Patent Description:
A gas turbine engine includes a compressor, a combustor, and a turbine which are lined up along a rotating shaft in a casing (see <CIT>, for example). The compressor includes: moving vanes connected to the rotating shaft; and variable stator vanes connected to the casing. A rotating shaft portion of the variable stator vane projects outside the casing. A unison ring is located at an outer periphery side of the casing. A pin in a pin hole of the unison ring is coupled to the rotating shaft portion of the variable stator vane through a lever. When the unison ring is rotated by an actuator along an outer peripheral surface of the casing by a desired angle, this rotation is transmitted through the lever to the rotating shaft portion of the variable stator vane, and this changes an angle of the variable stator vane.

<CIT> discloses a unison ring for a compressor, the unison ring being located along an outer periphery of the compressor casing, coupled to variable stator vanes of the compressor and comprising circular-arc bodies including fibre-reinforced material, with pin holes receiving a pin. A main orientation of the reinforced fibres of the fibre-reinforced material is directed in a circumferential direction of the unison ring. unison ring comprises curved ring segments each arranged between two adjacent bearing points, the curvature of the ring segments decreasing during an increase in the temperature of the ring segments so that the bearing points between the ring segments are displaced outwards in a radial direction. <CIT> discloses a gas turbine engine including a fan casing having body made from a composite material having at least one toughened region and at least one untoughened region, the toughened region containing a toughening agent selected from the group consisting of polymers, nano fibers, nano particles. In <CIT> a turbine vane adjustment assembly is disclosed including a vane stem that extends outwardly of a turbine case and further includes a motion converting sleeve in surrounding relationship thereto and coacting means between the sleeve and the vane stem that concurrently rotates both the sleeve and the stem and also provides relative axial movement of the sleeve with respect to the vane stem. The adjustment assembly further includes an actuator arm for rotating each of the vanes and means for connecting the actuator arm to the sleeve to cause angular positioning of the actuator arm to be directly transmitted to each of the vanes following calibration thereof. <CIT> discloses an adjusting ring for use with a compressor comprising a plurality of ring segments. Each ring segment has an outer element and an inner element connected to the outer element, the outer element has a first thermal expansion coefficient in the circumferential direction of the adjusting ring and the inner element has a second thermal expansion coefficient in the circumferential direction of the adjusting ring. In <CIT> a composite ring or segment of a ring for use as a shroud of an airplane engine is disclosed comprising about <NUM> to about <NUM> weight percent of the thermoplastic polymer and about <NUM> to about <NUM> weight percent of the carbon fibers. <CIT> discloses a device for the adjustment of stator vanes of a turbo engine including an adjusting ring and an adjusting lever. The adjusting lever includes a first end being connected to the adjusting ring and an end of a shank of the stator vane entering into an opening of a second end of the adjusting lever to connect the second end of the adjusting lever to the end of the shank of the stator vane. <CIT> discloses a compressor for a turbomachine with a stator comprising a casing and one stage of a variable-pitch stator vane positioned on its outside and moved by an actuator ring supported by the casing. The ring is connected to the vane by a link in order to actuate the vane simultaneously, whereby the casing includes a fixed coaxial rail projecting from an outside surface of the casing, and three circumferentially spaced-apart groups of wheels are constrained to move along the rail and each group of the wheels is coupled to the ring by a radial guidance arrangement. <CIT> discloses another variable vane assembly for a compressor having a plurality of vanes and a synchronizing ring.

When rotating the unison ring by the actuator, pressure received by the variable stator vane from compressed air in the compressor is applied as reaction force to the unison ring through the lever. Therefore, bending stress and torsional stress are generated in the unison ring, and this may deform the unison ring. When the unison ring is deformed, the angle of the variable stator vane deviates from a target angle. When there is an error in the angle of the variable stator vane, the operation of the compressor becomes unstable, and the deterioration of the efficiency of the compressor may occur.

An object of the present invention is to devise a unison ring to prevent deteriorations of operation stability and efficiency of a compressor of a gas turbine engine.

A unison ring according to the present invention comprises the features of claim <NUM>.

According to the above configuration, the bending rigidity of the unison ring can be improved while reducing the weight of the unison ring. On this account, the error of the angle of the variable stator vane can be reduced, and the deteriorations of the operation stability and efficiency of the compressor of the gas turbine engine can be prevented.

The present invention can improve the rigidity of the unison ring and prevent the deteriorations of the operation stability and efficiency of the compressor of the gas turbine engine.

Hereinafter, an embodiment will be described with reference to the drawings.

<FIG> is a schematic diagram showing a gas turbine according to the embodiment. As shown in <FIG>, a gas turbine engine <NUM> includes a casing <NUM>. The casing <NUM> houses a compressor <NUM>, a combustor <NUM>, and a turbine <NUM>. The compressor <NUM> and the turbine <NUM> are coupled to each other through a rotating shaft <NUM>. The compressor <NUM> rotates in association with the turbine <NUM> to compress air and supplies the compressed air to the combustor <NUM>. A combustion gas ejected from the combustor <NUM> rotates the turbine <NUM> and is discharged to an outside. The gas turbine engine <NUM> may be utilized as an aircraft engine.

The compressor <NUM> includes plural pairs of moving vane rows and stator vane rows. At least one of the stator vane rows of the compressor <NUM> includes variable stator vanes <NUM> (see <FIG>) lined up in a circumferential direction of the casing <NUM> such that angles of attack of the variable stator vanes <NUM> are adjustable. Unison rings <NUM> are externally fitted to the casing <NUM> so as to be lined up in an axial direction of the gas turbine engine <NUM>. The unison rings <NUM> are rotatable relative to an outer peripheral surface of the casing <NUM> in the circumferential direction. When the unison rings <NUM> are angularly displaced in the the circumferential direction (rotational direction) along the outer peripheral surface of the casing <NUM>, the angles of attack of the variable stator vanes <NUM> change.

<FIG> is a front view of the unison ring <NUM> of the gas turbine engine <NUM> shown in <FIG>. <FIG> is a sectional view taken along line IIA-IIA of <FIG>. <FIG> is a sectional view taken along line IIB-IIB of <FIG>. <FIG> is a partial perspective view of the unison ring <NUM> shown in <FIG>. As shown in <FIG>, the unison ring <NUM> is an annular body made of fiber-reinforced resin by integral molding. The unison ring <NUM> may include separate circular-arc bodies located circumferentially and have a practically annular shape as a whole.

An axis X of the unison ring <NUM> passes through a center of the unison ring <NUM> and is orthogonal to a radial direction R of the unison ring <NUM>. A direction (hereinafter referred to as an "axial direction X") in which the axis X of the unison ring <NUM> extends is a direction orthogonal to the radial direction R of the unison ring <NUM>. A circumferential direction C of the unison ring <NUM> is a direction along an outer peripheral surface of the unison ring <NUM>. To be specific, when viewed in the axial direction X, the circumferential direction C of the unison ring <NUM> is a direction along a circle whose center is the axis X of the unison ring <NUM>.

Regarding a section (section including the axis X of the unison ring <NUM>) of the unison ring <NUM> orthogonal to the circumferential direction C, the unison ring <NUM> may adopt various sectional shapes falling within the scope of claim <NUM>. As one example, the unison ring <NUM> includes an inner plate <NUM>, an outer plate <NUM>, a coupling plate <NUM>, a pair of inner flange plates <NUM>, and a pair of outer flange plates <NUM>. Each of the inner plate <NUM> and the outer plate <NUM> has a cylindrical shape including main surfaces facing the radial direction R. The outer plate <NUM> is located concentrically with the inner plate <NUM> and away from the inner plate <NUM> outward in the radial direction R. The inner plate <NUM> includes pin holes 21a located at intervals in the circumferential direction, and the outer plate <NUM> includes pin holes 22a located at intervals in the circumferential direction. The pin holes 21a of the inner plate <NUM> and the pin holes 22a of the outer plate <NUM> coincide with each other when viewed in the radial direction R.

The coupling plate <NUM> has an annular flat plate shape including main surfaces facing the axial direction X. The coupling plate <NUM> couples one end of the inner plate <NUM> in the axial direction X to one end of the outer plate <NUM> in the axial direction X. An intermediate space S between the inner plate <NUM> and the outer plate <NUM> is open toward a side in the axial direction X which is opposite to a side at which the coupling plate <NUM> is. In other words, the unison ring <NUM> includes an opening Q between the other end of the inner plate <NUM> in the axial direction X and the other end of the outer plate <NUM> in the axial direction X.

Each of the pair of inner flange plates <NUM> has an annular flat plate shape including main surfaces facing the axial direction X. The pair of inner flange plates <NUM> are located away from each other in the axial direction X. The pair of inner flange plates <NUM> project inward in the radial direction R from both ends of the inner plate <NUM> in the axial direction X, respectively. Each of the pair of outer flange plates <NUM> has an annular flat plate shape including main surfaces facing the axial direction X. The pair of outer flange plates <NUM> are located away from each other in the axial direction X. The pair of outer flange plates <NUM> project outward in the radial direction R from both ends of the outer plate <NUM> in the axial direction X, respectively.

Each of the pair of outer flange plates <NUM> includes a support 25a partially projecting in the radial direction R. The support 25a is integrally molded as a part of the outer flange plate <NUM>. The support 25a includes a support hole H penetrating in the axial direction X. The support 25a is a portion to which driving power of a below-described actuator <NUM> is input to angularly displace the unison ring <NUM> relative to the casing <NUM> around the axis X.

In the present embodiment, the section of the unison ring <NUM> orthogonal to the circumferential direction C has a π shape when the axial direction X is set to an upper-lower direction. The section of the unison ring <NUM> orthogonal to the circumferential direction C has such a shape that a dimension L1 of the unison ring <NUM> in the radial direction R is larger than a dimension L2 of the unison ring <NUM> in the axial direction X regardless of the position of the section in the circumferential direction C. To be specific, "L1 > L2" is satisfied in not only the section shown in <FIG> but also the section shown in <FIG>.

As described above, the unison ring <NUM> is made of fiber-reinforced resin containing resin and reinforcing fibers. The resin is a resin material selected from bismaleimide, epoxy, polyimide, and the like. The reinforcing fibers are fibrous materials selected from carbon fibers, glass fibers, aramid fibers, and the like. The unison ring <NUM> is manufactured by laminating prepregs and subjecting the prepregs to pressing. The prepregs are prepared by impregnating reinforcing fiber sheets with the resin.

The reinforcing fiber sheets include, for example, a sheet made of a UD material in which reinforcing fibers are oriented in one direction and a sheet made of a fabric material in which reinforcing fibers are oriented in two directions. The orientation of the UD material extends in the circumferential direction C of the unison ring <NUM>. One of the orientations of the fabric material extends in the circumferential direction C of the unison ring <NUM>. For example, a ratio of the reinforcing fibers extending in the circumferential direction C of the unison ring <NUM> to all the reinforcing fibers of the fabric material may be <NUM>% or more.

The most common orientations among all the orientations of the reinforcing fibers in the entire unison ring <NUM> extend in the circumferential direction C of the unison ring <NUM>. To be specific, a main orientation of the reinforcing fibers of the fiber-reinforced resin is directed in the circumferential direction C of the unison ring <NUM>.

The reinforcing fiber sheets include first reinforcing fiber sheets, second reinforcing fiber sheet, and third reinforcing fiber sheets. Two sheets among the first to third reinforcing fiber sheets are partially laminated on each other. In the section of the unison ring <NUM> orthogonal to the circumferential direction C, the first to third reinforcing fiber sheets are located so as to partially extend in different directions.

Therefore, there is a gap surrounded by the first to third reinforcing fiber sheets. A reinforcing fiber filler impregnated with the resin is in the gap. Therefore, the decrease in strength due to the gap is prevented. For example, a reinforcing fiber sheet rounded in a tubular shape may be used as the reinforcing fiber filler. It is preferable that the main orientation of the reinforcing fibers of the reinforcing fiber filler be directed in the circumferential direction C of the unison ring <NUM>.

<FIG> is a sectional view showing major components of the gas turbine engine <NUM> to which the unison ring <NUM> shown in <FIG> is applied. As shown in <FIG>, a pin <NUM> is in the pin holes 21a and 22a of the inner and outer plates <NUM> and <NUM> of the unison ring <NUM> in the radial direction R in a state where the pin <NUM> is prevented from coming out. The pin <NUM> is in a first end portion 14a of a lever <NUM> so as to be rotatable. The first end portion 14a of the lever <NUM> is in connection with the pin <NUM> in the intermediate space S of the unison ring <NUM> so as to be rotatable and extends through the opening Q of the unison ring <NUM> in the axial direction X to an outside of the intermediate space S.

The variable stator vane <NUM> includes a stator vane main body 11a and a shaft 11b. The stator vane main body 11a is a blade that contacts and rectifies a fluid in the compressor <NUM>. The shaft 11b projects from the stator vane main body 11a outward in the radial direction R to an outside of the casing <NUM>. A second end portion 14b of the lever <NUM> is fixed to the shaft 11b of the variable stator vane <NUM> by a fastener <NUM> so as not to be rotatable. A rotation axis Y of the variable stator vane <NUM> is an axis of the shaft 11b. When the first end portion 14a of the lever <NUM> is displaced in the circumferential direction C, the second end portion 14b of the lever <NUM> angularly displaces the variable stator vane <NUM> around the axis Y.

<FIG> is a diagram for explaining an operation trajectory T of the pin hole 22a of the unison ring <NUM> when the unison ring <NUM> and the like shown in <FIG> are viewed from an outside in the radial direction R. As shown in <FIG>, both end portions of a pin <NUM> are in the support holes H (also see <FIG>) of the pair of outer flange plates <NUM> in a state where the pin <NUM> is prevented from coming out. The pin <NUM> is in a tip portion of a rod <NUM> so as to be rotatable. The rod <NUM> is driven by the actuator <NUM> so as to advance or retreat in the circumferential direction C along the outer peripheral surface of the unison ring <NUM>. For simplicity, <FIG> shows that the actuator <NUM> is in direct connection with the rod <NUM>. However, as in <CIT>, a crank structure (not shown) and the like may be located between the actuator <NUM> and the rod <NUM>.

When the rod <NUM> advances or retreats by the driving power of the actuator <NUM>, the unison ring <NUM> is angularly displaced in the circumferential direction C around the axis X. With this, the pin <NUM> moves in the circumferential direction C, the lever <NUM> turns around the axis Y, and the variable stator vane <NUM> is angularly displaced around the axis Y. At this time, the driving power of the actuator <NUM> is input to the supports 25a of the unison ring <NUM>. Thus, a load is input to a part of the unison ring <NUM> in the circumferential direction C (<FIG> shows two load input portions (supports 25a)). Therefore, stress that causes bending deformation in the radial direction R is generated in the unison ring <NUM>.

Moreover, since the lever <NUM> has a fixed length, the pin <NUM> and the pin hole 22a move on the trajectory T having a circular-arc shape about the axis Y of the variable stator vane <NUM>. Therefore, in accordance with the advancing or retreating of the rod <NUM>, the unison ring <NUM> moves in the circumferential direction C and also moves slightly in the axial direction X. In this case, an advance-retreat direction of the rod <NUM> slightly deviates from the circumferential direction C of the unison ring <NUM>. Therefore, stress that causes torsional deformation around the circumferential direction C is generated in the unison ring <NUM>.

The sectional shape of the unison ring <NUM> is not limited to the above, and various sectional shapes may be adopted, falling within the scope of claim <NUM>. <FIG> is a sectional view of a unison ring <NUM> of Modified Example <NUM>. <FIG> is a sectional view of a unison ring <NUM> of Modified Example <NUM>. <FIG> is a sectional view of a unison ring <NUM> of Modified Example <NUM>, which is not part of the invention. The same reference signs are used for components common to the components of the unison ring <NUM>, and the repetition of the same explanation is avoided.

As shown in <FIG>, unlike the unison ring <NUM> shown in <FIG>, the unison ring <NUM> of Modified Example <NUM> does not include the opening Q that opens the intermediate space S between the inner plate <NUM> and the outer plate <NUM>. To be specific, in the unison ring <NUM>, one of the pair of coupling plates <NUM> couples one end of the inner plate <NUM> in the axial direction X to one end of the outer plate <NUM> in the axial direction X, and the other of the pair of coupling plates <NUM> couples the other end of the inner plate <NUM> in the axial direction X to the other end of the outer plate <NUM> in the axial direction X. Since the other components are the same as those of the unison ring <NUM>, explanations thereof are omitted.

As shown in <FIG>, the unison ring <NUM> of Modified Example <NUM> does not include the outer flange plates <NUM>. It is preferable that a dimension of the unison ring <NUM> in the radial direction R be larger than a dimension of the unison ring <NUM> in the axial direction X. Since the other components are the same as those of the unison ring <NUM>, explanations thereof are omitted.

As shown in <FIG>, the unison ring <NUM> of Modified Example <NUM>, not forming part of the invention, does not include the inner flange plates <NUM>. It is preferable that a dimension of the unison ring <NUM> in the radial direction R be larger than a dimension of the unison ring <NUM> in the axial direction X. Since the other components are the same as those of the unison ring <NUM>, explanations thereof are omitted.

Next, differences of bending rigidity and torsional rigidity between the unison rings having different sectional shapes will be discussed. Calculation results of bending rigidity values and torsional rigidity values of the unison rings having different sectional shapes were obtained by using computer simulation. In the present simulation, "Inspire" that is software produced by Altair Engineering was used. In the present simulation, conditions other than the sectional shape are set to be the same among the unison rings.

<FIG> is a graph showing the bending rigidity values of the unison rings having the respective sectional shapes. <FIG> is a graph showing the torsional rigidity values of the unison rings having the respective sectional shapes. The sectional shape of "Base" is a rectangular shape that is the sectional shape of a conventional unison ring. The sectional shape of "Case <NUM>" is an annular shape. The sectional shape of "Case <NUM>" is an I shape. The sectional shape of "Case <NUM>" is a horseshoe shape. The sectional shape of "Case <NUM>" is the sectional shape shown in <FIG>. The sectional shape of "Case <NUM>" is the sectional shape shown in <FIG>. The sectional shape of "Case <NUM>" is the sectional shape shown in <FIG>. The sectional shape of "Case <NUM>" is the sectional shape of <FIG>. Each of vertical axes of the graphs of <FIG> denotes a relative value based on a value of the sectional shape of Base.

It is clear from <FIG> that the bending rigidity of the unison ring in each of Cases <NUM> to <NUM> is superior to the bending rigidity of the unison ring in each of Base and Case <NUM>. Moreover, it is clear from <FIG> that the torsional rigidity of the unison ring in each of Base and Cases <NUM> to <NUM> is superior to the torsional rigidity of the unison ring in each of Cases <NUM> and <NUM>. Therefore, it is clear that both the bending rigidity and torsional rigidity of the unison ring in each of Cases <NUM> to <NUM> are superior.

According to the above configuration, the unison ring <NUM> includes the fiber-reinforced resin, and the main orientation of the reinforcing fibers is directed in the circumferential direction C of the unison ring <NUM>. Therefore, the bending rigidity of the unison ring <NUM> can be improved while reducing the weight of the unison ring <NUM>. On this account, the error of the angle of the variable stator vane <NUM> can be reduced, and the deteriorations of the operation stability and efficiency of the compressor <NUM> of the gas turbine engine <NUM> can be prevented.

Moreover, the section of the unison ring <NUM> orthogonal to the circumferential direction C has such a shape that the dimension L1 of the unison ring <NUM> in the radial direction R is larger than the dimension L2 of the unison ring <NUM> in the axial direction X. Therefore, the bending rigidity of the unison ring <NUM> in the radial direction R can be further improved.

Moreover, the torsional rigidity can be improved by the flange plate portions <NUM> and <NUM> while reducing the weight and improving the bending rigidity by the coupling plate <NUM>. Furthermore, the intermediate space S between the inner plate <NUM> and the outer plate <NUM> is open toward a side in the axial direction X which is opposite to a side at which the coupling plate <NUM> is. Therefore, the lever <NUM> coupled to the variable stator vane <NUM> can be connected to the pin <NUM> in the intermediate space S between the inner plate <NUM> and the outer plate <NUM>. Thus, the degree of freedom of the layout can be improved.

Moreover, the resin used in the unison ring <NUM> is selected from bismaleimide, epoxy, polyimide, and the like, and the reinforcing fibers used in the unison ring <NUM> are selected from carbon fibers, glass fibers, aramid fibers, and the like. Therefore, the unison ring <NUM> having high specific strength and high heat resistance can be realized.

Claim 1:
A unison ring (<NUM>, <NUM>, <NUM>) for a gas turbine engine (<NUM>) including a compressor (<NUM>), a combustor (<NUM>), and a turbine (<NUM>), and for being located along an outer periphery of a casing (<NUM>) of the gas turbine engine (<NUM>) and coupled to variable stator vanes (<NUM>) of the compressor (<NUM>),
the unison ring (<NUM>, <NUM>, <NUM>) comprising:
an annular body including fiber-reinforced resin or circular-arc bodies including the fiber-reinforced resin, the fiber-reinforced resin including resin and reinforcing fibers; and
pin holes (21a, 22a) in which a pin (<NUM>) is received in a radial direction orthogonal to an axial direction of the unison ring (<NUM>, <NUM>, <NUM>), whereby
a main orientation of the reinforcing fibers of the fiber-reinforced resin is directed in a circumferential direction of the unison ring (<NUM>, <NUM>, <NUM>);
the unison ring (<NUM>, <NUM>, <NUM>) further comprising:
an inner plate (<NUM>) including a first pin hole of the pin holes (21a, 21b) and main surfaces facing the radial direction,
an outer plate (<NUM>) including a second pin hole of the pin holes (21a, 21b) and main surfaces facing the radial direction, the inner plate (<NUM>) and the outer plate (<NUM>) being located concentrically,
a coupling plate (<NUM>) including main surfaces facing the axial direction, the coupling plate (<NUM>) coupling the inner plate (<NUM>) to the outer plate (<NUM>), and
at least one flange plate portion including main surfaces facing the axial direction, the at least one flange plate portion projecting in the radial direction from at least one of an end of the inner plate (<NUM>) in the axial direction or an end of the outer plate (<NUM>) in the axial direction; and
the at least one flange plate portion comprising a pair of inner flange plates (<NUM>) projecting inward in the radial direction from both ends of the inner plate (<NUM>) in the axial direction.