Installation of the helicopter's servo mechanism

Abstract

This disclosure provides a helicopter rotor head assembly (100) for controlling the swash plates (102a, 102b) of a coaxial counter-rotating helicopter rotor head. The helicopter (1000) includes a load-bearing gearbox (101) configured to drive the rotor head and support the weight of the helicopter (1000) during flight. The assembly includes at least one servo unit (104a-d) having an output shaft, a mounting structure having mounting elements configured to be fixed to the gearbox (101) and to releasably mount the servo unit, and actuators fixed to the mounting structure (106a, 106b) and connected to control rods (108a-d) that actuate the swash plates (102a, 102b). The mounting elements and actuators are configured such that the output shaft engages with the actuator by the releasably mounting of at least one servo unit (104a-d) to the mounting elements.

Description

Technical Field

[0001] The present invention relates to a component for controlling a swashplate of a helicopter, and more specifically, to the attachment of the component to the main body of the helicopter.

Background Art

[0002] Unmanned aerial vehicles (UAVs) are increasingly being used in a variety of different situations. For example, a UAV can be used for reconnaissance purposes or for the delivery of goods or payloads to a desired location. It is often desirable for the aircraft to have excellent maneuverability and thus be as small and lightweight as possible. Some UAVs can take the form of unmanned helicopters.

[0003] When the rotor blades of a helicopter rotate, the rotor blades exert torque on the helicopter, and this torque needs to be canceled out. This is generally achieved using a tail rotor that exerts an opposing torque on the main rotor in a helicopter. However, some helicopters instead cope with this by using coaxial rotors. In these aircraft, a pair of rotors are mounted on concentric shafts such that one is above the other. The two shafts have the same axis of rotation but are configured to rotate in opposite directions so that the torques balance.

[0004] The rotor blades of a helicopter are generally connected to a swashplate, and the movement and position of the swashplate can be adjusted to control the movement of the helicopter by changing the pitch of the blades.

[0005] Subsequently, the movement of the swashplate can be controlled by the operation of a control rod to which the swashplate is connected, and the control rod can be operated by one or more electric servo motors. However, due to the large weight and other forces acting on the helicopter during flight, these servo mechanisms can be subject to various loads and bending moments that can reduce the life and reliability of the servo mechanism.

[0006] The servo unit must be securely held by the helicopter to allow the control rods to operate while the helicopter is subjected to large forces during flight. Additionally, the servo unit may need to be removed or replaced over the lifespan of the helicopter. [Overview of the Initiative] [Means for solving the problem]

[0007] Embodiments of the present invention aim to address the aforementioned problems and other problems. Aspects of the present disclosure are described in the independent claims, and optional features are described in the dependent claims. Aspects of the present disclosure may be provided in relation to one another, and features of one aspect may be applied to other aspects.

[0008] In one embodiment, a helicopter rotorhead assembly for controlling the swash plate of a rotorhead of a coaxially counter-rotating helicopter is provided, wherein the helicopter comprises a load-bearing gearbox configured to drive the rotorhead to support the weight of the helicopter during flight, the assembly comprising at least one servo unit having an output shaft, a mounting structure comprising a mounting element configured to be fixed to the gearbox and to releasably mount the servo unit, and an actuator connected to a control rod for actinguating the swash plate and fixed to the mounting structure, wherein the mounting element and the actuator are configured such that the output shaft engages with the actuator by the releasably mounted at least one servo unit to the mounting element.

[0009] At least one servo unit may comprise multiple servo units, and the mounting structure may comprise multiple mounting elements, each configured to be releasably attached to one of the corresponding servo units.

[0010] The rotor head of a coaxial counter-rotating helicopter may include a first swash plate connected to a first drive shaft, and a second swash plate connected to a second drive shaft coaxial with the first drive shaft. At least one of the servo units may be configured to adjust the axial position of the first swash plate relative to the second swash plate.

[0011] At least one servo unit may comprise four servo units. Three of the servo units may be configured to control the position and / or orientation of the swash plate. A fourth servo unit may be configured to adjust the axial position of the first swash plate relative to the second swash plate.

[0012] The actuator may include a spline coupling that engages with the output shaft of the servo unit.

[0013] The actuator may have a surface with notches and / or grooves, for example, an outer surface. The notches and / or grooves may be configured to engage with a mounting structure, for example, a corresponding element on the inner surface of an opening within a mounting structure (which may be a mounting plate). The actuator may be configured to engage with the output shaft of a servo unit so that the actuator rotates together with the output shaft.

[0014] The mounting structure may be configured to support the weight of the actuator and / or servo unit.

[0015] The mounting structure may include a first plate for mounting a first pair of servo units. The mounting structure may also include a second plate for mounting a second pair of servo units. The first and second plates may be connected to both sides of the gearbox.

[0016] The helicopter rotor head assembly may further include a control arm connected to an actuator. The control arm may be positioned to connect to a control rod and may be configured to convert the rotational movement of the actuator into the linear movement of the control rod. The helicopter rotor head assembly may also include a control rod that actsuates the rotating swash plate.

[0017] The gearbox may have an opening. A control rod (for example, one of four control rods) may be positioned to pass through the opening between the actuator and the rotating swash plate.

[0018] The helicopter rotor head assembly may further include control arms; for example, the rotor head assembly may have multiple control arms, such as four.

[0019] At least one servo unit may correspond to a servo unit, for example, a single servo unit. The servo unit may be a first servo unit, and the rotor head assembly may comprise multiple servo units, including the first servo unit. For example, the rotor head assembly may comprise four servo units. Three of the servo units, for example, three of the four servo units, may be configured to control the position and / or orientation of the swashplate.

[0020] At least one servo unit may comprise a first pair of servo units, for example, a first pair of four servo units, which may be identical or substantially identical. The pair of servo units may be configured to be releasably mounted to a first common element of the mounting structure, for example, a first frame element or a mounting plate. At least one servo unit may comprise a second pair of servo units, for example, a second pair of four servo units, which may be substantially identical to each other and / or to the first pair of servo units, and may be mountable to a second common element of the mounting structure, for example, a second frame element or a mounting plate. The first and second common elements may be located on either side of the gearbox. Each pair of servo units may be positioned to extend parallel to each other from the mounting structure.

[0021] A frame element, for example, a mounting plate, may further include connection points for attaching the mounting structure to the gearbox. The connection points may include openings for screws that extend through the gearbox and are attached to the gearbox. Each mounting structure, for example, a frame element, may include one or more (e.g., a pair) projections that include connection points. The mounting structure may include one or more openings through which the corresponding actuator and / or output shaft extends.

[0022] Corresponding actuators and control rods may be provided for each servo unit. Each actuator may be an elongated element that extends between the output shaft of the servo unit and a control arm, or may comprise such an element. Alternatively, the actuator may comprise a control arm. The actuator may be configured to transmit rotational motion from the output shaft of the servo unit to the control arm and / or control rod. For example, the control arm may convert the rotational motion into linear motion of the control rod.

[0023] The rotor head assembly may further include one or more bearings, such as angular ball bearings, configured to support radial and / or axial loads in, for example, an actuator. The one or more bearings may each surround a respective actuator and / or may be provided inside one of the openings in the mounting structure.

[0024] The actuator may include, for example, a plurality of notches / ridges / grooves / splines on a part of the surface of the actuator, such as the control arm 13 and / or that engage with the bearing. For example, the plurality of notches / ridges / grooves / splines may be configured to engage with corresponding shaped elements in the control arm 13 and / or the bearing.

[0025] The rotor head assembly of a helicopter may include a load support gearbox.

[0026] One or more servo units may be attached to the mounting structure.

[0027] The mounting element and the actuator may be arranged such that when at least one servo unit is detachably attached to the mounting element, the output shaft of the servo unit engages with the actuator.

[0028] The mounting element may include one or more screws. Each servo unit may be detachable from the mounting structure when the screw is removed. The mounting structure may include one or more mounting plates. In some examples, the mounting structure includes a pair of mounting plates. In some examples, the first pair of servo units may be detachably attached to the first mounting plate, and the second pair of servo units may be detachably attached to the second mounting plate. <opposite text=

[0029] The rotor head assembly may include a plurality of servo units and a corresponding plurality of actuators, and each servo unit is associated with a corresponding actuator. Each servo unit and the associated actuator may further be associated with a corresponding control rod. It will be understood that the control rod need not form part of the rotor head assembly. In some examples, there may be four sets of associated servo units, actuators (and control rods).

[0030] Each servo unit and / or actuator may be configured to operate a corresponding control rod of the same servo unit and / or actuator so as to control a rotor blade of the helicopter, for example, to provide collective pitch control and / or cyclic pitch control.

[0031] In another aspect, a method for replacing a servo unit of a rotor head assembly of a helicopter is provided. The method includes removing a first servo unit from a mounting element and attaching a second servo unit to the mounting element.

Brief Description of the Drawings

[0032] Here, an example of the present disclosure will be described with reference to the drawings. [Figure 1] FIG. 1 provides a schematic view showing an example of a coaxial helicopter. [Figure 2a] FIG. 2a shows a schematic side view of an example of a rotor head assembly of a helicopter. [Figure 2b] FIG. 2b shows a schematic front view of an example of an exemplary rotor head assembly of a helicopter. [Figure 3] FIG. 3 shows a part of an example of a mounting structure for a servo unit of a rotor head assembly of a helicopter.

[0033] In the drawings, the same reference numerals are used to indicate the same elements. [Modes for carrying out the invention]

[0034] This disclosure relates to a mounting mechanism that enables a servo unit for operating the swash plate of a coaxial helicopter to be mounted on the helicopter without substantially supporting the helicopter's load. This allows the servo unit to be easily removed and replaced. The servo unit is releasably mounted to a mounting frame connected to the helicopter's gearbox, which supports the helicopter's weight during flight. Furthermore, the servo unit engages with a control rod mechanism through its mounting to the mounting structure, thereby enabling control of the helicopter's swash plate and rotor blades.

[0035] Figure 1 shows a schematic side view of an example of a coaxial helicopter 1000. The coaxial helicopter 1000 comprises a first rotor 1002 having multiple (e.g., three) rotor blades. The helicopter 1000 further comprises a second rotor 1004 having a corresponding number of rotor blades.

[0036] The helicopter 1000 further comprises a gearbox or transmission 101. The gearbox 101 is connected to an engine or other power source (neither shown) and is configured to drive rotors 1002 and 1004, respectively. As shown in the figure, during operation, the first rotor 1002 and the second rotor 1004 are configured to rotate in opposite directions to provide lift to the helicopter 1000 while balancing torque.

[0037] The gearbox 101 is mechanically connected to drive the first rotor 1002 via the first drive shaft 1006 and to drive the second rotor 1004 via the second drive shaft 1008. The first drive shaft 1006 and the second drive shaft 1008 are concentric, for example, concentric cylindrical, and the second drive shaft 1008 is positioned inside the first drive shaft 1006. The first drive shaft 1006, the second drive shaft 1008, the first rotor 1002, and the second rotor 1004 are coaxial, that is, the first drive shaft 1006, the second drive shaft 1008, the first rotor 1002, and the second rotor 1004 share a rotation axis.

[0038] Figure 2a shows a schematic side view of an example of a helicopter rotor head assembly 100 for a coaxial helicopter having a pair of counter-rotating rotors, such as helicopter 1000 in Figure 1. Figure 2b shows a front view of the same assembly 100. For clarity, the coaxial drive shaft and rotor blades are not shown in these figures. Assembly 100 includes a gearbox 101, such as the gearbox 101 mentioned above. The gearbox is configured to support the weight of the helicopter during flight; that is, during flight, the weight of the helicopter acts through the gearbox 101.

[0039] Assembly 100 further comprises a first swash plate 102a and a second swash plate 102b. Each of the first and second swash plates 102a and 102b is configured to control the movement of the helicopter, for example, by adjusting the pitch of the rotor blades of the rotors, thereby controlling the movement of the first rotor 1002 and the second rotor 1004, respectively. The movement of the swash plates 102a and 102b is controlled by a plurality of servo units 104a to d. Each of the servo units 104a to d is mechanically connected to one or both of the swash plates 102a and 102b via corresponding control rods 108a to d. The servo units 104a to d are operable to actuate the corresponding control rods 108a to d of the servo units 104a to d in order to adjust the movement, position, and / or orientation of the swash plates 102a and 102b.

[0040] The servo units 104a to d are configured to actuate control rods 108a to d in response to control signals that may be received from a controller (not shown) to which the servo units 104a to d are connected. Each servo unit 104a to d comprises a servo motor and a position sensor configured to provide position feedback to the motor.

[0041] Assembly 100 comprises four identical servo units. The four servo units 104a-d are mounted to the gearbox 101 via a mounting structure 105, and in particular, mounted on the gearbox 101. The mounting structure 105 comprises a first mounting plate 106a and a second mounting plate 106b. The first servo unit 104a and the second servo unit 104b are mounted to the first mounting plate 106a, and the second servo unit 104b and the third servo unit 104c are mounted to the second mounting plate 106b. The first mounting plate 106a and the second mounting plate 106b are mounted on both sides, for example, on both sides of the gearbox 101. The first mounting plate 106a is connected to the second mounting plate 106b via a rigid frame 107. Each of the servo units 104a-d is releasably mounted to the corresponding mounting plates 106a-b of the servo units 104a-d, as will be described in more detail below.

[0042] As shown in Figures 2a to 2b, the servo units 104a to 104d are mounted on the gearbox 101 such that the servo units 104a to 104d are positioned on both sides of the gearbox 101 relative to the swash plates 102a to 102b. In particular, the servo units 104a to 104d are provided in such a manner that they constitute the underside of the gearbox 101 during flight. Therefore, each of the control rods 108a to 108d needs to extend around or through the gearbox 101. As shown in Figures 2a to 2b, in the assembly 100, three of the control rods 108a to 108c extend around the outside of the gearbox 101. The fourth control rod 108d is configured to extend through an opening in the gearbox, which extends axially from the lower surface of the gearbox to the upper surface of the gearbox.

[0043] The first three servo units 104a to c and the control rod 108a may be configured to adjust the movement, position, and / or orientation of the rotating swash plates 102a and 102b, while the fourth servo unit 104d and the control rod 104d may be configured to provide differential control, i.e., to adjust the position of the first rotating swash plate 102a relative to the second rotating swash plate 102b.

[0044] Figure 3 is an exploded view of a portion of assembly 100, showing in more detail an example of the connection between the servo unit and the mounting structure. Assembly 100 in Figure 3 is shown with its orientation reversed perpendicularly to that of Figures 2a and 2b.

[0045] As shown in the figure, each of the pair of servo units 104 is provided with an output shaft 302 configured to rotate when the servo unit 104 is in operation. The pair of servo units 104 are also configured to be mechanically connected to each other via connecting means in the form of screws 15 at the outer ends of the servo units 104, i.e., the ends opposite to the ends that engage with the mounting plate 106.

[0046] The mounting plate 106 has a pair of openings through which the output shafts 302 of each of the two servo units 104 extend. The mounting plate 106 has connection points (e.g., holes) that connect to alignment connection points in each of the servo units 104 via mounting elements, in particular a pair of screws 14. The mounting plate 106 further has a pair of projections that have connection points in the form of openings for connection to a gearbox via a pair of screws 17 on each projection.

[0047] Each servo unit 104 is attached to the mounting plate 106 via screws 14, and can be released from the mounting plate 106 by removing the screws 14. Thus, the servo units 104 can be removed or replaced in the assembly. Therefore, the screws 14 can be considered mounting elements, individually or collectively, configured to releasely attach the corresponding servo unit 104 of the mounting element to the mounting structure (e.g., the mounting plate 106).

[0048] When the servo unit 104 is mounted on the mounting plate 106, each of the output shafts 302 is configured to engage with an actuator in the form of an actuation element 9. The actuation element 9 is fixed to the mounting plate 106. For example, a portion of the actuation element 9 has a surface with notches and grooves configured to engage with a corresponding element on the inner surface of an opening in the mounting plate 106. The actuation element 9 is an elongated element configured to engage with the output shaft 302 so that the actuation element 9 rotates with the output shaft 302. The actuation element 9 extends from the mounting plate 106 and is configured to transmit rotational movement from the output shaft 302 to a control rod (for example, the control rod shown in Figures 2a-b). In particular, each of the actuation elements 9 is configured to engage with a control arm 13. Each of the control arms 13 is positioned to connect to one of the control rods that actuate the swashplate of the helicopter. The control arm 13 is configured to convert the rotational movement of the actuation element 9 into linear movement of the control rod to which the control arm 13 is attached. In particular, the control arm 13 comprises a circular portion configured to engage with the end of the actuating element 9 and rotate around the axis of the actuating element 9, and a substantially rectangular portion extending from one side of the circular portion. The rectangular portion is connected to the control rod such that the rotational movement of the control arm 13 provides the linear movement of the control rod.

[0049] The control arm 13 is supported within a support element 8. The support element 8 is attached to a mounting plate 106. In particular, the support element 8 is attached via screws 4 to the side of the mounting plate 106 opposite to the servo unit 104. The support element 8 substantially surrounds the control arm 13 but has an opening through which a rectangular portion extends, allowing the control arm 13 to rotate around the axis of the actuarial element 9. The support element 8 includes a support rim 6 having a diameter larger than the diameter of the body of the support element 8. The support rim 6 is connected to the mounting plate 106 via a plurality of screws 4, for example, six screws 4.

[0050] The actuating element 9 includes a portion that extends into the support element 8 and engages with the control arm. A pair of angular contact ball bearings 2,7 surround this portion of the support element 8 and are connected together via a circlip 25. The bearing 2 closest to the control arm 13 may have a larger diameter than the bearing 7 closest to the mounting plate 106. The bearings 7 and / or 2 are mounted on the actuating element 9.

[0051] The actuating element 9 may have a plurality of notches / ridges / grooves / splines on a portion of its surface that engage with the control arm 13 and / or bearings 2,7.

[0052] Further angular contact ball bearings 7' may be mounted on the actuating element 9 on the control arm 13 opposite to bearings 7,2.

[0053] Further connection mechanisms are provided for each control arm 13, comprising a screw 20, a nut 21, and a pin 23, wherein the screw 20 extends through a hole in a rectangular portion of the control arm 13 so that the control arm 13 is secured between the head of the screw 20 and the nut 21, and is used to rigidly connect the control arm 13 to the corresponding control rod 108. The hole / opening in the control arm is provided at the end of the control arm 13 furthest from the rotational connection to the actuation element 9.

[0054] From the above description, it will be understood that the example shown in the figures is merely illustrative and may include features that are generalized, omitted, or replaced as described herein and in the claims. Generally, referring to the drawings, it will be understood that schematic functional block diagrams are used to illustrate the functions of the systems and devices described herein.

[0055] As will be understood by those skilled in the art in the context of this disclosure, each example described herein may be implemented in a variety of different ways. Any feature of any aspect of this disclosure may be combined with any of the other aspects of this disclosure. For example, a method aspect may be combined with an apparatus aspect, and a feature described with reference to the operation of a particular element of an apparatus may be provided in a way that does not use that particular type of apparatus. Furthermore, unless it is expressly stated that some other feature is essential to the operation of that feature, each feature relating to each example is intended to be separable from the feature that each separable feature describes in combination with. Each separable feature may, of course, be combined with any other feature of the example that each separable feature describes, or with any other feature or combination of features relating to any of the other examples described herein. Furthermore, equivalents and modifications not described herein may be adopted without departing from the invention.

[0056] Other examples and variations of this disclosure will be apparent to those skilled in the art in the context of this disclosure.

Claims

1. A helicopter rotor head assembly for controlling the swashplate of a coaxial counter-rotating helicopter rotor head, The aforementioned helicopter is, A load-bearing gearbox configured to drive the rotor head and support the weight of the helicopter during flight, Equipped with, The aforementioned assembly is A servo unit having an output shaft, A mounting structure comprising a mounting element configured to be fixed to the gearbox and configured to releasably mount the servo unit, An actuator connected to a control rod that operates the rotating swashplate and fixed to the mounting structure, Equipped with, The mounting element and the actuator are configured such that the output shaft engages with the actuator by a releasable mounting of the at least one servo unit to the mounting element. A helicopter rotor head assembly characterized by the following features.

2. The at least one servo unit is Multiple servo units, Equipped with, The aforementioned mounting structure is A plurality of mounting elements, each configured to be releasably attached to one of the corresponding servo units, Equipped with, The rotor head assembly for a helicopter according to claim 1.

3. The rotor head of the aforementioned coaxial counter-rotating helicopter is A first rotating swash plate connected to the first drive shaft, A second rotating swash plate connected to a second drive shaft which is coaxial with the first drive shaft, Equipped with, At least one of the servo units is configured to adjust the axial position of the first swash plate relative to the second swash plate. A helicopter rotor head assembly according to claim 1 or 2.

4. The at least one servo unit is Four servo units, Equipped with, Three of the servo units are configured to control the position and / or orientation of the rotating swash plate. A helicopter rotor head assembly according to any one of claims 1 to 3.

5. The remaining servo unit is configured to adjust the axial position of the first swash plate relative to the second swash plate. A helicopter rotor head assembly according to claim 4, dependent on claim 3.

6. The actuator is A spline coupling that engages with the output shaft of the servo unit, Equipped with, A helicopter rotor head assembly according to any one of claims 1 to 5.

7. The mounting structure is configured to support the weight of the actuator and / or the servo unit. A helicopter rotor head assembly according to any one of claims 1 to 6.

8. The aforementioned mounting structure is A first plate for attaching the first pair of servo units, A second plate for mounting the second pair of servo units, Equipped with, The first plate and the second plate are connected to both sides of the gearbox. A helicopter rotor head assembly according to any one of claims 1 to 7.

9. A control arm, which is connected to the actuator and positioned to be connected to the control rod, Equipped with, The control arm is configured to convert the rotational movement of the actuator into the linear movement of the control rod. A helicopter rotor head assembly according to any one of claims 1 to 8.

10. The aforementioned gearbox is opening, Equipped with, The control rod is positioned to pass through the opening between the actuator and the rotating swash plate. A helicopter rotor head assembly according to any one of claims 1 to 9.

11. Control arm, Having, A helicopter rotor head assembly according to any one of claims 1 to 10.

12. A method for replacing a servo unit of a helicopter rotor head assembly according to any one of claims 1 to 11, The aforementioned method, Removing the first servo unit from the mounting element, The second servo unit is attached to the mounting element, including, A method characterized by the following:

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