Patent Application
20210396272
Typical gearbox gear trains incorporate several rotating bearings, seals, and other sub-assemblies in the gearbox. The power from the aircraft engines introduce very destructive vibration levels which causes loosening of hardware in the gearbox assemblies. Current methods to prevent parts in the gearbox from coming loose and spreading themselves apart can be very time consuming to assemble. The gearbox gear train components require maintenance personnel to assemble, seat, and preload the components to a required torque while assembling a gearbox or during a gearbox repair. There are many embodiments of hardware that can be used to assist in these tasks. However, such embodiments often require three pieces of hardware to properly function. The hardware also tends to lose preload due to vibration, temperature, the reuse of existing retention hardware, or small radial movement during gearbox operation.
What is needed is a two-piece drive mechanism that preloads and locks components installed in a rotating environment and provides the double locking safety requirement needed in most aircraft for applications operating in an enclosed environment. The mechanism should also hold the required torque for the duration of the drive system operating life without the need for periodic visual inspections.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary, and the foregoing Background, is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter.
The present disclosure provides a double locking nut assembly for a lightweight gearbox. In various embodiments, the assembly includes a double row duplex ball bearing coupled with a double geared shaft inside the lightweight gearbox. A washer coupled with the nut assembly includes a plurality of tangs that are operatively disposed within grooves disposed longitudinally in threads of an adjacent gear to prevent rotation of the washer. A lock nut shoulder containing a serrated deformation locking design that allows ramps of the serration to slide up on the washer while applying installation nut torque. Embodiments of the double locking nut assembly further includes a plurality of opposing tangs that serve as a safety device within the locking nut assembly.
These and other aspects of the present system and method will be apparent after consideration of the Detailed Description and Figures herein. It is to be understood, however, that the scope of the invention shall be determined by the claims as issued and not by whether given subject matter addresses any or all issues noted in the Background or includes any features or aspects recited in this Summary.
Non-limiting and non-exhaustive embodiments of the present invention, including the preferred embodiment, are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense.
The present technology relates to lock nut and tang washer mechanisms that preload and lock components in a rotating environment. In particular, a unique drive system mechanism is presented that preloads and locks the device in a rotating environment and provides a double locking safety requirement needed in most aircraft for applications operating in an enclosed environment. This mechanism holds the required torque for the duration of the drive system operating life without the need for periodic visual inspections. One of various contemplated uses for this mechanism, shown in
With reference to
In various embodiments, the bearing nut properly seats the inner bearing raceways 18 and provides enough stretch in the gear shaft 16 to keep an appropriate gear-bearing assembly preload, while allowing for small changes in surface topography between the clamp-up of all shoulder surfaces. In one aspect of the present technology, the nut-washer shoulder surfaces consist of two sides of the washer 20 and one side of the nut flange 22. The lock nut shoulder 24 opposite the 30-degree tool spline 26 contains a serrated deformation locking design such that a right handed threaded nut would contain a right handed spiral ramp. This allows the ramps of the serration to slide up on the washer while applying the proper installation nut torque required to seat and preload the bearing. One such embodiment is depicted in
In various embodiments, the washer 20 mated with the nut is not allowed to rotate. To prevent this, the washer 20 may include four or more tangs 28. The tangs 28 of the washer 20 lie in four grooves 30 disposed longitudinally in the threads of the gear. The washer's tangs 28 are highlighted in
Although the technology been described in language that is specific to certain structures, materials, and methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures, materials, and/or steps described. Rather, the specific aspects and steps are described as forms of implementing the claimed invention. Since many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. Unless otherwise indicated, all numbers or expressions, such as those expressing dimensions, physical characteristics, etc. used in the specification (other than the claims) are understood as modified in all instances by the term “approximately.” At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter recited in the specification or claims which is modified by the term “approximately” should at least be construed in light of the number of recited significant digits and by applying ordinary rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass and provide support for claims that recite any and all subranges or any and all individual values subsumed therein. For example, a stated range of 1 to 10 should be considered to include and provide support for claims that recite any and all subranges or individual values that are between and/or inclusive of the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or any values from 1 to 10 (e.g., 3, 5.8, 9.9994, and so forth).
