Patent Description:
Bushings are often used as bearings to support a shaft that may rotate and/or slide relative to, for example, a fixed support. Typically, the bushing is fixedly secured to the fixed support. A clearance exists between the bushing and the shaft. The clearance allows for installation of the shaft, installation of the busing, as well as accommodates dimensional changes in the bushing due to operational temperatures and/or wear. Tight clearance is needed to mitigate risks of potential leaking between opposite ends of bushings. On the other hand, a clearance that is too tight makes installation difficult.

To reduce installation challenges, in some cases, the bushing may include a split through the entire length of the bushing. The split allows for a measure of compliance during installation along with maintenance of desired clearances. However, the split may introduce an unwanted leakage path beyond that provided by the closely controlled clearances. In other words, any installation improvements are offset by a higher risk of leaking.

<CIT> discloses a rack and pinion steering gear assembly including a housing and a rack, with a bushing in between having axially extending recesses enhance the flexibility of the bushing.

<CIT> discloses a slide bearing having a main body around a shaft body, and an elastic ring on the main body. The elastic ring comprises slits running axially from end towards another end.

<CIT> discloses a rack bush for vehicle steering apparatus having a bush body with an outer surface in contact with an inner surface of a rack housing and an inner surface that is in contact with a rack bar, the bush body having slits arranged circumferentially to absorb impact between the bar and body.

<CIT> discloses a rack bushing supported by an annular elastic member in a housing having a bushing body and a flange portion extending radially, the bushing body having a second axial slit extending from a second axial end to a middle portion in an axial direction.

<CIT> discloses an expandable rack bushing having a tubular portion with front slots and rear slots, with an axial overlap between the front and rear slots permits expansion and retraction of the tubular portion.

<CIT> discloses a cylindrical journal bearing bush having a bearing surface having a plurality of lubrication grooves defining first and second groove sets, each groove including a segment angular to the direction of rotation so that that lubricant is distributed both circumferentially and axially on the surface.

According to an aspect of the invention a leak resistant compliant bushing as claimed in claim <NUM> is disclosed.

Additionally, or alternatively, in this or other non-limiting examples, each of the first plurality of channels includes a first side portion and a second side portion that join at the terminal end portion; and each of the second plurality of channels includes a first side section and a second side section that join at the terminal end section.

Additionally, or alternatively, in this or other non-limiting examples, the terminal end portion includes a curvilinear portion.

Additionally, or alternatively, in this or other non-limiting examples, the first side portion includes a first segment a second segment, and the second side portion includes a third segment and a fourth segment, wherein the first segment and the third segment extend at the first angle relative to the axial axis.

Additionally, or alternatively, in this or other non-limiting examples, the second segment and the fourth segment extend at a non-zero angle relative to the axial axis.

Additionally, or alternatively, in this or other non-limiting examples, the first side section includes a first segment section and a second segment section, and the second side section includes a third segment section and a fourth segment section.

Additionally, or alternatively, in this or other non-limiting examples, the first segment is spaced from the second segment at a first width, and the third segment is spaced from the fourth segment at a second width, and the first segment section is spaced from the second segment section at a third width and the third segment section is spaced from the fourth segment section at a fourth width.

Additionally, or alternatively, in this or other non-limiting examples, the second width is non-uniform along the axial axis.

Additionally, or alternatively, in this or other non-limiting examples, the first width, the second width of each of the first plurality of channels and each of the third width and the fourth width of each of the second plurality of channels are substantially constant along a hoop direction of the bushing.

Additionally, or alternatively, in this or other non-limiting examples, the second width of each of the first plurality of channels and the fourth width of each of the second plurality of channels are non-uniform along the hoop direction.

According to a further aspect of the invention an aircraft as claimed in claim <NUM> is disclosed.

Additionally, or alternatively, in this or other non-limiting examples, the first side portion includes a first segment and a second segment, and the second side portion includes a third segment and a fourth segment, wherein the first segment and the third segment extend at the first angle relative to the axial axis.

Additionally, or alternatively, in this or other non-limiting examples, the first side section includes a first segment section and a second segment section, and the second side section includes a third segment section and a fourth segment section, the first segment is spaced from the second segment a first width, and the third segment is spaced from the fourth segment a second width, and the first segment section is spaced from the second segment section a third width and the third segment section is spaced from the fourth segment section a fourth width. The second width is non-uniform along the axial axis, the first width and the third width are substantially constant along a hoop direction of the bushing, and the second width and the fourth width are non-uniform along the hoop direction.

An aircraft in accordance with a non-limiting example is indicated generally at <NUM> in <FIG>. Aircraft <NUM> includes a fuselage <NUM> supporting a pair of wings, one of which is shown at <NUM>, and a tail <NUM>. Fuselage <NUM> defines, in part, a cabin <NUM> that accommodates crew and/or passengers. Wing <NUM> supports a first engine <NUM> and a second engine <NUM>. Fuselage <NUM> includes a cabin air system <NUM> that is connected to first engine <NUM>. Cabin air system <NUM> may also be connected to second engine <NUM>.

In a non-limiting example, cabin air system <NUM> includes an air intake <NUM> at first engine <NUM>, an air conditioner <NUM>, and an air mixing unit <NUM>. An air filter <NUM> filters air passing into an air circulation circuit <NUM>. An exhaust <NUM> discharges air from air circulation circuit <NUM> adjacent to tail <NUM>. A mechanical system, shown in the form of a bleed air valve <NUM> provides an interface between first engine <NUM> and air conditioner <NUM>.

In a non-limiting example shown in <FIG>, bleed air valve <NUM> includes a housing <NUM> including an inlet <NUM> and an outlet <NUM>. A controlling air inlet <NUM> projects outwardly from <NUM> between inlet <NUM> and outlet <NUM>. A valve member <NUM> is disposed in housing <NUM>. Valve member <NUM> selectively connected inlet <NUM> and outlet <NUM>. Valve member <NUM> includes a hub <NUM> supported on a shaft <NUM> having a shaft axis "A". A first leak resistant compliant bushing <NUM> and a second leak resistant compliant bushing <NUM> provide a wear resistant interface between hub <NUM> and shaft <NUM>. Openings <NUM> on shaft <NUM> are provided to fluidly connect controlling air with the interior of valve member <NUM> which provides an axial driving force. In a non-limiting example, valve member <NUM> transitions on shaft <NUM> along the shaft axis "A" when controlled by the pressure from <NUM> (passing through holes <NUM>) to fluidically connect air passing from first engine <NUM> through air inlet <NUM> to valve outlet <NUM>.

Reference will now follow to <FIG> in describing leak resistant compliant bushing <NUM>, that does not fall within the scope of the claims, with an understanding that leak resistant compliant bushing <NUM>, shown in <FIG>, may include similar structure. Leak resistant compliant bushing <NUM> includes a body <NUM> having a first end <NUM> and a second end <NUM>. In a non-limiting example, body <NUM> is formed from a metal or metal alloy. In additional embodiments, body <NUM> may also be formed from polymeric, fiber-reinforced polymer-matrix composites or hybrid (e.g., metallic/polymeric or metallic/composite) materials. An outer surface <NUM> extends between first end <NUM> and second end <NUM>. Likewise, an inner surface <NUM> extends between first end <NUM> and second end <NUM>. An axial axis "B" extends between first end <NUM> and second end <NUM>. A hoop axis "C" defining a hoop direction circumscribes outer surface <NUM>.

In a non-limiting example, a first plurality of channels <NUM> extends from first end <NUM> towards second end <NUM>. A second plurality of through-thickness channels <NUM> extends from second end <NUM> towards first end <NUM>. In a non-limiting example, each of the first plurality of channels <NUM> terminates short of second end <NUM> at a terminal end <NUM>. Each of the second plurality of channels <NUM> terminates short of first end <NUM> at a terminal end section <NUM>. In further accordance with a non-limiting example, each of the first plurality of channels <NUM> and second plurality of channels <NUM> extend entirely through body <NUM> (e.g., from outer surface <NUM> through inner surface <NUM>).

Reference will now follow to <FIG> in describing first and second pluralities of channels <NUM> and <NUM> in accordance with an example that does not fall within the scope of the claims. Each of the first plurality of channels <NUM> includes a first side portion <NUM> and a second side portion <NUM> that extend from first end <NUM> and converge at terminal end <NUM>. Each of the second plurality of channels <NUM> includes a first side section <NUM> and a second side section <NUM> that extend from second end <NUM> and converge at terminal end portion <NUM>.

In a non-limiting example, first side portion <NUM> includes a first segment <NUM> that extends substantially parallel to axial axis "B" and a second segment <NUM> that extends at an angle relative to axial axis "B". Similarly, second side portion <NUM> includes a third segment <NUM> that extends substantially parallel to axial axis "B" and a fourth segment <NUM> that extends at an angle relative to axial axis "B". First side section <NUM> includes a first segment section <NUM> that extends substantially parallel to axial axis "B" and a second segment section <NUM> that extends at an angle relative to axial axis "B". Similarly, second side section <NUM> includes a first segment section <NUM> that extends substantially parallel to axial axis "B" and a fourth segment section <NUM> that extends at an angle relative to axial axis "B". First and second pluralities of channels <NUM> and <NUM> allow body <NUM> to have a circumferential stiffness that is lower than a corresponding solid bushing of the same material, such that the bushing is easier to install reducing tooling required and cost. Further, unlike split bushings, channels <NUM> and <NUM> do not extend fully from end <NUM> to <NUM> thus leakage is equivalent to a solid bushing, and less than a split bushing.

Reference will follow to <FIG>, wherein like reference numbers represent corresponding parts in the respective views, in describing leak resistant compliant bushing <NUM> in accordance with another example that does not fall within the scope of the claims. As shown in <FIG>, first segment <NUM> and second segment <NUM> extend into body <NUM> along axes that are substantially parallel to axial axis "B". Likewise, third segment <NUM> and fourth segment <NUM> extend into body <NUM> along axes that are substantially parallel to axis "B".

Second segment <NUM> and fourth segment <NUM> join at terminal end <NUM> having a substantially curvilinear profile. First segment section <NUM> and second segment section <NUM> extend into body <NUM> along axes that are substantially parallel to axial axis "B". Likewise, first segment section <NUM> and fourth segment section <NUM> extend into body <NUM> along axes that are substantially parallel to axial axis "B". Second segment section <NUM> and fourth segment section <NUM> join at terminal end <NUM> having a substantially curvilinear profile.

Reference will follow to <FIG>, wherein like reference numbers represent corresponding parts in the respective views, in describing leak resistant compliant bushing <NUM> in accordance with yet another example that does not fall within the scope of the claims. First side portion <NUM> includes a first segment <NUM>, a second segment <NUM>, and a third segment <NUM>. First segment <NUM> extends substantially parallel to axial axis "B" while second segment <NUM> and third segment <NUM> extend at different angles relative to axial axis "B". Second side portion <NUM> includes a fourth segment <NUM>, a fifth segment <NUM>, and a sixth segment <NUM>. Fourth segment <NUM> extends substantially parallel to axial axis "B" while fifth segment <NUM> and sixth segment <NUM> extend at different angles relative to axial axis "B". In a non-limiting example, portions of the first plurality of channels <NUM> and/or portions of the second plurality of channels <NUM> can be defined with varied non-zero angles with respect to axial axis "A", creating for example, non-linear convex or concave profiles.

First side section <NUM> includes a first segment section <NUM>, a second segment section <NUM>, and a third segment section <NUM>. First segment section <NUM> extends substantially parallel to axial axis "B" while second segment section <NUM> and third segment section <NUM> extend at different angles relative to axial axis "B". Second side section <NUM> includes a fourth segment section <NUM>, a fifth segment section <NUM>, and a sixth segment section <NUM>. Fourth segment section <NUM> extends substantially parallel to axial axis "B" while fifth section <NUM> and sixth segment section <NUM> extend at different angles relative to axial axis "B". With this arrangement, the particular shape of first and second pluralities of channels <NUM> and <NUM> allows designers to tailor circumferential stiffness and thermal response of leak resistant compliant bushing <NUM> to specific operating conditions.

Reference will follow to <FIG>, wherein like reference numbers represent corresponding parts in the respective views, in describing leak resistant compliant bushing <NUM> in accordance with still yet another example that does not fall within the scope of the claims. First side portion <NUM> and second side portion <NUM> of each of the first plurality of channels <NUM> extend substantially parallel to one another and to axial axis "B". In a non-limiting example, first side portion <NUM> and second side portion <NUM> join at a curvilinear portion <NUM> defined by terminal end <NUM>. Similarly, first side section <NUM> and second side section <NUM> extend substantially parallel to one another and to axial axis "B". In a non-limiting example, first side section <NUM> and second side section <NUM> join at a curvilinear portion <NUM> defined by terminal end section <NUM>. Curvilinear portion <NUM> can be defined by either a constant or a varied radius.

In <FIG>, first side portion <NUM> and second side portion <NUM> of each of the first plurality of channels <NUM> extend substantially parallel to one another and to at a constant angle relative to axial axis "B". Likewise, first side section <NUM> and second side section <NUM> extend substantially parallel to one another and at a constant angle relative to axial axis "B". In <FIG> first side portion <NUM> and second side portion <NUM> of each of the first plurality of channels <NUM> extend substantially parallel to one another and to at a varying angle relative to axial axis "B". Likewise, first side section <NUM> and second side section <NUM> extend substantially parallel to one another and at a varying angle relative to axial axis "B". The arrangements depicted in FGS. <NUM>-<NUM> allow first and second pluralities of channels <NUM> and <NUM> to be formed with conventional machining processes using, for example, a rotary bit. In accordance with other non-limiting examples, individual ones of the first plurality of channels <NUM> and/or the second plurality of channels <NUM> may be sized to possess the same (e.g., uniform sizing and positioning of the channels) or different (e.g., non-uniform sizing and/or positioning of individual channels).

Reference will now follow to <FIG>, wherein like reference numbers represent corresponding parts in the respective views and where these examples do not fall within the scope of the claims. In accordance with a non-limiting example, first segment <NUM> is spaced from third segment <NUM> of each of the first plurality of channels <NUM> a first width "D1". Second segment <NUM> is spaced from fourth segment <NUM> of each of the first plurality of channels <NUM> a second width "D2" that varies along the axial axis "A". First segment section <NUM> is spaced from third segment section <NUM> of each of the second plurality of channels <NUM> a third width D3". Second segment section <NUM> is spaced from fourth segment section <NUM> of each of the second plurality of channels a fourth width "D4". In accordance with a non-limiting example, the first width "D1" and the third width "D3" are substantially uniform (e.g., constant along hoop direction "C" as shown in <FIG> and the second width "D2" and fourth width "D4" are non-uniform (e.g., not constant) along the hoop direction "C" as shown in <FIG>. In other embodiments, other more complex relationships between mutual sizing of variables D1, D2, D3 and D4 can be defined according to structural optimization of bushings, performed for example by the Finite Element Method.

At this point, it should be understood that the non-limiting examples shown and described herein represent various channel geometries that promote compliance in an annular bushing without introducing a leak path such as would be created by a split. Different channel geometries create varying degrees of compliance that may accommodate a wide range of operating conditions and installation methods. Further, while described as being formed from metal or metal alloy, other materials, particularly thermally responsive materials may also be employed. Additionally, while shown as having a substantially circular cross-section, the leak resistant compliant bushing may take on a wide range of shapes, including circular, as shown in <FIG>, and non-circular cross-sections, as shown in <FIG>, as well as a wide range of sizes. Examples of non-circular cross-sections can include, among others, quadratic, and rectangular shapes (<FIG>), polygonal shapes with different number of sides, e.g., triangular, pentangular, hexagonal (as illustrated in <FIG>) shapes, elliptical shapes, or other multi-segment shapes combining linear and/or curved profiles in different segments.

Claim 1:
A leak resistant compliant bushing (<NUM>) comprising:
a body (<NUM>) having a first end (<NUM>), a second end (<NUM>), an outer surface (<NUM>) and an inner surface (<NUM>) defining a passage, the outer surface (<NUM>) and the inner surface (<NUM>) extending between the first end (<NUM>) and the second end (<NUM>) and defining an axial axis (B);
a first plurality of channels (<NUM>) extending into the body (<NUM>) from the first end (<NUM>), each of the first plurality of channels (<NUM>) including a terminal end (<NUM>) that is spaced from the second end (<NUM>), each of the first plurality of channels (<NUM>) including a first central axis that extends from the first end (<NUM>) through the terminal end (<NUM>); and
a second plurality of through-thickness channels (<NUM>) extending into the body (<NUM>) from the second end (<NUM>), each of the second plurality of channels (<NUM>) extending between adjacent ones of the first plurality of channels (<NUM>) and including a terminal end section (<NUM>) that is spaced from the first end (<NUM>) , each of the second plurality of channels (<NUM>) including a second central axis that extends from the second end (<NUM>) through the terminal end (<NUM>), characterised in that each of the first central axis and the second central axis extends across the body (<NUM>) at a non-zero angle relative to the axial axis (B).