JP2021023077A - Brushless motor - Google Patents

Abstract

To provide a brushless motor capable of reducing an axial load applied to a ball bearing, ensuring the axial rigidity of a shaft, and dampening the axial vibration generated in the shaft.SOLUTION: A motor 10 includes: an annular stator 22; a rotor 24 having a rotor housing 64 that accommodates the stator 22; a shaft 32 fixed to the rotor housing 64; and a base member 26 having a cylindrical bearing accommodating portion 70 inserted inside the stator 22. A first recess 80 that opens on one side in an axial direction of the bearing accommodating portion 70 is formed inside the bearing accommodating portion 70, and a first ball bearing 28 in which the shaft 32 is inserted is housed in the first recess 80. A plurality of laminated wave washers 86 are provided between the bottom surface of the first recess 80 and the first ball bearing 28 in the axial direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a brushless motor.

In recent years, electric aircraft (hereinafter referred to as airplanes) represented by small aircraft (small mobility for a small number of people), unmanned aerial vehicles (UAV), drones, flying robots, etc. have been used for inspection, surveying, agriculture, transportation, disaster prevention, passengers, etc. It is expected to have a wide range of uses.

Most of the motors for airplanes used for these are driven mainly by limited electric power from batteries. In order to enhance the value of airplanes, such as long flight, increased load capacity, and improved mobility (control stability in strong winds), motors for airplanes are lightweight, high output, high efficiency, and highly cooled by self-wind pressure. Performance is important.

Furthermore, motors for airplanes are also required to have support rigidity for the motor itself to support its own weight, and vibration resistance such as supporting the rotating shaft so that it does not shake even if some propeller imbalance occurs. .. Most of the current motors for airplanes have a fixed axial position of ball bearings in order to obtain high axial rigidity while simplifying the structure.

In such a motor, in the combination of a base member made of light metal such as aluminum or magnesium and a shaft made of iron or stainless steel supported by the base member, when the motor continuously operates and becomes a high temperature state, Due to the difference in linear expansion (thermal expansion) between aluminum and iron, an axial load may be applied to the pair of ball bearings that support the shaft. On the other hand, when the temperature is low, the difference in contraction between the base member and the shaft due to the low temperature causes play in the axial fixing of the ball bearing, which may reduce the shaft rigidity of the shaft.

Here, in the technique described in Patent Document 1, one wave washer that presses one ball bearing in the axial direction is adopted. However, there is a problem that the axial vibration generated in the shaft is difficult to be attenuated by using only one wave washer.

JP-A-2017-034933

The present invention has been made in view of the above circumstances, and can reduce the axial load applied to the ball bearings, secure the axial rigidity of the shaft, and attenuate the axial vibration generated in the shaft. An object of the present invention is to provide a brushless motor capable of providing a brushless motor.

The brushless motor according to claim 1 has an annular stator, a rotor having a rotor housing for accommodating the stator, a shaft fixed to the rotor housing, and a tubular bearing accommodating inserted inside the stator. A ball having a base member having a portion and a recess formed inside the bearing housing portion that opens on one side in the axial direction of the bearing housing portion, and the shaft is inserted inside the recess. A bearing is housed, and a plurality of laminated spring washers are provided between the bottom surface of the recess and the ball bearing in the axial direction.

According to this brushless motor, a plurality of laminated spring washers are provided between the bottom surface of the recess formed in the bearing accommodating portion and the axial direction of the ball bearing. Therefore, for example, when the base member having the bearing accommodating portion is formed of a light metal such as aluminum or magnesium and the shaft is formed of iron or stainless steel or the like, the linear expansion difference (heat) between the base member and the shaft due to high temperature is generated. Even when an expansion difference) occurs, the stacked spring washers are elastically compressed to absorb the axial load applied to the ball bearings, so that the axial load applied to the ball bearings can be reduced.

Further, even when a shrinkage difference occurs between the base member and the shaft due to low temperature, it is possible to suppress the occurrence of play in the axial fixing of the ball bearing due to the generation of elastic force by the plurality of spring washer, so that the shaft Axial rigidity can be secured.

Further, when axial vibration occurs in the shaft, the axial vibration generated in the shaft can be damped by the damping effect due to the frictional energy between the stacks of the plurality of spring washers.

As described in claim 2, in the brushless motor according to claim 1, the first recess as the recess and the opening on the other side in the axial direction of the bearing housing are inside the bearing housing. A first ball bearing as the ball bearing is housed in the first recess, and a second ball bearing in which the shaft is inserted is housed in the second recess. The first is between the inner peripheral surface of the first recess and the first ball bearing and the plurality of spring washer in the radial direction, and between the bottom surface of the first recess and the axial direction of the plurality of spring washer. A cushioning material may be provided.

According to this brushless motor, the first is between the inner peripheral surface of the first recess and the radial direction of the first ball bearing and the plurality of spring washer, and between the bottom surface of the first recess and the axial direction of the plurality of spring washer. A cushioning material is provided. Therefore, the axial vibration generated in the shaft can be more effectively damped by the damping effect of the first cushioning material while eliminating the wear caused by the contact between the members.

Further, as described in claim 3, in the brushless motor according to claim 2, the distance between the inner peripheral surface of the second recess and the second ball bearing in the radial direction and the bottom surface of the second recess. A second cushioning material may be provided between the second ball bearing and the axial direction.

According to this brushless motor, in addition to the first cushioning material, between the inner peripheral surface of the second recess and the second ball bearing in the radial direction, and between the bottom surface of the second recess and the second ball bearing in the axial direction. Is provided with a second cushioning material. Therefore, the axial vibration generated in the shaft can be more effectively damped by the damping effect of the first cushioning material and the second cushioning material while eliminating the wear caused by the contact between the members.

Further, as described in claim 4, in the brushless motor according to claim 3, a third cushioning material may be provided between the laminated layers of the plurality of spring washers.

According to this brushless motor, a third cushioning material is provided between the laminated layers of the plurality of spring washer. Therefore, while eliminating wear due to contact between the plurality of spring washer, the damping effect of the third cushioning material provided between the stacking of the plurality of spring washer further improves the damping effect against the axial vibration generated in the shaft. be able to.

Further, as described in claim 5, in the brushless motor according to claim 3 or 4, the inner peripheral surface of the first recess has a concave first reservoir that opens inside the first recess. A portion is formed, a concave second reservoir that opens inside the second recess is formed on the inner peripheral surface of the second recess, and the first cushioning material is reservoir in the first reservoir. The second cushioning material may be stored in the second storage portion.

According to this brushless motor, a concave first reservoir that opens inside the first recess is formed on the inner peripheral surface of the first recess, and the first cushioning material is formed in the first reservoir. It is stored. Therefore, by storing the first cushioning material in the first reservoir, the distance between the inner peripheral surface of the first recess and the first ball bearing and the plurality of spring washer in the radial direction, and the bottom surface of the first recess and the plurality of spring washer. The first cushioning material can be distributed in just proportion between the axial directions of and. As a result, the damping effect of the first cushioning material can be effectively exerted.

Similarly, a concave second reservoir that opens inside the second recess is formed on the inner peripheral surface of the second recess, and the second cushioning material is stored in this second reservoir. .. Therefore, by storing the second cushioning material in the second reservoir, the distance between the inner peripheral surface of the second recess and the second ball bearing in the radial direction, and the shaft between the bottom surface of the second recess and the second ball bearing. The second cushioning material can be distributed between the directions in just proportion. As a result, the damping effect of the second cushioning material can be effectively exerted.

It is a perspective view of the airplane device which concerns on one Embodiment of this invention. It is a vertical sectional view of the motor which concerns on one Embodiment of this invention. It is an enlarged view of the main part of the motor of FIG. 2A and 2B are views showing a first ball bearing and its peripheral portion in the motor of FIG. 2, where FIG. 2A is a sectional view taken along line F4A-F4A of FIG. 2B, and FIG. 2B is a vertical sectional view. 2A is a view showing a second ball bearing and its peripheral portion in the motor of FIG. 2, where FIG. 2A is a sectional view taken along line F5A-F5A of FIG. 2B, and FIG. 2B is a vertical sectional view. It is a figure which compares the structure and the damping characteristic of the 1st ball bearing and the peripheral part with respect to the motor which concerns on one Embodiment of this invention, and the motor which concerns on 1st comparative example and 2nd comparative example.

First, a schematic configuration of the airplane device 1 according to the embodiment of the present invention will be described.

The airplane device 1 (electric multicopter) of the present embodiment shown in FIG. 1 is a personal mobility capable of flying, and includes a main body unit 2 and a plurality of propulsion units 3. The arrow FR indicates the front side in the front-rear direction of the airplane device 1, the arrow LH indicates the left side in the left-right direction of the airplane device 1, and the arrow UP indicates the upper side in the vertical direction of the airplane device 1.

The main body 2 has a cabin 4 and a pair of legs 5. The cabin 4 is configured in a box shape. Crew members can board the cabin 4. The pair of legs 5 are provided on the lower side of the cabin 4.

The number of the plurality of propulsion units 3 is 4, as an example. The plurality of propulsion portions 3 are symmetrically arranged in the front-rear and left-right directions of the main body portion 2. That is, the first propulsion unit 3 is arranged on the left front side of the main body unit 2, the second propulsion unit 3 is arranged on the right front side of the main body unit 2, and the third propulsion unit 3 is arranged. The fourth propulsion unit 3 is arranged on the left rear side of the main body portion 2, and the fourth propulsion unit 3 is arranged on the right rear side of the main body portion 2.

Each propulsion unit 3 has a rod 8, a support member 9, a motor 10, and a propeller 11. The base end portion of each rod 8 is fixed to the main body portion 2. The rod 8 of the propulsion portion 3 on the left front side extends toward the left front side of the main body portion 2, and the rod 8 of the propulsion portion 3 on the right front side extends toward the right front side of the main body portion 2. The rod 8 of the propulsion portion 3 on the side extends toward the left rear side of the main body portion 2, and the rod 8 of the propulsion portion 3 on the right rear side extends toward the right rear side of the main body portion 2.

Each support member 9 is formed in a plate shape. Each of the support members 9 is fixed to the tip of each rod 8 with the vertical direction of the main body 2 as the plate thickness direction. The motor 10 of each propulsion unit 3 is supported by the support member 9 with the vertical direction of the main body unit 2 as the axial direction. As will be described in detail later, the motor 10 has a motor body 34 having a rotor and a stator, and a shaft 32 that rotates integrally with the rotor. The plurality of motors 10 have the same configuration.

The motor 10 on the left front side and the motor body 34 of the motor 10 on the right front side are arranged on the lower side of the support member 9, and are fixed to the support member 9 with one side in the axial direction (arrow A1 side) facing upward. ing. On the other hand, the motor 10 on the left rear side and the motor body 34 of the motor 10 on the right rear side are arranged on the upper side of the support member 9, and the support member 9 is in a state where the other side in the axial direction (arrow A2 side) faces upward. It is fixed to. The shaft 32 extends upward from the motor main body 34, and a propeller 11 is fixed to the upper end of the shaft 32. The motor 10 and the propeller 11 constitute a thrust generator 12 of the airplane device 1. Each motor 10 is an example of a "brushless motor".

Subsequently, a specific configuration of the motor 10 will be described.

As shown in FIG. 2, the motor 10 is an outer rotor type brushless motor, and includes a stator 22, a rotor 24, a base member 26, a first ball bearing 28, a second ball bearing 30, and a shaft 32. To be equipped. The arrow A1 side indicates one side in the axial direction of the motor 10, and the arrow A2 side indicates the other side in the axial direction of the motor 10. The axial direction of the motor 10 corresponds to the vertical direction of the above-mentioned airplane device 1 (see FIG. 1).

The stator 22, rotor 24, and base member 26 constitute the motor body 34. The stator 22 has a stator core 36 and a plurality of winding winding portions 38. The stator core 36 has an annular portion 40 and a plurality of teeth portions 42 extending radially around the annular portion 40. Insulators (not shown) are attached to the plurality of teeth portions 42. A winding is wound around each tooth portion 42 via an insulator, whereby a winding winding portion 38 is formed in each tooth portion 42. The entire stator 22 has an annular shape.

The rotor 24 has a rotor member 44, a back yoke 46, and a plurality of magnets 48. The rotor member 44 is formed in a substantially disk shape, and is arranged on the arrow A2 side of the stator 22 so as to face the stator 22. A plurality of cooling holes 50 penetrating in the axial direction of the rotor member 44 are formed at a portion of the rotor member 44 facing the winding winding portion 38. The plurality of cooling holes 50 are formed side by side in the circumferential direction of the rotor member 44.

A through hole 52 penetrating the rotor member 44 in the axial direction is formed in the central portion of the rotor member 44, and a shaft 32 is inserted into the through hole 52. Further, a protruding portion 54 protruding toward the arrow A2 side of the rotor member 44 is formed in the central portion of the rotor member 44, and a plurality of screw holes 56 extending in the radial direction of the rotor member 44 are formed in the protruding portion 54. Is formed.

The plurality of screw holes 56 communicate with the through holes 52. Set screws 58 (set screws) are screwed into the plurality of screw holes 56, respectively. The tip of each set screw 58 is inserted into a plurality of recesses 60 formed in the shaft 32, whereby the rotor 24 is fixed to the shaft 32.

The back yoke 46 is formed in an annular shape. The back yoke 46 is fixed to the outer peripheral portion of the rotor member 44 and surrounds the periphery of the stator 22. The rotor member 44 and the back yoke 46 form a bottomed cylindrical (ceiling cylindrical) rotor housing 64. A stator 22 is arranged inside the rotor housing 64, and the rotor housing 64 accommodates the stator 22.

A plurality of magnets 48 are fixed to the inner peripheral surface of the back yoke 46. The plurality of magnets 48 are arranged side by side in the circumferential direction of the back yoke 46. Each magnet 48 faces the tip of the teeth portion 42 in the radial direction of the motor 10 and has a gap 66 between the stator 22 (the tip of the teeth portion 42).

The base member 26 (centerpiece) is made of, for example, a light metal such as aluminum or magnesium. The base member 26 has a disk portion 68 and a bearing accommodating portion 70. The disk portion 68 is arranged on the arrow A1 side of the stator 22 so as to face the stator 22. More specifically, the disk portion 68 is formed in a flat concave shape that opens toward the stator 22 side. A cooling hole 72 that penetrates the disk portion 68 in the radial direction is formed on the outer peripheral portion of the disk portion 68.

As described above, the motor 10 of the present embodiment has cooling holes 50 and cooling holes 72 formed in the rotor 24 and the base member 26, respectively. The cooling holes 50 and 72 are communicated with the gap 66, respectively. Then, by performing intake and exhaust through the plurality of cooling holes 50 and 72, a flow of cooling air is formed inside the motor 10, and the inside of the motor 10 is cooled by the flow of the cooling air. It has become. As described above, the motor 10 of the present embodiment is an air-cooled open type.

Further, a lead-out hole 76 penetrating in the radial direction of the disk portion 68 is formed on the outer peripheral portion of the disk portion 68, and a lead electrically connected to the winding winding portion 38 is formed in the lead-out hole 76. The part 78 is inserted. The lead portion 78 is led out to the outside of the motor 10 through the lead-out hole 76.

The bearing accommodating portion 70 projects from the disk portion 68 toward the stator 22 side. The bearing accommodating portion 70 is inserted (press-fitted) inside the annular portion 40 formed in the stator core 36, whereby the stator 22 is supported by the bearing accommodating portion 70. The bearing accommodating portion 70 is formed in a cylindrical shape and is open on both sides in the axial direction.

The first recess 80 is formed in the portion on the inner side of the bearing accommodating portion 70 on the arrow A1 side, and the second recess 82 is formed in the portion on the inner side of the bearing accommodating portion 70 on the arrow A2 side. The first recess 80 is an example of a “recess”. The first recess 80 is open on the arrow A1 side of the bearing accommodating portion 70, and the second recess 82 is open on the arrow A2 side of the bearing accommodating portion 70.

As shown in FIG. 3, the first recess 80 has an inner peripheral surface 80A and a bottom surface 80B, and the second recess 82 has an inner peripheral surface 82A and a bottom surface 82B. A plurality of wave washers 86 and first ball bearings 28 are housed in the first recess 80, and a second ball bearing 30 is housed in the second recess 82.

The first ball bearing 28 has an inner ring 28A, an outer ring 28B, and a ball 28C. The outer ring 28B is arranged on the radial outer side of the inner ring 28A, and the ball 28C is arranged between the inner ring 28A and the outer ring 28B. Similarly, the second ball bearing 30 has an inner ring 30A, an outer ring 30B, and a ball 30C. The outer ring 30B is arranged on the radial outer side of the inner ring 30A, and the ball 30C is arranged between the inner ring 30A and the outer ring 30B. The first ball bearing 28 and the second ball bearing 30 have the same configuration.

A shaft 32 is inserted (press-fitted) inside the inner rings 28A and 30A of the first ball bearing 28 and the second ball bearing 30, whereby the shaft 32 and the rotor 24 are made of the first ball bearing 28 and the first ball bearing 30. It is rotatably supported by the bearing accommodating portion 70 of the base member 26 via the two ball bearings 30. The shaft 32 is made of, for example, iron or stainless steel.

A C ring 90 is attached to the shaft 32. The C ring 90 is arranged on the arrow A1 side of the first ball bearing 28. The C ring 90 extends in a C shape along the circumferential direction of the shaft 32 while being mounted on the shaft 32, and is in contact with the inner ring 28A of the first ball bearing 28 from the arrow A1 side. Further, a protrusion 92 protruding toward the arrow A1 is formed in the central portion of the rotor member 44, and the protrusion 92 is in contact with the inner ring 30A of the second ball bearing 30 from the arrow A2 side.

The plurality of wave washers 86 are an example of "plurality of spring washers" and are laminated in the axial direction. The plurality of wave washers 86 are provided in a state of being elastically compressed and deformed between the bottom surface 80B of the first recess 80 and the outer ring 28B of the first ball bearing 28 in the axial direction.

Further, the motor 10 is provided with a first cushioning material 94, a second cushioning material 96, and a third cushioning material 98. Since the first cushioning material 94 and the second cushioning material 96 are in the form of thin films, they are shown by the alternate long and short dash lines in FIG. 3 (the same applies to FIGS.

The first cushioning material 94 is provided between the inner peripheral surface 80A of the first recess 80 and the first ball bearing 28 and the plurality of wave washers 86 in the radial direction, and the bottom surface 80B of the first recess 80 and the plurality of wave washers 86. It is provided between the axial directions of.

That is, the first cushioning material 94 includes a cushioning portion 94A provided between the inner peripheral surface 80A of the first recess 80, the first ball bearing 28, and the plurality of wave washers 86 in the radial direction, and the bottom surface of the first recess 80. It has a cushioning portion 94B provided between the 80B and the plurality of wave washers 86 in the axial direction. The buffer portion 94A is provided over the entire circumference of the inner peripheral surface 80A of the first recess 80, and the buffer portion 94B is provided over the entire circumference of the bottom surface 80B of the first recess 80. The first cushioning material 94 is made of, for example, rubber or resin, and is, for example, injected or applied. The first cushioning material 94 may be solidified or may be a highly viscous liquid.

The second cushioning material 96 is provided between the inner peripheral surface 82A of the second recess 82 and the second ball bearing 30 in the radial direction, and between the bottom surface 82B of the second recess 82 and the second ball bearing 30 in the axial direction, respectively. It is provided.

That is, the second cushioning material 96 includes a cushioning portion 96A provided between the inner peripheral surface 82A of the second recess 82 and the second ball bearing 30 in the radial direction, and the bottom surface 82B of the second recess 82 and the second ball bearing. It has a cushioning portion 96B provided between the portion 30 and the axial direction. The buffer portion 96A is provided over the entire circumference of the inner peripheral surface 82A of the second recess 82, and the buffer portion 96B is provided over the entire circumference of the bottom surface 82B of the second recess 82. The second cushioning material 96 is made of, for example, rubber or resin, and is, for example, injected or applied. The second cushioning material 96 may be solidified or may be a highly viscous liquid.

The third cushioning material 98 is provided between the layers of the plurality of wave washers 86. That is, the third cushioning material 98 has a plurality of cushioning portions 98A provided between the laminated layers of the plurality of wave washers 86. Further, in the present embodiment, as an example, between the outer ring 28B of the first ball bearing 28 and the plurality of wave washers 86, and between the bottom surface 80B of the first recess 80 and the plurality of wave washers 86 in the axial direction. Also provided with a shock absorber 98A. Each buffer portion 98A is provided over the entire circumference of the wave washer 86. The third cushioning material 98 is, for example, high-viscosity grease. The third cushioning material 98 may be a solidified cushioning material.

Further, as shown in FIG. 4, a plurality of concave first reservoirs 100 that open inside (diameterally inside) of the first recess 80 are formed on the inner peripheral surface 80A of the first recess 80. The plurality of first reservoirs 100 are formed at equal intervals in the circumferential direction of the first recess 80. As an example, each first reservoir 100 is formed over the entire length of the first recess 80 in the axial direction. The first cushioning material 94 is stored in each first storage portion 100. That is, the first cushioning material 94 has a pool portion 94C stored in the first pool portion 100.

Similarly, as shown in FIG. 5, a plurality of concave second reservoirs 102 that open inside (diameterally inside) of the second recess 82 are formed on the inner peripheral surface 82A of the second recess 82. .. The plurality of second reservoirs 102 are formed at equal intervals in the circumferential direction of the second recess 82. As an example, each second reservoir 102 is formed over the entire length of the second recess 82 in the axial direction. The second cushioning material 96 is stored in each of the second storage portions 102. That is, the second cushioning material 96 has a pool portion 96C stored in the second pool portion 102.

Next, the operation and effect of this embodiment will be described.

According to the motor 10 according to the present embodiment, it has at least the following actions and effects (1) to (7).

(1) As shown in FIG. 3, a plurality of laminated wave washers are laminated between the bottom surface 80B of the first recess 80 formed in the bearing accommodating portion 70 and the outer ring 28B of the first ball bearing 28. 86 is provided. Therefore, for example, when the base member 26 having the bearing accommodating portion 70 is formed of a light metal such as aluminum or magnesium and the shaft 32 is formed of iron or stainless steel or the like, the temperature between the base member 26 and the shaft 32 is high. Even when a linear expansion difference (thermal expansion difference) occurs, the stacked wave washer 86 can absorb the axial load applied to the first ball bearing 28 by elastically compressing the first ball bearing 28. The axial load applied to 28 can be reduced.

(2) Even when a shrinkage difference occurs between the base member 26 and the shaft 32 due to low temperature, the plurality of wave washers 86 generate elastic force, so that the first ball bearing 28 is loosely fixed in the axial direction. Since it can be suppressed from occurring, the axial rigidity of the shaft 32 can be ensured.

(3) When axial vibration occurs in the shaft 32, the axial vibration generated in the shaft 32 can be damped by the damping effect due to the frictional energy between the laminated layers of the plurality of wave washers 86.

(4) Between the inner peripheral surface 80A of the first recess 80 and the first ball bearing 28 and the plurality of wave washers 86 in the radial direction, and between the bottom surface 80B of the first recess 80 and the plurality of wave washers 86 in the axial direction. Is provided with, for example, a rubber or resin first cushioning material 94. Further, between the inner peripheral surface 82A of the second recess 82 and the second ball bearing 30 in the radial direction, and between the bottom surface 82B of the second recess 82 and the axial direction of the second ball bearing 30, for example, rubber or A second cushioning material 96 made of resin is provided. Therefore, the axial vibration generated in the shaft 32 can be more effectively damped by the damping effect of the first cushioning material 94 and the second cushioning material 96 while eliminating the wear caused by the contact between the metal members.

(5) A third cushioning material 98 is provided between the laminated layers of the plurality of wave washers 86. Therefore, while eliminating the wear caused by the contact between the plurality of wave washers 86, the damping effect of the third cushioning material 98 provided between the stacking of the plurality of wave washers 86 causes the axial vibration generated in the shaft 32. The damping effect can be further improved.

(6) As shown in FIG. 4, a concave first reservoir 100 that opens inside the first recess 80 is formed on the inner peripheral surface 80A of the first recess 80, and this first reservoir 100 is formed. The first cushioning material 94 is stored in 100. Therefore, by storing the first cushioning material 94 in the first storage portion 100, the distance between the inner peripheral surface 80A of the first recess 80 shown in FIG. 3 and the first ball bearing 28 and the plurality of wave washers 86 in the radial direction. And, the first cushioning material 94 can be spread in just proportion between the bottom surface 80B of the first recess 80 and the plurality of wave washers 86 in the axial direction. As a result, the damping effect of the first cushioning material 94 can be effectively exerted.

(7) As shown in FIG. 5, a concave second reservoir 102 that opens inside the second recess 82 is formed on the inner peripheral surface 82A of the second recess 82, and this second reservoir 102 is formed. The second cushioning material 96 is stored in 102. Therefore, by accumulating the second cushioning material 96 in the second accumulating portion 102, as shown in FIG. 3, the distance between the inner peripheral surface 82A of the second recess 82 and the second ball bearing 30 in the radial direction and The second cushioning material 96 can be spread in just proportion between the bottom surface 82B of the second recess 82 and the second ball bearing 30 in the axial direction. As a result, the damping effect of the second cushioning material 96 can be effectively exerted.

Next, a comparison between the present embodiment and the comparative example will be described.

FIG. 6 shows a first comparative example and a second comparative example in comparison with the above-described present embodiment. The upper row shows a vertical cross-sectional view of the first ball bearing 28 and its peripheral portion in each example, and the lower row shows the relationship between the displacement of the axial vibration generated in the shaft 32 and the time as damping characteristics. A graph is shown.

The first comparative example of FIG. 6 is an example in which one wave washer 86 is provided between the bottom surface 80B of the first recess 80 and the outer ring 28B of the first ball bearing 28 with respect to the present embodiment. As described above, when there is only one wave washer 86, there is a problem that the axial vibration generated in the shaft 32 is difficult to be attenuated as shown in the lower graph G1.

In the second comparative example of FIG. 6, a plurality of laminated wave washers 86 are provided between the bottom surface 80B of the first recess 80 and the outer ring 28B of the first ball bearing 28 with respect to the present embodiment. This is an example in which the third cushioning material 98 is omitted from the stacking of the plurality of wave washers 86.

In this way, when a plurality of laminated wave washers 86 are provided between the bottom surface 80B of the first recess 80 and the outer ring 28B of the first ball bearing 28, friction between the laminated waves washer 86 is provided. Due to the damping effect of energy, the axial vibration generated in the shaft 32 can be damped as shown in the lower graph G2. It should be noted that this second comparative example is an example of comparison with the above-described present embodiment, and a plurality of waves laminated between the bottom surface 80B of the first recess 80 and the outer ring 28B of the first ball bearing 28. It corresponds to the embodiment of the present invention in that the washer 86 is provided.

On the other hand, in the present embodiment of FIG. 6, there is a radial distance between the inner peripheral surface 80A of the first recess 80 and the first ball bearing 28 and the plurality of wave washers 86, and a plurality of bottom surfaces 80B of the first recess 80. A first cushioning material 94 is provided between the wave washer 86 and the wave washer 86, and a third cushioning material 98 is provided between the laminated layers of the plurality of wave washers 86. Therefore, the damping effect of the third cushioning material 98 can be obtained while eliminating the wear caused by the contact between the plurality of wave washers 86. Therefore, as shown in the lower graph G3, the first comparative example and the second comparative example In comparison, the damping effect can be further improved.

Next, a modified example of this embodiment will be described.

In the above embodiment, as an example of the "plurality of spring washers", a plurality of wave washers 86 are provided between the bottom surface 80B of the first recess 80 and the outer ring 28B of the first ball bearing 28. A plurality of spring washers of a type other than the wave washer 86 may be provided in a laminated state.

Further, in the above embodiment, the shaft 32 is press-fitted inside the inner rings 28A and 30A of the first ball bearing 28 and the second ball bearing 30, and the outer rings 28B and 30B of the first ball bearing 28 and the second ball bearing 30 are respectively. Is inserted (non-press-fitted) inside the first recess 80 and the second recess 82. However, the shaft 32 is inserted (non-press-fitted) inside the inner rings 28A and 30A of the first ball bearing 28 and the second ball bearing 30, and the outer rings 28B and 30B of the first ball bearing 28 and the second ball bearing 30 are inserted. It may be press-fitted into the inside of the first recess 80 and the second recess 82.

Further, the shaft 32 is inserted (non-press-fitted) inside the inner rings 28A and 30A of the first ball bearing 28 and the second ball bearing 30, and the outer rings 28B and 30B of the first ball bearing 28 and the second ball bearing 30 are inserted. When press-fitted into the inside of the first recess 80 and the second recess 82, the first cushioning material 94 and the second are between the inner rings 28A and 30A of the first ball bearing 28 and the second ball bearing 30 and the shaft 32. The cushioning material 96 may be provided respectively.

Further, in the above embodiment, the motor 10 is used for the airplane device 1, but may be used for a device other than the airplane device 1.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be variously modified and implemented within a range not deviating from the gist thereof. Is.

1 ... Aircraft, 2 ... Main body, 3 ... Propulsion, 4 ... Cabin, 5 ... Leg, 8 ... Rod, 9 ... Support member, 10 ... Motor, 11 ... Propeller, 12 ... Thrust generator, 22 ... Stator , 24 ... rotor, 26 ... base member, 28 ... first ball bearing, 28A ... inner ring, 28B ... outer ring, 28C ... ball, 30 ... second ball bearing, 30A ... inner ring, 30B ... outer ring, 30C ... ball, 32 ... Shaft, 34 ... motor body, 36 ... stator core, 38 ... winding winding part, 40 ... annular part, 42 ... teeth part, 44 ... rotor member, 46 ... back yoke, 48 ... magnet, 50 ... cooling hole, 52 ... Through hole, 54 ... projecting part, 56 ... screw hole, 58 ... set screw, 60 ... recess, 64 ... rotor housing, 66 ... gap, 68 ... disk part, 70 ... bearing accommodating part, 72 ... cooling hole, 76 ... lead out Hole, 78 ... Lead part, 80 ... First recess, 80A ... Inner peripheral surface, 80B ... Bottom surface, 82 ... Second recess, 82A ... Inner peripheral surface, 82B ... Bottom surface, 86 ... Wave washer (an example of spring washer), 90 ... C ring, 92 ... protrusion, 94 ... first buffer, 94A, 94B ... buffer, 94C ... pool, 96 ... second buffer, 96A, 96B ... buffer, 96C ... pool, 98 ... Three buffer materials, 98A ... buffer, 100 ... first reservoir, 102 ... second reservoir

Claims (5)

With an annular stator,
A rotor having a rotor housing for accommodating the stator, and
The shaft fixed to the rotor housing and
A base member having a tubular bearing accommodating portion inserted inside the stator, and
With
A recess that opens on one side in the axial direction of the bearing accommodating portion is formed inside the bearing accommodating portion.
A ball bearing in which the shaft is inserted is housed in the recess.
A plurality of laminated spring washers are provided between the bottom surface of the recess and the ball bearing in the axial direction.
Brushless motor. Inside the bearing accommodating portion, a first recess as the recess and a second recess opening on the other side in the axial direction of the bearing accommodating portion are formed.
The first ball bearing as the ball bearing is housed in the first recess.
A second ball bearing in which the shaft is inserted is housed in the second recess.
A first cushioning material is provided between the inner peripheral surface of the first recess and the first ball bearing and the plurality of spring washer in the radial direction, and between the bottom surface of the first recess and the axial direction of the plurality of spring washer. Is provided,
The brushless motor according to claim 1. A second cushioning material is provided between the inner peripheral surface of the second recess and the second ball bearing in the radial direction, and between the bottom surface of the second recess and the axial direction of the second ball bearing. Yes,
The brushless motor according to claim 2. A third cushioning material is provided between the laminated layers of the plurality of spring washers.
The brushless motor according to claim 3. On the inner peripheral surface of the first recess, a concave first reservoir that opens inside the first recess is formed.
On the inner peripheral surface of the second recess, a concave second reservoir that opens inside the second recess is formed.
The first cushioning material is stored in the first reservoir.
The second cushioning material is stored in the second reservoir.
The brushless motor according to claim 3 or 4.