JP7715085B2 - Suspension structure - Google Patents

Description

The present invention relates to a suspension structure equipped with a suspension member that supports a lower arm so that it can swing freely.

A conventional suspension structure known in the art includes a suspension member that swingably supports a lower arm, a stabilizer that connects the left and right suspension members to suppress roll, and a steering gearbox that transmits steering input from the steering shaft to steer the wheels (see, for example, Patent Document 1).

In order to reduce weight, the suspension members in such general suspension structures are constructed as hollow bodies rather than solid bodies. Specifically, they are typically formed by joining multiple divided members to form a hollow structure that extends in the vehicle width direction between the left and right wheels (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 2007-131221 Japanese Patent Application Laid-Open No. 2000-344130

In conventional vehicles, including those described in Patent Documents 1 and 2, it is common to design each component that makes up the suspension structure separately; for example, the steering gearbox, which is a chassis component, is designed as a standalone unit, and the suspension members, which are body components, are designed as standalone units.

This is because conventional design methods are based on the idea that the optimal suspension structure can be achieved by combining optimal parts (suspension members, stabilizers, steering gearboxes, etc.) that are designed individually.

However, while this conventional design method can be evaluated as the optimal design method when viewed as a single steering gearbox or suspension member, it is difficult to say that it is the optimal design method when viewed as the entire suspension structure.

For example, Patent Document 2 aims to reduce the weight of suspension members by using bending instead of drawing to reduce plate thickness, and by joining the edges of divided members in an abutting (or overlapping) state, thereby eliminating the need for flanges. However, such innovations in the suspension member alone are unlikely to result in significant weight and cost reductions for the entire suspension structure.

Furthermore, if the steering gearbox is assembled (attached) to the suspension member, the stiffness of the entire suspension structure in the vehicle width direction will increase, but this has not been taken into account in the design to reduce the stiffness of the suspension member alone in the vehicle width direction (to reduce weight and cost).

As such, the conventional design method of separately designing each component that makes up the suspension structure is hardly the optimal design method, particularly from the perspective of reducing weight and cost, and there is room for improvement.

The present invention was made in light of these issues, and its purpose is to provide a suspension structure that can achieve significant weight and cost reductions while maintaining the functionality required of a suspension.

To achieve the above objective, the suspension structure of the present invention boldly omits all parts of the suspension member, leaving only the part that supports the lower arm and the part that is attached to the vehicle body, and each part that makes up the suspension structure is treated as if it were a single component.

Specifically, the present invention relates to a suspension structure comprising a suspension member and a steering gearbox for steering the wheels.

The suspension structure includes left and right suspension members as the suspension members, spaced apart in the vehicle width direction and attached to the vehicle body at both ends in the vehicle width direction, and supporting the left and right lower arms so that they can swing freely, the left suspension member and the right suspension member being connected via the steering gearbox extending in the vehicle width direction, and further including stabilizers supported on the left and right suspension members via support members, forward of the steering gearbox in the vehicle longitudinal direction, the left and right suspension members having a pair of left and right mounting portions on the front and rear sides in the vehicle longitudinal direction, the rear mounting portion being bolted directly to the left and right suspension members in the vertical direction, and the front mounting portion being attached to the left and right suspension members via the support members, and the front mounting portion being configured to be bolted to the support members in the vertical or lateral direction .

This configuration leaves only the left and right suspension members that are attached to the vehicle body and support the left and right lower arms so that they can swing freely, while boldly eliminating the area between these left and right suspension members, thereby achieving significant weight and cost reductions for the entire suspension structure.

In this way, the left and right suspension members, which are spaced apart in the vehicle width direction, are connected via the steering gearbox, which extends in the vehicle width direction, without adding any new components. This allows for significant weight and cost reductions, while also allowing the steering gearbox to compensate for the rigidity and other requirements in the vehicle width direction that were previously provided by the omitted parts.

In this way, with the suspension structure of the present invention, each component that makes up the suspension structure (suspension member and steering gearbox) is treated as if it were a single part, and by compensating for any missing parts (functions), it is possible to achieve significant weight and cost reductions while maintaining the functions required of the suspension.
Furthermore, in this configuration, for example, if both of the pair of left and right front mounting portions are bolted to the support member in the vertical direction, in other words, if all four front and rear mounting portions are bolted in the vertical direction, the ease of assembly of the steering gear box can be improved.
On the other hand, for example, in an engine vehicle, various devices are arranged in the engine compartment in front of the steering gear box in the vehicle longitudinal direction, and by appropriately setting the bolt fastening direction of the front mounting part to the vertical or horizontal direction, interference between the support members, bolts, etc. and the devices in the engine compartment can be reduced.

While it is possible to maintain the required suspension functionality with the above configuration, in which the left and right suspension members are connected via the steering gearbox, the height at which the reaction force from the tires is received (the support height of the lower arm) differs from the height at which the left and right suspension members are connected (the installation height of the steering gearbox), which could result in a bending moment being generated in the left and right suspension members. Therefore, from the perspective of vehicle handling stability, it is preferable to connect the left and right suspension members at a height as close as possible to the height at which the reaction force from the tires is received.

Adding a reinforcing member here would increase weight and cost, and would undermine the point of omitting the section between the left and right suspension members, but if an existing part is located near the suspension members, there is no reason not to use it.

Therefore, in the above suspension structure, braces for supporting an undercover that covers the underside of the vehicle floor may be attached to the left and right suspension members from below.

Vehicles are typically equipped with under-floor braces to streamline the airflow while driving and improve fuel economy. With this configuration, the existing braces used to support the under-covers are attached to the left and right suspension members from below, thereby increasing planar rigidity near the height at which the lower arms are supported (where they receive reaction force from the tires).

In this way, by utilizing existing braces, it is possible to improve the vehicle's handling stability while maintaining significant weight and cost reductions.

In an engine vehicle, the engine is typically connected to the center of the suspension member in the vehicle width direction via a torque rod to suppress the engine's driving reaction force. However, this configuration is not possible with a suspension structure that omits the section between the left and right suspension members.

In the above suspension structure, a torque rod mounting portion for mounting a torque rod connected to the engine is formed in the center of the steering gearbox in the vehicle width direction, and the torque rod may be sandwiched between the torque rod mounting portion and the brace from above and below.

With this configuration, even in a structure that omits the section between the left and right suspension members, the torque rod can be firmly supported without adding any new components, with a simple structure in which the torque rod is sandwiched above and below by the torque rod mounting portion and the brace, thereby suppressing the engine's driving reaction force.

Furthermore, in the above suspension structure, the left and right suspension members may be configured as solid members made of aluminum die-cast.

This configuration uses a solid suspension member made of die-cast aluminum, which has higher rigidity than hollow suspension members, thereby increasing the rigidity of force application points, such as the support points of the lower arm and the vehicle body mounting points.

Furthermore, even if solid aluminum die-cast suspension members, which are heavier than hollow steel suspension members, are used, the section between the left and right suspension members is omitted, so the weight of the entire suspension structure can be kept from increasing.

As described above, in the suspension structure of the present invention, the left and right suspension members, which are spaced apart in the vehicle width direction, are connected by a roughly rod-shaped steering gearbox and a flat beam-shaped brace. Looking at it from another perspective, this means that the left and right suspension members, which are spaced apart in the vehicle width direction, are connected in the vehicle width direction by a skeletal member.

Therefore, the present invention provides a suspension structure comprising a suspension member,
The suspension member can also be defined as being composed of left and right suspension members that are spaced apart in the vehicle width direction, attached to the vehicle body at both ends in the vehicle width direction, and supporting the left and right lower arms respectively so that they can swing freely, and the left suspension member and the right suspension member are connected in the vehicle width direction via a skeletal member.

As described above, the suspension structure of the present invention allows for significant weight and cost reductions while maintaining the functionality required of a suspension.

1 is a perspective view schematically showing a suspension structure according to a first embodiment of the present invention; FIG. 2 is an exploded perspective view illustrating a suspension structure and a mounting method thereof to a vehicle body. FIG. 1 is a perspective view schematically illustrating a suspension structure according to a first modified example of the first embodiment. FIG. 10 is a perspective view schematically illustrating a suspension structure according to a second modification of the first embodiment. FIG. 10 is a perspective view schematically showing a suspension structure according to a second embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating a suspension structure and a mounting method thereof to a vehicle body. FIG. 10 is a perspective view schematically showing a suspension structure according to a modified example of the second embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In each drawing, the arrow Fw indicates the front side in the longitudinal direction of the vehicle, the arrow Lf indicates the left side in the width direction of the vehicle, and the arrow Up indicates the top side in the vertical direction.

(Embodiment 1)
Fig. 1 is a perspective view showing a suspension structure according to this embodiment, and Fig. 2 is an exploded perspective view showing the suspension structure and its attachment to a vehicle body. Note that, for ease of viewing, Fig. 2 shows only the right suspension member 50 of the suspension members, and omits some of the beams that make up the brace 30.

This suspension structure is applied to the front suspension of vehicles equipped with engines, such as so-called conventional vehicles and hybrid vehicles. As shown in Figure 1, this suspension structure includes suspension members 40, 50 that connect the front wheels (not shown) to the vehicle body (front side member 90), a steering gearbox 10 for steering the front wheels, a stabilizer bar 20 for suppressing roll, and a brace 30 for supporting an undercover (not shown).

- Suspension member -
1, the suspension member is made up of a left suspension member 40 and a right suspension member 50 that are spaced apart in the vehicle width direction. In other words, unlike typical suspension members that extend in the vehicle width direction between the left and right front wheels, the suspension member of this embodiment is configured by boldly omitting the portion between the left suspension member 40 and the right suspension member 50. Furthermore, unlike typical suspension members that are configured as hollow structures made of iron, the left and right suspension members 40, 50 are both configured as solid members made of aluminum die-cast.

The left and right suspension members 40, 50 each include a main body portion 41, 51, a front support portion 42, 52, a rear support portion 43, 53, a front mounting portion 44, 54, and a rear mounting portion 45, 55. They are attached to the front side members 90 at both ends in the vehicle width direction, and support the left and right lower arms 81, 83, respectively, so that they can swing freely. Because the left suspension member 40 and the right suspension member 50 are formed symmetrically, the following description will focus on the right suspension member 50 as a representative.

The main body 51 extends in the fore-and-aft direction of the vehicle at approximately the same height as the right lower arm 83. As shown in FIG. 2, the main body 51 is formed so that the portion 51b to which the steering gearbox 10 is attached is higher than the portion 51a to which the bracket 25 of the stabilizer 20 is attached. Two bolt holes that penetrate vertically are formed in the relatively lower portion 51a, so that the bracket 25 of the stabilizer 20 is fastened with bolts. In addition, the relatively higher portion 51b is formed with a front bolt hole 51c and a rear bolt hole 51d that penetrate vertically, so that the steering gearbox 10 is fastened with bolts 18, 19.

The front support portion 52 is provided at the front end of the main body portion 51 and supports the right lower arm 83 via a lower arm bushing (not shown) so that it can swing freely around an axis extending in the fore-and-aft direction of the vehicle. Meanwhile, the rear support portion 53 is provided at the rear end of the main body portion 51 and supports the right lower arm 83 via a lower arm bushing (not shown) so that it can swing freely around an axis extending in the up-down direction. This allows the lower arm bushing of the rear support portion 53 to prevent prying forces from acting on the lower arm bushing of the front support portion 52, while the lower arm bushing of the front support portion 52 absorbs impacts received by the tire (front wheel) and allows the front wheel to be displaced in the up-down direction relative to the vehicle body.

As shown in FIG. 2 , the right suspension member 50 is attached to the front side member 90 at front and rear mounting portions 54, 55. More specifically, the front side member 90 has a front portion 91 extending in the longitudinal direction of the vehicle and a rear portion 93 that is lower than the front portion 91 and extends in the longitudinal direction of the vehicle on the inner side in the vehicle width direction. The front mounting portion 54 extends from the rear of the front support portion 52 of the main body portion 51, sloping upward as it extends outward in the vehicle width direction (to the right), and its upper end is bolted to the front portion 91 of the front side member 90 from below. Meanwhile, the rear mounting portion 55 extends further rearward from the rear support portion 53 of the main body portion 51, and its rear end is bolted to the rear portion 93 of the front side member 90 from below.

- Steering gear box -
1, the steering gearbox 10 is part of an electric power steering system that assists the steering operation of the driver, and includes a housing 11 extending in the vehicle width direction, a pinion shaft 12 connected to a steering shaft (not shown), a tie rod 13, and a boot 14 that covers the portion of the tie rod 13 that extends from the housing 11. The steering gearbox 10 is connected to a steering wheel (not shown) via the steering shaft, and is configured to convert a rotational displacement input to the steering wheel by the driver's steering operation and to which an assist torque is added by an electric motor (not shown) into a displacement of the tie rod 13 in the vehicle width direction, thereby changing the direction of the front wheels.

In this embodiment, the electric power steering system is a column assist type in which an electric motor and reduction gear (not shown) are provided on the column section of the steering shaft inside the vehicle cabin to drive the column shaft. However, this is not limited to this, and a pinion assist type in which an electric motor is provided on the housing 11 to drive a pinion gear (not shown) may also be used.

The steering gearbox 10 has a pair of left and right mounting portions 15, 16 on the front and rear sides in the longitudinal direction of the vehicle. Specifically, as shown in FIG. 2, a pair of left and right front mounting portions 15 are provided on the front side of the housing 11 of the steering gearbox 10 in the longitudinal direction of the vehicle at positions corresponding to portions 51b (front bolt holes 51c) of the main bodies 41, 51 of the left and right suspension members 40, 50. Furthermore, as shown in FIGS. 1 and 2, a pair of left and right rear mounting portions 16 are provided on the rear side of the housing 11 of the steering gearbox 10 in the longitudinal direction of the vehicle at positions corresponding to portions 51b (rear bolt holes 51d) of the main bodies 41, 51 of the left and right suspension members 40, 50.

The pair of left and right front mounting portions 15 and the pair of left and right rear mounting portions 16 each have a bolt hole formed therethrough in the vertical direction. The pair of left and right front mounting portions 15 are directly fastened in the vertical direction to the left and right suspension members 40, 50 by bolts 18 inserted into the front bolt holes 51c, and the pair of left and right rear mounting portions 16 are fastened in the vertical direction to the left and right suspension members 40, 50 by bolts 19 inserted into the rear bolt holes 51d. In other words, the steering gearbox 10 is fastened (supported) to the left and right suspension members 40, 50 at four points via the bolts 18, 19.

As a result, in the steering structure of this embodiment, the left suspension member 40 and the right suspension member 50 are connected via the steering gearbox 10, which extends in the vehicle width direction. In other words, in the steering structure of this embodiment, the steering gearbox 10 functions as a framework member that connects the left suspension member 40 and the right suspension member 50 in the vehicle width direction.

Furthermore, as shown in Figures 1 and 2, a torque rod mounting portion 17 having a bolt hole passing through in the vertical direction is formed in the center of the housing 11 of the steering gearbox 10 in the vehicle width direction for mounting a torque rod 85 connected to the engine (not shown).

-Stabilizer-
The stabilizer 20 has a torsion bar 21 extending in the vehicle width direction, and arms 22 bent in a generally L-shape from both ends of the torsion bar 21 in the vehicle width direction and extending forward in the vehicle longitudinal direction, with the tips of the arms 22 connected to the left and right lower arms 81, 83 via bushings (not shown). When a difference occurs between the left and right stroke amounts during cornering, for example, torsional stress is generated in the torsion bar 21, and the restoring force of this stress corrects the left and right stroke amounts in the same direction, thereby suppressing rolling and maintaining horizontal stability.

The stabilizer 20 is supported by the left and right suspension members 40, 50 via brackets 25, located further forward in the vehicle longitudinal direction than the steering gearbox 10. More specifically, a pair of left and right stabilizer bushings 23 are fitted to the torsion bar 21 of the stabilizer 20. Brackets 25 are attached to cover these stabilizer bushings 23, and are bolted to portions 51a of the main bodies 41, 51, respectively, so that the stabilizer 20 is supported by the left and right suspension members 40, 50.

-Brace-
The brace 30 suspends and supports an undercover (not shown) that covers the underfloor of the vehicle to rectify the airflow under the floor. As shown in Figure 2, the brace 30 is attached to the left and right suspension members 40, 50 from below by fastening a portion of it with dedicated bolts 35 and a portion of it together with bolts 18 for fastening the steering gearbox 10.

In this way, by attaching the brace 30 to the left and right suspension members 40, 50 from below, it is possible to increase the planar rigidity of the suspension structure near the height at which the left and right lower arms 81, 83 are supported (receiving reaction forces from the tires). The brace 30 is not simply flat, but is formed in a shape that combines a minimum number of beams, such as a generally linear beam 31 extending in the vehicle width direction and a generally linear beam 32 extending diagonally, as shown in FIG. 1, taking into account the direction of forces acting on the left and right suspension members 40, 50, thereby reducing its weight. In this way, in the steering structure of this embodiment, the brace 30, in addition to the steering gearbox 10, also functions as a skeletal member that connects the left suspension member 40 and the right suspension member 50 in the vehicle width direction.

In addition, because the braces 30 are attached to the left and right suspension members 40, 50 from below, the torque rod 85 connected to the engine is firmly supported by being sandwiched between the torque rod mounting portion 17 of the steering gearbox 10 and the braces 30 from above and below.

-Actions and Effects-
According to this embodiment, the left and right suspension members 40, 50 that are attached to the front side member 90 and that support the left and right lower arms 81, 83, respectively, so as to be freely swingable, are left, and the portion between these left suspension member 40 and right suspension member 50 is boldly omitted. This makes it possible to achieve significant weight and cost reductions compared to when suspension members that extend in the vehicle width direction between the left and right front wheels are used.

Furthermore, the left and right suspension members 40 and 50, which are spaced apart in the vehicle width direction, are connected via the steering gear box 10, which extends in the vehicle width direction, without adding any new components. This allows for significant weight and cost reductions, while allowing the steering gear box 10 to compensate for the rigidity and other requirements in the vehicle width direction that were previously provided by the omitted parts.

In this way, with the suspension structure of this embodiment, the left and right suspension members 40, 50 support the left and right lower arms 81, 83 so that they can swing freely, the steering gearbox 10 changes the direction of the front wheels, the stabilizer 20 suppresses rolling, and the brace 30 suspends and supports the undercover, thereby enabling significant weight and cost reductions while maintaining the functionality required of a suspension.

Here, it is possible to maintain the required suspension functionality simply by connecting the left suspension member 40 and the right suspension member 50 via the steering gearbox 10. However, with the suspension structure of this embodiment, the height at which reaction force from the tires is received (the support height of the left and right lower arms 81, 83) is different from the height at which the left and right suspension members 40, 50 are connected (the installation height of the steering gearbox 10), so a bending moment may occur in the left and right suspension members 40, 50.

From the perspective of vehicle handling stability, it is therefore preferable to connect the left suspension member 40 and the right suspension member 50 at a height as close as possible to the height at which they receive reaction force from the tires. In this embodiment, however, the brace 30 for supporting the undercover is attached to the left and right suspension members 40, 50 from below, thereby increasing planar rigidity near the height at which the left and right lower arms 81, 83 are supported (receive reaction force from the tires).

In this way, by utilizing the brace 30 that is normally provided to suspend and support the undercover to improve fuel economy, it is possible to improve the vehicle's handling stability while maintaining significant weight and cost savings, without having to take the trouble of adding a new reinforcing member.

In addition, because the torque rod 85 is sandwiched between the torque rod mounting portion 17 of the steering gearbox 10 and the brace 30, the torque rod 85 can be firmly supported without adding any new components, even in a structure that omits the section between the left suspension member 40 and the right suspension member 50, thereby suppressing the engine's driving reaction force.

Furthermore, by using solid suspension members 40, 50 made of die-cast aluminum, which have higher rigidity than hollow suspension members, it is possible to increase the rigidity of the force application points at the front support portions 42, 52 and rear support portions 43, 53, which are support points for the lower arms 81, 83, the front mounting portions 44, 54 and rear mounting portions 45, 55, which are attachment points to the front side member 90, and the main body portions 41, 51, which are attachment points for the steering gearbox 10.

Furthermore, even when using solid aluminum die-cast suspension members 40, 50, which are heavier than hollow steel suspension members, the omission of the section between the left suspension member 40 and the right suspension member 50 prevents the vehicle weight from increasing.

(Variation 1)
This modified example differs from the first embodiment in the manner in which the steering gear box is attached to the left and right suspension members. The following description will focus on the differences from the first embodiment.

Figure 3 is a perspective view schematically showing a suspension structure according to this modified example. In the first embodiment, as described above, the front mounting portion 15 and rear mounting portion 16 of the steering gearbox 10 are bolted directly to the left and right suspension members 40, 50 in the vertical direction. In contrast, in this modified example, as shown in Figure 3, like the first embodiment, the rear mounting portion 16 of the steering gearbox 10' is bolted directly to the left and right suspension members 40', 50' in the vertical direction. However, unlike the first embodiment, the front mounting portions 15A, 15B of the steering gearbox 10' are bolted to the left and right suspension members 40', 50' via brackets 26, 27.

More specifically, the left and right suspension members 40', 50' have substantially the same configuration as the left and right suspension members 40, 50 described above, except that they do not have the front bolt holes 51c.

As shown in FIG. 3, the steering gear box 10' has substantially the same configuration as the steering gear box 10, except that front mounting portions 15A and 15B are formed on the housing 11' instead of the front mounting portion 15. The front mounting portions 15A and 15B are formed to protrude forward in the vehicle longitudinal direction from the housing 11' and extend above the stabilizer bar 20. The front mounting portion 15A has a bolt hole that penetrates in the vehicle width direction, while the front mounting portion 15B has a bolt hole that penetrates in the vertical direction.

Furthermore, like bracket 25, bracket 26 is attached so as to cover stabilizer bushing 23 and is bolted to the left suspension member 40', but unlike bracket 25, it has an attachment portion 26a that protrudes upward and has a bolt hole that penetrates in the vehicle width direction. Furthermore, like bracket 25, bracket 27 is attached so as to cover stabilizer bushing 23 and is bolted to the right suspension member 50', but unlike bracket 25, it has an attachment portion 27a that protrudes inward in the vehicle width direction (left side) and has a bolt hole that penetrates in the vertical direction.

As shown in Figure 3, the steering gearbox 10' is supported at four points by the left and right suspension members 40', 50'. The rear mounting portion 16 is bolted directly to the left and right suspension members 40', 50' in the vertical direction, the front mounting portion 15A is bolted laterally to the mounting portion 26a of the bracket 26, and the front mounting portion 15B is bolted vertically to the mounting portion 27a of the bracket 27.

-Actions and Effects-
In a vehicle equipped with an engine, various devices are arranged in the engine room located in front of the steering gear box 10' in the vehicle's fore-and-aft direction. According to this modified example, by omitting the bolt 18 and setting the bolt fastening direction of the front mounting portion 15A to the horizontal direction, it is possible to reduce interference between the bracket 26, bolts, etc. and the devices in the engine room.

(Variation 2)
This modified example differs from the first embodiment in that the suspension structure does not include the brace 30. The following description will focus on the differences from the first embodiment.

Figure 4 is a perspective view showing a schematic diagram of a suspension structure according to this modified example. This suspension structure is applicable to the front suspension of a vehicle without an engine, such as an electric vehicle. Naturally, a vehicle without an engine does not require the torque rod 85 (there is no need to sandwich the torque rod 85 between the steering gearbox 10 and the brace 30 from above and below), so the brace 30 is omitted from the suspension structure according to this modified example.

As a result, the suspension structure of this modified example has a simple structure in which the stabilizer 20 is supported via a bracket 25 on left and right suspension members 40, 50 that are spaced apart in the vehicle width direction and connected via the steering gear box 10, as shown in Figure 4.

Note that this modified example differs from the suspension structure in that it does not include a brace 30; it does not negate the possibility that the vehicle may include a brace 30 for supporting the undercover.

-Actions and Effects-
According to this embodiment, even in vehicles that do not have an engine, such as electric vehicles, it is possible to achieve significant weight and cost reductions in the entire suspension structure while maintaining the functions required of the suspension.

(Embodiment 2)
This embodiment differs from the first embodiment in that the left and right suspension members are made of hollow iron members. The following description will focus on the differences from the first embodiment.

Figure 5 is a perspective view showing the suspension structure according to this embodiment, and Figure 6 is an exploded perspective view showing the suspension structure and its attachment to the vehicle body. The left and right suspension members 60, 70 are hollow structures extending in the vehicle width direction, made by joining together multiple drawn or bent steel plates.

As shown in Figure 5, the left and right suspension members 60, 70 each include a main body 61, 71, a front support portion 62, 72, a rear support portion 63, 73, a front mounting portion 64, 74, and a rear mounting portion 65, 75. The main body 61, front support portion 62, rear support portion 63, front mounting portion 64, and rear mounting portion 65 of the left suspension member 60 have the same configuration as the main body 41, front support portion 42, rear support portion 43, front mounting portion 44, and rear mounting portion 45 of the left suspension member 40, respectively, except for the difference between hollow and solid bodies, and therefore will not be described here. Furthermore, the main body 71, front support portion 72, rear support portion 73, front mounting portion 74, and rear mounting portion 75 of the right suspension member 70 have the same configuration as the main body 51, front support portion 52, rear support portion 53, front mounting portion 54, and rear mounting portion 55 of the right suspension member 50, except for the difference between a hollow body and a solid body, so their description will be omitted.

As shown in FIG. 6, the upper ends of the front mounting portions 74 of the left and right suspension members 60, 70 are bolted from below to the front portions 91 of the front side members 90, and the rear ends of the rear mounting portions 75 are bolted from below to the rear portions 93 of the front side members 90. As shown in FIG. 5, the front support portions 62, 72 of the left and right suspension members 60, 70 support the left and right lower arms 81, 83 for swinging motion around axes extending in the fore-and-aft direction of the vehicle, while the rear support portions 63, 73 support the left and right lower arms 81, 83 for swinging motion around axes extending in the up-and-down direction.

Furthermore, as shown in FIG. 6, the steering gearbox 10 is supported at four points by the left and right suspension members 60, 70, with the front mounting portion 15 and rear mounting portion 16 fastened to the main bodies 61, 71 via bolts 18, 19. The stabilizer 20 is supported by the main bodies 61, 71 of the left and right suspension members 60, 70 via brackets 25. Furthermore, the brace 30 is attached to the left and right suspension members 60, 70 from below.

-Actions and Effects-
According to this embodiment, the left and right suspension members 60, 70 are left, and the portion between the left suspension member 60 and the right suspension member 70 is boldly omitted. This makes it possible to achieve a significant reduction in weight and cost for the entire suspension structure compared to when a hollow iron suspension member extending in the vehicle width direction between the left and right front wheels is used.

(Modification)
This modified example differs from the second embodiment in the manner in which the steering gear box is attached to the left and right suspension members. The following description will focus on the differences from the second embodiment.

Figure 7 is a perspective view showing a schematic diagram of a suspension structure according to this modified example. In this modified example, as shown in Figure 7, the rear mounting portion 16 of the steering gearbox 10' is bolted directly to the left and right suspension members 60', 70' in the vertical direction, while the front mounting portions 15A, 15B of the steering gearbox 10' are bolted to the left and right suspension members 60', 70' via brackets 26, 27.

More specifically, the left and right suspension members 60', 70' have the same configuration as the left and right suspension members 60', 70' described above, except that they do not have front bolt holes corresponding to the front mounting portion 15 of the steering gearbox 10. The steering gearbox 10' is supported at four points by the left and right suspension members 60', 70'. The rear mounting portion 16 is bolted directly to the left and right suspension members 60', 70' in the vertical direction, and the front mounting portion 15A is bolted laterally to the mounting portion 26a of the bracket 26, as shown in FIG. 7, and the front mounting portion 15B is bolted vertically to the mounting portion 27a of the bracket 27.

This modification can achieve the same effects as Modification 1 of Embodiment 1 above.

(Other embodiments)
The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main characteristics thereof.

In the above embodiments, the suspension structure of the present invention is applied to a front suspension, but this is not limiting, and the suspension structure of the present invention may also be applied to a rear suspension.

In addition, in the above-described variant 1 of embodiment 1 and variant 2 of embodiment 2, the front mounting portion 15A is bolted laterally to the bracket 26, while the front mounting portion 15B is bolted vertically to the bracket 27. However, this is not limiting. For example, both front mounting portions 15A and 15B may be bolted vertically to the bracket, or both front mounting portions 15A and 15B may be bolted horizontally to the bracket. For example, if both front mounting portions 15A and 15B are configured to be bolted vertically to the bracket, in other words, if all four points are configured to be bolted vertically, the ease of assembly of the steering gearbox 10' can be improved.

In the above embodiments, the left suspension member 40, 60 and the right suspension member 50, 70 are connected via the steering gearbox 10 and the brace 30. However, this is not limited to this. In addition to the steering gearbox 10 and the brace 30, the left suspension member 40, 60 and the right suspension member 50, 70 may also be connected using, for example, a lightweight skeletal member extending in the same direction as the beams 31, 32 of the brace 30.

As such, the above-described embodiments are merely illustrative in all respects and should not be interpreted as limiting. Furthermore, all modifications and variations that fall within the scope of equivalence of the claims are within the scope of the present invention.

The present invention allows for significant weight and cost reductions while maintaining the functionality required of a suspension, making it extremely useful when applied to suspension structures equipped with a suspension member that supports a lower arm in a swingable manner.

10, 10' Steering gear box (framework member)
15 Front mounting portion 16 Rear mounting portion 17 Torque rod mounting portion 20 Stabilizer 26 Bracket (support member)
27 Bracket (support member)
30 Brace (framework member)
40, 40' Left side suspension member 50, 50' Right side suspension member 60, 60' Left side suspension member 70, 70' Right side suspension member 81 Left side lower arm 83 Right side lower arm 85 Torque rod 90 Front side member (vehicle body)

Claims (4)

A suspension structure including a suspension member and a steering gear box for steering wheels,
the suspension members include left and right suspension members spaced apart in a vehicle width direction, attached to the vehicle body at both ends in the vehicle width direction, and supporting the left and right lower arms, respectively, so as to be able to swing freely;
the left suspension member and the right suspension member are connected via the steering gear box extending in the vehicle width direction,
The vehicle further includes stabilizers supported by the left and right suspension members via support members, the stabilizers being located forward of the steering gear box in the vehicle longitudinal direction,
the steering gear box has a pair of left and right mounting portions on the front and rear sides in the vehicle longitudinal direction, the rear mounting portions being directly fastened to the left and right suspension members in the vertical direction with bolts, and the front mounting portions being attached to the left and right suspension members via the support members,
A suspension structure characterized in that the front mounting portion is configured to be bolted to the support member in the vertical or horizontal direction . 2. The suspension structure according to claim 1,
A suspension structure characterized in that braces for supporting an undercover that covers the underfloor of the vehicle are attached to the left and right suspension members from below. In the suspension structure according to claim 2,
A torque rod mounting portion for mounting a torque rod connected to an engine is formed in the center of the steering gear box in the vehicle width direction,
A suspension structure characterized in that the torque rod is sandwiched between the torque rod mounting portion and the brace from above and below. 2. The suspension structure according to claim 1,
A suspension structure characterized in that the left and right suspension members are constructed as solid members made of aluminum die-cast.