Land vehicles – Wheeled – Running gear
Reexamination Certificate
1999-03-18
2002-09-03
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Running gear
C280S777000, C280S780000, C074S493000
Reexamination Certificate
active
06443491
ABSTRACT:
This application claims the benefit of Japanese Application No. 10-71713 which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for rockably supporting a steering column for a tilt-type steering apparatus. The device for rockably supporting a steering column for a tilt-type steering apparatus is adapted to support the front part of the steering column to allow rock thereof to freely adjust the height of a steering wheel. The present invention further relates to a device for rockably supporting a steering column for a tilt-type steering apparatus that allows the steering column to be displaced forward while absorbing energy generated upon a secondary collision (collision of a driver with a steering wheel).
2. Related Background Art
To adjust the height of the steering wheel of a car to meet the physical constitution or a driving posture of the driver, a height adjustment apparatus of a steering wheel called a tilt-type steering apparatus is conventionally widely used. A support device for rockably supporting the front part of the steering column to allow rocking movement and adjust tilt of the steering column is incorporated in such tilt-type steering apparatus.
FIGS. 9
to
11
show an example of the tilt-type steering apparatus incorporating such support device of the steering column disclosed in Japanese Utility Model Application Laid-Open No. 4-114872. In these figures, a fixed or stationary bracket
1
is supported and fixed to the car body at the lower face of the dashboard. This fixed bracket
1
has a pair of vertical walls
2
that are in parallel to each other, and a pair of elongated holes
3
that are respectively formed in a vertical direction (up-and-down direction in
FIG. 9
) at positions of the paired vertical walls
2
to be aligned with each other.
An up and down movable bracket
5
is fixed to an intermediate portion of a steering column
4
through which a steering shaft
10
is inserted, and this movable bracket
5
is sandwiched between the paired vertical walls
2
. Both ends of a movable rod
6
that passes through the movable bracket
5
in the lateral direction (direction perpendicular to the sheet in
FIG. 9
) are projected from the outer sides of the paired vertical walls
2
through the paired elongated holes
3
. A tilt lever
7
is supported at one of these ends. This tilt lever
7
is operable to engage the fixed bracket
1
with the movable bracket
5
or release such engagement.
When the tilt lever
7
is in the state shown in
FIG. 9
, the inner sides of the vertical walls
2
of the fixed bracket
1
are urged upon the outer side of the movable bracket
5
by a nut (not shown) that is fixed to the center of rotation of this tilt lever
7
and threadably engaged with the end of the movable rod
6
. Thus, the movable bracket
5
is fixed to the fixed bracket
1
. At the same time, an edge of a stopper
8
formed at the base end of the tilt lever
7
and a stretching wall
9
formed on the fixed bracket
1
are brought into abutment.
When the tilt lever
7
is rotationally moved from the state shown in
FIG. 9
in the clockwise direction in the same figure, the edge of the stopper
8
and the stretching wall
9
are separated from each other and the urged state mentioned above is released. Then, the movable bracket
5
is freely movable upward or downward.
A support bracket
11
is provided on the outer periphery of the front-end portion of the steering column
4
(the left end part in FIG.
9
). This support bracket
11
is integrally formed of a metallic plate having elasticity such as a steel platemade by press-forming. An upper edge portion of this support bracket
11
constitutes a mounting portion
12
that is bent at a right angle backward (to the right in
FIGS. 9 and 10
) to be attached to the car body. Circular holes
13
,
13
each for-receiving a mounting bolt are formed at both ends of this mounting portion
12
. A circular hole
15
for receiving the steering column
4
is formed at the center of a support portion that is extended downward from the front edge of the mounting portion
12
at a right angle. Plural support flaps
19
(four in the illustrated example) are formed at intervals on the periphery of the circular hole
15
with cut-away portions
17
each formed between the edges of adjacent support flaps
19
in the circumferential direction. Arched walls
16
are formed on the inner edges of these support flaps
19
to be bent at a right angle backward from the inner edges of the support flaps
19
. These arched walls
16
jointly constitute a cylindrical support portion
18
. The arched walls
16
are formed such that the inner diameter of the cylindrical support portion
18
in a free state is slightly smaller than the outer diameter of the front part of the steering column
4
.
Into the cylindrical support portion
18
of the support bracket
11
constituted as described above, the front-end portion of the steering column
4
is inserted, elastically deforming outward in the radial direction the arched walls
16
constituting this cylindrical support portion
18
. Then, after the insertion, the front-end portion of the steering column
4
is elastically supported on the inner side of this cylindrical support portion
18
. In this state, the front-end portion of the steering column
4
is elastically urged over the entire circumference thereof (except the cut-away portions
17
mentioned above) by the cylindrical support portion
18
constituted by the arched walls
16
. Further, the support bracket
11
is fixed to the car body by bolts that pass through the respective circular holes
13
,
13
of the mounting portion
12
from below.
In the case of a tilt-type steering apparatus constituted as described above, when the steering column
4
is rocked upon the height adjustment of the steering wheel, the arched walls
16
constituting the cylindrical support portion
18
are elastically deformed. At the same time, when an inner peripheral surface of a part of the arched wall
16
slides on the outer peripheral surface of the steering column
4
, smooth rocking of the steering column
4
is allowed. In the state in which the front-end portion of the steering column
4
is thrust into the cylindrical support portion
18
, this cylindrical support portion
18
elastically suppresses the front-end portion of the steering column
4
substantially over the entire periphery thereof.
The conventional tilt-type steering apparatus constituted as described above has significant drawbacks. For example, in the conventional structure, it is impossible for the support bracket
11
to stabilize a collapse load required for displacing the steering column
4
forward in a secondary collision, as described above. More specifically, in the case of the conventional structure, the arched walls
16
are formed as being bent at right angles backward from the inner peripheries of the support flaps
19
. As a result, when the front-end portion of the steering column
4
is displaced forward in the secondary collision, the leading edge of all or a part of the arched walls
16
(the right edge in
FIGS. 9 and 10
) possibly bites into the outer peripheral surface of the steering column
4
. In this case, it is difficult for the steering column
4
to be displaced forward and the collapse load possibly becomes unstable. For this reason, in the conventional structure, the steering column
4
is formed by telescopically combining an outer column and an inner column to be contracted in the secondary collision. However, such contractible steering column costs more, compared with a single-column structure steering column.
When the front-end portion of the steering column
4
is inserted into the cylindrical support portion
18
from the rear side (the right side in
FIGS. 9 and 10
) of the support bracket
11
so that the front part of the steering column
4
is inserted into the cylindrical support portion
18
, the front edge of the steering column
4
and the leading e
Draper Deanna L.
Miles & Stockbridge P.C.
NSK Ltd.
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