Front suspension system
The suspension arm design with an easily breakable damper support portion separates the front wheel from the vehicle body during small overlap collisions, effectively reducing vehicle deformation by concentrating load on the damper support and applying a lateral force to move the wheel and body apart.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MAZDA MOTOR CORP
- Filing Date
- 2022-09-20
- Publication Date
- 2026-05-15
AI Technical Summary
Existing suspension arm configurations in vehicles fail to adequately suppress vehicle body deformation and load transmission during small overlap collisions, as they rely on outward rotation of the front wheels, leading to significant deformation of the side sill and passenger compartment.
A front suspension device with a suspension arm having a damper support portion that includes an easily breakable section, allowing the arm to deform and fracture at this point, thereby separating the front wheel from the vehicle body, reducing deformation by concentrating load on the damper support and applying a lateral force to move the wheel and body apart.
The suspension arm design effectively suppresses vehicle body deformation by allowing the front wheel to separate from the body, reducing load transmission and enhancing the vehicle's stability during small overlap collisions.
Smart Images
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Abstract
Description
Technical Field
[0001] The technology disclosed herein belongs to the technical field related to a front suspension device.
Background Art
[0002] Conventionally, as one form of a frontal collision of a vehicle, a small overlap collision in which the vehicle collides with an obstacle outside the vehicle width direction from the front side frame of the vehicle is known. At the time of this small overlap collision, the front wheel may move backward and collide with a vehicle body member located on the rear side of the vehicle of the front wheel. In this case, there is a possibility that a collision load acts on the passenger compartment due to the collision at that time.
[0003] As a countermeasure against such a small overlap collision, for example, in Patent Document 1, a vulnerable portion is provided in the vicinity of the vehicle body mounting portion of the suspension arm, and when a load of a predetermined value or more is input from the front side of the vehicle to the front wheel, the front wheel is centered on the vulnerable portion. The suspension arm is bent so as to rotate toward the rear side of the vehicle.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In the configuration of Patent Document 1, by bending the suspension arm based on the vulnerable portion, the front wheel can be rotated outward in the vehicle width direction around the vulnerable portion. As a result, it can be expected to reduce the collision load acting on the passenger compartment via the front wheel as much as possible.
[0006] However, the inventors of this application have found that, with the configuration described in Patent Document 1, the front wheels rotate outward in the vehicle width direction as a small overlap collision progresses, while the side sill located at the rear of the vehicle deforms relatively significantly. Therefore, there is room for improvement from the standpoint of suppressing deformation of the vehicle body and reducing load transmission to the passenger compartment.
[0007] The technology disclosed herein has been developed in view of these points, and its purpose is to suppress vehicle body deformation as much as possible during small overlap collisions. [Means for solving the problem]
[0008] To solve the aforementioned problems, a first aspect of the technology disclosed herein provides a front suspension device comprising: a suspension arm having a front wheel support portion at one end for supporting the front wheel of the vehicle, and a body mounting portion at the other end that is attached to a vehicle body member of the vehicle so as to be located inward in the vehicle width direction from the front wheel support portion; and a damper supported by a damper support portion provided near the front wheel support portion of the suspension arm and connected to the vehicle body at its upper end, wherein the damper support portion has a portion that is easily broken.
[0009] In this configuration, during a small overlap collision, a rearward load is applied to the front wheels, resulting in a rearward load being applied to the front wheel support portion of the suspension arm. Since the inner end of the suspension arm in the vehicle width direction is connected to the vehicle body by the vehicle body mounting portion, when a rearward load is applied to the front wheel support portion, the suspension arm deforms in a curved manner so that the outer portion in the vehicle width direction is positioned further rearward. At this time, since the damper is connected to the vehicle body, the damper support portion that supports the damper is less likely to be displaced in the vicinity of the front wheel support portion of the suspension arm. On the other hand, the portion of the suspension arm that is outside the damper support portion in the vehicle width direction is displaced more significantly than the damper support portion. As a result, the collision load is concentrated on the damper support portion, and the suspension arm breaks at the location of the easily breakable portion of the damper support portion. As a result, the front wheels become able to move independently from the vehicle body.
[0010] On the other hand, the bending deformation of the suspension arm causes a reaction force with a lateral component to be applied from the suspension arm to the vehicle body. In particular, if a load is applied to the suspension arm even after it has broken, a lateral force will be applied to the vehicle body that will move it away from the front wheel. As a result, the vehicle body will move laterally (so-called glans off), and the front wheel and the vehicle body will move away from each other.
[0011] As a result, deformation of the vehicle body components by the front wheels is suppressed, thus reducing deformation of the vehicle body during small overlap collisions.
[0012] A second aspect of the technology disclosed herein is configured such that, in the first aspect, the damper support portion has a hole that accommodates the lower end of the damper and penetrates in the longitudinal direction of the vehicle, and the easily breakable portion is provided in the portion of the damper support portion other than the hole.
[0013] With this configuration, the portion of the suspension arm with the easily fractured section is relatively thinner compared to the rest of the suspension arm. As a result, in the event of a small overlap collision, the suspension arm is more likely to fracture starting from the easily fractured section, thus more effectively suppressing the deformation of the vehicle body during a small overlap collision.
[0014] A third aspect of the technology disclosed herein is a configuration in which, in the second aspect, the easily breakable portion is provided in both the portion above and the portion below the hole in the damper support portion.
[0015] With this configuration, during a small overlap collision, the suspension arm is more likely to break at the point of easy fracture. This allows for more effective suppression of vehicle body deformation during a small overlap collision.
[0016] A fourth aspect of the technology disclosed herein is a configuration in which, in the first aspect, the easily breakable portion is a groove that is recessed in the longitudinal direction of the vehicle.
[0017] In other words, since the collision load during a small overlap collision is a load directed from the front of the vehicle to the rear of the vehicle, with the above configuration, the suspension arm is more likely to break at the point of easy fracture during a small overlap collision. This makes it possible to more effectively suppress the deformation of the vehicle body during a small overlap collision.
[0018] A fifth aspect of the technology disclosed herein is a configuration in which, in the first aspect, the rear surface of the outer portion of the suspension arm, which is the portion from the damper support to the front wheel support, is curved in an arch shape toward the front of the vehicle when viewed in plan.
[0019] According to this configuration, due to the collision load in a small overlap collision, the outer portion is likely to deform such that the front surface portion folds like a mountain. Therefore, if a breakable portion is provided in the damper support portion, the suspension arm is likely to break at the breakable portion as a base point. Thereby, the deformation of the vehicle body during a small overlap collision can be more effectively suppressed.
[0020] A sixth aspect of the technology disclosed herein is configured such that, in the fifth aspect, the breakable portion is a groove portion formed on the front surface portion of the damper support portion and recessed in the vehicle longitudinal direction.
[0021] According to this configuration, when the front surface portion deforms to fold like a mountain, the breakable portion is particularly likely to become the base point of breakage. Thereby, the deformation of the vehicle body during a small overlap collision can be more effectively suppressed.
[0022] A seventh aspect of the technology disclosed herein is configured such that, in the sixth aspect, the position of the breakable portion in the vehicle width direction is the same as the position of the curved top portion located most on the vehicle front side in the rear surface portion in the vehicle width direction.
[0023] According to this configuration, since the front surface portion is particularly likely to deform by folding at the position of the breakable portion, the breakable portion is likely to become the base point of breakage. Thereby, the deformation of the vehicle body during a small overlap collision can be more effectively suppressed.
[0024] An eighth aspect of the technology disclosed herein is configured such that, in any one of the first to seventh aspects, the suspension arm is formed by forging.
[0025] According to this configuration, the rigidity of the entire suspension arm can be increased, so that the support performance of the suspension arm under normal conditions can be sufficiently enhanced. Further, if the rigidity of the entire suspension arm is high, it becomes easier for a portion with reduced rigidity compared to the surroundings, such as an easily broken portion, to be the basis for breakage. Also, since the remaining portion after the suspension arm breaks is less likely to buckle, the lateral force due to the compressive deformation of the remaining portion can be effectively exerted, and the deformation of the vehicle body during a small overlap collision can be more effectively suppressed.
Effect of the Invention
[0026] As described above, according to the technology disclosed herein, the deformation of the vehicle body during a small overlap collision can be suppressed as much as possible.
Brief Description of the Drawings
[0027] [Figure 1] FIG. 1 is a plan view showing a main part of the front portion of a vehicle equipped with a suspension device according to an exemplary embodiment. [Figure 2] FIG. 2 is a perspective view of the main part of the front portion of the vehicle as viewed from the front side and the upper side. [Figure 3] FIG. 3 is an enlarged view showing the periphery of the right suspension device in the front portion of the vehicle. [Figure 4] FIG. 4 is a perspective view of the right suspension arm as viewed obliquely from above. [Figure 5] FIG. 5 is a plan view showing the right suspension arm. [Figure 6] FIG. 6 is a front view showing the right suspension arm. [Figure 7] FIG. 7 is an enlarged view showing an enlarged outer portion of the right suspension arm. [Figure 8] FIG. 8 is a perspective view showing the rear portion of the first insertion portion. [Figure 9] FIG. 9 is a perspective view showing the front portion of the first fastening portion. [Figure 10]Figure 10 is a cross-sectional view taken along the plane corresponding to line XX in Figure 6. [Figure 11] Figure 11 is a schematic plan view showing the state of the right suspension arm before deformation when a collision load is applied to the right front wheel during a small overlap collision with an obstacle on the right front portion of the vehicle. [Figure 12] Figure 12 is a schematic plan view showing the deformation of the right suspension arm when the obstacle moves further back relative to the vehicle from Figure 11, and shows the state of the right suspension arm before it breaks. [Figure 13] Figure 13 is a plan view showing the state in which the obstacle has moved further back relative to the vehicle from Figure 12, resulting in the fracture of the right suspension arm. [Figure 14] Figure 14 is a plan view showing the state in which the obstacle has moved further back relative to the vehicle compared to Figure 13, and the right front wheel has moved to the right rear side of the vehicle. [Modes for carrying out the invention]
[0028] The following describes exemplary embodiments in detail with reference to the drawings.
[0029] (Vehicle front structure) Figures 1 and 2 show the main front part of a vehicle 1 equipped with the suspension device 30 according to this embodiment. The front of the vehicle 1 is provided with a powertrain room 2, which houses a powertrain (not shown) that drives the left and right front wheels 3 of the vehicle 1. The powertrain consists of a power source such as an engine or motor, and a transmission to which the power generated by the power source is input. The powertrain room 2 is formed between a pair of left and right front side frames 11. Hereinafter, the front, rear, top, and bottom of the vehicle 1 may simply be referred to as front, rear, top, and bottom. Also, the left and right sides when viewed from the rear to the front may be referred to as left and right, respectively. The left-right direction coincides with the vehicle width direction.
[0030] Each front side frame 11 extends in the front-to-rear direction. Behind each front side frame 11, a pair of left and right floor frames 12 are positioned, each extending in the front-to-rear direction. On the outer side of each floor frame 12 in the vehicle width direction, a pair of left and right side sills 13 are positioned, each extending in the front-to-rear direction. The left floor frame 12 and the left side sill 13 are connected in the left direction by a left torque box 14, and the right floor frame 12 and the right side sill 13 are connected in the left direction by a right torque box 14. Each side sill 13 is located behind each front wheel 3.
[0031] Below each front side frame 11, a pair of lower frames 20 are positioned on the left and right sides. Each lower frame 20 extends in the front-rear direction and is curved such that its center in the front-rear direction is located inward in the vehicle width direction compared to its front and rear ends. Although not shown in the illustration, each lower frame 20 is connected vertically to each front side frame 11 on the left side and on the right side.
[0032] Each lower frame 20 is provided with a crash can 15 at its front end, and the front end surfaces of these left and right crash cans 15 are fixed to a bumper beam 16 that extends in the left-right direction.
[0033] The front end of each lower frame 20 is connected in the left-right direction by a front cross member 21 that extends in the left-right direction. The rear end of each lower frame 20 is connected in the left-right direction by a rear cross member 23 that extends in the left-right direction. The central part of each lower frame 20 in the front-rear direction is connected in the left-right direction by a central cross member 22 that extends in the left-right direction. The front cross member 21, the rear cross member 23, and the central cross member 22 are each located on the inside of each lower frame 20 in the vehicle width direction.
[0034] As shown in Figure 2, each lower frame 20 is provided with a pair of left and right suspension devices 30 on its outer side in the vehicle width direction. Each suspension device 30 is positioned between the central cross member 22 and the rear cross member 23 in the longitudinal direction. The left and right front wheels 3 are connected to the outer ends of each suspension device 30 in the vehicle width direction (front wheel support section 41, described later) via hub carriers (knuckles). Each suspension device 30 is connected in the lateral direction by an anti-roll bar 31 that extends in the lateral direction.
[0035] Each suspension device 30 has a pair of left and right dampers 32. Each damper 32 extends upward and inward in the vehicle width direction. Specifically, the left damper 32 extends upward and inward in the vehicle width direction, and the right damper 32 extends upward and inward inward in the vehicle width direction. A coil spring is provided at the top of each damper 32. The upper end of each damper 32 is connected to a pair of left and right suspension towers (not shown). Since each of the suspension towers constitutes the vehicle body, each damper 32 is connected to the vehicle body at its upper end.
[0036] (Suspension system) Next, the configuration of the suspension system 30 will be described in detail. Since the left suspension system 30 and the right suspension system 30 are symmetrical, the following explanation will only describe the configuration of the right suspension system 30 in detail, and the configuration of the left suspension system 30 will be omitted.
[0037] The suspension device 30 according to this embodiment is a so-called double wishbone type suspension device. As shown in Figures 3 to 5, the suspension device 30 has suspension arms 33 (lower arms) that extend in the longitudinal and lateral directions. The suspension arm 33 has a front arm 40 that extends substantially straight in the lateral direction and is located relatively to the front, and a rear arm 50 that is located behind the front arm 40 and extends in a curved direction toward the rear towards the left. Both the front arm 40 and the rear arm 50 are formed by forging. In the following description, when the front arm 40 and the rear arm 50 are not specifically distinguished, they may simply be referred to as the suspension arm 33. In addition, although not shown in the figures, an upper arm is also provided separately from the suspension arm 33.
[0038] The front arm 40 has a front wheel support portion 41 at its right end that supports the right front wheel 3. The front wheel support portion 41 has a bracket 41a. The bracket 41a is attached and fixed to the right end of the front arm 40 by bolts and nuts 41b (see Figure 6). The bracket 41a has a pair of bosses 41c that are spaced apart in the front-rear direction. The hub carrier is attached to the upper side of the front wheel support portion 41. Bolts are inserted into each boss 41c from above, and these bolts are fastened with nuts from below to fix the hub carrier to the front wheel support portion 41.
[0039] As shown in Figure 3, the front arm 40 has a first vehicle body mounting portion 42 at its left end, which is attached to the central part of the lower frame 20. In other words, the first vehicle body mounting portion 42 is attached to the vehicle body member (in this case, the right lower frame 20) of the vehicle 1 so as to be located inward in the vehicle width direction from the front wheel support portion 41. The first vehicle body mounting portion 42 has a first bracket 42a, a first cylindrical member 42b (see Figures 4 and 6), and a first support shaft 42c (see Figures 4 and 6). The first cylindrical member 42b has an inner cylinder through which the first support shaft 42c is inserted, a rubber bush arranged around the inner cylinder, and an outer cylinder located outside the rubber bush. The first bracket 42a is attached and supported by the first support shaft 42c. With the first bracket 42a fixed to the vehicle body member (in this case, the lower frame 20), the front arm 40 is rotatable around the first support shaft 42c relative to the vehicle body. In particular, since the first support shaft 42c is positioned to extend in the front-rear direction, the front arm 40 is rotatable in the vertical direction.
[0040] As shown in Figures 4 to 6, the front arm 40 has a damper support portion 44 that supports the damper 32 near the front wheel support portion 41. More specifically, the damper support portion 44 is provided on the outer portion 43 located to the right (outer in the vehicle width direction) of the right end of the rear arm 50. The damper support portion 44 is formed near the left end of the outer portion 43. For this reason, the portion of the front arm 40 from the damper support portion 44 to the front wheel support portion 41 can also be called the outer portion 43. The outer portion 43 extends straight in the left-right direction (vehicle width direction).
[0041] The damper support portion 44 has a hole 44a that penetrates in the front-rear direction. The hole 44a accommodates the lower end of the damper 32. The upper part of the damper support portion 44 above the hole 44a (hereinafter referred to as the upper support portion 44b) and the lower part below the hole 44a (hereinafter referred to as the lower support portion 44c) have a thinner vertical thickness than other parts of the front arm 40.
[0042] The damper support portion 44 has a fracture-prone portion 45. The fracture-prone portion 45 is the portion that becomes the starting point for fracture when a so-called small overlap collision occurs, in which the portion of the front of the vehicle 1 that is outside the lower frame 20 in the vehicle width direction collides with an obstacle 71 (see Figures 11 to 14). The fracture-prone portion 45 is formed on the front surfaces of the upper support portion 44b and the lower support portion 44c of the damper support portion 44, respectively. In other words, the fracture-prone portion 45 is formed in the portion of the damper support portion 44 other than the hole portion 44a. Each fracture-prone portion 45 is composed of a groove that is recessed in the front-rear direction, and in particular a groove that is recessed in an inverted triangular shape from the front to the rear.
[0043] The easily breakable portion 45 breaks when a load exceeding a predetermined value is applied to the front wheel 3 from the front. When the easily breakable portion 45 breaks, the front wheel 3, along with the front wheel support portion 41, is separated from the suspension arm 33. The predetermined value is slightly smaller than the load that causes the front wheel 3 to retract and contact the rear of the vehicle body during a small overlap collision, and is a load that causes the vehicle body to deform slightly due to the contact of the front wheel 3.
[0044] As shown in Figure 7, the rear surface portion 43a of the outer portion 43 has an arched shape that curves forward in a plan view such that the middle portion in the left-right direction is located in front of both ends in the left-right direction. The foremost curved apex 43b of the rear surface portion 43a is located behind the easily breakable portion 45. Specifically, the left-right position of the curved apex 43b and the left-right position of the easily breakable portion 45 are the same.
[0045] A bar support portion 46 is formed at the upper center of the front arm 40 in the left-right direction, where the anti-roll bar 31 is supported.
[0046] The rear arm 50 has a second vehicle body support portion 51 at its rear end, which is attached to the rear end of the lower frame 20. The second vehicle body support portion 51 is located inward in the vehicle width direction compared to the front wheel support portion 41. The second vehicle body support portion 51 has a second bracket 51a and a second cylindrical member 51b. The second cylindrical member 51b is fixed to the second bracket 51a by welding. Inside the second cylindrical member 51b is a second support shaft (not shown) and a rubber bush (not shown) arranged around the second support shaft. The second support shaft extends parallel to the first support shaft 42c. The second bracket 51a is fixed to the rear end of the lower frame 20 by bolts. With the second bracket 51a fixed to the vehicle body member (in this case, the lower frame 20), the rear arm 50 is rotatable around the support shaft relative to the vehicle body. In particular, since the second support shaft is positioned to extend in the front-rear direction parallel to the first support shaft 42c, the rear arm 50 is rotatable in the vertical direction. As a result, the entire suspension arm 33, which includes the front arm 40 and the rear arm 50, is rotatable in the vertical direction relative to the vehicle body.
[0047] The left front portion of the rear arm 50 has a bulge 52 that extends forward. This bulge 52 allows the lateral width of the rear arm 50 to be maximized, thereby increasing the horizontal bending rigidity of the rear arm 50. Therefore, the bulge 52 helps to suppress the amount of deformation of the rear arm 50 during small overlap collisions.
[0048] The upper surface of the rear arm 50 has a recess 53 that curves downwards, forming almost the entire surface. Although not shown in the illustration, the lower surface of the rear arm 50 also has a recess that curves upwards, forming almost the entire surface.
[0049] The front arm 40 and the rear arm 50 are fixed to each other by a first connecting portion 61 located relatively outward in the vehicle width direction and a second connecting portion 62 located inward in the vehicle width direction compared to the first connecting portion 61. The first connecting portion 61 is located at the right end (outward end in the vehicle width direction) of the rear arm 50, and the second connecting portion 62 is located in the center of the rear arm 50 in the left-right direction.
[0050] As shown in Figure 5, the first connecting portion 61 has a first insertion portion 61b provided on the front arm 40 through which a bolt 61a is inserted, and a first fastening portion 61c provided on the rear arm 50 through which a bolt 61a is fastened. The through hole formed in the first insertion portion 61b is not threaded, and the first insertion portion 61b and the bolt 61a do not screw into each other.
[0051] As shown in Figures 8 and 10, a first recess 61d is formed at the rear end of the first insertion portion 61b, extending forward around the entire circumference of the through hole. On the other hand, as shown in Figures 9 and 10, a first projection 61e is formed at the front end of the first fastening portion 61c, projecting forward at a position corresponding to the first recess 61d. The first projection 61e is formed around the entire circumference of the fastening hole of the first fastening portion 61c. When the front arm 40 is fixed to the rear arm 50, that is, when the bolt 61a is fastened to the first fastening portion 61c, the first projection 61e is housed within the first recess 61d. As a result, even if the front arm 40 and the rear arm 50 move relative to each other in different directions during a small overlap collision, the first protrusion 61e abuts against the wall of the first recess 61d, thereby suppressing the relative movement between the first insertion portion 61b and the first fastening portion 61c. Consequently, during a small overlap collision, shear stress is less likely to be applied to the bolt 61a, and the fixed state of the first connection portion 61 is maintained.
[0052] On the other hand, the second connecting portion 62, like the first connecting portion 61, has a second insertion portion 62b provided on the front arm 40 through which a bolt 62a is inserted, and a second fastening portion 62c provided on the rear arm 50 through which a bolt 62a is fastened. The through hole (not shown) formed in the second insertion portion 62b is not threaded, and the second insertion portion 62b and the bolt 62a do not screw together.
[0053] The second insertion portion 62b of the second connecting portion 62 does not have a recess like the first insertion portion 61b. Also, the second fastening portion 62c of the second connecting portion 62 does not have a protrusion like the first fastening portion 61c.
[0054] Furthermore, the first projection 61e may be integrally formed with the first fastening portion 61c, or it may be formed by fixing a separate sleeve or the like. Also, the first projection 61e may be formed on the first insertion portion 61b, and the first recess 61d may be formed on the first fastening portion 61c. In addition, the first projection 61e does not need to be formed around the entire circumference of the first fastening portion 61c, as long as it is provided on both sides of the bolt 61a in the vehicle width direction, especially on the portion located on the outside of the bolt 61a in the vehicle width direction. Also, similar to the first connecting portion 61, the second connecting portion 62 may have a recess formed on one of the second insertion portion 62b and the second fastening portion 62c, and a projection that protrudes into the recess formed on the other.
[0055] (Behavior of the suspension arm during a small overlap collision) Next, the behavior of the right suspension arm 33 when a small overlap collision occurs with an obstacle 71 on the right front portion of vehicle 1 will be explained with reference to Figures 11 to 14.
[0056] When the obstacle 71 moves further backward relative to the vehicle 1, as shown in Figure 11, the obstacle 71 collides with the right front wheel 3, and a load (collision load) is applied to the front wheel 3 from the front. As a result of the load being applied to the front wheel 3, a load is applied to the front wheel support portion 41 of the suspension arm 33.
[0057] As the obstacle 71 moves further back relative to the vehicle 1, the front wheel support 41 moves backward along with the front wheel 3, as shown in Figure 12. Since the left end of the suspension arm 33 is connected to the vehicle body by the first and second vehicle body mounting parts 42 and 51, when a rearward load is applied to the front wheel 3, the suspension arm 33 deforms in a curved manner so that the right portion is positioned further back. At this time, the portion of the front arm 40 to the left of the first connection part 61 is less likely to deform because the rear arm 50 receives the load. In particular, the first connection part 61 has an uneven structure with a first recess 61d and a first projection 61e that makes it difficult for the bolt 61a to be sheared, so even if the front arm 40 deforms in a curved manner, the connection state of the first connection part 61 is maintained and the load can be received by the rear arm 50. On the other hand, the rear arm 50 is not located behind the outer portion 43 of the front arm 40, and the load is received only by the outer portion 43, so the outer portion 43 is easily deformed. Here, the damper support portion 44 of the outer portion 43 is connected to the vehicle body via the damper 32, making it somewhat resistant to displacement. Therefore, when a rearward load is applied to the front wheel 3, the outer portion 43, especially the portion outside the damper support portion 44, undergoes a large curving deformation toward the rear. As a result, the load is concentrated and input to the easily fractured portion 45 of the damper support portion 44.
[0058] Furthermore, as the suspension arm 33 undergoes curvature, a reaction force F, which includes a lateral component, is applied from the suspension arm 33 to the vehicle body.
[0059] Furthermore, the front wheel 3 contacts the vehicle body (in this case, the right side sill 13) in an obliquely tilted position, with its front end positioned to the right of the rear end, due to the curving deformation of the suspension arm 33.
[0060] Then, as the obstacle 71 moves further back relative to the vehicle 1 and a load exceeding a predetermined value is applied to the easily breakable portion 45, the front arm 40 breaks at the location of the easily breakable portion 45, as shown in Figure 13. As a result, the front wheel 3 is separated from the vehicle body along with the front wheel support portion 41. In addition, the damper support portion 44 breaks, weakening the connection between the damper 32 and the front arm 40.
[0061] Subsequently, as the obstacle 71 moves further backward relative to the vehicle 1, a load is applied to the portion of the suspension arm 33 attached to the vehicle body after the fracture (hereinafter referred to as the remaining portion). Because the connection between this remaining portion and the damper 32 is weakened, it is easily deformed by the load. As a result, a lateral force (the lateral component of the reaction force F) is applied to the vehicle body, causing it to move laterally away from the front wheel 3, resulting in the vehicle body moving laterally (so-called glans-off). Furthermore, because the front wheel 3 is separated from the vehicle body, is angled, and its rear end is in contact with the vehicle body, when a rearward load is applied, it moves to rotate to the right with the contact point with the vehicle body as the pivot point. As a result, the front wheel 3 and the vehicle body move apart from each other.
[0062] Even if a small overlap collision occurs on the left side of the front of vehicle 1, and a collision load is applied to the left front wheel 3 from the front, the left suspension arm 33 will bend and deform in the same way as the right suspension arm 33, and the left front arm 40 will break at the easily breakable section 45, causing the left front wheel 3 and the vehicle body to move away from each other.
[0063] Therefore, even if the front wheel 3 moves backward, deformation of the vehicle body members by the front wheel 3 is suppressed, thus suppressing deformation of the vehicle body during a small overlap collision.
[0064] (summary) Therefore, in this embodiment, the suspension arm 33 is provided with a front wheel support portion 41 at one end that supports the front wheel 3 of the vehicle 1, and first and second body mounting portions 42 and 51 at the other end that are attached to the body member of the vehicle 1 so as to be located inward in the vehicle width direction from the front wheel support portion 41. The damper 32 is supported by a damper support portion 44 provided near the front wheel support portion 41 on the suspension arm 33 and is connected to the vehicle body at its upper part, and the damper support portion 44 has a fracture-friendly portion 45. With this configuration, when a load is applied to the front wheel support portion 41 via the front wheel 3 during a small overlap collision, the suspension arm 33 bends and deforms, and fractures at the fracture-friendly portion 45. As a result, the front wheel 3 is separated from the vehicle body, while a lateral force is applied to the vehicle body due to the reaction force from the suspension arm 33. As a result, the front wheel 3 and the vehicle body move away from each other, so even if the front wheel 3 moves backward, deformation of the vehicle body member by the front wheel 3 is suppressed. Therefore, it is possible to suppress the deformation of the vehicle body during small overlap collisions.
[0065] Furthermore, in this embodiment, the damper support portion 44 has a hole 44a that accommodates the lower end of the damper 32 and penetrates in the front-rear direction, and the easily fractured portion 45 is provided in the portion of the damper support portion 44 other than the hole 44a. As a result, the portion where the easily fractured portion 45 is provided is relatively thinner compared to the other portion of the suspension arm 33. This makes it easier for the suspension arm to fracture starting from the easily fractured portion 45 during a small overlap collision, thereby more effectively suppressing deformation of the vehicle body during a small overlap collision.
[0066] Furthermore, in this embodiment, the easily fractured portion 45 is provided on both the upper support portion 44b above the hole portion 44a and the lower support portion 44c below the hole portion 44a of the damper support portion 44. As a result, in the event of a small overlap collision, the suspension arm 33 is more likely to fracture with the easily fractured portion 45 as the pivot point, thereby more effectively suppressing the deformation of the vehicle body during a small overlap collision.
[0067] Furthermore, in this embodiment, the easily fractured portion 45 is a groove that is recessed in the longitudinal direction of the vehicle. This makes it easier for the suspension arm 33 to fracture with the easily fractured portion 45 as the pivot point when a collision load from the front to the rear is applied to the suspension arm 33 during a small overlap collision. This makes it possible to more effectively suppress the deformation of the vehicle body during a small overlap collision.
[0068] Furthermore, in this embodiment, the rear surface portion 43a of the outer portion 43 of the suspension arm 33 has an arched shape that curves toward the front when viewed from above. As a result, the outer portion 43 is more likely to deform in a way that causes the front portion to bend into a mountain shape due to the impact load of a small overlap collision. Therefore, if a fracture-prone portion 45 is provided in the damper support portion 44, the suspension arm 33 is more likely to break with the fracture-prone portion 45 as the pivot point. This makes it possible to more effectively suppress the deformation of the vehicle body during a small overlap collision.
[0069] Furthermore, in this embodiment, the easily fractured portion 45 is a groove formed on the front surface of the damper support portion 44 and recessed in the front-rear direction. As a result, when the front surface deforms in a way that causes it to fold like a mountain, the easily fractured portion 45 is particularly likely to become the starting point for fracture. This makes it possible to more effectively suppress the deformation of the vehicle body during a small overlap collision.
[0070] In particular, in this embodiment, the position of the easily fractured portion 45 in the vehicle width direction is the same as the position of the curved apex 43b located on the frontmost side of the rear portion 43a in the vehicle width direction. As a result, the front portion is particularly prone to mountain-fold deformation at the position of the easily fractured portion 45, making the easily fractured portion 45 more likely to become the starting point for fracture. This makes it possible to more effectively suppress the deformation of the vehicle body during a small overlap collision.
[0071] Furthermore, in this embodiment, the suspension arm 33 has a front arm 40 that extends straight in the vehicle width direction, and a rear arm 50 that is located behind the front arm 40 and fixed to the front arm 40, with the outer end of the rear arm 50 in the vehicle width direction being located inward in the vehicle width direction compared to the damper support portion 44. As a result, in the event of a small overlap collision, the outer portion 43 of the front arm 40, including the damper support portion 44, is considerably more prone to deformation than the portion of the front arm 40 that is inward in the vehicle width direction compared to the outer portion 43. This makes it easier to cause the suspension arm 33 to break at the easily breakable portion 45 during a small overlap collision. In addition, since the remaining portion of the suspension arm 33 after breakage is less prone to buckling, the lateral force due to the compressive deformation of the remaining portion can be effectively exerted. As a result, the deformation of the vehicle body during a small overlap collision can be suppressed more effectively.
[0072] Furthermore, in this embodiment, both the front arm 40 and the rear arm 50 of the suspension arm 33 are formed by forging. This increases the overall rigidity of the suspension arm 33, thereby significantly improving its support performance under normal conditions. Additionally, if the overall rigidity of the suspension arm 33 is high, it becomes easier for the fracture to occur at points where the rigidity is reduced compared to the surrounding area, such as the easily fractured portion 45. Moreover, since the remaining portion of the suspension arm 33 is less likely to buckle after fracture, the lateral force due to the compressive deformation of the remaining portion can be effectively exerted, thereby more effectively suppressing the deformation of the vehicle body during a small overlap collision.
[0073] (Other embodiments) The technologies disclosed herein are not limited to the embodiments described above and may be substituted insofar as they do not depart from the spirit of the claims.
[0074] For example, in the embodiment described above, the easily fractured portion 45 was formed on the front surface of the damper support portion 44, but it is not limited to this and may be formed on the rear surface of the damper support portion 44. In this configuration, during a small overlap collision, the front surface of the suspension arm 33 is more likely to bend at the location of the easily fractured portion 45, and a load is applied to the front of the damper support portion 44 during deformation. As a result, the suspension arm 33 is torn apart at the location of the damper support portion 44. Therefore, even in this configuration, the suspension arm 33 can be fractured with the easily fractured portion 45 as the pivot point.
[0075] Furthermore, in the above-described embodiment, the easily fractured portion 45 was formed on both the upper support portion 44b and the lower support portion 44c, but the configuration is not limited to this, and the easily fractured portion 45 may be formed on only one of the upper support portion 44b or the lower support portion 44c. In this configuration as well, if the part of the upper support portion 44b or the lower support portion 44c that has the easily fractured portion 45 fractures, a large load will be placed on the other part, and it will eventually fracture as well.
[0076] Furthermore, in the above-described embodiment, the rear surface portion 43a of the outer portion 43 of the front arm 40 had an arched shape that curved toward the front when viewed from above. However, the rear surface portion 43a may extend straight in the vehicle width direction.
[0077] The embodiments described above are merely illustrative and should not be interpreted as limiting the scope of this disclosure. The scope of this disclosure is defined by the claims, and any variations or modifications within the equivalent scope of the claims are all within the scope of this disclosure. [Industrial applicability]
[0078] The technology disclosed herein is useful as a front suspension system for minimizing vehicle body deformation during small overlap collisions. [Explanation of Symbols]
[0079] 1 vehicle 3 Front wheels 13 Side sill 20 Lower arm (body component to which the body mounting part is attached) 30 Suspension System 32 dampers 33 Suspension Arm 41 Front wheel support part 42 First body mounting section 43 Outer part 43a Rear part 43b Curved apex 44 Damper support section 44a hole 45. Easily breakable portion 51 Second body mounting section
Claims
1. Front suspension system, A suspension arm having a front wheel support portion at one end for supporting the front wheel of the vehicle, and a body mounting portion at the other end that is attached to a vehicle body member so as to be located inward in the vehicle width direction from the front wheel support portion, The suspension arm comprises a damper supported by a damper support provided near the front wheel support and connected to a vehicle body member at its upper end, The front suspension device is characterized in that the damper support portion has a portion that is easily broken.
2. In the front suspension device according to claim 1, The damper support portion has a hole that accommodates the lower end of the damper and penetrates in the longitudinal direction of the vehicle. The front suspension device is characterized in that the easily breakable portion is provided in a portion of the damper support other than the hole portion.
3. In the front suspension device according to claim 2, The front suspension device is characterized in that the easily breakable portion is provided in both the portion above and the portion below the hole in the damper support portion.
4. In the front suspension device according to claim 1, The front suspension device is characterized in that the easily breakable portion is a groove that is recessed in the longitudinal direction of the vehicle.
5. In the front suspension device according to claim 1, The front suspension device is characterized in that the rear surface of the outer portion of the suspension arm, which is the portion from the damper support to the front wheel support, has an arched shape that curves toward the front of the vehicle when viewed from above.
6. In the front suspension device according to claim 5, The front suspension device is characterized in that the easily breakable portion is a groove formed on the front surface of the damper support portion and recessed in the longitudinal direction of the vehicle.
7. In the front suspension device according to claim 6, A front suspension device characterized in that the position of the easily breakable portion in the vehicle width direction is the same as the position in the vehicle width direction of the curved apex located furthest forward on the rear surface.
8. In the front suspension device according to any one of claims 1 to 7, A front suspension system characterized in that the suspension arm is formed by forging.