Patent Application
20140140759
The following description relates to a coupling assurance assembly for an intermediate shaft in a steering column, and in particular, a coupling assurance assembly configured to prevent an improper connection between the intermediate shaft and an adjacent shaft in the steering column.
An intermediate shaft is commonly positioned in a steering column between an output shaft of the steering column, i.e., a steering shaft, and an input shaft of a steering gear. The intermediate shaft is used to transfer steering torque from the output shaft to the input shaft of the steering gear.
A conventional intermediate shaft may include a tubular shaft element and a solid shaft element telescoped into the tubular shaft element. A yoke assembly, for example, of a universal joint assembly, may be used to couple the intermediate shaft to an adjacent shaft. In one configuration, the intermediate shaft may include a first inner yoke rigidly attached at a first end of the intermediate shaft and a second inner yoke rigidly attached at a second end of the intermediate shaft. The first inner yoke is coupled to a first outer yoke of the input shaft of the steering gear and the second inner yoke is coupled to a second outer yoke of the output shaft of the steering column, for example, with a cross trunnion or spider. The first and second outer yokes may be fixed to the respective input shaft and output shaft by way of a bolt extending through the respective yoke and shaft.
Improper coupling between the intermediate shaft and an adjacent shaft, such as the steering shaft may lead to loss of steering function. Improper coupling may result from a yoke being joined to an adjacent shaft without a bolt to secure the yoke to the adjacent shaft. In this scenario, the shaft and yoke may appear to be properly joined during assembly. However, the yoke and adjacent shaft may later separate causing loss of steering function because they are not secured to one another with the bolt or other fastener. Also, the yoke and shaft may be assembled but the bolt is fastened outside of an interlocking area between the yoke and shaft, or the bolt may be prematurely installed so that it does not secure the yoke and shaft together.
Accordingly, it is desirable to provide an assembly where improper connections between the intermediate shaft and adjacent shafts are visually detectable so that improper connections may be identified and corrected.
According to an exemplary embodiment of the present invention, there is provided a coupling assurance assembly for an intermediate shaft in a steering column including a shaft having a longitudinal bore extending a first longitudinal axis and a fastening receptacle for receiving a fastener, a yoke having a cross hole for receiving the fastener, and a biasing device configured to urge the shaft and the yoke apart from each other.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Referring now to the Figures, where the invention will be described with reference to specific embodiments, without limiting same,
With further reference to
The shaft 130 extends along a first longitudinal axis ‘L1’ and includes a bore 132. The bore 132 has a diameter or width, i.e., an inner diameter/width of the shaft 130, that is larger than an outer diameter of the attaching section 124 of the yoke 120, so that the attaching section 124 may be received within the bore 132. A seat 134 extends around the bore 132 and serves as a seat for the biasing device 140 within the bore 132. In an exemplary embodiment, the shaft 130 is a steering column shaft.
The shaft 130 further includes a fastening receptacle 136. In an exemplary embodiment, the fastening receptacle 136 is an opening 136 extending through the shaft 130 in a direction perpendicular to the first longitudinal axis ‘L1’. In an exemplary embodiment, the opening 136 extends along a cross shaft axis ‘S’ that intersects the first longitudinal axis ‘L1’. The opening 136 may be formed as two diametrically opposed openings centered on the cross shaft axis ‘S’, extending through the shaft 130 and in communication with the bore 132.
The biasing device 140 is seated on the seat 134 in the bore 132 of the shaft. The biasing device 140 is movable between a first position where it extends across the opening 136 of the shaft 130 (
In an exemplary embodiment the biasing device 140 is a coil spring. In an exemplary embodiment, the coil spring extends from the seat 134 to an open end of the shaft 130, or beyond, when uncompressed. The coils of the coil spring 140 may be spaced so that the fastener cannot be forced through spaces between the coils. In addition, in an exemplary embodiment, with the attaching section 124 fully inserted into the bore 132 of the shaft, the coil spring is not at a solid height. That is, in the second position, a spacing may be maintained between the coils of the coils spring. The coil spring 140 may be centered on the first longitudinal axis ‘L1’. However, it is understood that the coil spring may be suitably disposed in off-axis positions as well.
In addition, in the assembled condition, the cross hole 122 of the yoke 120 is aligned with the opening 136 of the shaft 130. Accordingly, the cross yoke axis ‘C’ and the cross shaft axis ‘S’ are aligned, and the fastener (not shown) may be received through the cross hole 122 and opening 136 to fix the yoke 120, and thus, the intermediate shaft, to the shaft 130. In an exemplary embodiment, the fastener may be a bolt, or other suitable fastening mechanism.
The biasing device 140 is biased toward the first position. Thus, when the attaching section 124 of the yoke is inserted into the bore 132, the yoke 120 is urged outward from the bore 132 of the shaft 130. Accordingly, if a fastener is not installed through the cross hole 122 and opening 136, the attaching section 124, and thus the yoke 120, will be urged out of the shaft 130. Thus, improper assembly by omitting the fastener may be readily noticed and corrected before the steering column is packaged and shipped. Further still, the biasing device 140 blocks the opening 136 in the shaft 130 when in the first position. Thus, the fastener may not be received in the opening 136 if the biasing device is not compressed to a position, i.e., the second position, clear of the opening 136. Accordingly, the fastener may not be prematurely installed.
With further reference to
The shaft 230 extends along a first longitudinal axis ‘L1’ and includes a shaft bore 232. The shaft 230 has an outer diameter/width that is less than a diameter/width of the yoke bore 222 so that the shaft 230 may be received within the yoke bore 222. In an exemplary embodiment, the shaft 230 is a steering column shaft.
The shaft 230 further includes a fastening receptacle 234. In an exemplary embodiment, the fastening receptacle 234 is a notch 234 formed in an outer periphery of the shaft 230. The notch 234, sometimes referred to as a “whistle notch”, extends along a notch axis ‘N’. In an exemplary embodiment, the notch axis ‘N’ is spaced from, and extends generally perpendicular to the first longitudinal axis ‘L1’.
The yoke bore 222 extends along a second longitudinal axis ‘L2’. The cross hole 224 extends along a cross yoke axis ‘C’. In an exemplary embodiment, the cross yoke axis ‘C’ is spaced from the second longitudinal axis ‘L2’ and extends generally perpendicular to the second longitudinal axis ‘L2’.
The biasing device 240 is seated on the seat 226 in the yoke bore 222. The biasing device 240 is movable between a first position where it extends across the cross hole 224 (
In an exemplary embodiment the biasing device 240 is a coil spring and extends along a third longitudinal axis ‘L3’ within the yoke bore 222. The coil spring 240 may be positioned at least partially in the internal slot 228 of the yoke bore 222. In an exemplary embodiment, the coil spring extends from the seat 222 to an open end of the yoke bore 222, or beyond, when uncompressed. The coils of the coil spring may be spaced so that the fastener cannot be forced through spaces between the coils. The coil spring 240 may be formed with a substantially constant or varying width or diameter. The width or diameter of the coil spring 240 in the region of the cross hole 224 is sufficient to block access to the cross hole 224 by a fastener when the coil spring is in the first position. The width or diameter of the coil spring 240 may be larger than, approximately equal to, or smaller than a diameter of the cross hole 224 in the region of the cross hole 224.
In addition, in the assembled condition, the notch 234 of the shaft 230 is aligned with the cross hole 224 of the yoke 220. Accordingly, the notch axis ‘N’ and the cross yoke axis ‘C’ are aligned so that the fastener (not shown) may be received through the cross hole 224 and the notch to secure the yoke 220, and thus, the intermediate shaft, to the shaft 230.
The biasing device 240 is biased toward the first position. Thus, when the shaft 230 is inserted into the yoke bore 222, the shaft 230 is urged outward from the yoke bore 222. Accordingly, if a fastener is not installed through the cross hole 224 and notch 234, the shaft 230 will be urged out of the yoke bore 222. Thus, improper assembly by omitting the fastener may be readily noticed and corrected before the steering column is packaged and shipped. Further still, the biasing device 240 blocks the cross hole 224 of the yoke when in the first position. Thus, the fastener may not be received in the cross hole 224 if the biasing device 240 is not compressed to a position, i.e., the second position, clear of the cross hole 240. Accordingly, premature installation of the fastener may be prevented.
In the exemplary embodiments above, the biasing device 140, 240 is a coil spring. The coil spring may be wound to fit a cross section of a shaft. For example, the coil spring may be wound as a double-D spring to fit a double-D cross section that is commonly found in shafts. In addition, the spacing between coils of the coil spring may be uneven or even. Uneven coil spacing may be desirable to minimize a solid height of the spring while maintaining a sufficient barrier against premature installation of the fastener.
In an exemplary embodiment, the yoke 320 is connected at one end to the intermediate shaft of the steering column. The shaft 330 is positioned at an opposite end of the yoke 320 than the intermediate shaft. For example, and with reference to
Referring again to
The shaft 330 further includes a fastening receptacle 334. In an exemplary embodiment, the fastening receptacle 334 is a notch 334, sometimes referred to as a “whistle notch”, formed in an outer periphery of the shaft 330. The notch 334 extends along a notch axis ‘N’. In an exemplary embodiment, the notch axis ‘N’ is spaced from, and extends generally perpendicular to the first longitudinal axis ‘L1’.
The yoke bore 322 extends along a second longitudinal axis ‘L2’. The cross hole 324 extends along a cross yoke axis ‘C’. In an exemplary embodiment, the cross yoke axis ‘C’ is spaced from the second longitudinal axis ‘L2’ and extends generally perpendicular to the second longitudinal axis ‘L2’.
In an exemplary embodiment, the blocking arm 344 may include a first section 345 and second section 346. The first section extends from the securing section 342 and the second section 346 extends from the first section 345 at least partially across the cross hole 324.
In addition, in the assembled condition, the notch 334 of the shaft 330 is aligned with the cross hole 324 of the yoke 320. Accordingly, the notch axis ‘N’ and the cross yoke axis ‘C’ are aligned so that the fastener (not shown) may be received through the cross hole 324 and the notch to secure the yoke 320, and thus, the intermediate shaft, to the shaft 330.
The blocking arm 344 is biased toward the first position. Thus, during insertion of the shaft 330 into the yoke bore 322, the shaft 330 is urged outward from the yoke bore 322. In addition, the blocking arm 344 of the biasing device 340 blocks the cross hole 324 of the yoke 320 when in the first position. Thus, a fastener may not be received in the cross hole 324 if the blocking arm 344 is not deflected to a position, i.e., the second position, clear of the cross hole 340.
The blocking arm 344 is in the second position when the shaft 330 reaches a position in the yoke bore 322 where the fastener may be inserted through cross hole 324. With the blocking arm 344 in the second position, the second section 346 is received within shaft bore 332. In this position, the blocking arm 344 may operate to retain the shaft 330 in the position where the fastener may be received in the cross hole 324. For example, with the blocking arm 344 at least partially received in the shaft bore 332, an end of the first section 345 and an end of the second section 346 may engage opposite sides of an inner wall of the shaft bore 322 to resist movement of the shaft 330 in an outward direction, i.e., a direction where the shaft 330 is removed from the yoke bore 322.
The shaft 330 may include a retaining slot 336 at an end that comes into contact with the biasing device 340. The biasing device 340 is dimensioned to extend completely across the cross hole 324 of the yoke 320. In an exemplary embodiment, the second section 346 of the blocking arm 344 extends completely across the cross hole 324 and is received within the retaining slot 336 of the shaft 330. Further, the blocking arm 344 may be partially received within the shaft bore 332. However, the second section 346 of the blocking arm 344 is dimensioned so that it is not completely received within the shaft bore 332 when the coupling assurance assembly is assembled.
In the exemplary embodiments above, the shaft and yoke are assembled in a male/female relationship. With reference to the embodiments shown in
In the exemplary embodiments above, a proper coupling between a yoke that is attached to an intermediate shaft of a steering column and a shaft may be ensured. The shaft may be, for example, an output, or steering shaft of steering column positioned at one of the intermediate shaft, or an input, or gear shaft of a steering gear positioned at an opposite end of the intermediate shaft. A biasing device is positioned between the yoke and the shaft so that one is urged away from the other unless a fastener is properly installed. Thus, during assembly, if a fastener is not installed one of the yoke and shaft is urged away from the other so that is a visible indication that the yoke and shaft are not coupled. In addition, the biasing device is configured to extend across a portion of the yoke or shaft configured to receive the fastener so as to prevent insertion of the fastener. With this feature, premature installation of the fastener may be avoided, as the biasing device is not moved to a position where the fastener may be received in the yoke and/or shaft until the yoke and shaft are properly positioned relative to one another. In addition, the biasing device may be used to remove or reduce lash, i.e., space between parts resulting from part-to-part variations, between the shaft and the yoke.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description.
