Patent Description:
Press-fit components, such as lab seals and shaft collars, utilize an interference or press fit between the inner diameter surface and an outer diameter surface of the mating components. Overtime, such press-fit components may need to be replaced or serviced. Non-destructive disassembly of the components can be challenging. There is, thus, a continued need for improved press-fit disassembly processes and tooling.

<CIT> relates to an extractor apparatus for extracting one element e.g. a bearing race from another element e.g. a motor car half back axle shaft or a motorcycle crank shaft.

It discloses the preamble of claim <NUM>.

According to an aspect of the invention, there is provided a tool for removing a seal from an engine component as claimed in claim <NUM>.

According to a further general aspect of the invention, there is provided a method of removing a press-fit seal from an engine component having a central axis as claimed in claim <NUM>.

Some embodiments of the invention are as claimed in the dependent claims.

As required, detailed embodiments of the present technology are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the technology, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present technology in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the technology.

The terms "a" or "an", as used herein, are defined as one or more than one. The term "plurality", as used herein, is defined as two or more than two. The term "another", as used herein, is defined as at least a second or more. The terms "including" and/or "having", as used herein, are defined as comprising (i.e., open language). The term "coupled", as used herein, is defined as connected, although not necessarily directly.

Many aircraft engine components, including bushings, bearings, shaft collars, rotors, and seals, are assembled with an interference fit (also know as press or friction fit). <FIG> illustrates an example of a press-fit assembly in the context of an aircraft engine. More particularly, <FIG> illustrates a turbine section <NUM> of an aircraft engine including a turbine disc <NUM> carrying a circumferential array of turbine blades <NUM>, the disc <NUM> mounted for rotation about a central axis (A). A labyrinth seal <NUM> (hereinafter referred to as a lab seal <NUM>) is press fit on a spigot <NUM> extending axially forwardly from a hub <NUM> of the turbine disc <NUM> to provide a rotational sealing interface between the rotating turbine disc <NUM> and an adjacent surrounding static runner surface of a structure <NUM> of the turbine section <NUM>. The seal inner diameter is press fit onto the spigot outer diameter. In other words, an interference fit is provided between an inner diameter (ID) surface 14a of the lab seal <NUM> and an outer diameter (OD) surface 16a of the spigot <NUM> of the turbine disc <NUM>.

Removal of such a press-fit lab seal <NUM> from the turbine disc <NUM> may be challenging. For instance, if the teeth of the lab seal <NUM> are worn down, there might not be a sufficient surface area for a puller tool to properly grab the lab seal <NUM> and axially pull the lab seal <NUM> out from the turbine disc <NUM>. In addition, the pulling action of the puller on the lab seal <NUM> may potentially damage the lab seal teeth. Furthermore, if the lab seal <NUM> or the pulling force on the lab seal <NUM> is not purely coaxial to the turbine disc axis, there is a risk of introducing residual stress into the disc <NUM> and/or the lab seal <NUM> while the lab seal <NUM> is being pulled out. How to efficiently achieve non-destructive disassembly for such press-fit components is, thus, a subject of concerns.

<FIG> illustrate an embodiment of a tool <NUM> for facilitating the separation of the lab seal <NUM> from the turbine disc <NUM>, while mitigating the risk of damaging the turbine disc <NUM> and the lab seal <NUM> during the disassembly process. As will be seen hereinafter, the tool <NUM> is configured to restrain or block the axial movement the lab seal <NUM> in a first axial direction F1 (downward direction in the example depicted in <FIG>) while a predetermined calibrated pushing force or press load is applied onto the disc <NUM> in the first axial direction to disengage the disc <NUM> from the lab seal <NUM>.

The tool <NUM> generally comprises a support <NUM> for holding the disc and lab seal assembly by the lab seal <NUM> and a pusher <NUM> for applying an axial force onto the disc <NUM> while the lab seal <NUM> is axially restrained by the support <NUM> from moving in the direction of the pushing force (i.e. axial direction F1). As best shown in <FIG>, the support <NUM> may be configured to support the disc and lab seal assembly in a vertical orientation. According to the illustrated embodiment, the support <NUM> is configured to hold the turbine disc <NUM> in suspension via the lab seal <NUM>.

According to one or more embodiments, the support <NUM> generally comprises a base <NUM> and shell halves 28a, 28b. The shell halves 28a, 28b are adapted to be pre-assembled onto the disc <NUM> around the lab seal <NUM>. As shown in <FIG>, the shell halves 28a, 28b are engageable around the lab seal <NUM> on the OD surface 16a of the spigot <NUM> of the turbine disc <NUM>. The shell halves 28a, 28b jointly define a central annular seat around a central bore when joined along their central split line. According to one or more embodiments, the central annular seat may be provided in the form of a counterbore <NUM> or the like centrally defined in the top surface of the shell halves 28a, 28b. As shown in <FIG>, the bottom annular wall 31a of the counterbore <NUM> offers an axial abutment or axial arresting surface for the lab seal <NUM> around the OD surface 16a of the spigot <NUM> of the disc <NUM>. The bottom annular wall 31a thus acts as an axial stopper for the lab seal <NUM>. The cylindrical wall 31b of the counterbore <NUM> is configured to surround the lab seal <NUM> when the lab seal <NUM> rests on the bottom wall 31a of the counterbore <NUM>. As shown in <FIG>, the counterbore <NUM> is sized to provide a radial gap or play between the distal end of the lab seal teeth 14b and the cylindrical wall 31b. As shown in <FIG> and <FIG>, the innermost diameter surface 31c of the adjoining shell halves 28a, 28b may have a contour that generally follows the profile of the disc <NUM> at the junction between the spigot <NUM> and the hub <NUM> of the turbine disc <NUM>. The innermost diameter surface 31c is sized and shaped to provide a play or gap between the shell halves 28a, 28b and the turbine disc <NUM>. This allows the lab seal and disc assembly to be axially supported solely from the lab seal on the support <NUM>. That is the lab seal and disc assembly is hung by the lab seal <NUM> on the support <NUM>. The shell halves 28a, 28b may be made of metal or another suitable high strength material. For instance, the shell halves 28a, 28b can be made out of alloy steel. As shown in <FIG>, axial holes <NUM> may extend thicknesswise through the shell halves 28a, 28b to increase their stiffness and reduce their weight.

As can be appreciated from <FIG> and <FIG>, the base <NUM> may be provided in the form of a cylindrical metal enclosure having a top-open end. The base <NUM> defines an open-ended interior chamber <NUM> sized to accommodate the turbine disc <NUM> in a vertical orientation. The shell halves 28a, 28b, when united around the lab seal <NUM> on the turbine disc <NUM>, form a disc-shaped lab seal capping structure, which seats in a corresponding cylindrical recess/seat <NUM> formed at the top end of the base <NUM>. From <FIG>, it can be appreciated that the cylindrical recess <NUM> has an annular bottom surface 32a against which the shell halves 28a, 28b rest. The joined shell halves 28a, 28b are, thus, uniformly supported along their outer circumference on top of the interior chamber <NUM> of the base <NUM>. Pins <NUM> or the like may be engaged with the base <NUM> and the shell halves 28a, 28b to ensure proper positioning of the shell halves 28a, 28b on the base <NUM> and to restrict angular movement therebetween around the central axis A. According to the illustrated embodiment, the pins <NUM> include a pair of diametrically opposed tubular pins. Each pin <NUM> is engaged in a mating hole 35a, 35b defined in the outer diameter surface of each of the shell halves 28a, 28b. The pins <NUM> extend outwardly from the shell halves 28a, 28b for engagement in corresponding semi-circular recesses <NUM> (<FIG>) defined at diametrically opposed locations in the top surface of the top circular lip <NUM> of the base <NUM>.

As shown in <FIG>, the interior surface of the base <NUM> may be lined with any proper padding or protective material to protect the disc <NUM> when pushed out from engagement with the lab seal by the pusher <NUM>. For instance, the bottom surface <NUM> of the interior chamber <NUM> may be lined with a rubber pad <NUM> or other suitable shock absorbing material. An adhesive may be provided between the rubber pad <NUM> and the bottom surface <NUM>. A central hole <NUM> may be defined through the rubber pad <NUM> and the bottom surface <NUM> to receive the lower end portion of the disc <NUM> when disengaged from the lab seal <NUM>. The cylindrical sidewall of the interior chamber <NUM> may also be lined with a protective sleeve <NUM>. The protective sleeve <NUM> may be made of a thermoplastic or other equivalent high impact strength materials. For instance, the protective sleeve <NUM> may be made out of High Density Polyethylene (HDPE).

Referring jointly to <FIG> and <FIG>, it can be seen that the support <NUM> further includes a cap <NUM> releasably securable to the base <NUM> on top of the shell halves 28a, 28b and the lab seal <NUM>. Mechanical fasteners, such as threaded fasteners <NUM>, may be used to releasably secure the cap <NUM> to the base <NUM>. According to the illustrated embodiment, the threaded fasteners <NUM> are provided in the form of knurled knobs with threaded shanks for threaded engagement with corresponding threaded holes defined in the top surface of the base <NUM>. According to the illustrated embodiment, the cap <NUM> extends longitudinally along the split line of the shell halves 28a, 28b. The attachment of the cap <NUM> over the shell haves 28a, 28b and the lab seal <NUM> prevents that lab seal <NUM> and the shell halves 28a, 28b from popping out of the base <NUM> when the turbine disc <NUM> is axially pushed downward into the interior chamber <NUM> of the base <NUM> by the pusher <NUM>. As shown in <FIG>, the cap <NUM> defines a central hole 42a in registry with the counterbore <NUM> in the top surface the shell halves 28a, 28b. The central hole 42a is sized to loosely accommodate the distal end portion of the disc spigot <NUM>. As can be appreciated from <FIG> and <FIG>, the distal end portion of the disc spigot <NUM> projects axially out of the central hole 42a of the cap <NUM> when the lab seal and disc assembly are installed in position on the base <NUM>. This allows the pusher <NUM> to be subsequently axially engaged with the disc <NUM>.

As shown in <FIG> and <FIG>, the cap <NUM> has a central hollow cylindrical projection 42b extending from a bottom surface thereof. The central hole 42a of the cap extends through the central cylindrical projection 42b. The central projection 42b is axially engageable in the upper portion of the counterbore <NUM> formed in the top surface the shell halves 28a, 28b. As shown in <FIG>, the length of the central projection 42b is selected to maintain a small axial gap between the upper end of the lab seal <NUM> and the central projection 42b of the cap <NUM> when the cap <NUM> is mounted to the base <NUM>. The central projection 42b acts as a stopper for preventing the lab seal <NUM> from popping out of the shell halves 28a, 28b when the disc <NUM> is pushed by the pusher <NUM> into the chamber <NUM> of the base <NUM>. Likewise, the cap lateral longitudinal side portions 42c that extend laterally from the central projection 42b over the top surface of the shell halves 28a, 28b acts as a stopper for preventing unintentional removal of the shell halves 28a, 28b from the top of the base <NUM>.

Still referring to <FIG>, it can be seen that the pusher <NUM> has a body including a central axially extending male portion 24a slidably axially engageable in a central bore 16b extending through the distal end portion of the disc spigot <NUM>. The engagement of the male portion 24a with the wall surface circumscribing the central bore 16b allows to properly axially align the pusher <NUM> with the central axis (A) of the turbine disc <NUM>. In this way, the disc <NUM> can be pushed in a substantially pure axial direction. The term "substantially" is herein intended to encompass slight angular variations that would not induce damage to the parts when the disc is pushed. For instance, a deviation of <NUM> degrees could be acceptable in some applications. It is also understood that other suitable aligning features could be used.

The body of the pusher <NUM> further has an annular shoulder 24b extending around the male portion 24a for axial abutment against a corresponding inner annular shoulder 16c of the disc spigot <NUM>. The axial engagement of the shoulders 16c and 24b allows to transfer an axially directed pushing force from the pusher <NUM> to the disc <NUM>.

As shown in <FIG>, the pusher <NUM> may also include a collar 24c to act as a stopper for limiting axial travel of the pusher <NUM> in the pushing direction F1 (vertically downward direction in the embodiment of <FIG>). The collar 24c can be provided as a separate annular part adapted to be mounted on a shoulder formed at an upper end portion of the body of the pusher <NUM>. According to one embodiment, the body of the pusher <NUM> can be made from a block of metal, such as alloy steel, and the collar 24c can be made of High Density Polyethylene. Suitable fasteners may be used to secure the collar 24c to the body of the pusher <NUM>. According to another embodiment, the collar 24c could be integrally formed with the body of the pusher <NUM>. The collar 24c is sized to overlap the top surface of the cap <NUM> to thereby physically limit the depth of insertion of the pusher <NUM> into the central hole 42a of the cap <NUM>.

According to one possible disassembly process, the turbine disc <NUM> is first removed from the turbine section <NUM>. Then, the turbine blades <NUM> are removed from the turbine disc <NUM>. To reduce the force required to remove the lab seal <NUM> and mitigate the risk of tool and/or disk damage, the lab seal <NUM> may be lubricated with a penetrating fluid (e.g. oil. Furthermore, the lab seal <NUM> may be heated with a heating device, such as a heat gun. According to one or more embodiments, the heating device is set up to <NUM> degrees Celsius for a minimum of <NUM> minutes to a maximum of <NUM> minutes, maintaining a <NUM>,<NUM> (<NUM> inch) to a <NUM>,<NUM> (<NUM> inch) gap between tip of the heat gun and the engine components. During the heating process, a relative circular motion between the heat gun and the lab seal <NUM> is provided to ensure uniform heating along the entire circumference of the lab seal <NUM>. The thermal treatment may also include cooling the turbine disc spigot.

After the thermal treatment, the shell halves 28a, 28b are pre-assembled onto the disc spigot <NUM> around the lab seal <NUM> so that the end surface of the lab seal <NUM> facing the hub <NUM> is axially abutted against the bottom wall 31a of the counterbore <NUM> formed in the top surface of the shell halves 28a, 28b. The lab seal and disc assembly is then installed in a vertical orientation on the base <NUM> by lowering the assembly so as to seat the shell halves 28a, 28b on the associated seat <NUM> on the base <NUM>, thereby hanging the turbine disc <NUM> by the lab seal <NUM>. As shown in <FIG>, at this stage of the procedure, the vertically oriented turbine disc <NUM> is held in suspension in the interior chamber <NUM> of the base <NUM>. Thereafter, the cap <NUM> is secured to the base <NUM> in position over the lab seal <NUM> and the shell halves 28a, 28b. The pusher <NUM> is then coaxially aligned with the turbine disc <NUM> by axially slidably engaging the male projection 24a of the pusher <NUM> into the bore 16b at the upper end of the disc spigot <NUM>. Then, a press (not shown), such as a hydraulic or pneumatic press is used to apply a pushing force to the top of the pusher <NUM> in the axial direction F1 (a vertically downward force according to the embodiment illustrated in <FIG>). According to one or more embodiment, the press may be of the arbor or H-frame type. Still according to one or more embodiments, the press force is set between <NUM>-<NUM> LBF (<NUM>-<NUM> N). The pushing force of the press is transferred to the turbine disc <NUM> by the pusher <NUM>. As the lab seal <NUM> is axially restrained by the bottom wall 31a of the counterbore <NUM> of the shell halves 28a, 28b, which are, in turn, seated at the top of the base <NUM>, the disc <NUM> will be pushed out of engagement from the lab seal <NUM>, which will remain trapped between the shell halves 28a, 28b. The disengaged disc will rest on the padding <NUM> on the bottom surface <NUM> of the chamber <NUM> of the base <NUM>.

It can thus be appreciated that according to at least some embodiments, the tooling mitigates the risk that the disc <NUM> and the lab seal <NUM> be damaged. It may thus allow the lab seal <NUM> to be reused if serviceable. Also, it may facilitate the removal of damaged lab seals with worn out teeth.

According to one embodiment shown in <FIG>, there is provided a method <NUM> for removing a press-fit seal from an engine component having a central axis. As indicated at <NUM>, the method <NUM> comprises restraining the press-fit seal from axially moving in a first axial direction. Then at <NUM>, the method <NUM> further comprises applying a pushing force on the engine component in the first axial direction. It is understood that, the first axial direction does not necessarily need to be vertical as exemplified in <FIG>.

The method <NUM> may entail positioning an abutment surface axially behind the press-fit seal relative to the first axial direction.

According to another aspect, the positioning of the abutment surface axially behind the press-fit seal may comprise assembling shell halves around the press-fit seal on the engine component, and then seating the shell halves in a corresponding seat at a top end of a base.

According to a further aspect, the method <NUM> may comprise hanging the engine component by the press-fit seal.

The method <NUM> may further comprise capturing the engine component in an enclosure formed by the base, the engine component held in a vertical orientation from a top end of the enclosure via the shell halves.

The method <NUM> may also include applying a heat treatment to at least one of the press-fit seal and the engine component prior to pushing the engine component.

Still according to one aspect of the method <NUM>, the pushing force is set between <NUM>-<NUM> LBF (<NUM>-<NUM> N).

<FIG> is a flow chart of another method <NUM> for removing a lab seal (e.g. lab seal <NUM>) from a turbine disc, the lab seal having an interference fit with a turbine disc. The method <NUM> comprises at <NUM> blocking the lab seal against axial movement in a first axial direction relative to the turbine disc. As indicated at <NUM>, the method <NUM> further comprises axially pushing the turbine disc out of engagement from the lab seal by applying a pushing force against the turbine disc in the first axial direction.

According to one or more embodiments, blocking the lab seal may comprise assembling shell halves around the lab seal and hanging the turbine disc via the shell halves. Still according to some embodiments, axially pushing the turbine disc out of engagement from the lab seal may comprise axially engaging a male portion of a pusher into a central bore extending through the turbine disc.

The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology as defined in the claims.

Claim 1:
A tool (<NUM>) for removing a seal (<NUM>) from an engine component (<NUM>), wherein an interference fit is provided between an inner diameter (ID) surface (14a) of the seal (<NUM>) and an outer diameter (OD) surface (16a) of the engine component (<NUM>), the ID surface (14a) and the OD surface (16a) extending circumferentially around a central axis (A), the tool (<NUM>) comprising:
a support (<NUM>) defining a first annular seat (<NUM>) offering an axial abutment for the seal (<NUM>) around the OD surface (16a) of the engine component (<NUM>), the axial abutment restraining axial movement of the seal (<NUM>) in a first axial direction (F1); and
a pusher (<NUM>) axially engageable with the engine component (<NUM>) to transfer a pushing force to the engine component (<NUM>) in the first axial direction (F1), wherein the support (<NUM>) comprises:
a base (<NUM>) defining an enclosure for receiving the engine component (<NUM>), and the first annular seat (<NUM>) is formed by shell halves (28a, 28b) engageable around the seal (<NUM>) on the OD surface (16a) of the engine component (<NUM>), the shell halves (28a, 28b) receivable in a second annular seat (<NUM>) surrounding a top open end of the enclosure; and
a cap (<NUM>) releasably securable to the base (<NUM>) over the shell halves (28a, 28b), the cap (<NUM>) defining a central hole (42a) in registry with a counterbore (<NUM>) formed in a top surface of the shell halves (28a, 28b), characterized in that the cap (<NUM>) has a central projection (42b) extending from a bottom surface thereof, the central projection (42b) of the cap (<NUM>) extending through the central hole (42a), the central projection (42b) engageable in the counterbore (<NUM>) formed in the top surface of the shell halves (28a, 28b).