JP6384524B2 - Car front lower arm structure - Google Patents

Description

  The present invention relates to a front lower arm structure of an automobile, and more particularly to a structure of a lower arm provided in a double wishbone type front suspension device.

  A double wishbone type front suspension device is normally provided with two arms, an upper arm and a lower arm positioned below the upper arm, as illustrated in Patent Document 1 below, both of which extend in the vehicle width direction. The vehicle body side end is pivotally attached to the vehicle body side frame, and the wheel side end is connected to a knuckle member that rotatably supports the wheel via a ball joint. It controls and regulates the movement of tires.

  A lower control arm (13) as a lower arm provided in a wheel suspension device of an automobile disclosed in Patent Document 1 includes a base end portion (13f, 13r) as a vehicle body side end portion on each of the front and rear sides, and a front base end portion. (13f) and a front arm portion extending so as to connect the end portion on the knuckle (9) side, and a rear arm extending so as to connect the base portion on the rear side (13r) and the end portion on the knuckle (9) side. Are provided. And in the lower control arm (13) of patent document 1, the bending part which protrudes back in the intermediate part of the front arm part among the front and rear arm parts for reasons such as preventing interference with the front wheel to be steered And the whole is formed in a substantially L shape in plan view (see FIG. 3 of Patent Document 1).

  In such a front lower arm structure, when a load is transmitted from the wheel via the knuckle member, stress is easily concentrated on the bent portion of the front arm portion, and it is difficult to ensure rigidity. For this reason, in patent document 1, the structure which connected and reinforced two reinforcement members extended from a rear side arm part in the bending part of a front side arm part can be seen (refer FIG. 3 of patent document 1).

  However, as in the front lower arm structure of Patent Document 1, if a plurality of reinforcing members are provided for reinforcement with respect to one bent portion, it is difficult to reduce the weight, but if the number of reinforcing members is simply reduced, the lower control arm (13). There was a possibility that the rigidity of the steel could not be secured, and there was room for improvement.

Japanese Patent No. 2813888

  Accordingly, an object of the present invention is to provide a front lower arm structure for an automobile capable of reducing the weight and rigidity of the lower arm provided in the front suspension device.

In the present invention, a vehicle body side shaft support portion that pivotally supports the vehicle body side is provided on each of the front and rear sides, and among these vehicle body side shaft support portions on the front and rear sides, a front vehicle body side shaft support portion and a knuckle side pivot support portion that pivots on a knuckle member A front lower arm structure of an automobile comprising a front arm portion extending between the rear arm portion and a rear arm portion extending between the rear vehicle body side pivot support portion and the knuckle side pivot support portion, wherein the lower arm is The front arm portion and the rear arm portion are substantially A-shaped in plan view extending in the vehicle width direction so that the front arm portion and the rear arm portion are opened forward and backward in the vehicle body side, and the shaft centers of the vehicle body side shaft support portions on the front side and the rear side are both in the vehicle longitudinal direction. The arm portion on one side of the front arm portion and the rear arm portion is connected to an imaginary straight line that linearly connects the knuckle side pivot support portion and the vehicle body side shaft support portion on the one side. Said one side is in the shape of a convex convex to the other side or Extends bypassing and music, the arm portion of the other side, with the knuckle-side pivot support part, is shaped connecting the vehicle body side bearing portions of the other side substantially linearly, the one The arm portion on the side is provided with a vertical wall portion extending in the vertical direction and a horizontal rib that is thinner than the vertical wall portion and protrudes in the front-rear direction. The vertical wall portion is connected to the one of the vertical wall portions. It is straightened and extended so as to be closer to the reference line in the vehicle width direction than the ridge lines of the front edge and the rear edge of the side arm portion.

  According to the said structure, light weight and rigidity can be made higher than the case where a vertical wall part is provided in the rear edge of a rear side arm part.

As an aspect of the present invention, the one arm portion is a rear arm portion, and one side is a rear side.
According to the above configuration, the steering angle and the suspension support rigidity can be compatible by applying to the rear arm portion where the inner wheel side wheel cut is large during steering.

  Further, as an aspect of the present invention, the vertical wall portion of the arm portion on one side is formed with a bent portion protruding to the other side, and the horizontal rib is provided on one side of the vehicle body side shaft support portion on the one side. The side edge of the horizontal rib extends from the side portion toward the other side so as to approach the vertical wall portion, and the vehicle body side shaft support portion on the one side from the other side portion of the bent portion The edge of the other side of the horizontal rib extends toward the other side of the vertical wall portion.

  According to the said structure, the rear side arm part which has a vertical wall part can be effectively reinforced with a horizontal rib, ensuring the clearance gap with a tire.

  As an aspect of the present invention, the vertical wall portion has a substantially S-shape in plan view having at least two bent portions, and the arm portion on the other side of the other arm portion in each of the two bent portions. The shaft support portion is connected to the connecting portion by a reinforcing member via the horizontal rib.

  According to the above configuration, the vertical wall portion can be straightened and reinforced efficiently.

  As an aspect of the present invention, both the front and rear vehicle body side shaft support portions have elastic bushes having an axis parallel to a vehicle longitudinal reference line extending in the front-rear direction. It is the same axis.

  According to the above configuration, the geometry does not change due to the tilt of the lower arm, and the cost can be reduced.

  According to the present invention, the lower arm provided in the front suspension device can be made lighter and more rigid.

The perspective view of the state which incorporated the suspension apparatus of the present Example in the vehicle Side view of the suspension device of this embodiment assembled in a vehicle Rear view of the suspension device of this embodiment assembled in a vehicle The perspective view which looked at the principal part of the state which incorporated the suspension apparatus of the present Example in the vehicle from the downward direction Plan view of the suspension device of this embodiment Bottom view of the suspension device of this embodiment Rear view (a) and bottom view (b) of the lower arm of this example Schematic of a state in which a conventional suspension system is incorporated in a vehicle

An embodiment of the present invention will be described in detail with reference to the drawings.
In the following description, in the drawings, arrow F indicates the front of the vehicle, arrow R indicates the rear of the vehicle, arrow IN indicates the inner side in the vehicle width direction, arrow OUT indicates the outer side in the vehicle width direction, and arrow U indicates Shown above the vehicle.

  Since the left and right front suspension devices 1 have a bilaterally symmetric shape and the same structure, the left front suspension device 1 will be described.

  As shown in FIG. 1, the front suspension device 1 of the present embodiment is attached to a front side frame 100 and a front subframe 101 provided at the front part of a vehicle body, and includes an upper arm 2 attached to the front side frame 100, a front It is a double wishbone type having a lower arm 3 attached to the subframe 101, a wheel support member 4 (also referred to as a wheel member or a knuckle member) attached to the upper and lower arms 2 and 3, and a shock absorber 5.

  The structure of the front part of the vehicle body to which such a front suspension device 1 is assembled will be briefly described with reference to FIGS. In addition, in FIGS. 1-4, the vehicle body front part structure of the vehicle body left side is shown typically.

The front side frame 100 is provided with a pair of left and right so as to extend forward from the lower end portion of a dash panel (not shown) serving as a partition wall that partitions a vehicle compartment and an engine compartment 110A (see FIG. 4) to be described later. The lower part of the suspension tower 102 (sustower 102) is attached and supports the upper arm 2 and the like of the front suspension apparatus 1.
A bumper reinforcement 104 (see FIG. 4) extending in the vehicle width direction is connected to the front end portion of the front side frame 100 via a crash can 103.

  The front subframe 101 extends in the front-rear direction below the front side frame 100 and supports the lower arm 3 and the like of the front suspension device 1.

  As shown in FIG. 4, an engine room 110 </ b> A is configured in a space surrounded by the left and right side members 105, 105 (only the left side of the vehicle is illustrated), the front cross member 106, and the lower brace 107 in the front subframe 101. . In this engine chamber 110A, a power train 110 (see FIG. 4) including an engine, a transmission, and an operating mechanism (differential) is disposed. The engine provided in the power train 110 may be either vertically or horizontally placed, and the engine room 110A may be configured as a motor room in which a motor or the like is arranged instead of the engine.

Next, the structures of the upper arm 2 and the lower arm 3 will be described with reference to FIGS. 1 to 3 and FIG.
The upper arm 2 is provided with vehicle body side shaft support portions 21 (21f, 21r) which are supported by the front side frame 100 on the vehicle body side on the front and rear sides.

  As shown in FIGS. 1 to 3, 6, and 7, the lower arm 3 is provided with vehicle body side shaft support portions 31 (31 f and 31 r) that are supported by the front subframe 101 on the vehicle body side on the front and rear sides. Yes. Further, the lower arm 3 includes a front arm portion 33 extending between the front vehicle body front shaft support portion 31f and the knuckle side pivot support portion 32 of the front and rear vehicle body side shaft support portions 31, and a rear vehicle body rear shaft support portion 31r. And a rear arm part 34 extending between the knuckle side pivotal support part 32 and a knuckle side pivotal support part 32. Further, the lower arm 3 has a substantially A shape in a plan view extending in the vehicle width direction while opening forward and backward toward the vehicle body side so that the front arm portion 33 and the rear arm portion 34 are substantially symmetrical with respect to the vehicle width direction. It is arranged horizontally in the shape of.

Specifically, a difference between the front suspension apparatus 1A of the conventional example shown in FIG. 8 and the front suspension apparatus 1 of the present embodiment will be described.
FIG. 8 is an explanatory diagram of a conventional front suspension device 1A, schematically showing the wheel support member 4 omitted. Moreover, the code | symbol 116 in FIG. 8 shows a dash panel.

  A conventional front suspension apparatus 1A shown in FIG. 8 includes an L-shaped lower arm 3A in which a rear arm portion 34A extends further rearward than the rear arm portion 34 of the present embodiment.

  The L-type lower arm 3A receives a load from the front wheel 117, so that a moment load that tends to swing in the left-right direction about the vehicle body front shaft support portion 31Af of the front arm portion 33A acts on the L-type lower arm 3A. The vertical wall portion is set along the edges on the both sides in the width direction of the rear arm portion 34A so as not to bend.

  On the other hand, in the A-type lower arm 3 of this embodiment, one vertical wall portion 37 is set on each of the front and rear arm portions 33 and 34.

  Further, the vehicle body front side shaft support portion 21f of the upper arm 2 and the vehicle body front side shaft support portion 31f of the lower arm 3, and the vehicle body rear side shaft support portion 21r of the upper arm 2 and the vehicle body rear side shaft support portion 31r of the lower arm 3 are substantially in plan view. Upper and lower arms 2 and 3 are arranged so as to overlap (see FIGS. 5 and 6).

Next, the specific structure of the lower arm 3 is shown in FIG. 7A in which the lower arm 3 is divided into a wheel side (wheel support member 4 side) region Zb, a vehicle body side region Za, and an intermediate region Zm in the vehicle width direction. ) And (b).
FIG. 7 is a bottom view (a) and a rear view (b) of the lower arm.

  The rear arm portion 34 extends with a greater inclination toward the rear inward in the vehicle width direction than the front arm portion 33. That is, the rear arm part 34 is inclined and extended rearward toward the inner side in the vehicle width direction so as to be displaced rearward larger than the forward shift amount (offset amount) of the front arm part 33.

  This is because the inner wheel needs to be steered larger than the outer wheel when turning the vehicle, and the support space is secured by ensuring sufficient space between the steered space and the front and rear vehicle body side shaft support portions 31f, 31r. This is to achieve both.

  A damper support member 36 that extends in the front-rear direction and supports the damper 51 of the shock absorber 5 between the front-rear direction of the outer portions in the vehicle width direction of the intermediate regions Zm of the front arm portion 33 and the rear arm portion 34 in the lower arm 3. Is lying horizontally. The damper support member 36 includes a damper shaft support portion 36 a that supports the lower end portion 54 of the damper 51.

  The front arm portion 33, the rear arm portion 34, and the damper support member 36 constitute a truss structure in the wheel side region Zb, and ensure the strength of this portion.

  In the intermediate region Zm, the front arm portion 33 extends linearly forward toward the inner side in the vehicle width direction, whereas the rear arm portion 34 projects forward to prevent interference with the steered front wheel 117. And a bent portion 39m (hereinafter referred to as “intermediate bent portion 39m”) extending in a U-shape (arch shape). That is, as shown in FIG. 7B, the rear arm portion 34 detours forward with respect to an imaginary straight line L10 that linearly connects the vehicle body rear shaft support portion 31r and the knuckle side pivot support portion 32 of the lower arm 3. It extends like so. In other words, the rear arm portion 34 includes a boundary portion between the wheel side region Zb and the intermediate region Zm (a wheel side bent portion 39b described later) and a boundary portion between the intermediate region Zm and the vehicle body side region Za (the vehicle body side described later). It extends so as to detour forward with respect to a virtual straight line L11 that connects the bent portion 39a) in a straight line (see FIG. 7B).

  In the vehicle body side area Za, the rear arm part 34 and the front arm part 33 both extend substantially in the front-rear direction, and at the boundary between the vehicle body side area Za and the intermediate area Zm, the intermediate area Zm of the front arm part 33 A vehicle body side shaft support portion connecting portion 130f that integrally connects the vehicle width direction inner portion and the vehicle body front side shaft support portion 31f is formed, and the vehicle width direction side portion of the intermediate region Zm of the rear arm portion 34, A rear vehicle-body-side shaft support connecting portion 130r that integrally connects the rear-side shaft support portion 31r is configured.

  In addition, the rear arm portion 34 and the front arm portion 33 are each provided with a vertical wall portion 37 extending in the vertical direction and a wall thickness in the vertical direction that is smaller than the vertical wall portion 37 in the front-rear direction with respect to the vertical wall portion 37. A protruding horizontal rib 38 is provided.

  The vertical wall portion 37 has a vertical rib 37a that has a cross section in the extending direction that is thicker in the vertical direction than in the front-rear direction and protrudes on both the upper and lower sides with respect to the horizontal rib 38 (FIG. 7A). (See (b)). The vertical wall portion 37 is not limited to the embodiment having the vertical ribs 37a on the upper and lower sides, and may have a configuration having the vertical ribs 37a on at least one of the upper and lower sides.

Hereinafter, the vertical wall portion 37 and the horizontal rib 38 of the rear arm portion 34 will be described.
In the vertical wall portion 37, in addition to the intermediate bent portion 39m, a bent portion 39b (hereinafter referred to as “wheel side bent portion 39b”) is also formed at a boundary portion between the wheel side region Zb and the intermediate region Zm. In addition, a bent portion 39a (hereinafter referred to as “vehicle body side bent portion 39a”) is also formed at the boundary portion between the intermediate region Zm and the vehicle body side region Za, and a total of three bent portions 39 (39a, 39m, 39b). Of the three bent portions 39, the wheel-side bent portion 39b and the vehicle body-side bent portion 39a are bent rearward in a convex shape.

  The vertical wall portion 37 extends in an S shape in plan view having two bent portions 39 of the vehicle body side bent portion 39a and the intermediate bent portion 39m in the intermediate region Zm and the vehicle body side region Za (FIG. 7). (See (b)).

  The horizontal rib 38 includes a rear horizontal rib 38r extending so as to approach the vertical wall portion 37 forward from the rear portion of the vehicle body rear shaft support portion 31r, and a front portion of the vehicle body rear side shaft support portion 31r from at least the front portion of the intermediate bent portion 39m. And a front horizontal rib 38f extending so as to approach the vertical wall portion 37.

  The rear horizontal rib 38r protrudes rearward from an intermediate position in the vertical direction of the rear portion of the vertical wall portion 37 so as to be integrally joined to the rear portion of the vehicle body rear side pivot support portion 31r and the inner edge in the vehicle width direction. Extends from the wheel side region Zb through the rear portion of the vehicle body side bent portion 39a to the intermediate region Zm and extends outward in the vehicle width direction, and the protruding length is gradually shortened so as to approach the vertical wall portion 37 gradually. It is formed as follows.

  The front horizontal rib 38f horizontally protrudes forward from an intermediate position in the vertical direction of the front portion of the vertical wall portion 37, and passes through the front portion of the intermediate bent portion 39m from the joint portion with the damper support member 36 of the vertical wall portion 37. Thus, it extends to reach the boundary between the intermediate area Zm and the vehicle body side area Za, and is formed so that the protruding length becomes shorter so as to gradually approach the vertical wall section 37.

  The rear arm portion 34 forms a rear edge 34r of the rear arm portion 34 by a portion where the rear horizontal rib 38r is not formed and the rear horizontal rib 38r, and the vertical wall portion 37. The front edge 34f of the rear arm portion 34 is formed by the portion where the front horizontal rib 38f is not formed and the front horizontal rib 38f.

The vertical wall portion 37 described above extends continuously in the rear arm portion 34 so as to connect the vehicle body rear shaft support portion 31r and the knuckle side pivot support portion 22, but the front edge of the rear arm portion 34 is provided. The straight line extends so as to be closer to the vehicle width direction reference line (Lw) (see FIG. 7) than the ridge lines of 34f and the rear edge 34r.
Here, the vehicle width direction reference line Lw indicates a virtual straight line parallel to the vehicle width direction not including the vertical component and the front-rear component, as shown in FIGS.

  In other words, the vertical wall portion 37 is located in front of the front and rear width of the rear arm portion 34 in the vehicle body side region Za so as to connect the vehicle body rear side shaft support portion 31r and the knuckle side pivot support portion 22 with the shortest path (front side). The intermediate region Zm extends to the rear side of the rear arm portion 34 (to the rear edge 34r).

  Moreover, since the lower arm 3 forms the truss structure in a plan view as described above in the wheel side region Zb, it is possible to ensure sufficient strength. In such a high-strength wheel side region Zb, the vertical wall portion 37 of the rear arm portion 34 is displaced in the vehicle width direction so as to be displaced rearward larger than the forward displacement amount of the front arm portion 33 as described above. The inner part is inclined to the rear and extends. With this configuration, a longitudinal component in the wheel side region Zb of the vertical wall portion 37 can be secured, and accordingly, a longitudinal component in the intermediate region Zm of the vertical wall portion 37 and the vehicle body side region Za is shortened. can do.

  Therefore, the vertical wall portion 37 has sufficient truss structure for the wheel side region Zb having a large longitudinal component, while the S-shaped vertical wall portion 37 is formed in the intermediate region Zm and the vehicle body side region Za. More straight lines can be made so as to approach the vehicle width direction reference line.

The lower arm 3 includes two reinforcing members 30 a and 30 b that connect the rear arm portion 34 and the front arm portion 33.
Of these two reinforcing members 30a and 30b, the vehicle body side reinforcing member 30a on the vehicle body side includes the boundary portions between the intermediate region Zm of the front arm portion 33 and the rear arm portion 34 and the vehicle body side region Za, That is, it extends in the front-rear direction so as to connect the front and rear vehicle body side shaft support part connecting portions 130f, 130r. On the other hand, the wheel side reinforcing member 30b on the wheel side is formed by joining the intermediate bent portion 39m of the rear arm portion 34 and the front vehicle body side pivot support connecting portion 130f (in other words, the front arm portion 33 and the vehicle body side reinforcing member 30a). The front part of the vehicle is inclined to the front inner side in the vehicle width direction so as to connect to the corner part.

  That is, the vertical wall portion 37 of the rear arm portion 34 is connected to the front arm portion 33 at the vehicle body side bent portion 39a and the vehicle body side reinforcing member 30a via the front horizontal rib 38f, and at the intermediate bent portion 39m. Is connected to the front arm portion 33 by a wheel side reinforcing member 30b via a front horizontal rib 38f.

Next, the attachment of the lower arm 3 to the vehicle body will be described with reference to FIGS.
On the outer side wall surface 101a of the front subframe 101 in the vehicle width direction, mounting recesses 101b (101bf, 101br) that are open to the vehicle width direction outer side and the lower side so that the lower arm 3 can be attached are provided to be separated on the front and rear sides. It has been. A mounting bracket 112 having a U-shape in plan view that opens outward in the vehicle width direction is fixed to the side walls inside these mounting recesses 101b by fastening bolts B2 and nuts N2 or by welding (FIG. 2, (See FIG. 6).

  These front and rear mounting brackets 112 and 112 are fixed so that their respective axis lines L2 (axis lines L2 of the shaft support portion of the rotating shaft) extend coaxially and parallel to the vehicle front-rear direction reference line Ly.

  The elastic bushes 35f and 35r provided on the vehicle body side shaft support portion 31 on each of the front and rear sides of the lower arm 3 are connected to the front sub via bolts B2 and nuts N2 as rotation shafts extending in the front-rear direction on the center axis (L2). It is pivotally supported by a mounting bracket 112 provided in the mounting recess 101 b of the frame 101.

  Accordingly, the vehicle body front side shaft support portion 31f and the vehicle body rear side shaft support portion 31r have elastic bushes 35f and 35r each having an axis L2 parallel to the vehicle front-rear direction reference line Ly extending in the front-rear direction. The elastic bushes 35f and 35r on the side are coaxial (see FIGS. 2 and 6). That is, the lower arm 3 is pivotally supported on the front subframe 101 in a horizontal posture (see FIGS. 2 and 6).

  The wheel support member 4 described above supports the front wheel 117, the disc brake and the like so as to be rotatable. The wheel support member 4 includes a knuckle side which is provided at the outer end in the vehicle width direction of each of the upper and lower arms 2 and 3. The pivot parts 22 and 32 are attached (refer FIG. 2, FIG. 3).

  Specifically, as shown in FIGS. 2, 3, and 6, the wheel support member 4 includes an upper extension 41 that extends upward at an intermediate position in the front-rear direction, and the upper arm 2 is connected to the upper end 41 a of the upper extension 41. The lower arm 3 is attached to the lower end portion 42a of the wheel support member 4 via a ball joint. Furthermore, as shown in FIG. 5, the wheel support member 4 includes a front extension 43 (a knuckle arm) for connecting the tie rod 6 while extending forward at an intermediate position in the vertical direction.

  As shown in FIGS. 1 to 3 and FIG. 5, the shock absorber 5 described above includes a damper 51 and a coil spring 52, and the coil spring 52 is disposed on the upper outer side of the damper 51 so that the center axes L <b> 6 are coaxial. Provided, and extends in the vertical direction so that the central axis L6 is orthogonal to the axis L2 of the lower arm 3 in a side view (see FIG. 2). The damper 51 provided between the vehicle body and the lower arm 3 has a lower end portion 54 of the damper 51 connected to the lower arm 3 and an upper end portion 53 of the damper 51 supported on the vehicle body side.

  The lower end portion 54 (lower arm side shaft support portion) of the shock absorber 5 is fitted with an elastic bush 54a so that its axis L4 extends in the front-rear direction (see FIGS. 1 and 2).

  The elastic bush 54a provided at the lower end portion 54 of the shock absorber 5 is provided with the above-described damper shaft support portion 36a of the lower arm 3 via a bolt B4 and a nut N4 as a rotation shaft (L4) extending in the front-rear direction (FIG. 7 ( a) and (b)).

The lower arm 3 provided in the above-described front suspension device 1 of the present embodiment is provided with vehicle body side shaft support portions 31 (31f, 31r) that are supported on the vehicle body side on the front and rear sides, and the vehicle body side shaft support portions on the front and rear sides. 31, a front arm portion 33 extending between the vehicle body front shaft support portion 31 f and the knuckle side pivot support portion 32 pivotally supported by the wheel support member 4, and a vehicle body rear side shaft support portion 31 r and a knuckle side pivot support portion 32. A lower arm 3 (see FIGS. 1 to 3, 5, and 6), and the lower arm 3 is arranged so that the front arm portion 33 and the rear arm portion 34 are moved forward and backward in the vehicle body side. As shown in FIG. 6 and FIG. 7 (b), the front and rear vehicle body side shaft support portions 31f and 31r are both coaxial in the longitudinal direction of the vehicle. (See FIG. 6), the front arm 33 and The rear arm portion 34 as an arm portion on one side of the side arm portion 34 is connected to a virtual straight line L10 (see FIG. 7B) that linearly connects the knuckle side pivotal support portion 32 and the vehicle body rear side shaft support portion 31r. extends bypassing the V-shape as viewed from the convex forward against the the one side of front-side arm portion 3 3 as the arm portion of the other side, the knuckle-side pivot portion 32 and the vehicle body front The side shaft support portion 31 f is configured to be connected in a substantially linear shape, and the rear arm portion 34 has a vertical wall portion 37 extending in the vertical direction and a vertical thickness smaller than the vertical wall portion 37. Horizontal ribs 38 projecting in the direction (see FIGS. 6, 7A and 7B), and the vertical wall portion 37 is connected to the front edge 34f (front ridge line 34f) and the rear edge of the rear arm portion 34. A straight line extending so as to be closer to the vehicle width direction reference line Lw than 34r (rear ridge line 34r) (See the figure).

  According to the above configuration, it is possible to make the vertical wall portion 37 lighter and more rigid than the case where the vertical wall portion 37 is provided on the rear edge 34 r of the rear arm portion 34.

  More specifically, the rear arm portion 34 extends from the wheel side to the vehicle body side while bending to the rear side, and is curved or bent to prevent interference with the front wheel 117 to be steered. It extends as a letter. In such a rear arm portion 34, stress tends to concentrate on the load in the vehicle width direction, and it is difficult to increase the rigidity.

  However, the rear arm portion 34 of the present embodiment is provided with a horizontal rib 38 and a vertical wall portion 37, and the vertical wall portion 37 is further arranged in the vehicle width direction than the front edge 34 f and the rear edge 34 r of the rear arm portion 34. By extending in a straight line so as to approach the reference line Lw, it is possible to reduce the weight while increasing the rigidity in the vehicle width direction.

  Specifically, in the case where the rear arm portion 34 is reinforced by the vertical ribs 37a, the illustration is omitted if it is conventional, but from the viewpoint of the section modulus, the front edge 34f (the inner edge in the width direction) of the rear arm portion 34 or In general, vertical ribs 37a are provided along the rear edge 34r (outer edge in the width direction).

  On the other hand, in the present embodiment, as described above, the vertical wall portion 37 provided with the vertical rib 37a (that is, the vertical wall portion 37 thick in the vertical direction) is used as the front edge 34f ( A vertical wall portion that is thicker in the vertical direction as in the prior art by linearly extending so as to be closer to the vehicle width direction reference line Lw than the front edge line 34f) and the rear edge 34r (rear edge line 34r) The load is efficiently transmitted from the wheel support member 4 side to the vehicle body side along the vertical wall portion 37 having a short distance in the front-rear direction compared to a structure in which 37 is formed along the rear edge 34r of the rear arm portion 34. Therefore, high rigidity in the vehicle width direction can be achieved.

  In addition, it is possible to reduce the number and cross-sectional area of the reinforcing members 30a and 30b that reinforce the bent or curved portion where the stress of the rear arm portion 34 tends to concentrate. Specifically, as shown in FIG. 7B, since the wheel side reinforcing member 30b that reinforces the intermediate bent portion 39m can be made one, the weight of the lower arm 3 can be reduced.

  By the way, since the rotation radii of the inner ring and the outer ring are different, it is necessary to cut the rear side of the inner ring larger than the outer ring. Generally, the rear arm portion requires more clearance with the wheel.

  For this reason, the above-described configuration in which the vertical wall portion 37 and the horizontal rib 38 are provided and the vertical wall portion 37 is linearly extended so as to approach the vehicle width direction reference line Lw is used as a wheel cut on the inner ring side during steering. By applying to the rear arm portion 34 having a large value, both the steering angle and the suspension support rigidity can be achieved.

  As an aspect of the present invention, an intermediate bent portion 39m that protrudes forward is formed in the vertical wall portion 37, and the horizontal rib 38 serves as an edge on one side from the rear portion of the vehicle body rear shaft support portion 31r toward the front. A rear horizontal rib 38r extending so that the rear edge 38ra approaches the vertical wall portion 37, and a front edge 38fa as an edge on the other side from the front portion of the intermediate bent portion 39m toward the front portion of the vehicle body rear shaft support portion 31r Is formed of a front horizontal rib 38f extending so as to approach the vertical wall portion 37 (see FIG. 7B).

  According to the above configuration, the rear arm portion 34 having the vertical wall portion 37 can be effectively reinforced by the horizontal rib 38 while ensuring a gap with the front wheel 117 to be steered.

  More specifically, the rear arm portion 34 provided in the lower arm 3 extends in the rearward direction from the wheel side toward the vehicle body side, and is formed in a letter-like shape that is projected forward in a plan view to prevent interference with the front wheel. Such a rear arm portion 34 is preferably formed in a straight line along the vehicle width direction reference line Lw as much as possible in order to ensure the load transferability. However, the more the rear arm portion 34 is linear, the more conspicuous the bent portion is at the end of the linear portion. That is, the greater the degree of bending of the intermediate bent portion 39m, the more easily stress with respect to the load is concentrated on the intermediate bent portion 39m as compared with the linear portion.

  Therefore, as in the present embodiment, as the horizontal rib 38, a rear horizontal rib 38r extending so as to approach the vertical wall portion 37 forward from the rear portion of the rear vehicle body side shaft support portion 31, and an intermediate bent portion 39m. The front side horizontal rib 38f extending from the front part toward the front part of the vehicle body side shaft support part 31 on the rear side so as to approach the vertical wall part 37, thereby providing the vehicle body side bent part 39a of the vertical wall part 37. The rear horizontal rib 38r reinforces the rear side (the side from which the vehicle body side bent part 39a protrudes) and the intermediate bent part 39m of the vertical wall part 37 from the front side (the side from which the intermediate bent part 39m protrudes) to the front horizontal rib. Since it is reinforced by 38f (see FIG. 7B), the vertical wall portion 37 of the rear arm portion 34 can be efficiently reinforced by the horizontal rib 38 while ensuring a gap with the front wheel 117 to be steered. Moreover, the rear arm portion 34 does not increase in weight compared to the case where the entire outer edge and inner edge of the vertical wall portion 37 are reinforced by the horizontal rib 38.

  As an aspect of the present invention, the vertical wall portion 37 is substantially S-shaped in plan view having an intermediate bent portion 39m and a vehicle body side bent portion 39a as at least two bent portions, and the intermediate bent portion 39m and the front arm portion 33. The front-side vehicle-body-side shaft support connecting portion 130f is connected by the wheel-side reinforcing member 30b via the front-side horizontal rib 38f, and the vehicle-body-side bent portion 39a and the front-side vehicle-body-side shaft support connecting portion 130f Are connected by a vehicle body side reinforcing member 30a through a front horizontal rib 38f (see FIG. 7B).

  As described above, the vertical wall portion 37 is formed by the reinforcing members 30a and 30b via the vehicle body side shaft support connecting portion 130f and the front horizontal rib 38f on the front side of the front arm portion 33 in each of the two bent portions 39m and 39a. By connecting, for example, the front horizontal rib 38f can be provided at the peripheral edge portion of the connecting portion between the reinforcing members 30a, 30b and the vertical wall portion 37, so that the reinforcing members 30a, 30b and the vertical wall portion 37 are directly connected. Compared with the case where it is connected, stress can be prevented from concentrating around the connecting portion and the rigidity can be increased. As a result, the number of reinforcing members 30a and 30b can be reduced or the thickness can be reduced. Further, it is possible to further increase the weight and rigidity, and as a result, the vertical wall portion 37 can be straightened and reinforced efficiently.

  As an aspect of the present invention, the vehicle body side shaft support portions 31f and 31r on the front and rear sides of the lower arm 3 have elastic bushes 35f and 35r each having an axis L2 parallel to the vehicle front-rear direction reference line Ly. The elastic bushes 35f and 35r are coaxial (see FIGS. 6 and 7B).

  According to the above configuration, the load in the front-rear direction is received by the coaxial vehicle-body-side shaft support portions 31f, 31r on both front and rear sides while firmly receiving the load in the vehicle width direction by the front-rear vehicle-side shaft support portions 31f, 31r. Can do. That is, the geometry does not change as the lower arm 3 tilts.

In the correspondence between the configuration of the present invention and the above-described embodiment, the knuckle member of the present invention corresponds to the wheel support member 4 of the present embodiment.
The vehicle body side shaft support portion on the front side corresponds to the vehicle body front side shaft support portion 31f,
The rear vehicle body side shaft support portion corresponds to the vehicle body rear side shaft support portion 31r,
The bent portion protruding to the other side according to claim 3 corresponds to the intermediate bent portion 39m protruding forward in the present embodiment,
The horizontal rib extending from the one side portion of the vehicle body side shaft support portion on the one side to the other side corresponds to the rear horizontal rib 38r extending forward from the rear portion of the vehicle body rear shaft support portion 31r,
The horizontal rib extending from the other side portion of the bent portion toward the other side portion of the vehicle body side shaft support portion on the one side is formed from the front portion of the intermediate bend portion 39m to the front portion of the vehicle body rear side shaft support portion 31r. Corresponding to the front horizontal rib 38f extending toward
The two bent portions according to claim 4 correspond to the intermediate bent portion 39m and the vehicle body side bent portion 39a of the present embodiment,
The horizontal rib according to claim 4 corresponds to the front horizontal rib 38f, but the present invention is not limited to the configuration of the above-described embodiment.

  As described above, the present invention relates to a front lower arm structure of an automobile, and is particularly useful for a structure of a lower arm provided in a double wishbone type front suspension device.

1. Front suspension device (front suspension structure)
3 ... Lower arm 4 ... Wheel support member (knuckle member)
31 ... Vehicle body side shaft support portion 31f ... Vehicle body front side shaft support portion (front vehicle body side shaft support portion)
31r: Car body rear shaft support (rear car body side shaft support)
34f ... rear edge 34r ... rear arm rear edges 30a, 30b ... reinforcing member 32 ... knuckle side pivot 33 ... front arm 34 ... rear arm 35f, 35r ... front and rear elastic bushes 37 ... vertical wall 38 ... horizontal rib 38f ... front horizontal rib 38r ... rear horizontal rib 39m ... intermediate bent part (bent part)
39a ... Bending part (bending part) on the vehicle body
130f: Front-side vehicle-body-side shaft support coupling portion L2 ... Shaft (axis of the vehicle-body-side shaft support, axis extending in the front-rear direction of the vehicle-body-side shaft support)
Lw: vehicle width direction reference line Ly: vehicle longitudinal direction reference line L10: virtual straight line connecting the knuckle side pivotal support portion and the vehicle body rear side pivot support portion in a straight line

Claims (5)

A vehicle body side shaft support portion that pivots to the vehicle body side is provided on each of the front and rear sides, and between the vehicle body side shaft support portions on the front and rear sides, between the front vehicle body side shaft support portion and the knuckle side pivot support portion that pivots on the knuckle member. A front lower arm structure for an automobile comprising: a front arm portion extending; and a rear arm portion extending between a rear vehicle body side shaft support portion and a knuckle side pivot support portion;
The lower arm is substantially A-shaped in plan view extending in the vehicle width direction so that the front arm portion and the rear arm portion open forward and backward on the vehicle body side,
The shaft centers of the vehicle body side shaft support portions on the front side and the rear side both extend in the vehicle front-rear direction,
The arm portion on one side of the front arm portion and the rear arm portion has the one side with respect to an imaginary straight line that linearly connects the knuckle side pivot support portion and the vehicle body side shaft support portion on the one side. Extends around the other side in a convex U-shape or curved,
The arm portion of the other side, is said knuckle side pivot portion, a shape which connects the vehicle body-side bearing portions of the other side substantially linearly,
The arm portion on the one side is provided with a vertical wall portion extending in the vertical direction, and a horizontal rib protruding in the front-rear direction with a thickness lower than the vertical wall portion in the vertical direction,
A front lower arm structure of an automobile in which the vertical wall portion is straightened and extended so as to be closer to a reference line in the vehicle width direction than each ridgeline of a front edge and a rear edge of the arm portion on the one side. The front lower arm structure for an automobile according to claim 1, wherein the one arm portion is the rear arm portion, and the one side is the rear side. The vertical wall portion of the arm portion on the one side is formed with a bent portion convex to the other side,
The horizontal rib extends so that an edge on one side of the horizontal rib approaches the vertical wall portion from a portion on one side of the vehicle body side shaft support portion on the one side toward the other side, and the bent The edge of the other side of the horizontal rib extends from the part on the other side of the part toward the part on the other side of the vehicle body side pivot support part on the one side so as to approach the vertical wall part. Item 3. A front lower arm structure for an automobile according to Item 1 or 2. The vertical wall portion is substantially S-shaped in plan view having at least two bent portions,
4. The vehicle body side shaft support connecting portion of the other arm portion at each of the two bent portions is connected by a reinforcing member via the horizontal rib. The vehicle front lower arm structure described. The front and rear vehicle body side shaft support portions each include an elastic bush having an axis parallel to a vehicle front-rear direction reference line extending in the front-rear direction, and the elastic bushes on each of the front and rear sides are coaxial. 5. A front lower arm structure for an automobile according to any one of 1 to 4.

Images