JP2019209929A - Frame assembly - Google Patents

Abstract

To provide a rotary wing frame assembly which can radiate heat from a motor while achieving weight reduction.SOLUTION: A frame assembly 1 for a rotorcraft includes a bottom plate 11 which is a printed circuit board on which a control circuit for controlling a motor which rotates rotary winds 21 may be mounted. The motor can be mounted on the bottom plate and a cupper foil is disposed over an entire part thereof (except a portion where the circuit is formed) as a cooling structure for cooling the motor mounted thereon. Creating communication between the heat-conductive copper foil and the circuit can diffuse heat of the circuit. The structure can radiate heat from the motor while achieving weight reduction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a frame assembly.

  Unmanned air vehicles with multiple propellers are used in various fields. The propeller is rotated by a motor. In order to prevent motor failure, heat dissipation of the motor is considered. Patent Document 1 discloses an unmanned aerial vehicle in which a heat-dissipating waterproof lid is provided at the upper end of a motor, and the motor dissipates heat by an airflow discharged from the heat-dissipating waterproof lid.

Special table 2017-535478 gazette

  However, in the unmanned aerial vehicle described in Patent Document 1, an increase in weight is inevitable because a heat-dissipating waterproof lid is attached to each motor.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a frame assembly capable of radiating heat from a motor while reducing the weight.

  A main invention of the present invention for solving the above problems is a frame assembly for a rotary wing machine, comprising a printed circuit board capable of mounting a control circuit for controlling a motor for rotating the rotary wing, wherein the printed circuit board is The motor can be mounted, and a cooling structure for cooling the mounted motor is provided.

  Other problems and solutions to be disclosed by the present application will be made clear by the embodiments of the invention and the drawings.

  According to the present invention, the motor can be dissipated while reducing the weight.

It is a bottom view of the frame assembly 1 which concerns on one Embodiment of this invention. It is a top view of the frame assembly 1 which concerns on one Embodiment of this invention. 1 is a perspective view of a frame assembly 1 according to an embodiment of the present invention. 4 is a schematic diagram showing a cross section of a motor mount 111 in a state where a motor 20 is mounted on a bottom plate 11. FIG. It is an enlarged view of the motor mount 111 vicinity. It is a figure explaining the heat conduction from the control circuit. It is a perspective view of the motor mount 111 showing the state which shaved the paint 141. FIG. It is AA sectional drawing of FIG. It is sectional drawing of the motor mount 111 at the time of providing the thermal radiation VIA24.

  The contents of the embodiment of the present invention will be listed and described. An aircraft according to an embodiment of the present invention has the following configuration.

[Item 1]
A frame assembly for a rotorcraft,
It has a printed circuit board that can be mounted with a control circuit that controls the motor that rotates the rotor blades.
The printed circuit board can be mounted with the motor, and includes a cooling structure for cooling the mounted motor;
A frame assembly characterized by the above.

[Item 2]
The frame assembly according to claim 1, wherein
The printed circuit board includes a heat transfer layer;
The cooling structure exposes the heat transfer layer to a mounting surface of the motor;
A frame assembly characterized by the above.

[Item 3]
The frame assembly according to claim 2, wherein
The heat transfer layer is a metal;
A frame assembly characterized by the above.

[Item 4]
The frame assembly according to claim 1, wherein
The printed circuit board includes a heat transfer layer;
The heat transfer layer is in communication between a portion where the control circuit is mounted and a portion where the cooling structure is provided;
A frame assembly characterized by the above.

<Details of the embodiment>
Hereinafter, a frame assembly 1 according to an embodiment of the present invention will be described with reference to the drawings. The frame assembly 1 of this embodiment constitutes a frame of the flying object. FIG. 1 is a bottom view of the frame assembly 1 according to this embodiment, and FIG. 2 is a top view of the frame assembly 1 according to this embodiment. FIG. 3 is a perspective view of the frame assembly 1 according to the present embodiment. The vertical direction on the paper surface of FIGS. 1 and 2 is the front-rear direction of the flying object.

  The frame assembly 1 includes a bottom plate 11 and a top plate 12 that is substantially parallel to the bottom plate 11. The bottom plate 11 is a copper core printed circuit board on which circuits are formed on both sides. For example, electronic components such as a flight controller that controls the motor 20 are mounted on the bottom plate 11. In the present embodiment, a control circuit 19 including a flight controller is mounted on the front and rear central portions of the central portion 115 of the bottom plate 11. In the example of FIG. 1, a cover 18 that protects the control circuit 19 is disposed below the portion where the control circuit 19 is mounted. In the bottom plate 11, a copper foil and a circuit pattern are formed on a fiber-reinforced substrate, and an insulating layer (resist) is formed on the surface layer. The substrate is, for example, a glass epoxy substrate (FR4; Flame Retardant Type 4). An insulating layer is not provided in a portion where electronic components are arranged on the bottom plate 11 and soldered, and the copper foil is plated. In the present embodiment, the top plate 12 is also the same printed board as the bottom plate 11. In the frame assembly 1 of this embodiment, the bottom plate 11 and the top plate 12 are provided with copper foil throughout (except for the part where the circuit is formed). The bending strength of the bottom play 11 and the top plate 12 can be increased using the tension of the copper foil. Further, the heat of the circuit can be diffused by communicating the heat conductive copper foil with the circuit. That is, the copper foil portion of the printed circuit board is generally used for constituting a circuit and a noise shield, but the frame assembly 1 of this embodiment is also used for frame reinforcement and heat dissipation. The bottom plate 11 may be a metal core substrate or a metal base substrate having a metal such as copper as a core.

  The bottom plate 11 includes four motor mounts 111 on which the motor 20 can be mounted. 1 to 3 show a state in which the motor 20 is mounted on the motor mount 111. The motor mount 111 is supported by the arms 112 and 113. The arms 112 and 113 are formed integrally with the bottom plate 11. The arms 112 and 113 are curved outward of the bottom plate 11. Thereby, it is possible to withstand a force from the side surface at the time of a collision in the side surface direction.

  The bottom plate 11 having a plurality of motor mounts 111 is point-symmetric. Thereby, it is possible to make it difficult for the operator to feel the blur of the center of gravity when operating the flying object. Furthermore, the frame assembly 1 is symmetric in the front-rear direction and in the left-right direction. As a result, the symmetry of the control characteristics of the flying object is ensured, and it is possible to reduce the uncomfortable feeling of operation, and it is also possible to easily maintain the level even when the flying object falls. Therefore, when the flying object falls, it is expected to decelerate by air resistance, and damage damage can be reduced.

  The motor mount 111 is formed to be the same as or larger than the bottom surface of the motor 20. Thereby, the motor 20 can be protected at the time of a collision.

  A propeller guard 114 is provided at the front-rear direction end of the bottom plate 11, and a propeller guard 121 is provided at the front-rear direction end of the top plate 12. The propeller guards 114 and 121 protect the rotor 20 (propeller) 21 attached to the motor 20 and the motor 20 when the flying object collides.

  The arm 112 and the arm 113 are arranged on a substantially straight line and extend from the motor mount 111 in a substantially reverse direction. That is, the arm 112 and the arm 113 support the motor mount 111 at a position that is substantially opposed. Since the arm 112 and the arm 113 support the motor mount 111 at a substantially opposite position, the motor mount 111 can be stably supported. Therefore, even when the motor 20 rotates, it can withstand the stress repelling the thrust by the propeller 21. Further, vibration due to the operation of the motor 20 can be suppressed. Therefore, the strength of the frame assembly 1 can be improved, the motor 20 can be stabilized, and consequently the flight of the flying object can be stabilized. Further, the area of the arm that blocks the wake of the propeller can be reduced, and the energy efficiency can be improved. The arm 112 and the arm 113 do not have to be on a straight line, but geometrically, a line connecting the midpoint of the two support points and the action point (the center of the motor 20) is equivalent to the cantilever arm. The closer the two arms 112 and 113 are to a straight line, the shorter the arm length in the case of a cantilever arm, and the more difficult it is to bend. In calculation, the acute angle formed by the arm 112 and the arm 113 is preferably 20 degrees or less.

  The arms 112 and 113 extend in the longitudinal direction of the reinforcing fibers included in the insulating layer of the bottom plate 11. Thereby, the strength of the insulating layer of the bottom plate 11 can be effectively utilized.

  A bridge 119 is provided between the front and rear arms 113 on each of the left and right sides of the bottom plate 11. Thereby, the torsional rigidity of the frame assembly 1 is improved.

  An opening 120 is formed by the arm 112, the motor mount 111, the arm 113, the central portion 115, and the propeller guard 114. By providing the opening 120, the airflow generated when the propeller 21 is rotated can be prevented from being blocked, and the weight of the frame assembly 1 can be reduced.

  The propeller guard 114 of the bottom plate 11 ensures the rigidity to withstand the stress when the frame assembly 1 receives a force from the front or obliquely forward by the tension of the camera guard 117 and the support of the arm 112. Further, the propeller guard 121 of the top plate 12 ensures the rigidity to withstand the stress when the frame assembly 1 receives a force from the front or obliquely forward by the tension of the camera guard 123. Since the propeller guard 121 has lower rigidity than the propeller guard 114, the outer end portion 118 of the propeller guard 114 of the bottom plate 11 protrudes outward from the end portion 124 of the propeller guard 121 of the top plate 12.

  A camera 30 can be mounted in the vicinity of the front end portion on the central portion 115 of the bottom plate 11. A recess 116 is formed at the front end of the bottom plate 11, and a similar recess 122 is formed at the front end of the top plate 12. Camera guards 117 and 123 are provided on the bottom plate 11 and the top plate 12, respectively, so that the camera 30 does not protrude from the frame assembly 1 when the camera 30 is mounted. Thereby, the camera 30 can be protected at the time of a collision. The concave portions 116 and 122 have tapered left and right ends so that the bottom plate 11 does not enter the angle of view of the camera 30.

  Since the camera 30 is mounted on the central portion 115, the deviation of the center of gravity by the camera 30 during the roll operation is suppressed. Therefore, it is possible to bring a stable flight to the flying object. In the present embodiment, it is assumed that the center of gravity of the flying vehicle on which the camera 30 is mounted substantially coincides with the center of gravity of the camera 30. Thereby, when the flying object is flying, it is possible to reduce a sense of incongruity of the image taken in the first person view (FPV) taken by the camera 30.

  Between the bottom plate 11 and the top plate 12, two vertical plates 13 and a plurality of spacers 14 that are substantially perpendicular to the bottom plate 11 and the top plate 12 are arranged, and the bottom plate 11 and the top plate 12 are separated from each other. The The vertical plate 13 can also be the same printed circuit board as the bottom plate 11 and the top plate 12. Spacers 16 are also arranged between the two vertical plates 13. It is assumed that the distance at which the bottom plate 11 and the top plate 12 are separated is equal to or greater than the height at which the propeller 21 is mounted on the motor 20. The vertical plate 13 has a plate shape and can reduce air resistance when the flying object moves up and down.

  The spacer 14 is screwed with the screw 15 and is engaged with each of the bottom plate 11 and the top plate 12 by the screw 15. The spacer 16 is screwed with the screw 17 and is engaged with the vertical plate 13 by the screw 17. The diameters of the screw holes provided in the bottom plate 11, the top plate 12, and the vertical plate 13 are larger than the diameters of the screws 15 and 17. As a result, even when an impact is applied to the frame assembly 1, the screws 15 and 17 can be hardly loaded. Therefore, it is possible to avoid the stress from the highly rigid screws 15 and 17 from being concentrated on the screw hole portions of the bottom plate 11, the top plate 12, and the vertical plate 13, and to prevent breakage.

  The bottom plate 11 is provided with slits at the positions of the front fitting portion 131 and the rear fitting portion 132, and is fitted with the protruding portion of the vertical plate 13. The top plate 12 is also provided with slits at the positions of the front fitting portion 133 and the rear fitting portion 134, and fits with the protruding portion of the vertical plate 13. Thus, the bottom plate 11, the vertical plate 13, and the top plate 12 constitute a box structure. Therefore, the strength of the entire frame assembly 1 can be ensured. On the other hand, the bottom plate 11 and the top plate 12 and the vertical plate 13 form a box structure by fitting, and there is no need to perform processing such as screwing using screws or bonding with an adhesive, screws, etc. Therefore, the frame assembly 1 can be kept lightweight. In addition, a spacer 14 is provided in the vicinity of each fitting portion 131, 132, 133, and 134. When the frame assembly 1 receives an impact and the bottom plate 11 or the top plate 12 bends, the fitting portions 131, 132, 133, and 134 may be disengaged. , 132, 133, and 134, it is expected that the amount of deformation of the fitting portion is reduced, and the fitting can be strengthened.

  The vertical plate 13 and the bottom plate 11 abut on the stress receiving portion 135. The outer edge of the opening 120 includes two arc portions 136 and 137, and the stress receiving portion 135 is provided at a connection portion between the arc portions 136 and 137. The stress receiving portion 135 is configured to receive the stress from the vertical plate 13. The arc portions 136 and 137 have different radii, and the radius of the arc portion 137 near the center of the bottom plate 11 is shorter than the radius of the arc portion 136. Thereby, in the contact part 136, it is possible to increase the area that receives stress from the vertical plate 13, and the strength of the frame assembly 1 can be improved.

  FIG. 4 is a schematic diagram showing a cross section of the motor mount 111 in a state where the motor 20 is mounted on the bottom plate 11. The bottom plate 11 includes an epoxy glass layer 143. Copper foils 142 are disposed above and below the epoxy glass layer 143. A coating 141 serving as an insulating layer is applied to the outer surface of the copper foil 142, and a circuit is formed on the surface of the coating 141. Is arranged. The motor 20 is placed on the outer surface of the paint 141 on the upper surface, and is fixed by screws 22 that penetrate the bottom plate 11. The screw hole into which the screw 22 is inserted may be processed through-hole. When the screw 22 is a material having thermal conductivity such as a metal or a high thermal conductive resin, the heat of the motor 20 is transmitted to the copper foil 142 through the screw 22 as indicated by an arrow 211, and the screw 22 is transferred to the thermal conduction portion 212. Then, heat is conducted to the copper foil 142 and is diffused through the copper foil 142 as indicated by an arrow 213.

  FIG. 5 is an enlarged view of the vicinity of the lower left motor mount 111 displayed by a dotted line portion in FIG. As described above, the heat of the motor 20 is transmitted to the copper foil 142 via the screw 22. The arm 112 conducts heat in the direction of the arrow 152, and the arm 113 conducts heat in the direction of the arrow 153. Here, the propeller 21 rotates in the range indicated by the dotted circle 151, and the airflow generated by the rotation of the propeller 21 flows downward. That is, the airflow generated by the rotation of the propeller 21 flows toward the arms 112 and 113. Therefore, the arms 112 and 113 are cooled by the airflow. That is, the arms 112 and 113 arranged below the propeller 21 have a function of cooling the heat transmitted through the copper foil 142 disposed inside the arms 112 and 113.

  FIG. 6 is a diagram illustrating heat conduction from the control circuit 19. The copper foil 142 of the bottom plate 11 communicates between the arms 113 and the front and rear central portions of the central portion 15 where the control circuit 19 is mounted. Accordingly, heat generated by (at least part of) the control circuit 19 is diffused in the direction indicated by the arrows 154 to 157. As described above, since the airflow generated by the rotation of the propeller 21 cools the arm 13, at least the arm 113 also functions as a cooling structure of the control circuit 19.

  As described above, in the frame assembly 1 of the present embodiment, the motor 20 is screwed onto the bottom plate 11 including the copper foil 142 serving as the heat conductive layer with the heat conductive screw 22, so that the propeller 21 A cooling structure in which the generated airflow is used for cooling can be formed. When the motor 20 is heated to a high temperature, performance degradation due to a decrease in magnetic force, and thus failure such as copper loss and iron loss may occur. According to the frame assembly 1 of the present embodiment, the copper foil 142 of the bottom plate 11 is used. Since the cooling structure can be configured, the motor 20 can be cooled while keeping the frame assembly 1 lightweight without adding cooling components. Therefore, since the failure of the motor 20 can be suppressed and the performance deterioration of the motor 20 can be prevented, the safety of the flying object to which the frame assembly 1 is applied can be improved and the performance can be improved.

  Further, the cooling efficiency can be further increased by bringing the motor 20 and the copper foil 142 into direct contact. Specifically, the paint 141 is scraped off at the motor mount 111 and the bottom surface 23 of the motor 20 and the copper foil 142 are brought into contact with each other. FIG. 7 is a perspective view of the motor mount 111 showing a state in which the paint 141 is shaved, and FIG. 8 is a cross-sectional view taken along the line AA of FIG. The paint 141 on the upper surface of the motor mount 111 is scraped to form an exposed surface 148 on the upper surface of the copper foil 142. When the motor 20 is mounted on the motor mount 111, the bottom surface 23 of the motor 20 contacts the exposed surface 148. Thereby, the contact area which the motor 20 which is a heat generating body, and the copper foil 142 which is a heat conductive layer contact can be enlarged. Heat from the motor 20 is conducted directly from the motor 20 to the copper foil 142 in the region 214 where the bottom surface 23 and the exposed surface 148 abut. Accordingly, the thermal conductivity is higher than that when passing through the screw 22, and the amount of heat conducted as indicated by an arrow 213 in the copper foil 142 in contact with the motor 20 is increased. Therefore, the heat of the motor 20 can be diffused more quickly, and the motor 20 can be cooled more effectively. As measured by the inventor, the temperature of the motor 20 was about 70 to 90 degrees before the exposed surface 148 was cut out. However, after the exposed surface 148 was cut out, the motor 20 was cut. The temperature of was maintained at about 30 to 40 degrees. Thus, the cooling efficiency of the motor 20 is improved by providing the exposed surface 148 in the cooling structure.

  Furthermore, the heat radiation effect can be enhanced by providing the heat radiation VIA 24 on the bottom plate 111. FIG. 9 is a cross-sectional view of the motor mount 111 when the heat dissipation VIA 24 is provided. As described above, the heat from the motor 20 is directly conducted from the motor 20 to the copper foil 142 in the region 214 where the bottom surface 23 of the motor 20 and the copper foil 142 are in contact with each other. By providing the heat dissipating VIA 24 in the vicinity of the motor mount 111, the conducted heat moves through the copper foil 142 as indicated by the arrow 213, passes through the heat dissipating VIA 24, and is conducted to the other copper foil 142 as indicated by the arrow 216. Can be. Therefore, it is expected that the heat dissipation effect is further improved.

  Further, as indicated by an arrow 216, the copper foil 142 (the upper copper foil 142 in FIG. 9) that does not directly contact the bottom surface 23 of the motor 20, and the copper foil 142 (the upper copper foil 142 in FIG. 9) that contacts the bottom surface 23 of the motor 20. Heat is also conducted in the direction of the copper foil 142). Therefore, the heat conducted through the screw 22 can be diffused in the vertical direction, and a more effective heat dissipation effect is expected.

  The heat dissipation VIA 24 is preferably provided in the vicinity of the motor 20 that is a heating element. For example, the heat dissipation VIA 24 may be provided at the position of the exposed surface 148 that contacts the bottom surface 23 of the motor 20. Further, the heat dissipation VIA 24 is preferably provided in a place included in a range indicated by a circle 151 in FIG. In this case, since the airflow from the propeller 21 hits the heat dissipation VIA 24, the cooling effect can be improved.

  Although the present embodiment has been described above, the above embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  For example, in the present embodiment, the bottom plate 11 and the top plate 12 are substantially parallel to each other, but they may be spaced apart at unequal intervals. Further, the bottom plate 11 and the top plate 12 may be curved instead of being planar.

  In the present embodiment, four motor mounts 111 are provided on the bottom plate 11. However, the present invention is not limited to this, and an arbitrary number of motor mounts 111 may be provided.

  In the present embodiment, the propeller guard 114 protects the propeller 21 in the front-rear direction, but the propeller 21 can be protected by attaching a separate propeller guard to the side surface (left-right direction). Is possible. The propeller guard 114 is formed integrally with the bottom plate 11 and can disperse the stress on the arm 113. On the other hand, the propeller guard on the side surface is not formed integrally but is a detachable part. Weight reduction as a body can be achieved. In addition, it is possible to easily replace the propeller guard that is highly likely to be damaged during a collision.

  In this embodiment, the arms 112 and 113 both extend in the longitudinal direction of the reinforcing fiber, but only one of them extends in the longitudinal direction of the reinforcing fiber and the other extends in a different direction. It may be.

  In the present embodiment, the center of gravity of the flying object on which the camera 30 is mounted substantially coincides with the center of gravity of the camera 30, but the center of gravity of the camera 30 may be on the center line in the front-rear direction of the bottom plate 11. In this case, it is possible to reduce the FPV discomfort at least during the roll operation of the flying object.

  In the present embodiment, the bottom plate 11, the top plate 12, and the vertical plate 13 are printed boards. However, at least one of the top plate 12 and the vertical plate 13 may be a different material. For example, at least one of the top plate 12 and the vertical plate 13 can be an epoxy resin plate including glass fibers not provided with a copper foil.

1 Frame assembly 11 Bottom plate 12 Top plate 13 Vertical plate 14 Spacer 20 Motor 21 Propeller 22 Screw 23 Bottom surface 24 Heat dissipation VIA
30 Camera 111 Motor mount 112 Arm 113 Arm 114 Propeller guard 115 Center 116 Recess 117 Camera guard 118 Outer end 119 Bridge 120 Opening 121 Propeller guard 122 Recess 123 Camera guard 124 End 131 Front fitting part 132 Rear fitting Part 133 Front side fitting part 134 Back side fitting part 135 Stress receiving part 141 Paint 142 Copper foil 143 Epoxy glass layer 148 Exposed surface

Claims (4)

A frame assembly for a rotorcraft,
It has a printed circuit board that can be mounted with a control circuit that controls the motor that rotates the rotor blades.
The printed circuit board can be mounted with the motor, and includes a cooling structure for cooling the mounted motor;
A frame assembly characterized by the above. The frame assembly according to claim 1, wherein
The printed circuit board includes a heat transfer layer;
The cooling structure exposes the heat transfer layer to a mounting surface of the motor;
A frame assembly characterized by the above. The frame assembly according to claim 2, wherein
The heat transfer layer is a metal;
A frame assembly characterized by the above. The frame assembly according to claim 1, wherein
The printed circuit board includes a heat transfer layer;
The heat transfer layer is in communication between a portion where the control circuit is mounted and a portion where the cooling structure is provided;
A frame assembly characterized by the above.