Land vehicles – Wheeled – Running gear
Reexamination Certificate
2000-09-21
2002-06-11
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Running gear
C280S781000
Reexamination Certificate
active
06402172
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an automotive suspension frame construction for supporting suspension lower arms, an engine mount member, and the like.
Generally, vehicle body constructions of a motor vehicle are broadly divided into a framed construction used for trucks etc. and a frame-less construction used for passenger cars etc. For the frame-less construction, an attempt to increase the torsional rigidity is made by incorporating side members and cross members as a part of a body instead of using a frame. Chassis parts are installed directly to the body, but on some types of vehicles, they are assembled to the body after being installed to a partial frame or a sub-frame.
This sub-frame is usually referred to as a suspension frame because the suspension lower arms are installed to both sides thereof. Hereafter, the sub-frame etc. are generally referred to as a suspension frame.
The suspension frame is fitted with the suspension lower arms, a stabilizer, and the like, and thereafter is assembled to a vehicle body. The suspension frame is generally formed by an upper plate, a lower plate, and lower arm mounting brackets, as its basic construction.
FIGS. 8
to
10
show a construction of a conventional suspension frame (Japanese Patent Provisional Publication No. 7-179180).
A suspension frame
100
is supported by a pair of side members
101
,
101
on both sides, and suspension lower arms
102
,
102
are installed on both sides of the suspension frame
100
. A center member
104
is installed between the suspension frame
100
and a cross member
103
provided in the front, and an engine
105
is assembled onto the center member
104
.
The suspension frame
100
is usually disposed at the lower part of an engine room partitioned by a dash panel
106
, and various kinds of equipment etc. are assembled to the suspension frame
100
. The dash panel
106
is fitted with a steering knuckle
107
by means of brackets
108
.
As shown in
FIGS. 11
to
13
, the suspension frame
100
is formed by joining an upper plate
109
to a lower plate
110
by welding or the like. These plates
109
and
110
are usually formed by pressing a steel sheet or the like. On both sides, right and left, of the suspension frame
100
, vehicle body mounting portions h, i and j for mounting the suspension frame
100
to a vehicle body are provided. On both sides in the vehicle width direction of the suspension frame
100
, a pair of suspension lower arm mounting portions
100
a
,
100
b
are provided. At this suspension lower arm mounting portion
100
a
on the front side of the vehicle body, a lower arm mounting bracket
111
is provided in a cantilever manner.
The lower arm mounting bracket
111
is formed into a substantially square box shape with one side face being open by pressing or the like, and on opposed wall faces
111
a
and
111
b
are provided pivotally supporting portions
112
,
112
for the suspension arm
102
,
102
. Since the lower arm mounting bracket
111
is supported in a cantilever manner on the outside of the vehicle body mounting portions h, i and j of the suspension frame
100
, this configuration provides a construction that suffers disadvantages of low rigidity, decreased steering stability, and high vibrating noise.
As shown in
FIG. 13
, the mounting portion of the lower arm mounting bracket
111
is joined by partially lapping a distal end portion
109
a
of the upper plate
109
on the top face of the lower arm mounting bracket
111
. Also, the distal end of the lower plate
110
is butted against the wall face of the lower arm mounting bracket
111
, so that a reinforcement
113
is installed between the upper plate
109
and the lower plate
110
to reinforce the lower arm mounting bracket
111
. Further, a flange portion
114
is provided along the opening end portion of the lower arm mounting bracket
111
to increase the rigidity of the lower arm mounting bracket
111
.
The suspension frame
100
is subjected to the severest condition when a longitudinal load is applied (on an actual vehicle, when a brake is applied, when a wheel drops down into a pothole, or on other occasions).
The deformation mode of the suspension frame
100
at the time of braking load application is, as shown in
FIG. 14
, a mode in which the mounting portions of the lower arm mounting brackets
111
are opened to the outside while being twisted, and the central portion of the suspension frame
100
is lowered.
The central portion of the suspension frame
100
is lowered in the same manner when a load is applied from an engine mount member at the time of sudden start.
Conventionally, therefore, as shown in
FIGS. 15 and 16
, a reinforcement
115
is disposed between the upper plate
109
and the lower plate
110
to reinforce the central portion of the suspension frame
100
. The upper plate
109
and the lower plate
110
are lapped on one another on the front side and form a closed curved surface on the rear side in the longitudinal direction of the vehicle body, and on the front side, the reinforcement
115
is held between the upper plate
109
and the lower plate
110
, and the rear end portion of the reinforcement
115
is welded to the lower face of the closed curved surface on the rear side. Thus, engine mount member mounting portions k are formed at portions where the upper plate
109
, the lower plate
110
, and the reinforcement
115
are lapped on one another.
However, although the engine mount member mounting portions k are formed by lapping the upper plate
109
, the lower plate
110
, and the reinforcement
115
on one another, they are lowered by a load applied from the engine mount member at the time of sudden start, so that the rigidity is insufficient. Also, since the primary natural frequency of the suspension frame
100
resonates with the vehicle body, a mass damper is needed.
OBJECT AND SUMMARY OF THE INVENTION
The present invention has been made to solve the above problems, and accordingly an object thereof is to provide an automotive suspension frame construction that can increase the rigidity when a brake is applied or when an engine mount load is applied.
To achieve the above object, the present invention provides an automotive suspension frame construction in which an upper plate and a lower plate are joined to one another to form a suspension frame, suspension lower arm support portions are provided on each side, right and left, of the suspension frame, and an engine mount member mounting portion is provided at a substantially central portion of the suspension frame, wherein the engine mount member mounting portion of the suspension frame is formed into a closed cross section and a reinforcement is disposed in the closed cross section, cylindrical elements through which engine mount member fastening members are inserted are caused to penetrate the upper plate, reinforcement, and lower plate at positions corresponding to the engine mount member mounting portion of the suspension frame, and the upper plate, reinforcement, and lower plate are welded to the cylindrical elements.
Also, in the present invention, the reinforcement is disposed slantwise in the longitudinal direction of a vehicle body.
Further, in the present invention, a joint portion of the reinforcement and the cylindrical elements is formed into a horizontal shape.
Still further, in the present invention, the front end portion of at least the central portion of the upper plate is lowered to be joined to the front end portion of the central portion of the lower plate, and the rear end portion of at least the central portion of the lower plate is raised to be joined to the rear end portion of the central portion of the upper plate, whereby a closed cross-sectional construction is formed at the central portion of the suspension frame, and a front end flange portion of the reinforcement is joined to the front lower face of the lower plate and the rear end thereof is joined to the rear upper end of the lower plate by being butted against it.
Further, the
Alston & Bird LLP
Fleming Faye M.
Johnson Brian L.
Suzuki Motor Corporation
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