Patent Description:
The high lift assembly, which might be a leading edge high lift assembly or a trailing edge high lift assembly, comprises a high lift body, and a connection assembly for movably connecting the high lift body to the main wing, such that the high lift body can be moved relative to the main wing between a retracted position and at least one extended position. The high lift body is preferably formed as a slat or a droop nose in case of a leading edge high lift assembly and is preferably formed as a flap in case of a trailing edge high lift assembly.

The connection assembly comprises a drive system that is provided at, preferably fixedly mounted to, the main wing and that is connected to, preferably indirectly connected to, the high lift body for driving, i.e. initiating movement, of the high lift body between the retracted position and the extended position. The drive system comprises a first drive unit and a second drive unit spaced apart from one another in a wing span direction. The first drive unit is preferably formed as a geared rotary actuator (GRA) and has a first input section coupled to a drive shaft, a first gear unit, and a first output section drivingly coupled to the high lift body. The second drive unit is preferably formed as a geared rotary actuator (GRA) and has a second input section coupled to the drive shaft, a second gear unit, and a second output section drivingly coupled to the high lift body. The first and second gear units preferably transform high rotational speed with low torque from the first and second input sections, i.e. from the drive shaft, into low rotational speed with high torque at the first and second output sections.

The first output section comprises a rotatable first drive arm and the second output section comprises a rotatable second drive arm. The first drive arm is drivingly coupled to the high lift body via at least one first link element, preferably in the form of a drive strut, rotatably coupled to the first drive arm and rotatably mounted to the high lift body. The second drive arm is drivingly coupled to the high lift body via at least one second link element, preferably in the form of a drive strut, rotatably coupled to the second drive arm and rotatably mounted to the high lift body.

Such wings are known in the art. For the wings known in the art, skew cases are possible, where the first and second drive units do not move in sync and the high lift body might be skewed about a vertical axis. If one of the first and second drive units is blocked or moves slower than the other, e.g. due to failure, the other one of the first and second drive units might be transferring high actuating loads to the high lift body while skewed.

<CIT> discloses a transmission device for a trailing edge high lift actuation system of an aircraft which has a non-linear force-displacement characteristic with respect to translational movement. <CIT> discloses a leading edge high lift actuation system for an aircraft.

The object of the present invention is to prevent excessively high actuating loads during such skew cases of the high lift body. Claim <NUM> defines a high lift assembly for a wing in accordance with the present invention.

The object of the invention is achieved in that the first link element comprises a first linear deformation element. Additionally or alternatively, the second link element comprises a second linear deformation element. The first linear deformation element and/or the second linear deformation element have a non-linear force-displacement characteristic. By such first and second linear deformation elements the force-displacement characteristic can be adapted such that actuating loads occurring during skew cases of the high lift body can be limited in an efficient way. Preferably, at a maximum displacement, i.e. at a maximum skew of the high lift body, the corresponding load transferred from the first or second drive unit to the high lift body is lower than in case of a linear force-displacement characteristic. Also, sizing loads for the high lift assembly can be essentially reduced. The first linear deformation element and/or the second linear deformation element is formed as or comprises a spring element having a non-linear degressive stiffness.

According to a preferred embodiment, the force-displacement characteristic of the first linear deformation element and/or of the second linear deformation element has a higher slope at lower forces, preferably below a predetermined threshold force, and has a lower slope at higher forces, preferably above the threshold force. In such a way, the maximum actuating load occurring during skew of the high lift body can be efficiently reduced.

According to another preferred embodiment, the force-displacement characteristic of the first linear deformation element and/or of the second linear deformation element is linear, i.e. has a constant first slope, for forces below a threshold force. For forces above the threshold force the force-displacement characteristic of the first linear deformation element and/or of the second linear deformation element is non-linear, i.e. has at least one second slope different from the first slope. However, this does not mean that there necessarily needs to be a kink at the threshold force. Rather, the transition from the first slope to the second slope might be smooth and continuous. In such a way, the maximum actuating load occurring during skew of the high lift body can be efficiently reduced.

In particular, it is preferred that the threshold force is between <NUM>% and <NUM>%, preferably between <NUM>% and <NUM>%, most preferred at about <NUM>%, of the maximum force occurring during normal operation when both the first drive unit and the second drive unit are intact. Preferably, the first slope is at least <NUM> times higher, preferably at least <NUM> times higher, further preferred at least <NUM> times higher, yet further preferred at least <NUM> times higher, most preferred at least <NUM> times higher than the second slope. In such a way, above the threshold force there is only very little further increase in force with increasing displacement. However, the second slope might also be zero or might be negative, so that the force is constant or is decreasing after the threshold is reached. Also, it is possible that there is a third slope after the second slope which might be positive, negative, or zero.

According to a preferred embodiment, the first linear deformation element and/or the second linear deformation element have a non-linear force-displacement characteristic with respect to forces applied to extend the high lift body, i.e. to move the high lift body from the retracted position to the extended position. At the same time, the first linear deformation element and/or the second linear deformation element have a linear, preferably entirely linear, force-displacement characteristic with respect to forces applied to retract the high lift body, i.e. to move the high lift body from the extended position to the retracted position. Such a force-displacement characteristic is particularly advantageous for leading edge high lift assemblies.

According to an alternative embodiment, the first linear deformation element and/or the second linear deformation element have a non-linear force-displacement characteristic with respect to both forces applied to extend the high lift body and forces applied to retract the high lift body. Such a force-displacement characteristic is particularly advantageous for trailing edge high lift assemblies.

Preferably, the form, function, and/or material of first linear deformation element and/or second linear deformation element is adapted to realize the non-linear force-displacement characteristic, by the non-linear degressive stiffness. This can be done in various ways.

In particular, it is preferred that the spring element has an adjustable or controllable stiffness. In such a way, the stiffness can be adjusted or controlled to have a non-linear degressive behaviour.

It is particularly preferred that the spring element is formed as a pneumatic spring or a hydro-pneumatic spring, preferably as a gas pressure spring. By such a spring element a non-linear force-displacement characteristic, in particular, a non-linear degressive stiffness can be efficiently realized.

According to a preferred embodiment, the non-linear force-displacement characteristic of the first linear deformation element and/or the second linear deformation element is due to elastic deformation only. , two elastically deformed components are provided which are both loaded below the threshold force while only one of which is loaded when loads increase above the threshold force. Alternatively, the non-linear force-displacement characteristic of the first linear deformation element and/or the second linear deformation element is due to a combination of elastic deformation and plastic deformation. , only elastic deformation is present below the threshold force and plastic deformation alone or combined with elastic deformation is present when loads increase above the threshold force.

According to a further preferred embodiment, the high lift assembly is a leading edge high lift assembly and the high lift body is a leading edge high lift body, such as a slat or a droop nose. The non-linear force-displacement characteristic of the first linear deformation element and/or the second linear deformation element is particularly advantageous at the leading edge.

According to an alternative embodiment, the high lift assembly is a trailing edge high lift assembly and the high lift body is a trailing edge high lift body, such as a flap, which might be driven e.g. by a ball-screw actuator. The non-linear force-displacement characteristic of the first linear deformation element and/or the second linear deformation element is also advantageous at the trailing edge.

According to a further preferred embodiment, the connection assembly comprises a first connection element and a second connection element for guiding the high lift body when moved between the retracted and extended positions. The first connection element is movably mounted to the main wing and is mounted, preferably fixedly and/or directly mounted, to the high lift body. The second connection element is movably mounted to the main wing and is mounted, preferably fixedly and/or directly mounted, to the high lift body in a position spaced apart from the first connection element in the wing span direction.

According to a preferred embodiment, the first connection element is formed as a first track that is movably guided at the main wing and that is preferably fixedly mounted to the high lift body. Additionally or alternatively, the second connection element is formed as a second track that is movably guided at the main wing and that is preferably fixedly mounted to the high lift body. The first track and/or the second track are preferably in the form of an elongate support beam that is movable along the direction of its elongate extension, such as a slat track. Such first and second slat tracks can provide additional guidance of the high lift body.

According to an alternative preferred embodiment, the first connection element is formed as a first linkage, preferably comprising at least two link elements rotatably coupled to one another and rotatably coupled to both the main wing and the high lift body, preferably in the form of a four-bar linkage. Additionally or alternatively, the second connection element is formed as a second linkage, preferably comprising at least two link elements rotatably coupled to one another and rotatably coupled to both the main wing and the high lift body, preferably in the form of a four-bar linkage. Such first and second linkages can provide additional guidance of the high lift body.

According to a further preferred embodiment, the connection assembly comprises one or more further connection elements in the form of a track or in the form of a linkage. Preferably, the connection assembly comprises two further connection elements that are non-driven. Such further connection elements may provide further guidance of the high lift body.

A further aspect of the present invention relates to a high lift assembly for the wing according to any of the afore-described embodiments. The high lift assembly comprises a high lift body and a connection assembly for movably connecting the high lift body to a main wing, such that the high lift body can be moved between a retracted position and at least one extended position. The connection assembly comprises a drive system that is configured to be mounted to the main wing and that is connected to the high lift body for driving the high lift body between the retracted position and the extended position. The drive system comprises a first drive unit and a second drive unit spaced apart from one another in a wing span direction. The first drive unit has a first input section coupled to a drive shaft, a first gear unit and a first output section drivingly coupled to the high lift body. The second drive unit has a second input section coupled to the drive shaft, a second gear unit, and a second output section drivingly coupled to the high lift body. The first output section comprises a first drive arm and the second output section comprises a second drive arm. The first drive arm is drivingly coupled to the high lift body via at least one first link element rotatably coupled to the first drive arm and mounted to the high lift body. The second drive arm is drivingly coupled to the high lift body via at least one second link element rotatably coupled to the second drive arm and mounted to the high lift body. The first link element comprises a first linear deformation element, and/or the second link element comprises a second linear deformation element. The first linear deformation element and/or the second linear deformation element have a non-linear force-displacement characteristic. Features and effects explained further above in connection with the wing apply vis-à-vis also in case of the high lift assembly.

A further aspect of the present invention relates to an aircraft comprising a wing according to any of the afore-described embodiments and/or comprising a high lift assembly according to any of the afore-described embodiments. Features and effects explained further above in connection with the wing and with the high lift assembly apply vis-à-vis also in case of the aircraft.

Hereinafter, a preferred embodiment of the present invention is described in more detail by means of a drawing. The drawing shows in.

In <FIG> an embodiment of an aircraft <NUM> according to the present invention is illustrated. The aircraft <NUM> comprises a fuselage <NUM>, wings <NUM>, a vertical tail plane <NUM> and a horizontal tail plane <NUM>. <FIG> and <FIG> show details of the wings <NUM> of the aircraft <NUM>.

<FIG> shows an embodiment of the wing <NUM> according to the invention. The wing <NUM> comprises a main wing <NUM> and a high lift assembly <NUM>, in the present embodiment formed as a leading edge high lift assembly, movable relative to the main wing <NUM> to increase lift of the wing <NUM>. The high lift assembly <NUM> comprises a high lift body <NUM> and a connection assembly <NUM>. The high lift body <NUM> in the present embodiment is a leading edge high lift body, namely a slat. The connection assembly <NUM> is configured for connecting the high lift body <NUM> to the leading edge of the main wing <NUM> in such a way that the high lift body <NUM> is movable relative to the main wing <NUM> between a retracted position and at least one extended position.

The connection assembly <NUM> comprises a first connection element <NUM> and a second connection element <NUM>. The first connection element <NUM> is movably mounted to the main wing <NUM> and is fixedly mounted to the high lift body <NUM>. The second connection element <NUM> is movably mounted to the main wing <NUM> and is fixedly mounted to the high lift body <NUM> in a position spaced apart from the first connection element <NUM> in a wing span direction <NUM>.

Further, the connection assembly <NUM> comprises a drive system <NUM> that is fixedly mounted to the main wing <NUM> and that is connected to the high lift body <NUM> for driving the high lift body <NUM> between the retracted position and the extended position. The drive system <NUM> comprises a first drive unit <NUM> and a second drive unit <NUM> spaced apart from one another in the wing span direction <NUM>. The first drive unit <NUM> is formed as a geared rotary actuator (GRA) and has a first input section <NUM> coupled to a drive shaft <NUM>, a first gear unit <NUM>, and a first output section <NUM> drivingly coupled to the high lift body <NUM>. The second drive unit <NUM> is formed as a geared rotary actuator (GRA) and has a second input section <NUM> coupled to the drive shaft <NUM>, a second gear unit <NUM>, and a second output section <NUM> drivingly coupled to the high lift body <NUM>. The first and second gear units <NUM>, <NUM> transform high rotational speed with low torque from the first and second input sections <NUM>, <NUM>, i.e. from the drive shaft <NUM>, into low rotational speed with high torque at the first and second output sections <NUM>, <NUM>.

The first output section <NUM> comprises a rotatable first drive arm <NUM> and the second output section <NUM> comprises a rotatable second drive arm <NUM>. The first drive arm is drivingly coupled to the high lift body <NUM> via a first link element <NUM> in the form of a drive strut rotatably coupled to the first drive arm <NUM> and rotatably mounted to the high lift body <NUM>. The second drive arm <NUM> is drivingly coupled to the high lift body <NUM> via a second link element <NUM> in the form of a drive strut rotatably coupled to the second drive arm <NUM> and rotatably mounted to the high lift body <NUM>. The first link element <NUM> comprises a first linear deformation element <NUM> and the second link element <NUM> comprises a second linear deformation element <NUM>. The first linear deformation element <NUM> and the second linear deformation element <NUM> have a non-linear force-displacement characteristic <NUM>.

The first connection element <NUM> is formed as a first track <NUM> that is movably guided at the main wing <NUM> and that is fixedly mounted to the high lift body <NUM>. Additionally, the second connection element <NUM> is formed as a second track <NUM> that is movably guided at the main wing <NUM> and that is fixedly mounted to the high lift body <NUM>. The first track <NUM> and the second track <NUM> are in the form of a slat track, i.e. in the form of an elongate support beam that is movable along the direction of its elongate extension.

As shown in <FIG>, the first linear deformation element <NUM> and the second linear deformation element <NUM> are formed as a spring element <NUM> having a non-linear degressive stiffness. In the present embodiment, the spring element <NUM> is formed as a gas pressure spring. The spring element <NUM> is adapted such that the non-linear force-displacement characteristic <NUM> of the first linear deformation element <NUM> and of the second linear deformation element <NUM> is due to a combination of elastic deformation and plastic deformation. Specifically, when loading the spring element below a threshold force Fthreshold, only elastic deformation is present. When loading the spring with forces above the threshold force Fthreshold, plastic deformation of the spring is predominant, specifically by corresponding adaption the gas pressure.

As illustrated in <FIG>, the force-displacement characteristic <NUM> of the first linear deformation element <NUM> and of the second linear deformation element <NUM> has a higher slope at lower forces below the threshold force Fthreshold and has a lower slope at higher forces above the threshold force Fthreshold. The force-displacement characteristic <NUM> of the first linear deformation element <NUM> and of the second linear deformation element <NUM> is linear, i.e. has a constant first slope <NUM>, for forces below a threshold force Fthreshold. For forces above the threshold force Fthreshold the force-displacement characteristic <NUM> of the first linear deformation element <NUM> and of the second linear deformation element <NUM> is non-linear, i.e. has a second slope <NUM> different from the first slope <NUM>. In the present embodiment, the threshold force Fthreshold is about <NUM>% of the maximum force Fmax_intact_cases occurring during normal operation when both the first drive unit <NUM> and the second drive unit <NUM> are intact, which as illustrated in <FIG> in the present embodiment is between <NUM>% and <NUM>%, of the maximum force Fnon-linear associated with a maximum linear displacement Δxmax of the first or second link element <NUM>, <NUM> at a corresponding maximum skew displacement of the high lift body <NUM>. In the present embodiment shown in <FIG>, the first slope <NUM> is about <NUM> times higher than the second slope <NUM>. As shown in <FIG>, the first linear deformation element <NUM> and the second linear deformation element <NUM> have a non-linear force-displacement characteristic <NUM> with respect to forces applied to extend the high lift body <NUM>, i.e. to move the high lift body <NUM> from the retracted position to the extended position. At the same time, the first linear deformation element <NUM> and the second linear deformation element <NUM> have a linear force-displacement characteristic <NUM> with respect to forces applied to retract the high lift body <NUM>, i.e. to move the high lift body <NUM> from the extended position to the retracted position.

Claim 1:
A high lift assembly (<NUM>) for a wing (<NUM>) of an aircraft (<NUM>), comprising
a high lift body (<NUM>), and
a connection assembly (<NUM>) for movably connecting the high lift body (<NUM>) to a main wing (<NUM>), such that the high lift body (<NUM>) can be moved between a retracted position and at least one extended position,
wherein the connection assembly (<NUM>) comprises a drive system (<NUM>) that is configured to be mounted to the main wing (<NUM>) and that is connected to the high lift body (<NUM>) for driving the high lift body (<NUM>) between the retracted position and the extended position,
wherein the drive system (<NUM>) comprises a first drive unit (<NUM>) and a second drive unit (<NUM>) spaced apart from one another in a wing span direction (<NUM>),
wherein the first drive unit (<NUM>) has a first input section (<NUM>) coupled to a drive shaft (<NUM>), a first gear unit (<NUM>) and a first output section (<NUM>) drivingly coupled to the high lift body (<NUM>),
wherein the second drive unit (<NUM>) has a second input section (<NUM>) coupled to the drive shaft (<NUM>), a second gear unit (<NUM>), and a second output section (<NUM>) drivingly coupled to the high lift body (<NUM>),
wherein the first output section (<NUM>) comprises a first drive arm (<NUM>) and the second output section (<NUM>) comprises a second drive arm (<NUM>),
wherein the first drive arm (<NUM>) is drivingly coupled to the high lift body (<NUM>) via at least one first link element (<NUM>) rotatably coupled to the first drive arm (<NUM>) and mounted to the high lift body (<NUM>),
wherein the second drive arm (<NUM>) is drivingly coupled to the high lift body (<NUM>) via at least one second link element (<NUM>) rotatably coupled to the second drive arm (<NUM>) and mounted to the high lift body (<NUM>),
wherein the first link element (<NUM>) comprises a first linear deformation element (<NUM>), and/or
wherein the second link element (<NUM>) comprises a second linear deformation element (<NUM>), and
wherein the first linear deformation element (<NUM>) and/or the second linear deformation element (<NUM>) have a non-linear force-displacement characteristic,
characterized in that
the first linear deformation element (<NUM>) and/or the second linear deformation element (<NUM>) is formed as or comprises a spring element (<NUM>) having a non-linear degressive stiffness.