Measuring and testing – Instrument proving or calibrating – Displacement – motion – distance – or position
Reexamination Certificate
2002-07-22
2004-10-12
Noland, Thomas P. (Department: 2856)
Measuring and testing
Instrument proving or calibrating
Displacement, motion, distance, or position
C073S001750, C074S478000, C702S095000, C702S104000, C324S202000
Reexamination Certificate
active
06802202
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. 2001-227941 filed on Jul. 27, 2001 and Japanese Patent Application No. 2001-230464 filed on Jul. 30, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an accelerator pedal apparatus having an accelerator pedal position sensor for measuring an operational position of an accelerator pedal and also relates to a method for adjusting an output value of the accelerator pedal position sensor.
2. Description of Related Art
Recently, an accelerator pedal apparatus installed in a vehicle often includes an accelerator pedal position sensor, which is operated with an accelerator pedal and measures an operational position of the accelerator pedal. That is, the accelerator pedal position sensor generates an output (electrical signal) that corresponds to the operational position of the accelerator pedal. A throttle side of an engine (power unit), which controls power of the engine, includes a drive device, such as a motor, for driving a throttle valve of the engine. The drive device of the throttle valve is driven based on an output value of the accelerator pedal position sensor. Specifically, preset output values, which correspond to a fully closed position (i.e., operational position of the accelerator pedal before application of pressing force to the accelerator pedal) to a fully closed position (predetermined operational position of the accelerator pedal achieved after moving the accelerator pedal from the fully closed position), are generated from the accelerator pedal position sensor.
However, in the previously proposed accelerator pedal apparatus, it sometimes happens that the operational position of the accelerator pedal is deviated from the output value of the accelerator pedal position sensor due to a variation in attachment of the accelerator pedal position sensor relative to the accelerator pedal. That is, when the accelerator pedal is positioned to a predetermined operational position (such as the fully opened position or the fully closed position), the accelerator pedal position sensor does not output a preset output value assigned to the predetermined operational position.
Furthermore, the operational positions of the accelerator pedal can include an operational position located outside a normally used operational range between the fully closed position and the fully opened position. One example of such an operational position located outside the normally used operational range is known as a kickdown position. The accelerator pedal is pressed from the fully closed position to the fully opened position and is then further pressed to the kickdown position. The accelerator pedal is position to the kickdown position when the power of the engine needs to be increased from the power achieved at the fully opened position of the accelerator pedal. Specifically, when the accelerator pedal position sensor outputs an output value indicating the kickdown position, a gear ratio of a transmission is changed to increase the power of the engine.
Thus, a pedal pressing force control means is provided to allow the operator to note that the accelerator pedal is reached the kickdown position by providing a notable change, which can be noted by the operator, in the pedal pressing force when the accelerator pedal reaches the kickdown position. A preset output value, which corresponds to the notable change in the pedal pressing force, is outputted from the accelerator pedal position sensor. However, due to a fact that the pedal pressing force control means is provided separately from the accelerator pedal, the notable change in the pedal pressing force sometimes deviates from the preset output value that should be outputted from the accelerator pedal position sensor when the pedal pressing force control means generates the notable change in the pedal pressing force. This illustrates the difficulty of outputting the preset output value, which corresponds to the predetermined operational position of the accelerator pedal.
Even in the case where the accelerator pedal position sensor detects one of the fully closed position, the fully opened position and the kickdown position as the predetermined operational position of the accelerator pedal, when a notable change in the pedal pressing force made at the predetermined operational position does not match with sensor information (signal), which indicates the predetermined operational position, the operator cannot properly notice that the accelerator pedal is placed at the predetermined operational position, resulting in a mismatch between the notification of the operator and the output of the engine, which is driven based on the sensor information.
Apart from the above disadvantage,
FIGS. 8A and 8B
show a previously proposed accelerator pedal apparatus
100
. The accelerator pedal apparatus
100
includes an accelerator pedal
102
, which is rotated about a rotational shaft
101
by pedal pressing force applied to the accelerator pedal
102
. The accelerator pedal apparatus
100
also includes a fully opened position stop member
103
. For example, with reference to
FIG. 8B
, when the accelerator pedal
102
is pressed, a pressing force (F
11
in
FIG. 8B
) is applied to one end of the accelerator pedal
102
, so that the accelerator pedal
102
is positioned to a fully opened position. When the accelerator pedal
102
reaches the fully opened position, the fully opened position stop member
103
engages with a corresponding portion of the accelerator pedal
102
and thus prevents further rotation of the accelerator pedal
102
. In the previously proposed accelerator apparatus
100
, the fully opened position stop member
103
is provided only at one position. The accelerator pedal apparatus
100
also includes a fully closed position stop member
104
. With reference to
FIG. 8A
, when the pressing force F
11
applied to the one end of the accelerator pedal
102
is released, a return force (F
110
in FIG.
8
A) is applied to the accelerator pedal
102
to return the accelerator pedal
102
to the fully closed position. Similar to the fully opened position stop member
103
, when the accelerator pedal
102
reaches the fully closed position, the fully closed position stop member
104
engages with a corresponding portion of the accelerator pedal
102
and thus prevents further rotation of the accelerator pedal
102
. The fully closed position stop member
103
is provided only at one position.
In the case where the fully opened position stop member
103
is provided only at the one position like in the previously proposed accelerator pedal apparatus
100
, when the accelerator pedal
102
is rotated to the fully opened position to cause the engagement of the corresponding portion of the accelerator pedal
102
with the fully opened position stop member
103
, a load F
12
is applied to the fully opened position stop member
103
, as shown in FIG.
8
B. Then, a portion of the fully opened position stop member
103
, which is engaged with the accelerator pedal
102
, acts as a fulcrum point. Thus, when the accelerator pedal
102
is further rotated about the rotational shaft
101
, the accelerator pedal
102
is pivoted on the portion of the fully opened position stop member
103
acting as the fulcrum point, and thus a relatively large load F
13
is applied to the rotational shaft
101
in a direction opposite to that of the load F
12
. That is, the load F
13
applied to the rotational shaft
101
is proportional to the pressing force F
11
of the operator. Thus, when the operator applies the larger amount of pressing force to the accelerator pedal
102
, the larger amount of the load F
13
is applied to the rotational shaft
101
. Also, in the case of releasing the accelerator pedal
102
, when the operator abruptly releases the accelerator pedal
102
, the accelerator pedal
102
abruptly hits the fully closed position stop member
104
to generate a load F
120
. Thus, a re
Kato Yasunari
Makino Masahiro
Denso Corporation
Nixon & Vanderhye PC
Noland Thomas P.
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