Machine element or mechanism – Control lever and linkage systems – Foot operated
Reexamination Certificate
1999-05-19
2001-12-25
Gutierrez, Diego (Department: 2859)
Machine element or mechanism
Control lever and linkage systems
Foot operated
C033S0010PT, C188S083000, C324S207110, C324S207250, C074S513000
Reexamination Certificate
active
06332374
ABSTRACT:
TECHNICAL FIELD
This invention relates to an accelerator position sensor, drivingly connected to an accelerator pedal in a vehicle, for detecting the accelerator position, and relates in particular to measures of imparting hysteresis to the pressing force characteristic of the accelerator pedal when the accelerator position sensor is drivingly connected directly to the accelerator pedal without interposing any cable therebetween.
BACKGROUND ART
Recently, vehicles equipped with an electronically controlled throttle for example have a tendency to employ an accelerator position sensor which is drivingly connected to the accelerator pedal and detects the position of the accelerator pedal.
A conventional accelerator position sensor will be described here. The accelerator position sensor includes: a fixed member having a boss and fixed on the side of a vehicle body; a rotary member which has a shaft rotatably fitted in the boss and is connected to the accelerator pedal of the vehicle through a cable to rotate in response to pressing and returning operations of the accelerator pedal; a torsion spring, interposed in a position fitted on the boss of the fixed member between the fixed and rotary members, for urging the rotary member into rotation relative to the fixed member in a direction of the returning operation of the accelerator pedal by torque of the torsion spring; and a sensor unit for detecting the angle of rotation of the rotary member relative to the fixed member.
When the accelerator position sensor is placed in an engine room, as schematically shown in
FIG. 4
, the accelerator position sensor a is drivingly connected to a lever d of the accelerating pedal c through the cable b thereby urging the accelerator pedal c into return movement to its original position by torque of the torsion spring. Further, in the engine room, a return spring e is placed for pulling the cable b in a direction of returning the accelerator pedal c to its original position.
Meanwhile, the preferable pressing force characteristic of the accelerator pedal c is generally regarded to as having such hysteresis that the pressing force of the accelerator pedal becomes larger during the pressing operation while it becomes slightly smaller during the returning operation. As for this point, in the conventional accelerator position sensor a mentioned above, though torque of the torsion spring increases or decreases with the angle of rotation of the rotary member, hysteresis of the torsion spring in the rotational direction of the rotary member is comparatively small. However, since the operation of the accelerator pedal c creates sliding resistance in the cable b, the sliding resistance provides the pressing force characteristic having the hysteresis as mentioned above.
Specifically, during the pressing operation of the accelerator pedal c, sliding resistance in the cable b is added to the torque of the torsion spring in the accelerator position sensor a and the tension of the return spring e, thereby increasing the pressing force against the accelerator pedal c. On the other hand, during the returning operation of the accelerator pedal c, the torque and the tension are diminished by the sliding resistance in the cable b, thereby decreasing the pressing force against the accelerator pedal c.
However, when the conventional accelerator position sensor a is drivingly connected directly to the accelerator pedal c without interposing the cable b therebetween, the sensor a cannot use the sliding resistance in the cable b, and therefore is difficult to obtain the above-mentioned hysteresis.
The present invention has been made in view of the above problem, and therefore has its object of obtaining sufficient hysteresis between the pressing and returning operations in terms of the pressing force characteristic of the accelerator pedal by simply making a small change in the internal structure of the accelerator position sensor when the accelerator position sensor is drivingly connected directly to the accelerator pedal without interposing any cable therebetween.
DISCLOSURE OF INVENTION
To attain the above object, in the present invention, a cylindrical resin member rotatable as a unit with a rotary member is disposed between a boss of a fixed member and a torsion spring, the resin member is pressed against the boss by a reaction of torque of the torsion spring so that sliding resistance is produced between the cylindrical resin member and the boss during the rotation of the rotary member, and the sliding resistance provides the above-mentioned hysteresis.
Specifically, an accelerator position sensor of the present invention comprises: a fixed member having a boss and fixed on the side of a vehicle body; a rotary member which has a shaft rotatably fitted in the boss of the fixed member and is connected to an accelerator pedal of the vehicle to rotate in response to pressing and returning operations of the accelerator pedal; a torsion spring, interposed in a position fitted on the boss of the fixed member between the fixed and rotary members, for urging the rotary member into rotation relative to the fixed member in a direction of the returning operation of the accelerator pedal by torque of the torsion spring; a cylindrical resin member which is interposed between the boss of the fixed member and the torsion spring to rotate as a unit with the rotary member and is pressed against the boss by a reaction of the torque of the torsion spring to create sliding resistance to the boss during the rotation of the rotary member; and sensing means for detecting the angle of rotation of the rotary member relative to the fixed member.
With this arrangement, the rotary member is urged into rotation relative to the fixed member in the direction of the returning operation of the accelerator pedal by the torque of the torsion spring. Though the torque is increased or decreased with the angle of rotation of the rotary member, hysteresis of the torque of the torsion spring in the rotational direction of the rotary member is small.
In this case, the cylindrical resin member is interposed between the boss of the fixed member and the torsion spring located around the boss, is pressed at a part of the inner periphery thereof against the boss by a reaction of the torque of the torsion spring, and rotates as a unit with the rotary member. Under this arrangement, the rotation of the rotary member creates sliding resistance between the inner periphery of the cylindrical resin member and the outer periphery of the boss, and the sliding resistance damps the rotation of the rotary member.
Accordingly, output torque developing on the rotary member when rotating opposite to the direction of the returning operation of the accelerator pedal, namely, a pressing force required for the pressing operation of the accelerator pedal, is increased by the damping force over the initial torque since the damping force is added to the initial torque. On the other hand, output torque developing on the rotary member when rotating in the direction of the returning operation of the accelerator pedal, namely, a pressing force required for the returning operation of the accelerator pedal, is decreased by the damping force under the initial torque since the initial torque is damped by the damping force.
Consequently, when the accelerator position sensor is drivingly connected directly to the accelerator pedal without interposing any cable therebetween, the pressing force characteristic of the accelerator pedal can attain sufficient hysteresis between the pressing and returning operations by simply making the small change as described above in the internal structure of the accelerator position sensor.
In the above-mentioned accelerator position sensor, when the torsion spring is interposed under axial compression between the fixed and rotary members, the cylindrical resin member may include a cylindrical body slidably fitted on the boss of the fixed member, and a flange radially outwardly extending from the outer periphery of the cylindrical body and held axially sandwic
Someda Atsushi
Takada Koichi
Bando Chemical Industries Ltd.
Cole Thomas W.
Fernandez Maria
Gutierrez Diego
Nixon & Peabody LLP
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