Lower arm mounting structure of vehicle suspension

A lower arm mounting structure of a vehicle suspension includes a first mount mounted to a wheel of a vehicle, a second mount mounted to a sub frame side member at one side of the sub frame side member, and a third mount mounted to the sub frame side member at the other side of the sub frame side member. The third mount is fastened to the sub frame side member at two points spaced apart from each other in a longitudinal direction of the sub frame side member by bolts. The lower arm mounting structure prevents the mounts from being displaced during the cornering of the vehicle. Accordingly, it is possible to reduce or eliminate the phenomenon that the front part of the vehicle is inclined, and to achieve an enhancement in vehicle handling performance.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2005-0103871 filed in the Korean Intellectual Property Office on Nov. 1, 2005, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lower arm mounting structure of a vehicle suspension, and, more particularly, to a lower arm mounting structure which provides two-point support for a lower arm of the vehicle suspension mounted to a sub frame side member.

2. Description of the Related Art

In a conventional lower arm mounting structure, a lower arm of a suspension may include a first rod which is connected to a wheel of a vehicle, a second rod which extends from the first rod in one direction, and is connected to one side of a sub frame side member, and a third rod108which extends from the first rod in a direction opposite to the second rod, and is connected to the other side of the sub frame side member.

A first mount may be formed at a terminal end of the first rod to mount the first rod104to the wheel. A second mount may be formed at a terminal end of the second rod to mount the second rod to one side of the sub frame side member. A third mount may be formed at a terminal end of the third rod to mount the third rod to the other side of the sub frame side member.

A horizontal through hole through the third mount may be provided at the terminal end of the third rod. A rubber bush is fitted through the hole and thus, the third rod may be fastened to a mounting bracket formed at the other side of the sub frame side member by a bolt which extends through the rubber bush.

In a conventional lower arm, however, slight displacement occurs at the third mount when a lateral reaction force is applied to the third mount during cornering of the vehicle because the rubber bush fitted in the third mount is slightly elastically deformed due to the lateral reaction force. For this reason, excessive displacement occurs at the first mount, thereby causing the body of the vehicle to be inclined.

A sub frame is arranged beneath an engine room of the vehicle. The sub frame supports an engine and a transmission arranged at the top of the sub frame. The sub frame is also connected to the lower arm of the suspension at one side of the sub frame to secure a desired structural rigidity of the vehicle and to achieve an effective load distribution.

The load distribution path established during sharp cornering of the vehicle may be analyzed as follows. Primarily, a lateral reaction force caused by a reaction to turning of the vehicle is transmitted to the lower arm of the sub frame. Secondarily, the transmitted lateral reaction force is exhibited in the form of a torsion generated at openings in a passenger room of the vehicle. Thirdly, the residual lateral reaction force is exhibited in the form of a rear torsion generated at a rear floor of the passenger room, and thus, vibration.

Thus, the rubber bush used to mount the second mount to the sub frame is elastically deformed during cornering of the vehicle, so that the second mount is displaced relative to the sub frame. The displacement of the second mount causes the third mount to be displaced. As a result, an inclination of the vehicle body occurs.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a lower arm mounting structure of a suspension in a vehicle in which a mount of a lower arm has a plate structure to be fastened to a sub frame side member at two points spaced apart from each other in the longitudinal direction of the side member by bolts, thereby being capable of minimizing displacement of the mount, and thus, reducing or eliminating the phenomenon that the front part of the vehicle is inclined, and achieving an enhancement in vehicle handling performance.

In accordance with an exemplary embodiment of the present invention, a lower arm mounting structure of a vehicle suspension comprises a first mount which is mounted to a wheel of a vehicle, a second mount which is mounted to a sub frame side member at one side of the sub frame side member, and a third mount which is mounted to the sub frame side member at the other side of the sub frame side member. The third mount may be fastened to the sub frame side member at two points spaced apart from each other in a longitudinal direction of the sub frame side member by bolts.

The first mount may include a bolt fastening hole which allows the first mount to be fastened to the wheel by a bolt.

The second mount may include a vertical through hole formed through the second mount, and a bush fitted in the through hole. The second mount may be fastened to the sub frame side member by a bolt which extends through the bush.

The third mount may include a mounting plate integrally formed at a terminal end of a lower arm of the vehicle suspension such that the mounting plate extends in the longitudinal direction of the sub frame side member, and a bolt fastener formed at the other side of the sub frame side member, to fasten the mounting plate to the sub frame side member at the two points using the bolts.

The mounting plate may extend from the terminal end of the lower arm by a certain length in opposite directions perpendicular to a longitudinal direction of the lower arm. The mounting plate may include bolt fastening holes formed through opposite ends of the mounting plate, respectively. The bolts may be fastened to the bolt fastening holes, respectively.

The bolt fastener may have the form of a recess to receive the mounting plate. The bolt fastener may include bolt fastening holes formed in an inner surface of the bolt fastener at opposite sides of the bolt fastener, respectively, and a rigidity reinforcing rib formed at a central portion of the inner surface of the bolt fastener.

The rigidity reinforcing rib may have a stepped structure, and may be upwardly protruded from the sub frame side member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, exemplary embodiments of the present invention will be described in detail with reference to the annexed drawings.

The lower arm, which is designated by reference numeral10inFIG. 1, includes a first rod12which is connected to a wheel of a vehicle, a second rod14which extends from the first rod12in one direction, and is connected to a front portion of a sub frame side member20, and a third rod16which extends from the first rod12in a direction opposite to the second rod14, and is connected to a rear portion of the sub frame side member20.

The sub frame30includes a front member32which extends in a lateral direction of a vehicle body at a front side of the vehicle body. The side member20is also included in the sub frame30. Although not shown, the sub frame30includes another side frame20. The two side members20extend in a longitudinal direction of the vehicle body, and are connected to opposite ends of the front member32, respectively. The sub frame further30further includes a rear member32which extends in the lateral direction of the vehicle body, and is connected to rear portions of the side members20at opposite ends of the rear member32, respectively. For simplicity of description, the following description will be given only in conjunction with one side member20to which the lower arm10is mounted.

The lower arm10is mounted to the side member20, and is connected to the wheel of the vehicle.

A first mount40is formed at a terminal end of the first rod12to mount the first rod12to the wheel. A second mount50is formed at a terminal end of the second rod14to mount the second rod14to the front portion of the sub frame side member20. A third mount60is formed at a terminal end of the third rod16to mount the third rod16to the rear portion of the sub frame side member20.

A vertical bolt fastening hole42is formed through the first mount40, in order to allow the first mount40, and thus, the first rod12, to be fastened to the wheel by a bolt.

A vertical through hole52is formed through the second mount50provided at the terminal end of the second rod14. A rubber bush54is fitted in the through hole52. The second mount50, and thus, the second rod14, is fastened to a mounting bracket56formed at the front portion of the sub frame side member20by a bolt which extends through the rubber bush54.

As shown inFIG. 2, the third mount60includes a mounting plate62formed at the terminal end of the third rod16to extend in the longitudinal direction of the side member20, and a bolt fastener64formed at the side member20to extend in the longitudinal direction of the side member20, in order to fasten the mounting plate20to the side member20using a bolt.

The mounting plate62extends from the terminal end of the third rod16by a certain length in opposite directions perpendicular to a longitudinal direction of the third rod16. Bolt fastening holes66are formed through opposite ends of the mounting plate62, respectively. Bolts70may extend through the bolt fastening holes66, respectively. The mounting plate62is integrated with the terminal end of the third rod16.

The bolt fastener64has the form of a recess so that the mounting plate62is received in the bolt fastener64. Bolt fastening holes68are formed in an inner surface of the bolt fastener64at opposite sides of the bolt fastener64, respectively. A rigidity reinforcing rib72is formed at a central portion of the inner surface of the bolt fastener64, in order to locally increase the rigidity of the bolt fastener64.

The rigidity reinforcing rib72has a stepped structure, and is upwardly protruded from the side member20.

The lower arm mounting structure having the above-described configuration according to the present invention can minimize elastic deformation of the rubber bushes caused by a lateral reaction force generated during cornering of the vehicle because the third mount60is fastened to the sub frame30at two points spaced apart from each other in a longitudinal direction of the sub frame30by the bolts70. Accordingly, it is possible to prevent the lower arm mounting structure from being displaced during the cornering of the vehicle, and thus, to reduce or eliminate the phenomenon that the front part of the vehicle is inclined.

As apparent from the above description, the lower arm mounting structure according to embodiments of the present invention in which the mount of the lower arm is fastened to the sub frame side member at two points spaced apart from each other in the longitudinal direction of the side member by bolts, to minimize displacement of the mount. Accordingly, it is possible to reduce or eliminate the phenomenon that the front part of the vehicle is inclined, and to achieve an enhancement in vehicle handling performance.