Patent Description:
<CIT> discloses a VTOL aircraft including a plurality of VTOL rotors and a plurality of cruise rotors. The cruise rotors each include a motor, a propeller, and a duct. The duct includes a cylinder, a hub, and a plurality of stators. The cylinder is disposed around the propeller. The hub is disposed inside the cylinder. Each stator extends radially from the hub to the cylinder.

In the VTOL aircraft disclosed in <CIT>, each stator of the duct is arranged forward of the propeller. In this structure, the stator blocks the flow of air sucked into the propeller. Then, the flow of air sucked into the propeller is disturbed, and noise is generated. <CIT> and <CIT> each disclose a thrust generating device including at least one propeller configured to generate thrust for causing an aircraft to move forward, the thrust generating device comprising: a propeller unit including the propeller, and a duct configured to cover a periphery of the propeller, wherein the duct includes a cylinder disposed around the propeller, a hub disposed inside the cylinder, and a plurality of stators extending radially from the hub to the cylinder, and the hub and each of the stators are disposed rearward of the propeller. A similar thrust generating device is shown in <CIT>. <CIT> discloses motor supported rearward of a rear wing of an aircraft. <CIT> shows a harness to pass through rear wing, stay, cylinder, stator, and hub. In <CIT> wings are arranged in a straight line with the respective two stators and hub of each propeller unit.

An object of the present invention is to solve the above-mentioned problem.

According to the present invention, there is provided a thrust generating device according to claim <NUM>.

According to the present invention, the thrust generating device includes at least one propeller configured to generate thrust for causing the aircraft to move forward, the thrust generating device including the propeller unit including the propeller and the duct configured to cover the periphery of the propeller, wherein the duct includes the cylinder disposed around the propeller, the hub disposed inside the cylinder, and the plurality of stators extending radially from the hub to the cylinder, and the hub and each of the stators are disposed rearward of the propeller.

According to the above configuration, it is possible to suppress noise caused by the stators. In addition, according to the above configuration, it is possible to prevent the amount of air sucked into the propeller from being limited due to the stators.

The propeller unit is supported by a rear wing of the aircraft and disposed rearward of the rear wing.

The thrust generating device further includes a motor that includes a rotation shaft connected to the propeller and that is configured to rotate the propeller, the motor is supported by the rear wing, and the propeller unit is disposed rearward of the motor.

The hub is connected to the rotation shaft of the motor via a bearing.

According to the above configuration, since the propeller, which is the vibration source, is located near the support point of the support member, it is possible to suppress vibration of the entire thrust generating device.

The propeller unit may include a shaft protruding rearward from the propeller, and the hub may be connected to the shaft via the bearing.

The thrust generating device may further include a first propeller unit and a second propeller unit as the propeller unit, and a connector disposed between the first propeller unit and the second propeller unit and configured to connect the first propeller unit and the second propeller unit, the first propeller unit may include a first duct as the duct, the second propeller unit may include a second duct as the duct, the first propeller unit and the second propeller unit may be lined up in the width direction of the aircraft, and the connector may connect the first duct and the second duct to each other.

In the above aspect, the first duct may include the first cylinder as the cylinder, the first hub as the hub, and two first stators as the stators, the second duct may include the second cylinder as the cylinder, the second hub as the hub, and two second stators as the stators, the connector may connect the first cylinder and the second cylinder to each other, and the connector, the first hub, the two first stators, the second hub, and the two second stators may be arranged in a straight line.

According to the above configuration, the rigidity of each cylinder is increased. Further, according to the above configuration, the moment acting on the support portion of the cruise rotor is reduced.

According to the present invention, the noise of the cruise rotors can be suppressed.

<FIG> is an external view of a VTOL aircraft <NUM>. The VTOL aircraft <NUM> is, for example, an electric vertical takeoff and landing aircraft, or a so-called eVTOL aircraft. The VTOL aircraft <NUM> includes a fuselage <NUM>, a front wing <NUM>, a rear wing <NUM>, two booms <NUM>, eight VTOL rotors <NUM>, and two cruise rotors <NUM>.

In this specification, a direction in which the VTOL aircraft <NUM> flies when cruising is referred to as "forward", and a direction opposite to "forward" is referred to as "rearward". The forward flight of the VTOL aircraft <NUM> is referred to as "forward movement".

The front wing <NUM> is connected to a front portion of the fuselage <NUM>. The rear wing <NUM> is connected to a rear portion of the fuselage <NUM>. The front wing <NUM> and the rear wing <NUM> generate lift as the VTOL aircraft <NUM> moves forward.

A boom 18R of the two booms <NUM> is disposed on the right side of the fuselage <NUM>. A boom <NUM> of the two booms <NUM> is disposed on the left side of the fuselage <NUM>. Each boom <NUM> extends in the front-rear direction.

Four VTOL rotors <NUM> are arranged on the boom <NUM> sequentially toward the rear. Similarly, four VTOL rotors <NUM> are arranged on the boom 18R sequentially toward the rear. Each VTOL rotor <NUM> is used during takeoff, during vertical climb, during transition from climb to cruise, during transition from cruise to descent, during vertical descent, during landing, and during hovering. Each VTOL rotor <NUM> generates thrust in the vertical direction.

Two cruise rotors <NUM> are disposed on the rear wing <NUM> so as to be arranged side by side in the left-right direction. Each cruise rotor <NUM> is used during cruise, during transition from climb to cruise, and during transition from cruise to descent. Each cruise rotor <NUM> generates thrust in the horizontal direction. The one or more cruise rotors <NUM> included in the VTOL aircraft <NUM> are referred to as a thrust generating device <NUM>.

The thrust generating device <NUM> causes air to flow from the front to the rear. As a result, the thrust generating device <NUM> generates thrust for flying the VTOL aircraft <NUM> in a substantially horizontal direction.

<FIG> is a schematic view in which the structure of the cruise rotor <NUM> of the thrust generating device <NUM> according to a first embodiment is simplified. The schematic view of <FIG> is a top view of the cruise rotor <NUM> in which a cylinder <NUM> of a duct <NUM> is vertically cut in half. The cruise rotor <NUM> includes one or more support members <NUM>, a motor <NUM>, and a propeller unit <NUM>. The propeller unit <NUM> includes a propeller <NUM>, a shaft member <NUM>, and the duct <NUM>.

The propeller unit <NUM> is supported by the rear wing <NUM> via the support member <NUM> and the motor <NUM>. The axis of the motor <NUM>, the axis of the propeller <NUM> (the axis of a blade hub <NUM>), the axis of the shaft member <NUM>, and the axis of the duct <NUM> (the axes of the cylinder <NUM> and a duct hub <NUM>) are the same.

The motor <NUM> is supported by the support member <NUM>. The motor <NUM> is connected to a rear end portion of the support member <NUM>. The support member <NUM> is, for example, a pipe-shaped shaft. The support member <NUM> extends in the front-rear direction. The support member <NUM> is housed inside the rear wing <NUM> and is supported by a member provided inside the rear wing <NUM>. That is, the motor <NUM> is supported by the rear wing <NUM> via the support member <NUM>. A rotation shaft <NUM> of the motor <NUM> extends rearward.

A harness <NUM> for supplying electric power to the motor <NUM> is connected to the motor <NUM>. The harness <NUM> extends from a power source (not shown) through the insides of the rear wing <NUM> and the support member <NUM>, and is connected to the motor <NUM>.

The propeller <NUM> includes the blade hub <NUM> and a plurality of blades <NUM>. The propeller <NUM> is disposed rearward of the rear wing <NUM> and the motor <NUM>. The blade hub <NUM> is arranged at the center of the propeller <NUM>. The blade hub <NUM> is connected to a rear end portion of the rotation shaft <NUM> of the motor <NUM>. Each blade <NUM> extends radially from the blade hub <NUM>. Each blade <NUM> is connected to an outer circumferential surface of the blade hub <NUM>.

The shaft member <NUM> is disposed rearward of the propeller <NUM>. The shaft member <NUM> includes, for example, a pipe-shaped shaft portion. The shaft member <NUM> is connected to the blade hub <NUM> and extends rearward from the blade hub <NUM>. Details of the shaft member <NUM> will be described later.

The duct <NUM> includes the cylinder <NUM>, the duct hub <NUM>, and a plurality of duct stators <NUM>. The cylinder <NUM> is open forward and rearward. The cylinder <NUM> is disposed around the propeller <NUM>. Specifically, the cylinder <NUM> is disposed so as to intersect the direction in which each blade <NUM> extends. The cylinder <NUM> covers the periphery of the propeller <NUM> and a space located rearward of the propeller <NUM>. The duct hub <NUM> is disposed inside the cylinder <NUM> and rearward of the propeller <NUM>. The duct hub <NUM> is connected to the shaft member <NUM>. Each duct stator <NUM> extends radially from the duct hub <NUM> to the cylinder <NUM>. Each duct stator <NUM> is connected to an outer circumferential surface of the duct hub <NUM> and an inner circumferential surface of the cylinder <NUM>. Each duct stator <NUM> is disposed rearward of the propeller <NUM>.

<FIG> is a schematic view in which a structure of mounting the duct hub <NUM> to the shaft member <NUM> is simplified. In <FIG>, the duct stator <NUM> is omitted. The duct hub <NUM> is connected to the shaft member <NUM> via a front bearing <NUM> and a rear bearing <NUM>. The front bearing <NUM> is disposed forward of the rear bearing <NUM>. The outer diameter of the front bearing <NUM> is larger than the outer diameter of the rear bearing <NUM>.

The shaft member <NUM> includes a mounting portion <NUM>, a large diameter portion <NUM>, and a small diameter portion <NUM>. The mounting portion <NUM> is connected to a rear end portion of the blade hub <NUM>. The large diameter portion <NUM> and the small diameter portion <NUM> are pipe-shaped shafts. The large diameter portion <NUM> extends rearward from a rear end portion of the mounting portion <NUM>. The small diameter portion <NUM> extends rearward from a rear end portion of the large diameter portion <NUM>. The outer diameter of the large diameter portion <NUM> is larger than the outer diameter of the small diameter portion <NUM>.

The small diameter portion <NUM> is press-fitted into an inner ring 66a of the front bearing <NUM> and an inner ring 68a of the rear bearing <NUM>. Further, the small diameter portion <NUM> is inserted through a front collar <NUM> and a rear collar <NUM>. Furthermore, a nut <NUM> is attached to a rear end portion of the small diameter portion <NUM>. The front bearing <NUM> is positioned by the inner ring 66a of the front bearing <NUM> abutting against the rear end portion of the large diameter portion <NUM>. The front collar <NUM> is interposed between the inner ring 66a of the front bearing <NUM> and the inner ring 68a of the rear bearing <NUM>. The front collar <NUM> abuts against a rear end portion of the inner ring 66a of the front bearing <NUM>, and a front end portion of the inner ring 68a of the rear bearing <NUM>. The rear bearing <NUM> is positioned by the inner ring 68a of the rear bearing <NUM> abutting against a rear end portion of the front collar <NUM>. The rear collar <NUM> is interposed between the rear bearing <NUM> and the nut <NUM>. The rear collar <NUM> abuts against a rear end portion of the inner ring 68a of the rear bearing <NUM> and a front end portion of the nut <NUM>. The nut <NUM> is positioned by abutting against a rear end portion of the rear collar <NUM>.

The duct hub <NUM> is provided with a through-hole <NUM> penetrating in the front-rear direction. The through-hole <NUM> includes a large diameter hole <NUM> and a small diameter hole <NUM>. The inner diameter of the large diameter hole <NUM> is larger than the inner diameter of the small diameter hole <NUM>. A step <NUM> is formed at a boundary between the large diameter hole <NUM> and the small diameter hole <NUM>.

The front bearing <NUM> and the rear bearing <NUM> are attached to the shaft member <NUM> in advance. The shaft member <NUM> is inserted into the through hole <NUM> from the front side. Then, the rear bearing <NUM> is press-fitted into the small diameter hole <NUM>. Further, the front bearing <NUM> is press-fitted into the large diameter hole <NUM>. The duct hub <NUM> is positioned relative to the shaft member <NUM> by a rear end portion of the front bearing <NUM> and the step <NUM> abutting against each other. Further, a snap ring <NUM> which abuts against a front end portion of the front bearing <NUM> is fitted to the duct hub <NUM>.

With the structure described above, the duct <NUM> is connected to the rear wing <NUM> via the two bearings (the front bearing <NUM> and the rear bearing <NUM>), the shaft member <NUM>, the propeller <NUM>, the motor <NUM>, and the support member <NUM>. That is, the duct <NUM> is supported by the rear wing <NUM>.

<FIG> is a rear view of the thrust generating device <NUM>. A fairing <NUM> is attached to a rear end portion of the shaft member <NUM> of each cruise rotor <NUM> (the rear end portion of the small diameter portion <NUM>). A cylinder <NUM> of a cruise rotor <NUM> on the left side and a cylinder 50R of a cruise rotor 22R on the right side are connected to each other by a connector <NUM>. The connector <NUM> includes a left connector <NUM> and a right connector 90R. The left connector <NUM> is connected to a right end portion of an outer circumferential surface of the cylinder <NUM> and protrudes rightward. The right connector 90R is connected to a left end portion of an outer circumferential surface of the cylinder 50R and protrudes leftward. The left connector <NUM> and the right connector 90R are connected to each other. Note that the cylinder <NUM> and the cylinder 50R may be directly connected to each other without interposing the connector <NUM> therebetween.

As described above, the duct <NUM> is connected to the shaft member <NUM> via the two bearings (the front bearing <NUM> and the rear bearing <NUM>). If the duct <NUM> is not connected to any member other than the shaft member <NUM>, the duct <NUM> is rotatable with respect to the shaft member <NUM>. However, in the present embodiment, as shown in <FIG>, the two left and right ducts <NUM> are connected to each other. With this structure, each duct <NUM> does not rotate.

As shown in <FIG>, the duct <NUM> preferably includes four duct stators <NUM>. The four duct stators <NUM> are arranged at equal intervals (<NUM> degree intervals) around the duct hub <NUM>. A duct stator 54a extends leftward from the duct hub <NUM> toward the cylinder <NUM>. A duct stator 54b extends rightward from the duct hub <NUM> toward the cylinder <NUM>. A duct stator 54c extends upward from the duct hub <NUM> toward the cylinder <NUM>. A duct stator 54d extends downward from the duct hub <NUM> toward the cylinder <NUM>.

As shown in <FIG>, from left to right, the duct stator 54a (a first stator) of the cruise rotor <NUM>, the duct hub <NUM> of the cruise rotor <NUM>, the duct stator 54b (the first stator) of the cruise rotor <NUM>, the connector <NUM>, the duct stator 54a (a second stator) of the cruise rotor 22R, the duct hub <NUM> of the cruise rotor 22R, and the duct stator 54b (the second stator) of the cruise rotor 22R are arranged in a straight line. With this structure, the rigidity of each cylinder <NUM> is increased. Further, with this structure, the moment acting on the support portion (the support member <NUM>) of the cruise rotor <NUM> is reduced.

Note that, as shown in <FIG>, the duct <NUM> may include three duct stators <NUM>. In this mode, from left to right, the duct hub <NUM> of the cruise rotor <NUM>, one duct stator <NUM> of the cruise rotor <NUM>, the connector <NUM>, one duct stator <NUM> of the cruise rotor 22R, and the duct hub <NUM> of the cruise rotor 22R are preferably arranged in a straight line. With this structure, the moment acting on the support portion (the support member <NUM>) of the cruise rotor <NUM> is reduced.

As described above, in the first embodiment, each duct stator <NUM> is disposed rearward of the propeller <NUM>. Therefore, each duct stator <NUM> does not block the flow of air sucked into the propeller <NUM> from the front side in accordance with the rotation of the propeller <NUM>. Therefore, according to the first embodiment, it is possible to suppress noise caused by the duct stators <NUM>. Further, according to the first embodiment, it is possible to prevent the amount of air sucked into the propeller <NUM> from being limited due to the duct stators <NUM>.

<FIG> is a schematic view in which the structure of the cruise rotor <NUM> of the thrust generating device <NUM> according to an example not presently being claimed is simplified. The schematic view of <FIG> is a top view of the cruise rotor <NUM> in which the cylinder <NUM> of the duct <NUM>, the blade hub <NUM>, and a motor <NUM> are vertically cut in half. In this example, the same components as those in the first embodiment are denoted by the same reference numerals. The cruise rotor <NUM> includes one or more support members <NUM>, the motor <NUM>, and the propeller unit <NUM>.

The propeller unit <NUM> includes the propeller <NUM> and the duct <NUM>. The propeller unit <NUM> is supported by the rear wing <NUM> via the support member <NUM>. As shown in <FIG>, the propeller <NUM> is disposed rearward of the motor <NUM>. The duct hub <NUM> and each duct stator <NUM> are disposed rearward of the propeller <NUM>. In this example, the duct <NUM> is directly connected to the support member <NUM>.

The motor <NUM> is supported by the support member <NUM>. The motor <NUM> is an outer rotor motor including a rotor 94R outside a stator <NUM>. The motor <NUM> is connected to a rear end portion of the support member <NUM>. The support member <NUM> includes, for example, a pipe-shaped shaft. The support member <NUM> extends in the front-rear direction. The support member <NUM> passes through respective central portions of the stator <NUM>, the rotor 94R, the rotation shaft <NUM>, and the propeller <NUM>, and is connected to the duct hub <NUM>. A portion of the support member <NUM> is housed inside the rear wing <NUM> and is supported by a member provided inside the rear wing <NUM>.

In this example, each duct stator <NUM> is disposed rearward of the propeller <NUM>. Therefore, each duct stator <NUM> does not block the flow of air sucked into the propeller <NUM> from the front side in accordance with the rotation of the propeller <NUM>. Therefore, according to this example, it is possible to suppress noise caused by the duct stators <NUM>. Further, according to this example, it is possible to prevent the amount of air sucked into the propeller <NUM> from being limited due to the duct stators <NUM>.

In this example the connector <NUM> shown in <FIG> may be provided between two ducts <NUM> arranged side by side in the left-right direction. Also, the duct stators <NUM> may be arranged as shown in <FIG> or <FIG>.

<FIG> is a schematic view in which the structure of the cruise rotor <NUM> of the thrust generating device <NUM> according to another example not presently being claimed is simplified. The schematic view of <FIG> is a top view of the cruise rotor <NUM> in which the cylinder <NUM> of the duct <NUM>, and the blade hub <NUM> are vertically cut in half. In this example, the same components as those in the first embodiment are denoted by the same reference numerals. The cruise rotor <NUM> includes two support members <NUM>, the motor <NUM>, and the propeller unit <NUM>.

The propeller unit <NUM> includes the propeller <NUM> and the duct <NUM>. The propeller unit <NUM> is supported by the rear wing <NUM> via the support members <NUM>. As shown in <FIG>, the propeller <NUM> is disposed forward of the motor <NUM>. The duct hub <NUM> and each duct stator <NUM> are disposed rearward of the propeller <NUM>.

The two support members <NUM> are stays. One support member <NUM> is connected to the left side of an outer circumferential surface of the cylinder <NUM>. The other support member <NUM> is connected to the right side of the outer circumferential surface of the cylinder <NUM>. Each support member <NUM> is also connected to the rear wing <NUM>. With this structure, the duct <NUM> is supported by the rear wing <NUM> via the two support members <NUM>.

The motor <NUM> is housed inside the duct hub <NUM>. The rotation shaft <NUM> of the motor <NUM> extends forward. A front end portion of the rotation shaft <NUM> is connected to the blade hub <NUM>. The motor <NUM> is supported by the rear wing <NUM> via the duct <NUM> and the two support members <NUM>.

The harness <NUM> extends from a power source (not shown) through the insides of the rear wing <NUM>, the support member <NUM>, the cylinder <NUM>, and the duct hub <NUM>, and is connected to the motor <NUM>.

In this example, a shared support member <NUM> may be provided between the two ducts <NUM> arranged side by side in the left-right direction. Also, the duct stators <NUM> may be arranged as shown in <FIG> or <FIG>.

Claim 1:
A thrust generating device (<NUM>) including at least one propeller (<NUM>) configured to generate thrust for causing an aircraft (<NUM>) to move forward, the thrust generating device comprising:
a propeller unit (<NUM>) including the propeller; a duct (<NUM>) configured to cover a periphery of the propeller; and
a motor (<NUM>, <NUM>) that includes a rotation shaft (<NUM>) connected to the propeller, and that is configured to rotate the propeller,
wherein the duct includes a cylinder (<NUM>) disposed around the propeller, a hub (<NUM>) disposed inside the cylinder, and a plurality of stators (<NUM>) extending radially from the hub to the cylinder,
the hub and each of the stators are disposed rearward of the propeller,
the propeller unit and the motor are configured to be supported by a rear wing (<NUM>) of the aircraft,
the propeller unit is disposed rearward of the motor, and
the hub is connected to the rotation shaft of the motor via a bearing (<NUM>, <NUM>).