Patent Application
20210231016
This disclosure relates in general to the field of balancing rotating apparatuses, and more particularly, to a static balancing of a rotor blade assembly of an aircraft.
This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
Aircraft rotor blades are often manufactured with an assembly of components, which can result in variations from one rotor blade to the next in weight and weight distribution. Variations between rotor blades result in rotor blade assemblies that are unbalanced. In operation, unbalanced rotor blade assemblies produce excessive vibration and can result in failure of the rotor blade assembly.
An exemplary static rotor blade assembly balancing tool includes a vertical rod having a top end with a tip located at the top end on a vertical axis of the rod and a sleeve having a bore terminating at a socket, in use the rod is disposed in the bore and the tip and the socket form a pivot connection where the sleeve is balanced to settle in a level position with a vertical axis of the sleeve coaxial with the vertical axis of the rod, and the sleeve has an outer profile configured to mount a hub of a rotor blade assembly.
An exemplary method for balancing a rotor blade assembly includes connecting a sleeve in a hub of a rotor blade assembly, the sleeve having a bore terminating at a socket, mounting the sleeve and the rotor blade assembly on a vertical rod having a tip, where the vertical rod is disposed in the bore and the tip and the socket are in pivoting contact, measuring a balance of the rotor blade assembly and balancing the rotor blade assembly if it is not balanced.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of claimed subject matter.
The disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.
It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various illustrative embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. For example, a figure may illustrate an exemplary embodiment with multiple features or combinations of features that are not required in one or more other embodiments and thus a figure may disclose one or more embodiments that have fewer features or a different combination of features than the illustrated embodiment. Embodiments may include some but not all the features illustrated in a figure and some embodiments may combine features illustrated in one figure with features illustrated in another figure. Therefore, combinations of features disclosed in the following detailed description may not be necessary to practice the teachings in the broadest sense and are instead merely to describe particularly representative examples. In addition, the disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not itself dictate a relationship between the various embodiments and/or configurations discussed.
In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “inboard,” “outboard,” “above,” “below,” “upper,” “lower,” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction. As used herein, the terms “connect,” “connection,” “connected,” “in connection with,” and “connecting” may be used to mean in direct connection with or in connection with via one or more elements. Similarly, the terms “couple,” “coupling,” and “coupled” may be used to mean directly coupled or coupled via one or more elements.
Sleeve 108 has an outer profile 118 configured to mount and connect to a hub of a rotor blade assembly. Sleeve 108 may be constructed to simulate the mast that corresponds with the rotor blade assembly to be balanced. A nut 120, e.g. a mock mast nut, is connectable to the top end 122 of sleeve 108 to secure the rotor blade assembly on the sleeve. The diameter 124 (
The pivoting connection of tip 104 and socket 112 is configured to minimize friction therebetween and to promote detection of an unbalance rotor blade assembly. In accordance to an embodiment, tip 104 and socket 112 are constructed of steel to facilitate the required strength to support the rotor blade assembly and minimize the surface area of the contact between tip 104 and socket 112. In accordance with an embodiment, tip 104 and socket 112 are constructed of heat treated steel.
An exemplary method of balancing a rotor blade assembly is now described with reference to
After rotor blade assembly 138 is secured to sleeve 108, vertical rod 102 is positioned in bore 110 with tip 104 in pivoting contact (pivot point) with socket 112. Vertical rod 102 supports rotor blade assembly 138 above ground level 148. In the example illustrated in
Once rotor blade assembly 138 is positioned on tip 104 of rod 102, the balance of rotor blade assembly 138 is measured. For example, when the rotor blade assembly is balanced a horizontal axis 154 of rotor blade assembly 138 will be orthogonal to vertical. The level, or balance, of rotor blade assembly may be measured using one or more bubble levels 156. In an example, bubble level 156 is placed on the hub, for example, bubble levels 156 may be positioned on the hub proximate each blade root end. If the rotor blade assembly is not balanced, weights 158 may be added to one or more blades 138.
In
Conditional language used herein, such as, among others, “can,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include such elements or features.
The term “substantially,” “approximately,” and “about” is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. The extent to which the description may vary will depend on how great a change can be instituted and still have a person of ordinary skill in the art recognized the modified feature as still having the required characteristics and capabilities of the unmodified feature. In general, but subject to the preceding, a numerical value herein that is modified by a word of approximation such as “substantially,” “approximately,” and “about” may vary from the stated value, for example, by 0.1, 0.5, 1, 2, 3, 4, 5, 10, or 15 percent.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure and that they may make various changes, substitutions, and alterations without departing from the spirit and scope of the disclosure. The scope of the invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open group. The terms “a,” “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded.
