Machine element or mechanism – Control lever and linkage systems – Foot operated
Reexamination Certificate
2001-09-07
2003-07-15
Bucci, David A. (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Foot operated
Reexamination Certificate
active
06591712
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a pedal device having a damper for imparting an appropriate brake to an accelerator pedal arm, a brake pedal arm, a clutch pedal arm, or the like of an automobile and a damper suitable for use in the pedal device.
BACKGROUND ART
Fine control of fuel injection in automotive engines is required for the purposes of low fuel consumption of automobiles and reduction of carbon dioxide, and electronic regulation of the throttle valve opening based on the pressing down of an accelerator pedal has been put to practical use.
In automobiles in which fuel injection of the engine is effected by electronic control, an accelerator cable disposed between an accelerator pedal arm and a throttle valve is normally omitted. With these automobiles without the accelerator cables, the feeling of reaction force with respect to the pedal pressing force differs in comparison with the accelerator cables. Moreover, the hysteresis characteristic in the relationship between the pressing force in the pedal pressing direction and the holding force in the pedal returning direction forms a substantially narrow loop, i.e., the pedal-pressing-force characteristic with respect to the amount of the pedal pressed becomes linear. Therefore, if a general driver who is accustomed to driving an automobile with the accelerator cable drives the automobile without the accelerator cable, there arises a problem in that, for instance, fatigue can occur early when shocks of the acceleration or deceleration of the automobile occur due to the movement of the accelerator pedal during running on a rough terrain, or when the driver tries to fixedly hold the accelerator pedal for a long time during such as high-speed running.
To prevent excessive pressing down by obtaining a large reaction force with respect to the pedal pressing force, if the spring force of a return spring for returning the pedal arm to the initial position of rotation is simply made large, there is a possibility of causing early fatigue to the pedal-pressing foot due to the large reaction force from the return spring during constant-speed running.
Accordingly, a damper has been proposed which imparts a resistance force based on linearly increasing friction between a rotating member rotated by the rotation of the pedal arm and a movable member coming into contact with this rotating member. According to this damper, it is possible to obtain favorable effects such as that the damper has such a hysteresis characteristic that the range of the pedal pressing force allowing the amount of the pedal pressed to be maintained at a fixed level in correspondence with the amount of the pedal pressed can be made large, that the damper can be installed compactly, that the adjustment of the reaction force can be effected very simply, and that a change in its characteristics can be reduced. However, since the hysteresis characteristic is obtained on the basis of dynamic friction and static friction, large resistance based on static friction before leading to dynamic friction is applied to the pedal arm as a reaction force at the start of the pressing down of the pedal from the initial position of rotation of the pedal arm. Consequently, the driver of the automobile who operates the pedal arm receives from the pedal the unpleasant sensation of, as it were, pressing the foot against an immovable wall in the early stage of pressing down, and thus experiences a feeling of fatigue in the pedal operation.
The above-described problem occurs not only with the accelerator pedal arm, but can also occur with, for example, the brake pedal arm, the clutch pedal arm, and the foot-operated parking brake arm.
The present invention has been devised in view of the above-described aspects, and its object is to provide a pedal device for an automobile which excels in the operational feeling, does not cause the driver to experiences a feeling of fatigue in the pedal operation, and makes it possible to enlarge the range of the pedal pressing force allowing the amount of the pedal pressed to be maintained at a fixed level in correspondence with the amount of the pedal pressed, as well as a damper suitable for use in the pedal device.
DISCLOSURE OF INVENTION
A pedal device for an automobile in accordance with a first aspect of the invention comprises a damper for imparting a resistance force to the rotation of a pedal arm, the damper including a movable member which is disposed movably in an axial direction but immovable in a direction about the axis, a rotating member disposed rotatably about the axis and facing the movable member, spring means for resiliently urging the movable member toward the rotating member, and frictional-resistance-force generating means for producing a frictional resistance force as the resistance force in the rotation of the rotating member, and for increasing the frictional resistance force by increasing the spring force of the spring means by causing the movable member to move away from the rotating member in the axial direction against the resiliency of the spring means, wherein a torque which gradually increases from an initial position of rotation of the pedal arm to any angle of 0.5 to 20% of a full angle of rotation thereof is imparted to the rotating member to permit the rotation of the pedal arm, and the rotating member is subsequently rotated in conjunction with the rotation of the pedal arm.
In accordance with the pedal device according to the first aspect, a torque which gradually increases from the initial position of rotation to any angle of 0.5 to 20% of the full angle of rotation is imparted to the rotating member to permit the rotation of the pedal arm, and the rotating member is subsequently rotated in conjunction with the rotation of the pedal arm. Accordingly, at the start of the pressing down of the pedal, the pedal arm is rotated in conjunction with it, with the result that it is possible to eliminate the sensation of being subjected to a large resistance based on the static friction in the frictional-resistance-force generating means. Hence, the driver who operates the pedal arm is able to start the automobile naturally without receiving from the pedal the unpleasant sensation of pressing the foot against, so to speak, an immovable wall, and is able to comfortably effect the pedal operation without experiencing fatigue.
If the angle of rotation of the pedal arm for rotating the rotating member in conjunction with the rotation of the pedal arm is less than 0.5% of the full angle of rotation, the driver receives a large reaction force based on the static friction in the frictional-resistance-force generating means substantially at the same time as the pressing of the pedal. This situation is substantially similar to the case in which the foot is pressed against an immovable wall, and natural starting of the automobile is hence impossible. On the other hand, the angle of rotation of the pedal arm exceeds 20% of the full angle of rotation, the range of the pedal pressing force allowing the amount of the pedal pressed to be maintained at a fixed level in correspondence with the amount of the pedal pressed (the angle of rotation of the pedal arm) becomes small, and this effect can be obtained only at a high speed.
In addition, in accordance with the pedal device according to the first aspect, when the rotating member is rotated by the rotation of the pedal arm due to the pressing down of the pedal, the frictional resistance force which increases occurs in the frictional-resistance-force generating means. Therefore, by virtue of this resistance force, it is possible to prevent fuel from being consumed more than before by, for example, excessively pressing down on the accelerator pedal. Moreover, as the result of the fact that it is possible to enlarge the range of the pedal pressing force in which the angle of rotation of the pedal arm can be maintained at a fixed level in correspondence with the amount of the pedal pressed, the amount of the pedal pressed can be easily maintained at a fixed level in corresponde
Goto Tadashi
Igarashi Yoshiteru
Kojima Masamitsu
Kumazawa Katsutoshi
Bucci David A.
Nixon & Vanderhye
Oiles Corporation
Van Pelt Bradley K.
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