Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
2000-10-05
2002-04-30
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C180S445000
Reexamination Certificate
active
06381527
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to controller units for rear-wheel steering apparatus and, more particularly, to an electronic controller module or unit which achieves improved behavior of rear-wheel steering apparatus in vehicles, typically four-wheel steering (4WS) automotive vehicles, that are designed to steer rear wheels in association with steering of front wheels.
2. Description of the Related Art
Hitherto, four-wheel steering vehicles have been known and used popularly. The four-wheel steering vehicles are arranged to change the steering direction of the rear wheels simultaneously with steering of the front wheels in response to a manual steering maneuver of the steering wheel by a human vehicle operator or driver. During high-speed travel of the vehicle, for example, the four-wheel steering allows the vehicle to make lane changes with sufficient stability by steering the rear wheels in the same direction as the front wheels. Also, when the vehicle is traveling at low speed in a narrow space, the four-wheel steering allows the vehicle to make a small left or right turn by steering the rear wheels in an opposite direction to the front wheels. Steering direction of the rear wheels relative to a steering direction of the front wheels depends on an intended purpose of the vehicle travel (i.e., traveling speed of the vehicle, steering angle of the front wheels, etc.). Generally, every four-wheel steering vehicle includes, in addition to a front-wheel steering apparatus, a separate rear-wheel steering apparatus that steers the rear wheels, in response to a steering maneuver of the steering wheel by the vehicle operator, in association with steering of the front wheels. The rear-wheel steering apparatus constitutes an essential part of the four-wheel steering vehicles.
Basic construction and operation of the conventionally-known rear-wheel steering apparatus is outlined as follows. Two rear wheels, located on both sides of a rear body portion of the four-wheel vehicle, are connected, via knuckle arms (also called steering arms) or other connecting mechanism, to opposite ends of a single rear-wheel steering rod disposed in a widthwise direction of the vehicle. There are also provided steering-rod actuating mechanisms for moving the rear-wheel steering rod axially in a leftward or rightward direction and a drive operatively connected with the steering-rod actuating mechanisms. Namely, the rear wheels are operatively connected to the drive via the rear-wheel steering rod. When the rear-wheel steering rod is at a central neutral position with its axial midpoint substantially coinciding with the longitudinal centerline of the vehicle, the rear wheels are directed straight ahead in parallel to the longitudinal centerline of the vehicle. As the rear-wheel steering rod is moved axially leftward or rightward by the drive via the steering-rod actuating mechanisms, the two rear wheels are caused to pivot in a direction opposite to the axial movement direction of the rear-wheel steering rod.
The following paragraphs describe in greater detail an example of the conventional rear-wheel steering apparatus for accurate understanding of the construction and operation of the rear-wheel steering apparatus, with reference to the accompanying drawings. Specifically,
FIGS. 16
to
22
schematically show principal parts of the rear-wheel steering apparatus proposed earlier by the assignee of the present application. More specifically,
FIGS. 16
to
22
outline the rear-wheel steering apparatus disclosed in Japanese Patent Application No. HEI-11-169609, which was filed on Jun. 16, 1999 and then laid open as Japanese Patent Laid-open Publication No. 2000-79881. The present invention is directed to providing solutions to the inconveniences that would be encountered by the earlier-disclosed rear-wheel steering apparatus. The inconveniences of the earlier-disclosed rear-wheel steering apparatus will be explained below with reference
FIGS. 16
to
22
.
More specifically,
FIG. 16
is an exploded perspective view of the earlier-disclosed rear-wheel steering apparatus. The rear-wheel steering apparatus, generally represented at reference numeral
400
, includes a screw shaft
421
extending parallel to the above-mentioned rear-wheel steering rod
440
. Threaded direction of the screw shaft
421
is reversed at its axial midpoint; that is, the screw shaft
421
includes left-handed and right-handed thread sections
421
L and
421
R. The screw shaft
421
, having such left-handed and right-handed thread sections
421
L and
421
R, is driven by an electric motor
411
, by way of a speed reduction mechanism
417
, to rotate in the clockwise or counterclockwise direction. Left and right slide blocks
420
L and
420
R are mounted on the screw shaft
421
; more specifically, lower portions of these left and right slide blocks
420
L and
420
R mesh with the screw shaft
421
by female-thread/male-thread engagement. By the clockwise or counterclockwise rotational movement and threaded engagement with the left and right slide blocks
420
L and
420
R, the screw shaft
421
functions as a drive shaft for moving the left and right slide blocks
420
L and
420
R in parallel to the shaft
421
, as will be later described more fully with reference to
FIGS. 18 and 19
. Center piece
441
is fixedly mounted at the axial center of the rear-wheel steering rod
440
, and the left and right slide blocks
420
L and
420
R are positioned adjacent opposite ends of the center piece
441
on the steering rod
440
. The rear-wheel steering rod
440
are threaded through holes formed in respective upper portions of the left and right slide blocks
420
L and
420
R.
Clutch mechanisms
430
L and
430
R are attached to the left and right slide blocks
420
L and
420
R, respectively. Turning on the clutch mechanisms
430
L and
430
R causes the left and right slide blocks
420
L and
420
R to be operatively connected to the rear-wheel steering rod
440
that is threaded through the holes in the slide blocks
420
L and
420
R with the clutch mechanisms
430
L and
430
R interposed therebetween. Turning off the clutch mechanisms
430
L and
430
R, on the other hand, cancels the operative connection between the left and right slide blocks
420
L and
420
R and the rear-wheel steering rod
440
. In this prior art rear-wheel steering apparatus, however, only either one of the slide blocks
420
L and
420
R is actually connected to the rear-wheel steering rod
440
with the other slide block
420
R or
420
L left disconnected from the steering rod
440
; note that both of the left and right slide blocks
420
L and
420
R are never simultaneously connected to the rear-wheel steering rod
440
.
The above-mentioned clutch mechanisms
430
L and
430
R each have an actuating lever
424
L or
424
R projecting outwardly from a clutch ring
432
L or
432
R in a direction substantially perpendicular to the axis of the rear-wheel steering rod
440
. The actuating levers
424
L and
424
R are movable within and along a guide groove
431
as shown in
FIG. 17
that is formed in a casing (not shown). Namely, horizontal groove portions of the guide groove
431
allows the actuating levers
424
L and
424
R to move within a predetermined horizontal range parallel to the screw shaft
421
; thus, the horizontal movement of the actuating levers
424
L and
424
R parallel to the screw shaft
421
is limited by the length of the horizontal groove portions so that the levers
424
L and
424
R are horizontally movable only within the predetermined range along the screw shaft
421
. Further, as clearly seen from
FIG. 17
, the actuating levers
424
L and
424
R can be moved, by activation of electrically-operated actuators
425
L and
425
R, along vertical groove portions of the guide groove
431
only when the left and right slide blocks
420
L and
420
R are at respective central or neutral positions corresponding to the axial midpoint portion of the screw shaft
421
. In
FIG. 17
, both of the le
Furumi Hiroshi
Shirakawa Kunio
Cuchlinski Jr. William A.
Donnelly Arthur D.
Honda Giken Kogyo Kabushiki Kaisha
Merchant & Gould P.C.
LandOfFree
Control unit for rear-wheel steering apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control unit for rear-wheel steering apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control unit for rear-wheel steering apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2885383