BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a plan view of an apparatus employing a gear set;
FIG. 2 is a perspective view of an embodiment of the invention;
FIG. 3 is a perspective view of another embodiment of the invention;
FIG. 4 is a perspective view of another embodiment of the invention;
FIG. 5 is a perspective view of another embodiment of the invention; and
FIG. 6 is a perspective view of another embodiment of the invention.
DETAILED DESCRIPTION
Referring now to the drawings, there is seen in FIG. 1 one embodiment of the invention incorporated into an electronic throttle control (ETC) 10. It is understood, however, that the invention is applicable to any type of apparatus having one or more gears where dampening of the gear stopping movement is desired.
In the ETC 10, a first gear 12 is mounted in a gear housing 14. The first gear may be mounted in meshing engagement with one or more additional gears as required by the particular controller design being employed. For example, in the embodiment of FIG. 1, first gear 12 may be placed in meshing engagement with a second gear 16 which is coaxially mounted to a third gear 18 mounted in meshing engagement with a fourth gear 20. A shaft (not shown) extends from the center 12a of the first gear 12 for attaching to and controlling the movement of a component (not shown) such as a throttle valve blade, for example.
Referring to FIG. 2, a prior art gear stop 11 having a rigid back fin 11a is mounted on gear 12. A stop 13 is mounted to the gear housing (not shown in FIG. 2) to stop the turning of gear 12 at the appropriate location. Since back fin 11a is rigid, it does not absorb an appreciable amount of the stopping force as gear stop 11 strikes cylindrical stop 13. This may result in the gear teeth absorbing the force resulting in damaged gear teeth.
Referring to FIGS. 3-5, a rotational speed damper 30 is mounted to the first gear 12, and a stop 32 is mounted to the gear housing 14 (gear housing 14 not shown in FIGS. 3-5). In an alternate embodiment, the damper 30 may be mounted to the gear housing 14 and the stop 32 may be mounted to the gear 12. The stop 32 and the damper 30 are respectively positioned such that they come into contact with each other as the first gear 30 approaches a first stopping point. The rotational speed damper 30 is operable to dampen the speed of the first gear 12 by gradually decreasing the rotational velocity and angular acceleration of the first gear 12 over a time period beginning at the time the damper 30 contacts the stop 32 and ending at the time the first gear reaches its first stopping point.
The damper 30 may comprise one or more resilient cantilevers 34 and the cantilevers may be of the same or different lengths as shown. The cantilevers 34 may contact or be spaced from each other as shown. In yet a further embodiment, a connecting rib 36 may interconnect the spaced cantilevers 34 as seen in FIG. 5. The cantilevers 34 may formed of a first resilient material such as plastic, for example. A spacer element 38 may be provided and formed of a second material and positioned in the space between the cantilevers 34 as shown in the embodiment of FIG. 4. The second material may be less stiff or more stiff than the first material to obtain the desired dampening effect. The cantilevers 34 may shorten in length in a direction away or toward the stop 32. In the embodiments of FIGS. 3-5, cantilevers 34 shorten in a direction away from stop 32.
In yet another embodiment seen in FIG. 6, the damper 40 may be a leaf spring or clip including first and second ends 40a and 40b, respectively, with one of the ends 40a anchored to the housing or gear, and the other end 40b left unanchored and free such that the spring 40 flexes to absorb a force being applied adjacent the free end 40b thereof by first stop 50. A second stop 52 may be positioned in spaced, adjacent relationship to the spring free (second) end 40b on the side of the spring 40 opposite the first stop 50, the second stop 52 defining the flexing limit of the spring 40 upon the first stop 50 pressing spring free end 40b against second stop 52. The first stop 50 may be positioned on the gear 12 and said second stop 52 may be positioned on the housing 14.
While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.
Patent Application
20080067029
