Patent Application
20190249715
The present application is directed to a force transmitting remote control assembly, and more particularly to a force transmitting remote control assembly having ball guides that reduce and/or eliminate jamming of rolling members.
Known force transmitting remote control assemblies such as ball bearing control assemblies are sometimes provided with ball guides that interact with rolling members at only one location. During normal service the ball guide can kink or bend creating a large enough clearance, enabling a rolling member to, if displaced, lodge itself between the ball guide and a force transmitting member. Alternatively, the rolling member may lodge itself between the ball guide and a stationary race. The lodged rolling member can then jam the force transmitting remote control assembly rendering it unusable. This can lead to an undesired control failure of large machinery.
Furthermore, many force transmitting remote control assemblies are not configured to withstand relatively harsh environmental conditions including large temperature variations, environmental vibration, etc. Accordingly, improvements to force transmitting remote control assemblies are desired.
The following presents a simplified summary in order to provide a basic understanding of some example aspects of the disclosure. This summary is not an extensive overview. Moreover, this summary is not intended to identify critical elements of the disclosure nor delineate the scope of the disclosure. The sole purpose of the summary is to present some concepts in simplified form as a prelude to the more detailed description that is presented later.
According to one aspect of the present disclosure, the subject application involves a ball bearing control assembly. The ball bearing control assembly includes a flexible sheath, where the sheath is generally cylindrical. The ball bearing control assembly also includes a pair of stationary races, each stationary race defines a first raceway. The ball bearing control assembly further includes a plurality of rolling members, where the rolling members have a center point and are in rolling contact with the first raceway. The ball bearing control assembly still further includes a force transmission member, where the force transmission member defines a second raceway on each of opposing sides. The rolling members are configured to be in rolling contact with the second raceway, and the force transmission member is configured to translate axially within the sheath. The ball bearing control assembly also includes a ball guide, where the ball guide includes structure configured to interact with the rolling members at two locations on each axial side of the rolling members. The two locations are positioned at different distances from the second raceway. The stationary races are located between the ball guide and the flexible sheath, where the stationary races are located diametrically opposite each other. The ball guide is located between the stationary races and the force transmission member.
According to another aspect of the present disclosure, the subject application involves a ball bearing control assembly. The ball bearing control assembly includes a flexible sheath, where the sheath is generally cylindrical. The ball bearing control assembly further includes a pair of stationary races, each stationary race defines a first raceway. The ball bearing control assembly still further includes a plurality of rolling members, where the rolling members have a center point and are in rolling contact with the first raceway. The ball bearing control assembly also includes a force transmission member, where the force transmission member defines a second raceway on each of opposing sides. The rolling members are configured to be in rolling contact with the second raceway, and the force transmission member is configured to translate axially within the sheath. The ball bearing control assembly further includes a pair of ball guides, where the ball guides include structure configured to interact with the rolling members at two locations on each axial side of the rolling members. The two locations are positioned at different distances from the second raceway. The stationary races are located between the flexible sheath and one of the ball guides, where the stationary races are located diametrically opposite each other. The ball guides are located between the stationary races and the force transmission member.
According to still another aspect of the present disclosure, the subject application involves a ball bearing control assembly. The ball bearing control assembly includes a flexible sheath that is generally cylindrical. The ball bearing control assembly also includes a pair of stationary races and each stationary race defines a first raceway. The ball bearing control assembly further includes a plurality of rolling members having a diameter. The rolling members have a center point and are in rolling contact with the first raceway. The ball bearing control assembly still further includes a force transmission member that defines a second raceway on each of opposing sides. The rolling members are configured to be in rolling contact with the second raceway, and the force transmission member is configured to translate axially within the sheath. The ball bearing control assembly also includes a ball guide that is located between one of the pair of stationary races and the force transmission member. The majority of the rolling member is constrained. The stationary races are located between the ball guide and the flexible sheath diametrically opposite each other.
The foregoing and other aspects of the present disclosure will become apparent to those skilled in the art to which the present disclosure relates upon reading the following description with reference to the accompanying drawings, in which:
Example embodiments that incorporate one or more aspects of the present disclosure are described and illustrated in the drawings. These illustrated examples are not intended to be a limitation on the present disclosure. For example, one or more aspects of the present disclosure can be utilized in other embodiments and even other types of devices. Moreover, certain terminology is used herein for convenience only and is not to be taken as a limitation on the present disclosure. Still further, in the drawings, the same reference numerals are employed for designating the same elements.
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As will be discussed further below, the ball bearing control assembly 20 and particularly the force transmission member 26 are designed to translate an input load at a first location to an output load at a second location. The input load and the output load are typically linear translation, however the ball bearing control assembly 20 is configured to enable the assembly to both bend and helix (i.e., twist) such that the input load and the output load do not have to be located along a continuous line or within a single plane. In fact, the input load and the output load do not have to have any particular geometric relationship to each other.
In order to accomplish this load transmission along a non-linear path, the force transmission member 26 translates axially within the flexible sheath 24 in the direction shown by arrow 36. The force transmission member 26 is interposed between two stationary races 38 that each lie in planes generally parallel to the force transmission member 26. Portions of the stationary races 38 that are located proximate to the flexible sheath 24 can include rounded surfaces 40 configured to cooperate with the sheath's interior surface 44. The stationary races 38 can be comprised of a nickel-based alloy and can be hardened to a particular hardness in order to reduce wear and increase the expected life cycle of the ball bearing control assembly 20. In one example, the stationary races 38 have material properties enabling the stationary races 38 to withstand heating and cooling cycles to relatively high temperatures without tempering the material or taking a permanent shape deformation. Similar to the force transmission member 26, the stationary races 38 include a first raceway 46 that can have a relatively smooth surface.
The ball bearing control assembly 20 further includes rolling members 48 located between the force transmission member 26 and each stationary race 38. In one example, the rolling members 48 can be ball bearings and can include a composition that is ceramic, such as a silicon nickel composition, however any composition is contemplated, so long as the composition can withstand the required operating conditions expected in typical use, such as near or within frames of jet engines. The rolling members 48 are configured to cooperate with the force transmission member 26 and the stationary races 38 to produce a relatively high efficiency linear translation of the force transmission member 26.
As is often necessary to maintain this relatively high efficiency, the rolling members 48 are maintained at particular positions relative to the force transmission member 26 and the stationary races 38. The ball bearing control assembly 20 further includes a ball guide 50 interposed between the force transmission member 26 and the stationary races 38.
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In another example, the structure that interacts with the rolling member 48 can include curved surfaces corresponding to the rolling member 48 outside diameter, etc. In fact, many variations of structures can meet the intent of the structures configured to interact with the rolling members 48 at two locations on each axial side of the rolling members 48 with the two locations being positioned at different distances from the second raceway 28 of the force transmission member 26.
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The outermost piece 66 of the two-piece stack 64 can include a series of embossed areas 68, each embossed area 68 defining an aperture 70 through which a portion of a rolling member 48 may pass. The innermost piece 74 of the two-piece stack 64 can include a regular interval of apertures 76 through which a portion of the rolling members 48 can pass. In one example, a diameter of the apertures 70, 76 is greater than a diameter of the rolling members 48, such that the rolling member 48 is free to pass entirely through the ball guide 50. In another example, the rolling member 48 can be captured within the ball guide 50. In this example, a diameter of the rolling member 48 can be greater than the diameter of the apertures 70, 76, and the rolling member is prevented from leaving the bounds of the ball guide 50, with relatively small portions of the rolling member 48 passing through the outermost piece 66 and the innermost piece 74.
The effect of this two-piece stack 64 interacting with the rolling members 48 at two different locations (e.g., edges 60) along lines 56, 58 (best seen in
For example, known ball bearing control assemblies can include a ball guide with an interaction point with the rolling member at only one location. In other examples, the majority of the rolling member is not constrained in an axial direction. In some cases during its service life, the ball guide to can buckle or kink. Also, as the ball bearing control assembly bends to accommodate a particular path through an airframe, internal clearances between the components of the assembly increase. These buckles, kinks, and increased internal clearances can create a larger space into which the rolling member can pass and get stuck between a portion of the ball guide and the force transmission member. In these cases, the ball bearing control assembly can jam and is rendered ineffective. A jammed ball bearing control assembly can be quite problematic in the field such as in a jet engine throttle control. As such, the ball bearing control assembly 20 ball guide 50 described herein includes interaction points (e.g., edges 60) with the rolling members 48 at two locations on each axial side of the rolling member 48 (at lines 56, 58) in order to reduce and/or prevent the occurrence of the rolling member 48 lodging itself between a portion of the ball guide 50 and the force transmission member 26.
Each piece 66, 74 of the ball guide 50 can be constructed of any suitable material. In one example, each piece 66, 74 is constructed of stainless steel. In another example, one or more of the pieces 66, 74 is constructed of a nickel-based alloy. The individual pieces 66, 74 of the ball guide 50 can be stampings and can be attached to each other by any suitable method including, but not limited to, spot welding.
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It is to be appreciated that the described apparatus is scalable to various sizes and applications, in one example the ball bearing control assembly 20 can be between several feet and hundreds of feet long. As is to be appreciated, the various components of the ball bearing control assembly 20 can be designed and sized to accommodate a wide variety of particular applications depending upon many factors such as force requirements, service life requirements, available space envelope, etc.
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It is also to be noted that
Additionally, two contact locations 160 can be located on each axial side 259, 261 of the rolling members 148. As shown in
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The ball guide 250 includes enlarged volumes 264 proximal to the apertures 270 that permit a portion of the rolling member 248 to pass through the ball guide 250. The shown example demonstrates how the majority of the rolling member 248 is constrained in an axial direction (parallel to axial centerline 254). This means that a majority of the diameter of the rolling member 248 is not able to pass between any gap that exists between the ball guide 250 and the stationary race 238. This prevents the rolling member 248 from moving to a position in the area of 266 in
While there may be a multitude of structures to help ensure that majority of the rolling member 248 is constrained, two examples will be described. In a first example, the ball guide 250 includes structure 264 having a dimension 270 measured on a perpendicular between the force transmission member 226 and one of the pair of stationary races 238. The length of the dimension 270 is equal to or greater than the majority of the rolling member 248. For certain arrangements, this relationship between dimension 270 and the length of the diameter of the rolling member 248 can prevent passage of the rolling member into areas 266 and 268.
In another example, the ball bearing control assembly 220 includes a free space dimension 274 measured on a perpendicular between the force transmission member 226 and one of the pair of stationary races 238. The ball guide 250 includes structure having an object dimension 270 measured on a perpendicular between the force transmission member 226 and one of the pair of stationary races 238. The difference between the free space dimension 274 and the object dimension 270 is less than a diameter of the rolling member 248. This relationship between object dimension 270 and the length of the free space dimension 274 can prevent passage of the rolling member into areas 266 and 268. This remains true even when the ball guide 250 is displaced to a position that touches either the force transmission member 226 or the stationary race 238 which may occur in a bend location or kink. In other words, even if the ball guide 250 is displaced transversely from the axial centerline 254 (up or down in
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There are several benefits that can be appreciated through the structure of the present disclosure. Primarily, the reduction and/or elimination of the possibility of the rolling member 48 moving from an intended location to a position between a ball guide 50 and a stationary race 38 where the rolling member can then jam the operation of the ball bearing control assembly 20. In one example, the ball bearing control assembly 20 with the structure and materials discussed can attain an overall efficiency above 90%. Another benefit can include the fact that the individual components of the ball bearing control assembly 20 can be heat-treated while maintaining corrosion resistance at relatively high temperatures. Yet another benefit can include a lack of permanent shape deformation with frequent heating and cooling cycles.
Furthermore, the ball bearing control assembly 20 as described is designed to withstand great temperature variation and vibration while having a relatively high number of operating cycles in its expected life duty cycle. Another potential benefit can include the nonmagnetic properties of the ball bearing control assembly as a whole, enabling the ball bearing control assembly 20 to be unaffected by magnetic fields that may exist near the path of the ball bearing control assembly 20. Finally, the described device permits very high tensile and compression forces to be transmitted, even in sinuous paths having bends of small radius of curvature, in any plane, with relatively high efficiency and relatively high accuracy.
While this disclosure has been written in conjunction with the specific embodiments described above, it is evident that many alternatives, combinations, modifications and variations are apparent to those skilled in the art. Accordingly, the described embodiments of this disclosure, as set forth above are intended to be illustrative only, and not in a limiting sense. Various changes can be made without departing from the spirit and scope of this disclosure. Combinations of the above embodiments and other embodiments will be apparent to those of skill in the art upon studying the above description and are intended to be embraced therein. Therefore, the scope of the present disclosure is defined by the appended claims, and all devices, processes, and methods that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
