Land vehicles – Wheeled – Running gear
Reexamination Certificate
1999-11-02
2001-11-06
Dickson, Paul N. (Department: 3618)
Land vehicles
Wheeled
Running gear
Reexamination Certificate
active
06311996
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a suspension arm used in a suspension mechanism mounted on a vehicle.
2. Related Art
Conventionally, in a suspension mechanism mounted on a vehicle, a suspension arm connected with an another connecting bar in a vibration preventing condition and forms a link mechanism has been used. This suspension arm is manufactured by or made of mainly a ferrous material and formed by a press working or a forging. Recently, for lightening the suspension arm, a light metallic materials such as an aluminium alloy and the like formed by the forging have been adopted.
By the way, the suspension arm can have various shapes corresponding to an attached location thereof to the vehicle. For example, an upper arm attached to an upper portion of the suspension mechanism and a lower arm attached to a lower portion of the suspension arm have bent shapes such as an arch shape, V-shape or U-shape. However, when these bent suspension are formed by forging the aluminium alloy, the suspension arm of hollow shape is hardly formed, which makes further lightening of the suspension arm difficult.
In addition, when the suspension is comprised of an arm member and a pair of bearing members attached to both ends of the arm member, if whole of the suspension arm including the bearings are formed by the forging, a bearing to bearing distance between the bearing members provided at the both ends of the arm member requiring an especially high dimensional accuracy, can not be maintained in high accuracy. As a result, various cutting working become necessary after the forging for maintaining the dimensional accuracy, which introduces increase of a working man-hour and a manufacturing cost.
SUMMARY OF THE INVENTION
The present invention is made in view of the above mentioned circumstances, and therefore intends to provide a suspension arm for the suspension mechanism which can avoid the increase of the working man-hour and the manufacturing cost, and also can further lighten the weight thereof.
For achieving the above purpose, in the invention recited in the claim
1
, a suspension arm is comprised of 1) an arm member formed into a pipe shape by extruding an aluminium alloy, and having at least a part thereof a bent portion, and 2) a pair of bearing members made of an aluminium alloy and joined to each of end portions of said arm member respectibely. The bent portion of said arm member is formed by bending said arm member after said pair of bearing members are joined to each end portion of said arm member.
According to this invention, the arm member which constitutes a main part of the suspension arm is manufactured by the light aluminium alloy and formed into a pipe shape of hollow constructions, so that an amount of the aluminium alloy is greatly decreased to lighten the suspension arm sufficiently, and a high rigidity is maintained. In addition, since this suspension arm is formed by the extrusion, only a small post working such as cut working and the like is required. Further, the bent portion of the suspension arm is formed after the paired bearing members are attached to the both ends of the suspension arm, in other words, the bearing members can be attached to the straight suspension arm, which makes the attach working of the bearing members to the arm member easy. Thus, this invention can avoid the increase of the working man-hour and the manufacturing cost, and can lighten the weight of the suspension arm sufficiently.
The arm member of this invention is formed into the pipe shape by extruding the aluminum alloy. The material of the aluminium alloy is not limitative, and the aluminium alloy of Al—Mg—Si system such as A6061T6 or 6NO1 and the like are preferably used, from a view point of strength and anti-corrosion character. As an extruding method of the arm member, a hot extruding method, which is a popular forming method of the aluminium alloy, is preferably used. As a pipe shape of the arm member, a cylindrical shape, rectangular shape or irregular hollow shape in which a plurality of independent, parallel hollow portions are formed, can be used.
The arm member of this invention has at least a part thereof, a bent portion bent into the arch shape. This bent portion can be formed over the arm member such as a semi-circle or quater circle, or can be locally formed at a central portion of the arm member such as U-shape or V-shape. This bent portion is formed by bending the arm member by a known pressing apparatus easily, after the bearing members are attached to the both end of the arm member. As a result, the bearing members can be attached to the straight arm member easily.
The bearing members of this invention is manufactured by the aluminium alloy, and can have various shape which is provided with a connecting portion to be connected to the arm member, or a cylindrical portion on which a vibration preventing member to be explained later is mounted. A material of the aluminium alloy which constitutes the bearing member is not limitative, and the aluminium alloy of Al—Mg—Si system such as A6063T6 and the like are preferably used, from viewpoint of the strength and the anti-corrosion character. The bearing member can be formed by the extruding, a die-casting or the forging.
As a join method for joining the bearing member of the aluminium alloy to the arm member of the aluminium alloy, one of the conventional, known join method such as a friction agitate joining, a frictionally abutted joining, a MIG welding and a laser welding can be used. Especially, in this invention, since the bearing members are joined to the straight arm member which has not been subjected to the bend working, the friction agitate joining or the frictionally abut joining in which a building is relatively easy and which can maintain the sufficient joining strength is preferably used. Here, “the friction agitate joining” is the joining method in which a rotating body which rotates between a pair of opposed members with contacting with them is moved, and surface portions of the both members a deforming resistance of which is reduced by a friction heat are agitated to join the both members. The “frictionally abut joining” is the joining method in which by a relative movement between the opposed members a friction heat is generated at the boundary surface, and a high temperature portion at the boundary surface is pressed and extruded to join the both members.
In the invention recited in the claim
2
, an intermediate bearing member is joined to an intermediate portion of the arm member. According to this invention, since the bearing member can be joined to the portion of the arm member other than the both end portions, the suspension arm which is connected the associating member of the suspension mechanism at more than three portions can be obtained. Here, plural intermediate bearing members can be attached to plural positions on the arm member.
In the invention recited in the claim
3
, the arm member has a flat surface formed at a part of an outer peripheral surface thereof in extruding and extending in the extruded direction. According to this invention, when the intermediate bearing member is joined to the arm member, the joined surface of the arm member is flat, not curved, at least in a cross-section perpendicular to the extruding direction, which can heighten the joining responsibility of the intermediate bearing member to the arm member. In addition, when the arm member is formed into the pipe shape which has an inner peripheral surface, due to formation of the flat surface at the part thereof, a modulus of section and a rigidity of the arm member can be increased, to thereby heighten the strength and durability of the arm member.
In the invention recited in the claims
4
to
6
, the both end portions of the arm member, or the both bearing member at the both ends of the arm member are connected with each other by a connecting bar. According to this invention, a positional error occurred between the both ends of the arm member in bending the arm member can
Kato Rentaro
Kawata Naoyuki
Nishikawa Naoki
Tochigi Masaharu
Dickson Paul N.
Fleming Faye M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tokai Rubber Industries Ltd.
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