle that supports the front wheels of the vehicle and the suspension member.
A knuckle connecting portion connected to the knuckle and a front connecting portion and a rear connecting portion connected to the suspension member are provided.
The front connecting portion is provided in front of the rear connecting portion in the front-rear direction of the vehicle.
The front connecting portion is provided with a fragile portion so that the front connecting portion breaks when a collision load at the time of a vehicle collision is input to the front wheels.
The fragile portion has a shape that extends along the vehicle front-rear direction and is recessed in the vehicle vertical direction in the vicinity of the base of the cylindrical portion of the front connecting portion, and is based on the center position of the cylindrical portion in the vehicle vertical direction. It is installed at a position closer to either side of the vehicle in the vertical direction.
A suspension arm characterized in that the knuckle connecting portion is provided on the side opposite to the fragile portion with the center of the shearing force of the suspension arm interposed therebetween when viewed in the vertical direction of the vehicle .

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