Accelerating pedal for electronic throttle actuation system

Abstract

Improvements for imparting hysteresis, or dampening, to the shaft of a pedal assembly for an electronic throttle actuation system so that the feel of the pedal simulates the feel of a strictly mechanical system. Pads are resiliently urged against a disk in one embodiment, the disk being affixed to the pedal shaft. In another embodiment, metal rings are resiliently urged against friction rings on the disk.

Description

REFERENCE TO A RELATED APPLICATION

Reference is made to the applicant's commonly assigned co-pending allowed application, Ser. No. 07/157,766 filed Feb. 18, 1988 and entitled, "Pedal Assembly For An Electronic Throttle Actuation System", now U.S. Pat. No. 4,869,220. The state of the art is represented by the references cited in that application.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to an accelerator pedal for an electronic throttle actuation system. More specifically, the invention relates to an improvement in creating hysteresis that acts on the pedal shaft so that the "feel" of pedal operation simulates that which exists in a pedal that is coupled to the throttle strictly by mechanical coupling systems.

In an electronic throttle actuation system for an automotive internal combustion engine, the position of the throttle blade is controlled by an actuator which receives an electrical signal from an electronic control unit. The electronic control unit in turn receives an input signal from a pedal assembly located in the occupant compartment of the vehicle and the system functions to cause the throttle blade to be under the control of the pedal assembly 70, will cause the transducer to supply a corresponding electrical signal to the electronic control unit in the same manner as the transducer of the first embodiment.

Hysteresis is imparted to the rotation of shaft 70 within the device by virtue of the interaction of rings 86 and 90 with disk 88. As can be seen in FIG. 5, wave washer 84 and coil spring 92 serve to urge rings 86 and 90 against opposite sides of disk 88. Disk 88 is provided with friction rings 124 on opposite sides that wipe against rings 86 and 90 in response to rotation of shaft 70. Although the embodiment of FIGS. 5 and 6 does not incorporate a switch such as the switch 40 of the first embodiment, such a switch can be incorporated if desired.

While a preferred embodiment of the invention has been disclosed and described, it should be appreciated that principles are applicable to other embodiments.

Claims

1. In an accelerator pedal control apparatus that remotely controls the throttle valve of an internal combustion engine via electrical signals wherein the apparatus comprises a housing, a shaft journaled on the housing, means for imparting rotational motion to the shaft, a spring rotationally biasing the shaft toward a first position corresponding to the throttle valve being in closed or substantially closed position, an electrical sensor that is operated by the rotation of said shaft to positions away from said first position to signal the amount of rotation that is being imparted to the shaft, and a friction mechanism that acts on the shaft to dampen shaft rotation, the improvement in said friction mechanism characterized by a disk affixed to said shaft, friction elements on opposite sides of said disk, a pair of formed metal elements acting to sandwich said friction elements and said disk, and resilient means urging said formed metal elements to forcefully sandwich said friction elements and said disk.

2. The improvement set forth in claim 1 in which said friction elements are a pair of pads that are secured to said formed metal elements, and said resilient means is integrally formed with said formed metal elements so that said formed metal elements and said resilient means are a single part.

3. The improvement set forth in claim 2 in which said single part is a formed metal clip having a base disposed on said housing and side portions at angles to said base, said side portions containing said pads.

4. The improvement set forth in claim 3 in which said side portions comprise sides that extend from said base and are inwardly reversed turning back onto themselves, said friction pads being disposed on the portions that are reverse-turned back onto themselves.

5. The improvement set forth in claim 1 in which said friction elements are a pair of circular rings on opposite sides of said disk and said formed metal elements are rings that are concentric with said friction elements.

6. The improvement set forth in claim 5 including keying means keying the rings to the housing.

7. The improvement set forth in claim 6 in which each metal ring comprises a pair of diametrically opposite tabs and said keying means comprises slots located in said housing within which said tabs are disposed.

8. The improvement set forth in claim 7 in which a different set of slots receives the tabs of one metal ring from the slots receiving the tabs of the other metal ring.

9. The improvement set forth in claim 5 in which said resilient means comprises a wave washer acting on one metal ring and a coil spring acting on the other metal ring.

10. The improvement set forth in claim 5 including a pair of fingers that project axially from the input shaft of said electrical sensor and a bar on said disk that projects axially to fit between the fingers of the electrical sensor input shaft for coupling rotation of the disk to the input shaft of the sensor.

11. The improvement set forth in claim 10 in which the sensor comprises barbs that snap into slots in the housing.

12. The improvement set forth in claim 9 including barbs on said sensor that are disposed within said slots and snap into apertures in the wall of said slots for mounting the sensor on the housing. 13. In an accelerator pedal control apparatus that remotely controls the powerplant of an automotive vehicle via electrical signals wherein the apparatus comprises a housing mounted on the vehicle, a shaft journaled on the housing for rotary motion, a foot pedal for imparting rotary motion to the shaft, a spring causing the shaft to be rotary biased toward a first position corresponding to the absence of foot actuation of the pedal, an electrical sensor that is operated by the rotary motion of the shaft to positions away from said first position to signal the amount of rotary motion imparted to the shaft away from said first position by the pedal, and a friction mechanism that acts on the shaft to dampen rotary motion of the shaft, the improvement in said friction mechanism characterized by a disk affixed to said shaft, friction elements on opposite sides of said disk, a pair of formed metal elements acting to sandwich said friction elements and said disk, and resilient means urging said formed metal elements to forcefully sandwich said friction elements and said disk. 14. The improvement set forth in claim 13 in which said friction elements are a pair of pads that are secured respectively to said pair of formed metal elements, and said resilient means is integrally formed with said pair of formed metal elements so that said formed metal elements and said resilient means are embodied in a single part. 15. The improvement set forth in claim 14 in which said single part is a formed metal clip having a base disposed on said housing and side portions at angles to said base, said side portions containing said pads. 16. The improvement set forth in claim 15 in which said side portions comprise sides that extend from said base and are inwardly reverse turned back onto themselves, said friction pads being disposed on the portions of said sides that are inwardly reverse-turned back onto themselves. 17. The improvement set forth in claim 13 in which said friction elements are a pair of circular rings on opposite sides of said disk and said formed metal elements are metal rings that are concentric with said friction elements. 18. The improvement set forth in claim 17 including keying means keying the rings to the housing. 19. The improvement set forth in claim 18 in which each metal ring comprises a pair of diametrically opposite tabs and said keying means comprises slots located in said housing within which said tabs are disposed. 20. The improvement set forth in claim 19 in which a different set of said slots receives the tabs of one metal ring from a set of said slots receiving the tabs of the other metal

ring. 21. The improvement set forth in claim 17 in which said resilient means comprises a wave washer acting on one metal ring and a coil spring acting on the other metal ring. 22. The improvement set forth in claim 17 including a pair of fingers that project axially from an input shaft of said electrical sensor and a bar on said disk that projects axially to fit between the fingers of the electrical sensor input shaft for coupling rotation of the disk to the input shaft of the sensor. 23. The improvement set forth in claim 22 in which the sensor comprises barbs that snap into slots in the housing. 24. The improvement set forth in claim 21 including barbs on said sensor that are disposed within said slots and snap into apertures in the wall of said slots for mounting the sensor on the housing. 25. An accelerator pedal control apparatus adapted for installation and use in an automotive vehicle in association with a foot pedal to provide remote control of a powerplant of the vehicle via electrical signals wherein the apparatus comprises a housing adapted to be mounted on the vehicle, a shaft that is journaled on the housing for rotary motion and that is adapted to execute rotary motion in response to the operation of such a pedal, a spring causing the shaft to be rotary biased toward a first position corresponding to the absence of foot actuation of such a pedal, an electrical sensor that is disposed on the housing and is operated by the rotary motion of said shaft to positions away from said first position to signal the amount of rotary motion imparted to the shaft away from said first position against said spring, and a friction mechanism that is disposed on the housing to act on the shaft to dampen rotary motion of the shaft, characterized in that said friction mechanism comprises a member that is operated by said shaft to execute rotary motion in unison therewith, friction elements on opposite sides of said member, a pair of formed metal elements acting to sandwich said friction elements and said member, and resilient means urging said formed metal elements to forcefully sandwich said friction elements and said member. 26. accelerator pedal control apparatus as set forth in claim 25 characterized further in that said friction elements are disposed to execute rotary motion with said member, and said pair of formed metal elements are constrained on said housing against rotary motion whereby said friction elements wipe against said formed metal elements during rotary motion of said shaft. 27. accelerator pedal control apparatus as set forth in claim 26 characterized further in that said friction elements are a pair of circular rings on opposite sides of said disk and said formed metal elements are metal rings that are concentric with said friction elements. 28. accelerator pedal control apparatus as set forth in claim 25 characterized further in that said friction elements are secured to said formed metal elements, and said formed metal elements are constrained on said housing against rotary motion whereby said member rides between said friction

elements during rotary motion of said shaft. 29. accelerator pedal control apparatus as set forth in claim 25 characterized further in that said spring comprises at least one torsion spring that is coaxially disposed about said shaft. 30. accelerator pedal control apparatus as set forth in claim 25 characterized further in that said member is a disk affixed to said shaft.